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auditfilter.c
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1 /* auditfilter.c -- filtering of audit events
2  *
3  * Copyright 2003-2004 Red Hat, Inc.
4  * Copyright 2005 Hewlett-Packard Development Company, L.P.
5  * Copyright 2005 IBM Corporation
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License as published by
9  * the Free Software Foundation; either version 2 of the License, or
10  * (at your option) any later version.
11  *
12  * This program is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15  * GNU General Public License for more details.
16  *
17  * You should have received a copy of the GNU General Public License
18  * along with this program; if not, write to the Free Software
19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20  */
21 
22 #include <linux/kernel.h>
23 #include <linux/audit.h>
24 #include <linux/kthread.h>
25 #include <linux/mutex.h>
26 #include <linux/fs.h>
27 #include <linux/namei.h>
28 #include <linux/netlink.h>
29 #include <linux/sched.h>
30 #include <linux/slab.h>
31 #include <linux/security.h>
32 #include "audit.h"
33 
34 /*
35  * Locking model:
36  *
37  * audit_filter_mutex:
38  * Synchronizes writes and blocking reads of audit's filterlist
39  * data. Rcu is used to traverse the filterlist and access
40  * contents of structs audit_entry, audit_watch and opaque
41  * LSM rules during filtering. If modified, these structures
42  * must be copied and replace their counterparts in the filterlist.
43  * An audit_parent struct is not accessed during filtering, so may
44  * be written directly provided audit_filter_mutex is held.
45  */
46 
47 /* Audit filter lists, defined in <linux/audit.h> */
48 struct list_head audit_filter_list[AUDIT_NR_FILTERS] = {
49  LIST_HEAD_INIT(audit_filter_list[0]),
50  LIST_HEAD_INIT(audit_filter_list[1]),
51  LIST_HEAD_INIT(audit_filter_list[2]),
52  LIST_HEAD_INIT(audit_filter_list[3]),
53  LIST_HEAD_INIT(audit_filter_list[4]),
54  LIST_HEAD_INIT(audit_filter_list[5]),
55 #if AUDIT_NR_FILTERS != 6
56 #error Fix audit_filter_list initialiser
57 #endif
58 };
59 static struct list_head audit_rules_list[AUDIT_NR_FILTERS] = {
60  LIST_HEAD_INIT(audit_rules_list[0]),
61  LIST_HEAD_INIT(audit_rules_list[1]),
62  LIST_HEAD_INIT(audit_rules_list[2]),
63  LIST_HEAD_INIT(audit_rules_list[3]),
64  LIST_HEAD_INIT(audit_rules_list[4]),
65  LIST_HEAD_INIT(audit_rules_list[5]),
66 };
67 
68 DEFINE_MUTEX(audit_filter_mutex);
69 
70 static inline void audit_free_rule(struct audit_entry *e)
71 {
72  int i;
73  struct audit_krule *erule = &e->rule;
74 
75  /* some rules don't have associated watches */
76  if (erule->watch)
77  audit_put_watch(erule->watch);
78  if (erule->fields)
79  for (i = 0; i < erule->field_count; i++) {
80  struct audit_field *f = &erule->fields[i];
81  kfree(f->lsm_str);
82  security_audit_rule_free(f->lsm_rule);
83  }
84  kfree(erule->fields);
85  kfree(erule->filterkey);
86  kfree(e);
87 }
88 
89 void audit_free_rule_rcu(struct rcu_head *head)
90 {
91  struct audit_entry *e = container_of(head, struct audit_entry, rcu);
92  audit_free_rule(e);
93 }
94 
95 /* Initialize an audit filterlist entry. */
96 static inline struct audit_entry *audit_init_entry(u32 field_count)
97 {
98  struct audit_entry *entry;
99  struct audit_field *fields;
100 
101  entry = kzalloc(sizeof(*entry), GFP_KERNEL);
102  if (unlikely(!entry))
103  return NULL;
104 
105  fields = kzalloc(sizeof(*fields) * field_count, GFP_KERNEL);
106  if (unlikely(!fields)) {
107  kfree(entry);
108  return NULL;
109  }
110  entry->rule.fields = fields;
111 
112  return entry;
113 }
114 
115 /* Unpack a filter field's string representation from user-space
116  * buffer. */
117 char *audit_unpack_string(void **bufp, size_t *remain, size_t len)
118 {
119  char *str;
120 
121  if (!*bufp || (len == 0) || (len > *remain))
122  return ERR_PTR(-EINVAL);
123 
124  /* Of the currently implemented string fields, PATH_MAX
125  * defines the longest valid length.
126  */
127  if (len > PATH_MAX)
128  return ERR_PTR(-ENAMETOOLONG);
129 
130  str = kmalloc(len + 1, GFP_KERNEL);
131  if (unlikely(!str))
132  return ERR_PTR(-ENOMEM);
133 
134  memcpy(str, *bufp, len);
135  str[len] = 0;
136  *bufp += len;
137  *remain -= len;
138 
139  return str;
140 }
141 
142 /* Translate an inode field to kernel respresentation. */
143 static inline int audit_to_inode(struct audit_krule *krule,
144  struct audit_field *f)
145 {
146  if (krule->listnr != AUDIT_FILTER_EXIT ||
147  krule->watch || krule->inode_f || krule->tree ||
148  (f->op != Audit_equal && f->op != Audit_not_equal))
149  return -EINVAL;
150 
151  krule->inode_f = f;
152  return 0;
153 }
154 
155 static __u32 *classes[AUDIT_SYSCALL_CLASSES];
156 
157 int __init audit_register_class(int class, unsigned *list)
158 {
159  __u32 *p = kzalloc(AUDIT_BITMASK_SIZE * sizeof(__u32), GFP_KERNEL);
160  if (!p)
161  return -ENOMEM;
162  while (*list != ~0U) {
163  unsigned n = *list++;
164  if (n >= AUDIT_BITMASK_SIZE * 32 - AUDIT_SYSCALL_CLASSES) {
165  kfree(p);
166  return -EINVAL;
167  }
168  p[AUDIT_WORD(n)] |= AUDIT_BIT(n);
169  }
170  if (class >= AUDIT_SYSCALL_CLASSES || classes[class]) {
171  kfree(p);
172  return -EINVAL;
173  }
174  classes[class] = p;
175  return 0;
176 }
177 
178 int audit_match_class(int class, unsigned syscall)
179 {
180  if (unlikely(syscall >= AUDIT_BITMASK_SIZE * 32))
181  return 0;
182  if (unlikely(class >= AUDIT_SYSCALL_CLASSES || !classes[class]))
183  return 0;
184  return classes[class][AUDIT_WORD(syscall)] & AUDIT_BIT(syscall);
185 }
186 
187 #ifdef CONFIG_AUDITSYSCALL
188 static inline int audit_match_class_bits(int class, u32 *mask)
189 {
190  int i;
191 
192  if (classes[class]) {
193  for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
194  if (mask[i] & classes[class][i])
195  return 0;
196  }
197  return 1;
198 }
199 
200 static int audit_match_signal(struct audit_entry *entry)
201 {
202  struct audit_field *arch = entry->rule.arch_f;
203 
204  if (!arch) {
205  /* When arch is unspecified, we must check both masks on biarch
206  * as syscall number alone is ambiguous. */
207  return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
208  entry->rule.mask) &&
209  audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
210  entry->rule.mask));
211  }
212 
213  switch(audit_classify_arch(arch->val)) {
214  case 0: /* native */
215  return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
216  entry->rule.mask));
217  case 1: /* 32bit on biarch */
218  return (audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
219  entry->rule.mask));
220  default:
221  return 1;
222  }
223 }
224 #endif
225 
226 /* Common user-space to kernel rule translation. */
227 static inline struct audit_entry *audit_to_entry_common(struct audit_rule *rule)
228 {
229  unsigned listnr;
230  struct audit_entry *entry;
231  int i, err;
232 
233  err = -EINVAL;
234  listnr = rule->flags & ~AUDIT_FILTER_PREPEND;
235  switch(listnr) {
236  default:
237  goto exit_err;
238 #ifdef CONFIG_AUDITSYSCALL
239  case AUDIT_FILTER_ENTRY:
240  if (rule->action == AUDIT_ALWAYS)
241  goto exit_err;
242  case AUDIT_FILTER_EXIT:
243  case AUDIT_FILTER_TASK:
244 #endif
245  case AUDIT_FILTER_USER:
246  case AUDIT_FILTER_TYPE:
247  ;
248  }
249  if (unlikely(rule->action == AUDIT_POSSIBLE)) {
250  printk(KERN_ERR "AUDIT_POSSIBLE is deprecated\n");
251  goto exit_err;
252  }
253  if (rule->action != AUDIT_NEVER && rule->action != AUDIT_ALWAYS)
254  goto exit_err;
255  if (rule->field_count > AUDIT_MAX_FIELDS)
256  goto exit_err;
257 
258  err = -ENOMEM;
259  entry = audit_init_entry(rule->field_count);
260  if (!entry)
261  goto exit_err;
262 
263  entry->rule.flags = rule->flags & AUDIT_FILTER_PREPEND;
264  entry->rule.listnr = listnr;
265  entry->rule.action = rule->action;
266  entry->rule.field_count = rule->field_count;
267 
268  for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
269  entry->rule.mask[i] = rule->mask[i];
270 
271  for (i = 0; i < AUDIT_SYSCALL_CLASSES; i++) {
272  int bit = AUDIT_BITMASK_SIZE * 32 - i - 1;
273  __u32 *p = &entry->rule.mask[AUDIT_WORD(bit)];
274  __u32 *class;
275 
276  if (!(*p & AUDIT_BIT(bit)))
277  continue;
278  *p &= ~AUDIT_BIT(bit);
279  class = classes[i];
280  if (class) {
281  int j;
282  for (j = 0; j < AUDIT_BITMASK_SIZE; j++)
283  entry->rule.mask[j] |= class[j];
284  }
285  }
286 
287  return entry;
288 
289 exit_err:
290  return ERR_PTR(err);
291 }
292 
293 static u32 audit_ops[] =
294 {
295  [Audit_equal] = AUDIT_EQUAL,
296  [Audit_not_equal] = AUDIT_NOT_EQUAL,
297  [Audit_bitmask] = AUDIT_BIT_MASK,
298  [Audit_bittest] = AUDIT_BIT_TEST,
299  [Audit_lt] = AUDIT_LESS_THAN,
300  [Audit_gt] = AUDIT_GREATER_THAN,
301  [Audit_le] = AUDIT_LESS_THAN_OR_EQUAL,
302  [Audit_ge] = AUDIT_GREATER_THAN_OR_EQUAL,
303 };
304 
305 static u32 audit_to_op(u32 op)
306 {
307  u32 n;
308  for (n = Audit_equal; n < Audit_bad && audit_ops[n] != op; n++)
309  ;
310  return n;
311 }
312 
313 
314 /* Translate struct audit_rule to kernel's rule respresentation.
315  * Exists for backward compatibility with userspace. */
316 static struct audit_entry *audit_rule_to_entry(struct audit_rule *rule)
317 {
318  struct audit_entry *entry;
319  int err = 0;
320  int i;
321 
322  entry = audit_to_entry_common(rule);
323  if (IS_ERR(entry))
324  goto exit_nofree;
325 
326  for (i = 0; i < rule->field_count; i++) {
327  struct audit_field *f = &entry->rule.fields[i];
328  u32 n;
329 
330  n = rule->fields[i] & (AUDIT_NEGATE|AUDIT_OPERATORS);
331 
332  /* Support for legacy operators where
333  * AUDIT_NEGATE bit signifies != and otherwise assumes == */
334  if (n & AUDIT_NEGATE)
335  f->op = Audit_not_equal;
336  else if (!n)
337  f->op = Audit_equal;
338  else
339  f->op = audit_to_op(n);
340 
341  entry->rule.vers_ops = (n & AUDIT_OPERATORS) ? 2 : 1;
342 
343  f->type = rule->fields[i] & ~(AUDIT_NEGATE|AUDIT_OPERATORS);
344  f->val = rule->values[i];
345  f->uid = INVALID_UID;
346  f->gid = INVALID_GID;
347 
348  err = -EINVAL;
349  if (f->op == Audit_bad)
350  goto exit_free;
351 
352  switch(f->type) {
353  default:
354  goto exit_free;
355  case AUDIT_UID:
356  case AUDIT_EUID:
357  case AUDIT_SUID:
358  case AUDIT_FSUID:
359  case AUDIT_LOGINUID:
360  /* bit ops not implemented for uid comparisons */
361  if (f->op == Audit_bitmask || f->op == Audit_bittest)
362  goto exit_free;
363 
364  f->uid = make_kuid(current_user_ns(), f->val);
365  if (!uid_valid(f->uid))
366  goto exit_free;
367  break;
368  case AUDIT_GID:
369  case AUDIT_EGID:
370  case AUDIT_SGID:
371  case AUDIT_FSGID:
372  /* bit ops not implemented for gid comparisons */
373  if (f->op == Audit_bitmask || f->op == Audit_bittest)
374  goto exit_free;
375 
376  f->gid = make_kgid(current_user_ns(), f->val);
377  if (!gid_valid(f->gid))
378  goto exit_free;
379  break;
380  case AUDIT_PID:
381  case AUDIT_PERS:
382  case AUDIT_MSGTYPE:
383  case AUDIT_PPID:
384  case AUDIT_DEVMAJOR:
385  case AUDIT_DEVMINOR:
386  case AUDIT_EXIT:
387  case AUDIT_SUCCESS:
388  /* bit ops are only useful on syscall args */
389  if (f->op == Audit_bitmask || f->op == Audit_bittest)
390  goto exit_free;
391  break;
392  case AUDIT_ARG0:
393  case AUDIT_ARG1:
394  case AUDIT_ARG2:
395  case AUDIT_ARG3:
396  break;
397  /* arch is only allowed to be = or != */
398  case AUDIT_ARCH:
399  if (f->op != Audit_not_equal && f->op != Audit_equal)
400  goto exit_free;
401  entry->rule.arch_f = f;
402  break;
403  case AUDIT_PERM:
404  if (f->val & ~15)
405  goto exit_free;
406  break;
407  case AUDIT_FILETYPE:
408  if (f->val & ~S_IFMT)
409  goto exit_free;
410  break;
411  case AUDIT_INODE:
412  err = audit_to_inode(&entry->rule, f);
413  if (err)
414  goto exit_free;
415  break;
416  }
417  }
418 
419  if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal)
420  entry->rule.inode_f = NULL;
421 
422 exit_nofree:
423  return entry;
424 
425 exit_free:
426  audit_free_rule(entry);
427  return ERR_PTR(err);
428 }
429 
430 /* Translate struct audit_rule_data to kernel's rule respresentation. */
431 static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
432  size_t datasz)
433 {
434  int err = 0;
435  struct audit_entry *entry;
436  void *bufp;
437  size_t remain = datasz - sizeof(struct audit_rule_data);
438  int i;
439  char *str;
440 
441  entry = audit_to_entry_common((struct audit_rule *)data);
442  if (IS_ERR(entry))
443  goto exit_nofree;
444 
445  bufp = data->buf;
446  entry->rule.vers_ops = 2;
447  for (i = 0; i < data->field_count; i++) {
448  struct audit_field *f = &entry->rule.fields[i];
449 
450  err = -EINVAL;
451 
452  f->op = audit_to_op(data->fieldflags[i]);
453  if (f->op == Audit_bad)
454  goto exit_free;
455 
456  f->type = data->fields[i];
457  f->val = data->values[i];
458  f->uid = INVALID_UID;
459  f->gid = INVALID_GID;
460  f->lsm_str = NULL;
461  f->lsm_rule = NULL;
462  switch(f->type) {
463  case AUDIT_UID:
464  case AUDIT_EUID:
465  case AUDIT_SUID:
466  case AUDIT_FSUID:
467  case AUDIT_LOGINUID:
468  case AUDIT_OBJ_UID:
469  /* bit ops not implemented for uid comparisons */
470  if (f->op == Audit_bitmask || f->op == Audit_bittest)
471  goto exit_free;
472 
473  f->uid = make_kuid(current_user_ns(), f->val);
474  if (!uid_valid(f->uid))
475  goto exit_free;
476  break;
477  case AUDIT_GID:
478  case AUDIT_EGID:
479  case AUDIT_SGID:
480  case AUDIT_FSGID:
481  case AUDIT_OBJ_GID:
482  /* bit ops not implemented for gid comparisons */
483  if (f->op == Audit_bitmask || f->op == Audit_bittest)
484  goto exit_free;
485 
486  f->gid = make_kgid(current_user_ns(), f->val);
487  if (!gid_valid(f->gid))
488  goto exit_free;
489  break;
490  case AUDIT_PID:
491  case AUDIT_PERS:
492  case AUDIT_MSGTYPE:
493  case AUDIT_PPID:
494  case AUDIT_DEVMAJOR:
495  case AUDIT_DEVMINOR:
496  case AUDIT_EXIT:
497  case AUDIT_SUCCESS:
498  case AUDIT_ARG0:
499  case AUDIT_ARG1:
500  case AUDIT_ARG2:
501  case AUDIT_ARG3:
502  break;
503  case AUDIT_ARCH:
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  goto exit_free;
519  entry->rule.buflen += f->val;
520 
521  err = security_audit_rule_init(f->type, f->op, str,
522  (void **)&f->lsm_rule);
523  /* Keep currently invalid fields around in case they
524  * become valid after a policy reload. */
525  if (err == -EINVAL) {
526  printk(KERN_WARNING "audit rule for LSM "
527  "\'%s\' is invalid\n", str);
528  err = 0;
529  }
530  if (err) {
531  kfree(str);
532  goto exit_free;
533  } else
534  f->lsm_str = str;
535  break;
536  case AUDIT_WATCH:
537  str = audit_unpack_string(&bufp, &remain, f->val);
538  if (IS_ERR(str))
539  goto exit_free;
540  entry->rule.buflen += f->val;
541 
542  err = audit_to_watch(&entry->rule, str, f->val, f->op);
543  if (err) {
544  kfree(str);
545  goto exit_free;
546  }
547  break;
548  case AUDIT_DIR:
549  str = audit_unpack_string(&bufp, &remain, f->val);
550  if (IS_ERR(str))
551  goto exit_free;
552  entry->rule.buflen += f->val;
553 
554  err = audit_make_tree(&entry->rule, str, f->op);
555  kfree(str);
556  if (err)
557  goto exit_free;
558  break;
559  case AUDIT_INODE:
560  err = audit_to_inode(&entry->rule, f);
561  if (err)
562  goto exit_free;
563  break;
564  case AUDIT_FILTERKEY:
565  if (entry->rule.filterkey || f->val > AUDIT_MAX_KEY_LEN)
566  goto exit_free;
567  str = audit_unpack_string(&bufp, &remain, f->val);
568  if (IS_ERR(str))
569  goto exit_free;
570  entry->rule.buflen += f->val;
571  entry->rule.filterkey = str;
572  break;
573  case AUDIT_PERM:
574  if (f->val & ~15)
575  goto exit_free;
576  break;
577  case AUDIT_FILETYPE:
578  if (f->val & ~S_IFMT)
579  goto exit_free;
580  break;
581  case AUDIT_FIELD_COMPARE:
582  if (f->val > AUDIT_MAX_FIELD_COMPARE)
583  goto exit_free;
584  break;
585  default:
586  goto exit_free;
587  }
588  }
589 
590  if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal)
591  entry->rule.inode_f = NULL;
592 
593 exit_nofree:
594  return entry;
595 
596 exit_free:
597  audit_free_rule(entry);
598  return ERR_PTR(err);
599 }
600 
601 /* Pack a filter field's string representation into data block. */
602 static inline size_t audit_pack_string(void **bufp, const char *str)
603 {
604  size_t len = strlen(str);
605 
606  memcpy(*bufp, str, len);
607  *bufp += len;
608 
609  return len;
610 }
611 
612 /* Translate kernel rule respresentation to struct audit_rule.
613  * Exists for backward compatibility with userspace. */
614 static struct audit_rule *audit_krule_to_rule(struct audit_krule *krule)
615 {
616  struct audit_rule *rule;
617  int i;
618 
619  rule = kzalloc(sizeof(*rule), GFP_KERNEL);
620  if (unlikely(!rule))
621  return NULL;
622 
623  rule->flags = krule->flags | krule->listnr;
624  rule->action = krule->action;
625  rule->field_count = krule->field_count;
626  for (i = 0; i < rule->field_count; i++) {
627  rule->values[i] = krule->fields[i].val;
628  rule->fields[i] = krule->fields[i].type;
629 
630  if (krule->vers_ops == 1) {
631  if (krule->fields[i].op == Audit_not_equal)
632  rule->fields[i] |= AUDIT_NEGATE;
633  } else {
634  rule->fields[i] |= audit_ops[krule->fields[i].op];
635  }
636  }
637  for (i = 0; i < AUDIT_BITMASK_SIZE; i++) rule->mask[i] = krule->mask[i];
638 
639  return rule;
640 }
641 
642 /* Translate kernel rule respresentation to struct audit_rule_data. */
643 static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule)
644 {
645  struct audit_rule_data *data;
646  void *bufp;
647  int i;
648 
649  data = kmalloc(sizeof(*data) + krule->buflen, GFP_KERNEL);
650  if (unlikely(!data))
651  return NULL;
652  memset(data, 0, sizeof(*data));
653 
654  data->flags = krule->flags | krule->listnr;
655  data->action = krule->action;
656  data->field_count = krule->field_count;
657  bufp = data->buf;
658  for (i = 0; i < data->field_count; i++) {
659  struct audit_field *f = &krule->fields[i];
660 
661  data->fields[i] = f->type;
662  data->fieldflags[i] = audit_ops[f->op];
663  switch(f->type) {
664  case AUDIT_SUBJ_USER:
665  case AUDIT_SUBJ_ROLE:
666  case AUDIT_SUBJ_TYPE:
667  case AUDIT_SUBJ_SEN:
668  case AUDIT_SUBJ_CLR:
669  case AUDIT_OBJ_USER:
670  case AUDIT_OBJ_ROLE:
671  case AUDIT_OBJ_TYPE:
672  case AUDIT_OBJ_LEV_LOW:
673  case AUDIT_OBJ_LEV_HIGH:
674  data->buflen += data->values[i] =
675  audit_pack_string(&bufp, f->lsm_str);
676  break;
677  case AUDIT_WATCH:
678  data->buflen += data->values[i] =
679  audit_pack_string(&bufp,
680  audit_watch_path(krule->watch));
681  break;
682  case AUDIT_DIR:
683  data->buflen += data->values[i] =
684  audit_pack_string(&bufp,
685  audit_tree_path(krule->tree));
686  break;
687  case AUDIT_FILTERKEY:
688  data->buflen += data->values[i] =
689  audit_pack_string(&bufp, krule->filterkey);
690  break;
691  default:
692  data->values[i] = f->val;
693  }
694  }
695  for (i = 0; i < AUDIT_BITMASK_SIZE; i++) data->mask[i] = krule->mask[i];
696 
697  return data;
698 }
699 
700 /* Compare two rules in kernel format. Considered success if rules
701  * don't match. */
702 static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
703 {
704  int i;
705 
706  if (a->flags != b->flags ||
707  a->listnr != b->listnr ||
708  a->action != b->action ||
709  a->field_count != b->field_count)
710  return 1;
711 
712  for (i = 0; i < a->field_count; i++) {
713  if (a->fields[i].type != b->fields[i].type ||
714  a->fields[i].op != b->fields[i].op)
715  return 1;
716 
717  switch(a->fields[i].type) {
718  case AUDIT_SUBJ_USER:
719  case AUDIT_SUBJ_ROLE:
720  case AUDIT_SUBJ_TYPE:
721  case AUDIT_SUBJ_SEN:
722  case AUDIT_SUBJ_CLR:
723  case AUDIT_OBJ_USER:
724  case AUDIT_OBJ_ROLE:
725  case AUDIT_OBJ_TYPE:
726  case AUDIT_OBJ_LEV_LOW:
727  case AUDIT_OBJ_LEV_HIGH:
728  if (strcmp(a->fields[i].lsm_str, b->fields[i].lsm_str))
729  return 1;
730  break;
731  case AUDIT_WATCH:
732  if (strcmp(audit_watch_path(a->watch),
733  audit_watch_path(b->watch)))
734  return 1;
735  break;
736  case AUDIT_DIR:
737  if (strcmp(audit_tree_path(a->tree),
738  audit_tree_path(b->tree)))
739  return 1;
740  break;
741  case AUDIT_FILTERKEY:
742  /* both filterkeys exist based on above type compare */
743  if (strcmp(a->filterkey, b->filterkey))
744  return 1;
745  break;
746  case AUDIT_UID:
747  case AUDIT_EUID:
748  case AUDIT_SUID:
749  case AUDIT_FSUID:
750  case AUDIT_LOGINUID:
751  case AUDIT_OBJ_UID:
752  if (!uid_eq(a->fields[i].uid, b->fields[i].uid))
753  return 1;
754  break;
755  case AUDIT_GID:
756  case AUDIT_EGID:
757  case AUDIT_SGID:
758  case AUDIT_FSGID:
759  case AUDIT_OBJ_GID:
760  if (!gid_eq(a->fields[i].gid, b->fields[i].gid))
761  return 1;
762  break;
763  default:
764  if (a->fields[i].val != b->fields[i].val)
765  return 1;
766  }
767  }
768 
769  for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
770  if (a->mask[i] != b->mask[i])
771  return 1;
772 
773  return 0;
774 }
775 
776 /* Duplicate LSM field information. The lsm_rule is opaque, so must be
777  * re-initialized. */
778 static inline int audit_dupe_lsm_field(struct audit_field *df,
779  struct audit_field *sf)
780 {
781  int ret = 0;
782  char *lsm_str;
783 
784  /* our own copy of lsm_str */
785  lsm_str = kstrdup(sf->lsm_str, GFP_KERNEL);
786  if (unlikely(!lsm_str))
787  return -ENOMEM;
788  df->lsm_str = lsm_str;
789 
790  /* our own (refreshed) copy of lsm_rule */
791  ret = security_audit_rule_init(df->type, df->op, df->lsm_str,
792  (void **)&df->lsm_rule);
793  /* Keep currently invalid fields around in case they
794  * become valid after a policy reload. */
795  if (ret == -EINVAL) {
796  printk(KERN_WARNING "audit rule for LSM \'%s\' is "
797  "invalid\n", df->lsm_str);
798  ret = 0;
799  }
800 
801  return ret;
802 }
803 
804 /* Duplicate an audit rule. This will be a deep copy with the exception
805  * of the watch - that pointer is carried over. The LSM specific fields
806  * will be updated in the copy. The point is to be able to replace the old
807  * rule with the new rule in the filterlist, then free the old rule.
808  * The rlist element is undefined; list manipulations are handled apart from
809  * the initial copy. */
810 struct audit_entry *audit_dupe_rule(struct audit_krule *old)
811 {
812  u32 fcount = old->field_count;
813  struct audit_entry *entry;
814  struct audit_krule *new;
815  char *fk;
816  int i, err = 0;
817 
818  entry = audit_init_entry(fcount);
819  if (unlikely(!entry))
820  return ERR_PTR(-ENOMEM);
821 
822  new = &entry->rule;
823  new->vers_ops = old->vers_ops;
824  new->flags = old->flags;
825  new->listnr = old->listnr;
826  new->action = old->action;
827  for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
828  new->mask[i] = old->mask[i];
829  new->prio = old->prio;
830  new->buflen = old->buflen;
831  new->inode_f = old->inode_f;
832  new->field_count = old->field_count;
833 
834  /*
835  * note that we are OK with not refcounting here; audit_match_tree()
836  * never dereferences tree and we can't get false positives there
837  * since we'd have to have rule gone from the list *and* removed
838  * before the chunks found by lookup had been allocated, i.e. before
839  * the beginning of list scan.
840  */
841  new->tree = old->tree;
842  memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount);
843 
844  /* deep copy this information, updating the lsm_rule fields, because
845  * the originals will all be freed when the old rule is freed. */
846  for (i = 0; i < fcount; i++) {
847  switch (new->fields[i].type) {
848  case AUDIT_SUBJ_USER:
849  case AUDIT_SUBJ_ROLE:
850  case AUDIT_SUBJ_TYPE:
851  case AUDIT_SUBJ_SEN:
852  case AUDIT_SUBJ_CLR:
853  case AUDIT_OBJ_USER:
854  case AUDIT_OBJ_ROLE:
855  case AUDIT_OBJ_TYPE:
856  case AUDIT_OBJ_LEV_LOW:
857  case AUDIT_OBJ_LEV_HIGH:
858  err = audit_dupe_lsm_field(&new->fields[i],
859  &old->fields[i]);
860  break;
861  case AUDIT_FILTERKEY:
862  fk = kstrdup(old->filterkey, GFP_KERNEL);
863  if (unlikely(!fk))
864  err = -ENOMEM;
865  else
866  new->filterkey = fk;
867  }
868  if (err) {
869  audit_free_rule(entry);
870  return ERR_PTR(err);
871  }
872  }
873 
874  if (old->watch) {
875  audit_get_watch(old->watch);
876  new->watch = old->watch;
877  }
878 
879  return entry;
880 }
881 
882 /* Find an existing audit rule.
883  * Caller must hold audit_filter_mutex to prevent stale rule data. */
884 static struct audit_entry *audit_find_rule(struct audit_entry *entry,
885  struct list_head **p)
886 {
887  struct audit_entry *e, *found = NULL;
888  struct list_head *list;
889  int h;
890 
891  if (entry->rule.inode_f) {
892  h = audit_hash_ino(entry->rule.inode_f->val);
893  *p = list = &audit_inode_hash[h];
894  } else if (entry->rule.watch) {
895  /* we don't know the inode number, so must walk entire hash */
896  for (h = 0; h < AUDIT_INODE_BUCKETS; h++) {
897  list = &audit_inode_hash[h];
898  list_for_each_entry(e, list, list)
899  if (!audit_compare_rule(&entry->rule, &e->rule)) {
900  found = e;
901  goto out;
902  }
903  }
904  goto out;
905  } else {
906  *p = list = &audit_filter_list[entry->rule.listnr];
907  }
908 
909  list_for_each_entry(e, list, list)
910  if (!audit_compare_rule(&entry->rule, &e->rule)) {
911  found = e;
912  goto out;
913  }
914 
915 out:
916  return found;
917 }
918 
919 static u64 prio_low = ~0ULL/2;
920 static u64 prio_high = ~0ULL/2 - 1;
921 
922 /* Add rule to given filterlist if not a duplicate. */
923 static inline int audit_add_rule(struct audit_entry *entry)
924 {
925  struct audit_entry *e;
926  struct audit_watch *watch = entry->rule.watch;
927  struct audit_tree *tree = entry->rule.tree;
928  struct list_head *list;
929  int err;
930 #ifdef CONFIG_AUDITSYSCALL
931  int dont_count = 0;
932 
933  /* If either of these, don't count towards total */
934  if (entry->rule.listnr == AUDIT_FILTER_USER ||
935  entry->rule.listnr == AUDIT_FILTER_TYPE)
936  dont_count = 1;
937 #endif
938 
939  mutex_lock(&audit_filter_mutex);
940  e = audit_find_rule(entry, &list);
941  if (e) {
942  mutex_unlock(&audit_filter_mutex);
943  err = -EEXIST;
944  /* normally audit_add_tree_rule() will free it on failure */
945  if (tree)
946  audit_put_tree(tree);
947  goto error;
948  }
949 
950  if (watch) {
951  /* audit_filter_mutex is dropped and re-taken during this call */
952  err = audit_add_watch(&entry->rule, &list);
953  if (err) {
954  mutex_unlock(&audit_filter_mutex);
955  goto error;
956  }
957  }
958  if (tree) {
959  err = audit_add_tree_rule(&entry->rule);
960  if (err) {
961  mutex_unlock(&audit_filter_mutex);
962  goto error;
963  }
964  }
965 
966  entry->rule.prio = ~0ULL;
967  if (entry->rule.listnr == AUDIT_FILTER_EXIT) {
968  if (entry->rule.flags & AUDIT_FILTER_PREPEND)
969  entry->rule.prio = ++prio_high;
970  else
971  entry->rule.prio = --prio_low;
972  }
973 
974  if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
975  list_add(&entry->rule.list,
976  &audit_rules_list[entry->rule.listnr]);
977  list_add_rcu(&entry->list, list);
978  entry->rule.flags &= ~AUDIT_FILTER_PREPEND;
979  } else {
980  list_add_tail(&entry->rule.list,
981  &audit_rules_list[entry->rule.listnr]);
982  list_add_tail_rcu(&entry->list, list);
983  }
984 #ifdef CONFIG_AUDITSYSCALL
985  if (!dont_count)
986  audit_n_rules++;
987 
988  if (!audit_match_signal(entry))
989  audit_signals++;
990 #endif
991  mutex_unlock(&audit_filter_mutex);
992 
993  return 0;
994 
995 error:
996  if (watch)
997  audit_put_watch(watch); /* tmp watch, matches initial get */
998  return err;
999 }
1000 
1001 /* Remove an existing rule from filterlist. */
1002 static inline int audit_del_rule(struct audit_entry *entry)
1003 {
1004  struct audit_entry *e;
1005  struct audit_watch *watch = entry->rule.watch;
1006  struct audit_tree *tree = entry->rule.tree;
1007  struct list_head *list;
1008  int ret = 0;
1009 #ifdef CONFIG_AUDITSYSCALL
1010  int dont_count = 0;
1011 
1012  /* If either of these, don't count towards total */
1013  if (entry->rule.listnr == AUDIT_FILTER_USER ||
1014  entry->rule.listnr == AUDIT_FILTER_TYPE)
1015  dont_count = 1;
1016 #endif
1017 
1018  mutex_lock(&audit_filter_mutex);
1019  e = audit_find_rule(entry, &list);
1020  if (!e) {
1021  mutex_unlock(&audit_filter_mutex);
1022  ret = -ENOENT;
1023  goto out;
1024  }
1025 
1026  if (e->rule.watch)
1027  audit_remove_watch_rule(&e->rule);
1028 
1029  if (e->rule.tree)
1030  audit_remove_tree_rule(&e->rule);
1031 
1032  list_del_rcu(&e->list);
1033  list_del(&e->rule.list);
1034  call_rcu(&e->rcu, audit_free_rule_rcu);
1035 
1036 #ifdef CONFIG_AUDITSYSCALL
1037  if (!dont_count)
1038  audit_n_rules--;
1039 
1040  if (!audit_match_signal(entry))
1041  audit_signals--;
1042 #endif
1043  mutex_unlock(&audit_filter_mutex);
1044 
1045 out:
1046  if (watch)
1047  audit_put_watch(watch); /* match initial get */
1048  if (tree)
1049  audit_put_tree(tree); /* that's the temporary one */
1050 
1051  return ret;
1052 }
1053 
1054 /* List rules using struct audit_rule. Exists for backward
1055  * compatibility with userspace. */
1056 static void audit_list(int pid, int seq, struct sk_buff_head *q)
1057 {
1058  struct sk_buff *skb;
1059  struct audit_krule *r;
1060  int i;
1061 
1062  /* This is a blocking read, so use audit_filter_mutex instead of rcu
1063  * iterator to sync with list writers. */
1064  for (i=0; i<AUDIT_NR_FILTERS; i++) {
1065  list_for_each_entry(r, &audit_rules_list[i], list) {
1066  struct audit_rule *rule;
1067 
1068  rule = audit_krule_to_rule(r);
1069  if (unlikely(!rule))
1070  break;
1071  skb = audit_make_reply(pid, seq, AUDIT_LIST, 0, 1,
1072  rule, sizeof(*rule));
1073  if (skb)
1074  skb_queue_tail(q, skb);
1075  kfree(rule);
1076  }
1077  }
1078  skb = audit_make_reply(pid, seq, AUDIT_LIST, 1, 1, NULL, 0);
1079  if (skb)
1080  skb_queue_tail(q, skb);
1081 }
1082 
1083 /* List rules using struct audit_rule_data. */
1084 static void audit_list_rules(int pid, int seq, struct sk_buff_head *q)
1085 {
1086  struct sk_buff *skb;
1087  struct audit_krule *r;
1088  int i;
1089 
1090  /* This is a blocking read, so use audit_filter_mutex instead of rcu
1091  * iterator to sync with list writers. */
1092  for (i=0; i<AUDIT_NR_FILTERS; i++) {
1093  list_for_each_entry(r, &audit_rules_list[i], list) {
1094  struct audit_rule_data *data;
1095 
1096  data = audit_krule_to_data(r);
1097  if (unlikely(!data))
1098  break;
1099  skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 0, 1,
1100  data, sizeof(*data) + data->buflen);
1101  if (skb)
1102  skb_queue_tail(q, skb);
1103  kfree(data);
1104  }
1105  }
1106  skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);
1107  if (skb)
1108  skb_queue_tail(q, skb);
1109 }
1110 
1111 /* Log rule additions and removals */
1112 static void audit_log_rule_change(kuid_t loginuid, u32 sessionid, u32 sid,
1113  char *action, struct audit_krule *rule,
1114  int res)
1115 {
1116  struct audit_buffer *ab;
1117 
1118  if (!audit_enabled)
1119  return;
1120 
1121  ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
1122  if (!ab)
1123  return;
1124  audit_log_format(ab, "auid=%u ses=%u",
1125  from_kuid(&init_user_ns, loginuid), sessionid);
1126  if (sid) {
1127  char *ctx = NULL;
1128  u32 len;
1129  if (security_secid_to_secctx(sid, &ctx, &len))
1130  audit_log_format(ab, " ssid=%u", sid);
1131  else {
1132  audit_log_format(ab, " subj=%s", ctx);
1133  security_release_secctx(ctx, len);
1134  }
1135  }
1136  audit_log_format(ab, " op=");
1137  audit_log_string(ab, action);
1138  audit_log_key(ab, rule->filterkey);
1139  audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
1140  audit_log_end(ab);
1141 }
1142 
1155 int audit_receive_filter(int type, int pid, int seq, void *data,
1156  size_t datasz, kuid_t loginuid, u32 sessionid, u32 sid)
1157 {
1158  struct task_struct *tsk;
1159  struct audit_netlink_list *dest;
1160  int err = 0;
1161  struct audit_entry *entry;
1162 
1163  switch (type) {
1164  case AUDIT_LIST:
1165  case AUDIT_LIST_RULES:
1166  /* We can't just spew out the rules here because we might fill
1167  * the available socket buffer space and deadlock waiting for
1168  * auditctl to read from it... which isn't ever going to
1169  * happen if we're actually running in the context of auditctl
1170  * trying to _send_ the stuff */
1171 
1172  dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL);
1173  if (!dest)
1174  return -ENOMEM;
1175  dest->pid = pid;
1176  skb_queue_head_init(&dest->q);
1177 
1178  mutex_lock(&audit_filter_mutex);
1179  if (type == AUDIT_LIST)
1180  audit_list(pid, seq, &dest->q);
1181  else
1182  audit_list_rules(pid, seq, &dest->q);
1183  mutex_unlock(&audit_filter_mutex);
1184 
1185  tsk = kthread_run(audit_send_list, dest, "audit_send_list");
1186  if (IS_ERR(tsk)) {
1187  skb_queue_purge(&dest->q);
1188  kfree(dest);
1189  err = PTR_ERR(tsk);
1190  }
1191  break;
1192  case AUDIT_ADD:
1193  case AUDIT_ADD_RULE:
1194  if (type == AUDIT_ADD)
1195  entry = audit_rule_to_entry(data);
1196  else
1197  entry = audit_data_to_entry(data, datasz);
1198  if (IS_ERR(entry))
1199  return PTR_ERR(entry);
1200 
1201  err = audit_add_rule(entry);
1202  audit_log_rule_change(loginuid, sessionid, sid, "add rule",
1203  &entry->rule, !err);
1204 
1205  if (err)
1206  audit_free_rule(entry);
1207  break;
1208  case AUDIT_DEL:
1209  case AUDIT_DEL_RULE:
1210  if (type == AUDIT_DEL)
1211  entry = audit_rule_to_entry(data);
1212  else
1213  entry = audit_data_to_entry(data, datasz);
1214  if (IS_ERR(entry))
1215  return PTR_ERR(entry);
1216 
1217  err = audit_del_rule(entry);
1218  audit_log_rule_change(loginuid, sessionid, sid, "remove rule",
1219  &entry->rule, !err);
1220 
1221  audit_free_rule(entry);
1222  break;
1223  default:
1224  return -EINVAL;
1225  }
1226 
1227  return err;
1228 }
1229 
1230 int audit_comparator(u32 left, u32 op, u32 right)
1231 {
1232  switch (op) {
1233  case Audit_equal:
1234  return (left == right);
1235  case Audit_not_equal:
1236  return (left != right);
1237  case Audit_lt:
1238  return (left < right);
1239  case Audit_le:
1240  return (left <= right);
1241  case Audit_gt:
1242  return (left > right);
1243  case Audit_ge:
1244  return (left >= right);
1245  case Audit_bitmask:
1246  return (left & right);
1247  case Audit_bittest:
1248  return ((left & right) == right);
1249  default:
1250  BUG();
1251  return 0;
1252  }
1253 }
1254 
1255 int audit_uid_comparator(kuid_t left, u32 op, kuid_t right)
1256 {
1257  switch (op) {
1258  case Audit_equal:
1259  return uid_eq(left, right);
1260  case Audit_not_equal:
1261  return !uid_eq(left, right);
1262  case Audit_lt:
1263  return uid_lt(left, right);
1264  case Audit_le:
1265  return uid_lte(left, right);
1266  case Audit_gt:
1267  return uid_gt(left, right);
1268  case Audit_ge:
1269  return uid_gte(left, right);
1270  case Audit_bitmask:
1271  case Audit_bittest:
1272  default:
1273  BUG();
1274  return 0;
1275  }
1276 }
1277 
1278 int audit_gid_comparator(kgid_t left, u32 op, kgid_t right)
1279 {
1280  switch (op) {
1281  case Audit_equal:
1282  return gid_eq(left, right);
1283  case Audit_not_equal:
1284  return !gid_eq(left, right);
1285  case Audit_lt:
1286  return gid_lt(left, right);
1287  case Audit_le:
1288  return gid_lte(left, right);
1289  case Audit_gt:
1290  return gid_gt(left, right);
1291  case Audit_ge:
1292  return gid_gte(left, right);
1293  case Audit_bitmask:
1294  case Audit_bittest:
1295  default:
1296  BUG();
1297  return 0;
1298  }
1299 }
1300 
1305 int parent_len(const char *path)
1306 {
1307  int plen;
1308  const char *p;
1309 
1310  plen = strlen(path);
1311 
1312  if (plen == 0)
1313  return plen;
1314 
1315  /* disregard trailing slashes */
1316  p = path + plen - 1;
1317  while ((*p == '/') && (p > path))
1318  p--;
1319 
1320  /* walk backward until we find the next slash or hit beginning */
1321  while ((*p != '/') && (p > path))
1322  p--;
1323 
1324  /* did we find a slash? Then increment to include it in path */
1325  if (*p == '/')
1326  p++;
1327 
1328  return p - path;
1329 }
1330 
1339 int audit_compare_dname_path(const char *dname, const char *path, int parentlen)
1340 {
1341  int dlen, pathlen;
1342  const char *p;
1343 
1344  dlen = strlen(dname);
1345  pathlen = strlen(path);
1346  if (pathlen < dlen)
1347  return 1;
1348 
1349  parentlen = parentlen == AUDIT_NAME_FULL ? parent_len(path) : parentlen;
1350  if (pathlen - parentlen != dlen)
1351  return 1;
1352 
1353  p = path + parentlen;
1354 
1355  return strncmp(p, dname, dlen);
1356 }
1357 
1358 static int audit_filter_user_rules(struct audit_krule *rule,
1359  enum audit_state *state)
1360 {
1361  int i;
1362 
1363  for (i = 0; i < rule->field_count; i++) {
1364  struct audit_field *f = &rule->fields[i];
1365  int result = 0;
1366  u32 sid;
1367 
1368  switch (f->type) {
1369  case AUDIT_PID:
1370  result = audit_comparator(task_pid_vnr(current), f->op, f->val);
1371  break;
1372  case AUDIT_UID:
1373  result = audit_uid_comparator(current_uid(), f->op, f->uid);
1374  break;
1375  case AUDIT_GID:
1376  result = audit_gid_comparator(current_gid(), f->op, f->gid);
1377  break;
1378  case AUDIT_LOGINUID:
1379  result = audit_uid_comparator(audit_get_loginuid(current),
1380  f->op, f->uid);
1381  break;
1382  case AUDIT_SUBJ_USER:
1383  case AUDIT_SUBJ_ROLE:
1384  case AUDIT_SUBJ_TYPE:
1385  case AUDIT_SUBJ_SEN:
1386  case AUDIT_SUBJ_CLR:
1387  if (f->lsm_rule) {
1388  security_task_getsecid(current, &sid);
1389  result = security_audit_rule_match(sid,
1390  f->type,
1391  f->op,
1392  f->lsm_rule,
1393  NULL);
1394  }
1395  break;
1396  }
1397 
1398  if (!result)
1399  return 0;
1400  }
1401  switch (rule->action) {
1402  case AUDIT_NEVER: *state = AUDIT_DISABLED; break;
1403  case AUDIT_ALWAYS: *state = AUDIT_RECORD_CONTEXT; break;
1404  }
1405  return 1;
1406 }
1407 
1408 int audit_filter_user(void)
1409 {
1410  enum audit_state state = AUDIT_DISABLED;
1411  struct audit_entry *e;
1412  int ret = 1;
1413 
1414  rcu_read_lock();
1415  list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_USER], list) {
1416  if (audit_filter_user_rules(&e->rule, &state)) {
1417  if (state == AUDIT_DISABLED)
1418  ret = 0;
1419  break;
1420  }
1421  }
1422  rcu_read_unlock();
1423 
1424  return ret; /* Audit by default */
1425 }
1426 
1427 int audit_filter_type(int type)
1428 {
1429  struct audit_entry *e;
1430  int result = 0;
1431 
1432  rcu_read_lock();
1433  if (list_empty(&audit_filter_list[AUDIT_FILTER_TYPE]))
1434  goto unlock_and_return;
1435 
1436  list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_TYPE],
1437  list) {
1438  int i;
1439  for (i = 0; i < e->rule.field_count; i++) {
1440  struct audit_field *f = &e->rule.fields[i];
1441  if (f->type == AUDIT_MSGTYPE) {
1442  result = audit_comparator(type, f->op, f->val);
1443  if (!result)
1444  break;
1445  }
1446  }
1447  if (result)
1448  goto unlock_and_return;
1449  }
1450 unlock_and_return:
1451  rcu_read_unlock();
1452  return result;
1453 }
1454 
1455 static int update_lsm_rule(struct audit_krule *r)
1456 {
1457  struct audit_entry *entry = container_of(r, struct audit_entry, rule);
1458  struct audit_entry *nentry;
1459  int err = 0;
1460 
1461  if (!security_audit_rule_known(r))
1462  return 0;
1463 
1464  nentry = audit_dupe_rule(r);
1465  if (IS_ERR(nentry)) {
1466  /* save the first error encountered for the
1467  * return value */
1468  err = PTR_ERR(nentry);
1469  audit_panic("error updating LSM filters");
1470  if (r->watch)
1471  list_del(&r->rlist);
1472  list_del_rcu(&entry->list);
1473  list_del(&r->list);
1474  } else {
1475  if (r->watch || r->tree)
1476  list_replace_init(&r->rlist, &nentry->rule.rlist);
1477  list_replace_rcu(&entry->list, &nentry->list);
1478  list_replace(&r->list, &nentry->rule.list);
1479  }
1480  call_rcu(&entry->rcu, audit_free_rule_rcu);
1481 
1482  return err;
1483 }
1484 
1485 /* This function will re-initialize the lsm_rule field of all applicable rules.
1486  * It will traverse the filter lists serarching for rules that contain LSM
1487  * specific filter fields. When such a rule is found, it is copied, the
1488  * LSM field is re-initialized, and the old rule is replaced with the
1489  * updated rule. */
1490 int audit_update_lsm_rules(void)
1491 {
1492  struct audit_krule *r, *n;
1493  int i, err = 0;
1494 
1495  /* audit_filter_mutex synchronizes the writers */
1496  mutex_lock(&audit_filter_mutex);
1497 
1498  for (i = 0; i < AUDIT_NR_FILTERS; i++) {
1499  list_for_each_entry_safe(r, n, &audit_rules_list[i], list) {
1500  int res = update_lsm_rule(r);
1501  if (!err)
1502  err = res;
1503  }
1504  }
1505  mutex_unlock(&audit_filter_mutex);
1506 
1507  return err;
1508 }
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