1// SPDX-License-Identifier: GPL-2.0
   2/* Copyright (c) 2018 Facebook */
   3
   4#include <uapi/linux/btf.h>
   5#include <uapi/linux/bpf.h>
   6#include <uapi/linux/bpf_perf_event.h>
   7#include <uapi/linux/types.h>
   8#include <linux/seq_file.h>
   9#include <linux/compiler.h>
  10#include <linux/ctype.h>
  11#include <linux/errno.h>
  12#include <linux/slab.h>
  13#include <linux/anon_inodes.h>
  14#include <linux/file.h>
  15#include <linux/uaccess.h>
  16#include <linux/kernel.h>
  17#include <linux/idr.h>
  18#include <linux/sort.h>
  19#include <linux/bpf_verifier.h>
  20#include <linux/btf.h>
  21#include <linux/btf_ids.h>
  22#include <linux/bpf_lsm.h>
  23#include <linux/skmsg.h>
  24#include <linux/perf_event.h>
  25#include <linux/bsearch.h>
  26#include <linux/kobject.h>
  27#include <linux/sysfs.h>
  28
  29#include <net/netfilter/nf_bpf_link.h>
  30
  31#include <net/sock.h>
  32#include <net/xdp.h>
  33#include "../tools/lib/bpf/relo_core.h"
  34
  35/* BTF (BPF Type Format) is the meta data format which describes
  36 * the data types of BPF program/map.  Hence, it basically focus
  37 * on the C programming language which the modern BPF is primary
  38 * using.
  39 *
  40 * ELF Section:
  41 * ~~~~~~~~~~~
  42 * The BTF data is stored under the ".BTF" ELF section
  43 *
  44 * struct btf_type:
  45 * ~~~~~~~~~~~~~~~
  46 * Each 'struct btf_type' object describes a C data type.
  47 * Depending on the type it is describing, a 'struct btf_type'
  48 * object may be followed by more data.  F.e.
  49 * To describe an array, 'struct btf_type' is followed by
  50 * 'struct btf_array'.
  51 *
  52 * 'struct btf_type' and any extra data following it are
  53 * 4 bytes aligned.
  54 *
  55 * Type section:
  56 * ~~~~~~~~~~~~~
  57 * The BTF type section contains a list of 'struct btf_type' objects.
  58 * Each one describes a C type.  Recall from the above section
  59 * that a 'struct btf_type' object could be immediately followed by extra
  60 * data in order to describe some particular C types.
  61 *
  62 * type_id:
  63 * ~~~~~~~
  64 * Each btf_type object is identified by a type_id.  The type_id
  65 * is implicitly implied by the location of the btf_type object in
  66 * the BTF type section.  The first one has type_id 1.  The second
  67 * one has type_id 2...etc.  Hence, an earlier btf_type has
  68 * a smaller type_id.
  69 *
  70 * A btf_type object may refer to another btf_type object by using
  71 * type_id (i.e. the "type" in the "struct btf_type").
  72 *
  73 * NOTE that we cannot assume any reference-order.
  74 * A btf_type object can refer to an earlier btf_type object
  75 * but it can also refer to a later btf_type object.
  76 *
  77 * For example, to describe "const void *".  A btf_type
  78 * object describing "const" may refer to another btf_type
  79 * object describing "void *".  This type-reference is done
  80 * by specifying type_id:
  81 *
  82 * [1] CONST (anon) type_id=2
  83 * [2] PTR (anon) type_id=0
  84 *
  85 * The above is the btf_verifier debug log:
  86 *   - Each line started with "[?]" is a btf_type object
  87 *   - [?] is the type_id of the btf_type object.
  88 *   - CONST/PTR is the BTF_KIND_XXX
  89 *   - "(anon)" is the name of the type.  It just
  90 *     happens that CONST and PTR has no name.
  91 *   - type_id=XXX is the 'u32 type' in btf_type
  92 *
  93 * NOTE: "void" has type_id 0
  94 *
  95 * String section:
  96 * ~~~~~~~~~~~~~~
  97 * The BTF string section contains the names used by the type section.
  98 * Each string is referred by an "offset" from the beginning of the
  99 * string section.
 100 *
 101 * Each string is '\0' terminated.
 102 *
 103 * The first character in the string section must be '\0'
 104 * which is used to mean 'anonymous'. Some btf_type may not
 105 * have a name.
 106 */
 107
 108/* BTF verification:
 109 *
 110 * To verify BTF data, two passes are needed.
 111 *
 112 * Pass #1
 113 * ~~~~~~~
 114 * The first pass is to collect all btf_type objects to
 115 * an array: "btf->types".
 116 *
 117 * Depending on the C type that a btf_type is describing,
 118 * a btf_type may be followed by extra data.  We don't know
 119 * how many btf_type is there, and more importantly we don't
 120 * know where each btf_type is located in the type section.
 121 *
 122 * Without knowing the location of each type_id, most verifications
 123 * cannot be done.  e.g. an earlier btf_type may refer to a later
 124 * btf_type (recall the "const void *" above), so we cannot
 125 * check this type-reference in the first pass.
 126 *
 127 * In the first pass, it still does some verifications (e.g.
 128 * checking the name is a valid offset to the string section).
 129 *
 130 * Pass #2
 131 * ~~~~~~~
 132 * The main focus is to resolve a btf_type that is referring
 133 * to another type.
 134 *
 135 * We have to ensure the referring type:
 136 * 1) does exist in the BTF (i.e. in btf->types[])
 137 * 2) does not cause a loop:
 138 *	struct A {
 139 *		struct B b;
 140 *	};
 141 *
 142 *	struct B {
 143 *		struct A a;
 144 *	};
 145 *
 146 * btf_type_needs_resolve() decides if a btf_type needs
 147 * to be resolved.
 148 *
 149 * The needs_resolve type implements the "resolve()" ops which
 150 * essentially does a DFS and detects backedge.
 151 *
 152 * During resolve (or DFS), different C types have different
 153 * "RESOLVED" conditions.
 154 *
 155 * When resolving a BTF_KIND_STRUCT, we need to resolve all its
 156 * members because a member is always referring to another
 157 * type.  A struct's member can be treated as "RESOLVED" if
 158 * it is referring to a BTF_KIND_PTR.  Otherwise, the
 159 * following valid C struct would be rejected:
 160 *
 161 *	struct A {
 162 *		int m;
 163 *		struct A *a;
 164 *	};
 165 *
 166 * When resolving a BTF_KIND_PTR, it needs to keep resolving if
 167 * it is referring to another BTF_KIND_PTR.  Otherwise, we cannot
 168 * detect a pointer loop, e.g.:
 169 * BTF_KIND_CONST -> BTF_KIND_PTR -> BTF_KIND_CONST -> BTF_KIND_PTR +
 170 *                        ^                                         |
 171 *                        +-----------------------------------------+
 172 *
 173 */
 174
 175#define BITS_PER_U128 (sizeof(u64) * BITS_PER_BYTE * 2)
 176#define BITS_PER_BYTE_MASK (BITS_PER_BYTE - 1)
 177#define BITS_PER_BYTE_MASKED(bits) ((bits) & BITS_PER_BYTE_MASK)
 178#define BITS_ROUNDDOWN_BYTES(bits) ((bits) >> 3)
 179#define BITS_ROUNDUP_BYTES(bits) \
 180	(BITS_ROUNDDOWN_BYTES(bits) + !!BITS_PER_BYTE_MASKED(bits))
 181
 182#define BTF_INFO_MASK 0x9f00ffff
 183#define BTF_INT_MASK 0x0fffffff
 184#define BTF_TYPE_ID_VALID(type_id) ((type_id) <= BTF_MAX_TYPE)
 185#define BTF_STR_OFFSET_VALID(name_off) ((name_off) <= BTF_MAX_NAME_OFFSET)
 186
 187/* 16MB for 64k structs and each has 16 members and
 188 * a few MB spaces for the string section.
 189 * The hard limit is S32_MAX.
 190 */
 191#define BTF_MAX_SIZE (16 * 1024 * 1024)
 192
 193#define for_each_member_from(i, from, struct_type, member)		\
 194	for (i = from, member = btf_type_member(struct_type) + from;	\
 195	     i < btf_type_vlen(struct_type);				\
 196	     i++, member++)
 197
 198#define for_each_vsi_from(i, from, struct_type, member)				\
 199	for (i = from, member = btf_type_var_secinfo(struct_type) + from;	\
 200	     i < btf_type_vlen(struct_type);					\
 201	     i++, member++)
 202
 203DEFINE_IDR(btf_idr);
 204DEFINE_SPINLOCK(btf_idr_lock);
 205
 206enum btf_kfunc_hook {
 207	BTF_KFUNC_HOOK_COMMON,
 208	BTF_KFUNC_HOOK_XDP,
 209	BTF_KFUNC_HOOK_TC,
 210	BTF_KFUNC_HOOK_STRUCT_OPS,
 211	BTF_KFUNC_HOOK_TRACING,
 212	BTF_KFUNC_HOOK_SYSCALL,
 213	BTF_KFUNC_HOOK_FMODRET,
 214	BTF_KFUNC_HOOK_CGROUP_SKB,
 215	BTF_KFUNC_HOOK_SCHED_ACT,
 216	BTF_KFUNC_HOOK_SK_SKB,
 217	BTF_KFUNC_HOOK_SOCKET_FILTER,
 218	BTF_KFUNC_HOOK_LWT,
 219	BTF_KFUNC_HOOK_NETFILTER,
 220	BTF_KFUNC_HOOK_MAX,
 221};
 222
 223enum {
 224	BTF_KFUNC_SET_MAX_CNT = 256,
 225	BTF_DTOR_KFUNC_MAX_CNT = 256,
 226	BTF_KFUNC_FILTER_MAX_CNT = 16,
 227};
 228
 229struct btf_kfunc_hook_filter {
 230	btf_kfunc_filter_t filters[BTF_KFUNC_FILTER_MAX_CNT];
 231	u32 nr_filters;
 232};
 233
 234struct btf_kfunc_set_tab {
 235	struct btf_id_set8 *sets[BTF_KFUNC_HOOK_MAX];
 236	struct btf_kfunc_hook_filter hook_filters[BTF_KFUNC_HOOK_MAX];
 237};
 238
 239struct btf_id_dtor_kfunc_tab {
 240	u32 cnt;
 241	struct btf_id_dtor_kfunc dtors[];
 242};
 243
 244struct btf {
 245	void *data;
 246	struct btf_type **types;
 247	u32 *resolved_ids;
 248	u32 *resolved_sizes;
 249	const char *strings;
 250	void *nohdr_data;
 251	struct btf_header hdr;
 252	u32 nr_types; /* includes VOID for base BTF */
 253	u32 types_size;
 254	u32 data_size;
 255	refcount_t refcnt;
 256	u32 id;
 257	struct rcu_head rcu;
 258	struct btf_kfunc_set_tab *kfunc_set_tab;
 259	struct btf_id_dtor_kfunc_tab *dtor_kfunc_tab;
 260	struct btf_struct_metas *struct_meta_tab;
 261
 262	/* split BTF support */
 263	struct btf *base_btf;
 264	u32 start_id; /* first type ID in this BTF (0 for base BTF) */
 265	u32 start_str_off; /* first string offset (0 for base BTF) */
 266	char name[MODULE_NAME_LEN];
 267	bool kernel_btf;
 268};
 269
 270enum verifier_phase {
 271	CHECK_META,
 272	CHECK_TYPE,
 273};
 274
 275struct resolve_vertex {
 276	const struct btf_type *t;
 277	u32 type_id;
 278	u16 next_member;
 279};
 280
 281enum visit_state {
 282	NOT_VISITED,
 283	VISITED,
 284	RESOLVED,
 285};
 286
 287enum resolve_mode {
 288	RESOLVE_TBD,	/* To Be Determined */
 289	RESOLVE_PTR,	/* Resolving for Pointer */
 290	RESOLVE_STRUCT_OR_ARRAY,	/* Resolving for struct/union
 291					 * or array
 292					 */
 293};
 294
 295#define MAX_RESOLVE_DEPTH 32
 296
 297struct btf_sec_info {
 298	u32 off;
 299	u32 len;
 300};
 301
 302struct btf_verifier_env {
 303	struct btf *btf;
 304	u8 *visit_states;
 305	struct resolve_vertex stack[MAX_RESOLVE_DEPTH];
 306	struct bpf_verifier_log log;
 307	u32 log_type_id;
 308	u32 top_stack;
 309	enum verifier_phase phase;
 310	enum resolve_mode resolve_mode;
 311};
 312
 313static const char * const btf_kind_str[NR_BTF_KINDS] = {
 314	[BTF_KIND_UNKN]		= "UNKNOWN",
 315	[BTF_KIND_INT]		= "INT",
 316	[BTF_KIND_PTR]		= "PTR",
 317	[BTF_KIND_ARRAY]	= "ARRAY",
 318	[BTF_KIND_STRUCT]	= "STRUCT",
 319	[BTF_KIND_UNION]	= "UNION",
 320	[BTF_KIND_ENUM]		= "ENUM",
 321	[BTF_KIND_FWD]		= "FWD",
 322	[BTF_KIND_TYPEDEF]	= "TYPEDEF",
 323	[BTF_KIND_VOLATILE]	= "VOLATILE",
 324	[BTF_KIND_CONST]	= "CONST",
 325	[BTF_KIND_RESTRICT]	= "RESTRICT",
 326	[BTF_KIND_FUNC]		= "FUNC",
 327	[BTF_KIND_FUNC_PROTO]	= "FUNC_PROTO",
 328	[BTF_KIND_VAR]		= "VAR",
 329	[BTF_KIND_DATASEC]	= "DATASEC",
 330	[BTF_KIND_FLOAT]	= "FLOAT",
 331	[BTF_KIND_DECL_TAG]	= "DECL_TAG",
 332	[BTF_KIND_TYPE_TAG]	= "TYPE_TAG",
 333	[BTF_KIND_ENUM64]	= "ENUM64",
 334};
 335
 336const char *btf_type_str(const struct btf_type *t)
 337{
 338	return btf_kind_str[BTF_INFO_KIND(t->info)];
 339}
 340
 341/* Chunk size we use in safe copy of data to be shown. */
 342#define BTF_SHOW_OBJ_SAFE_SIZE		32
 343
 344/*
 345 * This is the maximum size of a base type value (equivalent to a
 346 * 128-bit int); if we are at the end of our safe buffer and have
 347 * less than 16 bytes space we can't be assured of being able
 348 * to copy the next type safely, so in such cases we will initiate
 349 * a new copy.
 350 */
 351#define BTF_SHOW_OBJ_BASE_TYPE_SIZE	16
 352
 353/* Type name size */
 354#define BTF_SHOW_NAME_SIZE		80
 355
 356/*
 357 * The suffix of a type that indicates it cannot alias another type when
 358 * comparing BTF IDs for kfunc invocations.
 359 */
 360#define NOCAST_ALIAS_SUFFIX		"___init"
 361
 362/*
 363 * Common data to all BTF show operations. Private show functions can add
 364 * their own data to a structure containing a struct btf_show and consult it
 365 * in the show callback.  See btf_type_show() below.
 366 *
 367 * One challenge with showing nested data is we want to skip 0-valued
 368 * data, but in order to figure out whether a nested object is all zeros
 369 * we need to walk through it.  As a result, we need to make two passes
 370 * when handling structs, unions and arrays; the first path simply looks
 371 * for nonzero data, while the second actually does the display.  The first
 372 * pass is signalled by show->state.depth_check being set, and if we
 373 * encounter a non-zero value we set show->state.depth_to_show to
 374 * the depth at which we encountered it.  When we have completed the
 375 * first pass, we will know if anything needs to be displayed if
 376 * depth_to_show > depth.  See btf_[struct,array]_show() for the
 377 * implementation of this.
 378 *
 379 * Another problem is we want to ensure the data for display is safe to
 380 * access.  To support this, the anonymous "struct {} obj" tracks the data
 381 * object and our safe copy of it.  We copy portions of the data needed
 382 * to the object "copy" buffer, but because its size is limited to
 383 * BTF_SHOW_OBJ_COPY_LEN bytes, multiple copies may be required as we
 384 * traverse larger objects for display.
 385 *
 386 * The various data type show functions all start with a call to
 387 * btf_show_start_type() which returns a pointer to the safe copy
 388 * of the data needed (or if BTF_SHOW_UNSAFE is specified, to the
 389 * raw data itself).  btf_show_obj_safe() is responsible for
 390 * using copy_from_kernel_nofault() to update the safe data if necessary
 391 * as we traverse the object's data.  skbuff-like semantics are
 392 * used:
 393 *
 394 * - obj.head points to the start of the toplevel object for display
 395 * - obj.size is the size of the toplevel object
 396 * - obj.data points to the current point in the original data at
 397 *   which our safe data starts.  obj.data will advance as we copy
 398 *   portions of the data.
 399 *
 400 * In most cases a single copy will suffice, but larger data structures
 401 * such as "struct task_struct" will require many copies.  The logic in
 402 * btf_show_obj_safe() handles the logic that determines if a new
 403 * copy_from_kernel_nofault() is needed.
 404 */
 405struct btf_show {
 406	u64 flags;
 407	void *target;	/* target of show operation (seq file, buffer) */
 408	void (*showfn)(struct btf_show *show, const char *fmt, va_list args);
 409	const struct btf *btf;
 410	/* below are used during iteration */
 411	struct {
 412		u8 depth;
 413		u8 depth_to_show;
 414		u8 depth_check;
 415		u8 array_member:1,
 416		   array_terminated:1;
 417		u16 array_encoding;
 418		u32 type_id;
 419		int status;			/* non-zero for error */
 420		const struct btf_type *type;
 421		const struct btf_member *member;
 422		char name[BTF_SHOW_NAME_SIZE];	/* space for member name/type */
 423	} state;
 424	struct {
 425		u32 size;
 426		void *head;
 427		void *data;
 428		u8 safe[BTF_SHOW_OBJ_SAFE_SIZE];
 429	} obj;
 430};
 431
 432struct btf_kind_operations {
 433	s32 (*check_meta)(struct btf_verifier_env *env,
 434			  const struct btf_type *t,
 435			  u32 meta_left);
 436	int (*resolve)(struct btf_verifier_env *env,
 437		       const struct resolve_vertex *v);
 438	int (*check_member)(struct btf_verifier_env *env,
 439			    const struct btf_type *struct_type,
 440			    const struct btf_member *member,
 441			    const struct btf_type *member_type);
 442	int (*check_kflag_member)(struct btf_verifier_env *env,
 443				  const struct btf_type *struct_type,
 444				  const struct btf_member *member,
 445				  const struct btf_type *member_type);
 446	void (*log_details)(struct btf_verifier_env *env,
 447			    const struct btf_type *t);
 448	void (*show)(const struct btf *btf, const struct btf_type *t,
 449			 u32 type_id, void *data, u8 bits_offsets,
 450			 struct btf_show *show);
 451};
 452
 453static const struct btf_kind_operations * const kind_ops[NR_BTF_KINDS];
 454static struct btf_type btf_void;
 455
 456static int btf_resolve(struct btf_verifier_env *env,
 457		       const struct btf_type *t, u32 type_id);
 458
 459static int btf_func_check(struct btf_verifier_env *env,
 460			  const struct btf_type *t);
 461
 462static bool btf_type_is_modifier(const struct btf_type *t)
 463{
 464	/* Some of them is not strictly a C modifier
 465	 * but they are grouped into the same bucket
 466	 * for BTF concern:
 467	 *   A type (t) that refers to another
 468	 *   type through t->type AND its size cannot
 469	 *   be determined without following the t->type.
 470	 *
 471	 * ptr does not fall into this bucket
 472	 * because its size is always sizeof(void *).
 473	 */
 474	switch (BTF_INFO_KIND(t->info)) {
 475	case BTF_KIND_TYPEDEF:
 476	case BTF_KIND_VOLATILE:
 477	case BTF_KIND_CONST:
 478	case BTF_KIND_RESTRICT:
 479	case BTF_KIND_TYPE_TAG:
 480		return true;
 481	}
 482
 483	return false;
 484}
 485
 486bool btf_type_is_void(const struct btf_type *t)
 487{
 488	return t == &btf_void;
 489}
 490
 491static bool btf_type_is_fwd(const struct btf_type *t)
 492{
 493	return BTF_INFO_KIND(t->info) == BTF_KIND_FWD;
 494}
 495
 496static bool btf_type_is_datasec(const struct btf_type *t)
 497{
 498	return BTF_INFO_KIND(t->info) == BTF_KIND_DATASEC;
 
 499}
 500
 501static bool btf_type_is_decl_tag(const struct btf_type *t)
 502{
 503	return BTF_INFO_KIND(t->info) == BTF_KIND_DECL_TAG;
 504}
 505
 506static bool btf_type_nosize(const struct btf_type *t)
 507{
 508	return btf_type_is_void(t) || btf_type_is_fwd(t) ||
 509	       btf_type_is_func(t) || btf_type_is_func_proto(t) ||
 510	       btf_type_is_decl_tag(t);
 511}
 512
 513static bool btf_type_nosize_or_null(const struct btf_type *t)
 514{
 515	return !t || btf_type_nosize(t);
 516}
 517
 518static bool btf_type_is_decl_tag_target(const struct btf_type *t)
 519{
 520	return btf_type_is_func(t) || btf_type_is_struct(t) ||
 521	       btf_type_is_var(t) || btf_type_is_typedef(t);
 522}
 523
 524u32 btf_nr_types(const struct btf *btf)
 525{
 526	u32 total = 0;
 527
 528	while (btf) {
 529		total += btf->nr_types;
 530		btf = btf->base_btf;
 531	}
 532
 533	return total;
 534}
 535
 536s32 btf_find_by_name_kind(const struct btf *btf, const char *name, u8 kind)
 537{
 538	const struct btf_type *t;
 539	const char *tname;
 540	u32 i, total;
 541
 542	total = btf_nr_types(btf);
 543	for (i = 1; i < total; i++) {
 544		t = btf_type_by_id(btf, i);
 545		if (BTF_INFO_KIND(t->info) != kind)
 546			continue;
 547
 548		tname = btf_name_by_offset(btf, t->name_off);
 549		if (!strcmp(tname, name))
 550			return i;
 551	}
 552
 553	return -ENOENT;
 554}
 555
 556s32 bpf_find_btf_id(const char *name, u32 kind, struct btf **btf_p)
 557{
 558	struct btf *btf;
 559	s32 ret;
 560	int id;
 561
 562	btf = bpf_get_btf_vmlinux();
 563	if (IS_ERR(btf))
 564		return PTR_ERR(btf);
 565	if (!btf)
 566		return -EINVAL;
 567
 568	ret = btf_find_by_name_kind(btf, name, kind);
 569	/* ret is never zero, since btf_find_by_name_kind returns
 570	 * positive btf_id or negative error.
 571	 */
 572	if (ret > 0) {
 573		btf_get(btf);
 574		*btf_p = btf;
 575		return ret;
 576	}
 577
 578	/* If name is not found in vmlinux's BTF then search in module's BTFs */
 579	spin_lock_bh(&btf_idr_lock);
 580	idr_for_each_entry(&btf_idr, btf, id) {
 581		if (!btf_is_module(btf))
 582			continue;
 583		/* linear search could be slow hence unlock/lock
 584		 * the IDR to avoiding holding it for too long
 585		 */
 586		btf_get(btf);
 587		spin_unlock_bh(&btf_idr_lock);
 588		ret = btf_find_by_name_kind(btf, name, kind);
 589		if (ret > 0) {
 590			*btf_p = btf;
 591			return ret;
 592		}
 593		btf_put(btf);
 594		spin_lock_bh(&btf_idr_lock);
 595	}
 596	spin_unlock_bh(&btf_idr_lock);
 597	return ret;
 598}
 599
 600const struct btf_type *btf_type_skip_modifiers(const struct btf *btf,
 601					       u32 id, u32 *res_id)
 602{
 603	const struct btf_type *t = btf_type_by_id(btf, id);
 604
 605	while (btf_type_is_modifier(t)) {
 606		id = t->type;
 607		t = btf_type_by_id(btf, t->type);
 608	}
 609
 610	if (res_id)
 611		*res_id = id;
 612
 613	return t;
 614}
 615
 616const struct btf_type *btf_type_resolve_ptr(const struct btf *btf,
 617					    u32 id, u32 *res_id)
 618{
 619	const struct btf_type *t;
 620
 621	t = btf_type_skip_modifiers(btf, id, NULL);
 622	if (!btf_type_is_ptr(t))
 623		return NULL;
 624
 625	return btf_type_skip_modifiers(btf, t->type, res_id);
 626}
 627
 628const struct btf_type *btf_type_resolve_func_ptr(const struct btf *btf,
 629						 u32 id, u32 *res_id)
 630{
 631	const struct btf_type *ptype;
 632
 633	ptype = btf_type_resolve_ptr(btf, id, res_id);
 634	if (ptype && btf_type_is_func_proto(ptype))
 635		return ptype;
 636
 637	return NULL;
 638}
 639
 640/* Types that act only as a source, not sink or intermediate
 641 * type when resolving.
 642 */
 643static bool btf_type_is_resolve_source_only(const struct btf_type *t)
 644{
 645	return btf_type_is_var(t) ||
 646	       btf_type_is_decl_tag(t) ||
 647	       btf_type_is_datasec(t);
 648}
 649
 650/* What types need to be resolved?
 651 *
 652 * btf_type_is_modifier() is an obvious one.
 653 *
 654 * btf_type_is_struct() because its member refers to
 655 * another type (through member->type).
 656 *
 657 * btf_type_is_var() because the variable refers to
 658 * another type. btf_type_is_datasec() holds multiple
 659 * btf_type_is_var() types that need resolving.
 660 *
 661 * btf_type_is_array() because its element (array->type)
 662 * refers to another type.  Array can be thought of a
 663 * special case of struct while array just has the same
 664 * member-type repeated by array->nelems of times.
 665 */
 666static bool btf_type_needs_resolve(const struct btf_type *t)
 667{
 668	return btf_type_is_modifier(t) ||
 669	       btf_type_is_ptr(t) ||
 670	       btf_type_is_struct(t) ||
 671	       btf_type_is_array(t) ||
 672	       btf_type_is_var(t) ||
 673	       btf_type_is_func(t) ||
 674	       btf_type_is_decl_tag(t) ||
 675	       btf_type_is_datasec(t);
 676}
 677
 678/* t->size can be used */
 679static bool btf_type_has_size(const struct btf_type *t)
 680{
 681	switch (BTF_INFO_KIND(t->info)) {
 682	case BTF_KIND_INT:
 683	case BTF_KIND_STRUCT:
 684	case BTF_KIND_UNION:
 685	case BTF_KIND_ENUM:
 686	case BTF_KIND_DATASEC:
 687	case BTF_KIND_FLOAT:
 688	case BTF_KIND_ENUM64:
 689		return true;
 690	}
 691
 692	return false;
 693}
 694
 695static const char *btf_int_encoding_str(u8 encoding)
 696{
 697	if (encoding == 0)
 698		return "(none)";
 699	else if (encoding == BTF_INT_SIGNED)
 700		return "SIGNED";
 701	else if (encoding == BTF_INT_CHAR)
 702		return "CHAR";
 703	else if (encoding == BTF_INT_BOOL)
 704		return "BOOL";
 705	else
 706		return "UNKN";
 707}
 708
 709static u32 btf_type_int(const struct btf_type *t)
 710{
 711	return *(u32 *)(t + 1);
 712}
 713
 714static const struct btf_array *btf_type_array(const struct btf_type *t)
 715{
 716	return (const struct btf_array *)(t + 1);
 717}
 718
 719static const struct btf_enum *btf_type_enum(const struct btf_type *t)
 720{
 721	return (const struct btf_enum *)(t + 1);
 722}
 723
 724static const struct btf_var *btf_type_var(const struct btf_type *t)
 725{
 726	return (const struct btf_var *)(t + 1);
 727}
 728
 729static const struct btf_decl_tag *btf_type_decl_tag(const struct btf_type *t)
 730{
 731	return (const struct btf_decl_tag *)(t + 1);
 732}
 733
 734static const struct btf_enum64 *btf_type_enum64(const struct btf_type *t)
 735{
 736	return (const struct btf_enum64 *)(t + 1);
 737}
 738
 739static const struct btf_kind_operations *btf_type_ops(const struct btf_type *t)
 740{
 741	return kind_ops[BTF_INFO_KIND(t->info)];
 742}
 743
 744static bool btf_name_offset_valid(const struct btf *btf, u32 offset)
 745{
 746	if (!BTF_STR_OFFSET_VALID(offset))
 747		return false;
 748
 749	while (offset < btf->start_str_off)
 750		btf = btf->base_btf;
 751
 752	offset -= btf->start_str_off;
 753	return offset < btf->hdr.str_len;
 754}
 755
 756static bool __btf_name_char_ok(char c, bool first)
 757{
 758	if ((first ? !isalpha(c) :
 759		     !isalnum(c)) &&
 760	    c != '_' &&
 761	    c != '.')
 
 762		return false;
 763	return true;
 764}
 765
 766static const char *btf_str_by_offset(const struct btf *btf, u32 offset)
 767{
 768	while (offset < btf->start_str_off)
 769		btf = btf->base_btf;
 770
 771	offset -= btf->start_str_off;
 772	if (offset < btf->hdr.str_len)
 773		return &btf->strings[offset];
 774
 775	return NULL;
 776}
 777
 778static bool __btf_name_valid(const struct btf *btf, u32 offset)
 779{
 780	/* offset must be valid */
 781	const char *src = btf_str_by_offset(btf, offset);
 782	const char *src_limit;
 783
 784	if (!__btf_name_char_ok(*src, true))
 785		return false;
 786
 787	/* set a limit on identifier length */
 788	src_limit = src + KSYM_NAME_LEN;
 789	src++;
 790	while (*src && src < src_limit) {
 791		if (!__btf_name_char_ok(*src, false))
 792			return false;
 793		src++;
 794	}
 795
 796	return !*src;
 797}
 798
 
 
 
 799static bool btf_name_valid_identifier(const struct btf *btf, u32 offset)
 800{
 801	return __btf_name_valid(btf, offset);
 802}
 803
 804static bool btf_name_valid_section(const struct btf *btf, u32 offset)
 805{
 806	return __btf_name_valid(btf, offset);
 807}
 808
 809static const char *__btf_name_by_offset(const struct btf *btf, u32 offset)
 810{
 811	const char *name;
 812
 813	if (!offset)
 814		return "(anon)";
 815
 816	name = btf_str_by_offset(btf, offset);
 817	return name ?: "(invalid-name-offset)";
 818}
 819
 820const char *btf_name_by_offset(const struct btf *btf, u32 offset)
 821{
 822	return btf_str_by_offset(btf, offset);
 823}
 824
 825const struct btf_type *btf_type_by_id(const struct btf *btf, u32 type_id)
 826{
 827	while (type_id < btf->start_id)
 828		btf = btf->base_btf;
 829
 830	type_id -= btf->start_id;
 831	if (type_id >= btf->nr_types)
 832		return NULL;
 833	return btf->types[type_id];
 834}
 835EXPORT_SYMBOL_GPL(btf_type_by_id);
 836
 837/*
 838 * Regular int is not a bit field and it must be either
 839 * u8/u16/u32/u64 or __int128.
 840 */
 841static bool btf_type_int_is_regular(const struct btf_type *t)
 842{
 843	u8 nr_bits, nr_bytes;
 844	u32 int_data;
 845
 846	int_data = btf_type_int(t);
 847	nr_bits = BTF_INT_BITS(int_data);
 848	nr_bytes = BITS_ROUNDUP_BYTES(nr_bits);
 849	if (BITS_PER_BYTE_MASKED(nr_bits) ||
 850	    BTF_INT_OFFSET(int_data) ||
 851	    (nr_bytes != sizeof(u8) && nr_bytes != sizeof(u16) &&
 852	     nr_bytes != sizeof(u32) && nr_bytes != sizeof(u64) &&
 853	     nr_bytes != (2 * sizeof(u64)))) {
 854		return false;
 855	}
 856
 857	return true;
 858}
 859
 860/*
 861 * Check that given struct member is a regular int with expected
 862 * offset and size.
 863 */
 864bool btf_member_is_reg_int(const struct btf *btf, const struct btf_type *s,
 865			   const struct btf_member *m,
 866			   u32 expected_offset, u32 expected_size)
 867{
 868	const struct btf_type *t;
 869	u32 id, int_data;
 870	u8 nr_bits;
 871
 872	id = m->type;
 873	t = btf_type_id_size(btf, &id, NULL);
 874	if (!t || !btf_type_is_int(t))
 875		return false;
 876
 877	int_data = btf_type_int(t);
 878	nr_bits = BTF_INT_BITS(int_data);
 879	if (btf_type_kflag(s)) {
 880		u32 bitfield_size = BTF_MEMBER_BITFIELD_SIZE(m->offset);
 881		u32 bit_offset = BTF_MEMBER_BIT_OFFSET(m->offset);
 882
 883		/* if kflag set, int should be a regular int and
 884		 * bit offset should be at byte boundary.
 885		 */
 886		return !bitfield_size &&
 887		       BITS_ROUNDUP_BYTES(bit_offset) == expected_offset &&
 888		       BITS_ROUNDUP_BYTES(nr_bits) == expected_size;
 889	}
 890
 891	if (BTF_INT_OFFSET(int_data) ||
 892	    BITS_PER_BYTE_MASKED(m->offset) ||
 893	    BITS_ROUNDUP_BYTES(m->offset) != expected_offset ||
 894	    BITS_PER_BYTE_MASKED(nr_bits) ||
 895	    BITS_ROUNDUP_BYTES(nr_bits) != expected_size)
 896		return false;
 897
 898	return true;
 899}
 900
 901/* Similar to btf_type_skip_modifiers() but does not skip typedefs. */
 902static const struct btf_type *btf_type_skip_qualifiers(const struct btf *btf,
 903						       u32 id)
 904{
 905	const struct btf_type *t = btf_type_by_id(btf, id);
 906
 907	while (btf_type_is_modifier(t) &&
 908	       BTF_INFO_KIND(t->info) != BTF_KIND_TYPEDEF) {
 909		t = btf_type_by_id(btf, t->type);
 910	}
 911
 912	return t;
 913}
 914
 915#define BTF_SHOW_MAX_ITER	10
 916
 917#define BTF_KIND_BIT(kind)	(1ULL << kind)
 918
 919/*
 920 * Populate show->state.name with type name information.
 921 * Format of type name is
 922 *
 923 * [.member_name = ] (type_name)
 924 */
 925static const char *btf_show_name(struct btf_show *show)
 926{
 927	/* BTF_MAX_ITER array suffixes "[]" */
 928	const char *array_suffixes = "[][][][][][][][][][]";
 929	const char *array_suffix = &array_suffixes[strlen(array_suffixes)];
 930	/* BTF_MAX_ITER pointer suffixes "*" */
 931	const char *ptr_suffixes = "**********";
 932	const char *ptr_suffix = &ptr_suffixes[strlen(ptr_suffixes)];
 933	const char *name = NULL, *prefix = "", *parens = "";
 934	const struct btf_member *m = show->state.member;
 935	const struct btf_type *t;
 936	const struct btf_array *array;
 937	u32 id = show->state.type_id;
 938	const char *member = NULL;
 939	bool show_member = false;
 940	u64 kinds = 0;
 941	int i;
 942
 943	show->state.name[0] = '\0';
 944
 945	/*
 946	 * Don't show type name if we're showing an array member;
 947	 * in that case we show the array type so don't need to repeat
 948	 * ourselves for each member.
 949	 */
 950	if (show->state.array_member)
 951		return "";
 952
 953	/* Retrieve member name, if any. */
 954	if (m) {
 955		member = btf_name_by_offset(show->btf, m->name_off);
 956		show_member = strlen(member) > 0;
 957		id = m->type;
 958	}
 959
 960	/*
 961	 * Start with type_id, as we have resolved the struct btf_type *
 962	 * via btf_modifier_show() past the parent typedef to the child
 963	 * struct, int etc it is defined as.  In such cases, the type_id
 964	 * still represents the starting type while the struct btf_type *
 965	 * in our show->state points at the resolved type of the typedef.
 966	 */
 967	t = btf_type_by_id(show->btf, id);
 968	if (!t)
 969		return "";
 970
 971	/*
 972	 * The goal here is to build up the right number of pointer and
 973	 * array suffixes while ensuring the type name for a typedef
 974	 * is represented.  Along the way we accumulate a list of
 975	 * BTF kinds we have encountered, since these will inform later
 976	 * display; for example, pointer types will not require an
 977	 * opening "{" for struct, we will just display the pointer value.
 978	 *
 979	 * We also want to accumulate the right number of pointer or array
 980	 * indices in the format string while iterating until we get to
 981	 * the typedef/pointee/array member target type.
 982	 *
 983	 * We start by pointing at the end of pointer and array suffix
 984	 * strings; as we accumulate pointers and arrays we move the pointer
 985	 * or array string backwards so it will show the expected number of
 986	 * '*' or '[]' for the type.  BTF_SHOW_MAX_ITER of nesting of pointers
 987	 * and/or arrays and typedefs are supported as a precaution.
 988	 *
 989	 * We also want to get typedef name while proceeding to resolve
 990	 * type it points to so that we can add parentheses if it is a
 991	 * "typedef struct" etc.
 992	 */
 993	for (i = 0; i < BTF_SHOW_MAX_ITER; i++) {
 994
 995		switch (BTF_INFO_KIND(t->info)) {
 996		case BTF_KIND_TYPEDEF:
 997			if (!name)
 998				name = btf_name_by_offset(show->btf,
 999							       t->name_off);
1000			kinds |= BTF_KIND_BIT(BTF_KIND_TYPEDEF);
1001			id = t->type;
1002			break;
1003		case BTF_KIND_ARRAY:
1004			kinds |= BTF_KIND_BIT(BTF_KIND_ARRAY);
1005			parens = "[";
1006			if (!t)
1007				return "";
1008			array = btf_type_array(t);
1009			if (array_suffix > array_suffixes)
1010				array_suffix -= 2;
1011			id = array->type;
1012			break;
1013		case BTF_KIND_PTR:
1014			kinds |= BTF_KIND_BIT(BTF_KIND_PTR);
1015			if (ptr_suffix > ptr_suffixes)
1016				ptr_suffix -= 1;
1017			id = t->type;
1018			break;
1019		default:
1020			id = 0;
1021			break;
1022		}
1023		if (!id)
1024			break;
1025		t = btf_type_skip_qualifiers(show->btf, id);
1026	}
1027	/* We may not be able to represent this type; bail to be safe */
1028	if (i == BTF_SHOW_MAX_ITER)
1029		return "";
1030
1031	if (!name)
1032		name = btf_name_by_offset(show->btf, t->name_off);
1033
1034	switch (BTF_INFO_KIND(t->info)) {
1035	case BTF_KIND_STRUCT:
1036	case BTF_KIND_UNION:
1037		prefix = BTF_INFO_KIND(t->info) == BTF_KIND_STRUCT ?
1038			 "struct" : "union";
1039		/* if it's an array of struct/union, parens is already set */
1040		if (!(kinds & (BTF_KIND_BIT(BTF_KIND_ARRAY))))
1041			parens = "{";
1042		break;
1043	case BTF_KIND_ENUM:
1044	case BTF_KIND_ENUM64:
1045		prefix = "enum";
1046		break;
1047	default:
1048		break;
1049	}
1050
1051	/* pointer does not require parens */
1052	if (kinds & BTF_KIND_BIT(BTF_KIND_PTR))
1053		parens = "";
1054	/* typedef does not require struct/union/enum prefix */
1055	if (kinds & BTF_KIND_BIT(BTF_KIND_TYPEDEF))
1056		prefix = "";
1057
1058	if (!name)
1059		name = "";
1060
1061	/* Even if we don't want type name info, we want parentheses etc */
1062	if (show->flags & BTF_SHOW_NONAME)
1063		snprintf(show->state.name, sizeof(show->state.name), "%s",
1064			 parens);
1065	else
1066		snprintf(show->state.name, sizeof(show->state.name),
1067			 "%s%s%s(%s%s%s%s%s%s)%s",
1068			 /* first 3 strings comprise ".member = " */
1069			 show_member ? "." : "",
1070			 show_member ? member : "",
1071			 show_member ? " = " : "",
1072			 /* ...next is our prefix (struct, enum, etc) */
1073			 prefix,
1074			 strlen(prefix) > 0 && strlen(name) > 0 ? " " : "",
1075			 /* ...this is the type name itself */
1076			 name,
1077			 /* ...suffixed by the appropriate '*', '[]' suffixes */
1078			 strlen(ptr_suffix) > 0 ? " " : "", ptr_suffix,
1079			 array_suffix, parens);
1080
1081	return show->state.name;
1082}
1083
1084static const char *__btf_show_indent(struct btf_show *show)
1085{
1086	const char *indents = "                                ";
1087	const char *indent = &indents[strlen(indents)];
1088
1089	if ((indent - show->state.depth) >= indents)
1090		return indent - show->state.depth;
1091	return indents;
1092}
1093
1094static const char *btf_show_indent(struct btf_show *show)
1095{
1096	return show->flags & BTF_SHOW_COMPACT ? "" : __btf_show_indent(show);
1097}
1098
1099static const char *btf_show_newline(struct btf_show *show)
1100{
1101	return show->flags & BTF_SHOW_COMPACT ? "" : "\n";
1102}
1103
1104static const char *btf_show_delim(struct btf_show *show)
1105{
1106	if (show->state.depth == 0)
1107		return "";
1108
1109	if ((show->flags & BTF_SHOW_COMPACT) && show->state.type &&
1110		BTF_INFO_KIND(show->state.type->info) == BTF_KIND_UNION)
1111		return "|";
1112
1113	return ",";
1114}
1115
1116__printf(2, 3) static void btf_show(struct btf_show *show, const char *fmt, ...)
1117{
1118	va_list args;
1119
1120	if (!show->state.depth_check) {
1121		va_start(args, fmt);
1122		show->showfn(show, fmt, args);
1123		va_end(args);
1124	}
1125}
1126
1127/* Macros are used here as btf_show_type_value[s]() prepends and appends
1128 * format specifiers to the format specifier passed in; these do the work of
1129 * adding indentation, delimiters etc while the caller simply has to specify
1130 * the type value(s) in the format specifier + value(s).
1131 */
1132#define btf_show_type_value(show, fmt, value)				       \
1133	do {								       \
1134		if ((value) != (__typeof__(value))0 ||			       \
1135		    (show->flags & BTF_SHOW_ZERO) ||			       \
1136		    show->state.depth == 0) {				       \
1137			btf_show(show, "%s%s" fmt "%s%s",		       \
1138				 btf_show_indent(show),			       \
1139				 btf_show_name(show),			       \
1140				 value, btf_show_delim(show),		       \
1141				 btf_show_newline(show));		       \
1142			if (show->state.depth > show->state.depth_to_show)     \
1143				show->state.depth_to_show = show->state.depth; \
1144		}							       \
1145	} while (0)
1146
1147#define btf_show_type_values(show, fmt, ...)				       \
1148	do {								       \
1149		btf_show(show, "%s%s" fmt "%s%s", btf_show_indent(show),       \
1150			 btf_show_name(show),				       \
1151			 __VA_ARGS__, btf_show_delim(show),		       \
1152			 btf_show_newline(show));			       \
1153		if (show->state.depth > show->state.depth_to_show)	       \
1154			show->state.depth_to_show = show->state.depth;	       \
1155	} while (0)
1156
1157/* How much is left to copy to safe buffer after @data? */
1158static int btf_show_obj_size_left(struct btf_show *show, void *data)
1159{
1160	return show->obj.head + show->obj.size - data;
1161}
1162
1163/* Is object pointed to by @data of @size already copied to our safe buffer? */
1164static bool btf_show_obj_is_safe(struct btf_show *show, void *data, int size)
1165{
1166	return data >= show->obj.data &&
1167	       (data + size) < (show->obj.data + BTF_SHOW_OBJ_SAFE_SIZE);
1168}
1169
1170/*
1171 * If object pointed to by @data of @size falls within our safe buffer, return
1172 * the equivalent pointer to the same safe data.  Assumes
1173 * copy_from_kernel_nofault() has already happened and our safe buffer is
1174 * populated.
1175 */
1176static void *__btf_show_obj_safe(struct btf_show *show, void *data, int size)
1177{
1178	if (btf_show_obj_is_safe(show, data, size))
1179		return show->obj.safe + (data - show->obj.data);
1180	return NULL;
1181}
1182
1183/*
1184 * Return a safe-to-access version of data pointed to by @data.
1185 * We do this by copying the relevant amount of information
1186 * to the struct btf_show obj.safe buffer using copy_from_kernel_nofault().
1187 *
1188 * If BTF_SHOW_UNSAFE is specified, just return data as-is; no
1189 * safe copy is needed.
1190 *
1191 * Otherwise we need to determine if we have the required amount
1192 * of data (determined by the @data pointer and the size of the
1193 * largest base type we can encounter (represented by
1194 * BTF_SHOW_OBJ_BASE_TYPE_SIZE). Having that much data ensures
1195 * that we will be able to print some of the current object,
1196 * and if more is needed a copy will be triggered.
1197 * Some objects such as structs will not fit into the buffer;
1198 * in such cases additional copies when we iterate over their
1199 * members may be needed.
1200 *
1201 * btf_show_obj_safe() is used to return a safe buffer for
1202 * btf_show_start_type(); this ensures that as we recurse into
1203 * nested types we always have safe data for the given type.
1204 * This approach is somewhat wasteful; it's possible for example
1205 * that when iterating over a large union we'll end up copying the
1206 * same data repeatedly, but the goal is safety not performance.
1207 * We use stack data as opposed to per-CPU buffers because the
1208 * iteration over a type can take some time, and preemption handling
1209 * would greatly complicate use of the safe buffer.
1210 */
1211static void *btf_show_obj_safe(struct btf_show *show,
1212			       const struct btf_type *t,
1213			       void *data)
1214{
1215	const struct btf_type *rt;
1216	int size_left, size;
1217	void *safe = NULL;
1218
1219	if (show->flags & BTF_SHOW_UNSAFE)
1220		return data;
1221
1222	rt = btf_resolve_size(show->btf, t, &size);
1223	if (IS_ERR(rt)) {
1224		show->state.status = PTR_ERR(rt);
1225		return NULL;
1226	}
1227
1228	/*
1229	 * Is this toplevel object? If so, set total object size and
1230	 * initialize pointers.  Otherwise check if we still fall within
1231	 * our safe object data.
1232	 */
1233	if (show->state.depth == 0) {
1234		show->obj.size = size;
1235		show->obj.head = data;
1236	} else {
1237		/*
1238		 * If the size of the current object is > our remaining
1239		 * safe buffer we _may_ need to do a new copy.  However
1240		 * consider the case of a nested struct; it's size pushes
1241		 * us over the safe buffer limit, but showing any individual
1242		 * struct members does not.  In such cases, we don't need
1243		 * to initiate a fresh copy yet; however we definitely need
1244		 * at least BTF_SHOW_OBJ_BASE_TYPE_SIZE bytes left
1245		 * in our buffer, regardless of the current object size.
1246		 * The logic here is that as we resolve types we will
1247		 * hit a base type at some point, and we need to be sure
1248		 * the next chunk of data is safely available to display
1249		 * that type info safely.  We cannot rely on the size of
1250		 * the current object here because it may be much larger
1251		 * than our current buffer (e.g. task_struct is 8k).
1252		 * All we want to do here is ensure that we can print the
1253		 * next basic type, which we can if either
1254		 * - the current type size is within the safe buffer; or
1255		 * - at least BTF_SHOW_OBJ_BASE_TYPE_SIZE bytes are left in
1256		 *   the safe buffer.
1257		 */
1258		safe = __btf_show_obj_safe(show, data,
1259					   min(size,
1260					       BTF_SHOW_OBJ_BASE_TYPE_SIZE));
1261	}
1262
1263	/*
1264	 * We need a new copy to our safe object, either because we haven't
1265	 * yet copied and are initializing safe data, or because the data
1266	 * we want falls outside the boundaries of the safe object.
1267	 */
1268	if (!safe) {
1269		size_left = btf_show_obj_size_left(show, data);
1270		if (size_left > BTF_SHOW_OBJ_SAFE_SIZE)
1271			size_left = BTF_SHOW_OBJ_SAFE_SIZE;
1272		show->state.status = copy_from_kernel_nofault(show->obj.safe,
1273							      data, size_left);
1274		if (!show->state.status) {
1275			show->obj.data = data;
1276			safe = show->obj.safe;
1277		}
1278	}
1279
1280	return safe;
1281}
1282
1283/*
1284 * Set the type we are starting to show and return a safe data pointer
1285 * to be used for showing the associated data.
1286 */
1287static void *btf_show_start_type(struct btf_show *show,
1288				 const struct btf_type *t,
1289				 u32 type_id, void *data)
1290{
1291	show->state.type = t;
1292	show->state.type_id = type_id;
1293	show->state.name[0] = '\0';
1294
1295	return btf_show_obj_safe(show, t, data);
1296}
1297
1298static void btf_show_end_type(struct btf_show *show)
1299{
1300	show->state.type = NULL;
1301	show->state.type_id = 0;
1302	show->state.name[0] = '\0';
1303}
1304
1305static void *btf_show_start_aggr_type(struct btf_show *show,
1306				      const struct btf_type *t,
1307				      u32 type_id, void *data)
1308{
1309	void *safe_data = btf_show_start_type(show, t, type_id, data);
1310
1311	if (!safe_data)
1312		return safe_data;
1313
1314	btf_show(show, "%s%s%s", btf_show_indent(show),
1315		 btf_show_name(show),
1316		 btf_show_newline(show));
1317	show->state.depth++;
1318	return safe_data;
1319}
1320
1321static void btf_show_end_aggr_type(struct btf_show *show,
1322				   const char *suffix)
1323{
1324	show->state.depth--;
1325	btf_show(show, "%s%s%s%s", btf_show_indent(show), suffix,
1326		 btf_show_delim(show), btf_show_newline(show));
1327	btf_show_end_type(show);
1328}
1329
1330static void btf_show_start_member(struct btf_show *show,
1331				  const struct btf_member *m)
1332{
1333	show->state.member = m;
1334}
1335
1336static void btf_show_start_array_member(struct btf_show *show)
1337{
1338	show->state.array_member = 1;
1339	btf_show_start_member(show, NULL);
1340}
1341
1342static void btf_show_end_member(struct btf_show *show)
1343{
1344	show->state.member = NULL;
1345}
1346
1347static void btf_show_end_array_member(struct btf_show *show)
1348{
1349	show->state.array_member = 0;
1350	btf_show_end_member(show);
1351}
1352
1353static void *btf_show_start_array_type(struct btf_show *show,
1354				       const struct btf_type *t,
1355				       u32 type_id,
1356				       u16 array_encoding,
1357				       void *data)
1358{
1359	show->state.array_encoding = array_encoding;
1360	show->state.array_terminated = 0;
1361	return btf_show_start_aggr_type(show, t, type_id, data);
1362}
1363
1364static void btf_show_end_array_type(struct btf_show *show)
1365{
1366	show->state.array_encoding = 0;
1367	show->state.array_terminated = 0;
1368	btf_show_end_aggr_type(show, "]");
1369}
1370
1371static void *btf_show_start_struct_type(struct btf_show *show,
1372					const struct btf_type *t,
1373					u32 type_id,
1374					void *data)
1375{
1376	return btf_show_start_aggr_type(show, t, type_id, data);
1377}
1378
1379static void btf_show_end_struct_type(struct btf_show *show)
1380{
1381	btf_show_end_aggr_type(show, "}");
1382}
1383
1384__printf(2, 3) static void __btf_verifier_log(struct bpf_verifier_log *log,
1385					      const char *fmt, ...)
1386{
1387	va_list args;
1388
1389	va_start(args, fmt);
1390	bpf_verifier_vlog(log, fmt, args);
1391	va_end(args);
1392}
1393
1394__printf(2, 3) static void btf_verifier_log(struct btf_verifier_env *env,
1395					    const char *fmt, ...)
1396{
1397	struct bpf_verifier_log *log = &env->log;
1398	va_list args;
1399
1400	if (!bpf_verifier_log_needed(log))
1401		return;
1402
1403	va_start(args, fmt);
1404	bpf_verifier_vlog(log, fmt, args);
1405	va_end(args);
1406}
1407
1408__printf(4, 5) static void __btf_verifier_log_type(struct btf_verifier_env *env,
1409						   const struct btf_type *t,
1410						   bool log_details,
1411						   const char *fmt, ...)
1412{
1413	struct bpf_verifier_log *log = &env->log;
 
1414	struct btf *btf = env->btf;
1415	va_list args;
1416
1417	if (!bpf_verifier_log_needed(log))
1418		return;
1419
1420	if (log->level == BPF_LOG_KERNEL) {
1421		/* btf verifier prints all types it is processing via
1422		 * btf_verifier_log_type(..., fmt = NULL).
1423		 * Skip those prints for in-kernel BTF verification.
1424		 */
1425		if (!fmt)
1426			return;
1427
1428		/* Skip logging when loading module BTF with mismatches permitted */
1429		if (env->btf->base_btf && IS_ENABLED(CONFIG_MODULE_ALLOW_BTF_MISMATCH))
1430			return;
1431	}
1432
1433	__btf_verifier_log(log, "[%u] %s %s%s",
1434			   env->log_type_id,
1435			   btf_type_str(t),
1436			   __btf_name_by_offset(btf, t->name_off),
1437			   log_details ? " " : "");
1438
1439	if (log_details)
1440		btf_type_ops(t)->log_details(env, t);
1441
1442	if (fmt && *fmt) {
1443		__btf_verifier_log(log, " ");
1444		va_start(args, fmt);
1445		bpf_verifier_vlog(log, fmt, args);
1446		va_end(args);
1447	}
1448
1449	__btf_verifier_log(log, "\n");
1450}
1451
1452#define btf_verifier_log_type(env, t, ...) \
1453	__btf_verifier_log_type((env), (t), true, __VA_ARGS__)
1454#define btf_verifier_log_basic(env, t, ...) \
1455	__btf_verifier_log_type((env), (t), false, __VA_ARGS__)
1456
1457__printf(4, 5)
1458static void btf_verifier_log_member(struct btf_verifier_env *env,
1459				    const struct btf_type *struct_type,
1460				    const struct btf_member *member,
1461				    const char *fmt, ...)
1462{
1463	struct bpf_verifier_log *log = &env->log;
1464	struct btf *btf = env->btf;
1465	va_list args;
1466
1467	if (!bpf_verifier_log_needed(log))
1468		return;
1469
1470	if (log->level == BPF_LOG_KERNEL) {
1471		if (!fmt)
1472			return;
1473
1474		/* Skip logging when loading module BTF with mismatches permitted */
1475		if (env->btf->base_btf && IS_ENABLED(CONFIG_MODULE_ALLOW_BTF_MISMATCH))
1476			return;
1477	}
1478
1479	/* The CHECK_META phase already did a btf dump.
1480	 *
1481	 * If member is logged again, it must hit an error in
1482	 * parsing this member.  It is useful to print out which
1483	 * struct this member belongs to.
1484	 */
1485	if (env->phase != CHECK_META)
1486		btf_verifier_log_type(env, struct_type, NULL);
1487
1488	if (btf_type_kflag(struct_type))
1489		__btf_verifier_log(log,
1490				   "\t%s type_id=%u bitfield_size=%u bits_offset=%u",
1491				   __btf_name_by_offset(btf, member->name_off),
1492				   member->type,
1493				   BTF_MEMBER_BITFIELD_SIZE(member->offset),
1494				   BTF_MEMBER_BIT_OFFSET(member->offset));
1495	else
1496		__btf_verifier_log(log, "\t%s type_id=%u bits_offset=%u",
1497				   __btf_name_by_offset(btf, member->name_off),
1498				   member->type, member->offset);
1499
1500	if (fmt && *fmt) {
1501		__btf_verifier_log(log, " ");
1502		va_start(args, fmt);
1503		bpf_verifier_vlog(log, fmt, args);
1504		va_end(args);
1505	}
1506
1507	__btf_verifier_log(log, "\n");
1508}
1509
1510__printf(4, 5)
1511static void btf_verifier_log_vsi(struct btf_verifier_env *env,
1512				 const struct btf_type *datasec_type,
1513				 const struct btf_var_secinfo *vsi,
1514				 const char *fmt, ...)
1515{
1516	struct bpf_verifier_log *log = &env->log;
1517	va_list args;
1518
1519	if (!bpf_verifier_log_needed(log))
1520		return;
1521	if (log->level == BPF_LOG_KERNEL && !fmt)
1522		return;
1523	if (env->phase != CHECK_META)
1524		btf_verifier_log_type(env, datasec_type, NULL);
1525
1526	__btf_verifier_log(log, "\t type_id=%u offset=%u size=%u",
1527			   vsi->type, vsi->offset, vsi->size);
1528	if (fmt && *fmt) {
1529		__btf_verifier_log(log, " ");
1530		va_start(args, fmt);
1531		bpf_verifier_vlog(log, fmt, args);
1532		va_end(args);
1533	}
1534
1535	__btf_verifier_log(log, "\n");
1536}
1537
1538static void btf_verifier_log_hdr(struct btf_verifier_env *env,
1539				 u32 btf_data_size)
1540{
1541	struct bpf_verifier_log *log = &env->log;
1542	const struct btf *btf = env->btf;
1543	const struct btf_header *hdr;
1544
1545	if (!bpf_verifier_log_needed(log))
1546		return;
1547
1548	if (log->level == BPF_LOG_KERNEL)
1549		return;
1550	hdr = &btf->hdr;
1551	__btf_verifier_log(log, "magic: 0x%x\n", hdr->magic);
1552	__btf_verifier_log(log, "version: %u\n", hdr->version);
1553	__btf_verifier_log(log, "flags: 0x%x\n", hdr->flags);
1554	__btf_verifier_log(log, "hdr_len: %u\n", hdr->hdr_len);
1555	__btf_verifier_log(log, "type_off: %u\n", hdr->type_off);
1556	__btf_verifier_log(log, "type_len: %u\n", hdr->type_len);
1557	__btf_verifier_log(log, "str_off: %u\n", hdr->str_off);
1558	__btf_verifier_log(log, "str_len: %u\n", hdr->str_len);
1559	__btf_verifier_log(log, "btf_total_size: %u\n", btf_data_size);
1560}
1561
1562static int btf_add_type(struct btf_verifier_env *env, struct btf_type *t)
1563{
1564	struct btf *btf = env->btf;
1565
1566	if (btf->types_size == btf->nr_types) {
1567		/* Expand 'types' array */
1568
1569		struct btf_type **new_types;
1570		u32 expand_by, new_size;
1571
1572		if (btf->start_id + btf->types_size == BTF_MAX_TYPE) {
1573			btf_verifier_log(env, "Exceeded max num of types");
1574			return -E2BIG;
1575		}
1576
1577		expand_by = max_t(u32, btf->types_size >> 2, 16);
1578		new_size = min_t(u32, BTF_MAX_TYPE,
1579				 btf->types_size + expand_by);
1580
1581		new_types = kvcalloc(new_size, sizeof(*new_types),
1582				     GFP_KERNEL | __GFP_NOWARN);
1583		if (!new_types)
1584			return -ENOMEM;
1585
1586		if (btf->nr_types == 0) {
1587			if (!btf->base_btf) {
1588				/* lazily init VOID type */
1589				new_types[0] = &btf_void;
1590				btf->nr_types++;
1591			}
1592		} else {
1593			memcpy(new_types, btf->types,
1594			       sizeof(*btf->types) * btf->nr_types);
1595		}
1596
1597		kvfree(btf->types);
1598		btf->types = new_types;
1599		btf->types_size = new_size;
1600	}
1601
1602	btf->types[btf->nr_types++] = t;
1603
1604	return 0;
1605}
1606
1607static int btf_alloc_id(struct btf *btf)
1608{
1609	int id;
1610
1611	idr_preload(GFP_KERNEL);
1612	spin_lock_bh(&btf_idr_lock);
1613	id = idr_alloc_cyclic(&btf_idr, btf, 1, INT_MAX, GFP_ATOMIC);
1614	if (id > 0)
1615		btf->id = id;
1616	spin_unlock_bh(&btf_idr_lock);
1617	idr_preload_end();
1618
1619	if (WARN_ON_ONCE(!id))
1620		return -ENOSPC;
1621
1622	return id > 0 ? 0 : id;
1623}
1624
1625static void btf_free_id(struct btf *btf)
1626{
1627	unsigned long flags;
1628
1629	/*
1630	 * In map-in-map, calling map_delete_elem() on outer
1631	 * map will call bpf_map_put on the inner map.
1632	 * It will then eventually call btf_free_id()
1633	 * on the inner map.  Some of the map_delete_elem()
1634	 * implementation may have irq disabled, so
1635	 * we need to use the _irqsave() version instead
1636	 * of the _bh() version.
1637	 */
1638	spin_lock_irqsave(&btf_idr_lock, flags);
1639	idr_remove(&btf_idr, btf->id);
1640	spin_unlock_irqrestore(&btf_idr_lock, flags);
1641}
1642
1643static void btf_free_kfunc_set_tab(struct btf *btf)
1644{
1645	struct btf_kfunc_set_tab *tab = btf->kfunc_set_tab;
1646	int hook;
1647
1648	if (!tab)
1649		return;
1650	/* For module BTF, we directly assign the sets being registered, so
1651	 * there is nothing to free except kfunc_set_tab.
1652	 */
1653	if (btf_is_module(btf))
1654		goto free_tab;
1655	for (hook = 0; hook < ARRAY_SIZE(tab->sets); hook++)
1656		kfree(tab->sets[hook]);
1657free_tab:
1658	kfree(tab);
1659	btf->kfunc_set_tab = NULL;
1660}
1661
1662static void btf_free_dtor_kfunc_tab(struct btf *btf)
1663{
1664	struct btf_id_dtor_kfunc_tab *tab = btf->dtor_kfunc_tab;
1665
1666	if (!tab)
1667		return;
1668	kfree(tab);
1669	btf->dtor_kfunc_tab = NULL;
1670}
1671
1672static void btf_struct_metas_free(struct btf_struct_metas *tab)
1673{
1674	int i;
1675
1676	if (!tab)
1677		return;
1678	for (i = 0; i < tab->cnt; i++)
1679		btf_record_free(tab->types[i].record);
1680	kfree(tab);
1681}
1682
1683static void btf_free_struct_meta_tab(struct btf *btf)
1684{
1685	struct btf_struct_metas *tab = btf->struct_meta_tab;
1686
1687	btf_struct_metas_free(tab);
1688	btf->struct_meta_tab = NULL;
1689}
1690
1691static void btf_free(struct btf *btf)
1692{
1693	btf_free_struct_meta_tab(btf);
1694	btf_free_dtor_kfunc_tab(btf);
1695	btf_free_kfunc_set_tab(btf);
1696	kvfree(btf->types);
1697	kvfree(btf->resolved_sizes);
1698	kvfree(btf->resolved_ids);
1699	kvfree(btf->data);
1700	kfree(btf);
1701}
1702
1703static void btf_free_rcu(struct rcu_head *rcu)
1704{
1705	struct btf *btf = container_of(rcu, struct btf, rcu);
1706
1707	btf_free(btf);
1708}
1709
1710void btf_get(struct btf *btf)
1711{
1712	refcount_inc(&btf->refcnt);
1713}
1714
1715void btf_put(struct btf *btf)
1716{
1717	if (btf && refcount_dec_and_test(&btf->refcnt)) {
1718		btf_free_id(btf);
1719		call_rcu(&btf->rcu, btf_free_rcu);
1720	}
1721}
1722
1723static int env_resolve_init(struct btf_verifier_env *env)
1724{
1725	struct btf *btf = env->btf;
1726	u32 nr_types = btf->nr_types;
1727	u32 *resolved_sizes = NULL;
1728	u32 *resolved_ids = NULL;
1729	u8 *visit_states = NULL;
1730
1731	resolved_sizes = kvcalloc(nr_types, sizeof(*resolved_sizes),
1732				  GFP_KERNEL | __GFP_NOWARN);
1733	if (!resolved_sizes)
1734		goto nomem;
1735
1736	resolved_ids = kvcalloc(nr_types, sizeof(*resolved_ids),
1737				GFP_KERNEL | __GFP_NOWARN);
1738	if (!resolved_ids)
1739		goto nomem;
1740
1741	visit_states = kvcalloc(nr_types, sizeof(*visit_states),
1742				GFP_KERNEL | __GFP_NOWARN);
1743	if (!visit_states)
1744		goto nomem;
1745
1746	btf->resolved_sizes = resolved_sizes;
1747	btf->resolved_ids = resolved_ids;
1748	env->visit_states = visit_states;
1749
1750	return 0;
1751
1752nomem:
1753	kvfree(resolved_sizes);
1754	kvfree(resolved_ids);
1755	kvfree(visit_states);
1756	return -ENOMEM;
1757}
1758
1759static void btf_verifier_env_free(struct btf_verifier_env *env)
1760{
1761	kvfree(env->visit_states);
1762	kfree(env);
1763}
1764
1765static bool env_type_is_resolve_sink(const struct btf_verifier_env *env,
1766				     const struct btf_type *next_type)
1767{
1768	switch (env->resolve_mode) {
1769	case RESOLVE_TBD:
1770		/* int, enum or void is a sink */
1771		return !btf_type_needs_resolve(next_type);
1772	case RESOLVE_PTR:
1773		/* int, enum, void, struct, array, func or func_proto is a sink
1774		 * for ptr
1775		 */
1776		return !btf_type_is_modifier(next_type) &&
1777			!btf_type_is_ptr(next_type);
1778	case RESOLVE_STRUCT_OR_ARRAY:
1779		/* int, enum, void, ptr, func or func_proto is a sink
1780		 * for struct and array
1781		 */
1782		return !btf_type_is_modifier(next_type) &&
1783			!btf_type_is_array(next_type) &&
1784			!btf_type_is_struct(next_type);
1785	default:
1786		BUG();
1787	}
1788}
1789
1790static bool env_type_is_resolved(const struct btf_verifier_env *env,
1791				 u32 type_id)
1792{
1793	/* base BTF types should be resolved by now */
1794	if (type_id < env->btf->start_id)
1795		return true;
1796
1797	return env->visit_states[type_id - env->btf->start_id] == RESOLVED;
1798}
1799
1800static int env_stack_push(struct btf_verifier_env *env,
1801			  const struct btf_type *t, u32 type_id)
1802{
1803	const struct btf *btf = env->btf;
1804	struct resolve_vertex *v;
1805
1806	if (env->top_stack == MAX_RESOLVE_DEPTH)
1807		return -E2BIG;
1808
1809	if (type_id < btf->start_id
1810	    || env->visit_states[type_id - btf->start_id] != NOT_VISITED)
1811		return -EEXIST;
1812
1813	env->visit_states[type_id - btf->start_id] = VISITED;
1814
1815	v = &env->stack[env->top_stack++];
1816	v->t = t;
1817	v->type_id = type_id;
1818	v->next_member = 0;
1819
1820	if (env->resolve_mode == RESOLVE_TBD) {
1821		if (btf_type_is_ptr(t))
1822			env->resolve_mode = RESOLVE_PTR;
1823		else if (btf_type_is_struct(t) || btf_type_is_array(t))
1824			env->resolve_mode = RESOLVE_STRUCT_OR_ARRAY;
1825	}
1826
1827	return 0;
1828}
1829
1830static void env_stack_set_next_member(struct btf_verifier_env *env,
1831				      u16 next_member)
1832{
1833	env->stack[env->top_stack - 1].next_member = next_member;
1834}
1835
1836static void env_stack_pop_resolved(struct btf_verifier_env *env,
1837				   u32 resolved_type_id,
1838				   u32 resolved_size)
1839{
1840	u32 type_id = env->stack[--(env->top_stack)].type_id;
1841	struct btf *btf = env->btf;
1842
1843	type_id -= btf->start_id; /* adjust to local type id */
1844	btf->resolved_sizes[type_id] = resolved_size;
1845	btf->resolved_ids[type_id] = resolved_type_id;
1846	env->visit_states[type_id] = RESOLVED;
1847}
1848
1849static const struct resolve_vertex *env_stack_peak(struct btf_verifier_env *env)
1850{
1851	return env->top_stack ? &env->stack[env->top_stack - 1] : NULL;
1852}
1853
1854/* Resolve the size of a passed-in "type"
1855 *
1856 * type: is an array (e.g. u32 array[x][y])
1857 * return type: type "u32[x][y]", i.e. BTF_KIND_ARRAY,
1858 * *type_size: (x * y * sizeof(u32)).  Hence, *type_size always
1859 *             corresponds to the return type.
1860 * *elem_type: u32
1861 * *elem_id: id of u32
1862 * *total_nelems: (x * y).  Hence, individual elem size is
1863 *                (*type_size / *total_nelems)
1864 * *type_id: id of type if it's changed within the function, 0 if not
1865 *
1866 * type: is not an array (e.g. const struct X)
1867 * return type: type "struct X"
1868 * *type_size: sizeof(struct X)
1869 * *elem_type: same as return type ("struct X")
1870 * *elem_id: 0
1871 * *total_nelems: 1
1872 * *type_id: id of type if it's changed within the function, 0 if not
1873 */
1874static const struct btf_type *
1875__btf_resolve_size(const struct btf *btf, const struct btf_type *type,
1876		   u32 *type_size, const struct btf_type **elem_type,
1877		   u32 *elem_id, u32 *total_nelems, u32 *type_id)
1878{
1879	const struct btf_type *array_type = NULL;
1880	const struct btf_array *array = NULL;
1881	u32 i, size, nelems = 1, id = 0;
1882
1883	for (i = 0; i < MAX_RESOLVE_DEPTH; i++) {
1884		switch (BTF_INFO_KIND(type->info)) {
1885		/* type->size can be used */
1886		case BTF_KIND_INT:
1887		case BTF_KIND_STRUCT:
1888		case BTF_KIND_UNION:
1889		case BTF_KIND_ENUM:
1890		case BTF_KIND_FLOAT:
1891		case BTF_KIND_ENUM64:
1892			size = type->size;
1893			goto resolved;
1894
1895		case BTF_KIND_PTR:
1896			size = sizeof(void *);
1897			goto resolved;
1898
1899		/* Modifiers */
1900		case BTF_KIND_TYPEDEF:
1901		case BTF_KIND_VOLATILE:
1902		case BTF_KIND_CONST:
1903		case BTF_KIND_RESTRICT:
1904		case BTF_KIND_TYPE_TAG:
1905			id = type->type;
1906			type = btf_type_by_id(btf, type->type);
1907			break;
1908
1909		case BTF_KIND_ARRAY:
1910			if (!array_type)
1911				array_type = type;
1912			array = btf_type_array(type);
1913			if (nelems && array->nelems > U32_MAX / nelems)
1914				return ERR_PTR(-EINVAL);
1915			nelems *= array->nelems;
1916			type = btf_type_by_id(btf, array->type);
1917			break;
1918
1919		/* type without size */
1920		default:
1921			return ERR_PTR(-EINVAL);
1922		}
1923	}
1924
1925	return ERR_PTR(-EINVAL);
1926
1927resolved:
1928	if (nelems && size > U32_MAX / nelems)
1929		return ERR_PTR(-EINVAL);
1930
1931	*type_size = nelems * size;
1932	if (total_nelems)
1933		*total_nelems = nelems;
1934	if (elem_type)
1935		*elem_type = type;
1936	if (elem_id)
1937		*elem_id = array ? array->type : 0;
1938	if (type_id && id)
1939		*type_id = id;
1940
1941	return array_type ? : type;
1942}
1943
1944const struct btf_type *
1945btf_resolve_size(const struct btf *btf, const struct btf_type *type,
1946		 u32 *type_size)
1947{
1948	return __btf_resolve_size(btf, type, type_size, NULL, NULL, NULL, NULL);
1949}
1950
1951static u32 btf_resolved_type_id(const struct btf *btf, u32 type_id)
1952{
1953	while (type_id < btf->start_id)
1954		btf = btf->base_btf;
1955
1956	return btf->resolved_ids[type_id - btf->start_id];
1957}
1958
1959/* The input param "type_id" must point to a needs_resolve type */
1960static const struct btf_type *btf_type_id_resolve(const struct btf *btf,
1961						  u32 *type_id)
1962{
1963	*type_id = btf_resolved_type_id(btf, *type_id);
1964	return btf_type_by_id(btf, *type_id);
1965}
1966
1967static u32 btf_resolved_type_size(const struct btf *btf, u32 type_id)
1968{
1969	while (type_id < btf->start_id)
1970		btf = btf->base_btf;
1971
1972	return btf->resolved_sizes[type_id - btf->start_id];
1973}
1974
1975const struct btf_type *btf_type_id_size(const struct btf *btf,
1976					u32 *type_id, u32 *ret_size)
1977{
1978	const struct btf_type *size_type;
1979	u32 size_type_id = *type_id;
1980	u32 size = 0;
1981
1982	size_type = btf_type_by_id(btf, size_type_id);
1983	if (btf_type_nosize_or_null(size_type))
1984		return NULL;
1985
1986	if (btf_type_has_size(size_type)) {
1987		size = size_type->size;
1988	} else if (btf_type_is_array(size_type)) {
1989		size = btf_resolved_type_size(btf, size_type_id);
1990	} else if (btf_type_is_ptr(size_type)) {
1991		size = sizeof(void *);
1992	} else {
1993		if (WARN_ON_ONCE(!btf_type_is_modifier(size_type) &&
1994				 !btf_type_is_var(size_type)))
1995			return NULL;
1996
1997		size_type_id = btf_resolved_type_id(btf, size_type_id);
1998		size_type = btf_type_by_id(btf, size_type_id);
1999		if (btf_type_nosize_or_null(size_type))
2000			return NULL;
2001		else if (btf_type_has_size(size_type))
2002			size = size_type->size;
2003		else if (btf_type_is_array(size_type))
2004			size = btf_resolved_type_size(btf, size_type_id);
2005		else if (btf_type_is_ptr(size_type))
2006			size = sizeof(void *);
2007		else
2008			return NULL;
2009	}
2010
2011	*type_id = size_type_id;
2012	if (ret_size)
2013		*ret_size = size;
2014
2015	return size_type;
2016}
2017
2018static int btf_df_check_member(struct btf_verifier_env *env,
2019			       const struct btf_type *struct_type,
2020			       const struct btf_member *member,
2021			       const struct btf_type *member_type)
2022{
2023	btf_verifier_log_basic(env, struct_type,
2024			       "Unsupported check_member");
2025	return -EINVAL;
2026}
2027
2028static int btf_df_check_kflag_member(struct btf_verifier_env *env,
2029				     const struct btf_type *struct_type,
2030				     const struct btf_member *member,
2031				     const struct btf_type *member_type)
2032{
2033	btf_verifier_log_basic(env, struct_type,
2034			       "Unsupported check_kflag_member");
2035	return -EINVAL;
2036}
2037
2038/* Used for ptr, array struct/union and float type members.
2039 * int, enum and modifier types have their specific callback functions.
2040 */
2041static int btf_generic_check_kflag_member(struct btf_verifier_env *env,
2042					  const struct btf_type *struct_type,
2043					  const struct btf_member *member,
2044					  const struct btf_type *member_type)
2045{
2046	if (BTF_MEMBER_BITFIELD_SIZE(member->offset)) {
2047		btf_verifier_log_member(env, struct_type, member,
2048					"Invalid member bitfield_size");
2049		return -EINVAL;
2050	}
2051
2052	/* bitfield size is 0, so member->offset represents bit offset only.
2053	 * It is safe to call non kflag check_member variants.
2054	 */
2055	return btf_type_ops(member_type)->check_member(env, struct_type,
2056						       member,
2057						       member_type);
2058}
2059
2060static int btf_df_resolve(struct btf_verifier_env *env,
2061			  const struct resolve_vertex *v)
2062{
2063	btf_verifier_log_basic(env, v->t, "Unsupported resolve");
2064	return -EINVAL;
2065}
2066
2067static void btf_df_show(const struct btf *btf, const struct btf_type *t,
2068			u32 type_id, void *data, u8 bits_offsets,
2069			struct btf_show *show)
2070{
2071	btf_show(show, "<unsupported kind:%u>", BTF_INFO_KIND(t->info));
2072}
2073
2074static int btf_int_check_member(struct btf_verifier_env *env,
2075				const struct btf_type *struct_type,
2076				const struct btf_member *member,
2077				const struct btf_type *member_type)
2078{
2079	u32 int_data = btf_type_int(member_type);
2080	u32 struct_bits_off = member->offset;
2081	u32 struct_size = struct_type->size;
2082	u32 nr_copy_bits;
2083	u32 bytes_offset;
2084
2085	if (U32_MAX - struct_bits_off < BTF_INT_OFFSET(int_data)) {
2086		btf_verifier_log_member(env, struct_type, member,
2087					"bits_offset exceeds U32_MAX");
2088		return -EINVAL;
2089	}
2090
2091	struct_bits_off += BTF_INT_OFFSET(int_data);
2092	bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2093	nr_copy_bits = BTF_INT_BITS(int_data) +
2094		BITS_PER_BYTE_MASKED(struct_bits_off);
2095
2096	if (nr_copy_bits > BITS_PER_U128) {
2097		btf_verifier_log_member(env, struct_type, member,
2098					"nr_copy_bits exceeds 128");
2099		return -EINVAL;
2100	}
2101
2102	if (struct_size < bytes_offset ||
2103	    struct_size - bytes_offset < BITS_ROUNDUP_BYTES(nr_copy_bits)) {
2104		btf_verifier_log_member(env, struct_type, member,
2105					"Member exceeds struct_size");
2106		return -EINVAL;
2107	}
2108
2109	return 0;
2110}
2111
2112static int btf_int_check_kflag_member(struct btf_verifier_env *env,
2113				      const struct btf_type *struct_type,
2114				      const struct btf_member *member,
2115				      const struct btf_type *member_type)
2116{
2117	u32 struct_bits_off, nr_bits, nr_int_data_bits, bytes_offset;
2118	u32 int_data = btf_type_int(member_type);
2119	u32 struct_size = struct_type->size;
2120	u32 nr_copy_bits;
2121
2122	/* a regular int type is required for the kflag int member */
2123	if (!btf_type_int_is_regular(member_type)) {
2124		btf_verifier_log_member(env, struct_type, member,
2125					"Invalid member base type");
2126		return -EINVAL;
2127	}
2128
2129	/* check sanity of bitfield size */
2130	nr_bits = BTF_MEMBER_BITFIELD_SIZE(member->offset);
2131	struct_bits_off = BTF_MEMBER_BIT_OFFSET(member->offset);
2132	nr_int_data_bits = BTF_INT_BITS(int_data);
2133	if (!nr_bits) {
2134		/* Not a bitfield member, member offset must be at byte
2135		 * boundary.
2136		 */
2137		if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
2138			btf_verifier_log_member(env, struct_type, member,
2139						"Invalid member offset");
2140			return -EINVAL;
2141		}
2142
2143		nr_bits = nr_int_data_bits;
2144	} else if (nr_bits > nr_int_data_bits) {
2145		btf_verifier_log_member(env, struct_type, member,
2146					"Invalid member bitfield_size");
2147		return -EINVAL;
2148	}
2149
2150	bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2151	nr_copy_bits = nr_bits + BITS_PER_BYTE_MASKED(struct_bits_off);
2152	if (nr_copy_bits > BITS_PER_U128) {
2153		btf_verifier_log_member(env, struct_type, member,
2154					"nr_copy_bits exceeds 128");
2155		return -EINVAL;
2156	}
2157
2158	if (struct_size < bytes_offset ||
2159	    struct_size - bytes_offset < BITS_ROUNDUP_BYTES(nr_copy_bits)) {
2160		btf_verifier_log_member(env, struct_type, member,
2161					"Member exceeds struct_size");
2162		return -EINVAL;
2163	}
2164
2165	return 0;
2166}
2167
2168static s32 btf_int_check_meta(struct btf_verifier_env *env,
2169			      const struct btf_type *t,
2170			      u32 meta_left)
2171{
2172	u32 int_data, nr_bits, meta_needed = sizeof(int_data);
2173	u16 encoding;
2174
2175	if (meta_left < meta_needed) {
2176		btf_verifier_log_basic(env, t,
2177				       "meta_left:%u meta_needed:%u",
2178				       meta_left, meta_needed);
2179		return -EINVAL;
2180	}
2181
2182	if (btf_type_vlen(t)) {
2183		btf_verifier_log_type(env, t, "vlen != 0");
2184		return -EINVAL;
2185	}
2186
2187	if (btf_type_kflag(t)) {
2188		btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
2189		return -EINVAL;
2190	}
2191
2192	int_data = btf_type_int(t);
2193	if (int_data & ~BTF_INT_MASK) {
2194		btf_verifier_log_basic(env, t, "Invalid int_data:%x",
2195				       int_data);
2196		return -EINVAL;
2197	}
2198
2199	nr_bits = BTF_INT_BITS(int_data) + BTF_INT_OFFSET(int_data);
2200
2201	if (nr_bits > BITS_PER_U128) {
2202		btf_verifier_log_type(env, t, "nr_bits exceeds %zu",
2203				      BITS_PER_U128);
2204		return -EINVAL;
2205	}
2206
2207	if (BITS_ROUNDUP_BYTES(nr_bits) > t->size) {
2208		btf_verifier_log_type(env, t, "nr_bits exceeds type_size");
2209		return -EINVAL;
2210	}
2211
2212	/*
2213	 * Only one of the encoding bits is allowed and it
2214	 * should be sufficient for the pretty print purpose (i.e. decoding).
2215	 * Multiple bits can be allowed later if it is found
2216	 * to be insufficient.
2217	 */
2218	encoding = BTF_INT_ENCODING(int_data);
2219	if (encoding &&
2220	    encoding != BTF_INT_SIGNED &&
2221	    encoding != BTF_INT_CHAR &&
2222	    encoding != BTF_INT_BOOL) {
2223		btf_verifier_log_type(env, t, "Unsupported encoding");
2224		return -ENOTSUPP;
2225	}
2226
2227	btf_verifier_log_type(env, t, NULL);
2228
2229	return meta_needed;
2230}
2231
2232static void btf_int_log(struct btf_verifier_env *env,
2233			const struct btf_type *t)
2234{
2235	int int_data = btf_type_int(t);
2236
2237	btf_verifier_log(env,
2238			 "size=%u bits_offset=%u nr_bits=%u encoding=%s",
2239			 t->size, BTF_INT_OFFSET(int_data),
2240			 BTF_INT_BITS(int_data),
2241			 btf_int_encoding_str(BTF_INT_ENCODING(int_data)));
2242}
2243
2244static void btf_int128_print(struct btf_show *show, void *data)
2245{
2246	/* data points to a __int128 number.
2247	 * Suppose
2248	 *     int128_num = *(__int128 *)data;
2249	 * The below formulas shows what upper_num and lower_num represents:
2250	 *     upper_num = int128_num >> 64;
2251	 *     lower_num = int128_num & 0xffffffffFFFFFFFFULL;
2252	 */
2253	u64 upper_num, lower_num;
2254
2255#ifdef __BIG_ENDIAN_BITFIELD
2256	upper_num = *(u64 *)data;
2257	lower_num = *(u64 *)(data + 8);
2258#else
2259	upper_num = *(u64 *)(data + 8);
2260	lower_num = *(u64 *)data;
2261#endif
2262	if (upper_num == 0)
2263		btf_show_type_value(show, "0x%llx", lower_num);
2264	else
2265		btf_show_type_values(show, "0x%llx%016llx", upper_num,
2266				     lower_num);
2267}
2268
2269static void btf_int128_shift(u64 *print_num, u16 left_shift_bits,
2270			     u16 right_shift_bits)
2271{
2272	u64 upper_num, lower_num;
2273
2274#ifdef __BIG_ENDIAN_BITFIELD
2275	upper_num = print_num[0];
2276	lower_num = print_num[1];
2277#else
2278	upper_num = print_num[1];
2279	lower_num = print_num[0];
2280#endif
2281
2282	/* shake out un-needed bits by shift/or operations */
2283	if (left_shift_bits >= 64) {
2284		upper_num = lower_num << (left_shift_bits - 64);
2285		lower_num = 0;
2286	} else {
2287		upper_num = (upper_num << left_shift_bits) |
2288			    (lower_num >> (64 - left_shift_bits));
2289		lower_num = lower_num << left_shift_bits;
2290	}
2291
2292	if (right_shift_bits >= 64) {
2293		lower_num = upper_num >> (right_shift_bits - 64);
2294		upper_num = 0;
2295	} else {
2296		lower_num = (lower_num >> right_shift_bits) |
2297			    (upper_num << (64 - right_shift_bits));
2298		upper_num = upper_num >> right_shift_bits;
2299	}
2300
2301#ifdef __BIG_ENDIAN_BITFIELD
2302	print_num[0] = upper_num;
2303	print_num[1] = lower_num;
2304#else
2305	print_num[0] = lower_num;
2306	print_num[1] = upper_num;
2307#endif
2308}
2309
2310static void btf_bitfield_show(void *data, u8 bits_offset,
2311			      u8 nr_bits, struct btf_show *show)
2312{
2313	u16 left_shift_bits, right_shift_bits;
2314	u8 nr_copy_bytes;
2315	u8 nr_copy_bits;
2316	u64 print_num[2] = {};
2317
2318	nr_copy_bits = nr_bits + bits_offset;
2319	nr_copy_bytes = BITS_ROUNDUP_BYTES(nr_copy_bits);
2320
2321	memcpy(print_num, data, nr_copy_bytes);
2322
2323#ifdef __BIG_ENDIAN_BITFIELD
2324	left_shift_bits = bits_offset;
2325#else
2326	left_shift_bits = BITS_PER_U128 - nr_copy_bits;
2327#endif
2328	right_shift_bits = BITS_PER_U128 - nr_bits;
2329
2330	btf_int128_shift(print_num, left_shift_bits, right_shift_bits);
2331	btf_int128_print(show, print_num);
2332}
2333
2334
2335static void btf_int_bits_show(const struct btf *btf,
2336			      const struct btf_type *t,
2337			      void *data, u8 bits_offset,
2338			      struct btf_show *show)
2339{
2340	u32 int_data = btf_type_int(t);
2341	u8 nr_bits = BTF_INT_BITS(int_data);
2342	u8 total_bits_offset;
2343
2344	/*
2345	 * bits_offset is at most 7.
2346	 * BTF_INT_OFFSET() cannot exceed 128 bits.
2347	 */
2348	total_bits_offset = bits_offset + BTF_INT_OFFSET(int_data);
2349	data += BITS_ROUNDDOWN_BYTES(total_bits_offset);
2350	bits_offset = BITS_PER_BYTE_MASKED(total_bits_offset);
2351	btf_bitfield_show(data, bits_offset, nr_bits, show);
2352}
2353
2354static void btf_int_show(const struct btf *btf, const struct btf_type *t,
2355			 u32 type_id, void *data, u8 bits_offset,
2356			 struct btf_show *show)
2357{
2358	u32 int_data = btf_type_int(t);
2359	u8 encoding = BTF_INT_ENCODING(int_data);
2360	bool sign = encoding & BTF_INT_SIGNED;
2361	u8 nr_bits = BTF_INT_BITS(int_data);
2362	void *safe_data;
2363
2364	safe_data = btf_show_start_type(show, t, type_id, data);
2365	if (!safe_data)
2366		return;
2367
2368	if (bits_offset || BTF_INT_OFFSET(int_data) ||
2369	    BITS_PER_BYTE_MASKED(nr_bits)) {
2370		btf_int_bits_show(btf, t, safe_data, bits_offset, show);
2371		goto out;
2372	}
2373
2374	switch (nr_bits) {
2375	case 128:
2376		btf_int128_print(show, safe_data);
2377		break;
2378	case 64:
2379		if (sign)
2380			btf_show_type_value(show, "%lld", *(s64 *)safe_data);
2381		else
2382			btf_show_type_value(show, "%llu", *(u64 *)safe_data);
2383		break;
2384	case 32:
2385		if (sign)
2386			btf_show_type_value(show, "%d", *(s32 *)safe_data);
2387		else
2388			btf_show_type_value(show, "%u", *(u32 *)safe_data);
2389		break;
2390	case 16:
2391		if (sign)
2392			btf_show_type_value(show, "%d", *(s16 *)safe_data);
2393		else
2394			btf_show_type_value(show, "%u", *(u16 *)safe_data);
2395		break;
2396	case 8:
2397		if (show->state.array_encoding == BTF_INT_CHAR) {
2398			/* check for null terminator */
2399			if (show->state.array_terminated)
2400				break;
2401			if (*(char *)data == '\0') {
2402				show->state.array_terminated = 1;
2403				break;
2404			}
2405			if (isprint(*(char *)data)) {
2406				btf_show_type_value(show, "'%c'",
2407						    *(char *)safe_data);
2408				break;
2409			}
2410		}
2411		if (sign)
2412			btf_show_type_value(show, "%d", *(s8 *)safe_data);
2413		else
2414			btf_show_type_value(show, "%u", *(u8 *)safe_data);
2415		break;
2416	default:
2417		btf_int_bits_show(btf, t, safe_data, bits_offset, show);
2418		break;
2419	}
2420out:
2421	btf_show_end_type(show);
2422}
2423
2424static const struct btf_kind_operations int_ops = {
2425	.check_meta = btf_int_check_meta,
2426	.resolve = btf_df_resolve,
2427	.check_member = btf_int_check_member,
2428	.check_kflag_member = btf_int_check_kflag_member,
2429	.log_details = btf_int_log,
2430	.show = btf_int_show,
2431};
2432
2433static int btf_modifier_check_member(struct btf_verifier_env *env,
2434				     const struct btf_type *struct_type,
2435				     const struct btf_member *member,
2436				     const struct btf_type *member_type)
2437{
2438	const struct btf_type *resolved_type;
2439	u32 resolved_type_id = member->type;
2440	struct btf_member resolved_member;
2441	struct btf *btf = env->btf;
2442
2443	resolved_type = btf_type_id_size(btf, &resolved_type_id, NULL);
2444	if (!resolved_type) {
2445		btf_verifier_log_member(env, struct_type, member,
2446					"Invalid member");
2447		return -EINVAL;
2448	}
2449
2450	resolved_member = *member;
2451	resolved_member.type = resolved_type_id;
2452
2453	return btf_type_ops(resolved_type)->check_member(env, struct_type,
2454							 &resolved_member,
2455							 resolved_type);
2456}
2457
2458static int btf_modifier_check_kflag_member(struct btf_verifier_env *env,
2459					   const struct btf_type *struct_type,
2460					   const struct btf_member *member,
2461					   const struct btf_type *member_type)
2462{
2463	const struct btf_type *resolved_type;
2464	u32 resolved_type_id = member->type;
2465	struct btf_member resolved_member;
2466	struct btf *btf = env->btf;
2467
2468	resolved_type = btf_type_id_size(btf, &resolved_type_id, NULL);
2469	if (!resolved_type) {
2470		btf_verifier_log_member(env, struct_type, member,
2471					"Invalid member");
2472		return -EINVAL;
2473	}
2474
2475	resolved_member = *member;
2476	resolved_member.type = resolved_type_id;
2477
2478	return btf_type_ops(resolved_type)->check_kflag_member(env, struct_type,
2479							       &resolved_member,
2480							       resolved_type);
2481}
2482
2483static int btf_ptr_check_member(struct btf_verifier_env *env,
2484				const struct btf_type *struct_type,
2485				const struct btf_member *member,
2486				const struct btf_type *member_type)
2487{
2488	u32 struct_size, struct_bits_off, bytes_offset;
2489
2490	struct_size = struct_type->size;
2491	struct_bits_off = member->offset;
2492	bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2493
2494	if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
2495		btf_verifier_log_member(env, struct_type, member,
2496					"Member is not byte aligned");
2497		return -EINVAL;
2498	}
2499
2500	if (struct_size - bytes_offset < sizeof(void *)) {
2501		btf_verifier_log_member(env, struct_type, member,
2502					"Member exceeds struct_size");
2503		return -EINVAL;
2504	}
2505
2506	return 0;
2507}
2508
2509static int btf_ref_type_check_meta(struct btf_verifier_env *env,
2510				   const struct btf_type *t,
2511				   u32 meta_left)
2512{
2513	const char *value;
2514
2515	if (btf_type_vlen(t)) {
2516		btf_verifier_log_type(env, t, "vlen != 0");
2517		return -EINVAL;
2518	}
2519
2520	if (btf_type_kflag(t)) {
2521		btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
2522		return -EINVAL;
2523	}
2524
2525	if (!BTF_TYPE_ID_VALID(t->type)) {
2526		btf_verifier_log_type(env, t, "Invalid type_id");
2527		return -EINVAL;
2528	}
2529
2530	/* typedef/type_tag type must have a valid name, and other ref types,
2531	 * volatile, const, restrict, should have a null name.
2532	 */
2533	if (BTF_INFO_KIND(t->info) == BTF_KIND_TYPEDEF) {
2534		if (!t->name_off ||
2535		    !btf_name_valid_identifier(env->btf, t->name_off)) {
2536			btf_verifier_log_type(env, t, "Invalid name");
2537			return -EINVAL;
2538		}
2539	} else if (BTF_INFO_KIND(t->info) == BTF_KIND_TYPE_TAG) {
2540		value = btf_name_by_offset(env->btf, t->name_off);
2541		if (!value || !value[0]) {
2542			btf_verifier_log_type(env, t, "Invalid name");
2543			return -EINVAL;
2544		}
2545	} else {
2546		if (t->name_off) {
2547			btf_verifier_log_type(env, t, "Invalid name");
2548			return -EINVAL;
2549		}
2550	}
2551
2552	btf_verifier_log_type(env, t, NULL);
2553
2554	return 0;
2555}
2556
2557static int btf_modifier_resolve(struct btf_verifier_env *env,
2558				const struct resolve_vertex *v)
2559{
2560	const struct btf_type *t = v->t;
2561	const struct btf_type *next_type;
2562	u32 next_type_id = t->type;
2563	struct btf *btf = env->btf;
2564
2565	next_type = btf_type_by_id(btf, next_type_id);
2566	if (!next_type || btf_type_is_resolve_source_only(next_type)) {
2567		btf_verifier_log_type(env, v->t, "Invalid type_id");
2568		return -EINVAL;
2569	}
2570
2571	if (!env_type_is_resolve_sink(env, next_type) &&
2572	    !env_type_is_resolved(env, next_type_id))
2573		return env_stack_push(env, next_type, next_type_id);
2574
2575	/* Figure out the resolved next_type_id with size.
2576	 * They will be stored in the current modifier's
2577	 * resolved_ids and resolved_sizes such that it can
2578	 * save us a few type-following when we use it later (e.g. in
2579	 * pretty print).
2580	 */
2581	if (!btf_type_id_size(btf, &next_type_id, NULL)) {
2582		if (env_type_is_resolved(env, next_type_id))
2583			next_type = btf_type_id_resolve(btf, &next_type_id);
2584
2585		/* "typedef void new_void", "const void"...etc */
2586		if (!btf_type_is_void(next_type) &&
2587		    !btf_type_is_fwd(next_type) &&
2588		    !btf_type_is_func_proto(next_type)) {
2589			btf_verifier_log_type(env, v->t, "Invalid type_id");
2590			return -EINVAL;
2591		}
2592	}
2593
2594	env_stack_pop_resolved(env, next_type_id, 0);
2595
2596	return 0;
2597}
2598
2599static int btf_var_resolve(struct btf_verifier_env *env,
2600			   const struct resolve_vertex *v)
2601{
2602	const struct btf_type *next_type;
2603	const struct btf_type *t = v->t;
2604	u32 next_type_id = t->type;
2605	struct btf *btf = env->btf;
2606
2607	next_type = btf_type_by_id(btf, next_type_id);
2608	if (!next_type || btf_type_is_resolve_source_only(next_type)) {
2609		btf_verifier_log_type(env, v->t, "Invalid type_id");
2610		return -EINVAL;
2611	}
2612
2613	if (!env_type_is_resolve_sink(env, next_type) &&
2614	    !env_type_is_resolved(env, next_type_id))
2615		return env_stack_push(env, next_type, next_type_id);
2616
2617	if (btf_type_is_modifier(next_type)) {
2618		const struct btf_type *resolved_type;
2619		u32 resolved_type_id;
2620
2621		resolved_type_id = next_type_id;
2622		resolved_type = btf_type_id_resolve(btf, &resolved_type_id);
2623
2624		if (btf_type_is_ptr(resolved_type) &&
2625		    !env_type_is_resolve_sink(env, resolved_type) &&
2626		    !env_type_is_resolved(env, resolved_type_id))
2627			return env_stack_push(env, resolved_type,
2628					      resolved_type_id);
2629	}
2630
2631	/* We must resolve to something concrete at this point, no
2632	 * forward types or similar that would resolve to size of
2633	 * zero is allowed.
2634	 */
2635	if (!btf_type_id_size(btf, &next_type_id, NULL)) {
2636		btf_verifier_log_type(env, v->t, "Invalid type_id");
2637		return -EINVAL;
2638	}
2639
2640	env_stack_pop_resolved(env, next_type_id, 0);
2641
2642	return 0;
2643}
2644
2645static int btf_ptr_resolve(struct btf_verifier_env *env,
2646			   const struct resolve_vertex *v)
2647{
2648	const struct btf_type *next_type;
2649	const struct btf_type *t = v->t;
2650	u32 next_type_id = t->type;
2651	struct btf *btf = env->btf;
2652
2653	next_type = btf_type_by_id(btf, next_type_id);
2654	if (!next_type || btf_type_is_resolve_source_only(next_type)) {
2655		btf_verifier_log_type(env, v->t, "Invalid type_id");
2656		return -EINVAL;
2657	}
2658
2659	if (!env_type_is_resolve_sink(env, next_type) &&
2660	    !env_type_is_resolved(env, next_type_id))
2661		return env_stack_push(env, next_type, next_type_id);
2662
2663	/* If the modifier was RESOLVED during RESOLVE_STRUCT_OR_ARRAY,
2664	 * the modifier may have stopped resolving when it was resolved
2665	 * to a ptr (last-resolved-ptr).
2666	 *
2667	 * We now need to continue from the last-resolved-ptr to
2668	 * ensure the last-resolved-ptr will not referring back to
2669	 * the current ptr (t).
2670	 */
2671	if (btf_type_is_modifier(next_type)) {
2672		const struct btf_type *resolved_type;
2673		u32 resolved_type_id;
2674
2675		resolved_type_id = next_type_id;
2676		resolved_type = btf_type_id_resolve(btf, &resolved_type_id);
2677
2678		if (btf_type_is_ptr(resolved_type) &&
2679		    !env_type_is_resolve_sink(env, resolved_type) &&
2680		    !env_type_is_resolved(env, resolved_type_id))
2681			return env_stack_push(env, resolved_type,
2682					      resolved_type_id);
2683	}
2684
2685	if (!btf_type_id_size(btf, &next_type_id, NULL)) {
2686		if (env_type_is_resolved(env, next_type_id))
2687			next_type = btf_type_id_resolve(btf, &next_type_id);
2688
2689		if (!btf_type_is_void(next_type) &&
2690		    !btf_type_is_fwd(next_type) &&
2691		    !btf_type_is_func_proto(next_type)) {
2692			btf_verifier_log_type(env, v->t, "Invalid type_id");
2693			return -EINVAL;
2694		}
2695	}
2696
2697	env_stack_pop_resolved(env, next_type_id, 0);
2698
2699	return 0;
2700}
2701
2702static void btf_modifier_show(const struct btf *btf,
2703			      const struct btf_type *t,
2704			      u32 type_id, void *data,
2705			      u8 bits_offset, struct btf_show *show)
2706{
2707	if (btf->resolved_ids)
2708		t = btf_type_id_resolve(btf, &type_id);
2709	else
2710		t = btf_type_skip_modifiers(btf, type_id, NULL);
2711
2712	btf_type_ops(t)->show(btf, t, type_id, data, bits_offset, show);
2713}
2714
2715static void btf_var_show(const struct btf *btf, const struct btf_type *t,
2716			 u32 type_id, void *data, u8 bits_offset,
2717			 struct btf_show *show)
2718{
2719	t = btf_type_id_resolve(btf, &type_id);
2720
2721	btf_type_ops(t)->show(btf, t, type_id, data, bits_offset, show);
2722}
2723
2724static void btf_ptr_show(const struct btf *btf, const struct btf_type *t,
2725			 u32 type_id, void *data, u8 bits_offset,
2726			 struct btf_show *show)
2727{
2728	void *safe_data;
2729
2730	safe_data = btf_show_start_type(show, t, type_id, data);
2731	if (!safe_data)
2732		return;
2733
2734	/* It is a hashed value unless BTF_SHOW_PTR_RAW is specified */
2735	if (show->flags & BTF_SHOW_PTR_RAW)
2736		btf_show_type_value(show, "0x%px", *(void **)safe_data);
2737	else
2738		btf_show_type_value(show, "0x%p", *(void **)safe_data);
2739	btf_show_end_type(show);
2740}
2741
2742static void btf_ref_type_log(struct btf_verifier_env *env,
2743			     const struct btf_type *t)
2744{
2745	btf_verifier_log(env, "type_id=%u", t->type);
2746}
2747
2748static struct btf_kind_operations modifier_ops = {
2749	.check_meta = btf_ref_type_check_meta,
2750	.resolve = btf_modifier_resolve,
2751	.check_member = btf_modifier_check_member,
2752	.check_kflag_member = btf_modifier_check_kflag_member,
2753	.log_details = btf_ref_type_log,
2754	.show = btf_modifier_show,
2755};
2756
2757static struct btf_kind_operations ptr_ops = {
2758	.check_meta = btf_ref_type_check_meta,
2759	.resolve = btf_ptr_resolve,
2760	.check_member = btf_ptr_check_member,
2761	.check_kflag_member = btf_generic_check_kflag_member,
2762	.log_details = btf_ref_type_log,
2763	.show = btf_ptr_show,
2764};
2765
2766static s32 btf_fwd_check_meta(struct btf_verifier_env *env,
2767			      const struct btf_type *t,
2768			      u32 meta_left)
2769{
2770	if (btf_type_vlen(t)) {
2771		btf_verifier_log_type(env, t, "vlen != 0");
2772		return -EINVAL;
2773	}
2774
2775	if (t->type) {
2776		btf_verifier_log_type(env, t, "type != 0");
2777		return -EINVAL;
2778	}
2779
2780	/* fwd type must have a valid name */
2781	if (!t->name_off ||
2782	    !btf_name_valid_identifier(env->btf, t->name_off)) {
2783		btf_verifier_log_type(env, t, "Invalid name");
2784		return -EINVAL;
2785	}
2786
2787	btf_verifier_log_type(env, t, NULL);
2788
2789	return 0;
2790}
2791
2792static void btf_fwd_type_log(struct btf_verifier_env *env,
2793			     const struct btf_type *t)
2794{
2795	btf_verifier_log(env, "%s", btf_type_kflag(t) ? "union" : "struct");
2796}
2797
2798static struct btf_kind_operations fwd_ops = {
2799	.check_meta = btf_fwd_check_meta,
2800	.resolve = btf_df_resolve,
2801	.check_member = btf_df_check_member,
2802	.check_kflag_member = btf_df_check_kflag_member,
2803	.log_details = btf_fwd_type_log,
2804	.show = btf_df_show,
2805};
2806
2807static int btf_array_check_member(struct btf_verifier_env *env,
2808				  const struct btf_type *struct_type,
2809				  const struct btf_member *member,
2810				  const struct btf_type *member_type)
2811{
2812	u32 struct_bits_off = member->offset;
2813	u32 struct_size, bytes_offset;
2814	u32 array_type_id, array_size;
2815	struct btf *btf = env->btf;
2816
2817	if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
2818		btf_verifier_log_member(env, struct_type, member,
2819					"Member is not byte aligned");
2820		return -EINVAL;
2821	}
2822
2823	array_type_id = member->type;
2824	btf_type_id_size(btf, &array_type_id, &array_size);
2825	struct_size = struct_type->size;
2826	bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2827	if (struct_size - bytes_offset < array_size) {
2828		btf_verifier_log_member(env, struct_type, member,
2829					"Member exceeds struct_size");
2830		return -EINVAL;
2831	}
2832
2833	return 0;
2834}
2835
2836static s32 btf_array_check_meta(struct btf_verifier_env *env,
2837				const struct btf_type *t,
2838				u32 meta_left)
2839{
2840	const struct btf_array *array = btf_type_array(t);
2841	u32 meta_needed = sizeof(*array);
2842
2843	if (meta_left < meta_needed) {
2844		btf_verifier_log_basic(env, t,
2845				       "meta_left:%u meta_needed:%u",
2846				       meta_left, meta_needed);
2847		return -EINVAL;
2848	}
2849
2850	/* array type should not have a name */
2851	if (t->name_off) {
2852		btf_verifier_log_type(env, t, "Invalid name");
2853		return -EINVAL;
2854	}
2855
2856	if (btf_type_vlen(t)) {
2857		btf_verifier_log_type(env, t, "vlen != 0");
2858		return -EINVAL;
2859	}
2860
2861	if (btf_type_kflag(t)) {
2862		btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
2863		return -EINVAL;
2864	}
2865
2866	if (t->size) {
2867		btf_verifier_log_type(env, t, "size != 0");
2868		return -EINVAL;
2869	}
2870
2871	/* Array elem type and index type cannot be in type void,
2872	 * so !array->type and !array->index_type are not allowed.
2873	 */
2874	if (!array->type || !BTF_TYPE_ID_VALID(array->type)) {
2875		btf_verifier_log_type(env, t, "Invalid elem");
2876		return -EINVAL;
2877	}
2878
2879	if (!array->index_type || !BTF_TYPE_ID_VALID(array->index_type)) {
2880		btf_verifier_log_type(env, t, "Invalid index");
2881		return -EINVAL;
2882	}
2883
2884	btf_verifier_log_type(env, t, NULL);
2885
2886	return meta_needed;
2887}
2888
2889static int btf_array_resolve(struct btf_verifier_env *env,
2890			     const struct resolve_vertex *v)
2891{
2892	const struct btf_array *array = btf_type_array(v->t);
2893	const struct btf_type *elem_type, *index_type;
2894	u32 elem_type_id, index_type_id;
2895	struct btf *btf = env->btf;
2896	u32 elem_size;
2897
2898	/* Check array->index_type */
2899	index_type_id = array->index_type;
2900	index_type = btf_type_by_id(btf, index_type_id);
2901	if (btf_type_nosize_or_null(index_type) ||
2902	    btf_type_is_resolve_source_only(index_type)) {
2903		btf_verifier_log_type(env, v->t, "Invalid index");
2904		return -EINVAL;
2905	}
2906
2907	if (!env_type_is_resolve_sink(env, index_type) &&
2908	    !env_type_is_resolved(env, index_type_id))
2909		return env_stack_push(env, index_type, index_type_id);
2910
2911	index_type = btf_type_id_size(btf, &index_type_id, NULL);
2912	if (!index_type || !btf_type_is_int(index_type) ||
2913	    !btf_type_int_is_regular(index_type)) {
2914		btf_verifier_log_type(env, v->t, "Invalid index");
2915		return -EINVAL;
2916	}
2917
2918	/* Check array->type */
2919	elem_type_id = array->type;
2920	elem_type = btf_type_by_id(btf, elem_type_id);
2921	if (btf_type_nosize_or_null(elem_type) ||
2922	    btf_type_is_resolve_source_only(elem_type)) {
2923		btf_verifier_log_type(env, v->t,
2924				      "Invalid elem");
2925		return -EINVAL;
2926	}
2927
2928	if (!env_type_is_resolve_sink(env, elem_type) &&
2929	    !env_type_is_resolved(env, elem_type_id))
2930		return env_stack_push(env, elem_type, elem_type_id);
2931
2932	elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size);
2933	if (!elem_type) {
2934		btf_verifier_log_type(env, v->t, "Invalid elem");
2935		return -EINVAL;
2936	}
2937
2938	if (btf_type_is_int(elem_type) && !btf_type_int_is_regular(elem_type)) {
2939		btf_verifier_log_type(env, v->t, "Invalid array of int");
2940		return -EINVAL;
2941	}
2942
2943	if (array->nelems && elem_size > U32_MAX / array->nelems) {
2944		btf_verifier_log_type(env, v->t,
2945				      "Array size overflows U32_MAX");
2946		return -EINVAL;
2947	}
2948
2949	env_stack_pop_resolved(env, elem_type_id, elem_size * array->nelems);
2950
2951	return 0;
2952}
2953
2954static void btf_array_log(struct btf_verifier_env *env,
2955			  const struct btf_type *t)
2956{
2957	const struct btf_array *array = btf_type_array(t);
2958
2959	btf_verifier_log(env, "type_id=%u index_type_id=%u nr_elems=%u",
2960			 array->type, array->index_type, array->nelems);
2961}
2962
2963static void __btf_array_show(const struct btf *btf, const struct btf_type *t,
2964			     u32 type_id, void *data, u8 bits_offset,
2965			     struct btf_show *show)
2966{
2967	const struct btf_array *array = btf_type_array(t);
2968	const struct btf_kind_operations *elem_ops;
2969	const struct btf_type *elem_type;
2970	u32 i, elem_size = 0, elem_type_id;
2971	u16 encoding = 0;
2972
2973	elem_type_id = array->type;
2974	elem_type = btf_type_skip_modifiers(btf, elem_type_id, NULL);
2975	if (elem_type && btf_type_has_size(elem_type))
2976		elem_size = elem_type->size;
2977
2978	if (elem_type && btf_type_is_int(elem_type)) {
2979		u32 int_type = btf_type_int(elem_type);
2980
2981		encoding = BTF_INT_ENCODING(int_type);
2982
2983		/*
2984		 * BTF_INT_CHAR encoding never seems to be set for
2985		 * char arrays, so if size is 1 and element is
2986		 * printable as a char, we'll do that.
2987		 */
2988		if (elem_size == 1)
2989			encoding = BTF_INT_CHAR;
2990	}
2991
2992	if (!btf_show_start_array_type(show, t, type_id, encoding, data))
2993		return;
2994
2995	if (!elem_type)
2996		goto out;
2997	elem_ops = btf_type_ops(elem_type);
2998
2999	for (i = 0; i < array->nelems; i++) {
3000
3001		btf_show_start_array_member(show);
3002
3003		elem_ops->show(btf, elem_type, elem_type_id, data,
3004			       bits_offset, show);
3005		data += elem_size;
3006
3007		btf_show_end_array_member(show);
3008
3009		if (show->state.array_terminated)
3010			break;
3011	}
3012out:
3013	btf_show_end_array_type(show);
3014}
3015
3016static void btf_array_show(const struct btf *btf, const struct btf_type *t,
3017			   u32 type_id, void *data, u8 bits_offset,
3018			   struct btf_show *show)
3019{
3020	const struct btf_member *m = show->state.member;
3021
3022	/*
3023	 * First check if any members would be shown (are non-zero).
3024	 * See comments above "struct btf_show" definition for more
3025	 * details on how this works at a high-level.
3026	 */
3027	if (show->state.depth > 0 && !(show->flags & BTF_SHOW_ZERO)) {
3028		if (!show->state.depth_check) {
3029			show->state.depth_check = show->state.depth + 1;
3030			show->state.depth_to_show = 0;
3031		}
3032		__btf_array_show(btf, t, type_id, data, bits_offset, show);
3033		show->state.member = m;
3034
3035		if (show->state.depth_check != show->state.depth + 1)
3036			return;
3037		show->state.depth_check = 0;
3038
3039		if (show->state.depth_to_show <= show->state.depth)
3040			return;
3041		/*
3042		 * Reaching here indicates we have recursed and found
3043		 * non-zero array member(s).
3044		 */
3045	}
3046	__btf_array_show(btf, t, type_id, data, bits_offset, show);
3047}
3048
3049static struct btf_kind_operations array_ops = {
3050	.check_meta = btf_array_check_meta,
3051	.resolve = btf_array_resolve,
3052	.check_member = btf_array_check_member,
3053	.check_kflag_member = btf_generic_check_kflag_member,
3054	.log_details = btf_array_log,
3055	.show = btf_array_show,
3056};
3057
3058static int btf_struct_check_member(struct btf_verifier_env *env,
3059				   const struct btf_type *struct_type,
3060				   const struct btf_member *member,
3061				   const struct btf_type *member_type)
3062{
3063	u32 struct_bits_off = member->offset;
3064	u32 struct_size, bytes_offset;
3065
3066	if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
3067		btf_verifier_log_member(env, struct_type, member,
3068					"Member is not byte aligned");
3069		return -EINVAL;
3070	}
3071
3072	struct_size = struct_type->size;
3073	bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
3074	if (struct_size - bytes_offset < member_type->size) {
3075		btf_verifier_log_member(env, struct_type, member,
3076					"Member exceeds struct_size");
3077		return -EINVAL;
3078	}
3079
3080	return 0;
3081}
3082
3083static s32 btf_struct_check_meta(struct btf_verifier_env *env,
3084				 const struct btf_type *t,
3085				 u32 meta_left)
3086{
3087	bool is_union = BTF_INFO_KIND(t->info) == BTF_KIND_UNION;
3088	const struct btf_member *member;
3089	u32 meta_needed, last_offset;
3090	struct btf *btf = env->btf;
3091	u32 struct_size = t->size;
3092	u32 offset;
3093	u16 i;
3094
3095	meta_needed = btf_type_vlen(t) * sizeof(*member);
3096	if (meta_left < meta_needed) {
3097		btf_verifier_log_basic(env, t,
3098				       "meta_left:%u meta_needed:%u",
3099				       meta_left, meta_needed);
3100		return -EINVAL;
3101	}
3102
3103	/* struct type either no name or a valid one */
3104	if (t->name_off &&
3105	    !btf_name_valid_identifier(env->btf, t->name_off)) {
3106		btf_verifier_log_type(env, t, "Invalid name");
3107		return -EINVAL;
3108	}
3109
3110	btf_verifier_log_type(env, t, NULL);
3111
3112	last_offset = 0;
3113	for_each_member(i, t, member) {
3114		if (!btf_name_offset_valid(btf, member->name_off)) {
3115			btf_verifier_log_member(env, t, member,
3116						"Invalid member name_offset:%u",
3117						member->name_off);
3118			return -EINVAL;
3119		}
3120
3121		/* struct member either no name or a valid one */
3122		if (member->name_off &&
3123		    !btf_name_valid_identifier(btf, member->name_off)) {
3124			btf_verifier_log_member(env, t, member, "Invalid name");
3125			return -EINVAL;
3126		}
3127		/* A member cannot be in type void */
3128		if (!member->type || !BTF_TYPE_ID_VALID(member->type)) {
3129			btf_verifier_log_member(env, t, member,
3130						"Invalid type_id");
3131			return -EINVAL;
3132		}
3133
3134		offset = __btf_member_bit_offset(t, member);
3135		if (is_union && offset) {
3136			btf_verifier_log_member(env, t, member,
3137						"Invalid member bits_offset");
3138			return -EINVAL;
3139		}
3140
3141		/*
3142		 * ">" instead of ">=" because the last member could be
3143		 * "char a[0];"
3144		 */
3145		if (last_offset > offset) {
3146			btf_verifier_log_member(env, t, member,
3147						"Invalid member bits_offset");
3148			return -EINVAL;
3149		}
3150
3151		if (BITS_ROUNDUP_BYTES(offset) > struct_size) {
3152			btf_verifier_log_member(env, t, member,
3153						"Member bits_offset exceeds its struct size");
3154			return -EINVAL;
3155		}
3156
3157		btf_verifier_log_member(env, t, member, NULL);
3158		last_offset = offset;
3159	}
3160
3161	return meta_needed;
3162}
3163
3164static int btf_struct_resolve(struct btf_verifier_env *env,
3165			      const struct resolve_vertex *v)
3166{
3167	const struct btf_member *member;
3168	int err;
3169	u16 i;
3170
3171	/* Before continue resolving the next_member,
3172	 * ensure the last member is indeed resolved to a
3173	 * type with size info.
3174	 */
3175	if (v->next_member) {
3176		const struct btf_type *last_member_type;
3177		const struct btf_member *last_member;
3178		u32 last_member_type_id;
3179
3180		last_member = btf_type_member(v->t) + v->next_member - 1;
3181		last_member_type_id = last_member->type;
3182		if (WARN_ON_ONCE(!env_type_is_resolved(env,
3183						       last_member_type_id)))
3184			return -EINVAL;
3185
3186		last_member_type = btf_type_by_id(env->btf,
3187						  last_member_type_id);
3188		if (btf_type_kflag(v->t))
3189			err = btf_type_ops(last_member_type)->check_kflag_member(env, v->t,
3190								last_member,
3191								last_member_type);
3192		else
3193			err = btf_type_ops(last_member_type)->check_member(env, v->t,
3194								last_member,
3195								last_member_type);
3196		if (err)
3197			return err;
3198	}
3199
3200	for_each_member_from(i, v->next_member, v->t, member) {
3201		u32 member_type_id = member->type;
3202		const struct btf_type *member_type = btf_type_by_id(env->btf,
3203								member_type_id);
3204
3205		if (btf_type_nosize_or_null(member_type) ||
3206		    btf_type_is_resolve_source_only(member_type)) {
3207			btf_verifier_log_member(env, v->t, member,
3208						"Invalid member");
3209			return -EINVAL;
3210		}
3211
3212		if (!env_type_is_resolve_sink(env, member_type) &&
3213		    !env_type_is_resolved(env, member_type_id)) {
3214			env_stack_set_next_member(env, i + 1);
3215			return env_stack_push(env, member_type, member_type_id);
3216		}
3217
3218		if (btf_type_kflag(v->t))
3219			err = btf_type_ops(member_type)->check_kflag_member(env, v->t,
3220									    member,
3221									    member_type);
3222		else
3223			err = btf_type_ops(member_type)->check_member(env, v->t,
3224								      member,
3225								      member_type);
3226		if (err)
3227			return err;
3228	}
3229
3230	env_stack_pop_resolved(env, 0, 0);
3231
3232	return 0;
3233}
3234
3235static void btf_struct_log(struct btf_verifier_env *env,
3236			   const struct btf_type *t)
3237{
3238	btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
3239}
3240
3241enum {
3242	BTF_FIELD_IGNORE = 0,
3243	BTF_FIELD_FOUND  = 1,
3244};
3245
3246struct btf_field_info {
3247	enum btf_field_type type;
3248	u32 off;
3249	union {
3250		struct {
3251			u32 type_id;
3252		} kptr;
3253		struct {
3254			const char *node_name;
3255			u32 value_btf_id;
3256		} graph_root;
3257	};
3258};
3259
3260static int btf_find_struct(const struct btf *btf, const struct btf_type *t,
3261			   u32 off, int sz, enum btf_field_type field_type,
3262			   struct btf_field_info *info)
3263{
3264	if (!__btf_type_is_struct(t))
3265		return BTF_FIELD_IGNORE;
3266	if (t->size != sz)
3267		return BTF_FIELD_IGNORE;
3268	info->type = field_type;
3269	info->off = off;
3270	return BTF_FIELD_FOUND;
3271}
3272
3273static int btf_find_kptr(const struct btf *btf, const struct btf_type *t,
3274			 u32 off, int sz, struct btf_field_info *info)
3275{
3276	enum btf_field_type type;
3277	u32 res_id;
3278
3279	/* Permit modifiers on the pointer itself */
3280	if (btf_type_is_volatile(t))
3281		t = btf_type_by_id(btf, t->type);
3282	/* For PTR, sz is always == 8 */
3283	if (!btf_type_is_ptr(t))
3284		return BTF_FIELD_IGNORE;
3285	t = btf_type_by_id(btf, t->type);
3286
3287	if (!btf_type_is_type_tag(t))
3288		return BTF_FIELD_IGNORE;
3289	/* Reject extra tags */
3290	if (btf_type_is_type_tag(btf_type_by_id(btf, t->type)))
3291		return -EINVAL;
3292	if (!strcmp("kptr_untrusted", __btf_name_by_offset(btf, t->name_off)))
3293		type = BPF_KPTR_UNREF;
3294	else if (!strcmp("kptr", __btf_name_by_offset(btf, t->name_off)))
3295		type = BPF_KPTR_REF;
3296	else if (!strcmp("percpu_kptr", __btf_name_by_offset(btf, t->name_off)))
3297		type = BPF_KPTR_PERCPU;
3298	else
3299		return -EINVAL;
3300
3301	/* Get the base type */
3302	t = btf_type_skip_modifiers(btf, t->type, &res_id);
3303	/* Only pointer to struct is allowed */
3304	if (!__btf_type_is_struct(t))
3305		return -EINVAL;
3306
3307	info->type = type;
3308	info->off = off;
3309	info->kptr.type_id = res_id;
3310	return BTF_FIELD_FOUND;
3311}
3312
3313const char *btf_find_decl_tag_value(const struct btf *btf, const struct btf_type *pt,
3314				    int comp_idx, const char *tag_key)
3315{
3316	const char *value = NULL;
3317	int i;
3318
3319	for (i = 1; i < btf_nr_types(btf); i++) {
3320		const struct btf_type *t = btf_type_by_id(btf, i);
3321		int len = strlen(tag_key);
3322
3323		if (!btf_type_is_decl_tag(t))
3324			continue;
3325		if (pt != btf_type_by_id(btf, t->type) ||
3326		    btf_type_decl_tag(t)->component_idx != comp_idx)
3327			continue;
3328		if (strncmp(__btf_name_by_offset(btf, t->name_off), tag_key, len))
3329			continue;
3330		/* Prevent duplicate entries for same type */
3331		if (value)
3332			return ERR_PTR(-EEXIST);
3333		value = __btf_name_by_offset(btf, t->name_off) + len;
3334	}
3335	if (!value)
3336		return ERR_PTR(-ENOENT);
3337	return value;
3338}
3339
3340static int
3341btf_find_graph_root(const struct btf *btf, const struct btf_type *pt,
3342		    const struct btf_type *t, int comp_idx, u32 off,
3343		    int sz, struct btf_field_info *info,
3344		    enum btf_field_type head_type)
3345{
3346	const char *node_field_name;
3347	const char *value_type;
3348	s32 id;
3349
3350	if (!__btf_type_is_struct(t))
3351		return BTF_FIELD_IGNORE;
3352	if (t->size != sz)
3353		return BTF_FIELD_IGNORE;
3354	value_type = btf_find_decl_tag_value(btf, pt, comp_idx, "contains:");
3355	if (IS_ERR(value_type))
3356		return -EINVAL;
3357	node_field_name = strstr(value_type, ":");
3358	if (!node_field_name)
3359		return -EINVAL;
3360	value_type = kstrndup(value_type, node_field_name - value_type, GFP_KERNEL | __GFP_NOWARN);
3361	if (!value_type)
3362		return -ENOMEM;
3363	id = btf_find_by_name_kind(btf, value_type, BTF_KIND_STRUCT);
3364	kfree(value_type);
3365	if (id < 0)
3366		return id;
3367	node_field_name++;
3368	if (str_is_empty(node_field_name))
3369		return -EINVAL;
3370	info->type = head_type;
3371	info->off = off;
3372	info->graph_root.value_btf_id = id;
3373	info->graph_root.node_name = node_field_name;
3374	return BTF_FIELD_FOUND;
3375}
3376
3377#define field_mask_test_name(field_type, field_type_str) \
3378	if (field_mask & field_type && !strcmp(name, field_type_str)) { \
3379		type = field_type;					\
3380		goto end;						\
3381	}
3382
3383static int btf_get_field_type(const char *name, u32 field_mask, u32 *seen_mask,
3384			      int *align, int *sz)
3385{
3386	int type = 0;
3387
3388	if (field_mask & BPF_SPIN_LOCK) {
3389		if (!strcmp(name, "bpf_spin_lock")) {
3390			if (*seen_mask & BPF_SPIN_LOCK)
3391				return -E2BIG;
3392			*seen_mask |= BPF_SPIN_LOCK;
3393			type = BPF_SPIN_LOCK;
3394			goto end;
3395		}
3396	}
3397	if (field_mask & BPF_TIMER) {
3398		if (!strcmp(name, "bpf_timer")) {
3399			if (*seen_mask & BPF_TIMER)
3400				return -E2BIG;
3401			*seen_mask |= BPF_TIMER;
3402			type = BPF_TIMER;
3403			goto end;
3404		}
3405	}
3406	field_mask_test_name(BPF_LIST_HEAD, "bpf_list_head");
3407	field_mask_test_name(BPF_LIST_NODE, "bpf_list_node");
3408	field_mask_test_name(BPF_RB_ROOT,   "bpf_rb_root");
3409	field_mask_test_name(BPF_RB_NODE,   "bpf_rb_node");
3410	field_mask_test_name(BPF_REFCOUNT,  "bpf_refcount");
3411
3412	/* Only return BPF_KPTR when all other types with matchable names fail */
3413	if (field_mask & BPF_KPTR) {
3414		type = BPF_KPTR_REF;
3415		goto end;
3416	}
3417	return 0;
3418end:
3419	*sz = btf_field_type_size(type);
3420	*align = btf_field_type_align(type);
3421	return type;
3422}
3423
3424#undef field_mask_test_name
3425
3426static int btf_find_struct_field(const struct btf *btf,
3427				 const struct btf_type *t, u32 field_mask,
3428				 struct btf_field_info *info, int info_cnt)
3429{
3430	int ret, idx = 0, align, sz, field_type;
3431	const struct btf_member *member;
3432	struct btf_field_info tmp;
3433	u32 i, off, seen_mask = 0;
3434
3435	for_each_member(i, t, member) {
3436		const struct btf_type *member_type = btf_type_by_id(btf,
3437								    member->type);
3438
3439		field_type = btf_get_field_type(__btf_name_by_offset(btf, member_type->name_off),
3440						field_mask, &seen_mask, &align, &sz);
3441		if (field_type == 0)
3442			continue;
3443		if (field_type < 0)
3444			return field_type;
3445
3446		off = __btf_member_bit_offset(t, member);
3447		if (off % 8)
3448			/* valid C code cannot generate such BTF */
3449			return -EINVAL;
3450		off /= 8;
3451		if (off % align)
3452			continue;
3453
3454		switch (field_type) {
3455		case BPF_SPIN_LOCK:
3456		case BPF_TIMER:
3457		case BPF_LIST_NODE:
3458		case BPF_RB_NODE:
3459		case BPF_REFCOUNT:
3460			ret = btf_find_struct(btf, member_type, off, sz, field_type,
3461					      idx < info_cnt ? &info[idx] : &tmp);
3462			if (ret < 0)
3463				return ret;
3464			break;
3465		case BPF_KPTR_UNREF:
3466		case BPF_KPTR_REF:
3467		case BPF_KPTR_PERCPU:
3468			ret = btf_find_kptr(btf, member_type, off, sz,
3469					    idx < info_cnt ? &info[idx] : &tmp);
3470			if (ret < 0)
3471				return ret;
3472			break;
3473		case BPF_LIST_HEAD:
3474		case BPF_RB_ROOT:
3475			ret = btf_find_graph_root(btf, t, member_type,
3476						  i, off, sz,
3477						  idx < info_cnt ? &info[idx] : &tmp,
3478						  field_type);
3479			if (ret < 0)
3480				return ret;
3481			break;
3482		default:
3483			return -EFAULT;
3484		}
3485
3486		if (ret == BTF_FIELD_IGNORE)
3487			continue;
3488		if (idx >= info_cnt)
3489			return -E2BIG;
3490		++idx;
3491	}
3492	return idx;
3493}
3494
3495static int btf_find_datasec_var(const struct btf *btf, const struct btf_type *t,
3496				u32 field_mask, struct btf_field_info *info,
3497				int info_cnt)
3498{
3499	int ret, idx = 0, align, sz, field_type;
3500	const struct btf_var_secinfo *vsi;
3501	struct btf_field_info tmp;
3502	u32 i, off, seen_mask = 0;
3503
3504	for_each_vsi(i, t, vsi) {
3505		const struct btf_type *var = btf_type_by_id(btf, vsi->type);
3506		const struct btf_type *var_type = btf_type_by_id(btf, var->type);
3507
3508		field_type = btf_get_field_type(__btf_name_by_offset(btf, var_type->name_off),
3509						field_mask, &seen_mask, &align, &sz);
3510		if (field_type == 0)
3511			continue;
3512		if (field_type < 0)
3513			return field_type;
3514
3515		off = vsi->offset;
3516		if (vsi->size != sz)
3517			continue;
3518		if (off % align)
3519			continue;
3520
3521		switch (field_type) {
3522		case BPF_SPIN_LOCK:
3523		case BPF_TIMER:
3524		case BPF_LIST_NODE:
3525		case BPF_RB_NODE:
3526		case BPF_REFCOUNT:
3527			ret = btf_find_struct(btf, var_type, off, sz, field_type,
3528					      idx < info_cnt ? &info[idx] : &tmp);
3529			if (ret < 0)
3530				return ret;
3531			break;
3532		case BPF_KPTR_UNREF:
3533		case BPF_KPTR_REF:
3534		case BPF_KPTR_PERCPU:
3535			ret = btf_find_kptr(btf, var_type, off, sz,
3536					    idx < info_cnt ? &info[idx] : &tmp);
3537			if (ret < 0)
3538				return ret;
3539			break;
3540		case BPF_LIST_HEAD:
3541		case BPF_RB_ROOT:
3542			ret = btf_find_graph_root(btf, var, var_type,
3543						  -1, off, sz,
3544						  idx < info_cnt ? &info[idx] : &tmp,
3545						  field_type);
3546			if (ret < 0)
3547				return ret;
3548			break;
3549		default:
3550			return -EFAULT;
3551		}
3552
3553		if (ret == BTF_FIELD_IGNORE)
3554			continue;
3555		if (idx >= info_cnt)
 
3556			return -E2BIG;
3557		++idx;
3558	}
3559	return idx;
3560}
3561
3562static int btf_find_field(const struct btf *btf, const struct btf_type *t,
3563			  u32 field_mask, struct btf_field_info *info,
3564			  int info_cnt)
3565{
3566	if (__btf_type_is_struct(t))
3567		return btf_find_struct_field(btf, t, field_mask, info, info_cnt);
3568	else if (btf_type_is_datasec(t))
3569		return btf_find_datasec_var(btf, t, field_mask, info, info_cnt);
3570	return -EINVAL;
3571}
3572
3573static int btf_parse_kptr(const struct btf *btf, struct btf_field *field,
3574			  struct btf_field_info *info)
3575{
3576	struct module *mod = NULL;
3577	const struct btf_type *t;
3578	/* If a matching btf type is found in kernel or module BTFs, kptr_ref
3579	 * is that BTF, otherwise it's program BTF
3580	 */
3581	struct btf *kptr_btf;
3582	int ret;
3583	s32 id;
3584
3585	/* Find type in map BTF, and use it to look up the matching type
3586	 * in vmlinux or module BTFs, by name and kind.
3587	 */
3588	t = btf_type_by_id(btf, info->kptr.type_id);
3589	id = bpf_find_btf_id(__btf_name_by_offset(btf, t->name_off), BTF_INFO_KIND(t->info),
3590			     &kptr_btf);
3591	if (id == -ENOENT) {
3592		/* btf_parse_kptr should only be called w/ btf = program BTF */
3593		WARN_ON_ONCE(btf_is_kernel(btf));
3594
3595		/* Type exists only in program BTF. Assume that it's a MEM_ALLOC
3596		 * kptr allocated via bpf_obj_new
3597		 */
3598		field->kptr.dtor = NULL;
3599		id = info->kptr.type_id;
3600		kptr_btf = (struct btf *)btf;
3601		btf_get(kptr_btf);
3602		goto found_dtor;
3603	}
3604	if (id < 0)
3605		return id;
3606
3607	/* Find and stash the function pointer for the destruction function that
3608	 * needs to be eventually invoked from the map free path.
3609	 */
3610	if (info->type == BPF_KPTR_REF) {
3611		const struct btf_type *dtor_func;
3612		const char *dtor_func_name;
3613		unsigned long addr;
3614		s32 dtor_btf_id;
3615
3616		/* This call also serves as a whitelist of allowed objects that
3617		 * can be used as a referenced pointer and be stored in a map at
3618		 * the same time.
3619		 */
3620		dtor_btf_id = btf_find_dtor_kfunc(kptr_btf, id);
3621		if (dtor_btf_id < 0) {
3622			ret = dtor_btf_id;
3623			goto end_btf;
3624		}
3625
3626		dtor_func = btf_type_by_id(kptr_btf, dtor_btf_id);
3627		if (!dtor_func) {
3628			ret = -ENOENT;
3629			goto end_btf;
3630		}
3631
3632		if (btf_is_module(kptr_btf)) {
3633			mod = btf_try_get_module(kptr_btf);
3634			if (!mod) {
3635				ret = -ENXIO;
3636				goto end_btf;
3637			}
3638		}
3639
3640		/* We already verified dtor_func to be btf_type_is_func
3641		 * in register_btf_id_dtor_kfuncs.
3642		 */
3643		dtor_func_name = __btf_name_by_offset(kptr_btf, dtor_func->name_off);
3644		addr = kallsyms_lookup_name(dtor_func_name);
3645		if (!addr) {
3646			ret = -EINVAL;
3647			goto end_mod;
3648		}
3649		field->kptr.dtor = (void *)addr;
3650	}
3651
3652found_dtor:
3653	field->kptr.btf_id = id;
3654	field->kptr.btf = kptr_btf;
3655	field->kptr.module = mod;
3656	return 0;
3657end_mod:
3658	module_put(mod);
3659end_btf:
3660	btf_put(kptr_btf);
3661	return ret;
3662}
3663
3664static int btf_parse_graph_root(const struct btf *btf,
3665				struct btf_field *field,
3666				struct btf_field_info *info,
3667				const char *node_type_name,
3668				size_t node_type_align)
3669{
3670	const struct btf_type *t, *n = NULL;
3671	const struct btf_member *member;
3672	u32 offset;
3673	int i;
3674
3675	t = btf_type_by_id(btf, info->graph_root.value_btf_id);
3676	/* We've already checked that value_btf_id is a struct type. We
3677	 * just need to figure out the offset of the list_node, and
3678	 * verify its type.
3679	 */
3680	for_each_member(i, t, member) {
3681		if (strcmp(info->graph_root.node_name,
3682			   __btf_name_by_offset(btf, member->name_off)))
3683			continue;
3684		/* Invalid BTF, two members with same name */
3685		if (n)
3686			return -EINVAL;
3687		n = btf_type_by_id(btf, member->type);
3688		if (!__btf_type_is_struct(n))
3689			return -EINVAL;
3690		if (strcmp(node_type_name, __btf_name_by_offset(btf, n->name_off)))
3691			return -EINVAL;
3692		offset = __btf_member_bit_offset(n, member);
3693		if (offset % 8)
3694			return -EINVAL;
3695		offset /= 8;
3696		if (offset % node_type_align)
 
3697			return -EINVAL;
3698
3699		field->graph_root.btf = (struct btf *)btf;
3700		field->graph_root.value_btf_id = info->graph_root.value_btf_id;
3701		field->graph_root.node_offset = offset;
3702	}
3703	if (!n)
3704		return -ENOENT;
3705	return 0;
3706}
3707
3708static int btf_parse_list_head(const struct btf *btf, struct btf_field *field,
3709			       struct btf_field_info *info)
3710{
3711	return btf_parse_graph_root(btf, field, info, "bpf_list_node",
3712					    __alignof__(struct bpf_list_node));
3713}
3714
3715static int btf_parse_rb_root(const struct btf *btf, struct btf_field *field,
3716			     struct btf_field_info *info)
3717{
3718	return btf_parse_graph_root(btf, field, info, "bpf_rb_node",
3719					    __alignof__(struct bpf_rb_node));
3720}
3721
3722static int btf_field_cmp(const void *_a, const void *_b, const void *priv)
3723{
3724	const struct btf_field *a = (const struct btf_field *)_a;
3725	const struct btf_field *b = (const struct btf_field *)_b;
3726
3727	if (a->offset < b->offset)
3728		return -1;
3729	else if (a->offset > b->offset)
3730		return 1;
3731	return 0;
3732}
3733
3734struct btf_record *btf_parse_fields(const struct btf *btf, const struct btf_type *t,
3735				    u32 field_mask, u32 value_size)
3736{
3737	struct btf_field_info info_arr[BTF_FIELDS_MAX];
3738	u32 next_off = 0, field_type_size;
3739	struct btf_record *rec;
3740	int ret, i, cnt;
3741
3742	ret = btf_find_field(btf, t, field_mask, info_arr, ARRAY_SIZE(info_arr));
3743	if (ret < 0)
3744		return ERR_PTR(ret);
3745	if (!ret)
3746		return NULL;
3747
3748	cnt = ret;
3749	/* This needs to be kzalloc to zero out padding and unused fields, see
3750	 * comment in btf_record_equal.
3751	 */
3752	rec = kzalloc(offsetof(struct btf_record, fields[cnt]), GFP_KERNEL | __GFP_NOWARN);
3753	if (!rec)
3754		return ERR_PTR(-ENOMEM);
3755
3756	rec->spin_lock_off = -EINVAL;
3757	rec->timer_off = -EINVAL;
3758	rec->refcount_off = -EINVAL;
3759	for (i = 0; i < cnt; i++) {
3760		field_type_size = btf_field_type_size(info_arr[i].type);
3761		if (info_arr[i].off + field_type_size > value_size) {
3762			WARN_ONCE(1, "verifier bug off %d size %d", info_arr[i].off, value_size);
3763			ret = -EFAULT;
3764			goto end;
3765		}
3766		if (info_arr[i].off < next_off) {
3767			ret = -EEXIST;
3768			goto end;
3769		}
3770		next_off = info_arr[i].off + field_type_size;
3771
3772		rec->field_mask |= info_arr[i].type;
3773		rec->fields[i].offset = info_arr[i].off;
3774		rec->fields[i].type = info_arr[i].type;
3775		rec->fields[i].size = field_type_size;
3776
3777		switch (info_arr[i].type) {
3778		case BPF_SPIN_LOCK:
3779			WARN_ON_ONCE(rec->spin_lock_off >= 0);
3780			/* Cache offset for faster lookup at runtime */
3781			rec->spin_lock_off = rec->fields[i].offset;
3782			break;
3783		case BPF_TIMER:
3784			WARN_ON_ONCE(rec->timer_off >= 0);
3785			/* Cache offset for faster lookup at runtime */
3786			rec->timer_off = rec->fields[i].offset;
3787			break;
3788		case BPF_REFCOUNT:
3789			WARN_ON_ONCE(rec->refcount_off >= 0);
3790			/* Cache offset for faster lookup at runtime */
3791			rec->refcount_off = rec->fields[i].offset;
3792			break;
3793		case BPF_KPTR_UNREF:
3794		case BPF_KPTR_REF:
3795		case BPF_KPTR_PERCPU:
3796			ret = btf_parse_kptr(btf, &rec->fields[i], &info_arr[i]);
3797			if (ret < 0)
3798				goto end;
3799			break;
3800		case BPF_LIST_HEAD:
3801			ret = btf_parse_list_head(btf, &rec->fields[i], &info_arr[i]);
3802			if (ret < 0)
3803				goto end;
3804			break;
3805		case BPF_RB_ROOT:
3806			ret = btf_parse_rb_root(btf, &rec->fields[i], &info_arr[i]);
3807			if (ret < 0)
3808				goto end;
3809			break;
3810		case BPF_LIST_NODE:
3811		case BPF_RB_NODE:
3812			break;
3813		default:
3814			ret = -EFAULT;
3815			goto end;
3816		}
3817		rec->cnt++;
3818	}
3819
3820	/* bpf_{list_head, rb_node} require bpf_spin_lock */
3821	if ((btf_record_has_field(rec, BPF_LIST_HEAD) ||
3822	     btf_record_has_field(rec, BPF_RB_ROOT)) && rec->spin_lock_off < 0) {
3823		ret = -EINVAL;
3824		goto end;
3825	}
3826
3827	if (rec->refcount_off < 0 &&
3828	    btf_record_has_field(rec, BPF_LIST_NODE) &&
3829	    btf_record_has_field(rec, BPF_RB_NODE)) {
3830		ret = -EINVAL;
3831		goto end;
3832	}
3833
3834	sort_r(rec->fields, rec->cnt, sizeof(struct btf_field), btf_field_cmp,
3835	       NULL, rec);
3836
3837	return rec;
3838end:
3839	btf_record_free(rec);
3840	return ERR_PTR(ret);
3841}
3842
3843int btf_check_and_fixup_fields(const struct btf *btf, struct btf_record *rec)
3844{
3845	int i;
3846
3847	/* There are three types that signify ownership of some other type:
3848	 *  kptr_ref, bpf_list_head, bpf_rb_root.
3849	 * kptr_ref only supports storing kernel types, which can't store
3850	 * references to program allocated local types.
3851	 *
3852	 * Hence we only need to ensure that bpf_{list_head,rb_root} ownership
3853	 * does not form cycles.
3854	 */
3855	if (IS_ERR_OR_NULL(rec) || !(rec->field_mask & BPF_GRAPH_ROOT))
3856		return 0;
3857	for (i = 0; i < rec->cnt; i++) {
3858		struct btf_struct_meta *meta;
3859		u32 btf_id;
3860
3861		if (!(rec->fields[i].type & BPF_GRAPH_ROOT))
3862			continue;
3863		btf_id = rec->fields[i].graph_root.value_btf_id;
3864		meta = btf_find_struct_meta(btf, btf_id);
3865		if (!meta)
3866			return -EFAULT;
3867		rec->fields[i].graph_root.value_rec = meta->record;
3868
3869		/* We need to set value_rec for all root types, but no need
3870		 * to check ownership cycle for a type unless it's also a
3871		 * node type.
3872		 */
3873		if (!(rec->field_mask & BPF_GRAPH_NODE))
3874			continue;
3875
3876		/* We need to ensure ownership acyclicity among all types. The
3877		 * proper way to do it would be to topologically sort all BTF
3878		 * IDs based on the ownership edges, since there can be multiple
3879		 * bpf_{list_head,rb_node} in a type. Instead, we use the
3880		 * following resaoning:
3881		 *
3882		 * - A type can only be owned by another type in user BTF if it
3883		 *   has a bpf_{list,rb}_node. Let's call these node types.
3884		 * - A type can only _own_ another type in user BTF if it has a
3885		 *   bpf_{list_head,rb_root}. Let's call these root types.
3886		 *
3887		 * We ensure that if a type is both a root and node, its
3888		 * element types cannot be root types.
3889		 *
3890		 * To ensure acyclicity:
3891		 *
3892		 * When A is an root type but not a node, its ownership
3893		 * chain can be:
3894		 *	A -> B -> C
3895		 * Where:
3896		 * - A is an root, e.g. has bpf_rb_root.
3897		 * - B is both a root and node, e.g. has bpf_rb_node and
3898		 *   bpf_list_head.
3899		 * - C is only an root, e.g. has bpf_list_node
3900		 *
3901		 * When A is both a root and node, some other type already
3902		 * owns it in the BTF domain, hence it can not own
3903		 * another root type through any of the ownership edges.
3904		 *	A -> B
3905		 * Where:
3906		 * - A is both an root and node.
3907		 * - B is only an node.
3908		 */
3909		if (meta->record->field_mask & BPF_GRAPH_ROOT)
3910			return -ELOOP;
3911	}
3912	return 0;
3913}
3914
3915static void __btf_struct_show(const struct btf *btf, const struct btf_type *t,
3916			      u32 type_id, void *data, u8 bits_offset,
3917			      struct btf_show *show)
3918{
3919	const struct btf_member *member;
3920	void *safe_data;
3921	u32 i;
3922
3923	safe_data = btf_show_start_struct_type(show, t, type_id, data);
3924	if (!safe_data)
3925		return;
3926
3927	for_each_member(i, t, member) {
3928		const struct btf_type *member_type = btf_type_by_id(btf,
3929								member->type);
3930		const struct btf_kind_operations *ops;
3931		u32 member_offset, bitfield_size;
3932		u32 bytes_offset;
3933		u8 bits8_offset;
3934
3935		btf_show_start_member(show, member);
3936
3937		member_offset = __btf_member_bit_offset(t, member);
3938		bitfield_size = __btf_member_bitfield_size(t, member);
3939		bytes_offset = BITS_ROUNDDOWN_BYTES(member_offset);
3940		bits8_offset = BITS_PER_BYTE_MASKED(member_offset);
3941		if (bitfield_size) {
3942			safe_data = btf_show_start_type(show, member_type,
3943							member->type,
3944							data + bytes_offset);
3945			if (safe_data)
3946				btf_bitfield_show(safe_data,
3947						  bits8_offset,
3948						  bitfield_size, show);
3949			btf_show_end_type(show);
3950		} else {
3951			ops = btf_type_ops(member_type);
3952			ops->show(btf, member_type, member->type,
3953				  data + bytes_offset, bits8_offset, show);
3954		}
3955
3956		btf_show_end_member(show);
3957	}
3958
3959	btf_show_end_struct_type(show);
3960}
3961
3962static void btf_struct_show(const struct btf *btf, const struct btf_type *t,
3963			    u32 type_id, void *data, u8 bits_offset,
3964			    struct btf_show *show)
3965{
3966	const struct btf_member *m = show->state.member;
3967
3968	/*
3969	 * First check if any members would be shown (are non-zero).
3970	 * See comments above "struct btf_show" definition for more
3971	 * details on how this works at a high-level.
3972	 */
3973	if (show->state.depth > 0 && !(show->flags & BTF_SHOW_ZERO)) {
3974		if (!show->state.depth_check) {
3975			show->state.depth_check = show->state.depth + 1;
3976			show->state.depth_to_show = 0;
3977		}
3978		__btf_struct_show(btf, t, type_id, data, bits_offset, show);
3979		/* Restore saved member data here */
3980		show->state.member = m;
3981		if (show->state.depth_check != show->state.depth + 1)
3982			return;
3983		show->state.depth_check = 0;
3984
3985		if (show->state.depth_to_show <= show->state.depth)
3986			return;
3987		/*
3988		 * Reaching here indicates we have recursed and found
3989		 * non-zero child values.
3990		 */
3991	}
3992
3993	__btf_struct_show(btf, t, type_id, data, bits_offset, show);
3994}
3995
3996static struct btf_kind_operations struct_ops = {
3997	.check_meta = btf_struct_check_meta,
3998	.resolve = btf_struct_resolve,
3999	.check_member = btf_struct_check_member,
4000	.check_kflag_member = btf_generic_check_kflag_member,
4001	.log_details = btf_struct_log,
4002	.show = btf_struct_show,
4003};
4004
4005static int btf_enum_check_member(struct btf_verifier_env *env,
4006				 const struct btf_type *struct_type,
4007				 const struct btf_member *member,
4008				 const struct btf_type *member_type)
4009{
4010	u32 struct_bits_off = member->offset;
4011	u32 struct_size, bytes_offset;
4012
4013	if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
4014		btf_verifier_log_member(env, struct_type, member,
4015					"Member is not byte aligned");
4016		return -EINVAL;
4017	}
4018
4019	struct_size = struct_type->size;
4020	bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
4021	if (struct_size - bytes_offset < member_type->size) {
4022		btf_verifier_log_member(env, struct_type, member,
4023					"Member exceeds struct_size");
4024		return -EINVAL;
4025	}
4026
4027	return 0;
4028}
4029
4030static int btf_enum_check_kflag_member(struct btf_verifier_env *env,
4031				       const struct btf_type *struct_type,
4032				       const struct btf_member *member,
4033				       const struct btf_type *member_type)
4034{
4035	u32 struct_bits_off, nr_bits, bytes_end, struct_size;
4036	u32 int_bitsize = sizeof(int) * BITS_PER_BYTE;
4037
4038	struct_bits_off = BTF_MEMBER_BIT_OFFSET(member->offset);
4039	nr_bits = BTF_MEMBER_BITFIELD_SIZE(member->offset);
4040	if (!nr_bits) {
4041		if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
4042			btf_verifier_log_member(env, struct_type, member,
4043						"Member is not byte aligned");
4044			return -EINVAL;
4045		}
4046
4047		nr_bits = int_bitsize;
4048	} else if (nr_bits > int_bitsize) {
4049		btf_verifier_log_member(env, struct_type, member,
4050					"Invalid member bitfield_size");
4051		return -EINVAL;
4052	}
4053
4054	struct_size = struct_type->size;
4055	bytes_end = BITS_ROUNDUP_BYTES(struct_bits_off + nr_bits);
4056	if (struct_size < bytes_end) {
4057		btf_verifier_log_member(env, struct_type, member,
4058					"Member exceeds struct_size");
4059		return -EINVAL;
4060	}
4061
4062	return 0;
4063}
4064
4065static s32 btf_enum_check_meta(struct btf_verifier_env *env,
4066			       const struct btf_type *t,
4067			       u32 meta_left)
4068{
4069	const struct btf_enum *enums = btf_type_enum(t);
4070	struct btf *btf = env->btf;
4071	const char *fmt_str;
4072	u16 i, nr_enums;
4073	u32 meta_needed;
4074
4075	nr_enums = btf_type_vlen(t);
4076	meta_needed = nr_enums * sizeof(*enums);
4077
4078	if (meta_left < meta_needed) {
4079		btf_verifier_log_basic(env, t,
4080				       "meta_left:%u meta_needed:%u",
4081				       meta_left, meta_needed);
4082		return -EINVAL;
4083	}
4084
 
 
 
 
 
4085	if (t->size > 8 || !is_power_of_2(t->size)) {
4086		btf_verifier_log_type(env, t, "Unexpected size");
4087		return -EINVAL;
4088	}
4089
4090	/* enum type either no name or a valid one */
4091	if (t->name_off &&
4092	    !btf_name_valid_identifier(env->btf, t->name_off)) {
4093		btf_verifier_log_type(env, t, "Invalid name");
4094		return -EINVAL;
4095	}
4096
4097	btf_verifier_log_type(env, t, NULL);
4098
4099	for (i = 0; i < nr_enums; i++) {
4100		if (!btf_name_offset_valid(btf, enums[i].name_off)) {
4101			btf_verifier_log(env, "\tInvalid name_offset:%u",
4102					 enums[i].name_off);
4103			return -EINVAL;
4104		}
4105
4106		/* enum member must have a valid name */
4107		if (!enums[i].name_off ||
4108		    !btf_name_valid_identifier(btf, enums[i].name_off)) {
4109			btf_verifier_log_type(env, t, "Invalid name");
4110			return -EINVAL;
4111		}
4112
4113		if (env->log.level == BPF_LOG_KERNEL)
4114			continue;
4115		fmt_str = btf_type_kflag(t) ? "\t%s val=%d\n" : "\t%s val=%u\n";
4116		btf_verifier_log(env, fmt_str,
4117				 __btf_name_by_offset(btf, enums[i].name_off),
4118				 enums[i].val);
4119	}
4120
4121	return meta_needed;
4122}
4123
4124static void btf_enum_log(struct btf_verifier_env *env,
4125			 const struct btf_type *t)
4126{
4127	btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
4128}
4129
4130static void btf_enum_show(const struct btf *btf, const struct btf_type *t,
4131			  u32 type_id, void *data, u8 bits_offset,
4132			  struct btf_show *show)
4133{
4134	const struct btf_enum *enums = btf_type_enum(t);
4135	u32 i, nr_enums = btf_type_vlen(t);
4136	void *safe_data;
4137	int v;
4138
4139	safe_data = btf_show_start_type(show, t, type_id, data);
4140	if (!safe_data)
4141		return;
4142
4143	v = *(int *)safe_data;
4144
4145	for (i = 0; i < nr_enums; i++) {
4146		if (v != enums[i].val)
4147			continue;
4148
4149		btf_show_type_value(show, "%s",
4150				    __btf_name_by_offset(btf,
4151							 enums[i].name_off));
4152
4153		btf_show_end_type(show);
4154		return;
4155	}
4156
4157	if (btf_type_kflag(t))
4158		btf_show_type_value(show, "%d", v);
4159	else
4160		btf_show_type_value(show, "%u", v);
4161	btf_show_end_type(show);
4162}
4163
4164static struct btf_kind_operations enum_ops = {
4165	.check_meta = btf_enum_check_meta,
4166	.resolve = btf_df_resolve,
4167	.check_member = btf_enum_check_member,
4168	.check_kflag_member = btf_enum_check_kflag_member,
4169	.log_details = btf_enum_log,
4170	.show = btf_enum_show,
4171};
4172
4173static s32 btf_enum64_check_meta(struct btf_verifier_env *env,
4174				 const struct btf_type *t,
4175				 u32 meta_left)
4176{
4177	const struct btf_enum64 *enums = btf_type_enum64(t);
4178	struct btf *btf = env->btf;
4179	const char *fmt_str;
4180	u16 i, nr_enums;
4181	u32 meta_needed;
4182
4183	nr_enums = btf_type_vlen(t);
4184	meta_needed = nr_enums * sizeof(*enums);
4185
4186	if (meta_left < meta_needed) {
4187		btf_verifier_log_basic(env, t,
4188				       "meta_left:%u meta_needed:%u",
4189				       meta_left, meta_needed);
4190		return -EINVAL;
4191	}
4192
4193	if (t->size > 8 || !is_power_of_2(t->size)) {
4194		btf_verifier_log_type(env, t, "Unexpected size");
4195		return -EINVAL;
4196	}
4197
4198	/* enum type either no name or a valid one */
4199	if (t->name_off &&
4200	    !btf_name_valid_identifier(env->btf, t->name_off)) {
4201		btf_verifier_log_type(env, t, "Invalid name");
4202		return -EINVAL;
4203	}
4204
4205	btf_verifier_log_type(env, t, NULL);
4206
4207	for (i = 0; i < nr_enums; i++) {
4208		if (!btf_name_offset_valid(btf, enums[i].name_off)) {
4209			btf_verifier_log(env, "\tInvalid name_offset:%u",
4210					 enums[i].name_off);
4211			return -EINVAL;
4212		}
4213
4214		/* enum member must have a valid name */
4215		if (!enums[i].name_off ||
4216		    !btf_name_valid_identifier(btf, enums[i].name_off)) {
4217			btf_verifier_log_type(env, t, "Invalid name");
4218			return -EINVAL;
4219		}
4220
4221		if (env->log.level == BPF_LOG_KERNEL)
4222			continue;
4223
4224		fmt_str = btf_type_kflag(t) ? "\t%s val=%lld\n" : "\t%s val=%llu\n";
4225		btf_verifier_log(env, fmt_str,
4226				 __btf_name_by_offset(btf, enums[i].name_off),
4227				 btf_enum64_value(enums + i));
4228	}
4229
4230	return meta_needed;
4231}
4232
4233static void btf_enum64_show(const struct btf *btf, const struct btf_type *t,
4234			    u32 type_id, void *data, u8 bits_offset,
4235			    struct btf_show *show)
4236{
4237	const struct btf_enum64 *enums = btf_type_enum64(t);
4238	u32 i, nr_enums = btf_type_vlen(t);
4239	void *safe_data;
4240	s64 v;
4241
4242	safe_data = btf_show_start_type(show, t, type_id, data);
4243	if (!safe_data)
4244		return;
4245
4246	v = *(u64 *)safe_data;
4247
4248	for (i = 0; i < nr_enums; i++) {
4249		if (v != btf_enum64_value(enums + i))
4250			continue;
4251
4252		btf_show_type_value(show, "%s",
4253				    __btf_name_by_offset(btf,
4254							 enums[i].name_off));
4255
4256		btf_show_end_type(show);
4257		return;
4258	}
4259
4260	if (btf_type_kflag(t))
4261		btf_show_type_value(show, "%lld", v);
4262	else
4263		btf_show_type_value(show, "%llu", v);
4264	btf_show_end_type(show);
4265}
4266
4267static struct btf_kind_operations enum64_ops = {
4268	.check_meta = btf_enum64_check_meta,
4269	.resolve = btf_df_resolve,
4270	.check_member = btf_enum_check_member,
4271	.check_kflag_member = btf_enum_check_kflag_member,
4272	.log_details = btf_enum_log,
4273	.show = btf_enum64_show,
4274};
4275
4276static s32 btf_func_proto_check_meta(struct btf_verifier_env *env,
4277				     const struct btf_type *t,
4278				     u32 meta_left)
4279{
4280	u32 meta_needed = btf_type_vlen(t) * sizeof(struct btf_param);
4281
4282	if (meta_left < meta_needed) {
4283		btf_verifier_log_basic(env, t,
4284				       "meta_left:%u meta_needed:%u",
4285				       meta_left, meta_needed);
4286		return -EINVAL;
4287	}
4288
4289	if (t->name_off) {
4290		btf_verifier_log_type(env, t, "Invalid name");
4291		return -EINVAL;
4292	}
4293
4294	if (btf_type_kflag(t)) {
4295		btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
4296		return -EINVAL;
4297	}
4298
4299	btf_verifier_log_type(env, t, NULL);
4300
4301	return meta_needed;
4302}
4303
4304static void btf_func_proto_log(struct btf_verifier_env *env,
4305			       const struct btf_type *t)
4306{
4307	const struct btf_param *args = (const struct btf_param *)(t + 1);
4308	u16 nr_args = btf_type_vlen(t), i;
4309
4310	btf_verifier_log(env, "return=%u args=(", t->type);
4311	if (!nr_args) {
4312		btf_verifier_log(env, "void");
4313		goto done;
4314	}
4315
4316	if (nr_args == 1 && !args[0].type) {
4317		/* Only one vararg */
4318		btf_verifier_log(env, "vararg");
4319		goto done;
4320	}
4321
4322	btf_verifier_log(env, "%u %s", args[0].type,
4323			 __btf_name_by_offset(env->btf,
4324					      args[0].name_off));
4325	for (i = 1; i < nr_args - 1; i++)
4326		btf_verifier_log(env, ", %u %s", args[i].type,
4327				 __btf_name_by_offset(env->btf,
4328						      args[i].name_off));
4329
4330	if (nr_args > 1) {
4331		const struct btf_param *last_arg = &args[nr_args - 1];
4332
4333		if (last_arg->type)
4334			btf_verifier_log(env, ", %u %s", last_arg->type,
4335					 __btf_name_by_offset(env->btf,
4336							      last_arg->name_off));
4337		else
4338			btf_verifier_log(env, ", vararg");
4339	}
4340
4341done:
4342	btf_verifier_log(env, ")");
4343}
4344
4345static struct btf_kind_operations func_proto_ops = {
4346	.check_meta = btf_func_proto_check_meta,
4347	.resolve = btf_df_resolve,
4348	/*
4349	 * BTF_KIND_FUNC_PROTO cannot be directly referred by
4350	 * a struct's member.
4351	 *
4352	 * It should be a function pointer instead.
4353	 * (i.e. struct's member -> BTF_KIND_PTR -> BTF_KIND_FUNC_PROTO)
4354	 *
4355	 * Hence, there is no btf_func_check_member().
4356	 */
4357	.check_member = btf_df_check_member,
4358	.check_kflag_member = btf_df_check_kflag_member,
4359	.log_details = btf_func_proto_log,
4360	.show = btf_df_show,
4361};
4362
4363static s32 btf_func_check_meta(struct btf_verifier_env *env,
4364			       const struct btf_type *t,
4365			       u32 meta_left)
4366{
4367	if (!t->name_off ||
4368	    !btf_name_valid_identifier(env->btf, t->name_off)) {
4369		btf_verifier_log_type(env, t, "Invalid name");
4370		return -EINVAL;
4371	}
4372
4373	if (btf_type_vlen(t) > BTF_FUNC_GLOBAL) {
4374		btf_verifier_log_type(env, t, "Invalid func linkage");
4375		return -EINVAL;
4376	}
4377
4378	if (btf_type_kflag(t)) {
4379		btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
4380		return -EINVAL;
4381	}
4382
4383	btf_verifier_log_type(env, t, NULL);
4384
4385	return 0;
4386}
4387
4388static int btf_func_resolve(struct btf_verifier_env *env,
4389			    const struct resolve_vertex *v)
4390{
4391	const struct btf_type *t = v->t;
4392	u32 next_type_id = t->type;
4393	int err;
4394
4395	err = btf_func_check(env, t);
4396	if (err)
4397		return err;
4398
4399	env_stack_pop_resolved(env, next_type_id, 0);
4400	return 0;
4401}
4402
4403static struct btf_kind_operations func_ops = {
4404	.check_meta = btf_func_check_meta,
4405	.resolve = btf_func_resolve,
4406	.check_member = btf_df_check_member,
4407	.check_kflag_member = btf_df_check_kflag_member,
4408	.log_details = btf_ref_type_log,
4409	.show = btf_df_show,
4410};
4411
4412static s32 btf_var_check_meta(struct btf_verifier_env *env,
4413			      const struct btf_type *t,
4414			      u32 meta_left)
4415{
4416	const struct btf_var *var;
4417	u32 meta_needed = sizeof(*var);
4418
4419	if (meta_left < meta_needed) {
4420		btf_verifier_log_basic(env, t,
4421				       "meta_left:%u meta_needed:%u",
4422				       meta_left, meta_needed);
4423		return -EINVAL;
4424	}
4425
4426	if (btf_type_vlen(t)) {
4427		btf_verifier_log_type(env, t, "vlen != 0");
4428		return -EINVAL;
4429	}
4430
4431	if (btf_type_kflag(t)) {
4432		btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
4433		return -EINVAL;
4434	}
4435
4436	if (!t->name_off ||
4437	    !__btf_name_valid(env->btf, t->name_off)) {
4438		btf_verifier_log_type(env, t, "Invalid name");
4439		return -EINVAL;
4440	}
4441
4442	/* A var cannot be in type void */
4443	if (!t->type || !BTF_TYPE_ID_VALID(t->type)) {
4444		btf_verifier_log_type(env, t, "Invalid type_id");
4445		return -EINVAL;
4446	}
4447
4448	var = btf_type_var(t);
4449	if (var->linkage != BTF_VAR_STATIC &&
4450	    var->linkage != BTF_VAR_GLOBAL_ALLOCATED) {
4451		btf_verifier_log_type(env, t, "Linkage not supported");
4452		return -EINVAL;
4453	}
4454
4455	btf_verifier_log_type(env, t, NULL);
4456
4457	return meta_needed;
4458}
4459
4460static void btf_var_log(struct btf_verifier_env *env, const struct btf_type *t)
4461{
4462	const struct btf_var *var = btf_type_var(t);
4463
4464	btf_verifier_log(env, "type_id=%u linkage=%u", t->type, var->linkage);
4465}
4466
4467static const struct btf_kind_operations var_ops = {
4468	.check_meta		= btf_var_check_meta,
4469	.resolve		= btf_var_resolve,
4470	.check_member		= btf_df_check_member,
4471	.check_kflag_member	= btf_df_check_kflag_member,
4472	.log_details		= btf_var_log,
4473	.show			= btf_var_show,
4474};
4475
4476static s32 btf_datasec_check_meta(struct btf_verifier_env *env,
4477				  const struct btf_type *t,
4478				  u32 meta_left)
4479{
4480	const struct btf_var_secinfo *vsi;
4481	u64 last_vsi_end_off = 0, sum = 0;
4482	u32 i, meta_needed;
4483
4484	meta_needed = btf_type_vlen(t) * sizeof(*vsi);
4485	if (meta_left < meta_needed) {
4486		btf_verifier_log_basic(env, t,
4487				       "meta_left:%u meta_needed:%u",
4488				       meta_left, meta_needed);
4489		return -EINVAL;
4490	}
4491
4492	if (!t->size) {
4493		btf_verifier_log_type(env, t, "size == 0");
4494		return -EINVAL;
4495	}
4496
4497	if (btf_type_kflag(t)) {
4498		btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
4499		return -EINVAL;
4500	}
4501
4502	if (!t->name_off ||
4503	    !btf_name_valid_section(env->btf, t->name_off)) {
4504		btf_verifier_log_type(env, t, "Invalid name");
4505		return -EINVAL;
4506	}
4507
4508	btf_verifier_log_type(env, t, NULL);
4509
4510	for_each_vsi(i, t, vsi) {
4511		/* A var cannot be in type void */
4512		if (!vsi->type || !BTF_TYPE_ID_VALID(vsi->type)) {
4513			btf_verifier_log_vsi(env, t, vsi,
4514					     "Invalid type_id");
4515			return -EINVAL;
4516		}
4517
4518		if (vsi->offset < last_vsi_end_off || vsi->offset >= t->size) {
4519			btf_verifier_log_vsi(env, t, vsi,
4520					     "Invalid offset");
4521			return -EINVAL;
4522		}
4523
4524		if (!vsi->size || vsi->size > t->size) {
4525			btf_verifier_log_vsi(env, t, vsi,
4526					     "Invalid size");
4527			return -EINVAL;
4528		}
4529
4530		last_vsi_end_off = vsi->offset + vsi->size;
4531		if (last_vsi_end_off > t->size) {
4532			btf_verifier_log_vsi(env, t, vsi,
4533					     "Invalid offset+size");
4534			return -EINVAL;
4535		}
4536
4537		btf_verifier_log_vsi(env, t, vsi, NULL);
4538		sum += vsi->size;
4539	}
4540
4541	if (t->size < sum) {
4542		btf_verifier_log_type(env, t, "Invalid btf_info size");
4543		return -EINVAL;
4544	}
4545
4546	return meta_needed;
4547}
4548
4549static int btf_datasec_resolve(struct btf_verifier_env *env,
4550			       const struct resolve_vertex *v)
4551{
4552	const struct btf_var_secinfo *vsi;
4553	struct btf *btf = env->btf;
4554	u16 i;
4555
4556	env->resolve_mode = RESOLVE_TBD;
4557	for_each_vsi_from(i, v->next_member, v->t, vsi) {
4558		u32 var_type_id = vsi->type, type_id, type_size = 0;
4559		const struct btf_type *var_type = btf_type_by_id(env->btf,
4560								 var_type_id);
4561		if (!var_type || !btf_type_is_var(var_type)) {
4562			btf_verifier_log_vsi(env, v->t, vsi,
4563					     "Not a VAR kind member");
4564			return -EINVAL;
4565		}
4566
4567		if (!env_type_is_resolve_sink(env, var_type) &&
4568		    !env_type_is_resolved(env, var_type_id)) {
4569			env_stack_set_next_member(env, i + 1);
4570			return env_stack_push(env, var_type, var_type_id);
4571		}
4572
4573		type_id = var_type->type;
4574		if (!btf_type_id_size(btf, &type_id, &type_size)) {
4575			btf_verifier_log_vsi(env, v->t, vsi, "Invalid type");
4576			return -EINVAL;
4577		}
4578
4579		if (vsi->size < type_size) {
4580			btf_verifier_log_vsi(env, v->t, vsi, "Invalid size");
4581			return -EINVAL;
4582		}
4583	}
4584
4585	env_stack_pop_resolved(env, 0, 0);
4586	return 0;
4587}
4588
4589static void btf_datasec_log(struct btf_verifier_env *env,
4590			    const struct btf_type *t)
4591{
4592	btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
4593}
4594
4595static void btf_datasec_show(const struct btf *btf,
4596			     const struct btf_type *t, u32 type_id,
4597			     void *data, u8 bits_offset,
4598			     struct btf_show *show)
4599{
4600	const struct btf_var_secinfo *vsi;
4601	const struct btf_type *var;
4602	u32 i;
4603
4604	if (!btf_show_start_type(show, t, type_id, data))
4605		return;
4606
4607	btf_show_type_value(show, "section (\"%s\") = {",
4608			    __btf_name_by_offset(btf, t->name_off));
4609	for_each_vsi(i, t, vsi) {
4610		var = btf_type_by_id(btf, vsi->type);
4611		if (i)
4612			btf_show(show, ",");
4613		btf_type_ops(var)->show(btf, var, vsi->type,
4614					data + vsi->offset, bits_offset, show);
4615	}
4616	btf_show_end_type(show);
4617}
4618
4619static const struct btf_kind_operations datasec_ops = {
4620	.check_meta		= btf_datasec_check_meta,
4621	.resolve		= btf_datasec_resolve,
4622	.check_member		= btf_df_check_member,
4623	.check_kflag_member	= btf_df_check_kflag_member,
4624	.log_details		= btf_datasec_log,
4625	.show			= btf_datasec_show,
4626};
4627
4628static s32 btf_float_check_meta(struct btf_verifier_env *env,
4629				const struct btf_type *t,
4630				u32 meta_left)
4631{
4632	if (btf_type_vlen(t)) {
4633		btf_verifier_log_type(env, t, "vlen != 0");
4634		return -EINVAL;
4635	}
4636
4637	if (btf_type_kflag(t)) {
4638		btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
4639		return -EINVAL;
4640	}
4641
4642	if (t->size != 2 && t->size != 4 && t->size != 8 && t->size != 12 &&
4643	    t->size != 16) {
4644		btf_verifier_log_type(env, t, "Invalid type_size");
4645		return -EINVAL;
4646	}
4647
4648	btf_verifier_log_type(env, t, NULL);
4649
4650	return 0;
4651}
4652
4653static int btf_float_check_member(struct btf_verifier_env *env,
4654				  const struct btf_type *struct_type,
4655				  const struct btf_member *member,
4656				  const struct btf_type *member_type)
4657{
4658	u64 start_offset_bytes;
4659	u64 end_offset_bytes;
4660	u64 misalign_bits;
4661	u64 align_bytes;
4662	u64 align_bits;
4663
4664	/* Different architectures have different alignment requirements, so
4665	 * here we check only for the reasonable minimum. This way we ensure
4666	 * that types after CO-RE can pass the kernel BTF verifier.
4667	 */
4668	align_bytes = min_t(u64, sizeof(void *), member_type->size);
4669	align_bits = align_bytes * BITS_PER_BYTE;
4670	div64_u64_rem(member->offset, align_bits, &misalign_bits);
4671	if (misalign_bits) {
4672		btf_verifier_log_member(env, struct_type, member,
4673					"Member is not properly aligned");
4674		return -EINVAL;
4675	}
4676
4677	start_offset_bytes = member->offset / BITS_PER_BYTE;
4678	end_offset_bytes = start_offset_bytes + member_type->size;
4679	if (end_offset_bytes > struct_type->size) {
4680		btf_verifier_log_member(env, struct_type, member,
4681					"Member exceeds struct_size");
4682		return -EINVAL;
4683	}
4684
4685	return 0;
4686}
4687
4688static void btf_float_log(struct btf_verifier_env *env,
4689			  const struct btf_type *t)
4690{
4691	btf_verifier_log(env, "size=%u", t->size);
4692}
4693
4694static const struct btf_kind_operations float_ops = {
4695	.check_meta = btf_float_check_meta,
4696	.resolve = btf_df_resolve,
4697	.check_member = btf_float_check_member,
4698	.check_kflag_member = btf_generic_check_kflag_member,
4699	.log_details = btf_float_log,
4700	.show = btf_df_show,
4701};
4702
4703static s32 btf_decl_tag_check_meta(struct btf_verifier_env *env,
4704			      const struct btf_type *t,
4705			      u32 meta_left)
4706{
4707	const struct btf_decl_tag *tag;
4708	u32 meta_needed = sizeof(*tag);
4709	s32 component_idx;
4710	const char *value;
4711
4712	if (meta_left < meta_needed) {
4713		btf_verifier_log_basic(env, t,
4714				       "meta_left:%u meta_needed:%u",
4715				       meta_left, meta_needed);
4716		return -EINVAL;
4717	}
4718
4719	value = btf_name_by_offset(env->btf, t->name_off);
4720	if (!value || !value[0]) {
4721		btf_verifier_log_type(env, t, "Invalid value");
4722		return -EINVAL;
4723	}
4724
4725	if (btf_type_vlen(t)) {
4726		btf_verifier_log_type(env, t, "vlen != 0");
4727		return -EINVAL;
4728	}
4729
4730	if (btf_type_kflag(t)) {
4731		btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
4732		return -EINVAL;
4733	}
4734
4735	component_idx = btf_type_decl_tag(t)->component_idx;
4736	if (component_idx < -1) {
4737		btf_verifier_log_type(env, t, "Invalid component_idx");
4738		return -EINVAL;
4739	}
4740
4741	btf_verifier_log_type(env, t, NULL);
4742
4743	return meta_needed;
4744}
4745
4746static int btf_decl_tag_resolve(struct btf_verifier_env *env,
4747			   const struct resolve_vertex *v)
4748{
4749	const struct btf_type *next_type;
4750	const struct btf_type *t = v->t;
4751	u32 next_type_id = t->type;
4752	struct btf *btf = env->btf;
4753	s32 component_idx;
4754	u32 vlen;
4755
4756	next_type = btf_type_by_id(btf, next_type_id);
4757	if (!next_type || !btf_type_is_decl_tag_target(next_type)) {
4758		btf_verifier_log_type(env, v->t, "Invalid type_id");
4759		return -EINVAL;
4760	}
4761
4762	if (!env_type_is_resolve_sink(env, next_type) &&
4763	    !env_type_is_resolved(env, next_type_id))
4764		return env_stack_push(env, next_type, next_type_id);
4765
4766	component_idx = btf_type_decl_tag(t)->component_idx;
4767	if (component_idx != -1) {
4768		if (btf_type_is_var(next_type) || btf_type_is_typedef(next_type)) {
4769			btf_verifier_log_type(env, v->t, "Invalid component_idx");
4770			return -EINVAL;
4771		}
4772
4773		if (btf_type_is_struct(next_type)) {
4774			vlen = btf_type_vlen(next_type);
4775		} else {
4776			/* next_type should be a function */
4777			next_type = btf_type_by_id(btf, next_type->type);
4778			vlen = btf_type_vlen(next_type);
4779		}
4780
4781		if ((u32)component_idx >= vlen) {
4782			btf_verifier_log_type(env, v->t, "Invalid component_idx");
4783			return -EINVAL;
4784		}
4785	}
4786
4787	env_stack_pop_resolved(env, next_type_id, 0);
4788
4789	return 0;
4790}
4791
4792static void btf_decl_tag_log(struct btf_verifier_env *env, const struct btf_type *t)
4793{
4794	btf_verifier_log(env, "type=%u component_idx=%d", t->type,
4795			 btf_type_decl_tag(t)->component_idx);
4796}
4797
4798static const struct btf_kind_operations decl_tag_ops = {
4799	.check_meta = btf_decl_tag_check_meta,
4800	.resolve = btf_decl_tag_resolve,
4801	.check_member = btf_df_check_member,
4802	.check_kflag_member = btf_df_check_kflag_member,
4803	.log_details = btf_decl_tag_log,
4804	.show = btf_df_show,
4805};
4806
4807static int btf_func_proto_check(struct btf_verifier_env *env,
4808				const struct btf_type *t)
4809{
4810	const struct btf_type *ret_type;
4811	const struct btf_param *args;
4812	const struct btf *btf;
4813	u16 nr_args, i;
4814	int err;
4815
4816	btf = env->btf;
4817	args = (const struct btf_param *)(t + 1);
4818	nr_args = btf_type_vlen(t);
4819
4820	/* Check func return type which could be "void" (t->type == 0) */
4821	if (t->type) {
4822		u32 ret_type_id = t->type;
4823
4824		ret_type = btf_type_by_id(btf, ret_type_id);
4825		if (!ret_type) {
4826			btf_verifier_log_type(env, t, "Invalid return type");
4827			return -EINVAL;
4828		}
4829
4830		if (btf_type_is_resolve_source_only(ret_type)) {
4831			btf_verifier_log_type(env, t, "Invalid return type");
4832			return -EINVAL;
4833		}
4834
4835		if (btf_type_needs_resolve(ret_type) &&
4836		    !env_type_is_resolved(env, ret_type_id)) {
4837			err = btf_resolve(env, ret_type, ret_type_id);
4838			if (err)
4839				return err;
4840		}
4841
4842		/* Ensure the return type is a type that has a size */
4843		if (!btf_type_id_size(btf, &ret_type_id, NULL)) {
4844			btf_verifier_log_type(env, t, "Invalid return type");
4845			return -EINVAL;
4846		}
4847	}
4848
4849	if (!nr_args)
4850		return 0;
4851
4852	/* Last func arg type_id could be 0 if it is a vararg */
4853	if (!args[nr_args - 1].type) {
4854		if (args[nr_args - 1].name_off) {
4855			btf_verifier_log_type(env, t, "Invalid arg#%u",
4856					      nr_args);
4857			return -EINVAL;
4858		}
4859		nr_args--;
4860	}
4861
 
4862	for (i = 0; i < nr_args; i++) {
4863		const struct btf_type *arg_type;
4864		u32 arg_type_id;
4865
4866		arg_type_id = args[i].type;
4867		arg_type = btf_type_by_id(btf, arg_type_id);
4868		if (!arg_type) {
4869			btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
4870			return -EINVAL;
4871		}
4872
4873		if (btf_type_is_resolve_source_only(arg_type)) {
4874			btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
4875			return -EINVAL;
4876		}
4877
4878		if (args[i].name_off &&
4879		    (!btf_name_offset_valid(btf, args[i].name_off) ||
4880		     !btf_name_valid_identifier(btf, args[i].name_off))) {
4881			btf_verifier_log_type(env, t,
4882					      "Invalid arg#%u", i + 1);
4883			return -EINVAL;
 
4884		}
4885
4886		if (btf_type_needs_resolve(arg_type) &&
4887		    !env_type_is_resolved(env, arg_type_id)) {
4888			err = btf_resolve(env, arg_type, arg_type_id);
4889			if (err)
4890				return err;
4891		}
4892
4893		if (!btf_type_id_size(btf, &arg_type_id, NULL)) {
4894			btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
4895			return -EINVAL;
 
4896		}
4897	}
4898
4899	return 0;
4900}
4901
4902static int btf_func_check(struct btf_verifier_env *env,
4903			  const struct btf_type *t)
4904{
4905	const struct btf_type *proto_type;
4906	const struct btf_param *args;
4907	const struct btf *btf;
4908	u16 nr_args, i;
4909
4910	btf = env->btf;
4911	proto_type = btf_type_by_id(btf, t->type);
4912
4913	if (!proto_type || !btf_type_is_func_proto(proto_type)) {
4914		btf_verifier_log_type(env, t, "Invalid type_id");
4915		return -EINVAL;
4916	}
4917
4918	args = (const struct btf_param *)(proto_type + 1);
4919	nr_args = btf_type_vlen(proto_type);
4920	for (i = 0; i < nr_args; i++) {
4921		if (!args[i].name_off && args[i].type) {
4922			btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
4923			return -EINVAL;
4924		}
4925	}
4926
4927	return 0;
4928}
4929
4930static const struct btf_kind_operations * const kind_ops[NR_BTF_KINDS] = {
4931	[BTF_KIND_INT] = &int_ops,
4932	[BTF_KIND_PTR] = &ptr_ops,
4933	[BTF_KIND_ARRAY] = &array_ops,
4934	[BTF_KIND_STRUCT] = &struct_ops,
4935	[BTF_KIND_UNION] = &struct_ops,
4936	[BTF_KIND_ENUM] = &enum_ops,
4937	[BTF_KIND_FWD] = &fwd_ops,
4938	[BTF_KIND_TYPEDEF] = &modifier_ops,
4939	[BTF_KIND_VOLATILE] = &modifier_ops,
4940	[BTF_KIND_CONST] = &modifier_ops,
4941	[BTF_KIND_RESTRICT] = &modifier_ops,
4942	[BTF_KIND_FUNC] = &func_ops,
4943	[BTF_KIND_FUNC_PROTO] = &func_proto_ops,
4944	[BTF_KIND_VAR] = &var_ops,
4945	[BTF_KIND_DATASEC] = &datasec_ops,
4946	[BTF_KIND_FLOAT] = &float_ops,
4947	[BTF_KIND_DECL_TAG] = &decl_tag_ops,
4948	[BTF_KIND_TYPE_TAG] = &modifier_ops,
4949	[BTF_KIND_ENUM64] = &enum64_ops,
4950};
4951
4952static s32 btf_check_meta(struct btf_verifier_env *env,
4953			  const struct btf_type *t,
4954			  u32 meta_left)
4955{
4956	u32 saved_meta_left = meta_left;
4957	s32 var_meta_size;
4958
4959	if (meta_left < sizeof(*t)) {
4960		btf_verifier_log(env, "[%u] meta_left:%u meta_needed:%zu",
4961				 env->log_type_id, meta_left, sizeof(*t));
4962		return -EINVAL;
4963	}
4964	meta_left -= sizeof(*t);
4965
4966	if (t->info & ~BTF_INFO_MASK) {
4967		btf_verifier_log(env, "[%u] Invalid btf_info:%x",
4968				 env->log_type_id, t->info);
4969		return -EINVAL;
4970	}
4971
4972	if (BTF_INFO_KIND(t->info) > BTF_KIND_MAX ||
4973	    BTF_INFO_KIND(t->info) == BTF_KIND_UNKN) {
4974		btf_verifier_log(env, "[%u] Invalid kind:%u",
4975				 env->log_type_id, BTF_INFO_KIND(t->info));
4976		return -EINVAL;
4977	}
4978
4979	if (!btf_name_offset_valid(env->btf, t->name_off)) {
4980		btf_verifier_log(env, "[%u] Invalid name_offset:%u",
4981				 env->log_type_id, t->name_off);
4982		return -EINVAL;
4983	}
4984
4985	var_meta_size = btf_type_ops(t)->check_meta(env, t, meta_left);
4986	if (var_meta_size < 0)
4987		return var_meta_size;
4988
4989	meta_left -= var_meta_size;
4990
4991	return saved_meta_left - meta_left;
4992}
4993
4994static int btf_check_all_metas(struct btf_verifier_env *env)
4995{
4996	struct btf *btf = env->btf;
4997	struct btf_header *hdr;
4998	void *cur, *end;
4999
5000	hdr = &btf->hdr;
5001	cur = btf->nohdr_data + hdr->type_off;
5002	end = cur + hdr->type_len;
5003
5004	env->log_type_id = btf->base_btf ? btf->start_id : 1;
5005	while (cur < end) {
5006		struct btf_type *t = cur;
5007		s32 meta_size;
5008
5009		meta_size = btf_check_meta(env, t, end - cur);
5010		if (meta_size < 0)
5011			return meta_size;
5012
5013		btf_add_type(env, t);
5014		cur += meta_size;
5015		env->log_type_id++;
5016	}
5017
5018	return 0;
5019}
5020
5021static bool btf_resolve_valid(struct btf_verifier_env *env,
5022			      const struct btf_type *t,
5023			      u32 type_id)
5024{
5025	struct btf *btf = env->btf;
5026
5027	if (!env_type_is_resolved(env, type_id))
5028		return false;
5029
5030	if (btf_type_is_struct(t) || btf_type_is_datasec(t))
5031		return !btf_resolved_type_id(btf, type_id) &&
5032		       !btf_resolved_type_size(btf, type_id);
5033
5034	if (btf_type_is_decl_tag(t) || btf_type_is_func(t))
5035		return btf_resolved_type_id(btf, type_id) &&
5036		       !btf_resolved_type_size(btf, type_id);
5037
5038	if (btf_type_is_modifier(t) || btf_type_is_ptr(t) ||
5039	    btf_type_is_var(t)) {
5040		t = btf_type_id_resolve(btf, &type_id);
5041		return t &&
5042		       !btf_type_is_modifier(t) &&
5043		       !btf_type_is_var(t) &&
5044		       !btf_type_is_datasec(t);
5045	}
5046
5047	if (btf_type_is_array(t)) {
5048		const struct btf_array *array = btf_type_array(t);
5049		const struct btf_type *elem_type;
5050		u32 elem_type_id = array->type;
5051		u32 elem_size;
5052
5053		elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size);
5054		return elem_type && !btf_type_is_modifier(elem_type) &&
5055			(array->nelems * elem_size ==
5056			 btf_resolved_type_size(btf, type_id));
5057	}
5058
5059	return false;
5060}
5061
5062static int btf_resolve(struct btf_verifier_env *env,
5063		       const struct btf_type *t, u32 type_id)
5064{
5065	u32 save_log_type_id = env->log_type_id;
5066	const struct resolve_vertex *v;
5067	int err = 0;
5068
5069	env->resolve_mode = RESOLVE_TBD;
5070	env_stack_push(env, t, type_id);
5071	while (!err && (v = env_stack_peak(env))) {
5072		env->log_type_id = v->type_id;
5073		err = btf_type_ops(v->t)->resolve(env, v);
5074	}
5075
5076	env->log_type_id = type_id;
5077	if (err == -E2BIG) {
5078		btf_verifier_log_type(env, t,
5079				      "Exceeded max resolving depth:%u",
5080				      MAX_RESOLVE_DEPTH);
5081	} else if (err == -EEXIST) {
5082		btf_verifier_log_type(env, t, "Loop detected");
5083	}
5084
5085	/* Final sanity check */
5086	if (!err && !btf_resolve_valid(env, t, type_id)) {
5087		btf_verifier_log_type(env, t, "Invalid resolve state");
5088		err = -EINVAL;
5089	}
5090
5091	env->log_type_id = save_log_type_id;
5092	return err;
5093}
5094
5095static int btf_check_all_types(struct btf_verifier_env *env)
5096{
5097	struct btf *btf = env->btf;
5098	const struct btf_type *t;
5099	u32 type_id, i;
5100	int err;
5101
5102	err = env_resolve_init(env);
5103	if (err)
5104		return err;
5105
5106	env->phase++;
5107	for (i = btf->base_btf ? 0 : 1; i < btf->nr_types; i++) {
5108		type_id = btf->start_id + i;
5109		t = btf_type_by_id(btf, type_id);
5110
5111		env->log_type_id = type_id;
5112		if (btf_type_needs_resolve(t) &&
5113		    !env_type_is_resolved(env, type_id)) {
5114			err = btf_resolve(env, t, type_id);
5115			if (err)
5116				return err;
5117		}
5118
5119		if (btf_type_is_func_proto(t)) {
5120			err = btf_func_proto_check(env, t);
5121			if (err)
5122				return err;
5123		}
 
 
 
 
 
 
5124	}
5125
5126	return 0;
5127}
5128
5129static int btf_parse_type_sec(struct btf_verifier_env *env)
5130{
5131	const struct btf_header *hdr = &env->btf->hdr;
5132	int err;
5133
5134	/* Type section must align to 4 bytes */
5135	if (hdr->type_off & (sizeof(u32) - 1)) {
5136		btf_verifier_log(env, "Unaligned type_off");
5137		return -EINVAL;
5138	}
5139
5140	if (!env->btf->base_btf && !hdr->type_len) {
5141		btf_verifier_log(env, "No type found");
5142		return -EINVAL;
5143	}
5144
5145	err = btf_check_all_metas(env);
5146	if (err)
5147		return err;
5148
5149	return btf_check_all_types(env);
5150}
5151
5152static int btf_parse_str_sec(struct btf_verifier_env *env)
5153{
5154	const struct btf_header *hdr;
5155	struct btf *btf = env->btf;
5156	const char *start, *end;
5157
5158	hdr = &btf->hdr;
5159	start = btf->nohdr_data + hdr->str_off;
5160	end = start + hdr->str_len;
5161
5162	if (end != btf->data + btf->data_size) {
5163		btf_verifier_log(env, "String section is not at the end");
5164		return -EINVAL;
5165	}
5166
5167	btf->strings = start;
5168
5169	if (btf->base_btf && !hdr->str_len)
5170		return 0;
5171	if (!hdr->str_len || hdr->str_len - 1 > BTF_MAX_NAME_OFFSET || end[-1]) {
5172		btf_verifier_log(env, "Invalid string section");
5173		return -EINVAL;
5174	}
5175	if (!btf->base_btf && start[0]) {
5176		btf_verifier_log(env, "Invalid string section");
5177		return -EINVAL;
5178	}
5179
5180	return 0;
5181}
5182
5183static const size_t btf_sec_info_offset[] = {
5184	offsetof(struct btf_header, type_off),
5185	offsetof(struct btf_header, str_off),
5186};
5187
5188static int btf_sec_info_cmp(const void *a, const void *b)
5189{
5190	const struct btf_sec_info *x = a;
5191	const struct btf_sec_info *y = b;
5192
5193	return (int)(x->off - y->off) ? : (int)(x->len - y->len);
5194}
5195
5196static int btf_check_sec_info(struct btf_verifier_env *env,
5197			      u32 btf_data_size)
5198{
5199	struct btf_sec_info secs[ARRAY_SIZE(btf_sec_info_offset)];
5200	u32 total, expected_total, i;
5201	const struct btf_header *hdr;
5202	const struct btf *btf;
5203
5204	btf = env->btf;
5205	hdr = &btf->hdr;
5206
5207	/* Populate the secs from hdr */
5208	for (i = 0; i < ARRAY_SIZE(btf_sec_info_offset); i++)
5209		secs[i] = *(struct btf_sec_info *)((void *)hdr +
5210						   btf_sec_info_offset[i]);
5211
5212	sort(secs, ARRAY_SIZE(btf_sec_info_offset),
5213	     sizeof(struct btf_sec_info), btf_sec_info_cmp, NULL);
5214
5215	/* Check for gaps and overlap among sections */
5216	total = 0;
5217	expected_total = btf_data_size - hdr->hdr_len;
5218	for (i = 0; i < ARRAY_SIZE(btf_sec_info_offset); i++) {
5219		if (expected_total < secs[i].off) {
5220			btf_verifier_log(env, "Invalid section offset");
5221			return -EINVAL;
5222		}
5223		if (total < secs[i].off) {
5224			/* gap */
5225			btf_verifier_log(env, "Unsupported section found");
5226			return -EINVAL;
5227		}
5228		if (total > secs[i].off) {
5229			btf_verifier_log(env, "Section overlap found");
5230			return -EINVAL;
5231		}
5232		if (expected_total - total < secs[i].len) {
5233			btf_verifier_log(env,
5234					 "Total section length too long");
5235			return -EINVAL;
5236		}
5237		total += secs[i].len;
5238	}
5239
5240	/* There is data other than hdr and known sections */
5241	if (expected_total != total) {
5242		btf_verifier_log(env, "Unsupported section found");
5243		return -EINVAL;
5244	}
5245
5246	return 0;
5247}
5248
5249static int btf_parse_hdr(struct btf_verifier_env *env)
5250{
5251	u32 hdr_len, hdr_copy, btf_data_size;
5252	const struct btf_header *hdr;
5253	struct btf *btf;
 
5254
5255	btf = env->btf;
5256	btf_data_size = btf->data_size;
5257
5258	if (btf_data_size < offsetofend(struct btf_header, hdr_len)) {
 
5259		btf_verifier_log(env, "hdr_len not found");
5260		return -EINVAL;
5261	}
5262
5263	hdr = btf->data;
5264	hdr_len = hdr->hdr_len;
5265	if (btf_data_size < hdr_len) {
5266		btf_verifier_log(env, "btf_header not found");
5267		return -EINVAL;
5268	}
5269
5270	/* Ensure the unsupported header fields are zero */
5271	if (hdr_len > sizeof(btf->hdr)) {
5272		u8 *expected_zero = btf->data + sizeof(btf->hdr);
5273		u8 *end = btf->data + hdr_len;
5274
5275		for (; expected_zero < end; expected_zero++) {
5276			if (*expected_zero) {
5277				btf_verifier_log(env, "Unsupported btf_header");
5278				return -E2BIG;
5279			}
5280		}
5281	}
5282
5283	hdr_copy = min_t(u32, hdr_len, sizeof(btf->hdr));
5284	memcpy(&btf->hdr, btf->data, hdr_copy);
5285
5286	hdr = &btf->hdr;
5287
5288	btf_verifier_log_hdr(env, btf_data_size);
5289
5290	if (hdr->magic != BTF_MAGIC) {
5291		btf_verifier_log(env, "Invalid magic");
5292		return -EINVAL;
5293	}
5294
5295	if (hdr->version != BTF_VERSION) {
5296		btf_verifier_log(env, "Unsupported version");
5297		return -ENOTSUPP;
5298	}
5299
5300	if (hdr->flags) {
5301		btf_verifier_log(env, "Unsupported flags");
5302		return -ENOTSUPP;
5303	}
5304
5305	if (!btf->base_btf && btf_data_size == hdr->hdr_len) {
5306		btf_verifier_log(env, "No data");
5307		return -EINVAL;
5308	}
5309
5310	return btf_check_sec_info(env, btf_data_size);
5311}
5312
5313static const char *alloc_obj_fields[] = {
5314	"bpf_spin_lock",
5315	"bpf_list_head",
5316	"bpf_list_node",
5317	"bpf_rb_root",
5318	"bpf_rb_node",
5319	"bpf_refcount",
5320};
5321
5322static struct btf_struct_metas *
5323btf_parse_struct_metas(struct bpf_verifier_log *log, struct btf *btf)
5324{
5325	union {
5326		struct btf_id_set set;
5327		struct {
5328			u32 _cnt;
5329			u32 _ids[ARRAY_SIZE(alloc_obj_fields)];
5330		} _arr;
5331	} aof;
5332	struct btf_struct_metas *tab = NULL;
5333	int i, n, id, ret;
5334
5335	BUILD_BUG_ON(offsetof(struct btf_id_set, cnt) != 0);
5336	BUILD_BUG_ON(sizeof(struct btf_id_set) != sizeof(u32));
5337
5338	memset(&aof, 0, sizeof(aof));
5339	for (i = 0; i < ARRAY_SIZE(alloc_obj_fields); i++) {
5340		/* Try to find whether this special type exists in user BTF, and
5341		 * if so remember its ID so we can easily find it among members
5342		 * of structs that we iterate in the next loop.
5343		 */
5344		id = btf_find_by_name_kind(btf, alloc_obj_fields[i], BTF_KIND_STRUCT);
5345		if (id < 0)
5346			continue;
5347		aof.set.ids[aof.set.cnt++] = id;
5348	}
5349
5350	if (!aof.set.cnt)
5351		return NULL;
5352	sort(&aof.set.ids, aof.set.cnt, sizeof(aof.set.ids[0]), btf_id_cmp_func, NULL);
5353
5354	n = btf_nr_types(btf);
5355	for (i = 1; i < n; i++) {
5356		struct btf_struct_metas *new_tab;
5357		const struct btf_member *member;
5358		struct btf_struct_meta *type;
5359		struct btf_record *record;
5360		const struct btf_type *t;
5361		int j, tab_cnt;
5362
5363		t = btf_type_by_id(btf, i);
5364		if (!t) {
5365			ret = -EINVAL;
5366			goto free;
5367		}
5368		if (!__btf_type_is_struct(t))
5369			continue;
5370
5371		cond_resched();
5372
5373		for_each_member(j, t, member) {
5374			if (btf_id_set_contains(&aof.set, member->type))
5375				goto parse;
5376		}
5377		continue;
5378	parse:
5379		tab_cnt = tab ? tab->cnt : 0;
5380		new_tab = krealloc(tab, offsetof(struct btf_struct_metas, types[tab_cnt + 1]),
5381				   GFP_KERNEL | __GFP_NOWARN);
5382		if (!new_tab) {
5383			ret = -ENOMEM;
5384			goto free;
5385		}
5386		if (!tab)
5387			new_tab->cnt = 0;
5388		tab = new_tab;
5389
5390		type = &tab->types[tab->cnt];
5391		type->btf_id = i;
5392		record = btf_parse_fields(btf, t, BPF_SPIN_LOCK | BPF_LIST_HEAD | BPF_LIST_NODE |
5393						  BPF_RB_ROOT | BPF_RB_NODE | BPF_REFCOUNT, t->size);
5394		/* The record cannot be unset, treat it as an error if so */
5395		if (IS_ERR_OR_NULL(record)) {
5396			ret = PTR_ERR_OR_ZERO(record) ?: -EFAULT;
5397			goto free;
5398		}
5399		type->record = record;
5400		tab->cnt++;
5401	}
5402	return tab;
5403free:
5404	btf_struct_metas_free(tab);
5405	return ERR_PTR(ret);
5406}
5407
5408struct btf_struct_meta *btf_find_struct_meta(const struct btf *btf, u32 btf_id)
5409{
5410	struct btf_struct_metas *tab;
5411
5412	BUILD_BUG_ON(offsetof(struct btf_struct_meta, btf_id) != 0);
5413	tab = btf->struct_meta_tab;
5414	if (!tab)
5415		return NULL;
5416	return bsearch(&btf_id, tab->types, tab->cnt, sizeof(tab->types[0]), btf_id_cmp_func);
5417}
5418
5419static int btf_check_type_tags(struct btf_verifier_env *env,
5420			       struct btf *btf, int start_id)
5421{
5422	int i, n, good_id = start_id - 1;
5423	bool in_tags;
5424
5425	n = btf_nr_types(btf);
5426	for (i = start_id; i < n; i++) {
5427		const struct btf_type *t;
5428		int chain_limit = 32;
5429		u32 cur_id = i;
5430
5431		t = btf_type_by_id(btf, i);
5432		if (!t)
5433			return -EINVAL;
5434		if (!btf_type_is_modifier(t))
5435			continue;
5436
5437		cond_resched();
5438
5439		in_tags = btf_type_is_type_tag(t);
5440		while (btf_type_is_modifier(t)) {
5441			if (!chain_limit--) {
5442				btf_verifier_log(env, "Max chain length or cycle detected");
5443				return -ELOOP;
5444			}
5445			if (btf_type_is_type_tag(t)) {
5446				if (!in_tags) {
5447					btf_verifier_log(env, "Type tags don't precede modifiers");
5448					return -EINVAL;
5449				}
5450			} else if (in_tags) {
5451				in_tags = false;
5452			}
5453			if (cur_id <= good_id)
5454				break;
5455			/* Move to next type */
5456			cur_id = t->type;
5457			t = btf_type_by_id(btf, cur_id);
5458			if (!t)
5459				return -EINVAL;
5460		}
5461		good_id = i;
5462	}
5463	return 0;
5464}
5465
5466static int finalize_log(struct bpf_verifier_log *log, bpfptr_t uattr, u32 uattr_size)
5467{
5468	u32 log_true_size;
5469	int err;
5470
5471	err = bpf_vlog_finalize(log, &log_true_size);
5472
5473	if (uattr_size >= offsetofend(union bpf_attr, btf_log_true_size) &&
5474	    copy_to_bpfptr_offset(uattr, offsetof(union bpf_attr, btf_log_true_size),
5475				  &log_true_size, sizeof(log_true_size)))
5476		err = -EFAULT;
5477
5478	return err;
5479}
5480
5481static struct btf *btf_parse(const union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size)
5482{
5483	bpfptr_t btf_data = make_bpfptr(attr->btf, uattr.is_kernel);
5484	char __user *log_ubuf = u64_to_user_ptr(attr->btf_log_buf);
5485	struct btf_struct_metas *struct_meta_tab;
5486	struct btf_verifier_env *env = NULL;
 
5487	struct btf *btf = NULL;
5488	u8 *data;
5489	int err, ret;
5490
5491	if (attr->btf_size > BTF_MAX_SIZE)
5492		return ERR_PTR(-E2BIG);
5493
5494	env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN);
5495	if (!env)
5496		return ERR_PTR(-ENOMEM);
5497
5498	/* user could have requested verbose verifier output
5499	 * and supplied buffer to store the verification trace
5500	 */
5501	err = bpf_vlog_init(&env->log, attr->btf_log_level,
5502			    log_ubuf, attr->btf_log_size);
5503	if (err)
5504		goto errout_free;
 
 
 
 
 
 
 
 
 
5505
5506	btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN);
5507	if (!btf) {
5508		err = -ENOMEM;
5509		goto errout;
5510	}
5511	env->btf = btf;
5512
5513	data = kvmalloc(attr->btf_size, GFP_KERNEL | __GFP_NOWARN);
5514	if (!data) {
5515		err = -ENOMEM;
5516		goto errout;
5517	}
5518
5519	btf->data = data;
5520	btf->data_size = attr->btf_size;
5521
5522	if (copy_from_bpfptr(data, btf_data, attr->btf_size)) {
5523		err = -EFAULT;
5524		goto errout;
5525	}
5526
5527	err = btf_parse_hdr(env);
5528	if (err)
5529		goto errout;
5530
5531	btf->nohdr_data = btf->data + btf->hdr.hdr_len;
5532
5533	err = btf_parse_str_sec(env);
5534	if (err)
5535		goto errout;
5536
5537	err = btf_parse_type_sec(env);
5538	if (err)
5539		goto errout;
5540
5541	err = btf_check_type_tags(env, btf, 1);
5542	if (err)
5543		goto errout;
5544
5545	struct_meta_tab = btf_parse_struct_metas(&env->log, btf);
5546	if (IS_ERR(struct_meta_tab)) {
5547		err = PTR_ERR(struct_meta_tab);
5548		goto errout;
5549	}
5550	btf->struct_meta_tab = struct_meta_tab;
5551
5552	if (struct_meta_tab) {
5553		int i;
5554
5555		for (i = 0; i < struct_meta_tab->cnt; i++) {
5556			err = btf_check_and_fixup_fields(btf, struct_meta_tab->types[i].record);
5557			if (err < 0)
5558				goto errout_meta;
5559		}
5560	}
5561
5562	err = finalize_log(&env->log, uattr, uattr_size);
5563	if (err)
5564		goto errout_free;
5565
5566	btf_verifier_env_free(env);
5567	refcount_set(&btf->refcnt, 1);
5568	return btf;
5569
5570errout_meta:
5571	btf_free_struct_meta_tab(btf);
5572errout:
5573	/* overwrite err with -ENOSPC or -EFAULT */
5574	ret = finalize_log(&env->log, uattr, uattr_size);
5575	if (ret)
5576		err = ret;
5577errout_free:
5578	btf_verifier_env_free(env);
5579	if (btf)
5580		btf_free(btf);
5581	return ERR_PTR(err);
5582}
5583
5584extern char __weak __start_BTF[];
5585extern char __weak __stop_BTF[];
5586extern struct btf *btf_vmlinux;
5587
5588#define BPF_MAP_TYPE(_id, _ops)
5589#define BPF_LINK_TYPE(_id, _name)
5590static union {
5591	struct bpf_ctx_convert {
5592#define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
5593	prog_ctx_type _id##_prog; \
5594	kern_ctx_type _id##_kern;
5595#include <linux/bpf_types.h>
5596#undef BPF_PROG_TYPE
5597	} *__t;
5598	/* 't' is written once under lock. Read many times. */
5599	const struct btf_type *t;
5600} bpf_ctx_convert;
5601enum {
5602#define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
5603	__ctx_convert##_id,
5604#include <linux/bpf_types.h>
5605#undef BPF_PROG_TYPE
5606	__ctx_convert_unused, /* to avoid empty enum in extreme .config */
5607};
5608static u8 bpf_ctx_convert_map[] = {
5609#define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
5610	[_id] = __ctx_convert##_id,
5611#include <linux/bpf_types.h>
5612#undef BPF_PROG_TYPE
5613	0, /* avoid empty array */
5614};
5615#undef BPF_MAP_TYPE
5616#undef BPF_LINK_TYPE
5617
5618static const struct btf_type *find_canonical_prog_ctx_type(enum bpf_prog_type prog_type)
5619{
5620	const struct btf_type *conv_struct;
5621	const struct btf_member *ctx_type;
5622
5623	conv_struct = bpf_ctx_convert.t;
5624	if (!conv_struct)
5625		return NULL;
5626	/* prog_type is valid bpf program type. No need for bounds check. */
5627	ctx_type = btf_type_member(conv_struct) + bpf_ctx_convert_map[prog_type] * 2;
5628	/* ctx_type is a pointer to prog_ctx_type in vmlinux.
5629	 * Like 'struct __sk_buff'
5630	 */
5631	return btf_type_by_id(btf_vmlinux, ctx_type->type);
5632}
5633
5634static int find_kern_ctx_type_id(enum bpf_prog_type prog_type)
5635{
5636	const struct btf_type *conv_struct;
5637	const struct btf_member *ctx_type;
5638
5639	conv_struct = bpf_ctx_convert.t;
5640	if (!conv_struct)
5641		return -EFAULT;
5642	/* prog_type is valid bpf program type. No need for bounds check. */
5643	ctx_type = btf_type_member(conv_struct) + bpf_ctx_convert_map[prog_type] * 2 + 1;
5644	/* ctx_type is a pointer to prog_ctx_type in vmlinux.
5645	 * Like 'struct sk_buff'
5646	 */
5647	return ctx_type->type;
5648}
5649
5650const struct btf_type *
5651btf_get_prog_ctx_type(struct bpf_verifier_log *log, const struct btf *btf,
5652		      const struct btf_type *t, enum bpf_prog_type prog_type,
5653		      int arg)
5654{
5655	const struct btf_type *ctx_type;
 
 
5656	const char *tname, *ctx_tname;
5657
 
 
 
 
 
5658	t = btf_type_by_id(btf, t->type);
5659	while (btf_type_is_modifier(t))
5660		t = btf_type_by_id(btf, t->type);
5661	if (!btf_type_is_struct(t)) {
5662		/* Only pointer to struct is supported for now.
5663		 * That means that BPF_PROG_TYPE_TRACEPOINT with BTF
5664		 * is not supported yet.
5665		 * BPF_PROG_TYPE_RAW_TRACEPOINT is fine.
5666		 */
5667		return NULL;
5668	}
5669	tname = btf_name_by_offset(btf, t->name_off);
5670	if (!tname) {
5671		bpf_log(log, "arg#%d struct doesn't have a name\n", arg);
5672		return NULL;
5673	}
5674
5675	ctx_type = find_canonical_prog_ctx_type(prog_type);
5676	if (!ctx_type) {
5677		bpf_log(log, "btf_vmlinux is malformed\n");
 
 
 
5678		/* should not happen */
5679		return NULL;
5680	}
5681again:
5682	ctx_tname = btf_name_by_offset(btf_vmlinux, ctx_type->name_off);
5683	if (!ctx_tname) {
5684		/* should not happen */
5685		bpf_log(log, "Please fix kernel include/linux/bpf_types.h\n");
5686		return NULL;
5687	}
5688	/* only compare that prog's ctx type name is the same as
5689	 * kernel expects. No need to compare field by field.
5690	 * It's ok for bpf prog to do:
5691	 * struct __sk_buff {};
5692	 * int socket_filter_bpf_prog(struct __sk_buff *skb)
5693	 * { // no fields of skb are ever used }
5694	 */
5695	if (strcmp(ctx_tname, "__sk_buff") == 0 && strcmp(tname, "sk_buff") == 0)
5696		return ctx_type;
5697	if (strcmp(ctx_tname, "xdp_md") == 0 && strcmp(tname, "xdp_buff") == 0)
5698		return ctx_type;
5699	if (strcmp(ctx_tname, tname)) {
5700		/* bpf_user_pt_regs_t is a typedef, so resolve it to
5701		 * underlying struct and check name again
5702		 */
5703		if (!btf_type_is_modifier(ctx_type))
5704			return NULL;
5705		while (btf_type_is_modifier(ctx_type))
5706			ctx_type = btf_type_by_id(btf_vmlinux, ctx_type->type);
5707		goto again;
5708	}
5709	return ctx_type;
5710}
5711
5712/* forward declarations for arch-specific underlying types of
5713 * bpf_user_pt_regs_t; this avoids the need for arch-specific #ifdef
5714 * compilation guards below for BPF_PROG_TYPE_PERF_EVENT checks, but still
5715 * works correctly with __builtin_types_compatible_p() on respective
5716 * architectures
5717 */
5718struct user_regs_struct;
5719struct user_pt_regs;
 
 
5720
5721static int btf_validate_prog_ctx_type(struct bpf_verifier_log *log, const struct btf *btf,
5722				      const struct btf_type *t, int arg,
5723				      enum bpf_prog_type prog_type,
5724				      enum bpf_attach_type attach_type)
5725{
5726	const struct btf_type *ctx_type;
5727	const char *tname, *ctx_tname;
5728
5729	if (!btf_is_ptr(t)) {
5730		bpf_log(log, "arg#%d type isn't a pointer\n", arg);
5731		return -EINVAL;
5732	}
5733	t = btf_type_by_id(btf, t->type);
5734
5735	/* KPROBE and PERF_EVENT programs allow bpf_user_pt_regs_t typedef */
5736	if (prog_type == BPF_PROG_TYPE_KPROBE || prog_type == BPF_PROG_TYPE_PERF_EVENT) {
5737		while (btf_type_is_modifier(t) && !btf_type_is_typedef(t))
5738			t = btf_type_by_id(btf, t->type);
5739
5740		if (btf_type_is_typedef(t)) {
5741			tname = btf_name_by_offset(btf, t->name_off);
5742			if (tname && strcmp(tname, "bpf_user_pt_regs_t") == 0)
5743				return 0;
5744		}
5745	}
5746
5747	/* all other program types don't use typedefs for context type */
5748	while (btf_type_is_modifier(t))
5749		t = btf_type_by_id(btf, t->type);
5750
5751	/* `void *ctx __arg_ctx` is always valid */
5752	if (btf_type_is_void(t))
5753		return 0;
5754
5755	tname = btf_name_by_offset(btf, t->name_off);
5756	if (str_is_empty(tname)) {
5757		bpf_log(log, "arg#%d type doesn't have a name\n", arg);
5758		return -EINVAL;
5759	}
5760
5761	/* special cases */
5762	switch (prog_type) {
5763	case BPF_PROG_TYPE_KPROBE:
5764		if (__btf_type_is_struct(t) && strcmp(tname, "pt_regs") == 0)
5765			return 0;
5766		break;
5767	case BPF_PROG_TYPE_PERF_EVENT:
5768		if (__builtin_types_compatible_p(bpf_user_pt_regs_t, struct pt_regs) &&
5769		    __btf_type_is_struct(t) && strcmp(tname, "pt_regs") == 0)
5770			return 0;
5771		if (__builtin_types_compatible_p(bpf_user_pt_regs_t, struct user_pt_regs) &&
5772		    __btf_type_is_struct(t) && strcmp(tname, "user_pt_regs") == 0)
5773			return 0;
5774		if (__builtin_types_compatible_p(bpf_user_pt_regs_t, struct user_regs_struct) &&
5775		    __btf_type_is_struct(t) && strcmp(tname, "user_regs_struct") == 0)
5776			return 0;
5777		break;
5778	case BPF_PROG_TYPE_RAW_TRACEPOINT:
5779	case BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE:
5780		/* allow u64* as ctx */
5781		if (btf_is_int(t) && t->size == 8)
5782			return 0;
5783		break;
5784	case BPF_PROG_TYPE_TRACING:
5785		switch (attach_type) {
5786		case BPF_TRACE_RAW_TP:
5787			/* tp_btf program is TRACING, so need special case here */
5788			if (__btf_type_is_struct(t) &&
5789			    strcmp(tname, "bpf_raw_tracepoint_args") == 0)
5790				return 0;
5791			/* allow u64* as ctx */
5792			if (btf_is_int(t) && t->size == 8)
5793				return 0;
5794			break;
5795		case BPF_TRACE_ITER:
5796			/* allow struct bpf_iter__xxx types only */
5797			if (__btf_type_is_struct(t) &&
5798			    strncmp(tname, "bpf_iter__", sizeof("bpf_iter__") - 1) == 0)
5799				return 0;
5800			break;
5801		case BPF_TRACE_FENTRY:
5802		case BPF_TRACE_FEXIT:
5803		case BPF_MODIFY_RETURN:
5804			/* allow u64* as ctx */
5805			if (btf_is_int(t) && t->size == 8)
5806				return 0;
5807			break;
5808		default:
5809			break;
5810		}
5811		break;
5812	case BPF_PROG_TYPE_LSM:
5813	case BPF_PROG_TYPE_STRUCT_OPS:
5814		/* allow u64* as ctx */
5815		if (btf_is_int(t) && t->size == 8)
5816			return 0;
5817		break;
5818	case BPF_PROG_TYPE_TRACEPOINT:
5819	case BPF_PROG_TYPE_SYSCALL:
5820	case BPF_PROG_TYPE_EXT:
5821		return 0; /* anything goes */
5822	default:
5823		break;
5824	}
5825
5826	ctx_type = find_canonical_prog_ctx_type(prog_type);
5827	if (!ctx_type) {
5828		/* should not happen */
5829		bpf_log(log, "btf_vmlinux is malformed\n");
5830		return -EINVAL;
5831	}
5832
5833	/* resolve typedefs and check that underlying structs are matching as well */
5834	while (btf_type_is_modifier(ctx_type))
5835		ctx_type = btf_type_by_id(btf_vmlinux, ctx_type->type);
5836
5837	/* if program type doesn't have distinctly named struct type for
5838	 * context, then __arg_ctx argument can only be `void *`, which we
5839	 * already checked above
5840	 */
5841	if (!__btf_type_is_struct(ctx_type)) {
5842		bpf_log(log, "arg#%d should be void pointer\n", arg);
5843		return -EINVAL;
5844	}
5845
5846	ctx_tname = btf_name_by_offset(btf_vmlinux, ctx_type->name_off);
5847	if (!__btf_type_is_struct(t) || strcmp(ctx_tname, tname) != 0) {
5848		bpf_log(log, "arg#%d should be `struct %s *`\n", arg, ctx_tname);
5849		return -EINVAL;
5850	}
5851
5852	return 0;
5853}
5854
5855static int btf_translate_to_vmlinux(struct bpf_verifier_log *log,
5856				     struct btf *btf,
5857				     const struct btf_type *t,
5858				     enum bpf_prog_type prog_type,
5859				     int arg)
5860{
5861	if (!btf_get_prog_ctx_type(log, btf, t, prog_type, arg))
5862		return -ENOENT;
5863	return find_kern_ctx_type_id(prog_type);
5864}
5865
5866int get_kern_ctx_btf_id(struct bpf_verifier_log *log, enum bpf_prog_type prog_type)
5867{
5868	const struct btf_member *kctx_member;
5869	const struct btf_type *conv_struct;
5870	const struct btf_type *kctx_type;
5871	u32 kctx_type_id;
5872
5873	conv_struct = bpf_ctx_convert.t;
5874	/* get member for kernel ctx type */
5875	kctx_member = btf_type_member(conv_struct) + bpf_ctx_convert_map[prog_type] * 2 + 1;
5876	kctx_type_id = kctx_member->type;
5877	kctx_type = btf_type_by_id(btf_vmlinux, kctx_type_id);
5878	if (!btf_type_is_struct(kctx_type)) {
5879		bpf_log(log, "kern ctx type id %u is not a struct\n", kctx_type_id);
5880		return -EINVAL;
5881	}
5882
5883	return kctx_type_id;
 
 
 
 
5884}
5885
5886BTF_ID_LIST(bpf_ctx_convert_btf_id)
5887BTF_ID(struct, bpf_ctx_convert)
5888
5889struct btf *btf_parse_vmlinux(void)
5890{
5891	struct btf_verifier_env *env = NULL;
5892	struct bpf_verifier_log *log;
5893	struct btf *btf = NULL;
5894	int err;
5895
5896	env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN);
5897	if (!env)
5898		return ERR_PTR(-ENOMEM);
5899
5900	log = &env->log;
5901	log->level = BPF_LOG_KERNEL;
5902
5903	btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN);
5904	if (!btf) {
5905		err = -ENOMEM;
5906		goto errout;
5907	}
5908	env->btf = btf;
5909
5910	btf->data = __start_BTF;
5911	btf->data_size = __stop_BTF - __start_BTF;
5912	btf->kernel_btf = true;
5913	snprintf(btf->name, sizeof(btf->name), "vmlinux");
5914
5915	err = btf_parse_hdr(env);
5916	if (err)
5917		goto errout;
5918
5919	btf->nohdr_data = btf->data + btf->hdr.hdr_len;
5920
5921	err = btf_parse_str_sec(env);
5922	if (err)
5923		goto errout;
5924
5925	err = btf_check_all_metas(env);
5926	if (err)
5927		goto errout;
5928
5929	err = btf_check_type_tags(env, btf, 1);
5930	if (err)
5931		goto errout;
5932
5933	/* btf_parse_vmlinux() runs under bpf_verifier_lock */
5934	bpf_ctx_convert.t = btf_type_by_id(btf, bpf_ctx_convert_btf_id[0]);
5935
 
 
 
 
 
5936	bpf_struct_ops_init(btf, log);
5937
5938	refcount_set(&btf->refcnt, 1);
5939
5940	err = btf_alloc_id(btf);
5941	if (err)
5942		goto errout;
5943
5944	btf_verifier_env_free(env);
5945	return btf;
5946
5947errout:
5948	btf_verifier_env_free(env);
5949	if (btf) {
5950		kvfree(btf->types);
5951		kfree(btf);
5952	}
5953	return ERR_PTR(err);
5954}
5955
5956#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
5957
5958static struct btf *btf_parse_module(const char *module_name, const void *data, unsigned int data_size)
5959{
5960	struct btf_verifier_env *env = NULL;
5961	struct bpf_verifier_log *log;
5962	struct btf *btf = NULL, *base_btf;
5963	int err;
5964
5965	base_btf = bpf_get_btf_vmlinux();
5966	if (IS_ERR(base_btf))
5967		return base_btf;
5968	if (!base_btf)
5969		return ERR_PTR(-EINVAL);
5970
5971	env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN);
5972	if (!env)
5973		return ERR_PTR(-ENOMEM);
5974
5975	log = &env->log;
5976	log->level = BPF_LOG_KERNEL;
5977
5978	btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN);
5979	if (!btf) {
5980		err = -ENOMEM;
5981		goto errout;
5982	}
5983	env->btf = btf;
5984
5985	btf->base_btf = base_btf;
5986	btf->start_id = base_btf->nr_types;
5987	btf->start_str_off = base_btf->hdr.str_len;
5988	btf->kernel_btf = true;
5989	snprintf(btf->name, sizeof(btf->name), "%s", module_name);
5990
5991	btf->data = kvmalloc(data_size, GFP_KERNEL | __GFP_NOWARN);
5992	if (!btf->data) {
5993		err = -ENOMEM;
5994		goto errout;
5995	}
5996	memcpy(btf->data, data, data_size);
5997	btf->data_size = data_size;
5998
5999	err = btf_parse_hdr(env);
6000	if (err)
6001		goto errout;
6002
6003	btf->nohdr_data = btf->data + btf->hdr.hdr_len;
6004
6005	err = btf_parse_str_sec(env);
6006	if (err)
6007		goto errout;
6008
6009	err = btf_check_all_metas(env);
6010	if (err)
6011		goto errout;
6012
6013	err = btf_check_type_tags(env, btf, btf_nr_types(base_btf));
6014	if (err)
6015		goto errout;
6016
6017	btf_verifier_env_free(env);
6018	refcount_set(&btf->refcnt, 1);
6019	return btf;
6020
6021errout:
6022	btf_verifier_env_free(env);
6023	if (btf) {
6024		kvfree(btf->data);
6025		kvfree(btf->types);
6026		kfree(btf);
6027	}
6028	return ERR_PTR(err);
6029}
6030
6031#endif /* CONFIG_DEBUG_INFO_BTF_MODULES */
6032
6033struct btf *bpf_prog_get_target_btf(const struct bpf_prog *prog)
6034{
6035	struct bpf_prog *tgt_prog = prog->aux->dst_prog;
6036
6037	if (tgt_prog)
6038		return tgt_prog->aux->btf;
6039	else
6040		return prog->aux->attach_btf;
6041}
6042
6043static bool is_int_ptr(struct btf *btf, const struct btf_type *t)
6044{
6045	/* skip modifiers */
6046	t = btf_type_skip_modifiers(btf, t->type, NULL);
6047
6048	return btf_type_is_int(t);
6049}
6050
6051static u32 get_ctx_arg_idx(struct btf *btf, const struct btf_type *func_proto,
6052			   int off)
6053{
6054	const struct btf_param *args;
6055	const struct btf_type *t;
6056	u32 offset = 0, nr_args;
6057	int i;
6058
6059	if (!func_proto)
6060		return off / 8;
6061
6062	nr_args = btf_type_vlen(func_proto);
6063	args = (const struct btf_param *)(func_proto + 1);
6064	for (i = 0; i < nr_args; i++) {
6065		t = btf_type_skip_modifiers(btf, args[i].type, NULL);
6066		offset += btf_type_is_ptr(t) ? 8 : roundup(t->size, 8);
6067		if (off < offset)
6068			return i;
6069	}
6070
6071	t = btf_type_skip_modifiers(btf, func_proto->type, NULL);
6072	offset += btf_type_is_ptr(t) ? 8 : roundup(t->size, 8);
6073	if (off < offset)
6074		return nr_args;
6075
6076	return nr_args + 1;
6077}
6078
6079static bool prog_args_trusted(const struct bpf_prog *prog)
6080{
6081	enum bpf_attach_type atype = prog->expected_attach_type;
6082
6083	switch (prog->type) {
6084	case BPF_PROG_TYPE_TRACING:
6085		return atype == BPF_TRACE_RAW_TP || atype == BPF_TRACE_ITER;
6086	case BPF_PROG_TYPE_LSM:
6087		return bpf_lsm_is_trusted(prog);
6088	case BPF_PROG_TYPE_STRUCT_OPS:
6089		return true;
6090	default:
6091		return false;
6092	}
6093}
6094
6095bool btf_ctx_access(int off, int size, enum bpf_access_type type,
6096		    const struct bpf_prog *prog,
6097		    struct bpf_insn_access_aux *info)
6098{
6099	const struct btf_type *t = prog->aux->attach_func_proto;
6100	struct bpf_prog *tgt_prog = prog->aux->dst_prog;
6101	struct btf *btf = bpf_prog_get_target_btf(prog);
6102	const char *tname = prog->aux->attach_func_name;
6103	struct bpf_verifier_log *log = info->log;
6104	const struct btf_param *args;
6105	const char *tag_value;
6106	u32 nr_args, arg;
6107	int i, ret;
6108
6109	if (off % 8) {
6110		bpf_log(log, "func '%s' offset %d is not multiple of 8\n",
6111			tname, off);
6112		return false;
6113	}
6114	arg = get_ctx_arg_idx(btf, t, off);
6115	args = (const struct btf_param *)(t + 1);
6116	/* if (t == NULL) Fall back to default BPF prog with
6117	 * MAX_BPF_FUNC_REG_ARGS u64 arguments.
6118	 */
6119	nr_args = t ? btf_type_vlen(t) : MAX_BPF_FUNC_REG_ARGS;
6120	if (prog->aux->attach_btf_trace) {
6121		/* skip first 'void *__data' argument in btf_trace_##name typedef */
6122		args++;
6123		nr_args--;
6124	}
6125
6126	if (arg > nr_args) {
6127		bpf_log(log, "func '%s' doesn't have %d-th argument\n",
6128			tname, arg + 1);
6129		return false;
6130	}
6131
6132	if (arg == nr_args) {
6133		switch (prog->expected_attach_type) {
6134		case BPF_LSM_CGROUP:
6135		case BPF_LSM_MAC:
6136		case BPF_TRACE_FEXIT:
6137			/* When LSM programs are attached to void LSM hooks
6138			 * they use FEXIT trampolines and when attached to
6139			 * int LSM hooks, they use MODIFY_RETURN trampolines.
6140			 *
6141			 * While the LSM programs are BPF_MODIFY_RETURN-like
6142			 * the check:
6143			 *
6144			 *	if (ret_type != 'int')
6145			 *		return -EINVAL;
6146			 *
6147			 * is _not_ done here. This is still safe as LSM hooks
6148			 * have only void and int return types.
6149			 */
6150			if (!t)
6151				return true;
6152			t = btf_type_by_id(btf, t->type);
6153			break;
6154		case BPF_MODIFY_RETURN:
6155			/* For now the BPF_MODIFY_RETURN can only be attached to
6156			 * functions that return an int.
6157			 */
6158			if (!t)
6159				return false;
6160
6161			t = btf_type_skip_modifiers(btf, t->type, NULL);
6162			if (!btf_type_is_small_int(t)) {
6163				bpf_log(log,
6164					"ret type %s not allowed for fmod_ret\n",
6165					btf_type_str(t));
6166				return false;
6167			}
6168			break;
6169		default:
6170			bpf_log(log, "func '%s' doesn't have %d-th argument\n",
6171				tname, arg + 1);
6172			return false;
6173		}
6174	} else {
6175		if (!t)
6176			/* Default prog with MAX_BPF_FUNC_REG_ARGS args */
6177			return true;
6178		t = btf_type_by_id(btf, args[arg].type);
6179	}
6180
6181	/* skip modifiers */
6182	while (btf_type_is_modifier(t))
6183		t = btf_type_by_id(btf, t->type);
6184	if (btf_type_is_small_int(t) || btf_is_any_enum(t) || __btf_type_is_struct(t))
6185		/* accessing a scalar */
6186		return true;
6187	if (!btf_type_is_ptr(t)) {
6188		bpf_log(log,
6189			"func '%s' arg%d '%s' has type %s. Only pointer access is allowed\n",
6190			tname, arg,
6191			__btf_name_by_offset(btf, t->name_off),
6192			btf_type_str(t));
6193		return false;
6194	}
6195
6196	/* check for PTR_TO_RDONLY_BUF_OR_NULL or PTR_TO_RDWR_BUF_OR_NULL */
6197	for (i = 0; i < prog->aux->ctx_arg_info_size; i++) {
6198		const struct bpf_ctx_arg_aux *ctx_arg_info = &prog->aux->ctx_arg_info[i];
6199		u32 type, flag;
6200
6201		type = base_type(ctx_arg_info->reg_type);
6202		flag = type_flag(ctx_arg_info->reg_type);
6203		if (ctx_arg_info->offset == off && type == PTR_TO_BUF &&
6204		    (flag & PTR_MAYBE_NULL)) {
6205			info->reg_type = ctx_arg_info->reg_type;
6206			return true;
6207		}
6208	}
6209
6210	if (t->type == 0)
6211		/* This is a pointer to void.
6212		 * It is the same as scalar from the verifier safety pov.
6213		 * No further pointer walking is allowed.
6214		 */
6215		return true;
6216
6217	if (is_int_ptr(btf, t))
6218		return true;
6219
6220	/* this is a pointer to another type */
6221	for (i = 0; i < prog->aux->ctx_arg_info_size; i++) {
6222		const struct bpf_ctx_arg_aux *ctx_arg_info = &prog->aux->ctx_arg_info[i];
6223
6224		if (ctx_arg_info->offset == off) {
6225			if (!ctx_arg_info->btf_id) {
6226				bpf_log(log,"invalid btf_id for context argument offset %u\n", off);
6227				return false;
6228			}
6229
6230			info->reg_type = ctx_arg_info->reg_type;
6231			info->btf = btf_vmlinux;
6232			info->btf_id = ctx_arg_info->btf_id;
6233			return true;
6234		}
6235	}
6236
6237	info->reg_type = PTR_TO_BTF_ID;
6238	if (prog_args_trusted(prog))
6239		info->reg_type |= PTR_TRUSTED;
6240
6241	if (tgt_prog) {
6242		enum bpf_prog_type tgt_type;
6243
6244		if (tgt_prog->type == BPF_PROG_TYPE_EXT)
6245			tgt_type = tgt_prog->aux->saved_dst_prog_type;
6246		else
6247			tgt_type = tgt_prog->type;
6248
6249		ret = btf_translate_to_vmlinux(log, btf, t, tgt_type, arg);
6250		if (ret > 0) {
6251			info->btf = btf_vmlinux;
6252			info->btf_id = ret;
6253			return true;
6254		} else {
6255			return false;
6256		}
6257	}
6258
6259	info->btf = btf;
6260	info->btf_id = t->type;
6261	t = btf_type_by_id(btf, t->type);
6262
6263	if (btf_type_is_type_tag(t)) {
6264		tag_value = __btf_name_by_offset(btf, t->name_off);
6265		if (strcmp(tag_value, "user") == 0)
6266			info->reg_type |= MEM_USER;
6267		if (strcmp(tag_value, "percpu") == 0)
6268			info->reg_type |= MEM_PERCPU;
6269	}
6270
6271	/* skip modifiers */
6272	while (btf_type_is_modifier(t)) {
6273		info->btf_id = t->type;
6274		t = btf_type_by_id(btf, t->type);
6275	}
6276	if (!btf_type_is_struct(t)) {
6277		bpf_log(log,
6278			"func '%s' arg%d type %s is not a struct\n",
6279			tname, arg, btf_type_str(t));
6280		return false;
6281	}
6282	bpf_log(log, "func '%s' arg%d has btf_id %d type %s '%s'\n",
6283		tname, arg, info->btf_id, btf_type_str(t),
6284		__btf_name_by_offset(btf, t->name_off));
6285	return true;
6286}
6287
6288enum bpf_struct_walk_result {
6289	/* < 0 error */
6290	WALK_SCALAR = 0,
6291	WALK_PTR,
6292	WALK_STRUCT,
6293};
6294
6295static int btf_struct_walk(struct bpf_verifier_log *log, const struct btf *btf,
6296			   const struct btf_type *t, int off, int size,
6297			   u32 *next_btf_id, enum bpf_type_flag *flag,
6298			   const char **field_name)
6299{
6300	u32 i, moff, mtrue_end, msize = 0, total_nelems = 0;
6301	const struct btf_type *mtype, *elem_type = NULL;
6302	const struct btf_member *member;
6303	const char *tname, *mname, *tag_value;
6304	u32 vlen, elem_id, mid;
6305
6306again:
6307	if (btf_type_is_modifier(t))
6308		t = btf_type_skip_modifiers(btf, t->type, NULL);
6309	tname = __btf_name_by_offset(btf, t->name_off);
6310	if (!btf_type_is_struct(t)) {
6311		bpf_log(log, "Type '%s' is not a struct\n", tname);
6312		return -EINVAL;
6313	}
6314
6315	vlen = btf_type_vlen(t);
6316	if (BTF_INFO_KIND(t->info) == BTF_KIND_UNION && vlen != 1 && !(*flag & PTR_UNTRUSTED))
6317		/*
6318		 * walking unions yields untrusted pointers
6319		 * with exception of __bpf_md_ptr and other
6320		 * unions with a single member
6321		 */
6322		*flag |= PTR_UNTRUSTED;
6323
6324	if (off + size > t->size) {
6325		/* If the last element is a variable size array, we may
6326		 * need to relax the rule.
6327		 */
6328		struct btf_array *array_elem;
6329
6330		if (vlen == 0)
6331			goto error;
6332
6333		member = btf_type_member(t) + vlen - 1;
6334		mtype = btf_type_skip_modifiers(btf, member->type,
6335						NULL);
6336		if (!btf_type_is_array(mtype))
6337			goto error;
6338
6339		array_elem = (struct btf_array *)(mtype + 1);
6340		if (array_elem->nelems != 0)
6341			goto error;
6342
6343		moff = __btf_member_bit_offset(t, member) / 8;
6344		if (off < moff)
6345			goto error;
6346
6347		/* allow structure and integer */
 
 
6348		t = btf_type_skip_modifiers(btf, array_elem->type,
6349					    NULL);
6350
6351		if (btf_type_is_int(t))
6352			return WALK_SCALAR;
6353
6354		if (!btf_type_is_struct(t))
6355			goto error;
6356
6357		off = (off - moff) % t->size;
6358		goto again;
6359
6360error:
6361		bpf_log(log, "access beyond struct %s at off %u size %u\n",
6362			tname, off, size);
6363		return -EACCES;
6364	}
6365
6366	for_each_member(i, t, member) {
6367		/* offset of the field in bytes */
6368		moff = __btf_member_bit_offset(t, member) / 8;
6369		if (off + size <= moff)
6370			/* won't find anything, field is already too far */
6371			break;
6372
6373		if (__btf_member_bitfield_size(t, member)) {
6374			u32 end_bit = __btf_member_bit_offset(t, member) +
6375				__btf_member_bitfield_size(t, member);
6376
6377			/* off <= moff instead of off == moff because clang
6378			 * does not generate a BTF member for anonymous
6379			 * bitfield like the ":16" here:
6380			 * struct {
6381			 *	int :16;
6382			 *	int x:8;
6383			 * };
6384			 */
6385			if (off <= moff &&
6386			    BITS_ROUNDUP_BYTES(end_bit) <= off + size)
6387				return WALK_SCALAR;
6388
6389			/* off may be accessing a following member
6390			 *
6391			 * or
6392			 *
6393			 * Doing partial access at either end of this
6394			 * bitfield.  Continue on this case also to
6395			 * treat it as not accessing this bitfield
6396			 * and eventually error out as field not
6397			 * found to keep it simple.
6398			 * It could be relaxed if there was a legit
6399			 * partial access case later.
6400			 */
6401			continue;
6402		}
6403
6404		/* In case of "off" is pointing to holes of a struct */
6405		if (off < moff)
6406			break;
6407
6408		/* type of the field */
6409		mid = member->type;
6410		mtype = btf_type_by_id(btf, member->type);
6411		mname = __btf_name_by_offset(btf, member->name_off);
6412
6413		mtype = __btf_resolve_size(btf, mtype, &msize,
6414					   &elem_type, &elem_id, &total_nelems,
6415					   &mid);
6416		if (IS_ERR(mtype)) {
6417			bpf_log(log, "field %s doesn't have size\n", mname);
6418			return -EFAULT;
6419		}
6420
6421		mtrue_end = moff + msize;
6422		if (off >= mtrue_end)
6423			/* no overlap with member, keep iterating */
6424			continue;
6425
6426		if (btf_type_is_array(mtype)) {
6427			u32 elem_idx;
6428
6429			/* __btf_resolve_size() above helps to
6430			 * linearize a multi-dimensional array.
6431			 *
6432			 * The logic here is treating an array
6433			 * in a struct as the following way:
6434			 *
6435			 * struct outer {
6436			 *	struct inner array[2][2];
6437			 * };
6438			 *
6439			 * looks like:
6440			 *
6441			 * struct outer {
6442			 *	struct inner array_elem0;
6443			 *	struct inner array_elem1;
6444			 *	struct inner array_elem2;
6445			 *	struct inner array_elem3;
6446			 * };
6447			 *
6448			 * When accessing outer->array[1][0], it moves
6449			 * moff to "array_elem2", set mtype to
6450			 * "struct inner", and msize also becomes
6451			 * sizeof(struct inner).  Then most of the
6452			 * remaining logic will fall through without
6453			 * caring the current member is an array or
6454			 * not.
6455			 *
6456			 * Unlike mtype/msize/moff, mtrue_end does not
6457			 * change.  The naming difference ("_true") tells
6458			 * that it is not always corresponding to
6459			 * the current mtype/msize/moff.
6460			 * It is the true end of the current
6461			 * member (i.e. array in this case).  That
6462			 * will allow an int array to be accessed like
6463			 * a scratch space,
6464			 * i.e. allow access beyond the size of
6465			 *      the array's element as long as it is
6466			 *      within the mtrue_end boundary.
6467			 */
6468
6469			/* skip empty array */
6470			if (moff == mtrue_end)
6471				continue;
6472
6473			msize /= total_nelems;
6474			elem_idx = (off - moff) / msize;
6475			moff += elem_idx * msize;
6476			mtype = elem_type;
6477			mid = elem_id;
6478		}
6479
6480		/* the 'off' we're looking for is either equal to start
6481		 * of this field or inside of this struct
6482		 */
6483		if (btf_type_is_struct(mtype)) {
6484			/* our field must be inside that union or struct */
6485			t = mtype;
6486
6487			/* return if the offset matches the member offset */
6488			if (off == moff) {
6489				*next_btf_id = mid;
6490				return WALK_STRUCT;
6491			}
6492
6493			/* adjust offset we're looking for */
6494			off -= moff;
6495			goto again;
6496		}
6497
6498		if (btf_type_is_ptr(mtype)) {
6499			const struct btf_type *stype, *t;
6500			enum bpf_type_flag tmp_flag = 0;
6501			u32 id;
6502
6503			if (msize != size || off != moff) {
6504				bpf_log(log,
6505					"cannot access ptr member %s with moff %u in struct %s with off %u size %u\n",
6506					mname, moff, tname, off, size);
6507				return -EACCES;
6508			}
6509
6510			/* check type tag */
6511			t = btf_type_by_id(btf, mtype->type);
6512			if (btf_type_is_type_tag(t)) {
6513				tag_value = __btf_name_by_offset(btf, t->name_off);
6514				/* check __user tag */
6515				if (strcmp(tag_value, "user") == 0)
6516					tmp_flag = MEM_USER;
6517				/* check __percpu tag */
6518				if (strcmp(tag_value, "percpu") == 0)
6519					tmp_flag = MEM_PERCPU;
6520				/* check __rcu tag */
6521				if (strcmp(tag_value, "rcu") == 0)
6522					tmp_flag = MEM_RCU;
6523			}
6524
6525			stype = btf_type_skip_modifiers(btf, mtype->type, &id);
6526			if (btf_type_is_struct(stype)) {
6527				*next_btf_id = id;
6528				*flag |= tmp_flag;
6529				if (field_name)
6530					*field_name = mname;
6531				return WALK_PTR;
6532			}
6533		}
6534
6535		/* Allow more flexible access within an int as long as
6536		 * it is within mtrue_end.
6537		 * Since mtrue_end could be the end of an array,
6538		 * that also allows using an array of int as a scratch
6539		 * space. e.g. skb->cb[].
6540		 */
6541		if (off + size > mtrue_end && !(*flag & PTR_UNTRUSTED)) {
6542			bpf_log(log,
6543				"access beyond the end of member %s (mend:%u) in struct %s with off %u size %u\n",
6544				mname, mtrue_end, tname, off, size);
6545			return -EACCES;
6546		}
6547
6548		return WALK_SCALAR;
6549	}
6550	bpf_log(log, "struct %s doesn't have field at offset %d\n", tname, off);
6551	return -EINVAL;
6552}
6553
6554int btf_struct_access(struct bpf_verifier_log *log,
6555		      const struct bpf_reg_state *reg,
6556		      int off, int size, enum bpf_access_type atype __maybe_unused,
6557		      u32 *next_btf_id, enum bpf_type_flag *flag,
6558		      const char **field_name)
6559{
6560	const struct btf *btf = reg->btf;
6561	enum bpf_type_flag tmp_flag = 0;
6562	const struct btf_type *t;
6563	u32 id = reg->btf_id;
6564	int err;
 
6565
6566	while (type_is_alloc(reg->type)) {
6567		struct btf_struct_meta *meta;
6568		struct btf_record *rec;
6569		int i;
6570
6571		meta = btf_find_struct_meta(btf, id);
6572		if (!meta)
6573			break;
6574		rec = meta->record;
6575		for (i = 0; i < rec->cnt; i++) {
6576			struct btf_field *field = &rec->fields[i];
6577			u32 offset = field->offset;
6578			if (off < offset + btf_field_type_size(field->type) && offset < off + size) {
6579				bpf_log(log,
6580					"direct access to %s is disallowed\n",
6581					btf_field_type_name(field->type));
6582				return -EACCES;
6583			}
6584		}
6585		break;
6586	}
6587
6588	t = btf_type_by_id(btf, id);
6589	do {
6590		err = btf_struct_walk(log, btf, t, off, size, &id, &tmp_flag, field_name);
6591
6592		switch (err) {
6593		case WALK_PTR:
6594			/* For local types, the destination register cannot
6595			 * become a pointer again.
6596			 */
6597			if (type_is_alloc(reg->type))
6598				return SCALAR_VALUE;
6599			/* If we found the pointer or scalar on t+off,
6600			 * we're done.
6601			 */
6602			*next_btf_id = id;
6603			*flag = tmp_flag;
6604			return PTR_TO_BTF_ID;
6605		case WALK_SCALAR:
6606			return SCALAR_VALUE;
6607		case WALK_STRUCT:
6608			/* We found nested struct, so continue the search
6609			 * by diving in it. At this point the offset is
6610			 * aligned with the new type, so set it to 0.
6611			 */
6612			t = btf_type_by_id(btf, id);
6613			off = 0;
6614			break;
6615		default:
6616			/* It's either error or unknown return value..
6617			 * scream and leave.
6618			 */
6619			if (WARN_ONCE(err > 0, "unknown btf_struct_walk return value"))
6620				return -EINVAL;
6621			return err;
6622		}
6623	} while (t);
6624
6625	return -EINVAL;
6626}
6627
6628/* Check that two BTF types, each specified as an BTF object + id, are exactly
6629 * the same. Trivial ID check is not enough due to module BTFs, because we can
6630 * end up with two different module BTFs, but IDs point to the common type in
6631 * vmlinux BTF.
6632 */
6633bool btf_types_are_same(const struct btf *btf1, u32 id1,
6634			const struct btf *btf2, u32 id2)
6635{
6636	if (id1 != id2)
6637		return false;
6638	if (btf1 == btf2)
6639		return true;
6640	return btf_type_by_id(btf1, id1) == btf_type_by_id(btf2, id2);
6641}
6642
6643bool btf_struct_ids_match(struct bpf_verifier_log *log,
6644			  const struct btf *btf, u32 id, int off,
6645			  const struct btf *need_btf, u32 need_type_id,
6646			  bool strict)
6647{
6648	const struct btf_type *type;
6649	enum bpf_type_flag flag = 0;
6650	int err;
6651
6652	/* Are we already done? */
6653	if (off == 0 && btf_types_are_same(btf, id, need_btf, need_type_id))
6654		return true;
6655	/* In case of strict type match, we do not walk struct, the top level
6656	 * type match must succeed. When strict is true, off should have already
6657	 * been 0.
6658	 */
6659	if (strict)
6660		return false;
6661again:
6662	type = btf_type_by_id(btf, id);
6663	if (!type)
6664		return false;
6665	err = btf_struct_walk(log, btf, type, off, 1, &id, &flag, NULL);
6666	if (err != WALK_STRUCT)
6667		return false;
6668
6669	/* We found nested struct object. If it matches
6670	 * the requested ID, we're done. Otherwise let's
6671	 * continue the search with offset 0 in the new
6672	 * type.
6673	 */
6674	if (!btf_types_are_same(btf, id, need_btf, need_type_id)) {
6675		off = 0;
6676		goto again;
6677	}
6678
6679	return true;
6680}
6681
6682static int __get_type_size(struct btf *btf, u32 btf_id,
6683			   const struct btf_type **ret_type)
6684{
6685	const struct btf_type *t;
6686
6687	*ret_type = btf_type_by_id(btf, 0);
6688	if (!btf_id)
6689		/* void */
6690		return 0;
6691	t = btf_type_by_id(btf, btf_id);
6692	while (t && btf_type_is_modifier(t))
6693		t = btf_type_by_id(btf, t->type);
6694	if (!t)
 
6695		return -EINVAL;
6696	*ret_type = t;
6697	if (btf_type_is_ptr(t))
6698		/* kernel size of pointer. Not BPF's size of pointer*/
6699		return sizeof(void *);
6700	if (btf_type_is_int(t) || btf_is_any_enum(t) || __btf_type_is_struct(t))
6701		return t->size;
 
6702	return -EINVAL;
6703}
6704
6705static u8 __get_type_fmodel_flags(const struct btf_type *t)
6706{
6707	u8 flags = 0;
6708
6709	if (__btf_type_is_struct(t))
6710		flags |= BTF_FMODEL_STRUCT_ARG;
6711	if (btf_type_is_signed_int(t))
6712		flags |= BTF_FMODEL_SIGNED_ARG;
6713
6714	return flags;
6715}
6716
6717int btf_distill_func_proto(struct bpf_verifier_log *log,
6718			   struct btf *btf,
6719			   const struct btf_type *func,
6720			   const char *tname,
6721			   struct btf_func_model *m)
6722{
6723	const struct btf_param *args;
6724	const struct btf_type *t;
6725	u32 i, nargs;
6726	int ret;
6727
6728	if (!func) {
6729		/* BTF function prototype doesn't match the verifier types.
6730		 * Fall back to MAX_BPF_FUNC_REG_ARGS u64 args.
6731		 */
6732		for (i = 0; i < MAX_BPF_FUNC_REG_ARGS; i++) {
6733			m->arg_size[i] = 8;
6734			m->arg_flags[i] = 0;
6735		}
6736		m->ret_size = 8;
6737		m->ret_flags = 0;
6738		m->nr_args = MAX_BPF_FUNC_REG_ARGS;
6739		return 0;
6740	}
6741	args = (const struct btf_param *)(func + 1);
6742	nargs = btf_type_vlen(func);
6743	if (nargs > MAX_BPF_FUNC_ARGS) {
6744		bpf_log(log,
6745			"The function %s has %d arguments. Too many.\n",
6746			tname, nargs);
6747		return -EINVAL;
6748	}
6749	ret = __get_type_size(btf, func->type, &t);
6750	if (ret < 0 || __btf_type_is_struct(t)) {
6751		bpf_log(log,
6752			"The function %s return type %s is unsupported.\n",
6753			tname, btf_type_str(t));
6754		return -EINVAL;
6755	}
6756	m->ret_size = ret;
6757	m->ret_flags = __get_type_fmodel_flags(t);
6758
6759	for (i = 0; i < nargs; i++) {
6760		if (i == nargs - 1 && args[i].type == 0) {
6761			bpf_log(log,
6762				"The function %s with variable args is unsupported.\n",
6763				tname);
6764			return -EINVAL;
6765		}
6766		ret = __get_type_size(btf, args[i].type, &t);
6767
6768		/* No support of struct argument size greater than 16 bytes */
6769		if (ret < 0 || ret > 16) {
6770			bpf_log(log,
6771				"The function %s arg%d type %s is unsupported.\n",
6772				tname, i, btf_type_str(t));
6773			return -EINVAL;
6774		}
6775		if (ret == 0) {
6776			bpf_log(log,
6777				"The function %s has malformed void argument.\n",
6778				tname);
6779			return -EINVAL;
6780		}
6781		m->arg_size[i] = ret;
6782		m->arg_flags[i] = __get_type_fmodel_flags(t);
6783	}
6784	m->nr_args = nargs;
6785	return 0;
6786}
6787
6788/* Compare BTFs of two functions assuming only scalars and pointers to context.
6789 * t1 points to BTF_KIND_FUNC in btf1
6790 * t2 points to BTF_KIND_FUNC in btf2
6791 * Returns:
6792 * EINVAL - function prototype mismatch
6793 * EFAULT - verifier bug
6794 * 0 - 99% match. The last 1% is validated by the verifier.
6795 */
6796static int btf_check_func_type_match(struct bpf_verifier_log *log,
6797				     struct btf *btf1, const struct btf_type *t1,
6798				     struct btf *btf2, const struct btf_type *t2)
6799{
6800	const struct btf_param *args1, *args2;
6801	const char *fn1, *fn2, *s1, *s2;
6802	u32 nargs1, nargs2, i;
6803
6804	fn1 = btf_name_by_offset(btf1, t1->name_off);
6805	fn2 = btf_name_by_offset(btf2, t2->name_off);
6806
6807	if (btf_func_linkage(t1) != BTF_FUNC_GLOBAL) {
6808		bpf_log(log, "%s() is not a global function\n", fn1);
6809		return -EINVAL;
6810	}
6811	if (btf_func_linkage(t2) != BTF_FUNC_GLOBAL) {
6812		bpf_log(log, "%s() is not a global function\n", fn2);
6813		return -EINVAL;
6814	}
6815
6816	t1 = btf_type_by_id(btf1, t1->type);
6817	if (!t1 || !btf_type_is_func_proto(t1))
6818		return -EFAULT;
6819	t2 = btf_type_by_id(btf2, t2->type);
6820	if (!t2 || !btf_type_is_func_proto(t2))
6821		return -EFAULT;
6822
6823	args1 = (const struct btf_param *)(t1 + 1);
6824	nargs1 = btf_type_vlen(t1);
6825	args2 = (const struct btf_param *)(t2 + 1);
6826	nargs2 = btf_type_vlen(t2);
6827
6828	if (nargs1 != nargs2) {
6829		bpf_log(log, "%s() has %d args while %s() has %d args\n",
6830			fn1, nargs1, fn2, nargs2);
6831		return -EINVAL;
6832	}
6833
6834	t1 = btf_type_skip_modifiers(btf1, t1->type, NULL);
6835	t2 = btf_type_skip_modifiers(btf2, t2->type, NULL);
6836	if (t1->info != t2->info) {
6837		bpf_log(log,
6838			"Return type %s of %s() doesn't match type %s of %s()\n",
6839			btf_type_str(t1), fn1,
6840			btf_type_str(t2), fn2);
6841		return -EINVAL;
6842	}
6843
6844	for (i = 0; i < nargs1; i++) {
6845		t1 = btf_type_skip_modifiers(btf1, args1[i].type, NULL);
6846		t2 = btf_type_skip_modifiers(btf2, args2[i].type, NULL);
6847
6848		if (t1->info != t2->info) {
6849			bpf_log(log, "arg%d in %s() is %s while %s() has %s\n",
6850				i, fn1, btf_type_str(t1),
6851				fn2, btf_type_str(t2));
6852			return -EINVAL;
6853		}
6854		if (btf_type_has_size(t1) && t1->size != t2->size) {
6855			bpf_log(log,
6856				"arg%d in %s() has size %d while %s() has %d\n",
6857				i, fn1, t1->size,
6858				fn2, t2->size);
6859			return -EINVAL;
6860		}
6861
6862		/* global functions are validated with scalars and pointers
6863		 * to context only. And only global functions can be replaced.
6864		 * Hence type check only those types.
6865		 */
6866		if (btf_type_is_int(t1) || btf_is_any_enum(t1))
6867			continue;
6868		if (!btf_type_is_ptr(t1)) {
6869			bpf_log(log,
6870				"arg%d in %s() has unrecognized type\n",
6871				i, fn1);
6872			return -EINVAL;
6873		}
6874		t1 = btf_type_skip_modifiers(btf1, t1->type, NULL);
6875		t2 = btf_type_skip_modifiers(btf2, t2->type, NULL);
6876		if (!btf_type_is_struct(t1)) {
6877			bpf_log(log,
6878				"arg%d in %s() is not a pointer to context\n",
6879				i, fn1);
6880			return -EINVAL;
6881		}
6882		if (!btf_type_is_struct(t2)) {
6883			bpf_log(log,
6884				"arg%d in %s() is not a pointer to context\n",
6885				i, fn2);
6886			return -EINVAL;
6887		}
6888		/* This is an optional check to make program writing easier.
6889		 * Compare names of structs and report an error to the user.
6890		 * btf_prepare_func_args() already checked that t2 struct
6891		 * is a context type. btf_prepare_func_args() will check
6892		 * later that t1 struct is a context type as well.
6893		 */
6894		s1 = btf_name_by_offset(btf1, t1->name_off);
6895		s2 = btf_name_by_offset(btf2, t2->name_off);
6896		if (strcmp(s1, s2)) {
6897			bpf_log(log,
6898				"arg%d %s(struct %s *) doesn't match %s(struct %s *)\n",
6899				i, fn1, s1, fn2, s2);
6900			return -EINVAL;
6901		}
6902	}
6903	return 0;
6904}
6905
6906/* Compare BTFs of given program with BTF of target program */
6907int btf_check_type_match(struct bpf_verifier_log *log, const struct bpf_prog *prog,
6908			 struct btf *btf2, const struct btf_type *t2)
6909{
6910	struct btf *btf1 = prog->aux->btf;
6911	const struct btf_type *t1;
6912	u32 btf_id = 0;
6913
6914	if (!prog->aux->func_info) {
6915		bpf_log(log, "Program extension requires BTF\n");
6916		return -EINVAL;
6917	}
6918
6919	btf_id = prog->aux->func_info[0].type_id;
6920	if (!btf_id)
6921		return -EFAULT;
6922
6923	t1 = btf_type_by_id(btf1, btf_id);
6924	if (!t1 || !btf_type_is_func(t1))
6925		return -EFAULT;
6926
6927	return btf_check_func_type_match(log, btf1, t1, btf2, t2);
6928}
6929
6930static bool btf_is_dynptr_ptr(const struct btf *btf, const struct btf_type *t)
 
 
 
 
 
 
 
 
 
 
 
6931{
6932	const char *name;
 
 
 
 
6933
6934	t = btf_type_by_id(btf, t->type); /* skip PTR */
 
 
 
 
 
 
 
 
 
6935
6936	while (btf_type_is_modifier(t))
6937		t = btf_type_by_id(btf, t->type);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
6938
6939	/* allow either struct or struct forward declaration */
6940	if (btf_type_is_struct(t) ||
6941	    (btf_type_is_fwd(t) && btf_type_kflag(t) == 0)) {
6942		name = btf_str_by_offset(btf, t->name_off);
6943		return name && strcmp(name, "bpf_dynptr") == 0;
6944	}
6945
6946	return false;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
6947}
6948
6949/* Process BTF of a function to produce high-level expectation of function
6950 * arguments (like ARG_PTR_TO_CTX, or ARG_PTR_TO_MEM, etc). This information
6951 * is cached in subprog info for reuse.
6952 * Returns:
6953 * EFAULT - there is a verifier bug. Abort verification.
6954 * EINVAL - cannot convert BTF.
6955 * 0 - Successfully processed BTF and constructed argument expectations.
 
6956 */
6957int btf_prepare_func_args(struct bpf_verifier_env *env, int subprog)
 
6958{
6959	bool is_global = subprog_aux(env, subprog)->linkage == BTF_FUNC_GLOBAL;
6960	struct bpf_subprog_info *sub = subprog_info(env, subprog);
6961	struct bpf_verifier_log *log = &env->log;
6962	struct bpf_prog *prog = env->prog;
6963	enum bpf_prog_type prog_type = prog->type;
6964	struct btf *btf = prog->aux->btf;
6965	const struct btf_param *args;
6966	const struct btf_type *t, *ref_t, *fn_t;
6967	u32 i, nargs, btf_id;
6968	const char *tname;
6969
6970	if (sub->args_cached)
6971		return 0;
6972
6973	if (!prog->aux->func_info) {
6974		bpf_log(log, "Verifier bug\n");
6975		return -EFAULT;
6976	}
6977
6978	btf_id = prog->aux->func_info[subprog].type_id;
6979	if (!btf_id) {
6980		if (!is_global) /* not fatal for static funcs */
6981			return -EINVAL;
6982		bpf_log(log, "Global functions need valid BTF\n");
6983		return -EFAULT;
6984	}
6985
6986	fn_t = btf_type_by_id(btf, btf_id);
6987	if (!fn_t || !btf_type_is_func(fn_t)) {
6988		/* These checks were already done by the verifier while loading
6989		 * struct bpf_func_info
6990		 */
6991		bpf_log(log, "BTF of func#%d doesn't point to KIND_FUNC\n",
6992			subprog);
6993		return -EFAULT;
6994	}
6995	tname = btf_name_by_offset(btf, fn_t->name_off);
 
 
 
 
6996
6997	if (prog->aux->func_info_aux[subprog].unreliable) {
6998		bpf_log(log, "Verifier bug in function %s()\n", tname);
6999		return -EFAULT;
7000	}
7001	if (prog_type == BPF_PROG_TYPE_EXT)
7002		prog_type = prog->aux->dst_prog->type;
7003
7004	t = btf_type_by_id(btf, fn_t->type);
7005	if (!t || !btf_type_is_func_proto(t)) {
7006		bpf_log(log, "Invalid type of function %s()\n", tname);
7007		return -EFAULT;
7008	}
7009	args = (const struct btf_param *)(t + 1);
7010	nargs = btf_type_vlen(t);
7011	if (nargs > MAX_BPF_FUNC_REG_ARGS) {
7012		bpf_log(log, "Global function %s() with %d > %d args. Buggy compiler.\n",
7013			tname, nargs, MAX_BPF_FUNC_REG_ARGS);
7014		return -EINVAL;
7015	}
7016	/* check that function returns int, exception cb also requires this */
7017	t = btf_type_by_id(btf, t->type);
7018	while (btf_type_is_modifier(t))
7019		t = btf_type_by_id(btf, t->type);
7020	if (!btf_type_is_int(t) && !btf_is_any_enum(t)) {
7021		bpf_log(log,
7022			"Global function %s() doesn't return scalar. Only those are supported.\n",
7023			tname);
7024		return -EINVAL;
7025	}
7026	/* Convert BTF function arguments into verifier types.
7027	 * Only PTR_TO_CTX and SCALAR are supported atm.
7028	 */
7029	for (i = 0; i < nargs; i++) {
7030		bool is_nonnull = false;
7031		const char *tag;
7032
7033		t = btf_type_by_id(btf, args[i].type);
7034
7035		tag = btf_find_decl_tag_value(btf, fn_t, i, "arg:");
7036		if (IS_ERR(tag) && PTR_ERR(tag) == -ENOENT) {
7037			tag = NULL;
7038		} else if (IS_ERR(tag)) {
7039			bpf_log(log, "arg#%d type's tag fetching failure: %ld\n", i, PTR_ERR(tag));
7040			return PTR_ERR(tag);
7041		}
7042		/* 'arg:<tag>' decl_tag takes precedence over derivation of
7043		 * register type from BTF type itself
7044		 */
7045		if (tag) {
7046			/* disallow arg tags in static subprogs */
7047			if (!is_global) {
7048				bpf_log(log, "arg#%d type tag is not supported in static functions\n", i);
7049				return -EOPNOTSUPP;
7050			}
7051			if (strcmp(tag, "ctx") == 0) {
7052				sub->args[i].arg_type = ARG_PTR_TO_CTX;
7053				continue;
7054			}
7055			if (strcmp(tag, "nonnull") == 0)
7056				is_nonnull = true;
7057		}
7058
7059		while (btf_type_is_modifier(t))
7060			t = btf_type_by_id(btf, t->type);
7061		if (btf_type_is_int(t) || btf_is_any_enum(t)) {
7062			sub->args[i].arg_type = ARG_ANYTHING;
7063			continue;
7064		}
7065		if (btf_type_is_ptr(t) && btf_get_prog_ctx_type(log, btf, t, prog_type, i)) {
7066			sub->args[i].arg_type = ARG_PTR_TO_CTX;
7067			continue;
7068		}
7069		if (btf_type_is_ptr(t) && btf_is_dynptr_ptr(btf, t)) {
7070			sub->args[i].arg_type = ARG_PTR_TO_DYNPTR | MEM_RDONLY;
7071			continue;
7072		}
7073		if (is_global && btf_type_is_ptr(t)) {
7074			u32 mem_size;
7075
7076			t = btf_type_skip_modifiers(btf, t->type, NULL);
7077			ref_t = btf_resolve_size(btf, t, &mem_size);
 
7078			if (IS_ERR(ref_t)) {
7079				bpf_log(log,
7080				    "arg#%d reference type('%s %s') size cannot be determined: %ld\n",
7081				    i, btf_type_str(t), btf_name_by_offset(btf, t->name_off),
7082					PTR_ERR(ref_t));
7083				return -EINVAL;
7084			}
7085
7086			sub->args[i].arg_type = is_nonnull ? ARG_PTR_TO_MEM : ARG_PTR_TO_MEM_OR_NULL;
7087			sub->args[i].mem_size = mem_size;
 
7088			continue;
7089		}
7090		if (is_nonnull) {
7091			bpf_log(log, "arg#%d marked as non-null, but is not a pointer type\n", i);
7092			return -EINVAL;
7093		}
7094		bpf_log(log, "Arg#%d type %s in %s() is not supported yet.\n",
7095			i, btf_type_str(t), tname);
7096		return -EINVAL;
7097	}
7098
7099	for (i = 0; i < nargs; i++) {
7100		const char *tag;
7101
7102		if (sub->args[i].arg_type != ARG_PTR_TO_CTX)
7103			continue;
7104
7105		/* check if arg has "arg:ctx" tag */
7106		t = btf_type_by_id(btf, args[i].type);
7107		tag = btf_find_decl_tag_value(btf, fn_t, i, "arg:");
7108		if (IS_ERR_OR_NULL(tag) || strcmp(tag, "ctx") != 0)
7109			continue;
7110
7111		if (btf_validate_prog_ctx_type(log, btf, t, i, prog_type,
7112					       prog->expected_attach_type))
7113			return -EINVAL;
7114	}
7115
7116	sub->arg_cnt = nargs;
7117	sub->args_cached = true;
7118
7119	return 0;
7120}
7121
7122static void btf_type_show(const struct btf *btf, u32 type_id, void *obj,
7123			  struct btf_show *show)
7124{
7125	const struct btf_type *t = btf_type_by_id(btf, type_id);
7126
7127	show->btf = btf;
7128	memset(&show->state, 0, sizeof(show->state));
7129	memset(&show->obj, 0, sizeof(show->obj));
7130
7131	btf_type_ops(t)->show(btf, t, type_id, obj, 0, show);
7132}
7133
7134static void btf_seq_show(struct btf_show *show, const char *fmt,
7135			 va_list args)
7136{
7137	seq_vprintf((struct seq_file *)show->target, fmt, args);
7138}
7139
7140int btf_type_seq_show_flags(const struct btf *btf, u32 type_id,
7141			    void *obj, struct seq_file *m, u64 flags)
7142{
7143	struct btf_show sseq;
7144
7145	sseq.target = m;
7146	sseq.showfn = btf_seq_show;
7147	sseq.flags = flags;
7148
7149	btf_type_show(btf, type_id, obj, &sseq);
7150
7151	return sseq.state.status;
7152}
7153
7154void btf_type_seq_show(const struct btf *btf, u32 type_id, void *obj,
7155		       struct seq_file *m)
7156{
7157	(void) btf_type_seq_show_flags(btf, type_id, obj, m,
7158				       BTF_SHOW_NONAME | BTF_SHOW_COMPACT |
7159				       BTF_SHOW_ZERO | BTF_SHOW_UNSAFE);
7160}
7161
7162struct btf_show_snprintf {
7163	struct btf_show show;
7164	int len_left;		/* space left in string */
7165	int len;		/* length we would have written */
7166};
7167
7168static void btf_snprintf_show(struct btf_show *show, const char *fmt,
7169			      va_list args)
7170{
7171	struct btf_show_snprintf *ssnprintf = (struct btf_show_snprintf *)show;
7172	int len;
7173
7174	len = vsnprintf(show->target, ssnprintf->len_left, fmt, args);
7175
7176	if (len < 0) {
7177		ssnprintf->len_left = 0;
7178		ssnprintf->len = len;
7179	} else if (len >= ssnprintf->len_left) {
7180		/* no space, drive on to get length we would have written */
7181		ssnprintf->len_left = 0;
7182		ssnprintf->len += len;
7183	} else {
7184		ssnprintf->len_left -= len;
7185		ssnprintf->len += len;
7186		show->target += len;
7187	}
7188}
7189
7190int btf_type_snprintf_show(const struct btf *btf, u32 type_id, void *obj,
7191			   char *buf, int len, u64 flags)
7192{
7193	struct btf_show_snprintf ssnprintf;
7194
7195	ssnprintf.show.target = buf;
7196	ssnprintf.show.flags = flags;
7197	ssnprintf.show.showfn = btf_snprintf_show;
7198	ssnprintf.len_left = len;
7199	ssnprintf.len = 0;
7200
7201	btf_type_show(btf, type_id, obj, (struct btf_show *)&ssnprintf);
7202
7203	/* If we encountered an error, return it. */
7204	if (ssnprintf.show.state.status)
7205		return ssnprintf.show.state.status;
7206
7207	/* Otherwise return length we would have written */
7208	return ssnprintf.len;
7209}
7210
7211#ifdef CONFIG_PROC_FS
7212static void bpf_btf_show_fdinfo(struct seq_file *m, struct file *filp)
7213{
7214	const struct btf *btf = filp->private_data;
7215
7216	seq_printf(m, "btf_id:\t%u\n", btf->id);
7217}
7218#endif
7219
7220static int btf_release(struct inode *inode, struct file *filp)
7221{
7222	btf_put(filp->private_data);
7223	return 0;
7224}
7225
7226const struct file_operations btf_fops = {
7227#ifdef CONFIG_PROC_FS
7228	.show_fdinfo	= bpf_btf_show_fdinfo,
7229#endif
7230	.release	= btf_release,
7231};
7232
7233static int __btf_new_fd(struct btf *btf)
7234{
7235	return anon_inode_getfd("btf", &btf_fops, btf, O_RDONLY | O_CLOEXEC);
7236}
7237
7238int btf_new_fd(const union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size)
7239{
7240	struct btf *btf;
7241	int ret;
7242
7243	btf = btf_parse(attr, uattr, uattr_size);
 
 
 
7244	if (IS_ERR(btf))
7245		return PTR_ERR(btf);
7246
7247	ret = btf_alloc_id(btf);
7248	if (ret) {
7249		btf_free(btf);
7250		return ret;
7251	}
7252
7253	/*
7254	 * The BTF ID is published to the userspace.
7255	 * All BTF free must go through call_rcu() from
7256	 * now on (i.e. free by calling btf_put()).
7257	 */
7258
7259	ret = __btf_new_fd(btf);
7260	if (ret < 0)
7261		btf_put(btf);
7262
7263	return ret;
7264}
7265
7266struct btf *btf_get_by_fd(int fd)
7267{
7268	struct btf *btf;
7269	struct fd f;
7270
7271	f = fdget(fd);
7272
7273	if (!f.file)
7274		return ERR_PTR(-EBADF);
7275
7276	if (f.file->f_op != &btf_fops) {
7277		fdput(f);
7278		return ERR_PTR(-EINVAL);
7279	}
7280
7281	btf = f.file->private_data;
7282	refcount_inc(&btf->refcnt);
7283	fdput(f);
7284
7285	return btf;
7286}
7287
7288int btf_get_info_by_fd(const struct btf *btf,
7289		       const union bpf_attr *attr,
7290		       union bpf_attr __user *uattr)
7291{
7292	struct bpf_btf_info __user *uinfo;
7293	struct bpf_btf_info info;
7294	u32 info_copy, btf_copy;
7295	void __user *ubtf;
7296	char __user *uname;
7297	u32 uinfo_len, uname_len, name_len;
7298	int ret = 0;
7299
7300	uinfo = u64_to_user_ptr(attr->info.info);
7301	uinfo_len = attr->info.info_len;
7302
7303	info_copy = min_t(u32, uinfo_len, sizeof(info));
7304	memset(&info, 0, sizeof(info));
7305	if (copy_from_user(&info, uinfo, info_copy))
7306		return -EFAULT;
7307
7308	info.id = btf->id;
7309	ubtf = u64_to_user_ptr(info.btf);
7310	btf_copy = min_t(u32, btf->data_size, info.btf_size);
7311	if (copy_to_user(ubtf, btf->data, btf_copy))
7312		return -EFAULT;
7313	info.btf_size = btf->data_size;
7314
7315	info.kernel_btf = btf->kernel_btf;
7316
7317	uname = u64_to_user_ptr(info.name);
7318	uname_len = info.name_len;
7319	if (!uname ^ !uname_len)
7320		return -EINVAL;
7321
7322	name_len = strlen(btf->name);
7323	info.name_len = name_len;
7324
7325	if (uname) {
7326		if (uname_len >= name_len + 1) {
7327			if (copy_to_user(uname, btf->name, name_len + 1))
7328				return -EFAULT;
7329		} else {
7330			char zero = '\0';
7331
7332			if (copy_to_user(uname, btf->name, uname_len - 1))
7333				return -EFAULT;
7334			if (put_user(zero, uname + uname_len - 1))
7335				return -EFAULT;
7336			/* let user-space know about too short buffer */
7337			ret = -ENOSPC;
7338		}
7339	}
7340
7341	if (copy_to_user(uinfo, &info, info_copy) ||
7342	    put_user(info_copy, &uattr->info.info_len))
7343		return -EFAULT;
7344
7345	return ret;
7346}
7347
7348int btf_get_fd_by_id(u32 id)
7349{
7350	struct btf *btf;
7351	int fd;
7352
7353	rcu_read_lock();
7354	btf = idr_find(&btf_idr, id);
7355	if (!btf || !refcount_inc_not_zero(&btf->refcnt))
7356		btf = ERR_PTR(-ENOENT);
7357	rcu_read_unlock();
7358
7359	if (IS_ERR(btf))
7360		return PTR_ERR(btf);
7361
7362	fd = __btf_new_fd(btf);
7363	if (fd < 0)
7364		btf_put(btf);
7365
7366	return fd;
7367}
7368
7369u32 btf_obj_id(const struct btf *btf)
7370{
7371	return btf->id;
7372}
7373
7374bool btf_is_kernel(const struct btf *btf)
7375{
7376	return btf->kernel_btf;
7377}
7378
7379bool btf_is_module(const struct btf *btf)
7380{
7381	return btf->kernel_btf && strcmp(btf->name, "vmlinux") != 0;
7382}
7383
7384enum {
7385	BTF_MODULE_F_LIVE = (1 << 0),
7386};
 
 
 
 
 
 
 
 
7387
7388#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
7389struct btf_module {
7390	struct list_head list;
7391	struct module *module;
7392	struct btf *btf;
7393	struct bin_attribute *sysfs_attr;
7394	int flags;
7395};
7396
7397static LIST_HEAD(btf_modules);
7398static DEFINE_MUTEX(btf_module_mutex);
7399
7400static ssize_t
7401btf_module_read(struct file *file, struct kobject *kobj,
7402		struct bin_attribute *bin_attr,
7403		char *buf, loff_t off, size_t len)
7404{
7405	const struct btf *btf = bin_attr->private;
7406
7407	memcpy(buf, btf->data + off, len);
7408	return len;
7409}
7410
7411static void purge_cand_cache(struct btf *btf);
7412
7413static int btf_module_notify(struct notifier_block *nb, unsigned long op,
7414			     void *module)
7415{
7416	struct btf_module *btf_mod, *tmp;
7417	struct module *mod = module;
7418	struct btf *btf;
7419	int err = 0;
7420
7421	if (mod->btf_data_size == 0 ||
7422	    (op != MODULE_STATE_COMING && op != MODULE_STATE_LIVE &&
7423	     op != MODULE_STATE_GOING))
7424		goto out;
7425
7426	switch (op) {
7427	case MODULE_STATE_COMING:
7428		btf_mod = kzalloc(sizeof(*btf_mod), GFP_KERNEL);
7429		if (!btf_mod) {
7430			err = -ENOMEM;
7431			goto out;
7432		}
7433		btf = btf_parse_module(mod->name, mod->btf_data, mod->btf_data_size);
7434		if (IS_ERR(btf)) {
 
 
7435			kfree(btf_mod);
7436			if (!IS_ENABLED(CONFIG_MODULE_ALLOW_BTF_MISMATCH)) {
7437				pr_warn("failed to validate module [%s] BTF: %ld\n",
7438					mod->name, PTR_ERR(btf));
7439				err = PTR_ERR(btf);
7440			} else {
7441				pr_warn_once("Kernel module BTF mismatch detected, BTF debug info may be unavailable for some modules\n");
7442			}
7443			goto out;
7444		}
7445		err = btf_alloc_id(btf);
7446		if (err) {
7447			btf_free(btf);
7448			kfree(btf_mod);
7449			goto out;
7450		}
7451
7452		purge_cand_cache(NULL);
7453		mutex_lock(&btf_module_mutex);
7454		btf_mod->module = module;
7455		btf_mod->btf = btf;
7456		list_add(&btf_mod->list, &btf_modules);
7457		mutex_unlock(&btf_module_mutex);
7458
7459		if (IS_ENABLED(CONFIG_SYSFS)) {
7460			struct bin_attribute *attr;
7461
7462			attr = kzalloc(sizeof(*attr), GFP_KERNEL);
7463			if (!attr)
7464				goto out;
7465
7466			sysfs_bin_attr_init(attr);
7467			attr->attr.name = btf->name;
7468			attr->attr.mode = 0444;
7469			attr->size = btf->data_size;
7470			attr->private = btf;
7471			attr->read = btf_module_read;
7472
7473			err = sysfs_create_bin_file(btf_kobj, attr);
7474			if (err) {
7475				pr_warn("failed to register module [%s] BTF in sysfs: %d\n",
7476					mod->name, err);
7477				kfree(attr);
7478				err = 0;
7479				goto out;
7480			}
7481
7482			btf_mod->sysfs_attr = attr;
7483		}
7484
7485		break;
7486	case MODULE_STATE_LIVE:
7487		mutex_lock(&btf_module_mutex);
7488		list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
7489			if (btf_mod->module != module)
7490				continue;
7491
7492			btf_mod->flags |= BTF_MODULE_F_LIVE;
7493			break;
7494		}
7495		mutex_unlock(&btf_module_mutex);
7496		break;
7497	case MODULE_STATE_GOING:
7498		mutex_lock(&btf_module_mutex);
7499		list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
7500			if (btf_mod->module != module)
7501				continue;
7502
7503			list_del(&btf_mod->list);
7504			if (btf_mod->sysfs_attr)
7505				sysfs_remove_bin_file(btf_kobj, btf_mod->sysfs_attr);
7506			purge_cand_cache(btf_mod->btf);
7507			btf_put(btf_mod->btf);
7508			kfree(btf_mod->sysfs_attr);
7509			kfree(btf_mod);
7510			break;
7511		}
7512		mutex_unlock(&btf_module_mutex);
7513		break;
7514	}
7515out:
7516	return notifier_from_errno(err);
7517}
7518
7519static struct notifier_block btf_module_nb = {
7520	.notifier_call = btf_module_notify,
7521};
7522
7523static int __init btf_module_init(void)
7524{
7525	register_module_notifier(&btf_module_nb);
7526	return 0;
7527}
7528
7529fs_initcall(btf_module_init);
7530#endif /* CONFIG_DEBUG_INFO_BTF_MODULES */
7531
7532struct module *btf_try_get_module(const struct btf *btf)
7533{
7534	struct module *res = NULL;
7535#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
7536	struct btf_module *btf_mod, *tmp;
7537
7538	mutex_lock(&btf_module_mutex);
7539	list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
7540		if (btf_mod->btf != btf)
7541			continue;
7542
7543		/* We must only consider module whose __init routine has
7544		 * finished, hence we must check for BTF_MODULE_F_LIVE flag,
7545		 * which is set from the notifier callback for
7546		 * MODULE_STATE_LIVE.
7547		 */
7548		if ((btf_mod->flags & BTF_MODULE_F_LIVE) && try_module_get(btf_mod->module))
7549			res = btf_mod->module;
7550
7551		break;
7552	}
7553	mutex_unlock(&btf_module_mutex);
7554#endif
7555
7556	return res;
7557}
7558
7559/* Returns struct btf corresponding to the struct module.
7560 * This function can return NULL or ERR_PTR.
7561 */
7562static struct btf *btf_get_module_btf(const struct module *module)
7563{
7564#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
7565	struct btf_module *btf_mod, *tmp;
7566#endif
7567	struct btf *btf = NULL;
7568
7569	if (!module) {
7570		btf = bpf_get_btf_vmlinux();
7571		if (!IS_ERR_OR_NULL(btf))
7572			btf_get(btf);
7573		return btf;
7574	}
7575
7576#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
7577	mutex_lock(&btf_module_mutex);
7578	list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
7579		if (btf_mod->module != module)
7580			continue;
7581
7582		btf_get(btf_mod->btf);
7583		btf = btf_mod->btf;
7584		break;
7585	}
7586	mutex_unlock(&btf_module_mutex);
7587#endif
7588
7589	return btf;
7590}
7591
7592BPF_CALL_4(bpf_btf_find_by_name_kind, char *, name, int, name_sz, u32, kind, int, flags)
7593{
7594	struct btf *btf = NULL;
7595	int btf_obj_fd = 0;
7596	long ret;
7597
7598	if (flags)
7599		return -EINVAL;
7600
7601	if (name_sz <= 1 || name[name_sz - 1])
7602		return -EINVAL;
7603
7604	ret = bpf_find_btf_id(name, kind, &btf);
7605	if (ret > 0 && btf_is_module(btf)) {
7606		btf_obj_fd = __btf_new_fd(btf);
7607		if (btf_obj_fd < 0) {
7608			btf_put(btf);
7609			return btf_obj_fd;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
7610		}
7611		return ret | (((u64)btf_obj_fd) << 32);
7612	}
7613	if (ret > 0)
7614		btf_put(btf);
7615	return ret;
7616}
7617
7618const struct bpf_func_proto bpf_btf_find_by_name_kind_proto = {
7619	.func		= bpf_btf_find_by_name_kind,
7620	.gpl_only	= false,
7621	.ret_type	= RET_INTEGER,
7622	.arg1_type	= ARG_PTR_TO_MEM | MEM_RDONLY,
7623	.arg2_type	= ARG_CONST_SIZE,
7624	.arg3_type	= ARG_ANYTHING,
7625	.arg4_type	= ARG_ANYTHING,
7626};
7627
7628BTF_ID_LIST_GLOBAL(btf_tracing_ids, MAX_BTF_TRACING_TYPE)
7629#define BTF_TRACING_TYPE(name, type) BTF_ID(struct, type)
7630BTF_TRACING_TYPE_xxx
7631#undef BTF_TRACING_TYPE
7632
7633static int btf_check_iter_kfuncs(struct btf *btf, const char *func_name,
7634				 const struct btf_type *func, u32 func_flags)
7635{
7636	u32 flags = func_flags & (KF_ITER_NEW | KF_ITER_NEXT | KF_ITER_DESTROY);
7637	const char *name, *sfx, *iter_name;
7638	const struct btf_param *arg;
7639	const struct btf_type *t;
7640	char exp_name[128];
7641	u32 nr_args;
7642
7643	/* exactly one of KF_ITER_{NEW,NEXT,DESTROY} can be set */
7644	if (!flags || (flags & (flags - 1)))
7645		return -EINVAL;
7646
7647	/* any BPF iter kfunc should have `struct bpf_iter_<type> *` first arg */
7648	nr_args = btf_type_vlen(func);
7649	if (nr_args < 1)
7650		return -EINVAL;
7651
7652	arg = &btf_params(func)[0];
7653	t = btf_type_skip_modifiers(btf, arg->type, NULL);
7654	if (!t || !btf_type_is_ptr(t))
7655		return -EINVAL;
7656	t = btf_type_skip_modifiers(btf, t->type, NULL);
7657	if (!t || !__btf_type_is_struct(t))
7658		return -EINVAL;
7659
7660	name = btf_name_by_offset(btf, t->name_off);
7661	if (!name || strncmp(name, ITER_PREFIX, sizeof(ITER_PREFIX) - 1))
7662		return -EINVAL;
7663
7664	/* sizeof(struct bpf_iter_<type>) should be a multiple of 8 to
7665	 * fit nicely in stack slots
7666	 */
7667	if (t->size == 0 || (t->size % 8))
7668		return -EINVAL;
7669
7670	/* validate bpf_iter_<type>_{new,next,destroy}(struct bpf_iter_<type> *)
7671	 * naming pattern
7672	 */
7673	iter_name = name + sizeof(ITER_PREFIX) - 1;
7674	if (flags & KF_ITER_NEW)
7675		sfx = "new";
7676	else if (flags & KF_ITER_NEXT)
7677		sfx = "next";
7678	else /* (flags & KF_ITER_DESTROY) */
7679		sfx = "destroy";
7680
7681	snprintf(exp_name, sizeof(exp_name), "bpf_iter_%s_%s", iter_name, sfx);
7682	if (strcmp(func_name, exp_name))
7683		return -EINVAL;
7684
7685	/* only iter constructor should have extra arguments */
7686	if (!(flags & KF_ITER_NEW) && nr_args != 1)
7687		return -EINVAL;
7688
7689	if (flags & KF_ITER_NEXT) {
7690		/* bpf_iter_<type>_next() should return pointer */
7691		t = btf_type_skip_modifiers(btf, func->type, NULL);
7692		if (!t || !btf_type_is_ptr(t))
7693			return -EINVAL;
7694	}
7695
7696	if (flags & KF_ITER_DESTROY) {
7697		/* bpf_iter_<type>_destroy() should return void */
7698		t = btf_type_by_id(btf, func->type);
7699		if (!t || !btf_type_is_void(t))
7700			return -EINVAL;
7701	}
7702
7703	return 0;
7704}
7705
7706static int btf_check_kfunc_protos(struct btf *btf, u32 func_id, u32 func_flags)
7707{
7708	const struct btf_type *func;
7709	const char *func_name;
7710	int err;
7711
7712	/* any kfunc should be FUNC -> FUNC_PROTO */
7713	func = btf_type_by_id(btf, func_id);
7714	if (!func || !btf_type_is_func(func))
7715		return -EINVAL;
7716
7717	/* sanity check kfunc name */
7718	func_name = btf_name_by_offset(btf, func->name_off);
7719	if (!func_name || !func_name[0])
7720		return -EINVAL;
7721
7722	func = btf_type_by_id(btf, func->type);
7723	if (!func || !btf_type_is_func_proto(func))
7724		return -EINVAL;
7725
7726	if (func_flags & (KF_ITER_NEW | KF_ITER_NEXT | KF_ITER_DESTROY)) {
7727		err = btf_check_iter_kfuncs(btf, func_name, func, func_flags);
7728		if (err)
7729			return err;
7730	}
7731
7732	return 0;
7733}
7734
7735/* Kernel Function (kfunc) BTF ID set registration API */
7736
7737static int btf_populate_kfunc_set(struct btf *btf, enum btf_kfunc_hook hook,
7738				  const struct btf_kfunc_id_set *kset)
7739{
7740	struct btf_kfunc_hook_filter *hook_filter;
7741	struct btf_id_set8 *add_set = kset->set;
7742	bool vmlinux_set = !btf_is_module(btf);
7743	bool add_filter = !!kset->filter;
7744	struct btf_kfunc_set_tab *tab;
7745	struct btf_id_set8 *set;
7746	u32 set_cnt;
7747	int ret;
7748
7749	if (hook >= BTF_KFUNC_HOOK_MAX) {
7750		ret = -EINVAL;
7751		goto end;
7752	}
7753
7754	if (!add_set->cnt)
7755		return 0;
7756
7757	tab = btf->kfunc_set_tab;
7758
7759	if (tab && add_filter) {
7760		u32 i;
7761
7762		hook_filter = &tab->hook_filters[hook];
7763		for (i = 0; i < hook_filter->nr_filters; i++) {
7764			if (hook_filter->filters[i] == kset->filter) {
7765				add_filter = false;
7766				break;
7767			}
7768		}
7769
7770		if (add_filter && hook_filter->nr_filters == BTF_KFUNC_FILTER_MAX_CNT) {
7771			ret = -E2BIG;
7772			goto end;
7773		}
7774	}
7775
7776	if (!tab) {
7777		tab = kzalloc(sizeof(*tab), GFP_KERNEL | __GFP_NOWARN);
7778		if (!tab)
7779			return -ENOMEM;
7780		btf->kfunc_set_tab = tab;
7781	}
7782
7783	set = tab->sets[hook];
7784	/* Warn when register_btf_kfunc_id_set is called twice for the same hook
7785	 * for module sets.
7786	 */
7787	if (WARN_ON_ONCE(set && !vmlinux_set)) {
7788		ret = -EINVAL;
7789		goto end;
7790	}
7791
7792	/* We don't need to allocate, concatenate, and sort module sets, because
7793	 * only one is allowed per hook. Hence, we can directly assign the
7794	 * pointer and return.
7795	 */
7796	if (!vmlinux_set) {
7797		tab->sets[hook] = add_set;
7798		goto do_add_filter;
7799	}
7800
7801	/* In case of vmlinux sets, there may be more than one set being
7802	 * registered per hook. To create a unified set, we allocate a new set
7803	 * and concatenate all individual sets being registered. While each set
7804	 * is individually sorted, they may become unsorted when concatenated,
7805	 * hence re-sorting the final set again is required to make binary
7806	 * searching the set using btf_id_set8_contains function work.
7807	 */
7808	set_cnt = set ? set->cnt : 0;
7809
7810	if (set_cnt > U32_MAX - add_set->cnt) {
7811		ret = -EOVERFLOW;
7812		goto end;
7813	}
7814
7815	if (set_cnt + add_set->cnt > BTF_KFUNC_SET_MAX_CNT) {
7816		ret = -E2BIG;
7817		goto end;
7818	}
7819
7820	/* Grow set */
7821	set = krealloc(tab->sets[hook],
7822		       offsetof(struct btf_id_set8, pairs[set_cnt + add_set->cnt]),
7823		       GFP_KERNEL | __GFP_NOWARN);
7824	if (!set) {
7825		ret = -ENOMEM;
7826		goto end;
7827	}
7828
7829	/* For newly allocated set, initialize set->cnt to 0 */
7830	if (!tab->sets[hook])
7831		set->cnt = 0;
7832	tab->sets[hook] = set;
7833
7834	/* Concatenate the two sets */
7835	memcpy(set->pairs + set->cnt, add_set->pairs, add_set->cnt * sizeof(set->pairs[0]));
7836	set->cnt += add_set->cnt;
7837
7838	sort(set->pairs, set->cnt, sizeof(set->pairs[0]), btf_id_cmp_func, NULL);
7839
7840do_add_filter:
7841	if (add_filter) {
7842		hook_filter = &tab->hook_filters[hook];
7843		hook_filter->filters[hook_filter->nr_filters++] = kset->filter;
7844	}
7845	return 0;
7846end:
7847	btf_free_kfunc_set_tab(btf);
7848	return ret;
7849}
7850
7851static u32 *__btf_kfunc_id_set_contains(const struct btf *btf,
7852					enum btf_kfunc_hook hook,
7853					u32 kfunc_btf_id,
7854					const struct bpf_prog *prog)
7855{
7856	struct btf_kfunc_hook_filter *hook_filter;
7857	struct btf_id_set8 *set;
7858	u32 *id, i;
7859
7860	if (hook >= BTF_KFUNC_HOOK_MAX)
7861		return NULL;
7862	if (!btf->kfunc_set_tab)
7863		return NULL;
7864	hook_filter = &btf->kfunc_set_tab->hook_filters[hook];
7865	for (i = 0; i < hook_filter->nr_filters; i++) {
7866		if (hook_filter->filters[i](prog, kfunc_btf_id))
7867			return NULL;
7868	}
7869	set = btf->kfunc_set_tab->sets[hook];
7870	if (!set)
7871		return NULL;
7872	id = btf_id_set8_contains(set, kfunc_btf_id);
7873	if (!id)
7874		return NULL;
7875	/* The flags for BTF ID are located next to it */
7876	return id + 1;
7877}
7878
7879static int bpf_prog_type_to_kfunc_hook(enum bpf_prog_type prog_type)
7880{
7881	switch (prog_type) {
7882	case BPF_PROG_TYPE_UNSPEC:
7883		return BTF_KFUNC_HOOK_COMMON;
7884	case BPF_PROG_TYPE_XDP:
7885		return BTF_KFUNC_HOOK_XDP;
7886	case BPF_PROG_TYPE_SCHED_CLS:
7887		return BTF_KFUNC_HOOK_TC;
7888	case BPF_PROG_TYPE_STRUCT_OPS:
7889		return BTF_KFUNC_HOOK_STRUCT_OPS;
7890	case BPF_PROG_TYPE_TRACING:
7891	case BPF_PROG_TYPE_LSM:
7892		return BTF_KFUNC_HOOK_TRACING;
7893	case BPF_PROG_TYPE_SYSCALL:
7894		return BTF_KFUNC_HOOK_SYSCALL;
7895	case BPF_PROG_TYPE_CGROUP_SKB:
7896	case BPF_PROG_TYPE_CGROUP_SOCK_ADDR:
7897		return BTF_KFUNC_HOOK_CGROUP_SKB;
7898	case BPF_PROG_TYPE_SCHED_ACT:
7899		return BTF_KFUNC_HOOK_SCHED_ACT;
7900	case BPF_PROG_TYPE_SK_SKB:
7901		return BTF_KFUNC_HOOK_SK_SKB;
7902	case BPF_PROG_TYPE_SOCKET_FILTER:
7903		return BTF_KFUNC_HOOK_SOCKET_FILTER;
7904	case BPF_PROG_TYPE_LWT_OUT:
7905	case BPF_PROG_TYPE_LWT_IN:
7906	case BPF_PROG_TYPE_LWT_XMIT:
7907	case BPF_PROG_TYPE_LWT_SEG6LOCAL:
7908		return BTF_KFUNC_HOOK_LWT;
7909	case BPF_PROG_TYPE_NETFILTER:
7910		return BTF_KFUNC_HOOK_NETFILTER;
7911	default:
7912		return BTF_KFUNC_HOOK_MAX;
7913	}
7914}
7915
7916/* Caution:
7917 * Reference to the module (obtained using btf_try_get_module) corresponding to
7918 * the struct btf *MUST* be held when calling this function from verifier
7919 * context. This is usually true as we stash references in prog's kfunc_btf_tab;
7920 * keeping the reference for the duration of the call provides the necessary
7921 * protection for looking up a well-formed btf->kfunc_set_tab.
7922 */
7923u32 *btf_kfunc_id_set_contains(const struct btf *btf,
7924			       u32 kfunc_btf_id,
7925			       const struct bpf_prog *prog)
7926{
7927	enum bpf_prog_type prog_type = resolve_prog_type(prog);
7928	enum btf_kfunc_hook hook;
7929	u32 *kfunc_flags;
7930
7931	kfunc_flags = __btf_kfunc_id_set_contains(btf, BTF_KFUNC_HOOK_COMMON, kfunc_btf_id, prog);
7932	if (kfunc_flags)
7933		return kfunc_flags;
7934
7935	hook = bpf_prog_type_to_kfunc_hook(prog_type);
7936	return __btf_kfunc_id_set_contains(btf, hook, kfunc_btf_id, prog);
7937}
7938
7939u32 *btf_kfunc_is_modify_return(const struct btf *btf, u32 kfunc_btf_id,
7940				const struct bpf_prog *prog)
7941{
7942	return __btf_kfunc_id_set_contains(btf, BTF_KFUNC_HOOK_FMODRET, kfunc_btf_id, prog);
7943}
7944
7945static int __register_btf_kfunc_id_set(enum btf_kfunc_hook hook,
7946				       const struct btf_kfunc_id_set *kset)
7947{
7948	struct btf *btf;
7949	int ret, i;
7950
7951	btf = btf_get_module_btf(kset->owner);
7952	if (!btf) {
7953		if (!kset->owner && IS_ENABLED(CONFIG_DEBUG_INFO_BTF)) {
7954			pr_err("missing vmlinux BTF, cannot register kfuncs\n");
7955			return -ENOENT;
7956		}
7957		if (kset->owner && IS_ENABLED(CONFIG_DEBUG_INFO_BTF_MODULES))
7958			pr_warn("missing module BTF, cannot register kfuncs\n");
7959		return 0;
7960	}
7961	if (IS_ERR(btf))
7962		return PTR_ERR(btf);
7963
7964	for (i = 0; i < kset->set->cnt; i++) {
7965		ret = btf_check_kfunc_protos(btf, kset->set->pairs[i].id,
7966					     kset->set->pairs[i].flags);
7967		if (ret)
7968			goto err_out;
7969	}
7970
7971	ret = btf_populate_kfunc_set(btf, hook, kset);
7972
7973err_out:
7974	btf_put(btf);
7975	return ret;
7976}
7977
7978/* This function must be invoked only from initcalls/module init functions */
7979int register_btf_kfunc_id_set(enum bpf_prog_type prog_type,
7980			      const struct btf_kfunc_id_set *kset)
7981{
7982	enum btf_kfunc_hook hook;
7983
7984	hook = bpf_prog_type_to_kfunc_hook(prog_type);
7985	return __register_btf_kfunc_id_set(hook, kset);
7986}
7987EXPORT_SYMBOL_GPL(register_btf_kfunc_id_set);
7988
7989/* This function must be invoked only from initcalls/module init functions */
7990int register_btf_fmodret_id_set(const struct btf_kfunc_id_set *kset)
7991{
7992	return __register_btf_kfunc_id_set(BTF_KFUNC_HOOK_FMODRET, kset);
7993}
7994EXPORT_SYMBOL_GPL(register_btf_fmodret_id_set);
7995
7996s32 btf_find_dtor_kfunc(struct btf *btf, u32 btf_id)
7997{
7998	struct btf_id_dtor_kfunc_tab *tab = btf->dtor_kfunc_tab;
7999	struct btf_id_dtor_kfunc *dtor;
8000
8001	if (!tab)
8002		return -ENOENT;
8003	/* Even though the size of tab->dtors[0] is > sizeof(u32), we only need
8004	 * to compare the first u32 with btf_id, so we can reuse btf_id_cmp_func.
8005	 */
8006	BUILD_BUG_ON(offsetof(struct btf_id_dtor_kfunc, btf_id) != 0);
8007	dtor = bsearch(&btf_id, tab->dtors, tab->cnt, sizeof(tab->dtors[0]), btf_id_cmp_func);
8008	if (!dtor)
8009		return -ENOENT;
8010	return dtor->kfunc_btf_id;
8011}
8012
8013static int btf_check_dtor_kfuncs(struct btf *btf, const struct btf_id_dtor_kfunc *dtors, u32 cnt)
8014{
8015	const struct btf_type *dtor_func, *dtor_func_proto, *t;
8016	const struct btf_param *args;
8017	s32 dtor_btf_id;
8018	u32 nr_args, i;
8019
8020	for (i = 0; i < cnt; i++) {
8021		dtor_btf_id = dtors[i].kfunc_btf_id;
8022
8023		dtor_func = btf_type_by_id(btf, dtor_btf_id);
8024		if (!dtor_func || !btf_type_is_func(dtor_func))
8025			return -EINVAL;
8026
8027		dtor_func_proto = btf_type_by_id(btf, dtor_func->type);
8028		if (!dtor_func_proto || !btf_type_is_func_proto(dtor_func_proto))
8029			return -EINVAL;
8030
8031		/* Make sure the prototype of the destructor kfunc is 'void func(type *)' */
8032		t = btf_type_by_id(btf, dtor_func_proto->type);
8033		if (!t || !btf_type_is_void(t))
8034			return -EINVAL;
8035
8036		nr_args = btf_type_vlen(dtor_func_proto);
8037		if (nr_args != 1)
8038			return -EINVAL;
8039		args = btf_params(dtor_func_proto);
8040		t = btf_type_by_id(btf, args[0].type);
8041		/* Allow any pointer type, as width on targets Linux supports
8042		 * will be same for all pointer types (i.e. sizeof(void *))
8043		 */
8044		if (!t || !btf_type_is_ptr(t))
8045			return -EINVAL;
8046	}
8047	return 0;
8048}
8049
8050/* This function must be invoked only from initcalls/module init functions */
8051int register_btf_id_dtor_kfuncs(const struct btf_id_dtor_kfunc *dtors, u32 add_cnt,
8052				struct module *owner)
8053{
8054	struct btf_id_dtor_kfunc_tab *tab;
8055	struct btf *btf;
8056	u32 tab_cnt;
8057	int ret;
8058
8059	btf = btf_get_module_btf(owner);
8060	if (!btf) {
8061		if (!owner && IS_ENABLED(CONFIG_DEBUG_INFO_BTF)) {
8062			pr_err("missing vmlinux BTF, cannot register dtor kfuncs\n");
8063			return -ENOENT;
8064		}
8065		if (owner && IS_ENABLED(CONFIG_DEBUG_INFO_BTF_MODULES)) {
8066			pr_err("missing module BTF, cannot register dtor kfuncs\n");
8067			return -ENOENT;
8068		}
8069		return 0;
8070	}
8071	if (IS_ERR(btf))
8072		return PTR_ERR(btf);
8073
8074	if (add_cnt >= BTF_DTOR_KFUNC_MAX_CNT) {
8075		pr_err("cannot register more than %d kfunc destructors\n", BTF_DTOR_KFUNC_MAX_CNT);
8076		ret = -E2BIG;
8077		goto end;
8078	}
8079
8080	/* Ensure that the prototype of dtor kfuncs being registered is sane */
8081	ret = btf_check_dtor_kfuncs(btf, dtors, add_cnt);
8082	if (ret < 0)
8083		goto end;
8084
8085	tab = btf->dtor_kfunc_tab;
8086	/* Only one call allowed for modules */
8087	if (WARN_ON_ONCE(tab && btf_is_module(btf))) {
8088		ret = -EINVAL;
8089		goto end;
8090	}
8091
8092	tab_cnt = tab ? tab->cnt : 0;
8093	if (tab_cnt > U32_MAX - add_cnt) {
8094		ret = -EOVERFLOW;
8095		goto end;
8096	}
8097	if (tab_cnt + add_cnt >= BTF_DTOR_KFUNC_MAX_CNT) {
8098		pr_err("cannot register more than %d kfunc destructors\n", BTF_DTOR_KFUNC_MAX_CNT);
8099		ret = -E2BIG;
8100		goto end;
8101	}
8102
8103	tab = krealloc(btf->dtor_kfunc_tab,
8104		       offsetof(struct btf_id_dtor_kfunc_tab, dtors[tab_cnt + add_cnt]),
8105		       GFP_KERNEL | __GFP_NOWARN);
8106	if (!tab) {
8107		ret = -ENOMEM;
8108		goto end;
8109	}
8110
8111	if (!btf->dtor_kfunc_tab)
8112		tab->cnt = 0;
8113	btf->dtor_kfunc_tab = tab;
8114
8115	memcpy(tab->dtors + tab->cnt, dtors, add_cnt * sizeof(tab->dtors[0]));
8116	tab->cnt += add_cnt;
8117
8118	sort(tab->dtors, tab->cnt, sizeof(tab->dtors[0]), btf_id_cmp_func, NULL);
8119
8120end:
8121	if (ret)
8122		btf_free_dtor_kfunc_tab(btf);
8123	btf_put(btf);
8124	return ret;
8125}
8126EXPORT_SYMBOL_GPL(register_btf_id_dtor_kfuncs);
8127
8128#define MAX_TYPES_ARE_COMPAT_DEPTH 2
8129
8130/* Check local and target types for compatibility. This check is used for
8131 * type-based CO-RE relocations and follow slightly different rules than
8132 * field-based relocations. This function assumes that root types were already
8133 * checked for name match. Beyond that initial root-level name check, names
8134 * are completely ignored. Compatibility rules are as follows:
8135 *   - any two STRUCTs/UNIONs/FWDs/ENUMs/INTs/ENUM64s are considered compatible, but
8136 *     kind should match for local and target types (i.e., STRUCT is not
8137 *     compatible with UNION);
8138 *   - for ENUMs/ENUM64s, the size is ignored;
8139 *   - for INT, size and signedness are ignored;
8140 *   - for ARRAY, dimensionality is ignored, element types are checked for
8141 *     compatibility recursively;
8142 *   - CONST/VOLATILE/RESTRICT modifiers are ignored;
8143 *   - TYPEDEFs/PTRs are compatible if types they pointing to are compatible;
8144 *   - FUNC_PROTOs are compatible if they have compatible signature: same
8145 *     number of input args and compatible return and argument types.
8146 * These rules are not set in stone and probably will be adjusted as we get
8147 * more experience with using BPF CO-RE relocations.
8148 */
8149int bpf_core_types_are_compat(const struct btf *local_btf, __u32 local_id,
8150			      const struct btf *targ_btf, __u32 targ_id)
8151{
8152	return __bpf_core_types_are_compat(local_btf, local_id, targ_btf, targ_id,
8153					   MAX_TYPES_ARE_COMPAT_DEPTH);
8154}
8155
8156#define MAX_TYPES_MATCH_DEPTH 2
8157
8158int bpf_core_types_match(const struct btf *local_btf, u32 local_id,
8159			 const struct btf *targ_btf, u32 targ_id)
8160{
8161	return __bpf_core_types_match(local_btf, local_id, targ_btf, targ_id, false,
8162				      MAX_TYPES_MATCH_DEPTH);
8163}
8164
8165static bool bpf_core_is_flavor_sep(const char *s)
8166{
8167	/* check X___Y name pattern, where X and Y are not underscores */
8168	return s[0] != '_' &&				      /* X */
8169	       s[1] == '_' && s[2] == '_' && s[3] == '_' &&   /* ___ */
8170	       s[4] != '_';				      /* Y */
8171}
8172
8173size_t bpf_core_essential_name_len(const char *name)
8174{
8175	size_t n = strlen(name);
8176	int i;
8177
8178	for (i = n - 5; i >= 0; i--) {
8179		if (bpf_core_is_flavor_sep(name + i))
8180			return i + 1;
8181	}
8182	return n;
8183}
8184
8185struct bpf_cand_cache {
8186	const char *name;
8187	u32 name_len;
8188	u16 kind;
8189	u16 cnt;
8190	struct {
8191		const struct btf *btf;
8192		u32 id;
8193	} cands[];
8194};
8195
8196static void bpf_free_cands(struct bpf_cand_cache *cands)
8197{
8198	if (!cands->cnt)
8199		/* empty candidate array was allocated on stack */
8200		return;
8201	kfree(cands);
8202}
8203
8204static void bpf_free_cands_from_cache(struct bpf_cand_cache *cands)
8205{
8206	kfree(cands->name);
8207	kfree(cands);
8208}
8209
8210#define VMLINUX_CAND_CACHE_SIZE 31
8211static struct bpf_cand_cache *vmlinux_cand_cache[VMLINUX_CAND_CACHE_SIZE];
8212
8213#define MODULE_CAND_CACHE_SIZE 31
8214static struct bpf_cand_cache *module_cand_cache[MODULE_CAND_CACHE_SIZE];
8215
8216static DEFINE_MUTEX(cand_cache_mutex);
8217
8218static void __print_cand_cache(struct bpf_verifier_log *log,
8219			       struct bpf_cand_cache **cache,
8220			       int cache_size)
8221{
8222	struct bpf_cand_cache *cc;
8223	int i, j;
8224
8225	for (i = 0; i < cache_size; i++) {
8226		cc = cache[i];
8227		if (!cc)
8228			continue;
8229		bpf_log(log, "[%d]%s(", i, cc->name);
8230		for (j = 0; j < cc->cnt; j++) {
8231			bpf_log(log, "%d", cc->cands[j].id);
8232			if (j < cc->cnt - 1)
8233				bpf_log(log, " ");
8234		}
8235		bpf_log(log, "), ");
8236	}
8237}
8238
8239static void print_cand_cache(struct bpf_verifier_log *log)
8240{
8241	mutex_lock(&cand_cache_mutex);
8242	bpf_log(log, "vmlinux_cand_cache:");
8243	__print_cand_cache(log, vmlinux_cand_cache, VMLINUX_CAND_CACHE_SIZE);
8244	bpf_log(log, "\nmodule_cand_cache:");
8245	__print_cand_cache(log, module_cand_cache, MODULE_CAND_CACHE_SIZE);
8246	bpf_log(log, "\n");
8247	mutex_unlock(&cand_cache_mutex);
8248}
8249
8250static u32 hash_cands(struct bpf_cand_cache *cands)
8251{
8252	return jhash(cands->name, cands->name_len, 0);
8253}
8254
8255static struct bpf_cand_cache *check_cand_cache(struct bpf_cand_cache *cands,
8256					       struct bpf_cand_cache **cache,
8257					       int cache_size)
8258{
8259	struct bpf_cand_cache *cc = cache[hash_cands(cands) % cache_size];
8260
8261	if (cc && cc->name_len == cands->name_len &&
8262	    !strncmp(cc->name, cands->name, cands->name_len))
8263		return cc;
8264	return NULL;
8265}
8266
8267static size_t sizeof_cands(int cnt)
8268{
8269	return offsetof(struct bpf_cand_cache, cands[cnt]);
8270}
8271
8272static struct bpf_cand_cache *populate_cand_cache(struct bpf_cand_cache *cands,
8273						  struct bpf_cand_cache **cache,
8274						  int cache_size)
8275{
8276	struct bpf_cand_cache **cc = &cache[hash_cands(cands) % cache_size], *new_cands;
8277
8278	if (*cc) {
8279		bpf_free_cands_from_cache(*cc);
8280		*cc = NULL;
8281	}
8282	new_cands = kmemdup(cands, sizeof_cands(cands->cnt), GFP_KERNEL);
8283	if (!new_cands) {
8284		bpf_free_cands(cands);
8285		return ERR_PTR(-ENOMEM);
8286	}
8287	/* strdup the name, since it will stay in cache.
8288	 * the cands->name points to strings in prog's BTF and the prog can be unloaded.
8289	 */
8290	new_cands->name = kmemdup_nul(cands->name, cands->name_len, GFP_KERNEL);
8291	bpf_free_cands(cands);
8292	if (!new_cands->name) {
8293		kfree(new_cands);
8294		return ERR_PTR(-ENOMEM);
8295	}
8296	*cc = new_cands;
8297	return new_cands;
8298}
8299
8300#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
8301static void __purge_cand_cache(struct btf *btf, struct bpf_cand_cache **cache,
8302			       int cache_size)
8303{
8304	struct bpf_cand_cache *cc;
8305	int i, j;
8306
8307	for (i = 0; i < cache_size; i++) {
8308		cc = cache[i];
8309		if (!cc)
8310			continue;
8311		if (!btf) {
8312			/* when new module is loaded purge all of module_cand_cache,
8313			 * since new module might have candidates with the name
8314			 * that matches cached cands.
8315			 */
8316			bpf_free_cands_from_cache(cc);
8317			cache[i] = NULL;
8318			continue;
8319		}
8320		/* when module is unloaded purge cache entries
8321		 * that match module's btf
8322		 */
8323		for (j = 0; j < cc->cnt; j++)
8324			if (cc->cands[j].btf == btf) {
8325				bpf_free_cands_from_cache(cc);
8326				cache[i] = NULL;
8327				break;
8328			}
8329	}
8330
8331}
8332
8333static void purge_cand_cache(struct btf *btf)
8334{
8335	mutex_lock(&cand_cache_mutex);
8336	__purge_cand_cache(btf, module_cand_cache, MODULE_CAND_CACHE_SIZE);
8337	mutex_unlock(&cand_cache_mutex);
8338}
8339#endif
8340
8341static struct bpf_cand_cache *
8342bpf_core_add_cands(struct bpf_cand_cache *cands, const struct btf *targ_btf,
8343		   int targ_start_id)
8344{
8345	struct bpf_cand_cache *new_cands;
8346	const struct btf_type *t;
8347	const char *targ_name;
8348	size_t targ_essent_len;
8349	int n, i;
8350
8351	n = btf_nr_types(targ_btf);
8352	for (i = targ_start_id; i < n; i++) {
8353		t = btf_type_by_id(targ_btf, i);
8354		if (btf_kind(t) != cands->kind)
8355			continue;
8356
8357		targ_name = btf_name_by_offset(targ_btf, t->name_off);
8358		if (!targ_name)
8359			continue;
8360
8361		/* the resched point is before strncmp to make sure that search
8362		 * for non-existing name will have a chance to schedule().
8363		 */
8364		cond_resched();
8365
8366		if (strncmp(cands->name, targ_name, cands->name_len) != 0)
8367			continue;
8368
8369		targ_essent_len = bpf_core_essential_name_len(targ_name);
8370		if (targ_essent_len != cands->name_len)
8371			continue;
8372
8373		/* most of the time there is only one candidate for a given kind+name pair */
8374		new_cands = kmalloc(sizeof_cands(cands->cnt + 1), GFP_KERNEL);
8375		if (!new_cands) {
8376			bpf_free_cands(cands);
8377			return ERR_PTR(-ENOMEM);
8378		}
8379
8380		memcpy(new_cands, cands, sizeof_cands(cands->cnt));
8381		bpf_free_cands(cands);
8382		cands = new_cands;
8383		cands->cands[cands->cnt].btf = targ_btf;
8384		cands->cands[cands->cnt].id = i;
8385		cands->cnt++;
8386	}
8387	return cands;
8388}
8389
8390static struct bpf_cand_cache *
8391bpf_core_find_cands(struct bpf_core_ctx *ctx, u32 local_type_id)
8392{
8393	struct bpf_cand_cache *cands, *cc, local_cand = {};
8394	const struct btf *local_btf = ctx->btf;
8395	const struct btf_type *local_type;
8396	const struct btf *main_btf;
8397	size_t local_essent_len;
8398	struct btf *mod_btf;
8399	const char *name;
8400	int id;
8401
8402	main_btf = bpf_get_btf_vmlinux();
8403	if (IS_ERR(main_btf))
8404		return ERR_CAST(main_btf);
8405	if (!main_btf)
8406		return ERR_PTR(-EINVAL);
8407
8408	local_type = btf_type_by_id(local_btf, local_type_id);
8409	if (!local_type)
8410		return ERR_PTR(-EINVAL);
8411
8412	name = btf_name_by_offset(local_btf, local_type->name_off);
8413	if (str_is_empty(name))
8414		return ERR_PTR(-EINVAL);
8415	local_essent_len = bpf_core_essential_name_len(name);
8416
8417	cands = &local_cand;
8418	cands->name = name;
8419	cands->kind = btf_kind(local_type);
8420	cands->name_len = local_essent_len;
8421
8422	cc = check_cand_cache(cands, vmlinux_cand_cache, VMLINUX_CAND_CACHE_SIZE);
8423	/* cands is a pointer to stack here */
8424	if (cc) {
8425		if (cc->cnt)
8426			return cc;
8427		goto check_modules;
8428	}
8429
8430	/* Attempt to find target candidates in vmlinux BTF first */
8431	cands = bpf_core_add_cands(cands, main_btf, 1);
8432	if (IS_ERR(cands))
8433		return ERR_CAST(cands);
8434
8435	/* cands is a pointer to kmalloced memory here if cands->cnt > 0 */
8436
8437	/* populate cache even when cands->cnt == 0 */
8438	cc = populate_cand_cache(cands, vmlinux_cand_cache, VMLINUX_CAND_CACHE_SIZE);
8439	if (IS_ERR(cc))
8440		return ERR_CAST(cc);
8441
8442	/* if vmlinux BTF has any candidate, don't go for module BTFs */
8443	if (cc->cnt)
8444		return cc;
8445
8446check_modules:
8447	/* cands is a pointer to stack here and cands->cnt == 0 */
8448	cc = check_cand_cache(cands, module_cand_cache, MODULE_CAND_CACHE_SIZE);
8449	if (cc)
8450		/* if cache has it return it even if cc->cnt == 0 */
8451		return cc;
8452
8453	/* If candidate is not found in vmlinux's BTF then search in module's BTFs */
8454	spin_lock_bh(&btf_idr_lock);
8455	idr_for_each_entry(&btf_idr, mod_btf, id) {
8456		if (!btf_is_module(mod_btf))
8457			continue;
8458		/* linear search could be slow hence unlock/lock
8459		 * the IDR to avoiding holding it for too long
8460		 */
8461		btf_get(mod_btf);
8462		spin_unlock_bh(&btf_idr_lock);
8463		cands = bpf_core_add_cands(cands, mod_btf, btf_nr_types(main_btf));
8464		btf_put(mod_btf);
8465		if (IS_ERR(cands))
8466			return ERR_CAST(cands);
8467		spin_lock_bh(&btf_idr_lock);
8468	}
8469	spin_unlock_bh(&btf_idr_lock);
8470	/* cands is a pointer to kmalloced memory here if cands->cnt > 0
8471	 * or pointer to stack if cands->cnd == 0.
8472	 * Copy it into the cache even when cands->cnt == 0 and
8473	 * return the result.
8474	 */
8475	return populate_cand_cache(cands, module_cand_cache, MODULE_CAND_CACHE_SIZE);
8476}
8477
8478int bpf_core_apply(struct bpf_core_ctx *ctx, const struct bpf_core_relo *relo,
8479		   int relo_idx, void *insn)
8480{
8481	bool need_cands = relo->kind != BPF_CORE_TYPE_ID_LOCAL;
8482	struct bpf_core_cand_list cands = {};
8483	struct bpf_core_relo_res targ_res;
8484	struct bpf_core_spec *specs;
8485	int err;
8486
8487	/* ~4k of temp memory necessary to convert LLVM spec like "0:1:0:5"
8488	 * into arrays of btf_ids of struct fields and array indices.
8489	 */
8490	specs = kcalloc(3, sizeof(*specs), GFP_KERNEL);
8491	if (!specs)
8492		return -ENOMEM;
8493
8494	if (need_cands) {
8495		struct bpf_cand_cache *cc;
8496		int i;
8497
8498		mutex_lock(&cand_cache_mutex);
8499		cc = bpf_core_find_cands(ctx, relo->type_id);
8500		if (IS_ERR(cc)) {
8501			bpf_log(ctx->log, "target candidate search failed for %d\n",
8502				relo->type_id);
8503			err = PTR_ERR(cc);
8504			goto out;
8505		}
8506		if (cc->cnt) {
8507			cands.cands = kcalloc(cc->cnt, sizeof(*cands.cands), GFP_KERNEL);
8508			if (!cands.cands) {
8509				err = -ENOMEM;
8510				goto out;
8511			}
8512		}
8513		for (i = 0; i < cc->cnt; i++) {
8514			bpf_log(ctx->log,
8515				"CO-RE relocating %s %s: found target candidate [%d]\n",
8516				btf_kind_str[cc->kind], cc->name, cc->cands[i].id);
8517			cands.cands[i].btf = cc->cands[i].btf;
8518			cands.cands[i].id = cc->cands[i].id;
8519		}
8520		cands.len = cc->cnt;
8521		/* cand_cache_mutex needs to span the cache lookup and
8522		 * copy of btf pointer into bpf_core_cand_list,
8523		 * since module can be unloaded while bpf_core_calc_relo_insn
8524		 * is working with module's btf.
8525		 */
8526	}
8527
8528	err = bpf_core_calc_relo_insn((void *)ctx->log, relo, relo_idx, ctx->btf, &cands, specs,
8529				      &targ_res);
8530	if (err)
8531		goto out;
8532
8533	err = bpf_core_patch_insn((void *)ctx->log, insn, relo->insn_off / 8, relo, relo_idx,
8534				  &targ_res);
8535
8536out:
8537	kfree(specs);
8538	if (need_cands) {
8539		kfree(cands.cands);
8540		mutex_unlock(&cand_cache_mutex);
8541		if (ctx->log->level & BPF_LOG_LEVEL2)
8542			print_cand_cache(ctx->log);
8543	}
8544	return err;
8545}
8546
8547bool btf_nested_type_is_trusted(struct bpf_verifier_log *log,
8548				const struct bpf_reg_state *reg,
8549				const char *field_name, u32 btf_id, const char *suffix)
8550{
8551	struct btf *btf = reg->btf;
8552	const struct btf_type *walk_type, *safe_type;
8553	const char *tname;
8554	char safe_tname[64];
8555	long ret, safe_id;
8556	const struct btf_member *member;
8557	u32 i;
8558
8559	walk_type = btf_type_by_id(btf, reg->btf_id);
8560	if (!walk_type)
8561		return false;
8562
8563	tname = btf_name_by_offset(btf, walk_type->name_off);
8564
8565	ret = snprintf(safe_tname, sizeof(safe_tname), "%s%s", tname, suffix);
8566	if (ret >= sizeof(safe_tname))
8567		return false;
8568
8569	safe_id = btf_find_by_name_kind(btf, safe_tname, BTF_INFO_KIND(walk_type->info));
8570	if (safe_id < 0)
8571		return false;
8572
8573	safe_type = btf_type_by_id(btf, safe_id);
8574	if (!safe_type)
8575		return false;
8576
8577	for_each_member(i, safe_type, member) {
8578		const char *m_name = __btf_name_by_offset(btf, member->name_off);
8579		const struct btf_type *mtype = btf_type_by_id(btf, member->type);
8580		u32 id;
8581
8582		if (!btf_type_is_ptr(mtype))
8583			continue;
8584
8585		btf_type_skip_modifiers(btf, mtype->type, &id);
8586		/* If we match on both type and name, the field is considered trusted. */
8587		if (btf_id == id && !strcmp(field_name, m_name))
8588			return true;
8589	}
8590
8591	return false;
8592}
8593
8594bool btf_type_ids_nocast_alias(struct bpf_verifier_log *log,
8595			       const struct btf *reg_btf, u32 reg_id,
8596			       const struct btf *arg_btf, u32 arg_id)
8597{
8598	const char *reg_name, *arg_name, *search_needle;
8599	const struct btf_type *reg_type, *arg_type;
8600	int reg_len, arg_len, cmp_len;
8601	size_t pattern_len = sizeof(NOCAST_ALIAS_SUFFIX) - sizeof(char);
8602
8603	reg_type = btf_type_by_id(reg_btf, reg_id);
8604	if (!reg_type)
8605		return false;
8606
8607	arg_type = btf_type_by_id(arg_btf, arg_id);
8608	if (!arg_type)
8609		return false;
8610
8611	reg_name = btf_name_by_offset(reg_btf, reg_type->name_off);
8612	arg_name = btf_name_by_offset(arg_btf, arg_type->name_off);
8613
8614	reg_len = strlen(reg_name);
8615	arg_len = strlen(arg_name);
8616
8617	/* Exactly one of the two type names may be suffixed with ___init, so
8618	 * if the strings are the same size, they can't possibly be no-cast
8619	 * aliases of one another. If you have two of the same type names, e.g.
8620	 * they're both nf_conn___init, it would be improper to return true
8621	 * because they are _not_ no-cast aliases, they are the same type.
8622	 */
8623	if (reg_len == arg_len)
8624		return false;
8625
8626	/* Either of the two names must be the other name, suffixed with ___init. */
8627	if ((reg_len != arg_len + pattern_len) &&
8628	    (arg_len != reg_len + pattern_len))
8629		return false;
8630
8631	if (reg_len < arg_len) {
8632		search_needle = strstr(arg_name, NOCAST_ALIAS_SUFFIX);
8633		cmp_len = reg_len;
8634	} else {
8635		search_needle = strstr(reg_name, NOCAST_ALIAS_SUFFIX);
8636		cmp_len = arg_len;
8637	}
8638
8639	if (!search_needle)
8640		return false;
8641
8642	/* ___init suffix must come at the end of the name */
8643	if (*(search_needle + pattern_len) != '\0')
8644		return false;
8645
8646	return !strncmp(reg_name, arg_name, cmp_len);
8647}