1// SPDX-License-Identifier: GPL-2.0-only
   2/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
   3 */
   4#include <linux/bpf.h>
   5#include <linux/btf.h>
   6#include <linux/bpf-cgroup.h>
   7#include <linux/cgroup.h>
   8#include <linux/rcupdate.h>
   9#include <linux/random.h>
  10#include <linux/smp.h>
  11#include <linux/topology.h>
  12#include <linux/ktime.h>
  13#include <linux/sched.h>
  14#include <linux/uidgid.h>
  15#include <linux/filter.h>
  16#include <linux/ctype.h>
  17#include <linux/jiffies.h>
  18#include <linux/pid_namespace.h>
  19#include <linux/poison.h>
  20#include <linux/proc_ns.h>
 
  21#include <linux/security.h>
  22#include <linux/btf_ids.h>
  23#include <linux/bpf_mem_alloc.h>
 
  24
  25#include "../../lib/kstrtox.h"
  26
  27/* If kernel subsystem is allowing eBPF programs to call this function,
  28 * inside its own verifier_ops->get_func_proto() callback it should return
  29 * bpf_map_lookup_elem_proto, so that verifier can properly check the arguments
  30 *
  31 * Different map implementations will rely on rcu in map methods
  32 * lookup/update/delete, therefore eBPF programs must run under rcu lock
  33 * if program is allowed to access maps, so check rcu_read_lock_held in
  34 * all three functions.
  35 */
  36BPF_CALL_2(bpf_map_lookup_elem, struct bpf_map *, map, void *, key)
  37{
  38	WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_bh_held());
 
  39	return (unsigned long) map->ops->map_lookup_elem(map, key);
  40}
  41
  42const struct bpf_func_proto bpf_map_lookup_elem_proto = {
  43	.func		= bpf_map_lookup_elem,
  44	.gpl_only	= false,
  45	.pkt_access	= true,
  46	.ret_type	= RET_PTR_TO_MAP_VALUE_OR_NULL,
  47	.arg1_type	= ARG_CONST_MAP_PTR,
  48	.arg2_type	= ARG_PTR_TO_MAP_KEY,
  49};
  50
  51BPF_CALL_4(bpf_map_update_elem, struct bpf_map *, map, void *, key,
  52	   void *, value, u64, flags)
  53{
  54	WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_bh_held());
 
  55	return map->ops->map_update_elem(map, key, value, flags);
  56}
  57
  58const struct bpf_func_proto bpf_map_update_elem_proto = {
  59	.func		= bpf_map_update_elem,
  60	.gpl_only	= false,
  61	.pkt_access	= true,
  62	.ret_type	= RET_INTEGER,
  63	.arg1_type	= ARG_CONST_MAP_PTR,
  64	.arg2_type	= ARG_PTR_TO_MAP_KEY,
  65	.arg3_type	= ARG_PTR_TO_MAP_VALUE,
  66	.arg4_type	= ARG_ANYTHING,
  67};
  68
  69BPF_CALL_2(bpf_map_delete_elem, struct bpf_map *, map, void *, key)
  70{
  71	WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_bh_held());
 
  72	return map->ops->map_delete_elem(map, key);
  73}
  74
  75const struct bpf_func_proto bpf_map_delete_elem_proto = {
  76	.func		= bpf_map_delete_elem,
  77	.gpl_only	= false,
  78	.pkt_access	= true,
  79	.ret_type	= RET_INTEGER,
  80	.arg1_type	= ARG_CONST_MAP_PTR,
  81	.arg2_type	= ARG_PTR_TO_MAP_KEY,
  82};
  83
  84BPF_CALL_3(bpf_map_push_elem, struct bpf_map *, map, void *, value, u64, flags)
  85{
  86	return map->ops->map_push_elem(map, value, flags);
  87}
  88
  89const struct bpf_func_proto bpf_map_push_elem_proto = {
  90	.func		= bpf_map_push_elem,
  91	.gpl_only	= false,
  92	.pkt_access	= true,
  93	.ret_type	= RET_INTEGER,
  94	.arg1_type	= ARG_CONST_MAP_PTR,
  95	.arg2_type	= ARG_PTR_TO_MAP_VALUE,
  96	.arg3_type	= ARG_ANYTHING,
  97};
  98
  99BPF_CALL_2(bpf_map_pop_elem, struct bpf_map *, map, void *, value)
 100{
 101	return map->ops->map_pop_elem(map, value);
 102}
 103
 104const struct bpf_func_proto bpf_map_pop_elem_proto = {
 105	.func		= bpf_map_pop_elem,
 106	.gpl_only	= false,
 107	.ret_type	= RET_INTEGER,
 108	.arg1_type	= ARG_CONST_MAP_PTR,
 109	.arg2_type	= ARG_PTR_TO_MAP_VALUE | MEM_UNINIT,
 110};
 111
 112BPF_CALL_2(bpf_map_peek_elem, struct bpf_map *, map, void *, value)
 113{
 114	return map->ops->map_peek_elem(map, value);
 115}
 116
 117const struct bpf_func_proto bpf_map_peek_elem_proto = {
 118	.func		= bpf_map_peek_elem,
 119	.gpl_only	= false,
 120	.ret_type	= RET_INTEGER,
 121	.arg1_type	= ARG_CONST_MAP_PTR,
 122	.arg2_type	= ARG_PTR_TO_MAP_VALUE | MEM_UNINIT,
 123};
 124
 125BPF_CALL_3(bpf_map_lookup_percpu_elem, struct bpf_map *, map, void *, key, u32, cpu)
 126{
 127	WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_bh_held());
 128	return (unsigned long) map->ops->map_lookup_percpu_elem(map, key, cpu);
 129}
 130
 131const struct bpf_func_proto bpf_map_lookup_percpu_elem_proto = {
 132	.func		= bpf_map_lookup_percpu_elem,
 133	.gpl_only	= false,
 134	.pkt_access	= true,
 135	.ret_type	= RET_PTR_TO_MAP_VALUE_OR_NULL,
 136	.arg1_type	= ARG_CONST_MAP_PTR,
 137	.arg2_type	= ARG_PTR_TO_MAP_KEY,
 138	.arg3_type	= ARG_ANYTHING,
 139};
 140
 141const struct bpf_func_proto bpf_get_prandom_u32_proto = {
 142	.func		= bpf_user_rnd_u32,
 143	.gpl_only	= false,
 144	.ret_type	= RET_INTEGER,
 145};
 146
 147BPF_CALL_0(bpf_get_smp_processor_id)
 148{
 149	return smp_processor_id();
 150}
 151
 152const struct bpf_func_proto bpf_get_smp_processor_id_proto = {
 153	.func		= bpf_get_smp_processor_id,
 154	.gpl_only	= false,
 155	.ret_type	= RET_INTEGER,
 156};
 157
 158BPF_CALL_0(bpf_get_numa_node_id)
 159{
 160	return numa_node_id();
 161}
 162
 163const struct bpf_func_proto bpf_get_numa_node_id_proto = {
 164	.func		= bpf_get_numa_node_id,
 165	.gpl_only	= false,
 166	.ret_type	= RET_INTEGER,
 167};
 168
 169BPF_CALL_0(bpf_ktime_get_ns)
 170{
 171	/* NMI safe access to clock monotonic */
 172	return ktime_get_mono_fast_ns();
 173}
 174
 175const struct bpf_func_proto bpf_ktime_get_ns_proto = {
 176	.func		= bpf_ktime_get_ns,
 177	.gpl_only	= false,
 178	.ret_type	= RET_INTEGER,
 179};
 180
 181BPF_CALL_0(bpf_ktime_get_boot_ns)
 182{
 183	/* NMI safe access to clock boottime */
 184	return ktime_get_boot_fast_ns();
 185}
 186
 187const struct bpf_func_proto bpf_ktime_get_boot_ns_proto = {
 188	.func		= bpf_ktime_get_boot_ns,
 189	.gpl_only	= false,
 190	.ret_type	= RET_INTEGER,
 191};
 192
 193BPF_CALL_0(bpf_ktime_get_coarse_ns)
 194{
 195	return ktime_get_coarse_ns();
 196}
 197
 198const struct bpf_func_proto bpf_ktime_get_coarse_ns_proto = {
 199	.func		= bpf_ktime_get_coarse_ns,
 200	.gpl_only	= false,
 201	.ret_type	= RET_INTEGER,
 202};
 203
 204BPF_CALL_0(bpf_ktime_get_tai_ns)
 205{
 206	/* NMI safe access to clock tai */
 207	return ktime_get_tai_fast_ns();
 208}
 209
 210const struct bpf_func_proto bpf_ktime_get_tai_ns_proto = {
 211	.func		= bpf_ktime_get_tai_ns,
 212	.gpl_only	= false,
 213	.ret_type	= RET_INTEGER,
 214};
 215
 216BPF_CALL_0(bpf_get_current_pid_tgid)
 217{
 218	struct task_struct *task = current;
 219
 220	if (unlikely(!task))
 221		return -EINVAL;
 222
 223	return (u64) task->tgid << 32 | task->pid;
 224}
 225
 226const struct bpf_func_proto bpf_get_current_pid_tgid_proto = {
 227	.func		= bpf_get_current_pid_tgid,
 228	.gpl_only	= false,
 229	.ret_type	= RET_INTEGER,
 230};
 231
 232BPF_CALL_0(bpf_get_current_uid_gid)
 233{
 234	struct task_struct *task = current;
 235	kuid_t uid;
 236	kgid_t gid;
 237
 238	if (unlikely(!task))
 239		return -EINVAL;
 240
 241	current_uid_gid(&uid, &gid);
 242	return (u64) from_kgid(&init_user_ns, gid) << 32 |
 243		     from_kuid(&init_user_ns, uid);
 244}
 245
 246const struct bpf_func_proto bpf_get_current_uid_gid_proto = {
 247	.func		= bpf_get_current_uid_gid,
 248	.gpl_only	= false,
 249	.ret_type	= RET_INTEGER,
 250};
 251
 252BPF_CALL_2(bpf_get_current_comm, char *, buf, u32, size)
 253{
 254	struct task_struct *task = current;
 255
 256	if (unlikely(!task))
 257		goto err_clear;
 258
 259	/* Verifier guarantees that size > 0 */
 260	strscpy(buf, task->comm, size);
 261	return 0;
 262err_clear:
 263	memset(buf, 0, size);
 264	return -EINVAL;
 265}
 266
 267const struct bpf_func_proto bpf_get_current_comm_proto = {
 268	.func		= bpf_get_current_comm,
 269	.gpl_only	= false,
 270	.ret_type	= RET_INTEGER,
 271	.arg1_type	= ARG_PTR_TO_UNINIT_MEM,
 272	.arg2_type	= ARG_CONST_SIZE,
 273};
 274
 275#if defined(CONFIG_QUEUED_SPINLOCKS) || defined(CONFIG_BPF_ARCH_SPINLOCK)
 276
 277static inline void __bpf_spin_lock(struct bpf_spin_lock *lock)
 278{
 279	arch_spinlock_t *l = (void *)lock;
 280	union {
 281		__u32 val;
 282		arch_spinlock_t lock;
 283	} u = { .lock = __ARCH_SPIN_LOCK_UNLOCKED };
 284
 285	compiletime_assert(u.val == 0, "__ARCH_SPIN_LOCK_UNLOCKED not 0");
 286	BUILD_BUG_ON(sizeof(*l) != sizeof(__u32));
 287	BUILD_BUG_ON(sizeof(*lock) != sizeof(__u32));
 
 288	arch_spin_lock(l);
 289}
 290
 291static inline void __bpf_spin_unlock(struct bpf_spin_lock *lock)
 292{
 293	arch_spinlock_t *l = (void *)lock;
 294
 295	arch_spin_unlock(l);
 
 296}
 297
 298#else
 299
 300static inline void __bpf_spin_lock(struct bpf_spin_lock *lock)
 301{
 302	atomic_t *l = (void *)lock;
 303
 304	BUILD_BUG_ON(sizeof(*l) != sizeof(*lock));
 305	do {
 306		atomic_cond_read_relaxed(l, !VAL);
 307	} while (atomic_xchg(l, 1));
 308}
 309
 310static inline void __bpf_spin_unlock(struct bpf_spin_lock *lock)
 311{
 312	atomic_t *l = (void *)lock;
 313
 314	atomic_set_release(l, 0);
 315}
 316
 317#endif
 318
 319static DEFINE_PER_CPU(unsigned long, irqsave_flags);
 320
 321static inline void __bpf_spin_lock_irqsave(struct bpf_spin_lock *lock)
 322{
 323	unsigned long flags;
 324
 325	local_irq_save(flags);
 326	__bpf_spin_lock(lock);
 327	__this_cpu_write(irqsave_flags, flags);
 328}
 329
 330notrace BPF_CALL_1(bpf_spin_lock, struct bpf_spin_lock *, lock)
 331{
 332	__bpf_spin_lock_irqsave(lock);
 333	return 0;
 334}
 335
 336const struct bpf_func_proto bpf_spin_lock_proto = {
 337	.func		= bpf_spin_lock,
 338	.gpl_only	= false,
 339	.ret_type	= RET_VOID,
 340	.arg1_type	= ARG_PTR_TO_SPIN_LOCK,
 341	.arg1_btf_id    = BPF_PTR_POISON,
 342};
 343
 344static inline void __bpf_spin_unlock_irqrestore(struct bpf_spin_lock *lock)
 345{
 346	unsigned long flags;
 347
 348	flags = __this_cpu_read(irqsave_flags);
 349	__bpf_spin_unlock(lock);
 350	local_irq_restore(flags);
 351}
 352
 353notrace BPF_CALL_1(bpf_spin_unlock, struct bpf_spin_lock *, lock)
 354{
 355	__bpf_spin_unlock_irqrestore(lock);
 356	return 0;
 357}
 358
 359const struct bpf_func_proto bpf_spin_unlock_proto = {
 360	.func		= bpf_spin_unlock,
 361	.gpl_only	= false,
 362	.ret_type	= RET_VOID,
 363	.arg1_type	= ARG_PTR_TO_SPIN_LOCK,
 364	.arg1_btf_id    = BPF_PTR_POISON,
 365};
 366
 367void copy_map_value_locked(struct bpf_map *map, void *dst, void *src,
 368			   bool lock_src)
 369{
 370	struct bpf_spin_lock *lock;
 371
 372	if (lock_src)
 373		lock = src + map->record->spin_lock_off;
 374	else
 375		lock = dst + map->record->spin_lock_off;
 376	preempt_disable();
 377	__bpf_spin_lock_irqsave(lock);
 378	copy_map_value(map, dst, src);
 379	__bpf_spin_unlock_irqrestore(lock);
 380	preempt_enable();
 381}
 382
 383BPF_CALL_0(bpf_jiffies64)
 384{
 385	return get_jiffies_64();
 386}
 387
 388const struct bpf_func_proto bpf_jiffies64_proto = {
 389	.func		= bpf_jiffies64,
 390	.gpl_only	= false,
 391	.ret_type	= RET_INTEGER,
 392};
 393
 394#ifdef CONFIG_CGROUPS
 395BPF_CALL_0(bpf_get_current_cgroup_id)
 396{
 397	struct cgroup *cgrp;
 398	u64 cgrp_id;
 399
 400	rcu_read_lock();
 401	cgrp = task_dfl_cgroup(current);
 402	cgrp_id = cgroup_id(cgrp);
 403	rcu_read_unlock();
 404
 405	return cgrp_id;
 406}
 407
 408const struct bpf_func_proto bpf_get_current_cgroup_id_proto = {
 409	.func		= bpf_get_current_cgroup_id,
 410	.gpl_only	= false,
 411	.ret_type	= RET_INTEGER,
 412};
 413
 414BPF_CALL_1(bpf_get_current_ancestor_cgroup_id, int, ancestor_level)
 415{
 416	struct cgroup *cgrp;
 417	struct cgroup *ancestor;
 418	u64 cgrp_id;
 419
 420	rcu_read_lock();
 421	cgrp = task_dfl_cgroup(current);
 422	ancestor = cgroup_ancestor(cgrp, ancestor_level);
 423	cgrp_id = ancestor ? cgroup_id(ancestor) : 0;
 424	rcu_read_unlock();
 425
 426	return cgrp_id;
 427}
 428
 429const struct bpf_func_proto bpf_get_current_ancestor_cgroup_id_proto = {
 430	.func		= bpf_get_current_ancestor_cgroup_id,
 431	.gpl_only	= false,
 432	.ret_type	= RET_INTEGER,
 433	.arg1_type	= ARG_ANYTHING,
 434};
 435#endif /* CONFIG_CGROUPS */
 436
 437#define BPF_STRTOX_BASE_MASK 0x1F
 438
 439static int __bpf_strtoull(const char *buf, size_t buf_len, u64 flags,
 440			  unsigned long long *res, bool *is_negative)
 441{
 442	unsigned int base = flags & BPF_STRTOX_BASE_MASK;
 443	const char *cur_buf = buf;
 444	size_t cur_len = buf_len;
 445	unsigned int consumed;
 446	size_t val_len;
 447	char str[64];
 448
 449	if (!buf || !buf_len || !res || !is_negative)
 450		return -EINVAL;
 451
 452	if (base != 0 && base != 8 && base != 10 && base != 16)
 453		return -EINVAL;
 454
 455	if (flags & ~BPF_STRTOX_BASE_MASK)
 456		return -EINVAL;
 457
 458	while (cur_buf < buf + buf_len && isspace(*cur_buf))
 459		++cur_buf;
 460
 461	*is_negative = (cur_buf < buf + buf_len && *cur_buf == '-');
 462	if (*is_negative)
 463		++cur_buf;
 464
 465	consumed = cur_buf - buf;
 466	cur_len -= consumed;
 467	if (!cur_len)
 468		return -EINVAL;
 469
 470	cur_len = min(cur_len, sizeof(str) - 1);
 471	memcpy(str, cur_buf, cur_len);
 472	str[cur_len] = '\0';
 473	cur_buf = str;
 474
 475	cur_buf = _parse_integer_fixup_radix(cur_buf, &base);
 476	val_len = _parse_integer(cur_buf, base, res);
 477
 478	if (val_len & KSTRTOX_OVERFLOW)
 479		return -ERANGE;
 480
 481	if (val_len == 0)
 482		return -EINVAL;
 483
 484	cur_buf += val_len;
 485	consumed += cur_buf - str;
 486
 487	return consumed;
 488}
 489
 490static int __bpf_strtoll(const char *buf, size_t buf_len, u64 flags,
 491			 long long *res)
 492{
 493	unsigned long long _res;
 494	bool is_negative;
 495	int err;
 496
 497	err = __bpf_strtoull(buf, buf_len, flags, &_res, &is_negative);
 498	if (err < 0)
 499		return err;
 500	if (is_negative) {
 501		if ((long long)-_res > 0)
 502			return -ERANGE;
 503		*res = -_res;
 504	} else {
 505		if ((long long)_res < 0)
 506			return -ERANGE;
 507		*res = _res;
 508	}
 509	return err;
 510}
 511
 512BPF_CALL_4(bpf_strtol, const char *, buf, size_t, buf_len, u64, flags,
 513	   long *, res)
 514{
 515	long long _res;
 516	int err;
 517
 518	err = __bpf_strtoll(buf, buf_len, flags, &_res);
 519	if (err < 0)
 520		return err;
 521	if (_res != (long)_res)
 522		return -ERANGE;
 523	*res = _res;
 524	return err;
 525}
 526
 527const struct bpf_func_proto bpf_strtol_proto = {
 528	.func		= bpf_strtol,
 529	.gpl_only	= false,
 530	.ret_type	= RET_INTEGER,
 531	.arg1_type	= ARG_PTR_TO_MEM | MEM_RDONLY,
 532	.arg2_type	= ARG_CONST_SIZE,
 533	.arg3_type	= ARG_ANYTHING,
 534	.arg4_type	= ARG_PTR_TO_LONG,
 535};
 536
 537BPF_CALL_4(bpf_strtoul, const char *, buf, size_t, buf_len, u64, flags,
 538	   unsigned long *, res)
 539{
 540	unsigned long long _res;
 541	bool is_negative;
 542	int err;
 543
 544	err = __bpf_strtoull(buf, buf_len, flags, &_res, &is_negative);
 545	if (err < 0)
 546		return err;
 547	if (is_negative)
 548		return -EINVAL;
 549	if (_res != (unsigned long)_res)
 550		return -ERANGE;
 551	*res = _res;
 552	return err;
 553}
 554
 555const struct bpf_func_proto bpf_strtoul_proto = {
 556	.func		= bpf_strtoul,
 557	.gpl_only	= false,
 558	.ret_type	= RET_INTEGER,
 559	.arg1_type	= ARG_PTR_TO_MEM | MEM_RDONLY,
 560	.arg2_type	= ARG_CONST_SIZE,
 561	.arg3_type	= ARG_ANYTHING,
 562	.arg4_type	= ARG_PTR_TO_LONG,
 563};
 564
 565BPF_CALL_3(bpf_strncmp, const char *, s1, u32, s1_sz, const char *, s2)
 566{
 567	return strncmp(s1, s2, s1_sz);
 568}
 569
 570static const struct bpf_func_proto bpf_strncmp_proto = {
 571	.func		= bpf_strncmp,
 572	.gpl_only	= false,
 573	.ret_type	= RET_INTEGER,
 574	.arg1_type	= ARG_PTR_TO_MEM,
 575	.arg2_type	= ARG_CONST_SIZE,
 576	.arg3_type	= ARG_PTR_TO_CONST_STR,
 577};
 578
 579BPF_CALL_4(bpf_get_ns_current_pid_tgid, u64, dev, u64, ino,
 580	   struct bpf_pidns_info *, nsdata, u32, size)
 581{
 582	struct task_struct *task = current;
 583	struct pid_namespace *pidns;
 584	int err = -EINVAL;
 585
 586	if (unlikely(size != sizeof(struct bpf_pidns_info)))
 587		goto clear;
 588
 589	if (unlikely((u64)(dev_t)dev != dev))
 590		goto clear;
 591
 592	if (unlikely(!task))
 593		goto clear;
 594
 595	pidns = task_active_pid_ns(task);
 596	if (unlikely(!pidns)) {
 597		err = -ENOENT;
 598		goto clear;
 599	}
 600
 601	if (!ns_match(&pidns->ns, (dev_t)dev, ino))
 602		goto clear;
 603
 604	nsdata->pid = task_pid_nr_ns(task, pidns);
 605	nsdata->tgid = task_tgid_nr_ns(task, pidns);
 606	return 0;
 607clear:
 608	memset((void *)nsdata, 0, (size_t) size);
 609	return err;
 610}
 611
 612const struct bpf_func_proto bpf_get_ns_current_pid_tgid_proto = {
 613	.func		= bpf_get_ns_current_pid_tgid,
 614	.gpl_only	= false,
 615	.ret_type	= RET_INTEGER,
 616	.arg1_type	= ARG_ANYTHING,
 617	.arg2_type	= ARG_ANYTHING,
 618	.arg3_type      = ARG_PTR_TO_UNINIT_MEM,
 619	.arg4_type      = ARG_CONST_SIZE,
 620};
 621
 622static const struct bpf_func_proto bpf_get_raw_smp_processor_id_proto = {
 623	.func		= bpf_get_raw_cpu_id,
 624	.gpl_only	= false,
 625	.ret_type	= RET_INTEGER,
 626};
 627
 628BPF_CALL_5(bpf_event_output_data, void *, ctx, struct bpf_map *, map,
 629	   u64, flags, void *, data, u64, size)
 630{
 631	if (unlikely(flags & ~(BPF_F_INDEX_MASK)))
 632		return -EINVAL;
 633
 634	return bpf_event_output(map, flags, data, size, NULL, 0, NULL);
 635}
 636
 637const struct bpf_func_proto bpf_event_output_data_proto =  {
 638	.func		= bpf_event_output_data,
 639	.gpl_only       = true,
 640	.ret_type       = RET_INTEGER,
 641	.arg1_type      = ARG_PTR_TO_CTX,
 642	.arg2_type      = ARG_CONST_MAP_PTR,
 643	.arg3_type      = ARG_ANYTHING,
 644	.arg4_type      = ARG_PTR_TO_MEM | MEM_RDONLY,
 645	.arg5_type      = ARG_CONST_SIZE_OR_ZERO,
 646};
 647
 648BPF_CALL_3(bpf_copy_from_user, void *, dst, u32, size,
 649	   const void __user *, user_ptr)
 650{
 651	int ret = copy_from_user(dst, user_ptr, size);
 652
 653	if (unlikely(ret)) {
 654		memset(dst, 0, size);
 655		ret = -EFAULT;
 656	}
 657
 658	return ret;
 659}
 660
 661const struct bpf_func_proto bpf_copy_from_user_proto = {
 662	.func		= bpf_copy_from_user,
 663	.gpl_only	= false,
 664	.might_sleep	= true,
 665	.ret_type	= RET_INTEGER,
 666	.arg1_type	= ARG_PTR_TO_UNINIT_MEM,
 667	.arg2_type	= ARG_CONST_SIZE_OR_ZERO,
 668	.arg3_type	= ARG_ANYTHING,
 669};
 670
 671BPF_CALL_5(bpf_copy_from_user_task, void *, dst, u32, size,
 672	   const void __user *, user_ptr, struct task_struct *, tsk, u64, flags)
 673{
 674	int ret;
 675
 676	/* flags is not used yet */
 677	if (unlikely(flags))
 678		return -EINVAL;
 679
 680	if (unlikely(!size))
 681		return 0;
 682
 683	ret = access_process_vm(tsk, (unsigned long)user_ptr, dst, size, 0);
 684	if (ret == size)
 685		return 0;
 686
 687	memset(dst, 0, size);
 688	/* Return -EFAULT for partial read */
 689	return ret < 0 ? ret : -EFAULT;
 690}
 691
 692const struct bpf_func_proto bpf_copy_from_user_task_proto = {
 693	.func		= bpf_copy_from_user_task,
 694	.gpl_only	= true,
 695	.might_sleep	= true,
 696	.ret_type	= RET_INTEGER,
 697	.arg1_type	= ARG_PTR_TO_UNINIT_MEM,
 698	.arg2_type	= ARG_CONST_SIZE_OR_ZERO,
 699	.arg3_type	= ARG_ANYTHING,
 700	.arg4_type	= ARG_PTR_TO_BTF_ID,
 701	.arg4_btf_id	= &btf_tracing_ids[BTF_TRACING_TYPE_TASK],
 702	.arg5_type	= ARG_ANYTHING
 703};
 704
 705BPF_CALL_2(bpf_per_cpu_ptr, const void *, ptr, u32, cpu)
 706{
 707	if (cpu >= nr_cpu_ids)
 708		return (unsigned long)NULL;
 709
 710	return (unsigned long)per_cpu_ptr((const void __percpu *)ptr, cpu);
 711}
 712
 713const struct bpf_func_proto bpf_per_cpu_ptr_proto = {
 714	.func		= bpf_per_cpu_ptr,
 715	.gpl_only	= false,
 716	.ret_type	= RET_PTR_TO_MEM_OR_BTF_ID | PTR_MAYBE_NULL | MEM_RDONLY,
 717	.arg1_type	= ARG_PTR_TO_PERCPU_BTF_ID,
 718	.arg2_type	= ARG_ANYTHING,
 719};
 720
 721BPF_CALL_1(bpf_this_cpu_ptr, const void *, percpu_ptr)
 722{
 723	return (unsigned long)this_cpu_ptr((const void __percpu *)percpu_ptr);
 724}
 725
 726const struct bpf_func_proto bpf_this_cpu_ptr_proto = {
 727	.func		= bpf_this_cpu_ptr,
 728	.gpl_only	= false,
 729	.ret_type	= RET_PTR_TO_MEM_OR_BTF_ID | MEM_RDONLY,
 730	.arg1_type	= ARG_PTR_TO_PERCPU_BTF_ID,
 731};
 732
 733static int bpf_trace_copy_string(char *buf, void *unsafe_ptr, char fmt_ptype,
 734		size_t bufsz)
 735{
 736	void __user *user_ptr = (__force void __user *)unsafe_ptr;
 737
 738	buf[0] = 0;
 739
 740	switch (fmt_ptype) {
 741	case 's':
 742#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
 743		if ((unsigned long)unsafe_ptr < TASK_SIZE)
 744			return strncpy_from_user_nofault(buf, user_ptr, bufsz);
 745		fallthrough;
 746#endif
 747	case 'k':
 748		return strncpy_from_kernel_nofault(buf, unsafe_ptr, bufsz);
 749	case 'u':
 750		return strncpy_from_user_nofault(buf, user_ptr, bufsz);
 751	}
 752
 753	return -EINVAL;
 754}
 755
 756/* Per-cpu temp buffers used by printf-like helpers to store the bprintf binary
 757 * arguments representation.
 758 */
 759#define MAX_BPRINTF_BUF_LEN	512
 760
 761/* Support executing three nested bprintf helper calls on a given CPU */
 762#define MAX_BPRINTF_NEST_LEVEL	3
 763struct bpf_bprintf_buffers {
 764	char tmp_bufs[MAX_BPRINTF_NEST_LEVEL][MAX_BPRINTF_BUF_LEN];
 
 765};
 766static DEFINE_PER_CPU(struct bpf_bprintf_buffers, bpf_bprintf_bufs);
 
 767static DEFINE_PER_CPU(int, bpf_bprintf_nest_level);
 768
 769static int try_get_fmt_tmp_buf(char **tmp_buf)
 770{
 771	struct bpf_bprintf_buffers *bufs;
 772	int nest_level;
 773
 774	preempt_disable();
 775	nest_level = this_cpu_inc_return(bpf_bprintf_nest_level);
 776	if (WARN_ON_ONCE(nest_level > MAX_BPRINTF_NEST_LEVEL)) {
 777		this_cpu_dec(bpf_bprintf_nest_level);
 778		preempt_enable();
 779		return -EBUSY;
 780	}
 781	bufs = this_cpu_ptr(&bpf_bprintf_bufs);
 782	*tmp_buf = bufs->tmp_bufs[nest_level - 1];
 783
 784	return 0;
 785}
 786
 787void bpf_bprintf_cleanup(void)
 788{
 789	if (this_cpu_read(bpf_bprintf_nest_level)) {
 790		this_cpu_dec(bpf_bprintf_nest_level);
 791		preempt_enable();
 792	}
 
 
 793}
 794
 795/*
 796 * bpf_bprintf_prepare - Generic pass on format strings for bprintf-like helpers
 797 *
 798 * Returns a negative value if fmt is an invalid format string or 0 otherwise.
 799 *
 800 * This can be used in two ways:
 801 * - Format string verification only: when bin_args is NULL
 802 * - Arguments preparation: in addition to the above verification, it writes in
 803 *   bin_args a binary representation of arguments usable by bstr_printf where
 804 *   pointers from BPF have been sanitized.
 805 *
 806 * In argument preparation mode, if 0 is returned, safe temporary buffers are
 807 * allocated and bpf_bprintf_cleanup should be called to free them after use.
 808 */
 809int bpf_bprintf_prepare(char *fmt, u32 fmt_size, const u64 *raw_args,
 810			u32 **bin_args, u32 num_args)
 811{
 
 812	char *unsafe_ptr = NULL, *tmp_buf = NULL, *tmp_buf_end, *fmt_end;
 
 813	size_t sizeof_cur_arg, sizeof_cur_ip;
 814	int err, i, num_spec = 0;
 815	u64 cur_arg;
 816	char fmt_ptype, cur_ip[16], ip_spec[] = "%pXX";
 817
 818	fmt_end = strnchr(fmt, fmt_size, 0);
 819	if (!fmt_end)
 820		return -EINVAL;
 821	fmt_size = fmt_end - fmt;
 822
 823	if (bin_args) {
 824		if (num_args && try_get_fmt_tmp_buf(&tmp_buf))
 825			return -EBUSY;
 826
 827		tmp_buf_end = tmp_buf + MAX_BPRINTF_BUF_LEN;
 828		*bin_args = (u32 *)tmp_buf;
 
 
 
 829	}
 830
 
 
 
 831	for (i = 0; i < fmt_size; i++) {
 832		if ((!isprint(fmt[i]) && !isspace(fmt[i])) || !isascii(fmt[i])) {
 833			err = -EINVAL;
 834			goto out;
 835		}
 836
 837		if (fmt[i] != '%')
 838			continue;
 839
 840		if (fmt[i + 1] == '%') {
 841			i++;
 842			continue;
 843		}
 844
 845		if (num_spec >= num_args) {
 846			err = -EINVAL;
 847			goto out;
 848		}
 849
 850		/* The string is zero-terminated so if fmt[i] != 0, we can
 851		 * always access fmt[i + 1], in the worst case it will be a 0
 852		 */
 853		i++;
 854
 855		/* skip optional "[0 +-][num]" width formatting field */
 856		while (fmt[i] == '0' || fmt[i] == '+'  || fmt[i] == '-' ||
 857		       fmt[i] == ' ')
 858			i++;
 859		if (fmt[i] >= '1' && fmt[i] <= '9') {
 860			i++;
 861			while (fmt[i] >= '0' && fmt[i] <= '9')
 862				i++;
 863		}
 864
 865		if (fmt[i] == 'p') {
 866			sizeof_cur_arg = sizeof(long);
 867
 868			if ((fmt[i + 1] == 'k' || fmt[i + 1] == 'u') &&
 869			    fmt[i + 2] == 's') {
 870				fmt_ptype = fmt[i + 1];
 871				i += 2;
 872				goto fmt_str;
 873			}
 874
 875			if (fmt[i + 1] == 0 || isspace(fmt[i + 1]) ||
 876			    ispunct(fmt[i + 1]) || fmt[i + 1] == 'K' ||
 877			    fmt[i + 1] == 'x' || fmt[i + 1] == 's' ||
 878			    fmt[i + 1] == 'S') {
 879				/* just kernel pointers */
 880				if (tmp_buf)
 881					cur_arg = raw_args[num_spec];
 882				i++;
 883				goto nocopy_fmt;
 884			}
 885
 886			if (fmt[i + 1] == 'B') {
 887				if (tmp_buf)  {
 888					err = snprintf(tmp_buf,
 889						       (tmp_buf_end - tmp_buf),
 890						       "%pB",
 891						       (void *)(long)raw_args[num_spec]);
 892					tmp_buf += (err + 1);
 893				}
 894
 895				i++;
 896				num_spec++;
 897				continue;
 898			}
 899
 900			/* only support "%pI4", "%pi4", "%pI6" and "%pi6". */
 901			if ((fmt[i + 1] != 'i' && fmt[i + 1] != 'I') ||
 902			    (fmt[i + 2] != '4' && fmt[i + 2] != '6')) {
 903				err = -EINVAL;
 904				goto out;
 905			}
 906
 907			i += 2;
 908			if (!tmp_buf)
 909				goto nocopy_fmt;
 910
 911			sizeof_cur_ip = (fmt[i] == '4') ? 4 : 16;
 912			if (tmp_buf_end - tmp_buf < sizeof_cur_ip) {
 913				err = -ENOSPC;
 914				goto out;
 915			}
 916
 917			unsafe_ptr = (char *)(long)raw_args[num_spec];
 918			err = copy_from_kernel_nofault(cur_ip, unsafe_ptr,
 919						       sizeof_cur_ip);
 920			if (err < 0)
 921				memset(cur_ip, 0, sizeof_cur_ip);
 922
 923			/* hack: bstr_printf expects IP addresses to be
 924			 * pre-formatted as strings, ironically, the easiest way
 925			 * to do that is to call snprintf.
 926			 */
 927			ip_spec[2] = fmt[i - 1];
 928			ip_spec[3] = fmt[i];
 929			err = snprintf(tmp_buf, tmp_buf_end - tmp_buf,
 930				       ip_spec, &cur_ip);
 931
 932			tmp_buf += err + 1;
 933			num_spec++;
 934
 935			continue;
 936		} else if (fmt[i] == 's') {
 937			fmt_ptype = fmt[i];
 938fmt_str:
 939			if (fmt[i + 1] != 0 &&
 940			    !isspace(fmt[i + 1]) &&
 941			    !ispunct(fmt[i + 1])) {
 942				err = -EINVAL;
 943				goto out;
 944			}
 945
 946			if (!tmp_buf)
 947				goto nocopy_fmt;
 948
 949			if (tmp_buf_end == tmp_buf) {
 950				err = -ENOSPC;
 951				goto out;
 952			}
 953
 954			unsafe_ptr = (char *)(long)raw_args[num_spec];
 955			err = bpf_trace_copy_string(tmp_buf, unsafe_ptr,
 956						    fmt_ptype,
 957						    tmp_buf_end - tmp_buf);
 958			if (err < 0) {
 959				tmp_buf[0] = '\0';
 960				err = 1;
 961			}
 962
 963			tmp_buf += err;
 964			num_spec++;
 965
 966			continue;
 967		} else if (fmt[i] == 'c') {
 968			if (!tmp_buf)
 969				goto nocopy_fmt;
 970
 971			if (tmp_buf_end == tmp_buf) {
 972				err = -ENOSPC;
 973				goto out;
 974			}
 975
 976			*tmp_buf = raw_args[num_spec];
 977			tmp_buf++;
 978			num_spec++;
 979
 980			continue;
 981		}
 982
 983		sizeof_cur_arg = sizeof(int);
 984
 985		if (fmt[i] == 'l') {
 986			sizeof_cur_arg = sizeof(long);
 987			i++;
 988		}
 989		if (fmt[i] == 'l') {
 990			sizeof_cur_arg = sizeof(long long);
 991			i++;
 992		}
 993
 994		if (fmt[i] != 'i' && fmt[i] != 'd' && fmt[i] != 'u' &&
 995		    fmt[i] != 'x' && fmt[i] != 'X') {
 996			err = -EINVAL;
 997			goto out;
 998		}
 999
1000		if (tmp_buf)
1001			cur_arg = raw_args[num_spec];
1002nocopy_fmt:
1003		if (tmp_buf) {
1004			tmp_buf = PTR_ALIGN(tmp_buf, sizeof(u32));
1005			if (tmp_buf_end - tmp_buf < sizeof_cur_arg) {
1006				err = -ENOSPC;
1007				goto out;
1008			}
1009
1010			if (sizeof_cur_arg == 8) {
1011				*(u32 *)tmp_buf = *(u32 *)&cur_arg;
1012				*(u32 *)(tmp_buf + 4) = *((u32 *)&cur_arg + 1);
1013			} else {
1014				*(u32 *)tmp_buf = (u32)(long)cur_arg;
1015			}
1016			tmp_buf += sizeof_cur_arg;
1017		}
1018		num_spec++;
1019	}
1020
1021	err = 0;
1022out:
1023	if (err)
1024		bpf_bprintf_cleanup();
1025	return err;
1026}
1027
1028BPF_CALL_5(bpf_snprintf, char *, str, u32, str_size, char *, fmt,
1029	   const void *, data, u32, data_len)
1030{
 
 
 
1031	int err, num_args;
1032	u32 *bin_args;
1033
1034	if (data_len % 8 || data_len > MAX_BPRINTF_VARARGS * 8 ||
1035	    (data_len && !data))
1036		return -EINVAL;
1037	num_args = data_len / 8;
1038
1039	/* ARG_PTR_TO_CONST_STR guarantees that fmt is zero-terminated so we
1040	 * can safely give an unbounded size.
1041	 */
1042	err = bpf_bprintf_prepare(fmt, UINT_MAX, data, &bin_args, num_args);
1043	if (err < 0)
1044		return err;
1045
1046	err = bstr_printf(str, str_size, fmt, bin_args);
1047
1048	bpf_bprintf_cleanup();
1049
1050	return err + 1;
1051}
1052
1053const struct bpf_func_proto bpf_snprintf_proto = {
1054	.func		= bpf_snprintf,
1055	.gpl_only	= true,
1056	.ret_type	= RET_INTEGER,
1057	.arg1_type	= ARG_PTR_TO_MEM_OR_NULL,
1058	.arg2_type	= ARG_CONST_SIZE_OR_ZERO,
1059	.arg3_type	= ARG_PTR_TO_CONST_STR,
1060	.arg4_type	= ARG_PTR_TO_MEM | PTR_MAYBE_NULL | MEM_RDONLY,
1061	.arg5_type	= ARG_CONST_SIZE_OR_ZERO,
1062};
1063
1064/* BPF map elements can contain 'struct bpf_timer'.
1065 * Such map owns all of its BPF timers.
1066 * 'struct bpf_timer' is allocated as part of map element allocation
1067 * and it's zero initialized.
1068 * That space is used to keep 'struct bpf_timer_kern'.
1069 * bpf_timer_init() allocates 'struct bpf_hrtimer', inits hrtimer, and
1070 * remembers 'struct bpf_map *' pointer it's part of.
1071 * bpf_timer_set_callback() increments prog refcnt and assign bpf callback_fn.
1072 * bpf_timer_start() arms the timer.
1073 * If user space reference to a map goes to zero at this point
1074 * ops->map_release_uref callback is responsible for cancelling the timers,
1075 * freeing their memory, and decrementing prog's refcnts.
1076 * bpf_timer_cancel() cancels the timer and decrements prog's refcnt.
1077 * Inner maps can contain bpf timers as well. ops->map_release_uref is
1078 * freeing the timers when inner map is replaced or deleted by user space.
1079 */
1080struct bpf_hrtimer {
1081	struct hrtimer timer;
1082	struct bpf_map *map;
1083	struct bpf_prog *prog;
1084	void __rcu *callback_fn;
1085	void *value;
 
1086};
1087
1088/* the actual struct hidden inside uapi struct bpf_timer */
1089struct bpf_timer_kern {
1090	struct bpf_hrtimer *timer;
1091	/* bpf_spin_lock is used here instead of spinlock_t to make
1092	 * sure that it always fits into space reserved by struct bpf_timer
1093	 * regardless of LOCKDEP and spinlock debug flags.
1094	 */
1095	struct bpf_spin_lock lock;
1096} __attribute__((aligned(8)));
1097
1098static DEFINE_PER_CPU(struct bpf_hrtimer *, hrtimer_running);
1099
1100static enum hrtimer_restart bpf_timer_cb(struct hrtimer *hrtimer)
1101{
1102	struct bpf_hrtimer *t = container_of(hrtimer, struct bpf_hrtimer, timer);
1103	struct bpf_map *map = t->map;
1104	void *value = t->value;
1105	bpf_callback_t callback_fn;
1106	void *key;
1107	u32 idx;
1108
1109	BTF_TYPE_EMIT(struct bpf_timer);
1110	callback_fn = rcu_dereference_check(t->callback_fn, rcu_read_lock_bh_held());
1111	if (!callback_fn)
1112		goto out;
1113
1114	/* bpf_timer_cb() runs in hrtimer_run_softirq. It doesn't migrate and
1115	 * cannot be preempted by another bpf_timer_cb() on the same cpu.
1116	 * Remember the timer this callback is servicing to prevent
1117	 * deadlock if callback_fn() calls bpf_timer_cancel() or
1118	 * bpf_map_delete_elem() on the same timer.
1119	 */
1120	this_cpu_write(hrtimer_running, t);
1121	if (map->map_type == BPF_MAP_TYPE_ARRAY) {
1122		struct bpf_array *array = container_of(map, struct bpf_array, map);
1123
1124		/* compute the key */
1125		idx = ((char *)value - array->value) / array->elem_size;
1126		key = &idx;
1127	} else { /* hash or lru */
1128		key = value - round_up(map->key_size, 8);
1129	}
1130
1131	callback_fn((u64)(long)map, (u64)(long)key, (u64)(long)value, 0, 0);
1132	/* The verifier checked that return value is zero. */
1133
1134	this_cpu_write(hrtimer_running, NULL);
1135out:
1136	return HRTIMER_NORESTART;
1137}
1138
1139BPF_CALL_3(bpf_timer_init, struct bpf_timer_kern *, timer, struct bpf_map *, map,
1140	   u64, flags)
1141{
1142	clockid_t clockid = flags & (MAX_CLOCKS - 1);
1143	struct bpf_hrtimer *t;
1144	int ret = 0;
1145
1146	BUILD_BUG_ON(MAX_CLOCKS != 16);
1147	BUILD_BUG_ON(sizeof(struct bpf_timer_kern) > sizeof(struct bpf_timer));
1148	BUILD_BUG_ON(__alignof__(struct bpf_timer_kern) != __alignof__(struct bpf_timer));
1149
1150	if (in_nmi())
1151		return -EOPNOTSUPP;
1152
1153	if (flags >= MAX_CLOCKS ||
1154	    /* similar to timerfd except _ALARM variants are not supported */
1155	    (clockid != CLOCK_MONOTONIC &&
1156	     clockid != CLOCK_REALTIME &&
1157	     clockid != CLOCK_BOOTTIME))
1158		return -EINVAL;
1159	__bpf_spin_lock_irqsave(&timer->lock);
1160	t = timer->timer;
1161	if (t) {
1162		ret = -EBUSY;
1163		goto out;
1164	}
1165	if (!atomic64_read(&map->usercnt)) {
1166		/* maps with timers must be either held by user space
1167		 * or pinned in bpffs.
1168		 */
1169		ret = -EPERM;
1170		goto out;
1171	}
1172	/* allocate hrtimer via map_kmalloc to use memcg accounting */
1173	t = bpf_map_kmalloc_node(map, sizeof(*t), GFP_ATOMIC, map->numa_node);
1174	if (!t) {
1175		ret = -ENOMEM;
1176		goto out;
1177	}
1178	t->value = (void *)timer - map->record->timer_off;
1179	t->map = map;
1180	t->prog = NULL;
1181	rcu_assign_pointer(t->callback_fn, NULL);
1182	hrtimer_init(&t->timer, clockid, HRTIMER_MODE_REL_SOFT);
1183	t->timer.function = bpf_timer_cb;
1184	timer->timer = t;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1185out:
1186	__bpf_spin_unlock_irqrestore(&timer->lock);
1187	return ret;
1188}
1189
1190static const struct bpf_func_proto bpf_timer_init_proto = {
1191	.func		= bpf_timer_init,
1192	.gpl_only	= true,
1193	.ret_type	= RET_INTEGER,
1194	.arg1_type	= ARG_PTR_TO_TIMER,
1195	.arg2_type	= ARG_CONST_MAP_PTR,
1196	.arg3_type	= ARG_ANYTHING,
1197};
1198
1199BPF_CALL_3(bpf_timer_set_callback, struct bpf_timer_kern *, timer, void *, callback_fn,
1200	   struct bpf_prog_aux *, aux)
1201{
1202	struct bpf_prog *prev, *prog = aux->prog;
1203	struct bpf_hrtimer *t;
1204	int ret = 0;
1205
1206	if (in_nmi())
1207		return -EOPNOTSUPP;
1208	__bpf_spin_lock_irqsave(&timer->lock);
1209	t = timer->timer;
1210	if (!t) {
1211		ret = -EINVAL;
1212		goto out;
1213	}
1214	if (!atomic64_read(&t->map->usercnt)) {
1215		/* maps with timers must be either held by user space
1216		 * or pinned in bpffs. Otherwise timer might still be
1217		 * running even when bpf prog is detached and user space
1218		 * is gone, since map_release_uref won't ever be called.
1219		 */
1220		ret = -EPERM;
1221		goto out;
1222	}
1223	prev = t->prog;
1224	if (prev != prog) {
1225		/* Bump prog refcnt once. Every bpf_timer_set_callback()
1226		 * can pick different callback_fn-s within the same prog.
1227		 */
1228		prog = bpf_prog_inc_not_zero(prog);
1229		if (IS_ERR(prog)) {
1230			ret = PTR_ERR(prog);
1231			goto out;
1232		}
1233		if (prev)
1234			/* Drop prev prog refcnt when swapping with new prog */
1235			bpf_prog_put(prev);
1236		t->prog = prog;
1237	}
1238	rcu_assign_pointer(t->callback_fn, callback_fn);
1239out:
1240	__bpf_spin_unlock_irqrestore(&timer->lock);
1241	return ret;
1242}
1243
1244static const struct bpf_func_proto bpf_timer_set_callback_proto = {
1245	.func		= bpf_timer_set_callback,
1246	.gpl_only	= true,
1247	.ret_type	= RET_INTEGER,
1248	.arg1_type	= ARG_PTR_TO_TIMER,
1249	.arg2_type	= ARG_PTR_TO_FUNC,
1250};
1251
1252BPF_CALL_3(bpf_timer_start, struct bpf_timer_kern *, timer, u64, nsecs, u64, flags)
1253{
1254	struct bpf_hrtimer *t;
1255	int ret = 0;
 
1256
1257	if (in_nmi())
1258		return -EOPNOTSUPP;
1259	if (flags)
1260		return -EINVAL;
1261	__bpf_spin_lock_irqsave(&timer->lock);
1262	t = timer->timer;
1263	if (!t || !t->prog) {
1264		ret = -EINVAL;
1265		goto out;
1266	}
1267	hrtimer_start(&t->timer, ns_to_ktime(nsecs), HRTIMER_MODE_REL_SOFT);
 
 
 
 
 
 
 
 
 
1268out:
1269	__bpf_spin_unlock_irqrestore(&timer->lock);
1270	return ret;
1271}
1272
1273static const struct bpf_func_proto bpf_timer_start_proto = {
1274	.func		= bpf_timer_start,
1275	.gpl_only	= true,
1276	.ret_type	= RET_INTEGER,
1277	.arg1_type	= ARG_PTR_TO_TIMER,
1278	.arg2_type	= ARG_ANYTHING,
1279	.arg3_type	= ARG_ANYTHING,
1280};
1281
1282static void drop_prog_refcnt(struct bpf_hrtimer *t)
1283{
1284	struct bpf_prog *prog = t->prog;
1285
1286	if (prog) {
1287		bpf_prog_put(prog);
1288		t->prog = NULL;
1289		rcu_assign_pointer(t->callback_fn, NULL);
1290	}
1291}
1292
1293BPF_CALL_1(bpf_timer_cancel, struct bpf_timer_kern *, timer)
1294{
1295	struct bpf_hrtimer *t;
1296	int ret = 0;
1297
1298	if (in_nmi())
1299		return -EOPNOTSUPP;
 
1300	__bpf_spin_lock_irqsave(&timer->lock);
1301	t = timer->timer;
1302	if (!t) {
1303		ret = -EINVAL;
1304		goto out;
1305	}
1306	if (this_cpu_read(hrtimer_running) == t) {
1307		/* If bpf callback_fn is trying to bpf_timer_cancel()
1308		 * its own timer the hrtimer_cancel() will deadlock
1309		 * since it waits for callback_fn to finish
1310		 */
1311		ret = -EDEADLK;
1312		goto out;
1313	}
1314	drop_prog_refcnt(t);
1315out:
1316	__bpf_spin_unlock_irqrestore(&timer->lock);
1317	/* Cancel the timer and wait for associated callback to finish
1318	 * if it was running.
1319	 */
1320	ret = ret ?: hrtimer_cancel(&t->timer);
 
1321	return ret;
1322}
1323
1324static const struct bpf_func_proto bpf_timer_cancel_proto = {
1325	.func		= bpf_timer_cancel,
1326	.gpl_only	= true,
1327	.ret_type	= RET_INTEGER,
1328	.arg1_type	= ARG_PTR_TO_TIMER,
1329};
1330
1331/* This function is called by map_delete/update_elem for individual element and
1332 * by ops->map_release_uref when the user space reference to a map reaches zero.
1333 */
1334void bpf_timer_cancel_and_free(void *val)
1335{
1336	struct bpf_timer_kern *timer = val;
1337	struct bpf_hrtimer *t;
1338
1339	/* Performance optimization: read timer->timer without lock first. */
1340	if (!READ_ONCE(timer->timer))
1341		return;
1342
1343	__bpf_spin_lock_irqsave(&timer->lock);
1344	/* re-read it under lock */
1345	t = timer->timer;
1346	if (!t)
1347		goto out;
1348	drop_prog_refcnt(t);
1349	/* The subsequent bpf_timer_start/cancel() helpers won't be able to use
1350	 * this timer, since it won't be initialized.
1351	 */
1352	timer->timer = NULL;
1353out:
1354	__bpf_spin_unlock_irqrestore(&timer->lock);
1355	if (!t)
1356		return;
1357	/* Cancel the timer and wait for callback to complete if it was running.
1358	 * If hrtimer_cancel() can be safely called it's safe to call kfree(t)
1359	 * right after for both preallocated and non-preallocated maps.
1360	 * The timer->timer = NULL was already done and no code path can
1361	 * see address 't' anymore.
1362	 *
1363	 * Check that bpf_map_delete/update_elem() wasn't called from timer
1364	 * callback_fn. In such case don't call hrtimer_cancel() (since it will
1365	 * deadlock) and don't call hrtimer_try_to_cancel() (since it will just
1366	 * return -1). Though callback_fn is still running on this cpu it's
1367	 * safe to do kfree(t) because bpf_timer_cb() read everything it needed
1368	 * from 't'. The bpf subprog callback_fn won't be able to access 't',
1369	 * since timer->timer = NULL was already done. The timer will be
1370	 * effectively cancelled because bpf_timer_cb() will return
1371	 * HRTIMER_NORESTART.
1372	 */
1373	if (this_cpu_read(hrtimer_running) != t)
1374		hrtimer_cancel(&t->timer);
1375	kfree(t);
1376}
1377
1378BPF_CALL_2(bpf_kptr_xchg, void *, map_value, void *, ptr)
1379{
1380	unsigned long *kptr = map_value;
1381
1382	return xchg(kptr, (unsigned long)ptr);
1383}
1384
1385/* Unlike other PTR_TO_BTF_ID helpers the btf_id in bpf_kptr_xchg()
1386 * helper is determined dynamically by the verifier. Use BPF_PTR_POISON to
1387 * denote type that verifier will determine.
1388 */
1389static const struct bpf_func_proto bpf_kptr_xchg_proto = {
1390	.func         = bpf_kptr_xchg,
1391	.gpl_only     = false,
1392	.ret_type     = RET_PTR_TO_BTF_ID_OR_NULL,
1393	.ret_btf_id   = BPF_PTR_POISON,
1394	.arg1_type    = ARG_PTR_TO_KPTR,
1395	.arg2_type    = ARG_PTR_TO_BTF_ID_OR_NULL | OBJ_RELEASE,
1396	.arg2_btf_id  = BPF_PTR_POISON,
1397};
1398
1399/* Since the upper 8 bits of dynptr->size is reserved, the
1400 * maximum supported size is 2^24 - 1.
1401 */
1402#define DYNPTR_MAX_SIZE	((1UL << 24) - 1)
1403#define DYNPTR_TYPE_SHIFT	28
1404#define DYNPTR_SIZE_MASK	0xFFFFFF
1405#define DYNPTR_RDONLY_BIT	BIT(31)
1406
1407static bool bpf_dynptr_is_rdonly(const struct bpf_dynptr_kern *ptr)
1408{
1409	return ptr->size & DYNPTR_RDONLY_BIT;
1410}
1411
 
 
 
 
 
1412static void bpf_dynptr_set_type(struct bpf_dynptr_kern *ptr, enum bpf_dynptr_type type)
1413{
1414	ptr->size |= type << DYNPTR_TYPE_SHIFT;
1415}
1416
1417u32 bpf_dynptr_get_size(const struct bpf_dynptr_kern *ptr)
 
 
 
 
 
1418{
1419	return ptr->size & DYNPTR_SIZE_MASK;
1420}
1421
 
 
 
 
 
 
 
1422int bpf_dynptr_check_size(u32 size)
1423{
1424	return size > DYNPTR_MAX_SIZE ? -E2BIG : 0;
1425}
1426
1427void bpf_dynptr_init(struct bpf_dynptr_kern *ptr, void *data,
1428		     enum bpf_dynptr_type type, u32 offset, u32 size)
1429{
1430	ptr->data = data;
1431	ptr->offset = offset;
1432	ptr->size = size;
1433	bpf_dynptr_set_type(ptr, type);
1434}
1435
1436void bpf_dynptr_set_null(struct bpf_dynptr_kern *ptr)
1437{
1438	memset(ptr, 0, sizeof(*ptr));
1439}
1440
1441static int bpf_dynptr_check_off_len(const struct bpf_dynptr_kern *ptr, u32 offset, u32 len)
1442{
1443	u32 size = bpf_dynptr_get_size(ptr);
1444
1445	if (len > size || offset > size - len)
1446		return -E2BIG;
1447
1448	return 0;
1449}
1450
1451BPF_CALL_4(bpf_dynptr_from_mem, void *, data, u32, size, u64, flags, struct bpf_dynptr_kern *, ptr)
1452{
1453	int err;
1454
1455	BTF_TYPE_EMIT(struct bpf_dynptr);
1456
1457	err = bpf_dynptr_check_size(size);
1458	if (err)
1459		goto error;
1460
1461	/* flags is currently unsupported */
1462	if (flags) {
1463		err = -EINVAL;
1464		goto error;
1465	}
1466
1467	bpf_dynptr_init(ptr, data, BPF_DYNPTR_TYPE_LOCAL, 0, size);
1468
1469	return 0;
1470
1471error:
1472	bpf_dynptr_set_null(ptr);
1473	return err;
1474}
1475
1476static const struct bpf_func_proto bpf_dynptr_from_mem_proto = {
1477	.func		= bpf_dynptr_from_mem,
1478	.gpl_only	= false,
1479	.ret_type	= RET_INTEGER,
1480	.arg1_type	= ARG_PTR_TO_UNINIT_MEM,
1481	.arg2_type	= ARG_CONST_SIZE_OR_ZERO,
1482	.arg3_type	= ARG_ANYTHING,
1483	.arg4_type	= ARG_PTR_TO_DYNPTR | DYNPTR_TYPE_LOCAL | MEM_UNINIT,
1484};
1485
1486BPF_CALL_5(bpf_dynptr_read, void *, dst, u32, len, const struct bpf_dynptr_kern *, src,
1487	   u32, offset, u64, flags)
1488{
 
1489	int err;
1490
1491	if (!src->data || flags)
1492		return -EINVAL;
1493
1494	err = bpf_dynptr_check_off_len(src, offset, len);
1495	if (err)
1496		return err;
1497
1498	/* Source and destination may possibly overlap, hence use memmove to
1499	 * copy the data. E.g. bpf_dynptr_from_mem may create two dynptr
1500	 * pointing to overlapping PTR_TO_MAP_VALUE regions.
1501	 */
1502	memmove(dst, src->data + src->offset + offset, len);
1503
1504	return 0;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1505}
1506
1507static const struct bpf_func_proto bpf_dynptr_read_proto = {
1508	.func		= bpf_dynptr_read,
1509	.gpl_only	= false,
1510	.ret_type	= RET_INTEGER,
1511	.arg1_type	= ARG_PTR_TO_UNINIT_MEM,
1512	.arg2_type	= ARG_CONST_SIZE_OR_ZERO,
1513	.arg3_type	= ARG_PTR_TO_DYNPTR | MEM_RDONLY,
1514	.arg4_type	= ARG_ANYTHING,
1515	.arg5_type	= ARG_ANYTHING,
1516};
1517
1518BPF_CALL_5(bpf_dynptr_write, const struct bpf_dynptr_kern *, dst, u32, offset, void *, src,
1519	   u32, len, u64, flags)
1520{
 
1521	int err;
1522
1523	if (!dst->data || flags || bpf_dynptr_is_rdonly(dst))
1524		return -EINVAL;
1525
1526	err = bpf_dynptr_check_off_len(dst, offset, len);
1527	if (err)
1528		return err;
1529
1530	/* Source and destination may possibly overlap, hence use memmove to
1531	 * copy the data. E.g. bpf_dynptr_from_mem may create two dynptr
1532	 * pointing to overlapping PTR_TO_MAP_VALUE regions.
1533	 */
1534	memmove(dst->data + dst->offset + offset, src, len);
1535
1536	return 0;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1537}
1538
1539static const struct bpf_func_proto bpf_dynptr_write_proto = {
1540	.func		= bpf_dynptr_write,
1541	.gpl_only	= false,
1542	.ret_type	= RET_INTEGER,
1543	.arg1_type	= ARG_PTR_TO_DYNPTR | MEM_RDONLY,
1544	.arg2_type	= ARG_ANYTHING,
1545	.arg3_type	= ARG_PTR_TO_MEM | MEM_RDONLY,
1546	.arg4_type	= ARG_CONST_SIZE_OR_ZERO,
1547	.arg5_type	= ARG_ANYTHING,
1548};
1549
1550BPF_CALL_3(bpf_dynptr_data, const struct bpf_dynptr_kern *, ptr, u32, offset, u32, len)
1551{
 
1552	int err;
1553
1554	if (!ptr->data)
1555		return 0;
1556
1557	err = bpf_dynptr_check_off_len(ptr, offset, len);
1558	if (err)
1559		return 0;
1560
1561	if (bpf_dynptr_is_rdonly(ptr))
1562		return 0;
1563
1564	return (unsigned long)(ptr->data + ptr->offset + offset);
 
 
 
 
 
 
 
 
 
 
 
 
 
1565}
1566
1567static const struct bpf_func_proto bpf_dynptr_data_proto = {
1568	.func		= bpf_dynptr_data,
1569	.gpl_only	= false,
1570	.ret_type	= RET_PTR_TO_DYNPTR_MEM_OR_NULL,
1571	.arg1_type	= ARG_PTR_TO_DYNPTR | MEM_RDONLY,
1572	.arg2_type	= ARG_ANYTHING,
1573	.arg3_type	= ARG_CONST_ALLOC_SIZE_OR_ZERO,
1574};
1575
1576const struct bpf_func_proto bpf_get_current_task_proto __weak;
1577const struct bpf_func_proto bpf_get_current_task_btf_proto __weak;
1578const struct bpf_func_proto bpf_probe_read_user_proto __weak;
1579const struct bpf_func_proto bpf_probe_read_user_str_proto __weak;
1580const struct bpf_func_proto bpf_probe_read_kernel_proto __weak;
1581const struct bpf_func_proto bpf_probe_read_kernel_str_proto __weak;
1582const struct bpf_func_proto bpf_task_pt_regs_proto __weak;
1583
1584const struct bpf_func_proto *
1585bpf_base_func_proto(enum bpf_func_id func_id)
1586{
1587	switch (func_id) {
1588	case BPF_FUNC_map_lookup_elem:
1589		return &bpf_map_lookup_elem_proto;
1590	case BPF_FUNC_map_update_elem:
1591		return &bpf_map_update_elem_proto;
1592	case BPF_FUNC_map_delete_elem:
1593		return &bpf_map_delete_elem_proto;
1594	case BPF_FUNC_map_push_elem:
1595		return &bpf_map_push_elem_proto;
1596	case BPF_FUNC_map_pop_elem:
1597		return &bpf_map_pop_elem_proto;
1598	case BPF_FUNC_map_peek_elem:
1599		return &bpf_map_peek_elem_proto;
1600	case BPF_FUNC_map_lookup_percpu_elem:
1601		return &bpf_map_lookup_percpu_elem_proto;
1602	case BPF_FUNC_get_prandom_u32:
1603		return &bpf_get_prandom_u32_proto;
1604	case BPF_FUNC_get_smp_processor_id:
1605		return &bpf_get_raw_smp_processor_id_proto;
1606	case BPF_FUNC_get_numa_node_id:
1607		return &bpf_get_numa_node_id_proto;
1608	case BPF_FUNC_tail_call:
1609		return &bpf_tail_call_proto;
1610	case BPF_FUNC_ktime_get_ns:
1611		return &bpf_ktime_get_ns_proto;
1612	case BPF_FUNC_ktime_get_boot_ns:
1613		return &bpf_ktime_get_boot_ns_proto;
1614	case BPF_FUNC_ktime_get_tai_ns:
1615		return &bpf_ktime_get_tai_ns_proto;
1616	case BPF_FUNC_ringbuf_output:
1617		return &bpf_ringbuf_output_proto;
1618	case BPF_FUNC_ringbuf_reserve:
1619		return &bpf_ringbuf_reserve_proto;
1620	case BPF_FUNC_ringbuf_submit:
1621		return &bpf_ringbuf_submit_proto;
1622	case BPF_FUNC_ringbuf_discard:
1623		return &bpf_ringbuf_discard_proto;
1624	case BPF_FUNC_ringbuf_query:
1625		return &bpf_ringbuf_query_proto;
1626	case BPF_FUNC_strncmp:
1627		return &bpf_strncmp_proto;
1628	case BPF_FUNC_strtol:
1629		return &bpf_strtol_proto;
1630	case BPF_FUNC_strtoul:
1631		return &bpf_strtoul_proto;
1632	default:
1633		break;
1634	}
1635
1636	if (!bpf_capable())
1637		return NULL;
1638
1639	switch (func_id) {
1640	case BPF_FUNC_spin_lock:
1641		return &bpf_spin_lock_proto;
1642	case BPF_FUNC_spin_unlock:
1643		return &bpf_spin_unlock_proto;
1644	case BPF_FUNC_jiffies64:
1645		return &bpf_jiffies64_proto;
1646	case BPF_FUNC_per_cpu_ptr:
1647		return &bpf_per_cpu_ptr_proto;
1648	case BPF_FUNC_this_cpu_ptr:
1649		return &bpf_this_cpu_ptr_proto;
1650	case BPF_FUNC_timer_init:
1651		return &bpf_timer_init_proto;
1652	case BPF_FUNC_timer_set_callback:
1653		return &bpf_timer_set_callback_proto;
1654	case BPF_FUNC_timer_start:
1655		return &bpf_timer_start_proto;
1656	case BPF_FUNC_timer_cancel:
1657		return &bpf_timer_cancel_proto;
1658	case BPF_FUNC_kptr_xchg:
1659		return &bpf_kptr_xchg_proto;
1660	case BPF_FUNC_for_each_map_elem:
1661		return &bpf_for_each_map_elem_proto;
1662	case BPF_FUNC_loop:
1663		return &bpf_loop_proto;
1664	case BPF_FUNC_user_ringbuf_drain:
1665		return &bpf_user_ringbuf_drain_proto;
1666	case BPF_FUNC_ringbuf_reserve_dynptr:
1667		return &bpf_ringbuf_reserve_dynptr_proto;
1668	case BPF_FUNC_ringbuf_submit_dynptr:
1669		return &bpf_ringbuf_submit_dynptr_proto;
1670	case BPF_FUNC_ringbuf_discard_dynptr:
1671		return &bpf_ringbuf_discard_dynptr_proto;
1672	case BPF_FUNC_dynptr_from_mem:
1673		return &bpf_dynptr_from_mem_proto;
1674	case BPF_FUNC_dynptr_read:
1675		return &bpf_dynptr_read_proto;
1676	case BPF_FUNC_dynptr_write:
1677		return &bpf_dynptr_write_proto;
1678	case BPF_FUNC_dynptr_data:
1679		return &bpf_dynptr_data_proto;
1680#ifdef CONFIG_CGROUPS
1681	case BPF_FUNC_cgrp_storage_get:
1682		return &bpf_cgrp_storage_get_proto;
1683	case BPF_FUNC_cgrp_storage_delete:
1684		return &bpf_cgrp_storage_delete_proto;
 
 
 
 
1685#endif
1686	default:
1687		break;
1688	}
1689
1690	if (!perfmon_capable())
1691		return NULL;
1692
1693	switch (func_id) {
1694	case BPF_FUNC_trace_printk:
1695		return bpf_get_trace_printk_proto();
1696	case BPF_FUNC_get_current_task:
1697		return &bpf_get_current_task_proto;
1698	case BPF_FUNC_get_current_task_btf:
1699		return &bpf_get_current_task_btf_proto;
1700	case BPF_FUNC_probe_read_user:
1701		return &bpf_probe_read_user_proto;
1702	case BPF_FUNC_probe_read_kernel:
1703		return security_locked_down(LOCKDOWN_BPF_READ_KERNEL) < 0 ?
1704		       NULL : &bpf_probe_read_kernel_proto;
1705	case BPF_FUNC_probe_read_user_str:
1706		return &bpf_probe_read_user_str_proto;
1707	case BPF_FUNC_probe_read_kernel_str:
1708		return security_locked_down(LOCKDOWN_BPF_READ_KERNEL) < 0 ?
1709		       NULL : &bpf_probe_read_kernel_str_proto;
1710	case BPF_FUNC_snprintf_btf:
1711		return &bpf_snprintf_btf_proto;
1712	case BPF_FUNC_snprintf:
1713		return &bpf_snprintf_proto;
1714	case BPF_FUNC_task_pt_regs:
1715		return &bpf_task_pt_regs_proto;
1716	case BPF_FUNC_trace_vprintk:
1717		return bpf_get_trace_vprintk_proto();
1718	default:
1719		return NULL;
1720	}
1721}
1722
1723void bpf_list_head_free(const struct btf_field *field, void *list_head,
1724			struct bpf_spin_lock *spin_lock)
1725{
1726	struct list_head *head = list_head, *orig_head = list_head;
1727
1728	BUILD_BUG_ON(sizeof(struct list_head) > sizeof(struct bpf_list_head));
1729	BUILD_BUG_ON(__alignof__(struct list_head) > __alignof__(struct bpf_list_head));
1730
1731	/* Do the actual list draining outside the lock to not hold the lock for
1732	 * too long, and also prevent deadlocks if tracing programs end up
1733	 * executing on entry/exit of functions called inside the critical
1734	 * section, and end up doing map ops that call bpf_list_head_free for
1735	 * the same map value again.
1736	 */
1737	__bpf_spin_lock_irqsave(spin_lock);
1738	if (!head->next || list_empty(head))
1739		goto unlock;
1740	head = head->next;
1741unlock:
1742	INIT_LIST_HEAD(orig_head);
1743	__bpf_spin_unlock_irqrestore(spin_lock);
1744
1745	while (head != orig_head) {
1746		void *obj = head;
1747
1748		obj -= field->list_head.node_offset;
1749		head = head->next;
1750		/* The contained type can also have resources, including a
1751		 * bpf_list_head which needs to be freed.
1752		 */
1753		bpf_obj_free_fields(field->list_head.value_rec, obj);
1754		/* bpf_mem_free requires migrate_disable(), since we can be
1755		 * called from map free path as well apart from BPF program (as
1756		 * part of map ops doing bpf_obj_free_fields).
1757		 */
1758		migrate_disable();
1759		bpf_mem_free(&bpf_global_ma, obj);
1760		migrate_enable();
1761	}
1762}
1763
1764__diag_push();
1765__diag_ignore_all("-Wmissing-prototypes",
1766		  "Global functions as their definitions will be in vmlinux BTF");
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1767
1768void *bpf_obj_new_impl(u64 local_type_id__k, void *meta__ign)
 
 
 
 
 
 
 
 
 
 
 
 
 
1769{
1770	struct btf_struct_meta *meta = meta__ign;
1771	u64 size = local_type_id__k;
1772	void *p;
1773
1774	p = bpf_mem_alloc(&bpf_global_ma, size);
1775	if (!p)
1776		return NULL;
1777	if (meta)
1778		bpf_obj_init(meta->field_offs, p);
1779	return p;
1780}
1781
1782void bpf_obj_drop_impl(void *p__alloc, void *meta__ign)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1783{
1784	struct btf_struct_meta *meta = meta__ign;
1785	void *p = p__alloc;
1786
1787	if (meta)
1788		bpf_obj_free_fields(meta->record, p);
1789	bpf_mem_free(&bpf_global_ma, p);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1790}
1791
1792static void __bpf_list_add(struct bpf_list_node *node, struct bpf_list_head *head, bool tail)
 
 
1793{
1794	struct list_head *n = (void *)node, *h = (void *)head;
1795
 
 
 
1796	if (unlikely(!h->next))
1797		INIT_LIST_HEAD(h);
1798	if (unlikely(!n->next))
1799		INIT_LIST_HEAD(n);
 
 
 
 
 
 
 
 
1800	tail ? list_add_tail(n, h) : list_add(n, h);
 
 
 
1801}
1802
1803void bpf_list_push_front(struct bpf_list_head *head, struct bpf_list_node *node)
 
 
1804{
1805	return __bpf_list_add(node, head, false);
 
 
 
1806}
1807
1808void bpf_list_push_back(struct bpf_list_head *head, struct bpf_list_node *node)
 
 
1809{
1810	return __bpf_list_add(node, head, true);
 
 
 
1811}
1812
1813static struct bpf_list_node *__bpf_list_del(struct bpf_list_head *head, bool tail)
1814{
1815	struct list_head *n, *h = (void *)head;
 
1816
 
 
 
1817	if (unlikely(!h->next))
1818		INIT_LIST_HEAD(h);
1819	if (list_empty(h))
1820		return NULL;
 
1821	n = tail ? h->prev : h->next;
 
 
 
 
1822	list_del_init(n);
 
1823	return (struct bpf_list_node *)n;
1824}
1825
1826struct bpf_list_node *bpf_list_pop_front(struct bpf_list_head *head)
1827{
1828	return __bpf_list_del(head, false);
1829}
1830
1831struct bpf_list_node *bpf_list_pop_back(struct bpf_list_head *head)
1832{
1833	return __bpf_list_del(head, true);
1834}
1835
1836/**
1837 * bpf_task_acquire - Acquire a reference to a task. A task acquired by this
1838 * kfunc which is not stored in a map as a kptr, must be released by calling
1839 * bpf_task_release().
1840 * @p: The task on which a reference is being acquired.
1841 */
1842struct task_struct *bpf_task_acquire(struct task_struct *p)
1843{
1844	return get_task_struct(p);
 
 
 
 
 
 
 
 
 
 
 
 
 
1845}
1846
1847/**
1848 * bpf_task_acquire_not_zero - Acquire a reference to a rcu task object. A task
1849 * acquired by this kfunc which is not stored in a map as a kptr, must be
1850 * released by calling bpf_task_release().
1851 * @p: The task on which a reference is being acquired.
1852 */
1853struct task_struct *bpf_task_acquire_not_zero(struct task_struct *p)
1854{
1855	/* For the time being this function returns NULL, as it's not currently
1856	 * possible to safely acquire a reference to a task with RCU protection
1857	 * using get_task_struct() and put_task_struct(). This is due to the
1858	 * slightly odd mechanics of p->rcu_users, and how task RCU protection
1859	 * works.
1860	 *
1861	 * A struct task_struct is refcounted by two different refcount_t
1862	 * fields:
1863	 *
1864	 * 1. p->usage:     The "true" refcount field which tracks a task's
1865	 *		    lifetime. The task is freed as soon as this
1866	 *		    refcount drops to 0.
1867	 *
1868	 * 2. p->rcu_users: An "RCU users" refcount field which is statically
1869	 *		    initialized to 2, and is co-located in a union with
1870	 *		    a struct rcu_head field (p->rcu). p->rcu_users
1871	 *		    essentially encapsulates a single p->usage
1872	 *		    refcount, and when p->rcu_users goes to 0, an RCU
1873	 *		    callback is scheduled on the struct rcu_head which
1874	 *		    decrements the p->usage refcount.
1875	 *
1876	 * There are two important implications to this task refcounting logic
1877	 * described above. The first is that
1878	 * refcount_inc_not_zero(&p->rcu_users) cannot be used anywhere, as
1879	 * after the refcount goes to 0, the RCU callback being scheduled will
1880	 * cause the memory backing the refcount to again be nonzero due to the
1881	 * fields sharing a union. The other is that we can't rely on RCU to
1882	 * guarantee that a task is valid in a BPF program. This is because a
1883	 * task could have already transitioned to being in the TASK_DEAD
1884	 * state, had its rcu_users refcount go to 0, and its rcu callback
1885	 * invoked in which it drops its single p->usage reference. At this
1886	 * point the task will be freed as soon as the last p->usage reference
1887	 * goes to 0, without waiting for another RCU gp to elapse. The only
1888	 * way that a BPF program can guarantee that a task is valid is in this
1889	 * scenario is to hold a p->usage refcount itself.
1890	 *
1891	 * Until we're able to resolve this issue, either by pulling
1892	 * p->rcu_users and p->rcu out of the union, or by getting rid of
1893	 * p->usage and just using p->rcu_users for refcounting, we'll just
1894	 * return NULL here.
1895	 */
1896	return NULL;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1897}
1898
1899/**
1900 * bpf_task_kptr_get - Acquire a reference on a struct task_struct kptr. A task
1901 * kptr acquired by this kfunc which is not subsequently stored in a map, must
1902 * be released by calling bpf_task_release().
1903 * @pp: A pointer to a task kptr on which a reference is being acquired.
1904 */
1905struct task_struct *bpf_task_kptr_get(struct task_struct **pp)
1906{
1907	/* We must return NULL here until we have clarity on how to properly
1908	 * leverage RCU for ensuring a task's lifetime. See the comment above
1909	 * in bpf_task_acquire_not_zero() for more details.
1910	 */
1911	return NULL;
1912}
1913
1914/**
1915 * bpf_task_release - Release the reference acquired on a task.
1916 * @p: The task on which a reference is being released.
1917 */
1918void bpf_task_release(struct task_struct *p)
1919{
1920	if (!p)
1921		return;
1922
1923	put_task_struct(p);
 
 
1924}
 
1925
1926#ifdef CONFIG_CGROUPS
1927/**
1928 * bpf_cgroup_acquire - Acquire a reference to a cgroup. A cgroup acquired by
1929 * this kfunc which is not stored in a map as a kptr, must be released by
1930 * calling bpf_cgroup_release().
1931 * @cgrp: The cgroup on which a reference is being acquired.
1932 */
1933struct cgroup *bpf_cgroup_acquire(struct cgroup *cgrp)
1934{
1935	cgroup_get(cgrp);
1936	return cgrp;
1937}
1938
1939/**
1940 * bpf_cgroup_kptr_get - Acquire a reference on a struct cgroup kptr. A cgroup
1941 * kptr acquired by this kfunc which is not subsequently stored in a map, must
1942 * be released by calling bpf_cgroup_release().
1943 * @cgrpp: A pointer to a cgroup kptr on which a reference is being acquired.
1944 */
1945struct cgroup *bpf_cgroup_kptr_get(struct cgroup **cgrpp)
1946{
1947	struct cgroup *cgrp;
1948
1949	rcu_read_lock();
1950	/* Another context could remove the cgroup from the map and release it
1951	 * at any time, including after we've done the lookup above. This is
1952	 * safe because we're in an RCU read region, so the cgroup is
1953	 * guaranteed to remain valid until at least the rcu_read_unlock()
1954	 * below.
1955	 */
1956	cgrp = READ_ONCE(*cgrpp);
1957
1958	if (cgrp && !cgroup_tryget(cgrp))
1959		/* If the cgroup had been removed from the map and freed as
1960		 * described above, cgroup_tryget() will return false. The
1961		 * cgroup will be freed at some point after the current RCU gp
1962		 * has ended, so just return NULL to the user.
1963		 */
1964		cgrp = NULL;
1965	rcu_read_unlock();
1966
1967	return cgrp;
1968}
1969
1970/**
1971 * bpf_cgroup_release - Release the reference acquired on a cgroup.
1972 * If this kfunc is invoked in an RCU read region, the cgroup is guaranteed to
1973 * not be freed until the current grace period has ended, even if its refcount
1974 * drops to 0.
1975 * @cgrp: The cgroup on which a reference is being released.
1976 */
1977void bpf_cgroup_release(struct cgroup *cgrp)
1978{
1979	if (!cgrp)
1980		return;
1981
 
 
1982	cgroup_put(cgrp);
1983}
 
1984
1985/**
1986 * bpf_cgroup_ancestor - Perform a lookup on an entry in a cgroup's ancestor
1987 * array. A cgroup returned by this kfunc which is not subsequently stored in a
1988 * map, must be released by calling bpf_cgroup_release().
1989 * @cgrp: The cgroup for which we're performing a lookup.
1990 * @level: The level of ancestor to look up.
1991 */
1992struct cgroup *bpf_cgroup_ancestor(struct cgroup *cgrp, int level)
1993{
1994	struct cgroup *ancestor;
1995
1996	if (level > cgrp->level || level < 0)
1997		return NULL;
1998
 
1999	ancestor = cgrp->ancestors[level];
2000	cgroup_get(ancestor);
 
2001	return ancestor;
2002}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2003#endif /* CONFIG_CGROUPS */
2004
2005/**
2006 * bpf_task_from_pid - Find a struct task_struct from its pid by looking it up
2007 * in the root pid namespace idr. If a task is returned, it must either be
2008 * stored in a map, or released with bpf_task_release().
2009 * @pid: The pid of the task being looked up.
2010 */
2011struct task_struct *bpf_task_from_pid(s32 pid)
2012{
2013	struct task_struct *p;
2014
2015	rcu_read_lock();
2016	p = find_task_by_pid_ns(pid, &init_pid_ns);
2017	if (p)
2018		bpf_task_acquire(p);
2019	rcu_read_unlock();
2020
2021	return p;
2022}
2023
2024void *bpf_cast_to_kern_ctx(void *obj)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2025{
2026	return obj;
2027}
2028
2029void *bpf_rdonly_cast(void *obj__ign, u32 btf_id__k)
2030{
2031	return obj__ign;
2032}
2033
2034void bpf_rcu_read_lock(void)
2035{
2036	rcu_read_lock();
2037}
2038
2039void bpf_rcu_read_unlock(void)
2040{
2041	rcu_read_unlock();
2042}
2043
2044__diag_pop();
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2045
2046BTF_SET8_START(generic_btf_ids)
2047#ifdef CONFIG_KEXEC_CORE
2048BTF_ID_FLAGS(func, crash_kexec, KF_DESTRUCTIVE)
2049#endif
2050BTF_ID_FLAGS(func, bpf_obj_new_impl, KF_ACQUIRE | KF_RET_NULL)
 
2051BTF_ID_FLAGS(func, bpf_obj_drop_impl, KF_RELEASE)
2052BTF_ID_FLAGS(func, bpf_list_push_front)
2053BTF_ID_FLAGS(func, bpf_list_push_back)
 
 
2054BTF_ID_FLAGS(func, bpf_list_pop_front, KF_ACQUIRE | KF_RET_NULL)
2055BTF_ID_FLAGS(func, bpf_list_pop_back, KF_ACQUIRE | KF_RET_NULL)
2056BTF_ID_FLAGS(func, bpf_task_acquire, KF_ACQUIRE | KF_TRUSTED_ARGS)
2057BTF_ID_FLAGS(func, bpf_task_acquire_not_zero, KF_ACQUIRE | KF_RCU | KF_RET_NULL)
2058BTF_ID_FLAGS(func, bpf_task_kptr_get, KF_ACQUIRE | KF_KPTR_GET | KF_RET_NULL)
2059BTF_ID_FLAGS(func, bpf_task_release, KF_RELEASE)
 
 
 
 
2060#ifdef CONFIG_CGROUPS
2061BTF_ID_FLAGS(func, bpf_cgroup_acquire, KF_ACQUIRE | KF_TRUSTED_ARGS)
2062BTF_ID_FLAGS(func, bpf_cgroup_kptr_get, KF_ACQUIRE | KF_KPTR_GET | KF_RET_NULL)
2063BTF_ID_FLAGS(func, bpf_cgroup_release, KF_RELEASE)
2064BTF_ID_FLAGS(func, bpf_cgroup_ancestor, KF_ACQUIRE | KF_TRUSTED_ARGS | KF_RET_NULL)
 
 
 
2065#endif
2066BTF_ID_FLAGS(func, bpf_task_from_pid, KF_ACQUIRE | KF_RET_NULL)
 
2067BTF_SET8_END(generic_btf_ids)
2068
2069static const struct btf_kfunc_id_set generic_kfunc_set = {
2070	.owner = THIS_MODULE,
2071	.set   = &generic_btf_ids,
2072};
2073
2074
2075BTF_ID_LIST(generic_dtor_ids)
2076BTF_ID(struct, task_struct)
2077BTF_ID(func, bpf_task_release)
2078#ifdef CONFIG_CGROUPS
2079BTF_ID(struct, cgroup)
2080BTF_ID(func, bpf_cgroup_release)
2081#endif
2082
2083BTF_SET8_START(common_btf_ids)
2084BTF_ID_FLAGS(func, bpf_cast_to_kern_ctx)
2085BTF_ID_FLAGS(func, bpf_rdonly_cast)
2086BTF_ID_FLAGS(func, bpf_rcu_read_lock)
2087BTF_ID_FLAGS(func, bpf_rcu_read_unlock)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2088BTF_SET8_END(common_btf_ids)
2089
2090static const struct btf_kfunc_id_set common_kfunc_set = {
2091	.owner = THIS_MODULE,
2092	.set   = &common_btf_ids,
2093};
2094
2095static int __init kfunc_init(void)
2096{
2097	int ret;
2098	const struct btf_id_dtor_kfunc generic_dtors[] = {
2099		{
2100			.btf_id       = generic_dtor_ids[0],
2101			.kfunc_btf_id = generic_dtor_ids[1]
2102		},
2103#ifdef CONFIG_CGROUPS
2104		{
2105			.btf_id       = generic_dtor_ids[2],
2106			.kfunc_btf_id = generic_dtor_ids[3]
2107		},
2108#endif
2109	};
2110
2111	ret = register_btf_kfunc_id_set(BPF_PROG_TYPE_TRACING, &generic_kfunc_set);
2112	ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_SCHED_CLS, &generic_kfunc_set);
 
2113	ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_STRUCT_OPS, &generic_kfunc_set);
2114	ret = ret ?: register_btf_id_dtor_kfuncs(generic_dtors,
2115						  ARRAY_SIZE(generic_dtors),
2116						  THIS_MODULE);
2117	return ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_UNSPEC, &common_kfunc_set);
2118}
2119
2120late_initcall(kfunc_init);