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v6.2
   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/* auditfilter.c -- filtering of audit events
   3 *
   4 * Copyright 2003-2004 Red Hat, Inc.
   5 * Copyright 2005 Hewlett-Packard Development Company, L.P.
   6 * Copyright 2005 IBM Corporation
   7 */
   8
   9#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  10
  11#include <linux/kernel.h>
  12#include <linux/audit.h>
  13#include <linux/kthread.h>
  14#include <linux/mutex.h>
  15#include <linux/fs.h>
  16#include <linux/namei.h>
  17#include <linux/netlink.h>
  18#include <linux/sched.h>
  19#include <linux/slab.h>
  20#include <linux/security.h>
  21#include <net/net_namespace.h>
  22#include <net/sock.h>
  23#include "audit.h"
  24
  25/*
  26 * Locking model:
  27 *
  28 * audit_filter_mutex:
  29 *		Synchronizes writes and blocking reads of audit's filterlist
  30 *		data.  Rcu is used to traverse the filterlist and access
  31 *		contents of structs audit_entry, audit_watch and opaque
  32 *		LSM rules during filtering.  If modified, these structures
  33 *		must be copied and replace their counterparts in the filterlist.
  34 *		An audit_parent struct is not accessed during filtering, so may
  35 *		be written directly provided audit_filter_mutex is held.
  36 */
  37
  38/* Audit filter lists, defined in <linux/audit.h> */
  39struct list_head audit_filter_list[AUDIT_NR_FILTERS] = {
  40	LIST_HEAD_INIT(audit_filter_list[0]),
  41	LIST_HEAD_INIT(audit_filter_list[1]),
  42	LIST_HEAD_INIT(audit_filter_list[2]),
  43	LIST_HEAD_INIT(audit_filter_list[3]),
  44	LIST_HEAD_INIT(audit_filter_list[4]),
  45	LIST_HEAD_INIT(audit_filter_list[5]),
  46	LIST_HEAD_INIT(audit_filter_list[6]),
  47	LIST_HEAD_INIT(audit_filter_list[7]),
  48#if AUDIT_NR_FILTERS != 8
  49#error Fix audit_filter_list initialiser
  50#endif
  51};
  52static struct list_head audit_rules_list[AUDIT_NR_FILTERS] = {
  53	LIST_HEAD_INIT(audit_rules_list[0]),
  54	LIST_HEAD_INIT(audit_rules_list[1]),
  55	LIST_HEAD_INIT(audit_rules_list[2]),
  56	LIST_HEAD_INIT(audit_rules_list[3]),
  57	LIST_HEAD_INIT(audit_rules_list[4]),
  58	LIST_HEAD_INIT(audit_rules_list[5]),
  59	LIST_HEAD_INIT(audit_rules_list[6]),
  60	LIST_HEAD_INIT(audit_rules_list[7]),
  61};
  62
  63DEFINE_MUTEX(audit_filter_mutex);
  64
  65static void audit_free_lsm_field(struct audit_field *f)
  66{
  67	switch (f->type) {
  68	case AUDIT_SUBJ_USER:
  69	case AUDIT_SUBJ_ROLE:
  70	case AUDIT_SUBJ_TYPE:
  71	case AUDIT_SUBJ_SEN:
  72	case AUDIT_SUBJ_CLR:
  73	case AUDIT_OBJ_USER:
  74	case AUDIT_OBJ_ROLE:
  75	case AUDIT_OBJ_TYPE:
  76	case AUDIT_OBJ_LEV_LOW:
  77	case AUDIT_OBJ_LEV_HIGH:
  78		kfree(f->lsm_str);
  79		security_audit_rule_free(f->lsm_rule);
  80	}
  81}
  82
  83static inline void audit_free_rule(struct audit_entry *e)
  84{
  85	int i;
  86	struct audit_krule *erule = &e->rule;
  87
  88	/* some rules don't have associated watches */
  89	if (erule->watch)
  90		audit_put_watch(erule->watch);
  91	if (erule->fields)
  92		for (i = 0; i < erule->field_count; i++)
  93			audit_free_lsm_field(&erule->fields[i]);
  94	kfree(erule->fields);
  95	kfree(erule->filterkey);
  96	kfree(e);
  97}
  98
  99void audit_free_rule_rcu(struct rcu_head *head)
 100{
 101	struct audit_entry *e = container_of(head, struct audit_entry, rcu);
 102	audit_free_rule(e);
 103}
 104
 105/* Initialize an audit filterlist entry. */
 106static inline struct audit_entry *audit_init_entry(u32 field_count)
 107{
 108	struct audit_entry *entry;
 109	struct audit_field *fields;
 110
 111	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 112	if (unlikely(!entry))
 113		return NULL;
 114
 115	fields = kcalloc(field_count, sizeof(*fields), GFP_KERNEL);
 116	if (unlikely(!fields)) {
 117		kfree(entry);
 118		return NULL;
 119	}
 120	entry->rule.fields = fields;
 121
 122	return entry;
 123}
 124
 125/* Unpack a filter field's string representation from user-space
 126 * buffer. */
 127char *audit_unpack_string(void **bufp, size_t *remain, size_t len)
 128{
 129	char *str;
 130
 131	if (!*bufp || (len == 0) || (len > *remain))
 132		return ERR_PTR(-EINVAL);
 133
 134	/* Of the currently implemented string fields, PATH_MAX
 135	 * defines the longest valid length.
 136	 */
 137	if (len > PATH_MAX)
 138		return ERR_PTR(-ENAMETOOLONG);
 139
 140	str = kmalloc(len + 1, GFP_KERNEL);
 141	if (unlikely(!str))
 142		return ERR_PTR(-ENOMEM);
 143
 144	memcpy(str, *bufp, len);
 145	str[len] = 0;
 146	*bufp += len;
 147	*remain -= len;
 148
 149	return str;
 150}
 151
 152/* Translate an inode field to kernel representation. */
 153static inline int audit_to_inode(struct audit_krule *krule,
 154				 struct audit_field *f)
 155{
 156	if ((krule->listnr != AUDIT_FILTER_EXIT &&
 157	     krule->listnr != AUDIT_FILTER_URING_EXIT) ||
 158	    krule->inode_f || krule->watch || krule->tree ||
 159	    (f->op != Audit_equal && f->op != Audit_not_equal))
 160		return -EINVAL;
 161
 162	krule->inode_f = f;
 163	return 0;
 164}
 165
 166static __u32 *classes[AUDIT_SYSCALL_CLASSES];
 167
 168int __init audit_register_class(int class, unsigned *list)
 169{
 170	__u32 *p = kcalloc(AUDIT_BITMASK_SIZE, sizeof(__u32), GFP_KERNEL);
 171	if (!p)
 172		return -ENOMEM;
 173	while (*list != ~0U) {
 174		unsigned n = *list++;
 175		if (n >= AUDIT_BITMASK_SIZE * 32 - AUDIT_SYSCALL_CLASSES) {
 176			kfree(p);
 177			return -EINVAL;
 178		}
 179		p[AUDIT_WORD(n)] |= AUDIT_BIT(n);
 180	}
 181	if (class >= AUDIT_SYSCALL_CLASSES || classes[class]) {
 182		kfree(p);
 183		return -EINVAL;
 184	}
 185	classes[class] = p;
 186	return 0;
 187}
 188
 189int audit_match_class(int class, unsigned syscall)
 190{
 191	if (unlikely(syscall >= AUDIT_BITMASK_SIZE * 32))
 192		return 0;
 193	if (unlikely(class >= AUDIT_SYSCALL_CLASSES || !classes[class]))
 194		return 0;
 195	return classes[class][AUDIT_WORD(syscall)] & AUDIT_BIT(syscall);
 196}
 197
 198#ifdef CONFIG_AUDITSYSCALL
 199static inline int audit_match_class_bits(int class, u32 *mask)
 200{
 201	int i;
 202
 203	if (classes[class]) {
 204		for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
 205			if (mask[i] & classes[class][i])
 206				return 0;
 207	}
 208	return 1;
 209}
 210
 211static int audit_match_signal(struct audit_entry *entry)
 212{
 213	struct audit_field *arch = entry->rule.arch_f;
 214
 215	if (!arch) {
 216		/* When arch is unspecified, we must check both masks on biarch
 217		 * as syscall number alone is ambiguous. */
 218		return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
 219					       entry->rule.mask) &&
 220			audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
 221					       entry->rule.mask));
 222	}
 223
 224	switch(audit_classify_arch(arch->val)) {
 225	case 0: /* native */
 226		return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
 227					       entry->rule.mask));
 228	case 1: /* 32bit on biarch */
 229		return (audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
 230					       entry->rule.mask));
 231	default:
 232		return 1;
 233	}
 234}
 235#endif
 236
 237/* Common user-space to kernel rule translation. */
 238static inline struct audit_entry *audit_to_entry_common(struct audit_rule_data *rule)
 239{
 240	unsigned listnr;
 241	struct audit_entry *entry;
 242	int i, err;
 243
 244	err = -EINVAL;
 245	listnr = rule->flags & ~AUDIT_FILTER_PREPEND;
 246	switch(listnr) {
 247	default:
 248		goto exit_err;
 249#ifdef CONFIG_AUDITSYSCALL
 250	case AUDIT_FILTER_ENTRY:
 251		pr_err("AUDIT_FILTER_ENTRY is deprecated\n");
 252		goto exit_err;
 253	case AUDIT_FILTER_EXIT:
 254	case AUDIT_FILTER_URING_EXIT:
 255	case AUDIT_FILTER_TASK:
 256#endif
 257	case AUDIT_FILTER_USER:
 258	case AUDIT_FILTER_EXCLUDE:
 259	case AUDIT_FILTER_FS:
 260		;
 261	}
 262	if (unlikely(rule->action == AUDIT_POSSIBLE)) {
 263		pr_err("AUDIT_POSSIBLE is deprecated\n");
 264		goto exit_err;
 265	}
 266	if (rule->action != AUDIT_NEVER && rule->action != AUDIT_ALWAYS)
 267		goto exit_err;
 268	if (rule->field_count > AUDIT_MAX_FIELDS)
 269		goto exit_err;
 270
 271	err = -ENOMEM;
 272	entry = audit_init_entry(rule->field_count);
 273	if (!entry)
 274		goto exit_err;
 275
 276	entry->rule.flags = rule->flags & AUDIT_FILTER_PREPEND;
 277	entry->rule.listnr = listnr;
 278	entry->rule.action = rule->action;
 279	entry->rule.field_count = rule->field_count;
 280
 281	for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
 282		entry->rule.mask[i] = rule->mask[i];
 283
 284	for (i = 0; i < AUDIT_SYSCALL_CLASSES; i++) {
 285		int bit = AUDIT_BITMASK_SIZE * 32 - i - 1;
 286		__u32 *p = &entry->rule.mask[AUDIT_WORD(bit)];
 287		__u32 *class;
 288
 289		if (!(*p & AUDIT_BIT(bit)))
 290			continue;
 291		*p &= ~AUDIT_BIT(bit);
 292		class = classes[i];
 293		if (class) {
 294			int j;
 295			for (j = 0; j < AUDIT_BITMASK_SIZE; j++)
 296				entry->rule.mask[j] |= class[j];
 297		}
 298	}
 299
 300	return entry;
 301
 302exit_err:
 303	return ERR_PTR(err);
 304}
 305
 306static u32 audit_ops[] =
 307{
 308	[Audit_equal] = AUDIT_EQUAL,
 309	[Audit_not_equal] = AUDIT_NOT_EQUAL,
 310	[Audit_bitmask] = AUDIT_BIT_MASK,
 311	[Audit_bittest] = AUDIT_BIT_TEST,
 312	[Audit_lt] = AUDIT_LESS_THAN,
 313	[Audit_gt] = AUDIT_GREATER_THAN,
 314	[Audit_le] = AUDIT_LESS_THAN_OR_EQUAL,
 315	[Audit_ge] = AUDIT_GREATER_THAN_OR_EQUAL,
 316};
 317
 318static u32 audit_to_op(u32 op)
 319{
 320	u32 n;
 321	for (n = Audit_equal; n < Audit_bad && audit_ops[n] != op; n++)
 322		;
 323	return n;
 324}
 325
 326/* check if an audit field is valid */
 327static int audit_field_valid(struct audit_entry *entry, struct audit_field *f)
 328{
 329	switch (f->type) {
 330	case AUDIT_MSGTYPE:
 331		if (entry->rule.listnr != AUDIT_FILTER_EXCLUDE &&
 332		    entry->rule.listnr != AUDIT_FILTER_USER)
 333			return -EINVAL;
 334		break;
 335	case AUDIT_FSTYPE:
 336		if (entry->rule.listnr != AUDIT_FILTER_FS)
 337			return -EINVAL;
 338		break;
 339	case AUDIT_PERM:
 340		if (entry->rule.listnr == AUDIT_FILTER_URING_EXIT)
 341			return -EINVAL;
 342		break;
 343	}
 344
 345	switch (entry->rule.listnr) {
 346	case AUDIT_FILTER_FS:
 347		switch(f->type) {
 348		case AUDIT_FSTYPE:
 349		case AUDIT_FILTERKEY:
 350			break;
 351		default:
 352			return -EINVAL;
 353		}
 354	}
 355
 356	/* Check for valid field type and op */
 357	switch (f->type) {
 358	case AUDIT_ARG0:
 359	case AUDIT_ARG1:
 360	case AUDIT_ARG2:
 361	case AUDIT_ARG3:
 362	case AUDIT_PERS: /* <uapi/linux/personality.h> */
 363	case AUDIT_DEVMINOR:
 364		/* all ops are valid */
 365		break;
 366	case AUDIT_UID:
 367	case AUDIT_EUID:
 368	case AUDIT_SUID:
 369	case AUDIT_FSUID:
 370	case AUDIT_LOGINUID:
 371	case AUDIT_OBJ_UID:
 372	case AUDIT_GID:
 373	case AUDIT_EGID:
 374	case AUDIT_SGID:
 375	case AUDIT_FSGID:
 376	case AUDIT_OBJ_GID:
 377	case AUDIT_PID:
 378	case AUDIT_MSGTYPE:
 379	case AUDIT_PPID:
 380	case AUDIT_DEVMAJOR:
 381	case AUDIT_EXIT:
 382	case AUDIT_SUCCESS:
 383	case AUDIT_INODE:
 384	case AUDIT_SESSIONID:
 385	case AUDIT_SUBJ_SEN:
 386	case AUDIT_SUBJ_CLR:
 387	case AUDIT_OBJ_LEV_LOW:
 388	case AUDIT_OBJ_LEV_HIGH:
 389	case AUDIT_SADDR_FAM:
 390		/* bit ops are only useful on syscall args */
 391		if (f->op == Audit_bitmask || f->op == Audit_bittest)
 392			return -EINVAL;
 393		break;
 394	case AUDIT_SUBJ_USER:
 395	case AUDIT_SUBJ_ROLE:
 396	case AUDIT_SUBJ_TYPE:
 397	case AUDIT_OBJ_USER:
 398	case AUDIT_OBJ_ROLE:
 399	case AUDIT_OBJ_TYPE:
 400	case AUDIT_WATCH:
 401	case AUDIT_DIR:
 402	case AUDIT_FILTERKEY:
 403	case AUDIT_LOGINUID_SET:
 404	case AUDIT_ARCH:
 405	case AUDIT_FSTYPE:
 406	case AUDIT_PERM:
 407	case AUDIT_FILETYPE:
 408	case AUDIT_FIELD_COMPARE:
 409	case AUDIT_EXE:
 410		/* only equal and not equal valid ops */
 411		if (f->op != Audit_not_equal && f->op != Audit_equal)
 412			return -EINVAL;
 413		break;
 414	default:
 415		/* field not recognized */
 416		return -EINVAL;
 417	}
 418
 419	/* Check for select valid field values */
 420	switch (f->type) {
 421	case AUDIT_LOGINUID_SET:
 422		if ((f->val != 0) && (f->val != 1))
 423			return -EINVAL;
 424		break;
 425	case AUDIT_PERM:
 426		if (f->val & ~15)
 427			return -EINVAL;
 428		break;
 429	case AUDIT_FILETYPE:
 430		if (f->val & ~S_IFMT)
 431			return -EINVAL;
 432		break;
 433	case AUDIT_FIELD_COMPARE:
 434		if (f->val > AUDIT_MAX_FIELD_COMPARE)
 435			return -EINVAL;
 436		break;
 437	case AUDIT_SADDR_FAM:
 438		if (f->val >= AF_MAX)
 439			return -EINVAL;
 440		break;
 441	default:
 442		break;
 443	}
 444
 445	return 0;
 446}
 447
 448/* Translate struct audit_rule_data to kernel's rule representation. */
 449static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
 450					       size_t datasz)
 451{
 452	int err = 0;
 453	struct audit_entry *entry;
 454	void *bufp;
 455	size_t remain = datasz - sizeof(struct audit_rule_data);
 456	int i;
 457	char *str;
 458	struct audit_fsnotify_mark *audit_mark;
 459
 460	entry = audit_to_entry_common(data);
 461	if (IS_ERR(entry))
 462		goto exit_nofree;
 463
 464	bufp = data->buf;
 465	for (i = 0; i < data->field_count; i++) {
 466		struct audit_field *f = &entry->rule.fields[i];
 467		u32 f_val;
 468
 469		err = -EINVAL;
 470
 471		f->op = audit_to_op(data->fieldflags[i]);
 472		if (f->op == Audit_bad)
 473			goto exit_free;
 474
 475		f->type = data->fields[i];
 476		f_val = data->values[i];
 477
 478		/* Support legacy tests for a valid loginuid */
 479		if ((f->type == AUDIT_LOGINUID) && (f_val == AUDIT_UID_UNSET)) {
 480			f->type = AUDIT_LOGINUID_SET;
 481			f_val = 0;
 482			entry->rule.pflags |= AUDIT_LOGINUID_LEGACY;
 483		}
 484
 485		err = audit_field_valid(entry, f);
 486		if (err)
 487			goto exit_free;
 488
 489		err = -EINVAL;
 490		switch (f->type) {
 491		case AUDIT_LOGINUID:
 492		case AUDIT_UID:
 493		case AUDIT_EUID:
 494		case AUDIT_SUID:
 495		case AUDIT_FSUID:
 496		case AUDIT_OBJ_UID:
 497			f->uid = make_kuid(current_user_ns(), f_val);
 498			if (!uid_valid(f->uid))
 499				goto exit_free;
 500			break;
 501		case AUDIT_GID:
 502		case AUDIT_EGID:
 503		case AUDIT_SGID:
 504		case AUDIT_FSGID:
 505		case AUDIT_OBJ_GID:
 506			f->gid = make_kgid(current_user_ns(), f_val);
 507			if (!gid_valid(f->gid))
 508				goto exit_free;
 509			break;
 510		case AUDIT_ARCH:
 511			f->val = f_val;
 512			entry->rule.arch_f = f;
 513			break;
 514		case AUDIT_SUBJ_USER:
 515		case AUDIT_SUBJ_ROLE:
 516		case AUDIT_SUBJ_TYPE:
 517		case AUDIT_SUBJ_SEN:
 518		case AUDIT_SUBJ_CLR:
 519		case AUDIT_OBJ_USER:
 520		case AUDIT_OBJ_ROLE:
 521		case AUDIT_OBJ_TYPE:
 522		case AUDIT_OBJ_LEV_LOW:
 523		case AUDIT_OBJ_LEV_HIGH:
 524			str = audit_unpack_string(&bufp, &remain, f_val);
 525			if (IS_ERR(str)) {
 526				err = PTR_ERR(str);
 527				goto exit_free;
 528			}
 529			entry->rule.buflen += f_val;
 530			f->lsm_str = str;
 531			err = security_audit_rule_init(f->type, f->op, str,
 532						       (void **)&f->lsm_rule);
 533			/* Keep currently invalid fields around in case they
 534			 * become valid after a policy reload. */
 535			if (err == -EINVAL) {
 536				pr_warn("audit rule for LSM \'%s\' is invalid\n",
 537					str);
 538				err = 0;
 539			} else if (err)
 540				goto exit_free;
 541			break;
 542		case AUDIT_WATCH:
 543			str = audit_unpack_string(&bufp, &remain, f_val);
 544			if (IS_ERR(str)) {
 545				err = PTR_ERR(str);
 546				goto exit_free;
 547			}
 548			err = audit_to_watch(&entry->rule, str, f_val, f->op);
 549			if (err) {
 550				kfree(str);
 551				goto exit_free;
 552			}
 553			entry->rule.buflen += f_val;
 554			break;
 555		case AUDIT_DIR:
 556			str = audit_unpack_string(&bufp, &remain, f_val);
 557			if (IS_ERR(str)) {
 558				err = PTR_ERR(str);
 559				goto exit_free;
 560			}
 561			err = audit_make_tree(&entry->rule, str, f->op);
 562			kfree(str);
 563			if (err)
 564				goto exit_free;
 565			entry->rule.buflen += f_val;
 566			break;
 567		case AUDIT_INODE:
 568			f->val = f_val;
 569			err = audit_to_inode(&entry->rule, f);
 570			if (err)
 571				goto exit_free;
 572			break;
 573		case AUDIT_FILTERKEY:
 574			if (entry->rule.filterkey || f_val > AUDIT_MAX_KEY_LEN)
 575				goto exit_free;
 576			str = audit_unpack_string(&bufp, &remain, f_val);
 577			if (IS_ERR(str)) {
 578				err = PTR_ERR(str);
 579				goto exit_free;
 580			}
 581			entry->rule.buflen += f_val;
 582			entry->rule.filterkey = str;
 583			break;
 584		case AUDIT_EXE:
 585			if (entry->rule.exe || f_val > PATH_MAX)
 586				goto exit_free;
 587			str = audit_unpack_string(&bufp, &remain, f_val);
 588			if (IS_ERR(str)) {
 589				err = PTR_ERR(str);
 590				goto exit_free;
 591			}
 592			audit_mark = audit_alloc_mark(&entry->rule, str, f_val);
 593			if (IS_ERR(audit_mark)) {
 594				kfree(str);
 595				err = PTR_ERR(audit_mark);
 596				goto exit_free;
 597			}
 598			entry->rule.buflen += f_val;
 599			entry->rule.exe = audit_mark;
 600			break;
 601		default:
 602			f->val = f_val;
 603			break;
 604		}
 605	}
 606
 607	if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal)
 608		entry->rule.inode_f = NULL;
 609
 610exit_nofree:
 611	return entry;
 612
 613exit_free:
 614	if (entry->rule.tree)
 615		audit_put_tree(entry->rule.tree); /* that's the temporary one */
 616	if (entry->rule.exe)
 617		audit_remove_mark(entry->rule.exe); /* that's the template one */
 618	audit_free_rule(entry);
 619	return ERR_PTR(err);
 620}
 621
 622/* Pack a filter field's string representation into data block. */
 623static inline size_t audit_pack_string(void **bufp, const char *str)
 624{
 625	size_t len = strlen(str);
 626
 627	memcpy(*bufp, str, len);
 628	*bufp += len;
 629
 630	return len;
 631}
 632
 633/* Translate kernel rule representation to struct audit_rule_data. */
 634static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule)
 635{
 636	struct audit_rule_data *data;
 637	void *bufp;
 638	int i;
 639
 640	data = kmalloc(struct_size(data, buf, krule->buflen), GFP_KERNEL);
 641	if (unlikely(!data))
 642		return NULL;
 643	memset(data, 0, sizeof(*data));
 644
 645	data->flags = krule->flags | krule->listnr;
 646	data->action = krule->action;
 647	data->field_count = krule->field_count;
 648	bufp = data->buf;
 649	for (i = 0; i < data->field_count; i++) {
 650		struct audit_field *f = &krule->fields[i];
 651
 652		data->fields[i] = f->type;
 653		data->fieldflags[i] = audit_ops[f->op];
 654		switch(f->type) {
 655		case AUDIT_SUBJ_USER:
 656		case AUDIT_SUBJ_ROLE:
 657		case AUDIT_SUBJ_TYPE:
 658		case AUDIT_SUBJ_SEN:
 659		case AUDIT_SUBJ_CLR:
 660		case AUDIT_OBJ_USER:
 661		case AUDIT_OBJ_ROLE:
 662		case AUDIT_OBJ_TYPE:
 663		case AUDIT_OBJ_LEV_LOW:
 664		case AUDIT_OBJ_LEV_HIGH:
 665			data->buflen += data->values[i] =
 666				audit_pack_string(&bufp, f->lsm_str);
 667			break;
 668		case AUDIT_WATCH:
 669			data->buflen += data->values[i] =
 670				audit_pack_string(&bufp,
 671						  audit_watch_path(krule->watch));
 672			break;
 673		case AUDIT_DIR:
 674			data->buflen += data->values[i] =
 675				audit_pack_string(&bufp,
 676						  audit_tree_path(krule->tree));
 677			break;
 678		case AUDIT_FILTERKEY:
 679			data->buflen += data->values[i] =
 680				audit_pack_string(&bufp, krule->filterkey);
 681			break;
 682		case AUDIT_EXE:
 683			data->buflen += data->values[i] =
 684				audit_pack_string(&bufp, audit_mark_path(krule->exe));
 685			break;
 686		case AUDIT_LOGINUID_SET:
 687			if (krule->pflags & AUDIT_LOGINUID_LEGACY && !f->val) {
 688				data->fields[i] = AUDIT_LOGINUID;
 689				data->values[i] = AUDIT_UID_UNSET;
 690				break;
 691			}
 692			fallthrough;	/* if set */
 693		default:
 694			data->values[i] = f->val;
 695		}
 696	}
 697	for (i = 0; i < AUDIT_BITMASK_SIZE; i++) data->mask[i] = krule->mask[i];
 698
 699	return data;
 700}
 701
 702/* Compare two rules in kernel format.  Considered success if rules
 703 * don't match. */
 704static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
 705{
 706	int i;
 707
 708	if (a->flags != b->flags ||
 709	    a->pflags != b->pflags ||
 710	    a->listnr != b->listnr ||
 711	    a->action != b->action ||
 712	    a->field_count != b->field_count)
 713		return 1;
 714
 715	for (i = 0; i < a->field_count; i++) {
 716		if (a->fields[i].type != b->fields[i].type ||
 717		    a->fields[i].op != b->fields[i].op)
 718			return 1;
 719
 720		switch(a->fields[i].type) {
 721		case AUDIT_SUBJ_USER:
 722		case AUDIT_SUBJ_ROLE:
 723		case AUDIT_SUBJ_TYPE:
 724		case AUDIT_SUBJ_SEN:
 725		case AUDIT_SUBJ_CLR:
 726		case AUDIT_OBJ_USER:
 727		case AUDIT_OBJ_ROLE:
 728		case AUDIT_OBJ_TYPE:
 729		case AUDIT_OBJ_LEV_LOW:
 730		case AUDIT_OBJ_LEV_HIGH:
 731			if (strcmp(a->fields[i].lsm_str, b->fields[i].lsm_str))
 732				return 1;
 733			break;
 734		case AUDIT_WATCH:
 735			if (strcmp(audit_watch_path(a->watch),
 736				   audit_watch_path(b->watch)))
 737				return 1;
 738			break;
 739		case AUDIT_DIR:
 740			if (strcmp(audit_tree_path(a->tree),
 741				   audit_tree_path(b->tree)))
 742				return 1;
 743			break;
 744		case AUDIT_FILTERKEY:
 745			/* both filterkeys exist based on above type compare */
 746			if (strcmp(a->filterkey, b->filterkey))
 747				return 1;
 748			break;
 749		case AUDIT_EXE:
 750			/* both paths exist based on above type compare */
 751			if (strcmp(audit_mark_path(a->exe),
 752				   audit_mark_path(b->exe)))
 753				return 1;
 754			break;
 755		case AUDIT_UID:
 756		case AUDIT_EUID:
 757		case AUDIT_SUID:
 758		case AUDIT_FSUID:
 759		case AUDIT_LOGINUID:
 760		case AUDIT_OBJ_UID:
 761			if (!uid_eq(a->fields[i].uid, b->fields[i].uid))
 762				return 1;
 763			break;
 764		case AUDIT_GID:
 765		case AUDIT_EGID:
 766		case AUDIT_SGID:
 767		case AUDIT_FSGID:
 768		case AUDIT_OBJ_GID:
 769			if (!gid_eq(a->fields[i].gid, b->fields[i].gid))
 770				return 1;
 771			break;
 772		default:
 773			if (a->fields[i].val != b->fields[i].val)
 774				return 1;
 775		}
 776	}
 777
 778	for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
 779		if (a->mask[i] != b->mask[i])
 780			return 1;
 781
 782	return 0;
 783}
 784
 785/* Duplicate LSM field information.  The lsm_rule is opaque, so must be
 786 * re-initialized. */
 787static inline int audit_dupe_lsm_field(struct audit_field *df,
 788					   struct audit_field *sf)
 789{
 790	int ret = 0;
 791	char *lsm_str;
 792
 793	/* our own copy of lsm_str */
 794	lsm_str = kstrdup(sf->lsm_str, GFP_KERNEL);
 795	if (unlikely(!lsm_str))
 796		return -ENOMEM;
 797	df->lsm_str = lsm_str;
 798
 799	/* our own (refreshed) copy of lsm_rule */
 800	ret = security_audit_rule_init(df->type, df->op, df->lsm_str,
 801				       (void **)&df->lsm_rule);
 802	/* Keep currently invalid fields around in case they
 803	 * become valid after a policy reload. */
 804	if (ret == -EINVAL) {
 805		pr_warn("audit rule for LSM \'%s\' is invalid\n",
 806			df->lsm_str);
 807		ret = 0;
 808	}
 809
 810	return ret;
 811}
 812
 813/* Duplicate an audit rule.  This will be a deep copy with the exception
 814 * of the watch - that pointer is carried over.  The LSM specific fields
 815 * will be updated in the copy.  The point is to be able to replace the old
 816 * rule with the new rule in the filterlist, then free the old rule.
 817 * The rlist element is undefined; list manipulations are handled apart from
 818 * the initial copy. */
 819struct audit_entry *audit_dupe_rule(struct audit_krule *old)
 820{
 821	u32 fcount = old->field_count;
 822	struct audit_entry *entry;
 823	struct audit_krule *new;
 824	char *fk;
 825	int i, err = 0;
 826
 827	entry = audit_init_entry(fcount);
 828	if (unlikely(!entry))
 829		return ERR_PTR(-ENOMEM);
 830
 831	new = &entry->rule;
 832	new->flags = old->flags;
 833	new->pflags = old->pflags;
 834	new->listnr = old->listnr;
 835	new->action = old->action;
 836	for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
 837		new->mask[i] = old->mask[i];
 838	new->prio = old->prio;
 839	new->buflen = old->buflen;
 840	new->inode_f = old->inode_f;
 841	new->field_count = old->field_count;
 842
 843	/*
 844	 * note that we are OK with not refcounting here; audit_match_tree()
 845	 * never dereferences tree and we can't get false positives there
 846	 * since we'd have to have rule gone from the list *and* removed
 847	 * before the chunks found by lookup had been allocated, i.e. before
 848	 * the beginning of list scan.
 849	 */
 850	new->tree = old->tree;
 851	memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount);
 852
 853	/* deep copy this information, updating the lsm_rule fields, because
 854	 * the originals will all be freed when the old rule is freed. */
 855	for (i = 0; i < fcount; i++) {
 856		switch (new->fields[i].type) {
 857		case AUDIT_SUBJ_USER:
 858		case AUDIT_SUBJ_ROLE:
 859		case AUDIT_SUBJ_TYPE:
 860		case AUDIT_SUBJ_SEN:
 861		case AUDIT_SUBJ_CLR:
 862		case AUDIT_OBJ_USER:
 863		case AUDIT_OBJ_ROLE:
 864		case AUDIT_OBJ_TYPE:
 865		case AUDIT_OBJ_LEV_LOW:
 866		case AUDIT_OBJ_LEV_HIGH:
 867			err = audit_dupe_lsm_field(&new->fields[i],
 868						       &old->fields[i]);
 869			break;
 870		case AUDIT_FILTERKEY:
 871			fk = kstrdup(old->filterkey, GFP_KERNEL);
 872			if (unlikely(!fk))
 873				err = -ENOMEM;
 874			else
 875				new->filterkey = fk;
 876			break;
 877		case AUDIT_EXE:
 878			err = audit_dupe_exe(new, old);
 879			break;
 880		}
 881		if (err) {
 882			if (new->exe)
 883				audit_remove_mark(new->exe);
 884			audit_free_rule(entry);
 885			return ERR_PTR(err);
 886		}
 887	}
 888
 889	if (old->watch) {
 890		audit_get_watch(old->watch);
 891		new->watch = old->watch;
 892	}
 893
 894	return entry;
 895}
 896
 897/* Find an existing audit rule.
 898 * Caller must hold audit_filter_mutex to prevent stale rule data. */
 899static struct audit_entry *audit_find_rule(struct audit_entry *entry,
 900					   struct list_head **p)
 901{
 902	struct audit_entry *e, *found = NULL;
 903	struct list_head *list;
 904	int h;
 905
 906	if (entry->rule.inode_f) {
 907		h = audit_hash_ino(entry->rule.inode_f->val);
 908		*p = list = &audit_inode_hash[h];
 909	} else if (entry->rule.watch) {
 910		/* we don't know the inode number, so must walk entire hash */
 911		for (h = 0; h < AUDIT_INODE_BUCKETS; h++) {
 912			list = &audit_inode_hash[h];
 913			list_for_each_entry(e, list, list)
 914				if (!audit_compare_rule(&entry->rule, &e->rule)) {
 915					found = e;
 916					goto out;
 917				}
 918		}
 919		goto out;
 920	} else {
 921		*p = list = &audit_filter_list[entry->rule.listnr];
 922	}
 923
 924	list_for_each_entry(e, list, list)
 925		if (!audit_compare_rule(&entry->rule, &e->rule)) {
 926			found = e;
 927			goto out;
 928		}
 929
 930out:
 931	return found;
 932}
 933
 934static u64 prio_low = ~0ULL/2;
 935static u64 prio_high = ~0ULL/2 - 1;
 936
 937/* Add rule to given filterlist if not a duplicate. */
 938static inline int audit_add_rule(struct audit_entry *entry)
 939{
 940	struct audit_entry *e;
 941	struct audit_watch *watch = entry->rule.watch;
 942	struct audit_tree *tree = entry->rule.tree;
 943	struct list_head *list;
 944	int err = 0;
 945#ifdef CONFIG_AUDITSYSCALL
 946	int dont_count = 0;
 947
 948	/* If any of these, don't count towards total */
 949	switch(entry->rule.listnr) {
 950	case AUDIT_FILTER_USER:
 951	case AUDIT_FILTER_EXCLUDE:
 952	case AUDIT_FILTER_FS:
 953		dont_count = 1;
 954	}
 955#endif
 956
 957	mutex_lock(&audit_filter_mutex);
 958	e = audit_find_rule(entry, &list);
 959	if (e) {
 960		mutex_unlock(&audit_filter_mutex);
 961		err = -EEXIST;
 962		/* normally audit_add_tree_rule() will free it on failure */
 963		if (tree)
 964			audit_put_tree(tree);
 965		return err;
 966	}
 967
 968	if (watch) {
 969		/* audit_filter_mutex is dropped and re-taken during this call */
 970		err = audit_add_watch(&entry->rule, &list);
 971		if (err) {
 972			mutex_unlock(&audit_filter_mutex);
 973			/*
 974			 * normally audit_add_tree_rule() will free it
 975			 * on failure
 976			 */
 977			if (tree)
 978				audit_put_tree(tree);
 979			return err;
 980		}
 981	}
 982	if (tree) {
 983		err = audit_add_tree_rule(&entry->rule);
 984		if (err) {
 985			mutex_unlock(&audit_filter_mutex);
 986			return err;
 987		}
 988	}
 989
 990	entry->rule.prio = ~0ULL;
 991	if (entry->rule.listnr == AUDIT_FILTER_EXIT ||
 992	    entry->rule.listnr == AUDIT_FILTER_URING_EXIT) {
 993		if (entry->rule.flags & AUDIT_FILTER_PREPEND)
 994			entry->rule.prio = ++prio_high;
 995		else
 996			entry->rule.prio = --prio_low;
 997	}
 998
 999	if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
1000		list_add(&entry->rule.list,
1001			 &audit_rules_list[entry->rule.listnr]);
1002		list_add_rcu(&entry->list, list);
1003		entry->rule.flags &= ~AUDIT_FILTER_PREPEND;
1004	} else {
1005		list_add_tail(&entry->rule.list,
1006			      &audit_rules_list[entry->rule.listnr]);
1007		list_add_tail_rcu(&entry->list, list);
1008	}
1009#ifdef CONFIG_AUDITSYSCALL
1010	if (!dont_count)
1011		audit_n_rules++;
1012
1013	if (!audit_match_signal(entry))
1014		audit_signals++;
1015#endif
1016	mutex_unlock(&audit_filter_mutex);
1017
1018	return err;
1019}
1020
1021/* Remove an existing rule from filterlist. */
1022int audit_del_rule(struct audit_entry *entry)
1023{
1024	struct audit_entry  *e;
1025	struct audit_tree *tree = entry->rule.tree;
1026	struct list_head *list;
1027	int ret = 0;
1028#ifdef CONFIG_AUDITSYSCALL
1029	int dont_count = 0;
1030
1031	/* If any of these, don't count towards total */
1032	switch(entry->rule.listnr) {
1033	case AUDIT_FILTER_USER:
1034	case AUDIT_FILTER_EXCLUDE:
1035	case AUDIT_FILTER_FS:
1036		dont_count = 1;
1037	}
1038#endif
1039
1040	mutex_lock(&audit_filter_mutex);
1041	e = audit_find_rule(entry, &list);
1042	if (!e) {
1043		ret = -ENOENT;
1044		goto out;
1045	}
1046
1047	if (e->rule.watch)
1048		audit_remove_watch_rule(&e->rule);
1049
1050	if (e->rule.tree)
1051		audit_remove_tree_rule(&e->rule);
1052
1053	if (e->rule.exe)
1054		audit_remove_mark_rule(&e->rule);
1055
1056#ifdef CONFIG_AUDITSYSCALL
1057	if (!dont_count)
1058		audit_n_rules--;
1059
1060	if (!audit_match_signal(entry))
1061		audit_signals--;
1062#endif
1063
1064	list_del_rcu(&e->list);
1065	list_del(&e->rule.list);
1066	call_rcu(&e->rcu, audit_free_rule_rcu);
1067
1068out:
1069	mutex_unlock(&audit_filter_mutex);
1070
1071	if (tree)
1072		audit_put_tree(tree);	/* that's the temporary one */
1073
1074	return ret;
1075}
1076
1077/* List rules using struct audit_rule_data. */
1078static void audit_list_rules(int seq, struct sk_buff_head *q)
1079{
1080	struct sk_buff *skb;
1081	struct audit_krule *r;
1082	int i;
1083
1084	/* This is a blocking read, so use audit_filter_mutex instead of rcu
1085	 * iterator to sync with list writers. */
1086	for (i=0; i<AUDIT_NR_FILTERS; i++) {
1087		list_for_each_entry(r, &audit_rules_list[i], list) {
1088			struct audit_rule_data *data;
1089
1090			data = audit_krule_to_data(r);
1091			if (unlikely(!data))
1092				break;
1093			skb = audit_make_reply(seq, AUDIT_LIST_RULES, 0, 1,
1094					       data,
1095					       struct_size(data, buf, data->buflen));
1096			if (skb)
1097				skb_queue_tail(q, skb);
1098			kfree(data);
1099		}
1100	}
1101	skb = audit_make_reply(seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);
1102	if (skb)
1103		skb_queue_tail(q, skb);
1104}
1105
1106/* Log rule additions and removals */
1107static void audit_log_rule_change(char *action, struct audit_krule *rule, int res)
1108{
1109	struct audit_buffer *ab;
1110
1111	if (!audit_enabled)
1112		return;
1113
1114	ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_CONFIG_CHANGE);
1115	if (!ab)
1116		return;
1117	audit_log_session_info(ab);
1118	audit_log_task_context(ab);
1119	audit_log_format(ab, " op=%s", action);
1120	audit_log_key(ab, rule->filterkey);
1121	audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
1122	audit_log_end(ab);
1123}
1124
1125/**
1126 * audit_rule_change - apply all rules to the specified message type
1127 * @type: audit message type
1128 * @seq: netlink audit message sequence (serial) number
1129 * @data: payload data
1130 * @datasz: size of payload data
1131 */
1132int audit_rule_change(int type, int seq, void *data, size_t datasz)
1133{
1134	int err = 0;
1135	struct audit_entry *entry;
1136
1137	switch (type) {
1138	case AUDIT_ADD_RULE:
1139		entry = audit_data_to_entry(data, datasz);
1140		if (IS_ERR(entry))
1141			return PTR_ERR(entry);
1142		err = audit_add_rule(entry);
1143		audit_log_rule_change("add_rule", &entry->rule, !err);
1144		break;
1145	case AUDIT_DEL_RULE:
1146		entry = audit_data_to_entry(data, datasz);
1147		if (IS_ERR(entry))
1148			return PTR_ERR(entry);
1149		err = audit_del_rule(entry);
1150		audit_log_rule_change("remove_rule", &entry->rule, !err);
1151		break;
1152	default:
1153		WARN_ON(1);
1154		return -EINVAL;
1155	}
1156
1157	if (err || type == AUDIT_DEL_RULE) {
1158		if (entry->rule.exe)
1159			audit_remove_mark(entry->rule.exe);
1160		audit_free_rule(entry);
1161	}
1162
1163	return err;
1164}
1165
1166/**
1167 * audit_list_rules_send - list the audit rules
1168 * @request_skb: skb of request we are replying to (used to target the reply)
1169 * @seq: netlink audit message sequence (serial) number
1170 */
1171int audit_list_rules_send(struct sk_buff *request_skb, int seq)
1172{
1173	struct task_struct *tsk;
1174	struct audit_netlink_list *dest;
1175
1176	/* We can't just spew out the rules here because we might fill
1177	 * the available socket buffer space and deadlock waiting for
1178	 * auditctl to read from it... which isn't ever going to
1179	 * happen if we're actually running in the context of auditctl
1180	 * trying to _send_ the stuff */
1181
1182	dest = kmalloc(sizeof(*dest), GFP_KERNEL);
1183	if (!dest)
1184		return -ENOMEM;
1185	dest->net = get_net(sock_net(NETLINK_CB(request_skb).sk));
1186	dest->portid = NETLINK_CB(request_skb).portid;
1187	skb_queue_head_init(&dest->q);
1188
1189	mutex_lock(&audit_filter_mutex);
1190	audit_list_rules(seq, &dest->q);
1191	mutex_unlock(&audit_filter_mutex);
1192
1193	tsk = kthread_run(audit_send_list_thread, dest, "audit_send_list");
1194	if (IS_ERR(tsk)) {
1195		skb_queue_purge(&dest->q);
1196		put_net(dest->net);
1197		kfree(dest);
1198		return PTR_ERR(tsk);
1199	}
1200
1201	return 0;
1202}
1203
1204int audit_comparator(u32 left, u32 op, u32 right)
1205{
1206	switch (op) {
1207	case Audit_equal:
1208		return (left == right);
1209	case Audit_not_equal:
1210		return (left != right);
1211	case Audit_lt:
1212		return (left < right);
1213	case Audit_le:
1214		return (left <= right);
1215	case Audit_gt:
1216		return (left > right);
1217	case Audit_ge:
1218		return (left >= right);
1219	case Audit_bitmask:
1220		return (left & right);
1221	case Audit_bittest:
1222		return ((left & right) == right);
1223	default:
1224		return 0;
1225	}
1226}
1227
1228int audit_uid_comparator(kuid_t left, u32 op, kuid_t right)
1229{
1230	switch (op) {
1231	case Audit_equal:
1232		return uid_eq(left, right);
1233	case Audit_not_equal:
1234		return !uid_eq(left, right);
1235	case Audit_lt:
1236		return uid_lt(left, right);
1237	case Audit_le:
1238		return uid_lte(left, right);
1239	case Audit_gt:
1240		return uid_gt(left, right);
1241	case Audit_ge:
1242		return uid_gte(left, right);
1243	case Audit_bitmask:
1244	case Audit_bittest:
1245	default:
1246		return 0;
1247	}
1248}
1249
1250int audit_gid_comparator(kgid_t left, u32 op, kgid_t right)
1251{
1252	switch (op) {
1253	case Audit_equal:
1254		return gid_eq(left, right);
1255	case Audit_not_equal:
1256		return !gid_eq(left, right);
1257	case Audit_lt:
1258		return gid_lt(left, right);
1259	case Audit_le:
1260		return gid_lte(left, right);
1261	case Audit_gt:
1262		return gid_gt(left, right);
1263	case Audit_ge:
1264		return gid_gte(left, right);
1265	case Audit_bitmask:
1266	case Audit_bittest:
1267	default:
1268		return 0;
1269	}
1270}
1271
1272/**
1273 * parent_len - find the length of the parent portion of a pathname
1274 * @path: pathname of which to determine length
1275 */
1276int parent_len(const char *path)
1277{
1278	int plen;
1279	const char *p;
1280
1281	plen = strlen(path);
1282
1283	if (plen == 0)
1284		return plen;
1285
1286	/* disregard trailing slashes */
1287	p = path + plen - 1;
1288	while ((*p == '/') && (p > path))
1289		p--;
1290
1291	/* walk backward until we find the next slash or hit beginning */
1292	while ((*p != '/') && (p > path))
1293		p--;
1294
1295	/* did we find a slash? Then increment to include it in path */
1296	if (*p == '/')
1297		p++;
1298
1299	return p - path;
1300}
1301
1302/**
1303 * audit_compare_dname_path - compare given dentry name with last component in
1304 * 			      given path. Return of 0 indicates a match.
1305 * @dname:	dentry name that we're comparing
1306 * @path:	full pathname that we're comparing
1307 * @parentlen:	length of the parent if known. Passing in AUDIT_NAME_FULL
1308 * 		here indicates that we must compute this value.
1309 */
1310int audit_compare_dname_path(const struct qstr *dname, const char *path, int parentlen)
1311{
1312	int dlen, pathlen;
1313	const char *p;
1314
1315	dlen = dname->len;
1316	pathlen = strlen(path);
1317	if (pathlen < dlen)
1318		return 1;
1319
1320	parentlen = parentlen == AUDIT_NAME_FULL ? parent_len(path) : parentlen;
1321	if (pathlen - parentlen != dlen)
1322		return 1;
1323
1324	p = path + parentlen;
1325
1326	return strncmp(p, dname->name, dlen);
1327}
1328
1329int audit_filter(int msgtype, unsigned int listtype)
1330{
1331	struct audit_entry *e;
1332	int ret = 1; /* Audit by default */
1333
1334	rcu_read_lock();
1335	list_for_each_entry_rcu(e, &audit_filter_list[listtype], list) {
1336		int i, result = 0;
1337
1338		for (i = 0; i < e->rule.field_count; i++) {
1339			struct audit_field *f = &e->rule.fields[i];
1340			pid_t pid;
1341			u32 sid;
1342
1343			switch (f->type) {
1344			case AUDIT_PID:
1345				pid = task_pid_nr(current);
1346				result = audit_comparator(pid, f->op, f->val);
1347				break;
1348			case AUDIT_UID:
1349				result = audit_uid_comparator(current_uid(), f->op, f->uid);
1350				break;
1351			case AUDIT_GID:
1352				result = audit_gid_comparator(current_gid(), f->op, f->gid);
1353				break;
1354			case AUDIT_LOGINUID:
1355				result = audit_uid_comparator(audit_get_loginuid(current),
1356							      f->op, f->uid);
1357				break;
1358			case AUDIT_LOGINUID_SET:
1359				result = audit_comparator(audit_loginuid_set(current),
1360							  f->op, f->val);
1361				break;
1362			case AUDIT_MSGTYPE:
1363				result = audit_comparator(msgtype, f->op, f->val);
1364				break;
1365			case AUDIT_SUBJ_USER:
1366			case AUDIT_SUBJ_ROLE:
1367			case AUDIT_SUBJ_TYPE:
1368			case AUDIT_SUBJ_SEN:
1369			case AUDIT_SUBJ_CLR:
1370				if (f->lsm_rule) {
1371					security_current_getsecid_subj(&sid);
1372					result = security_audit_rule_match(sid,
1373						   f->type, f->op, f->lsm_rule);
1374				}
1375				break;
1376			case AUDIT_EXE:
1377				result = audit_exe_compare(current, e->rule.exe);
1378				if (f->op == Audit_not_equal)
1379					result = !result;
1380				break;
1381			default:
1382				goto unlock_and_return;
1383			}
1384			if (result < 0) /* error */
1385				goto unlock_and_return;
1386			if (!result)
1387				break;
1388		}
1389		if (result > 0) {
1390			if (e->rule.action == AUDIT_NEVER || listtype == AUDIT_FILTER_EXCLUDE)
1391				ret = 0;
1392			break;
1393		}
1394	}
1395unlock_and_return:
1396	rcu_read_unlock();
1397	return ret;
1398}
1399
1400static int update_lsm_rule(struct audit_krule *r)
1401{
1402	struct audit_entry *entry = container_of(r, struct audit_entry, rule);
1403	struct audit_entry *nentry;
1404	int err = 0;
1405
1406	if (!security_audit_rule_known(r))
1407		return 0;
1408
1409	nentry = audit_dupe_rule(r);
1410	if (entry->rule.exe)
1411		audit_remove_mark(entry->rule.exe);
1412	if (IS_ERR(nentry)) {
1413		/* save the first error encountered for the
1414		 * return value */
1415		err = PTR_ERR(nentry);
1416		audit_panic("error updating LSM filters");
1417		if (r->watch)
1418			list_del(&r->rlist);
1419		list_del_rcu(&entry->list);
1420		list_del(&r->list);
1421	} else {
1422		if (r->watch || r->tree)
1423			list_replace_init(&r->rlist, &nentry->rule.rlist);
1424		list_replace_rcu(&entry->list, &nentry->list);
1425		list_replace(&r->list, &nentry->rule.list);
1426	}
1427	call_rcu(&entry->rcu, audit_free_rule_rcu);
1428
1429	return err;
1430}
1431
1432/* This function will re-initialize the lsm_rule field of all applicable rules.
1433 * It will traverse the filter lists serarching for rules that contain LSM
1434 * specific filter fields.  When such a rule is found, it is copied, the
1435 * LSM field is re-initialized, and the old rule is replaced with the
1436 * updated rule. */
1437int audit_update_lsm_rules(void)
1438{
1439	struct audit_krule *r, *n;
1440	int i, err = 0;
1441
1442	/* audit_filter_mutex synchronizes the writers */
1443	mutex_lock(&audit_filter_mutex);
1444
1445	for (i = 0; i < AUDIT_NR_FILTERS; i++) {
1446		list_for_each_entry_safe(r, n, &audit_rules_list[i], list) {
1447			int res = update_lsm_rule(r);
1448			if (!err)
1449				err = res;
1450		}
1451	}
1452	mutex_unlock(&audit_filter_mutex);
1453
1454	return err;
1455}
v5.9
   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/* auditfilter.c -- filtering of audit events
   3 *
   4 * Copyright 2003-2004 Red Hat, Inc.
   5 * Copyright 2005 Hewlett-Packard Development Company, L.P.
   6 * Copyright 2005 IBM Corporation
   7 */
   8
   9#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  10
  11#include <linux/kernel.h>
  12#include <linux/audit.h>
  13#include <linux/kthread.h>
  14#include <linux/mutex.h>
  15#include <linux/fs.h>
  16#include <linux/namei.h>
  17#include <linux/netlink.h>
  18#include <linux/sched.h>
  19#include <linux/slab.h>
  20#include <linux/security.h>
  21#include <net/net_namespace.h>
  22#include <net/sock.h>
  23#include "audit.h"
  24
  25/*
  26 * Locking model:
  27 *
  28 * audit_filter_mutex:
  29 *		Synchronizes writes and blocking reads of audit's filterlist
  30 *		data.  Rcu is used to traverse the filterlist and access
  31 *		contents of structs audit_entry, audit_watch and opaque
  32 *		LSM rules during filtering.  If modified, these structures
  33 *		must be copied and replace their counterparts in the filterlist.
  34 *		An audit_parent struct is not accessed during filtering, so may
  35 *		be written directly provided audit_filter_mutex is held.
  36 */
  37
  38/* Audit filter lists, defined in <linux/audit.h> */
  39struct list_head audit_filter_list[AUDIT_NR_FILTERS] = {
  40	LIST_HEAD_INIT(audit_filter_list[0]),
  41	LIST_HEAD_INIT(audit_filter_list[1]),
  42	LIST_HEAD_INIT(audit_filter_list[2]),
  43	LIST_HEAD_INIT(audit_filter_list[3]),
  44	LIST_HEAD_INIT(audit_filter_list[4]),
  45	LIST_HEAD_INIT(audit_filter_list[5]),
  46	LIST_HEAD_INIT(audit_filter_list[6]),
  47#if AUDIT_NR_FILTERS != 7
 
  48#error Fix audit_filter_list initialiser
  49#endif
  50};
  51static struct list_head audit_rules_list[AUDIT_NR_FILTERS] = {
  52	LIST_HEAD_INIT(audit_rules_list[0]),
  53	LIST_HEAD_INIT(audit_rules_list[1]),
  54	LIST_HEAD_INIT(audit_rules_list[2]),
  55	LIST_HEAD_INIT(audit_rules_list[3]),
  56	LIST_HEAD_INIT(audit_rules_list[4]),
  57	LIST_HEAD_INIT(audit_rules_list[5]),
  58	LIST_HEAD_INIT(audit_rules_list[6]),
 
  59};
  60
  61DEFINE_MUTEX(audit_filter_mutex);
  62
  63static void audit_free_lsm_field(struct audit_field *f)
  64{
  65	switch (f->type) {
  66	case AUDIT_SUBJ_USER:
  67	case AUDIT_SUBJ_ROLE:
  68	case AUDIT_SUBJ_TYPE:
  69	case AUDIT_SUBJ_SEN:
  70	case AUDIT_SUBJ_CLR:
  71	case AUDIT_OBJ_USER:
  72	case AUDIT_OBJ_ROLE:
  73	case AUDIT_OBJ_TYPE:
  74	case AUDIT_OBJ_LEV_LOW:
  75	case AUDIT_OBJ_LEV_HIGH:
  76		kfree(f->lsm_str);
  77		security_audit_rule_free(f->lsm_rule);
  78	}
  79}
  80
  81static inline void audit_free_rule(struct audit_entry *e)
  82{
  83	int i;
  84	struct audit_krule *erule = &e->rule;
  85
  86	/* some rules don't have associated watches */
  87	if (erule->watch)
  88		audit_put_watch(erule->watch);
  89	if (erule->fields)
  90		for (i = 0; i < erule->field_count; i++)
  91			audit_free_lsm_field(&erule->fields[i]);
  92	kfree(erule->fields);
  93	kfree(erule->filterkey);
  94	kfree(e);
  95}
  96
  97void audit_free_rule_rcu(struct rcu_head *head)
  98{
  99	struct audit_entry *e = container_of(head, struct audit_entry, rcu);
 100	audit_free_rule(e);
 101}
 102
 103/* Initialize an audit filterlist entry. */
 104static inline struct audit_entry *audit_init_entry(u32 field_count)
 105{
 106	struct audit_entry *entry;
 107	struct audit_field *fields;
 108
 109	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 110	if (unlikely(!entry))
 111		return NULL;
 112
 113	fields = kcalloc(field_count, sizeof(*fields), GFP_KERNEL);
 114	if (unlikely(!fields)) {
 115		kfree(entry);
 116		return NULL;
 117	}
 118	entry->rule.fields = fields;
 119
 120	return entry;
 121}
 122
 123/* Unpack a filter field's string representation from user-space
 124 * buffer. */
 125char *audit_unpack_string(void **bufp, size_t *remain, size_t len)
 126{
 127	char *str;
 128
 129	if (!*bufp || (len == 0) || (len > *remain))
 130		return ERR_PTR(-EINVAL);
 131
 132	/* Of the currently implemented string fields, PATH_MAX
 133	 * defines the longest valid length.
 134	 */
 135	if (len > PATH_MAX)
 136		return ERR_PTR(-ENAMETOOLONG);
 137
 138	str = kmalloc(len + 1, GFP_KERNEL);
 139	if (unlikely(!str))
 140		return ERR_PTR(-ENOMEM);
 141
 142	memcpy(str, *bufp, len);
 143	str[len] = 0;
 144	*bufp += len;
 145	*remain -= len;
 146
 147	return str;
 148}
 149
 150/* Translate an inode field to kernel representation. */
 151static inline int audit_to_inode(struct audit_krule *krule,
 152				 struct audit_field *f)
 153{
 154	if (krule->listnr != AUDIT_FILTER_EXIT ||
 
 155	    krule->inode_f || krule->watch || krule->tree ||
 156	    (f->op != Audit_equal && f->op != Audit_not_equal))
 157		return -EINVAL;
 158
 159	krule->inode_f = f;
 160	return 0;
 161}
 162
 163static __u32 *classes[AUDIT_SYSCALL_CLASSES];
 164
 165int __init audit_register_class(int class, unsigned *list)
 166{
 167	__u32 *p = kcalloc(AUDIT_BITMASK_SIZE, sizeof(__u32), GFP_KERNEL);
 168	if (!p)
 169		return -ENOMEM;
 170	while (*list != ~0U) {
 171		unsigned n = *list++;
 172		if (n >= AUDIT_BITMASK_SIZE * 32 - AUDIT_SYSCALL_CLASSES) {
 173			kfree(p);
 174			return -EINVAL;
 175		}
 176		p[AUDIT_WORD(n)] |= AUDIT_BIT(n);
 177	}
 178	if (class >= AUDIT_SYSCALL_CLASSES || classes[class]) {
 179		kfree(p);
 180		return -EINVAL;
 181	}
 182	classes[class] = p;
 183	return 0;
 184}
 185
 186int audit_match_class(int class, unsigned syscall)
 187{
 188	if (unlikely(syscall >= AUDIT_BITMASK_SIZE * 32))
 189		return 0;
 190	if (unlikely(class >= AUDIT_SYSCALL_CLASSES || !classes[class]))
 191		return 0;
 192	return classes[class][AUDIT_WORD(syscall)] & AUDIT_BIT(syscall);
 193}
 194
 195#ifdef CONFIG_AUDITSYSCALL
 196static inline int audit_match_class_bits(int class, u32 *mask)
 197{
 198	int i;
 199
 200	if (classes[class]) {
 201		for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
 202			if (mask[i] & classes[class][i])
 203				return 0;
 204	}
 205	return 1;
 206}
 207
 208static int audit_match_signal(struct audit_entry *entry)
 209{
 210	struct audit_field *arch = entry->rule.arch_f;
 211
 212	if (!arch) {
 213		/* When arch is unspecified, we must check both masks on biarch
 214		 * as syscall number alone is ambiguous. */
 215		return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
 216					       entry->rule.mask) &&
 217			audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
 218					       entry->rule.mask));
 219	}
 220
 221	switch(audit_classify_arch(arch->val)) {
 222	case 0: /* native */
 223		return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
 224					       entry->rule.mask));
 225	case 1: /* 32bit on biarch */
 226		return (audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
 227					       entry->rule.mask));
 228	default:
 229		return 1;
 230	}
 231}
 232#endif
 233
 234/* Common user-space to kernel rule translation. */
 235static inline struct audit_entry *audit_to_entry_common(struct audit_rule_data *rule)
 236{
 237	unsigned listnr;
 238	struct audit_entry *entry;
 239	int i, err;
 240
 241	err = -EINVAL;
 242	listnr = rule->flags & ~AUDIT_FILTER_PREPEND;
 243	switch(listnr) {
 244	default:
 245		goto exit_err;
 246#ifdef CONFIG_AUDITSYSCALL
 247	case AUDIT_FILTER_ENTRY:
 248		pr_err("AUDIT_FILTER_ENTRY is deprecated\n");
 249		goto exit_err;
 250	case AUDIT_FILTER_EXIT:
 
 251	case AUDIT_FILTER_TASK:
 252#endif
 253	case AUDIT_FILTER_USER:
 254	case AUDIT_FILTER_EXCLUDE:
 255	case AUDIT_FILTER_FS:
 256		;
 257	}
 258	if (unlikely(rule->action == AUDIT_POSSIBLE)) {
 259		pr_err("AUDIT_POSSIBLE is deprecated\n");
 260		goto exit_err;
 261	}
 262	if (rule->action != AUDIT_NEVER && rule->action != AUDIT_ALWAYS)
 263		goto exit_err;
 264	if (rule->field_count > AUDIT_MAX_FIELDS)
 265		goto exit_err;
 266
 267	err = -ENOMEM;
 268	entry = audit_init_entry(rule->field_count);
 269	if (!entry)
 270		goto exit_err;
 271
 272	entry->rule.flags = rule->flags & AUDIT_FILTER_PREPEND;
 273	entry->rule.listnr = listnr;
 274	entry->rule.action = rule->action;
 275	entry->rule.field_count = rule->field_count;
 276
 277	for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
 278		entry->rule.mask[i] = rule->mask[i];
 279
 280	for (i = 0; i < AUDIT_SYSCALL_CLASSES; i++) {
 281		int bit = AUDIT_BITMASK_SIZE * 32 - i - 1;
 282		__u32 *p = &entry->rule.mask[AUDIT_WORD(bit)];
 283		__u32 *class;
 284
 285		if (!(*p & AUDIT_BIT(bit)))
 286			continue;
 287		*p &= ~AUDIT_BIT(bit);
 288		class = classes[i];
 289		if (class) {
 290			int j;
 291			for (j = 0; j < AUDIT_BITMASK_SIZE; j++)
 292				entry->rule.mask[j] |= class[j];
 293		}
 294	}
 295
 296	return entry;
 297
 298exit_err:
 299	return ERR_PTR(err);
 300}
 301
 302static u32 audit_ops[] =
 303{
 304	[Audit_equal] = AUDIT_EQUAL,
 305	[Audit_not_equal] = AUDIT_NOT_EQUAL,
 306	[Audit_bitmask] = AUDIT_BIT_MASK,
 307	[Audit_bittest] = AUDIT_BIT_TEST,
 308	[Audit_lt] = AUDIT_LESS_THAN,
 309	[Audit_gt] = AUDIT_GREATER_THAN,
 310	[Audit_le] = AUDIT_LESS_THAN_OR_EQUAL,
 311	[Audit_ge] = AUDIT_GREATER_THAN_OR_EQUAL,
 312};
 313
 314static u32 audit_to_op(u32 op)
 315{
 316	u32 n;
 317	for (n = Audit_equal; n < Audit_bad && audit_ops[n] != op; n++)
 318		;
 319	return n;
 320}
 321
 322/* check if an audit field is valid */
 323static int audit_field_valid(struct audit_entry *entry, struct audit_field *f)
 324{
 325	switch (f->type) {
 326	case AUDIT_MSGTYPE:
 327		if (entry->rule.listnr != AUDIT_FILTER_EXCLUDE &&
 328		    entry->rule.listnr != AUDIT_FILTER_USER)
 329			return -EINVAL;
 330		break;
 331	case AUDIT_FSTYPE:
 332		if (entry->rule.listnr != AUDIT_FILTER_FS)
 333			return -EINVAL;
 334		break;
 
 
 
 
 335	}
 336
 337	switch (entry->rule.listnr) {
 338	case AUDIT_FILTER_FS:
 339		switch(f->type) {
 340		case AUDIT_FSTYPE:
 341		case AUDIT_FILTERKEY:
 342			break;
 343		default:
 344			return -EINVAL;
 345		}
 346	}
 347
 348	/* Check for valid field type and op */
 349	switch (f->type) {
 350	case AUDIT_ARG0:
 351	case AUDIT_ARG1:
 352	case AUDIT_ARG2:
 353	case AUDIT_ARG3:
 354	case AUDIT_PERS: /* <uapi/linux/personality.h> */
 355	case AUDIT_DEVMINOR:
 356		/* all ops are valid */
 357		break;
 358	case AUDIT_UID:
 359	case AUDIT_EUID:
 360	case AUDIT_SUID:
 361	case AUDIT_FSUID:
 362	case AUDIT_LOGINUID:
 363	case AUDIT_OBJ_UID:
 364	case AUDIT_GID:
 365	case AUDIT_EGID:
 366	case AUDIT_SGID:
 367	case AUDIT_FSGID:
 368	case AUDIT_OBJ_GID:
 369	case AUDIT_PID:
 370	case AUDIT_MSGTYPE:
 371	case AUDIT_PPID:
 372	case AUDIT_DEVMAJOR:
 373	case AUDIT_EXIT:
 374	case AUDIT_SUCCESS:
 375	case AUDIT_INODE:
 376	case AUDIT_SESSIONID:
 377	case AUDIT_SUBJ_SEN:
 378	case AUDIT_SUBJ_CLR:
 379	case AUDIT_OBJ_LEV_LOW:
 380	case AUDIT_OBJ_LEV_HIGH:
 381	case AUDIT_SADDR_FAM:
 382		/* bit ops are only useful on syscall args */
 383		if (f->op == Audit_bitmask || f->op == Audit_bittest)
 384			return -EINVAL;
 385		break;
 386	case AUDIT_SUBJ_USER:
 387	case AUDIT_SUBJ_ROLE:
 388	case AUDIT_SUBJ_TYPE:
 389	case AUDIT_OBJ_USER:
 390	case AUDIT_OBJ_ROLE:
 391	case AUDIT_OBJ_TYPE:
 392	case AUDIT_WATCH:
 393	case AUDIT_DIR:
 394	case AUDIT_FILTERKEY:
 395	case AUDIT_LOGINUID_SET:
 396	case AUDIT_ARCH:
 397	case AUDIT_FSTYPE:
 398	case AUDIT_PERM:
 399	case AUDIT_FILETYPE:
 400	case AUDIT_FIELD_COMPARE:
 401	case AUDIT_EXE:
 402		/* only equal and not equal valid ops */
 403		if (f->op != Audit_not_equal && f->op != Audit_equal)
 404			return -EINVAL;
 405		break;
 406	default:
 407		/* field not recognized */
 408		return -EINVAL;
 409	}
 410
 411	/* Check for select valid field values */
 412	switch (f->type) {
 413	case AUDIT_LOGINUID_SET:
 414		if ((f->val != 0) && (f->val != 1))
 415			return -EINVAL;
 416		break;
 417	case AUDIT_PERM:
 418		if (f->val & ~15)
 419			return -EINVAL;
 420		break;
 421	case AUDIT_FILETYPE:
 422		if (f->val & ~S_IFMT)
 423			return -EINVAL;
 424		break;
 425	case AUDIT_FIELD_COMPARE:
 426		if (f->val > AUDIT_MAX_FIELD_COMPARE)
 427			return -EINVAL;
 428		break;
 429	case AUDIT_SADDR_FAM:
 430		if (f->val >= AF_MAX)
 431			return -EINVAL;
 432		break;
 433	default:
 434		break;
 435	}
 436
 437	return 0;
 438}
 439
 440/* Translate struct audit_rule_data to kernel's rule representation. */
 441static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
 442					       size_t datasz)
 443{
 444	int err = 0;
 445	struct audit_entry *entry;
 446	void *bufp;
 447	size_t remain = datasz - sizeof(struct audit_rule_data);
 448	int i;
 449	char *str;
 450	struct audit_fsnotify_mark *audit_mark;
 451
 452	entry = audit_to_entry_common(data);
 453	if (IS_ERR(entry))
 454		goto exit_nofree;
 455
 456	bufp = data->buf;
 457	for (i = 0; i < data->field_count; i++) {
 458		struct audit_field *f = &entry->rule.fields[i];
 459		u32 f_val;
 460
 461		err = -EINVAL;
 462
 463		f->op = audit_to_op(data->fieldflags[i]);
 464		if (f->op == Audit_bad)
 465			goto exit_free;
 466
 467		f->type = data->fields[i];
 468		f_val = data->values[i];
 469
 470		/* Support legacy tests for a valid loginuid */
 471		if ((f->type == AUDIT_LOGINUID) && (f_val == AUDIT_UID_UNSET)) {
 472			f->type = AUDIT_LOGINUID_SET;
 473			f_val = 0;
 474			entry->rule.pflags |= AUDIT_LOGINUID_LEGACY;
 475		}
 476
 477		err = audit_field_valid(entry, f);
 478		if (err)
 479			goto exit_free;
 480
 481		err = -EINVAL;
 482		switch (f->type) {
 483		case AUDIT_LOGINUID:
 484		case AUDIT_UID:
 485		case AUDIT_EUID:
 486		case AUDIT_SUID:
 487		case AUDIT_FSUID:
 488		case AUDIT_OBJ_UID:
 489			f->uid = make_kuid(current_user_ns(), f_val);
 490			if (!uid_valid(f->uid))
 491				goto exit_free;
 492			break;
 493		case AUDIT_GID:
 494		case AUDIT_EGID:
 495		case AUDIT_SGID:
 496		case AUDIT_FSGID:
 497		case AUDIT_OBJ_GID:
 498			f->gid = make_kgid(current_user_ns(), f_val);
 499			if (!gid_valid(f->gid))
 500				goto exit_free;
 501			break;
 502		case AUDIT_ARCH:
 503			f->val = f_val;
 504			entry->rule.arch_f = f;
 505			break;
 506		case AUDIT_SUBJ_USER:
 507		case AUDIT_SUBJ_ROLE:
 508		case AUDIT_SUBJ_TYPE:
 509		case AUDIT_SUBJ_SEN:
 510		case AUDIT_SUBJ_CLR:
 511		case AUDIT_OBJ_USER:
 512		case AUDIT_OBJ_ROLE:
 513		case AUDIT_OBJ_TYPE:
 514		case AUDIT_OBJ_LEV_LOW:
 515		case AUDIT_OBJ_LEV_HIGH:
 516			str = audit_unpack_string(&bufp, &remain, f_val);
 517			if (IS_ERR(str)) {
 518				err = PTR_ERR(str);
 519				goto exit_free;
 520			}
 521			entry->rule.buflen += f_val;
 522			f->lsm_str = str;
 523			err = security_audit_rule_init(f->type, f->op, str,
 524						       (void **)&f->lsm_rule);
 525			/* Keep currently invalid fields around in case they
 526			 * become valid after a policy reload. */
 527			if (err == -EINVAL) {
 528				pr_warn("audit rule for LSM \'%s\' is invalid\n",
 529					str);
 530				err = 0;
 531			} else if (err)
 532				goto exit_free;
 533			break;
 534		case AUDIT_WATCH:
 535			str = audit_unpack_string(&bufp, &remain, f_val);
 536			if (IS_ERR(str)) {
 537				err = PTR_ERR(str);
 538				goto exit_free;
 539			}
 540			err = audit_to_watch(&entry->rule, str, f_val, f->op);
 541			if (err) {
 542				kfree(str);
 543				goto exit_free;
 544			}
 545			entry->rule.buflen += f_val;
 546			break;
 547		case AUDIT_DIR:
 548			str = audit_unpack_string(&bufp, &remain, f_val);
 549			if (IS_ERR(str)) {
 550				err = PTR_ERR(str);
 551				goto exit_free;
 552			}
 553			err = audit_make_tree(&entry->rule, str, f->op);
 554			kfree(str);
 555			if (err)
 556				goto exit_free;
 557			entry->rule.buflen += f_val;
 558			break;
 559		case AUDIT_INODE:
 560			f->val = f_val;
 561			err = audit_to_inode(&entry->rule, f);
 562			if (err)
 563				goto exit_free;
 564			break;
 565		case AUDIT_FILTERKEY:
 566			if (entry->rule.filterkey || f_val > AUDIT_MAX_KEY_LEN)
 567				goto exit_free;
 568			str = audit_unpack_string(&bufp, &remain, f_val);
 569			if (IS_ERR(str)) {
 570				err = PTR_ERR(str);
 571				goto exit_free;
 572			}
 573			entry->rule.buflen += f_val;
 574			entry->rule.filterkey = str;
 575			break;
 576		case AUDIT_EXE:
 577			if (entry->rule.exe || f_val > PATH_MAX)
 578				goto exit_free;
 579			str = audit_unpack_string(&bufp, &remain, f_val);
 580			if (IS_ERR(str)) {
 581				err = PTR_ERR(str);
 582				goto exit_free;
 583			}
 584			audit_mark = audit_alloc_mark(&entry->rule, str, f_val);
 585			if (IS_ERR(audit_mark)) {
 586				kfree(str);
 587				err = PTR_ERR(audit_mark);
 588				goto exit_free;
 589			}
 590			entry->rule.buflen += f_val;
 591			entry->rule.exe = audit_mark;
 592			break;
 593		default:
 594			f->val = f_val;
 595			break;
 596		}
 597	}
 598
 599	if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal)
 600		entry->rule.inode_f = NULL;
 601
 602exit_nofree:
 603	return entry;
 604
 605exit_free:
 606	if (entry->rule.tree)
 607		audit_put_tree(entry->rule.tree); /* that's the temporary one */
 608	if (entry->rule.exe)
 609		audit_remove_mark(entry->rule.exe); /* that's the template one */
 610	audit_free_rule(entry);
 611	return ERR_PTR(err);
 612}
 613
 614/* Pack a filter field's string representation into data block. */
 615static inline size_t audit_pack_string(void **bufp, const char *str)
 616{
 617	size_t len = strlen(str);
 618
 619	memcpy(*bufp, str, len);
 620	*bufp += len;
 621
 622	return len;
 623}
 624
 625/* Translate kernel rule representation to struct audit_rule_data. */
 626static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule)
 627{
 628	struct audit_rule_data *data;
 629	void *bufp;
 630	int i;
 631
 632	data = kmalloc(sizeof(*data) + krule->buflen, GFP_KERNEL);
 633	if (unlikely(!data))
 634		return NULL;
 635	memset(data, 0, sizeof(*data));
 636
 637	data->flags = krule->flags | krule->listnr;
 638	data->action = krule->action;
 639	data->field_count = krule->field_count;
 640	bufp = data->buf;
 641	for (i = 0; i < data->field_count; i++) {
 642		struct audit_field *f = &krule->fields[i];
 643
 644		data->fields[i] = f->type;
 645		data->fieldflags[i] = audit_ops[f->op];
 646		switch(f->type) {
 647		case AUDIT_SUBJ_USER:
 648		case AUDIT_SUBJ_ROLE:
 649		case AUDIT_SUBJ_TYPE:
 650		case AUDIT_SUBJ_SEN:
 651		case AUDIT_SUBJ_CLR:
 652		case AUDIT_OBJ_USER:
 653		case AUDIT_OBJ_ROLE:
 654		case AUDIT_OBJ_TYPE:
 655		case AUDIT_OBJ_LEV_LOW:
 656		case AUDIT_OBJ_LEV_HIGH:
 657			data->buflen += data->values[i] =
 658				audit_pack_string(&bufp, f->lsm_str);
 659			break;
 660		case AUDIT_WATCH:
 661			data->buflen += data->values[i] =
 662				audit_pack_string(&bufp,
 663						  audit_watch_path(krule->watch));
 664			break;
 665		case AUDIT_DIR:
 666			data->buflen += data->values[i] =
 667				audit_pack_string(&bufp,
 668						  audit_tree_path(krule->tree));
 669			break;
 670		case AUDIT_FILTERKEY:
 671			data->buflen += data->values[i] =
 672				audit_pack_string(&bufp, krule->filterkey);
 673			break;
 674		case AUDIT_EXE:
 675			data->buflen += data->values[i] =
 676				audit_pack_string(&bufp, audit_mark_path(krule->exe));
 677			break;
 678		case AUDIT_LOGINUID_SET:
 679			if (krule->pflags & AUDIT_LOGINUID_LEGACY && !f->val) {
 680				data->fields[i] = AUDIT_LOGINUID;
 681				data->values[i] = AUDIT_UID_UNSET;
 682				break;
 683			}
 684			fallthrough;	/* if set */
 685		default:
 686			data->values[i] = f->val;
 687		}
 688	}
 689	for (i = 0; i < AUDIT_BITMASK_SIZE; i++) data->mask[i] = krule->mask[i];
 690
 691	return data;
 692}
 693
 694/* Compare two rules in kernel format.  Considered success if rules
 695 * don't match. */
 696static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
 697{
 698	int i;
 699
 700	if (a->flags != b->flags ||
 701	    a->pflags != b->pflags ||
 702	    a->listnr != b->listnr ||
 703	    a->action != b->action ||
 704	    a->field_count != b->field_count)
 705		return 1;
 706
 707	for (i = 0; i < a->field_count; i++) {
 708		if (a->fields[i].type != b->fields[i].type ||
 709		    a->fields[i].op != b->fields[i].op)
 710			return 1;
 711
 712		switch(a->fields[i].type) {
 713		case AUDIT_SUBJ_USER:
 714		case AUDIT_SUBJ_ROLE:
 715		case AUDIT_SUBJ_TYPE:
 716		case AUDIT_SUBJ_SEN:
 717		case AUDIT_SUBJ_CLR:
 718		case AUDIT_OBJ_USER:
 719		case AUDIT_OBJ_ROLE:
 720		case AUDIT_OBJ_TYPE:
 721		case AUDIT_OBJ_LEV_LOW:
 722		case AUDIT_OBJ_LEV_HIGH:
 723			if (strcmp(a->fields[i].lsm_str, b->fields[i].lsm_str))
 724				return 1;
 725			break;
 726		case AUDIT_WATCH:
 727			if (strcmp(audit_watch_path(a->watch),
 728				   audit_watch_path(b->watch)))
 729				return 1;
 730			break;
 731		case AUDIT_DIR:
 732			if (strcmp(audit_tree_path(a->tree),
 733				   audit_tree_path(b->tree)))
 734				return 1;
 735			break;
 736		case AUDIT_FILTERKEY:
 737			/* both filterkeys exist based on above type compare */
 738			if (strcmp(a->filterkey, b->filterkey))
 739				return 1;
 740			break;
 741		case AUDIT_EXE:
 742			/* both paths exist based on above type compare */
 743			if (strcmp(audit_mark_path(a->exe),
 744				   audit_mark_path(b->exe)))
 745				return 1;
 746			break;
 747		case AUDIT_UID:
 748		case AUDIT_EUID:
 749		case AUDIT_SUID:
 750		case AUDIT_FSUID:
 751		case AUDIT_LOGINUID:
 752		case AUDIT_OBJ_UID:
 753			if (!uid_eq(a->fields[i].uid, b->fields[i].uid))
 754				return 1;
 755			break;
 756		case AUDIT_GID:
 757		case AUDIT_EGID:
 758		case AUDIT_SGID:
 759		case AUDIT_FSGID:
 760		case AUDIT_OBJ_GID:
 761			if (!gid_eq(a->fields[i].gid, b->fields[i].gid))
 762				return 1;
 763			break;
 764		default:
 765			if (a->fields[i].val != b->fields[i].val)
 766				return 1;
 767		}
 768	}
 769
 770	for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
 771		if (a->mask[i] != b->mask[i])
 772			return 1;
 773
 774	return 0;
 775}
 776
 777/* Duplicate LSM field information.  The lsm_rule is opaque, so must be
 778 * re-initialized. */
 779static inline int audit_dupe_lsm_field(struct audit_field *df,
 780					   struct audit_field *sf)
 781{
 782	int ret = 0;
 783	char *lsm_str;
 784
 785	/* our own copy of lsm_str */
 786	lsm_str = kstrdup(sf->lsm_str, GFP_KERNEL);
 787	if (unlikely(!lsm_str))
 788		return -ENOMEM;
 789	df->lsm_str = lsm_str;
 790
 791	/* our own (refreshed) copy of lsm_rule */
 792	ret = security_audit_rule_init(df->type, df->op, df->lsm_str,
 793				       (void **)&df->lsm_rule);
 794	/* Keep currently invalid fields around in case they
 795	 * become valid after a policy reload. */
 796	if (ret == -EINVAL) {
 797		pr_warn("audit rule for LSM \'%s\' is invalid\n",
 798			df->lsm_str);
 799		ret = 0;
 800	}
 801
 802	return ret;
 803}
 804
 805/* Duplicate an audit rule.  This will be a deep copy with the exception
 806 * of the watch - that pointer is carried over.  The LSM specific fields
 807 * will be updated in the copy.  The point is to be able to replace the old
 808 * rule with the new rule in the filterlist, then free the old rule.
 809 * The rlist element is undefined; list manipulations are handled apart from
 810 * the initial copy. */
 811struct audit_entry *audit_dupe_rule(struct audit_krule *old)
 812{
 813	u32 fcount = old->field_count;
 814	struct audit_entry *entry;
 815	struct audit_krule *new;
 816	char *fk;
 817	int i, err = 0;
 818
 819	entry = audit_init_entry(fcount);
 820	if (unlikely(!entry))
 821		return ERR_PTR(-ENOMEM);
 822
 823	new = &entry->rule;
 824	new->flags = old->flags;
 825	new->pflags = old->pflags;
 826	new->listnr = old->listnr;
 827	new->action = old->action;
 828	for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
 829		new->mask[i] = old->mask[i];
 830	new->prio = old->prio;
 831	new->buflen = old->buflen;
 832	new->inode_f = old->inode_f;
 833	new->field_count = old->field_count;
 834
 835	/*
 836	 * note that we are OK with not refcounting here; audit_match_tree()
 837	 * never dereferences tree and we can't get false positives there
 838	 * since we'd have to have rule gone from the list *and* removed
 839	 * before the chunks found by lookup had been allocated, i.e. before
 840	 * the beginning of list scan.
 841	 */
 842	new->tree = old->tree;
 843	memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount);
 844
 845	/* deep copy this information, updating the lsm_rule fields, because
 846	 * the originals will all be freed when the old rule is freed. */
 847	for (i = 0; i < fcount; i++) {
 848		switch (new->fields[i].type) {
 849		case AUDIT_SUBJ_USER:
 850		case AUDIT_SUBJ_ROLE:
 851		case AUDIT_SUBJ_TYPE:
 852		case AUDIT_SUBJ_SEN:
 853		case AUDIT_SUBJ_CLR:
 854		case AUDIT_OBJ_USER:
 855		case AUDIT_OBJ_ROLE:
 856		case AUDIT_OBJ_TYPE:
 857		case AUDIT_OBJ_LEV_LOW:
 858		case AUDIT_OBJ_LEV_HIGH:
 859			err = audit_dupe_lsm_field(&new->fields[i],
 860						       &old->fields[i]);
 861			break;
 862		case AUDIT_FILTERKEY:
 863			fk = kstrdup(old->filterkey, GFP_KERNEL);
 864			if (unlikely(!fk))
 865				err = -ENOMEM;
 866			else
 867				new->filterkey = fk;
 868			break;
 869		case AUDIT_EXE:
 870			err = audit_dupe_exe(new, old);
 871			break;
 872		}
 873		if (err) {
 874			if (new->exe)
 875				audit_remove_mark(new->exe);
 876			audit_free_rule(entry);
 877			return ERR_PTR(err);
 878		}
 879	}
 880
 881	if (old->watch) {
 882		audit_get_watch(old->watch);
 883		new->watch = old->watch;
 884	}
 885
 886	return entry;
 887}
 888
 889/* Find an existing audit rule.
 890 * Caller must hold audit_filter_mutex to prevent stale rule data. */
 891static struct audit_entry *audit_find_rule(struct audit_entry *entry,
 892					   struct list_head **p)
 893{
 894	struct audit_entry *e, *found = NULL;
 895	struct list_head *list;
 896	int h;
 897
 898	if (entry->rule.inode_f) {
 899		h = audit_hash_ino(entry->rule.inode_f->val);
 900		*p = list = &audit_inode_hash[h];
 901	} else if (entry->rule.watch) {
 902		/* we don't know the inode number, so must walk entire hash */
 903		for (h = 0; h < AUDIT_INODE_BUCKETS; h++) {
 904			list = &audit_inode_hash[h];
 905			list_for_each_entry(e, list, list)
 906				if (!audit_compare_rule(&entry->rule, &e->rule)) {
 907					found = e;
 908					goto out;
 909				}
 910		}
 911		goto out;
 912	} else {
 913		*p = list = &audit_filter_list[entry->rule.listnr];
 914	}
 915
 916	list_for_each_entry(e, list, list)
 917		if (!audit_compare_rule(&entry->rule, &e->rule)) {
 918			found = e;
 919			goto out;
 920		}
 921
 922out:
 923	return found;
 924}
 925
 926static u64 prio_low = ~0ULL/2;
 927static u64 prio_high = ~0ULL/2 - 1;
 928
 929/* Add rule to given filterlist if not a duplicate. */
 930static inline int audit_add_rule(struct audit_entry *entry)
 931{
 932	struct audit_entry *e;
 933	struct audit_watch *watch = entry->rule.watch;
 934	struct audit_tree *tree = entry->rule.tree;
 935	struct list_head *list;
 936	int err = 0;
 937#ifdef CONFIG_AUDITSYSCALL
 938	int dont_count = 0;
 939
 940	/* If any of these, don't count towards total */
 941	switch(entry->rule.listnr) {
 942	case AUDIT_FILTER_USER:
 943	case AUDIT_FILTER_EXCLUDE:
 944	case AUDIT_FILTER_FS:
 945		dont_count = 1;
 946	}
 947#endif
 948
 949	mutex_lock(&audit_filter_mutex);
 950	e = audit_find_rule(entry, &list);
 951	if (e) {
 952		mutex_unlock(&audit_filter_mutex);
 953		err = -EEXIST;
 954		/* normally audit_add_tree_rule() will free it on failure */
 955		if (tree)
 956			audit_put_tree(tree);
 957		return err;
 958	}
 959
 960	if (watch) {
 961		/* audit_filter_mutex is dropped and re-taken during this call */
 962		err = audit_add_watch(&entry->rule, &list);
 963		if (err) {
 964			mutex_unlock(&audit_filter_mutex);
 965			/*
 966			 * normally audit_add_tree_rule() will free it
 967			 * on failure
 968			 */
 969			if (tree)
 970				audit_put_tree(tree);
 971			return err;
 972		}
 973	}
 974	if (tree) {
 975		err = audit_add_tree_rule(&entry->rule);
 976		if (err) {
 977			mutex_unlock(&audit_filter_mutex);
 978			return err;
 979		}
 980	}
 981
 982	entry->rule.prio = ~0ULL;
 983	if (entry->rule.listnr == AUDIT_FILTER_EXIT) {
 
 984		if (entry->rule.flags & AUDIT_FILTER_PREPEND)
 985			entry->rule.prio = ++prio_high;
 986		else
 987			entry->rule.prio = --prio_low;
 988	}
 989
 990	if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
 991		list_add(&entry->rule.list,
 992			 &audit_rules_list[entry->rule.listnr]);
 993		list_add_rcu(&entry->list, list);
 994		entry->rule.flags &= ~AUDIT_FILTER_PREPEND;
 995	} else {
 996		list_add_tail(&entry->rule.list,
 997			      &audit_rules_list[entry->rule.listnr]);
 998		list_add_tail_rcu(&entry->list, list);
 999	}
1000#ifdef CONFIG_AUDITSYSCALL
1001	if (!dont_count)
1002		audit_n_rules++;
1003
1004	if (!audit_match_signal(entry))
1005		audit_signals++;
1006#endif
1007	mutex_unlock(&audit_filter_mutex);
1008
1009	return err;
1010}
1011
1012/* Remove an existing rule from filterlist. */
1013int audit_del_rule(struct audit_entry *entry)
1014{
1015	struct audit_entry  *e;
1016	struct audit_tree *tree = entry->rule.tree;
1017	struct list_head *list;
1018	int ret = 0;
1019#ifdef CONFIG_AUDITSYSCALL
1020	int dont_count = 0;
1021
1022	/* If any of these, don't count towards total */
1023	switch(entry->rule.listnr) {
1024	case AUDIT_FILTER_USER:
1025	case AUDIT_FILTER_EXCLUDE:
1026	case AUDIT_FILTER_FS:
1027		dont_count = 1;
1028	}
1029#endif
1030
1031	mutex_lock(&audit_filter_mutex);
1032	e = audit_find_rule(entry, &list);
1033	if (!e) {
1034		ret = -ENOENT;
1035		goto out;
1036	}
1037
1038	if (e->rule.watch)
1039		audit_remove_watch_rule(&e->rule);
1040
1041	if (e->rule.tree)
1042		audit_remove_tree_rule(&e->rule);
1043
1044	if (e->rule.exe)
1045		audit_remove_mark_rule(&e->rule);
1046
1047#ifdef CONFIG_AUDITSYSCALL
1048	if (!dont_count)
1049		audit_n_rules--;
1050
1051	if (!audit_match_signal(entry))
1052		audit_signals--;
1053#endif
1054
1055	list_del_rcu(&e->list);
1056	list_del(&e->rule.list);
1057	call_rcu(&e->rcu, audit_free_rule_rcu);
1058
1059out:
1060	mutex_unlock(&audit_filter_mutex);
1061
1062	if (tree)
1063		audit_put_tree(tree);	/* that's the temporary one */
1064
1065	return ret;
1066}
1067
1068/* List rules using struct audit_rule_data. */
1069static void audit_list_rules(int seq, struct sk_buff_head *q)
1070{
1071	struct sk_buff *skb;
1072	struct audit_krule *r;
1073	int i;
1074
1075	/* This is a blocking read, so use audit_filter_mutex instead of rcu
1076	 * iterator to sync with list writers. */
1077	for (i=0; i<AUDIT_NR_FILTERS; i++) {
1078		list_for_each_entry(r, &audit_rules_list[i], list) {
1079			struct audit_rule_data *data;
1080
1081			data = audit_krule_to_data(r);
1082			if (unlikely(!data))
1083				break;
1084			skb = audit_make_reply(seq, AUDIT_LIST_RULES, 0, 1,
1085					       data,
1086					       sizeof(*data) + data->buflen);
1087			if (skb)
1088				skb_queue_tail(q, skb);
1089			kfree(data);
1090		}
1091	}
1092	skb = audit_make_reply(seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);
1093	if (skb)
1094		skb_queue_tail(q, skb);
1095}
1096
1097/* Log rule additions and removals */
1098static void audit_log_rule_change(char *action, struct audit_krule *rule, int res)
1099{
1100	struct audit_buffer *ab;
1101
1102	if (!audit_enabled)
1103		return;
1104
1105	ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_CONFIG_CHANGE);
1106	if (!ab)
1107		return;
1108	audit_log_session_info(ab);
1109	audit_log_task_context(ab);
1110	audit_log_format(ab, " op=%s", action);
1111	audit_log_key(ab, rule->filterkey);
1112	audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
1113	audit_log_end(ab);
1114}
1115
1116/**
1117 * audit_rule_change - apply all rules to the specified message type
1118 * @type: audit message type
1119 * @seq: netlink audit message sequence (serial) number
1120 * @data: payload data
1121 * @datasz: size of payload data
1122 */
1123int audit_rule_change(int type, int seq, void *data, size_t datasz)
1124{
1125	int err = 0;
1126	struct audit_entry *entry;
1127
1128	switch (type) {
1129	case AUDIT_ADD_RULE:
1130		entry = audit_data_to_entry(data, datasz);
1131		if (IS_ERR(entry))
1132			return PTR_ERR(entry);
1133		err = audit_add_rule(entry);
1134		audit_log_rule_change("add_rule", &entry->rule, !err);
1135		break;
1136	case AUDIT_DEL_RULE:
1137		entry = audit_data_to_entry(data, datasz);
1138		if (IS_ERR(entry))
1139			return PTR_ERR(entry);
1140		err = audit_del_rule(entry);
1141		audit_log_rule_change("remove_rule", &entry->rule, !err);
1142		break;
1143	default:
1144		WARN_ON(1);
1145		return -EINVAL;
1146	}
1147
1148	if (err || type == AUDIT_DEL_RULE) {
1149		if (entry->rule.exe)
1150			audit_remove_mark(entry->rule.exe);
1151		audit_free_rule(entry);
1152	}
1153
1154	return err;
1155}
1156
1157/**
1158 * audit_list_rules_send - list the audit rules
1159 * @request_skb: skb of request we are replying to (used to target the reply)
1160 * @seq: netlink audit message sequence (serial) number
1161 */
1162int audit_list_rules_send(struct sk_buff *request_skb, int seq)
1163{
1164	struct task_struct *tsk;
1165	struct audit_netlink_list *dest;
1166
1167	/* We can't just spew out the rules here because we might fill
1168	 * the available socket buffer space and deadlock waiting for
1169	 * auditctl to read from it... which isn't ever going to
1170	 * happen if we're actually running in the context of auditctl
1171	 * trying to _send_ the stuff */
1172
1173	dest = kmalloc(sizeof(*dest), GFP_KERNEL);
1174	if (!dest)
1175		return -ENOMEM;
1176	dest->net = get_net(sock_net(NETLINK_CB(request_skb).sk));
1177	dest->portid = NETLINK_CB(request_skb).portid;
1178	skb_queue_head_init(&dest->q);
1179
1180	mutex_lock(&audit_filter_mutex);
1181	audit_list_rules(seq, &dest->q);
1182	mutex_unlock(&audit_filter_mutex);
1183
1184	tsk = kthread_run(audit_send_list_thread, dest, "audit_send_list");
1185	if (IS_ERR(tsk)) {
1186		skb_queue_purge(&dest->q);
1187		put_net(dest->net);
1188		kfree(dest);
1189		return PTR_ERR(tsk);
1190	}
1191
1192	return 0;
1193}
1194
1195int audit_comparator(u32 left, u32 op, u32 right)
1196{
1197	switch (op) {
1198	case Audit_equal:
1199		return (left == right);
1200	case Audit_not_equal:
1201		return (left != right);
1202	case Audit_lt:
1203		return (left < right);
1204	case Audit_le:
1205		return (left <= right);
1206	case Audit_gt:
1207		return (left > right);
1208	case Audit_ge:
1209		return (left >= right);
1210	case Audit_bitmask:
1211		return (left & right);
1212	case Audit_bittest:
1213		return ((left & right) == right);
1214	default:
1215		return 0;
1216	}
1217}
1218
1219int audit_uid_comparator(kuid_t left, u32 op, kuid_t right)
1220{
1221	switch (op) {
1222	case Audit_equal:
1223		return uid_eq(left, right);
1224	case Audit_not_equal:
1225		return !uid_eq(left, right);
1226	case Audit_lt:
1227		return uid_lt(left, right);
1228	case Audit_le:
1229		return uid_lte(left, right);
1230	case Audit_gt:
1231		return uid_gt(left, right);
1232	case Audit_ge:
1233		return uid_gte(left, right);
1234	case Audit_bitmask:
1235	case Audit_bittest:
1236	default:
1237		return 0;
1238	}
1239}
1240
1241int audit_gid_comparator(kgid_t left, u32 op, kgid_t right)
1242{
1243	switch (op) {
1244	case Audit_equal:
1245		return gid_eq(left, right);
1246	case Audit_not_equal:
1247		return !gid_eq(left, right);
1248	case Audit_lt:
1249		return gid_lt(left, right);
1250	case Audit_le:
1251		return gid_lte(left, right);
1252	case Audit_gt:
1253		return gid_gt(left, right);
1254	case Audit_ge:
1255		return gid_gte(left, right);
1256	case Audit_bitmask:
1257	case Audit_bittest:
1258	default:
1259		return 0;
1260	}
1261}
1262
1263/**
1264 * parent_len - find the length of the parent portion of a pathname
1265 * @path: pathname of which to determine length
1266 */
1267int parent_len(const char *path)
1268{
1269	int plen;
1270	const char *p;
1271
1272	plen = strlen(path);
1273
1274	if (plen == 0)
1275		return plen;
1276
1277	/* disregard trailing slashes */
1278	p = path + plen - 1;
1279	while ((*p == '/') && (p > path))
1280		p--;
1281
1282	/* walk backward until we find the next slash or hit beginning */
1283	while ((*p != '/') && (p > path))
1284		p--;
1285
1286	/* did we find a slash? Then increment to include it in path */
1287	if (*p == '/')
1288		p++;
1289
1290	return p - path;
1291}
1292
1293/**
1294 * audit_compare_dname_path - compare given dentry name with last component in
1295 * 			      given path. Return of 0 indicates a match.
1296 * @dname:	dentry name that we're comparing
1297 * @path:	full pathname that we're comparing
1298 * @parentlen:	length of the parent if known. Passing in AUDIT_NAME_FULL
1299 * 		here indicates that we must compute this value.
1300 */
1301int audit_compare_dname_path(const struct qstr *dname, const char *path, int parentlen)
1302{
1303	int dlen, pathlen;
1304	const char *p;
1305
1306	dlen = dname->len;
1307	pathlen = strlen(path);
1308	if (pathlen < dlen)
1309		return 1;
1310
1311	parentlen = parentlen == AUDIT_NAME_FULL ? parent_len(path) : parentlen;
1312	if (pathlen - parentlen != dlen)
1313		return 1;
1314
1315	p = path + parentlen;
1316
1317	return strncmp(p, dname->name, dlen);
1318}
1319
1320int audit_filter(int msgtype, unsigned int listtype)
1321{
1322	struct audit_entry *e;
1323	int ret = 1; /* Audit by default */
1324
1325	rcu_read_lock();
1326	list_for_each_entry_rcu(e, &audit_filter_list[listtype], list) {
1327		int i, result = 0;
1328
1329		for (i = 0; i < e->rule.field_count; i++) {
1330			struct audit_field *f = &e->rule.fields[i];
1331			pid_t pid;
1332			u32 sid;
1333
1334			switch (f->type) {
1335			case AUDIT_PID:
1336				pid = task_pid_nr(current);
1337				result = audit_comparator(pid, f->op, f->val);
1338				break;
1339			case AUDIT_UID:
1340				result = audit_uid_comparator(current_uid(), f->op, f->uid);
1341				break;
1342			case AUDIT_GID:
1343				result = audit_gid_comparator(current_gid(), f->op, f->gid);
1344				break;
1345			case AUDIT_LOGINUID:
1346				result = audit_uid_comparator(audit_get_loginuid(current),
1347							      f->op, f->uid);
1348				break;
1349			case AUDIT_LOGINUID_SET:
1350				result = audit_comparator(audit_loginuid_set(current),
1351							  f->op, f->val);
1352				break;
1353			case AUDIT_MSGTYPE:
1354				result = audit_comparator(msgtype, f->op, f->val);
1355				break;
1356			case AUDIT_SUBJ_USER:
1357			case AUDIT_SUBJ_ROLE:
1358			case AUDIT_SUBJ_TYPE:
1359			case AUDIT_SUBJ_SEN:
1360			case AUDIT_SUBJ_CLR:
1361				if (f->lsm_rule) {
1362					security_task_getsecid(current, &sid);
1363					result = security_audit_rule_match(sid,
1364						   f->type, f->op, f->lsm_rule);
1365				}
1366				break;
1367			case AUDIT_EXE:
1368				result = audit_exe_compare(current, e->rule.exe);
1369				if (f->op == Audit_not_equal)
1370					result = !result;
1371				break;
1372			default:
1373				goto unlock_and_return;
1374			}
1375			if (result < 0) /* error */
1376				goto unlock_and_return;
1377			if (!result)
1378				break;
1379		}
1380		if (result > 0) {
1381			if (e->rule.action == AUDIT_NEVER || listtype == AUDIT_FILTER_EXCLUDE)
1382				ret = 0;
1383			break;
1384		}
1385	}
1386unlock_and_return:
1387	rcu_read_unlock();
1388	return ret;
1389}
1390
1391static int update_lsm_rule(struct audit_krule *r)
1392{
1393	struct audit_entry *entry = container_of(r, struct audit_entry, rule);
1394	struct audit_entry *nentry;
1395	int err = 0;
1396
1397	if (!security_audit_rule_known(r))
1398		return 0;
1399
1400	nentry = audit_dupe_rule(r);
1401	if (entry->rule.exe)
1402		audit_remove_mark(entry->rule.exe);
1403	if (IS_ERR(nentry)) {
1404		/* save the first error encountered for the
1405		 * return value */
1406		err = PTR_ERR(nentry);
1407		audit_panic("error updating LSM filters");
1408		if (r->watch)
1409			list_del(&r->rlist);
1410		list_del_rcu(&entry->list);
1411		list_del(&r->list);
1412	} else {
1413		if (r->watch || r->tree)
1414			list_replace_init(&r->rlist, &nentry->rule.rlist);
1415		list_replace_rcu(&entry->list, &nentry->list);
1416		list_replace(&r->list, &nentry->rule.list);
1417	}
1418	call_rcu(&entry->rcu, audit_free_rule_rcu);
1419
1420	return err;
1421}
1422
1423/* This function will re-initialize the lsm_rule field of all applicable rules.
1424 * It will traverse the filter lists serarching for rules that contain LSM
1425 * specific filter fields.  When such a rule is found, it is copied, the
1426 * LSM field is re-initialized, and the old rule is replaced with the
1427 * updated rule. */
1428int audit_update_lsm_rules(void)
1429{
1430	struct audit_krule *r, *n;
1431	int i, err = 0;
1432
1433	/* audit_filter_mutex synchronizes the writers */
1434	mutex_lock(&audit_filter_mutex);
1435
1436	for (i = 0; i < AUDIT_NR_FILTERS; i++) {
1437		list_for_each_entry_safe(r, n, &audit_rules_list[i], list) {
1438			int res = update_lsm_rule(r);
1439			if (!err)
1440				err = res;
1441		}
1442	}
1443	mutex_unlock(&audit_filter_mutex);
1444
1445	return err;
1446}