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[GitHub/mt8127/android_kernel_alcatel_ttab.git] / kernel / auditfilter.c
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 if (entry->rule.watch)
598 audit_put_watch(entry->rule.watch); /* matches initial get */
599 if (entry->rule.tree)
600 audit_put_tree(entry->rule.tree); /* that's the temporary one */
601 audit_free_rule(entry);
602 return ERR_PTR(err);
603 }
604
605 /* Pack a filter field's string representation into data block. */
606 static inline size_t audit_pack_string(void **bufp, const char *str)
607 {
608 size_t len = strlen(str);
609
610 memcpy(*bufp, str, len);
611 *bufp += len;
612
613 return len;
614 }
615
616 /* Translate kernel rule respresentation to struct audit_rule.
617 * Exists for backward compatibility with userspace. */
618 static struct audit_rule *audit_krule_to_rule(struct audit_krule *krule)
619 {
620 struct audit_rule *rule;
621 int i;
622
623 rule = kzalloc(sizeof(*rule), GFP_KERNEL);
624 if (unlikely(!rule))
625 return NULL;
626
627 rule->flags = krule->flags | krule->listnr;
628 rule->action = krule->action;
629 rule->field_count = krule->field_count;
630 for (i = 0; i < rule->field_count; i++) {
631 rule->values[i] = krule->fields[i].val;
632 rule->fields[i] = krule->fields[i].type;
633
634 if (krule->vers_ops == 1) {
635 if (krule->fields[i].op == Audit_not_equal)
636 rule->fields[i] |= AUDIT_NEGATE;
637 } else {
638 rule->fields[i] |= audit_ops[krule->fields[i].op];
639 }
640 }
641 for (i = 0; i < AUDIT_BITMASK_SIZE; i++) rule->mask[i] = krule->mask[i];
642
643 return rule;
644 }
645
646 /* Translate kernel rule respresentation to struct audit_rule_data. */
647 static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule)
648 {
649 struct audit_rule_data *data;
650 void *bufp;
651 int i;
652
653 data = kmalloc(sizeof(*data) + krule->buflen, GFP_KERNEL);
654 if (unlikely(!data))
655 return NULL;
656 memset(data, 0, sizeof(*data));
657
658 data->flags = krule->flags | krule->listnr;
659 data->action = krule->action;
660 data->field_count = krule->field_count;
661 bufp = data->buf;
662 for (i = 0; i < data->field_count; i++) {
663 struct audit_field *f = &krule->fields[i];
664
665 data->fields[i] = f->type;
666 data->fieldflags[i] = audit_ops[f->op];
667 switch(f->type) {
668 case AUDIT_SUBJ_USER:
669 case AUDIT_SUBJ_ROLE:
670 case AUDIT_SUBJ_TYPE:
671 case AUDIT_SUBJ_SEN:
672 case AUDIT_SUBJ_CLR:
673 case AUDIT_OBJ_USER:
674 case AUDIT_OBJ_ROLE:
675 case AUDIT_OBJ_TYPE:
676 case AUDIT_OBJ_LEV_LOW:
677 case AUDIT_OBJ_LEV_HIGH:
678 data->buflen += data->values[i] =
679 audit_pack_string(&bufp, f->lsm_str);
680 break;
681 case AUDIT_WATCH:
682 data->buflen += data->values[i] =
683 audit_pack_string(&bufp,
684 audit_watch_path(krule->watch));
685 break;
686 case AUDIT_DIR:
687 data->buflen += data->values[i] =
688 audit_pack_string(&bufp,
689 audit_tree_path(krule->tree));
690 break;
691 case AUDIT_FILTERKEY:
692 data->buflen += data->values[i] =
693 audit_pack_string(&bufp, krule->filterkey);
694 break;
695 default:
696 data->values[i] = f->val;
697 }
698 }
699 for (i = 0; i < AUDIT_BITMASK_SIZE; i++) data->mask[i] = krule->mask[i];
700
701 return data;
702 }
703
704 /* Compare two rules in kernel format. Considered success if rules
705 * don't match. */
706 static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
707 {
708 int i;
709
710 if (a->flags != b->flags ||
711 a->listnr != b->listnr ||
712 a->action != b->action ||
713 a->field_count != b->field_count)
714 return 1;
715
716 for (i = 0; i < a->field_count; i++) {
717 if (a->fields[i].type != b->fields[i].type ||
718 a->fields[i].op != b->fields[i].op)
719 return 1;
720
721 switch(a->fields[i].type) {
722 case AUDIT_SUBJ_USER:
723 case AUDIT_SUBJ_ROLE:
724 case AUDIT_SUBJ_TYPE:
725 case AUDIT_SUBJ_SEN:
726 case AUDIT_SUBJ_CLR:
727 case AUDIT_OBJ_USER:
728 case AUDIT_OBJ_ROLE:
729 case AUDIT_OBJ_TYPE:
730 case AUDIT_OBJ_LEV_LOW:
731 case AUDIT_OBJ_LEV_HIGH:
732 if (strcmp(a->fields[i].lsm_str, b->fields[i].lsm_str))
733 return 1;
734 break;
735 case AUDIT_WATCH:
736 if (strcmp(audit_watch_path(a->watch),
737 audit_watch_path(b->watch)))
738 return 1;
739 break;
740 case AUDIT_DIR:
741 if (strcmp(audit_tree_path(a->tree),
742 audit_tree_path(b->tree)))
743 return 1;
744 break;
745 case AUDIT_FILTERKEY:
746 /* both filterkeys exist based on above type compare */
747 if (strcmp(a->filterkey, b->filterkey))
748 return 1;
749 break;
750 case AUDIT_UID:
751 case AUDIT_EUID:
752 case AUDIT_SUID:
753 case AUDIT_FSUID:
754 case AUDIT_LOGINUID:
755 case AUDIT_OBJ_UID:
756 if (!uid_eq(a->fields[i].uid, b->fields[i].uid))
757 return 1;
758 break;
759 case AUDIT_GID:
760 case AUDIT_EGID:
761 case AUDIT_SGID:
762 case AUDIT_FSGID:
763 case AUDIT_OBJ_GID:
764 if (!gid_eq(a->fields[i].gid, b->fields[i].gid))
765 return 1;
766 break;
767 default:
768 if (a->fields[i].val != b->fields[i].val)
769 return 1;
770 }
771 }
772
773 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
774 if (a->mask[i] != b->mask[i])
775 return 1;
776
777 return 0;
778 }
779
780 /* Duplicate LSM field information. The lsm_rule is opaque, so must be
781 * re-initialized. */
782 static inline int audit_dupe_lsm_field(struct audit_field *df,
783 struct audit_field *sf)
784 {
785 int ret = 0;
786 char *lsm_str;
787
788 /* our own copy of lsm_str */
789 lsm_str = kstrdup(sf->lsm_str, GFP_KERNEL);
790 if (unlikely(!lsm_str))
791 return -ENOMEM;
792 df->lsm_str = lsm_str;
793
794 /* our own (refreshed) copy of lsm_rule */
795 ret = security_audit_rule_init(df->type, df->op, df->lsm_str,
796 (void **)&df->lsm_rule);
797 /* Keep currently invalid fields around in case they
798 * become valid after a policy reload. */
799 if (ret == -EINVAL) {
800 printk(KERN_WARNING "audit rule for LSM \'%s\' is "
801 "invalid\n", df->lsm_str);
802 ret = 0;
803 }
804
805 return ret;
806 }
807
808 /* Duplicate an audit rule. This will be a deep copy with the exception
809 * of the watch - that pointer is carried over. The LSM specific fields
810 * will be updated in the copy. The point is to be able to replace the old
811 * rule with the new rule in the filterlist, then free the old rule.
812 * The rlist element is undefined; list manipulations are handled apart from
813 * the initial copy. */
814 struct audit_entry *audit_dupe_rule(struct audit_krule *old)
815 {
816 u32 fcount = old->field_count;
817 struct audit_entry *entry;
818 struct audit_krule *new;
819 char *fk;
820 int i, err = 0;
821
822 entry = audit_init_entry(fcount);
823 if (unlikely(!entry))
824 return ERR_PTR(-ENOMEM);
825
826 new = &entry->rule;
827 new->vers_ops = old->vers_ops;
828 new->flags = old->flags;
829 new->listnr = old->listnr;
830 new->action = old->action;
831 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
832 new->mask[i] = old->mask[i];
833 new->prio = old->prio;
834 new->buflen = old->buflen;
835 new->inode_f = old->inode_f;
836 new->field_count = old->field_count;
837
838 /*
839 * note that we are OK with not refcounting here; audit_match_tree()
840 * never dereferences tree and we can't get false positives there
841 * since we'd have to have rule gone from the list *and* removed
842 * before the chunks found by lookup had been allocated, i.e. before
843 * the beginning of list scan.
844 */
845 new->tree = old->tree;
846 memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount);
847
848 /* deep copy this information, updating the lsm_rule fields, because
849 * the originals will all be freed when the old rule is freed. */
850 for (i = 0; i < fcount; i++) {
851 switch (new->fields[i].type) {
852 case AUDIT_SUBJ_USER:
853 case AUDIT_SUBJ_ROLE:
854 case AUDIT_SUBJ_TYPE:
855 case AUDIT_SUBJ_SEN:
856 case AUDIT_SUBJ_CLR:
857 case AUDIT_OBJ_USER:
858 case AUDIT_OBJ_ROLE:
859 case AUDIT_OBJ_TYPE:
860 case AUDIT_OBJ_LEV_LOW:
861 case AUDIT_OBJ_LEV_HIGH:
862 err = audit_dupe_lsm_field(&new->fields[i],
863 &old->fields[i]);
864 break;
865 case AUDIT_FILTERKEY:
866 fk = kstrdup(old->filterkey, GFP_KERNEL);
867 if (unlikely(!fk))
868 err = -ENOMEM;
869 else
870 new->filterkey = fk;
871 }
872 if (err) {
873 audit_free_rule(entry);
874 return ERR_PTR(err);
875 }
876 }
877
878 if (old->watch) {
879 audit_get_watch(old->watch);
880 new->watch = old->watch;
881 }
882
883 return entry;
884 }
885
886 /* Find an existing audit rule.
887 * Caller must hold audit_filter_mutex to prevent stale rule data. */
888 static struct audit_entry *audit_find_rule(struct audit_entry *entry,
889 struct list_head **p)
890 {
891 struct audit_entry *e, *found = NULL;
892 struct list_head *list;
893 int h;
894
895 if (entry->rule.inode_f) {
896 h = audit_hash_ino(entry->rule.inode_f->val);
897 *p = list = &audit_inode_hash[h];
898 } else if (entry->rule.watch) {
899 /* we don't know the inode number, so must walk entire hash */
900 for (h = 0; h < AUDIT_INODE_BUCKETS; h++) {
901 list = &audit_inode_hash[h];
902 list_for_each_entry(e, list, list)
903 if (!audit_compare_rule(&entry->rule, &e->rule)) {
904 found = e;
905 goto out;
906 }
907 }
908 goto out;
909 } else {
910 *p = list = &audit_filter_list[entry->rule.listnr];
911 }
912
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 out:
920 return found;
921 }
922
923 static u64 prio_low = ~0ULL/2;
924 static u64 prio_high = ~0ULL/2 - 1;
925
926 /* Add rule to given filterlist if not a duplicate. */
927 static inline int audit_add_rule(struct audit_entry *entry)
928 {
929 struct audit_entry *e;
930 struct audit_watch *watch = entry->rule.watch;
931 struct audit_tree *tree = entry->rule.tree;
932 struct list_head *list;
933 int err;
934 #ifdef CONFIG_AUDITSYSCALL
935 int dont_count = 0;
936
937 /* If either of these, don't count towards total */
938 if (entry->rule.listnr == AUDIT_FILTER_USER ||
939 entry->rule.listnr == AUDIT_FILTER_TYPE)
940 dont_count = 1;
941 #endif
942
943 mutex_lock(&audit_filter_mutex);
944 e = audit_find_rule(entry, &list);
945 if (e) {
946 mutex_unlock(&audit_filter_mutex);
947 err = -EEXIST;
948 /* normally audit_add_tree_rule() will free it on failure */
949 if (tree)
950 audit_put_tree(tree);
951 goto error;
952 }
953
954 if (watch) {
955 /* audit_filter_mutex is dropped and re-taken during this call */
956 err = audit_add_watch(&entry->rule, &list);
957 if (err) {
958 mutex_unlock(&audit_filter_mutex);
959 goto error;
960 }
961 }
962 if (tree) {
963 err = audit_add_tree_rule(&entry->rule);
964 if (err) {
965 mutex_unlock(&audit_filter_mutex);
966 goto error;
967 }
968 }
969
970 entry->rule.prio = ~0ULL;
971 if (entry->rule.listnr == AUDIT_FILTER_EXIT) {
972 if (entry->rule.flags & AUDIT_FILTER_PREPEND)
973 entry->rule.prio = ++prio_high;
974 else
975 entry->rule.prio = --prio_low;
976 }
977
978 if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
979 list_add(&entry->rule.list,
980 &audit_rules_list[entry->rule.listnr]);
981 list_add_rcu(&entry->list, list);
982 entry->rule.flags &= ~AUDIT_FILTER_PREPEND;
983 } else {
984 list_add_tail(&entry->rule.list,
985 &audit_rules_list[entry->rule.listnr]);
986 list_add_tail_rcu(&entry->list, list);
987 }
988 #ifdef CONFIG_AUDITSYSCALL
989 if (!dont_count)
990 audit_n_rules++;
991
992 if (!audit_match_signal(entry))
993 audit_signals++;
994 #endif
995 mutex_unlock(&audit_filter_mutex);
996
997 return 0;
998
999 error:
1000 if (watch)
1001 audit_put_watch(watch); /* tmp watch, matches initial get */
1002 return err;
1003 }
1004
1005 /* Remove an existing rule from filterlist. */
1006 static inline int audit_del_rule(struct audit_entry *entry)
1007 {
1008 struct audit_entry *e;
1009 struct audit_watch *watch = entry->rule.watch;
1010 struct audit_tree *tree = entry->rule.tree;
1011 struct list_head *list;
1012 int ret = 0;
1013 #ifdef CONFIG_AUDITSYSCALL
1014 int dont_count = 0;
1015
1016 /* If either of these, don't count towards total */
1017 if (entry->rule.listnr == AUDIT_FILTER_USER ||
1018 entry->rule.listnr == AUDIT_FILTER_TYPE)
1019 dont_count = 1;
1020 #endif
1021
1022 mutex_lock(&audit_filter_mutex);
1023 e = audit_find_rule(entry, &list);
1024 if (!e) {
1025 mutex_unlock(&audit_filter_mutex);
1026 ret = -ENOENT;
1027 goto out;
1028 }
1029
1030 if (e->rule.watch)
1031 audit_remove_watch_rule(&e->rule);
1032
1033 if (e->rule.tree)
1034 audit_remove_tree_rule(&e->rule);
1035
1036 list_del_rcu(&e->list);
1037 list_del(&e->rule.list);
1038 call_rcu(&e->rcu, audit_free_rule_rcu);
1039
1040 #ifdef CONFIG_AUDITSYSCALL
1041 if (!dont_count)
1042 audit_n_rules--;
1043
1044 if (!audit_match_signal(entry))
1045 audit_signals--;
1046 #endif
1047 mutex_unlock(&audit_filter_mutex);
1048
1049 out:
1050 if (watch)
1051 audit_put_watch(watch); /* match initial get */
1052 if (tree)
1053 audit_put_tree(tree); /* that's the temporary one */
1054
1055 return ret;
1056 }
1057
1058 /* List rules using struct audit_rule. Exists for backward
1059 * compatibility with userspace. */
1060 static void audit_list(int pid, int seq, struct sk_buff_head *q)
1061 {
1062 struct sk_buff *skb;
1063 struct audit_krule *r;
1064 int i;
1065
1066 /* This is a blocking read, so use audit_filter_mutex instead of rcu
1067 * iterator to sync with list writers. */
1068 for (i=0; i<AUDIT_NR_FILTERS; i++) {
1069 list_for_each_entry(r, &audit_rules_list[i], list) {
1070 struct audit_rule *rule;
1071
1072 rule = audit_krule_to_rule(r);
1073 if (unlikely(!rule))
1074 break;
1075 skb = audit_make_reply(pid, seq, AUDIT_LIST, 0, 1,
1076 rule, sizeof(*rule));
1077 if (skb)
1078 skb_queue_tail(q, skb);
1079 kfree(rule);
1080 }
1081 }
1082 skb = audit_make_reply(pid, seq, AUDIT_LIST, 1, 1, NULL, 0);
1083 if (skb)
1084 skb_queue_tail(q, skb);
1085 }
1086
1087 /* List rules using struct audit_rule_data. */
1088 static void audit_list_rules(int pid, int seq, struct sk_buff_head *q)
1089 {
1090 struct sk_buff *skb;
1091 struct audit_krule *r;
1092 int i;
1093
1094 /* This is a blocking read, so use audit_filter_mutex instead of rcu
1095 * iterator to sync with list writers. */
1096 for (i=0; i<AUDIT_NR_FILTERS; i++) {
1097 list_for_each_entry(r, &audit_rules_list[i], list) {
1098 struct audit_rule_data *data;
1099
1100 data = audit_krule_to_data(r);
1101 if (unlikely(!data))
1102 break;
1103 skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 0, 1,
1104 data, sizeof(*data) + data->buflen);
1105 if (skb)
1106 skb_queue_tail(q, skb);
1107 kfree(data);
1108 }
1109 }
1110 skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);
1111 if (skb)
1112 skb_queue_tail(q, skb);
1113 }
1114
1115 /* Log rule additions and removals */
1116 static void audit_log_rule_change(kuid_t loginuid, u32 sessionid, u32 sid,
1117 char *action, struct audit_krule *rule,
1118 int res)
1119 {
1120 struct audit_buffer *ab;
1121
1122 if (!audit_enabled)
1123 return;
1124
1125 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
1126 if (!ab)
1127 return;
1128 audit_log_format(ab, "auid=%u ses=%u",
1129 from_kuid(&init_user_ns, loginuid), sessionid);
1130 if (sid) {
1131 char *ctx = NULL;
1132 u32 len;
1133 if (security_secid_to_secctx(sid, &ctx, &len))
1134 audit_log_format(ab, " ssid=%u", sid);
1135 else {
1136 audit_log_format(ab, " subj=%s", ctx);
1137 security_release_secctx(ctx, len);
1138 }
1139 }
1140 audit_log_format(ab, " op=");
1141 audit_log_string(ab, action);
1142 audit_log_key(ab, rule->filterkey);
1143 audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
1144 audit_log_end(ab);
1145 }
1146
1147 /**
1148 * audit_receive_filter - apply all rules to the specified message type
1149 * @type: audit message type
1150 * @pid: target pid for netlink audit messages
1151 * @seq: netlink audit message sequence (serial) number
1152 * @data: payload data
1153 * @datasz: size of payload data
1154 * @loginuid: loginuid of sender
1155 * @sessionid: sessionid for netlink audit message
1156 * @sid: SE Linux Security ID of sender
1157 */
1158 int audit_receive_filter(int type, int pid, int seq, void *data,
1159 size_t datasz, kuid_t loginuid, u32 sessionid, u32 sid)
1160 {
1161 struct task_struct *tsk;
1162 struct audit_netlink_list *dest;
1163 int err = 0;
1164 struct audit_entry *entry;
1165
1166 switch (type) {
1167 case AUDIT_LIST:
1168 case AUDIT_LIST_RULES:
1169 /* We can't just spew out the rules here because we might fill
1170 * the available socket buffer space and deadlock waiting for
1171 * auditctl to read from it... which isn't ever going to
1172 * happen if we're actually running in the context of auditctl
1173 * trying to _send_ the stuff */
1174
1175 dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL);
1176 if (!dest)
1177 return -ENOMEM;
1178 dest->pid = pid;
1179 skb_queue_head_init(&dest->q);
1180
1181 mutex_lock(&audit_filter_mutex);
1182 if (type == AUDIT_LIST)
1183 audit_list(pid, seq, &dest->q);
1184 else
1185 audit_list_rules(pid, seq, &dest->q);
1186 mutex_unlock(&audit_filter_mutex);
1187
1188 tsk = kthread_run(audit_send_list, dest, "audit_send_list");
1189 if (IS_ERR(tsk)) {
1190 skb_queue_purge(&dest->q);
1191 kfree(dest);
1192 err = PTR_ERR(tsk);
1193 }
1194 break;
1195 case AUDIT_ADD:
1196 case AUDIT_ADD_RULE:
1197 if (type == AUDIT_ADD)
1198 entry = audit_rule_to_entry(data);
1199 else
1200 entry = audit_data_to_entry(data, datasz);
1201 if (IS_ERR(entry))
1202 return PTR_ERR(entry);
1203
1204 err = audit_add_rule(entry);
1205 audit_log_rule_change(loginuid, sessionid, sid, "add rule",
1206 &entry->rule, !err);
1207
1208 if (err)
1209 audit_free_rule(entry);
1210 break;
1211 case AUDIT_DEL:
1212 case AUDIT_DEL_RULE:
1213 if (type == AUDIT_DEL)
1214 entry = audit_rule_to_entry(data);
1215 else
1216 entry = audit_data_to_entry(data, datasz);
1217 if (IS_ERR(entry))
1218 return PTR_ERR(entry);
1219
1220 err = audit_del_rule(entry);
1221 audit_log_rule_change(loginuid, sessionid, sid, "remove rule",
1222 &entry->rule, !err);
1223
1224 audit_free_rule(entry);
1225 break;
1226 default:
1227 return -EINVAL;
1228 }
1229
1230 return err;
1231 }
1232
1233 int audit_comparator(u32 left, u32 op, u32 right)
1234 {
1235 switch (op) {
1236 case Audit_equal:
1237 return (left == right);
1238 case Audit_not_equal:
1239 return (left != right);
1240 case Audit_lt:
1241 return (left < right);
1242 case Audit_le:
1243 return (left <= right);
1244 case Audit_gt:
1245 return (left > right);
1246 case Audit_ge:
1247 return (left >= right);
1248 case Audit_bitmask:
1249 return (left & right);
1250 case Audit_bittest:
1251 return ((left & right) == right);
1252 default:
1253 BUG();
1254 return 0;
1255 }
1256 }
1257
1258 int audit_uid_comparator(kuid_t left, u32 op, kuid_t right)
1259 {
1260 switch (op) {
1261 case Audit_equal:
1262 return uid_eq(left, right);
1263 case Audit_not_equal:
1264 return !uid_eq(left, right);
1265 case Audit_lt:
1266 return uid_lt(left, right);
1267 case Audit_le:
1268 return uid_lte(left, right);
1269 case Audit_gt:
1270 return uid_gt(left, right);
1271 case Audit_ge:
1272 return uid_gte(left, right);
1273 case Audit_bitmask:
1274 case Audit_bittest:
1275 default:
1276 BUG();
1277 return 0;
1278 }
1279 }
1280
1281 int audit_gid_comparator(kgid_t left, u32 op, kgid_t right)
1282 {
1283 switch (op) {
1284 case Audit_equal:
1285 return gid_eq(left, right);
1286 case Audit_not_equal:
1287 return !gid_eq(left, right);
1288 case Audit_lt:
1289 return gid_lt(left, right);
1290 case Audit_le:
1291 return gid_lte(left, right);
1292 case Audit_gt:
1293 return gid_gt(left, right);
1294 case Audit_ge:
1295 return gid_gte(left, right);
1296 case Audit_bitmask:
1297 case Audit_bittest:
1298 default:
1299 BUG();
1300 return 0;
1301 }
1302 }
1303
1304 /**
1305 * parent_len - find the length of the parent portion of a pathname
1306 * @path: pathname of which to determine length
1307 */
1308 int parent_len(const char *path)
1309 {
1310 int plen;
1311 const char *p;
1312
1313 plen = strlen(path);
1314
1315 if (plen == 0)
1316 return plen;
1317
1318 /* disregard trailing slashes */
1319 p = path + plen - 1;
1320 while ((*p == '/') && (p > path))
1321 p--;
1322
1323 /* walk backward until we find the next slash or hit beginning */
1324 while ((*p != '/') && (p > path))
1325 p--;
1326
1327 /* did we find a slash? Then increment to include it in path */
1328 if (*p == '/')
1329 p++;
1330
1331 return p - path;
1332 }
1333
1334 /**
1335 * audit_compare_dname_path - compare given dentry name with last component in
1336 * given path. Return of 0 indicates a match.
1337 * @dname: dentry name that we're comparing
1338 * @path: full pathname that we're comparing
1339 * @parentlen: length of the parent if known. Passing in AUDIT_NAME_FULL
1340 * here indicates that we must compute this value.
1341 */
1342 int audit_compare_dname_path(const char *dname, const char *path, int parentlen)
1343 {
1344 int dlen, pathlen;
1345 const char *p;
1346
1347 dlen = strlen(dname);
1348 pathlen = strlen(path);
1349 if (pathlen < dlen)
1350 return 1;
1351
1352 parentlen = parentlen == AUDIT_NAME_FULL ? parent_len(path) : parentlen;
1353 if (pathlen - parentlen != dlen)
1354 return 1;
1355
1356 p = path + parentlen;
1357
1358 return strncmp(p, dname, dlen);
1359 }
1360
1361 static int audit_filter_user_rules(struct audit_krule *rule,
1362 enum audit_state *state)
1363 {
1364 int i;
1365
1366 for (i = 0; i < rule->field_count; i++) {
1367 struct audit_field *f = &rule->fields[i];
1368 int result = 0;
1369 u32 sid;
1370
1371 switch (f->type) {
1372 case AUDIT_PID:
1373 result = audit_comparator(task_pid_vnr(current), f->op, f->val);
1374 break;
1375 case AUDIT_UID:
1376 result = audit_uid_comparator(current_uid(), f->op, f->uid);
1377 break;
1378 case AUDIT_GID:
1379 result = audit_gid_comparator(current_gid(), f->op, f->gid);
1380 break;
1381 case AUDIT_LOGINUID:
1382 result = audit_uid_comparator(audit_get_loginuid(current),
1383 f->op, f->uid);
1384 break;
1385 case AUDIT_SUBJ_USER:
1386 case AUDIT_SUBJ_ROLE:
1387 case AUDIT_SUBJ_TYPE:
1388 case AUDIT_SUBJ_SEN:
1389 case AUDIT_SUBJ_CLR:
1390 if (f->lsm_rule) {
1391 security_task_getsecid(current, &sid);
1392 result = security_audit_rule_match(sid,
1393 f->type,
1394 f->op,
1395 f->lsm_rule,
1396 NULL);
1397 }
1398 break;
1399 }
1400
1401 if (!result)
1402 return 0;
1403 }
1404 switch (rule->action) {
1405 case AUDIT_NEVER: *state = AUDIT_DISABLED; break;
1406 case AUDIT_ALWAYS: *state = AUDIT_RECORD_CONTEXT; break;
1407 }
1408 return 1;
1409 }
1410
1411 int audit_filter_user(void)
1412 {
1413 enum audit_state state = AUDIT_DISABLED;
1414 struct audit_entry *e;
1415 int ret = 1;
1416
1417 rcu_read_lock();
1418 list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_USER], list) {
1419 if (audit_filter_user_rules(&e->rule, &state)) {
1420 if (state == AUDIT_DISABLED)
1421 ret = 0;
1422 break;
1423 }
1424 }
1425 rcu_read_unlock();
1426
1427 return ret; /* Audit by default */
1428 }
1429
1430 int audit_filter_type(int type)
1431 {
1432 struct audit_entry *e;
1433 int result = 0;
1434
1435 rcu_read_lock();
1436 if (list_empty(&audit_filter_list[AUDIT_FILTER_TYPE]))
1437 goto unlock_and_return;
1438
1439 list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_TYPE],
1440 list) {
1441 int i;
1442 for (i = 0; i < e->rule.field_count; i++) {
1443 struct audit_field *f = &e->rule.fields[i];
1444 if (f->type == AUDIT_MSGTYPE) {
1445 result = audit_comparator(type, f->op, f->val);
1446 if (!result)
1447 break;
1448 }
1449 }
1450 if (result)
1451 goto unlock_and_return;
1452 }
1453 unlock_and_return:
1454 rcu_read_unlock();
1455 return result;
1456 }
1457
1458 static int update_lsm_rule(struct audit_krule *r)
1459 {
1460 struct audit_entry *entry = container_of(r, struct audit_entry, rule);
1461 struct audit_entry *nentry;
1462 int err = 0;
1463
1464 if (!security_audit_rule_known(r))
1465 return 0;
1466
1467 nentry = audit_dupe_rule(r);
1468 if (IS_ERR(nentry)) {
1469 /* save the first error encountered for the
1470 * return value */
1471 err = PTR_ERR(nentry);
1472 audit_panic("error updating LSM filters");
1473 if (r->watch)
1474 list_del(&r->rlist);
1475 list_del_rcu(&entry->list);
1476 list_del(&r->list);
1477 } else {
1478 if (r->watch || r->tree)
1479 list_replace_init(&r->rlist, &nentry->rule.rlist);
1480 list_replace_rcu(&entry->list, &nentry->list);
1481 list_replace(&r->list, &nentry->rule.list);
1482 }
1483 call_rcu(&entry->rcu, audit_free_rule_rcu);
1484
1485 return err;
1486 }
1487
1488 /* This function will re-initialize the lsm_rule field of all applicable rules.
1489 * It will traverse the filter lists serarching for rules that contain LSM
1490 * specific filter fields. When such a rule is found, it is copied, the
1491 * LSM field is re-initialized, and the old rule is replaced with the
1492 * updated rule. */
1493 int audit_update_lsm_rules(void)
1494 {
1495 struct audit_krule *r, *n;
1496 int i, err = 0;
1497
1498 /* audit_filter_mutex synchronizes the writers */
1499 mutex_lock(&audit_filter_mutex);
1500
1501 for (i = 0; i < AUDIT_NR_FILTERS; i++) {
1502 list_for_each_entry_safe(r, n, &audit_rules_list[i], list) {
1503 int res = update_lsm_rule(r);
1504 if (!err)
1505 err = res;
1506 }
1507 }
1508 mutex_unlock(&audit_filter_mutex);
1509
1510 return err;
1511 }
kernel source for telekom puls (alcatel/mediatek)