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audit: make validity checking generic
[deliverable/linux.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 /* check if an audit field is valid */
314 static int audit_field_valid(struct audit_entry *entry, struct audit_field *f)
315 {
316 switch(f->type) {
317 case AUDIT_MSGTYPE:
318 if (entry->rule.listnr != AUDIT_FILTER_TYPE &&
319 entry->rule.listnr != AUDIT_FILTER_USER)
320 return -EINVAL;
321 break;
322 };
323
324 switch(f->type) {
325 default:
326 return -EINVAL;
327 case AUDIT_UID:
328 case AUDIT_EUID:
329 case AUDIT_SUID:
330 case AUDIT_FSUID:
331 case AUDIT_LOGINUID:
332 case AUDIT_OBJ_UID:
333 case AUDIT_GID:
334 case AUDIT_EGID:
335 case AUDIT_SGID:
336 case AUDIT_FSGID:
337 case AUDIT_OBJ_GID:
338 case AUDIT_PID:
339 case AUDIT_PERS:
340 case AUDIT_MSGTYPE:
341 case AUDIT_PPID:
342 case AUDIT_DEVMAJOR:
343 case AUDIT_DEVMINOR:
344 case AUDIT_EXIT:
345 case AUDIT_SUCCESS:
346 /* bit ops are only useful on syscall args */
347 if (f->op == Audit_bitmask || f->op == Audit_bittest)
348 return -EINVAL;
349 break;
350 case AUDIT_ARG0:
351 case AUDIT_ARG1:
352 case AUDIT_ARG2:
353 case AUDIT_ARG3:
354 case AUDIT_SUBJ_USER:
355 case AUDIT_SUBJ_ROLE:
356 case AUDIT_SUBJ_TYPE:
357 case AUDIT_SUBJ_SEN:
358 case AUDIT_SUBJ_CLR:
359 case AUDIT_OBJ_USER:
360 case AUDIT_OBJ_ROLE:
361 case AUDIT_OBJ_TYPE:
362 case AUDIT_OBJ_LEV_LOW:
363 case AUDIT_OBJ_LEV_HIGH:
364 case AUDIT_WATCH:
365 case AUDIT_DIR:
366 case AUDIT_FILTERKEY:
367 break;
368 /* arch is only allowed to be = or != */
369 case AUDIT_ARCH:
370 if (f->op != Audit_not_equal && f->op != Audit_equal)
371 return -EINVAL;
372 break;
373 case AUDIT_PERM:
374 if (f->val & ~15)
375 return -EINVAL;
376 break;
377 case AUDIT_FILETYPE:
378 if (f->val & ~S_IFMT)
379 return -EINVAL;
380 break;
381 case AUDIT_FIELD_COMPARE:
382 if (f->val > AUDIT_MAX_FIELD_COMPARE)
383 return -EINVAL;
384 break;
385 };
386 return 0;
387 }
388
389 /* Translate struct audit_rule to kernel's rule respresentation.
390 * Exists for backward compatibility with userspace. */
391 static struct audit_entry *audit_rule_to_entry(struct audit_rule *rule)
392 {
393 struct audit_entry *entry;
394 int err = 0;
395 int i;
396
397 entry = audit_to_entry_common(rule);
398 if (IS_ERR(entry))
399 goto exit_nofree;
400
401 for (i = 0; i < rule->field_count; i++) {
402 struct audit_field *f = &entry->rule.fields[i];
403 u32 n;
404
405 n = rule->fields[i] & (AUDIT_NEGATE|AUDIT_OPERATORS);
406
407 /* Support for legacy operators where
408 * AUDIT_NEGATE bit signifies != and otherwise assumes == */
409 if (n & AUDIT_NEGATE)
410 f->op = Audit_not_equal;
411 else if (!n)
412 f->op = Audit_equal;
413 else
414 f->op = audit_to_op(n);
415
416 entry->rule.vers_ops = (n & AUDIT_OPERATORS) ? 2 : 1;
417
418 f->type = rule->fields[i] & ~(AUDIT_NEGATE|AUDIT_OPERATORS);
419 f->val = rule->values[i];
420 f->uid = INVALID_UID;
421 f->gid = INVALID_GID;
422
423 err = -EINVAL;
424 if (f->op == Audit_bad)
425 goto exit_free;
426
427 err = audit_field_valid(entry, f);
428 if (err)
429 goto exit_free;
430
431 err = -EINVAL;
432 switch (f->type) {
433 case AUDIT_UID:
434 case AUDIT_EUID:
435 case AUDIT_SUID:
436 case AUDIT_FSUID:
437 case AUDIT_LOGINUID:
438 f->uid = make_kuid(current_user_ns(), f->val);
439 if (!uid_valid(f->uid))
440 goto exit_free;
441 break;
442 case AUDIT_GID:
443 case AUDIT_EGID:
444 case AUDIT_SGID:
445 case AUDIT_FSGID:
446 f->gid = make_kgid(current_user_ns(), f->val);
447 if (!gid_valid(f->gid))
448 goto exit_free;
449 break;
450 case AUDIT_ARCH:
451 entry->rule.arch_f = f;
452 break;
453 case AUDIT_INODE:
454 err = audit_to_inode(&entry->rule, f);
455 if (err)
456 goto exit_free;
457 break;
458 }
459 }
460
461 if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal)
462 entry->rule.inode_f = NULL;
463
464 exit_nofree:
465 return entry;
466
467 exit_free:
468 audit_free_rule(entry);
469 return ERR_PTR(err);
470 }
471
472 /* Translate struct audit_rule_data to kernel's rule respresentation. */
473 static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
474 size_t datasz)
475 {
476 int err = 0;
477 struct audit_entry *entry;
478 void *bufp;
479 size_t remain = datasz - sizeof(struct audit_rule_data);
480 int i;
481 char *str;
482
483 entry = audit_to_entry_common((struct audit_rule *)data);
484 if (IS_ERR(entry))
485 goto exit_nofree;
486
487 bufp = data->buf;
488 entry->rule.vers_ops = 2;
489 for (i = 0; i < data->field_count; i++) {
490 struct audit_field *f = &entry->rule.fields[i];
491
492 err = -EINVAL;
493
494 f->op = audit_to_op(data->fieldflags[i]);
495 if (f->op == Audit_bad)
496 goto exit_free;
497
498 f->type = data->fields[i];
499 f->val = data->values[i];
500 f->uid = INVALID_UID;
501 f->gid = INVALID_GID;
502 f->lsm_str = NULL;
503 f->lsm_rule = NULL;
504
505 err = audit_field_valid(entry, f);
506 if (err)
507 goto exit_free;
508
509 err = -EINVAL;
510 switch (f->type) {
511 case AUDIT_UID:
512 case AUDIT_EUID:
513 case AUDIT_SUID:
514 case AUDIT_FSUID:
515 case AUDIT_LOGINUID:
516 case AUDIT_OBJ_UID:
517 f->uid = make_kuid(current_user_ns(), f->val);
518 if (!uid_valid(f->uid))
519 goto exit_free;
520 break;
521 case AUDIT_GID:
522 case AUDIT_EGID:
523 case AUDIT_SGID:
524 case AUDIT_FSGID:
525 case AUDIT_OBJ_GID:
526 f->gid = make_kgid(current_user_ns(), f->val);
527 if (!gid_valid(f->gid))
528 goto exit_free;
529 break;
530 case AUDIT_ARCH:
531 entry->rule.arch_f = f;
532 break;
533 case AUDIT_SUBJ_USER:
534 case AUDIT_SUBJ_ROLE:
535 case AUDIT_SUBJ_TYPE:
536 case AUDIT_SUBJ_SEN:
537 case AUDIT_SUBJ_CLR:
538 case AUDIT_OBJ_USER:
539 case AUDIT_OBJ_ROLE:
540 case AUDIT_OBJ_TYPE:
541 case AUDIT_OBJ_LEV_LOW:
542 case AUDIT_OBJ_LEV_HIGH:
543 str = audit_unpack_string(&bufp, &remain, f->val);
544 if (IS_ERR(str))
545 goto exit_free;
546 entry->rule.buflen += f->val;
547
548 err = security_audit_rule_init(f->type, f->op, str,
549 (void **)&f->lsm_rule);
550 /* Keep currently invalid fields around in case they
551 * become valid after a policy reload. */
552 if (err == -EINVAL) {
553 printk(KERN_WARNING "audit rule for LSM "
554 "\'%s\' is invalid\n", str);
555 err = 0;
556 }
557 if (err) {
558 kfree(str);
559 goto exit_free;
560 } else
561 f->lsm_str = str;
562 break;
563 case AUDIT_WATCH:
564 str = audit_unpack_string(&bufp, &remain, f->val);
565 if (IS_ERR(str))
566 goto exit_free;
567 entry->rule.buflen += f->val;
568
569 err = audit_to_watch(&entry->rule, str, f->val, f->op);
570 if (err) {
571 kfree(str);
572 goto exit_free;
573 }
574 break;
575 case AUDIT_DIR:
576 str = audit_unpack_string(&bufp, &remain, f->val);
577 if (IS_ERR(str))
578 goto exit_free;
579 entry->rule.buflen += f->val;
580
581 err = audit_make_tree(&entry->rule, str, f->op);
582 kfree(str);
583 if (err)
584 goto exit_free;
585 break;
586 case AUDIT_INODE:
587 err = audit_to_inode(&entry->rule, f);
588 if (err)
589 goto exit_free;
590 break;
591 case AUDIT_FILTERKEY:
592 if (entry->rule.filterkey || f->val > AUDIT_MAX_KEY_LEN)
593 goto exit_free;
594 str = audit_unpack_string(&bufp, &remain, f->val);
595 if (IS_ERR(str))
596 goto exit_free;
597 entry->rule.buflen += f->val;
598 entry->rule.filterkey = str;
599 break;
600 }
601 }
602
603 if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal)
604 entry->rule.inode_f = NULL;
605
606 exit_nofree:
607 return entry;
608
609 exit_free:
610 audit_free_rule(entry);
611 return ERR_PTR(err);
612 }
613
614 /* Pack a filter field's string representation into data block. */
615 static 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 respresentation to struct audit_rule.
626 * Exists for backward compatibility with userspace. */
627 static struct audit_rule *audit_krule_to_rule(struct audit_krule *krule)
628 {
629 struct audit_rule *rule;
630 int i;
631
632 rule = kzalloc(sizeof(*rule), GFP_KERNEL);
633 if (unlikely(!rule))
634 return NULL;
635
636 rule->flags = krule->flags | krule->listnr;
637 rule->action = krule->action;
638 rule->field_count = krule->field_count;
639 for (i = 0; i < rule->field_count; i++) {
640 rule->values[i] = krule->fields[i].val;
641 rule->fields[i] = krule->fields[i].type;
642
643 if (krule->vers_ops == 1) {
644 if (krule->fields[i].op == Audit_not_equal)
645 rule->fields[i] |= AUDIT_NEGATE;
646 } else {
647 rule->fields[i] |= audit_ops[krule->fields[i].op];
648 }
649 }
650 for (i = 0; i < AUDIT_BITMASK_SIZE; i++) rule->mask[i] = krule->mask[i];
651
652 return rule;
653 }
654
655 /* Translate kernel rule respresentation to struct audit_rule_data. */
656 static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule)
657 {
658 struct audit_rule_data *data;
659 void *bufp;
660 int i;
661
662 data = kmalloc(sizeof(*data) + krule->buflen, GFP_KERNEL);
663 if (unlikely(!data))
664 return NULL;
665 memset(data, 0, sizeof(*data));
666
667 data->flags = krule->flags | krule->listnr;
668 data->action = krule->action;
669 data->field_count = krule->field_count;
670 bufp = data->buf;
671 for (i = 0; i < data->field_count; i++) {
672 struct audit_field *f = &krule->fields[i];
673
674 data->fields[i] = f->type;
675 data->fieldflags[i] = audit_ops[f->op];
676 switch(f->type) {
677 case AUDIT_SUBJ_USER:
678 case AUDIT_SUBJ_ROLE:
679 case AUDIT_SUBJ_TYPE:
680 case AUDIT_SUBJ_SEN:
681 case AUDIT_SUBJ_CLR:
682 case AUDIT_OBJ_USER:
683 case AUDIT_OBJ_ROLE:
684 case AUDIT_OBJ_TYPE:
685 case AUDIT_OBJ_LEV_LOW:
686 case AUDIT_OBJ_LEV_HIGH:
687 data->buflen += data->values[i] =
688 audit_pack_string(&bufp, f->lsm_str);
689 break;
690 case AUDIT_WATCH:
691 data->buflen += data->values[i] =
692 audit_pack_string(&bufp,
693 audit_watch_path(krule->watch));
694 break;
695 case AUDIT_DIR:
696 data->buflen += data->values[i] =
697 audit_pack_string(&bufp,
698 audit_tree_path(krule->tree));
699 break;
700 case AUDIT_FILTERKEY:
701 data->buflen += data->values[i] =
702 audit_pack_string(&bufp, krule->filterkey);
703 break;
704 default:
705 data->values[i] = f->val;
706 }
707 }
708 for (i = 0; i < AUDIT_BITMASK_SIZE; i++) data->mask[i] = krule->mask[i];
709
710 return data;
711 }
712
713 /* Compare two rules in kernel format. Considered success if rules
714 * don't match. */
715 static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
716 {
717 int i;
718
719 if (a->flags != b->flags ||
720 a->listnr != b->listnr ||
721 a->action != b->action ||
722 a->field_count != b->field_count)
723 return 1;
724
725 for (i = 0; i < a->field_count; i++) {
726 if (a->fields[i].type != b->fields[i].type ||
727 a->fields[i].op != b->fields[i].op)
728 return 1;
729
730 switch(a->fields[i].type) {
731 case AUDIT_SUBJ_USER:
732 case AUDIT_SUBJ_ROLE:
733 case AUDIT_SUBJ_TYPE:
734 case AUDIT_SUBJ_SEN:
735 case AUDIT_SUBJ_CLR:
736 case AUDIT_OBJ_USER:
737 case AUDIT_OBJ_ROLE:
738 case AUDIT_OBJ_TYPE:
739 case AUDIT_OBJ_LEV_LOW:
740 case AUDIT_OBJ_LEV_HIGH:
741 if (strcmp(a->fields[i].lsm_str, b->fields[i].lsm_str))
742 return 1;
743 break;
744 case AUDIT_WATCH:
745 if (strcmp(audit_watch_path(a->watch),
746 audit_watch_path(b->watch)))
747 return 1;
748 break;
749 case AUDIT_DIR:
750 if (strcmp(audit_tree_path(a->tree),
751 audit_tree_path(b->tree)))
752 return 1;
753 break;
754 case AUDIT_FILTERKEY:
755 /* both filterkeys exist based on above type compare */
756 if (strcmp(a->filterkey, b->filterkey))
757 return 1;
758 break;
759 case AUDIT_UID:
760 case AUDIT_EUID:
761 case AUDIT_SUID:
762 case AUDIT_FSUID:
763 case AUDIT_LOGINUID:
764 case AUDIT_OBJ_UID:
765 if (!uid_eq(a->fields[i].uid, b->fields[i].uid))
766 return 1;
767 break;
768 case AUDIT_GID:
769 case AUDIT_EGID:
770 case AUDIT_SGID:
771 case AUDIT_FSGID:
772 case AUDIT_OBJ_GID:
773 if (!gid_eq(a->fields[i].gid, b->fields[i].gid))
774 return 1;
775 break;
776 default:
777 if (a->fields[i].val != b->fields[i].val)
778 return 1;
779 }
780 }
781
782 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
783 if (a->mask[i] != b->mask[i])
784 return 1;
785
786 return 0;
787 }
788
789 /* Duplicate LSM field information. The lsm_rule is opaque, so must be
790 * re-initialized. */
791 static inline int audit_dupe_lsm_field(struct audit_field *df,
792 struct audit_field *sf)
793 {
794 int ret = 0;
795 char *lsm_str;
796
797 /* our own copy of lsm_str */
798 lsm_str = kstrdup(sf->lsm_str, GFP_KERNEL);
799 if (unlikely(!lsm_str))
800 return -ENOMEM;
801 df->lsm_str = lsm_str;
802
803 /* our own (refreshed) copy of lsm_rule */
804 ret = security_audit_rule_init(df->type, df->op, df->lsm_str,
805 (void **)&df->lsm_rule);
806 /* Keep currently invalid fields around in case they
807 * become valid after a policy reload. */
808 if (ret == -EINVAL) {
809 printk(KERN_WARNING "audit rule for LSM \'%s\' is "
810 "invalid\n", df->lsm_str);
811 ret = 0;
812 }
813
814 return ret;
815 }
816
817 /* Duplicate an audit rule. This will be a deep copy with the exception
818 * of the watch - that pointer is carried over. The LSM specific fields
819 * will be updated in the copy. The point is to be able to replace the old
820 * rule with the new rule in the filterlist, then free the old rule.
821 * The rlist element is undefined; list manipulations are handled apart from
822 * the initial copy. */
823 struct audit_entry *audit_dupe_rule(struct audit_krule *old)
824 {
825 u32 fcount = old->field_count;
826 struct audit_entry *entry;
827 struct audit_krule *new;
828 char *fk;
829 int i, err = 0;
830
831 entry = audit_init_entry(fcount);
832 if (unlikely(!entry))
833 return ERR_PTR(-ENOMEM);
834
835 new = &entry->rule;
836 new->vers_ops = old->vers_ops;
837 new->flags = old->flags;
838 new->listnr = old->listnr;
839 new->action = old->action;
840 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
841 new->mask[i] = old->mask[i];
842 new->prio = old->prio;
843 new->buflen = old->buflen;
844 new->inode_f = old->inode_f;
845 new->field_count = old->field_count;
846
847 /*
848 * note that we are OK with not refcounting here; audit_match_tree()
849 * never dereferences tree and we can't get false positives there
850 * since we'd have to have rule gone from the list *and* removed
851 * before the chunks found by lookup had been allocated, i.e. before
852 * the beginning of list scan.
853 */
854 new->tree = old->tree;
855 memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount);
856
857 /* deep copy this information, updating the lsm_rule fields, because
858 * the originals will all be freed when the old rule is freed. */
859 for (i = 0; i < fcount; i++) {
860 switch (new->fields[i].type) {
861 case AUDIT_SUBJ_USER:
862 case AUDIT_SUBJ_ROLE:
863 case AUDIT_SUBJ_TYPE:
864 case AUDIT_SUBJ_SEN:
865 case AUDIT_SUBJ_CLR:
866 case AUDIT_OBJ_USER:
867 case AUDIT_OBJ_ROLE:
868 case AUDIT_OBJ_TYPE:
869 case AUDIT_OBJ_LEV_LOW:
870 case AUDIT_OBJ_LEV_HIGH:
871 err = audit_dupe_lsm_field(&new->fields[i],
872 &old->fields[i]);
873 break;
874 case AUDIT_FILTERKEY:
875 fk = kstrdup(old->filterkey, GFP_KERNEL);
876 if (unlikely(!fk))
877 err = -ENOMEM;
878 else
879 new->filterkey = fk;
880 }
881 if (err) {
882 audit_free_rule(entry);
883 return ERR_PTR(err);
884 }
885 }
886
887 if (old->watch) {
888 audit_get_watch(old->watch);
889 new->watch = old->watch;
890 }
891
892 return entry;
893 }
894
895 /* Find an existing audit rule.
896 * Caller must hold audit_filter_mutex to prevent stale rule data. */
897 static struct audit_entry *audit_find_rule(struct audit_entry *entry,
898 struct list_head **p)
899 {
900 struct audit_entry *e, *found = NULL;
901 struct list_head *list;
902 int h;
903
904 if (entry->rule.inode_f) {
905 h = audit_hash_ino(entry->rule.inode_f->val);
906 *p = list = &audit_inode_hash[h];
907 } else if (entry->rule.watch) {
908 /* we don't know the inode number, so must walk entire hash */
909 for (h = 0; h < AUDIT_INODE_BUCKETS; h++) {
910 list = &audit_inode_hash[h];
911 list_for_each_entry(e, list, list)
912 if (!audit_compare_rule(&entry->rule, &e->rule)) {
913 found = e;
914 goto out;
915 }
916 }
917 goto out;
918 } else {
919 *p = list = &audit_filter_list[entry->rule.listnr];
920 }
921
922 list_for_each_entry(e, list, list)
923 if (!audit_compare_rule(&entry->rule, &e->rule)) {
924 found = e;
925 goto out;
926 }
927
928 out:
929 return found;
930 }
931
932 static u64 prio_low = ~0ULL/2;
933 static u64 prio_high = ~0ULL/2 - 1;
934
935 /* Add rule to given filterlist if not a duplicate. */
936 static inline int audit_add_rule(struct audit_entry *entry)
937 {
938 struct audit_entry *e;
939 struct audit_watch *watch = entry->rule.watch;
940 struct audit_tree *tree = entry->rule.tree;
941 struct list_head *list;
942 int err;
943 #ifdef CONFIG_AUDITSYSCALL
944 int dont_count = 0;
945
946 /* If either of these, don't count towards total */
947 if (entry->rule.listnr == AUDIT_FILTER_USER ||
948 entry->rule.listnr == AUDIT_FILTER_TYPE)
949 dont_count = 1;
950 #endif
951
952 mutex_lock(&audit_filter_mutex);
953 e = audit_find_rule(entry, &list);
954 if (e) {
955 mutex_unlock(&audit_filter_mutex);
956 err = -EEXIST;
957 /* normally audit_add_tree_rule() will free it on failure */
958 if (tree)
959 audit_put_tree(tree);
960 goto error;
961 }
962
963 if (watch) {
964 /* audit_filter_mutex is dropped and re-taken during this call */
965 err = audit_add_watch(&entry->rule, &list);
966 if (err) {
967 mutex_unlock(&audit_filter_mutex);
968 goto error;
969 }
970 }
971 if (tree) {
972 err = audit_add_tree_rule(&entry->rule);
973 if (err) {
974 mutex_unlock(&audit_filter_mutex);
975 goto error;
976 }
977 }
978
979 entry->rule.prio = ~0ULL;
980 if (entry->rule.listnr == AUDIT_FILTER_EXIT) {
981 if (entry->rule.flags & AUDIT_FILTER_PREPEND)
982 entry->rule.prio = ++prio_high;
983 else
984 entry->rule.prio = --prio_low;
985 }
986
987 if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
988 list_add(&entry->rule.list,
989 &audit_rules_list[entry->rule.listnr]);
990 list_add_rcu(&entry->list, list);
991 entry->rule.flags &= ~AUDIT_FILTER_PREPEND;
992 } else {
993 list_add_tail(&entry->rule.list,
994 &audit_rules_list[entry->rule.listnr]);
995 list_add_tail_rcu(&entry->list, list);
996 }
997 #ifdef CONFIG_AUDITSYSCALL
998 if (!dont_count)
999 audit_n_rules++;
1000
1001 if (!audit_match_signal(entry))
1002 audit_signals++;
1003 #endif
1004 mutex_unlock(&audit_filter_mutex);
1005
1006 return 0;
1007
1008 error:
1009 if (watch)
1010 audit_put_watch(watch); /* tmp watch, matches initial get */
1011 return err;
1012 }
1013
1014 /* Remove an existing rule from filterlist. */
1015 static inline int audit_del_rule(struct audit_entry *entry)
1016 {
1017 struct audit_entry *e;
1018 struct audit_watch *watch = entry->rule.watch;
1019 struct audit_tree *tree = entry->rule.tree;
1020 struct list_head *list;
1021 int ret = 0;
1022 #ifdef CONFIG_AUDITSYSCALL
1023 int dont_count = 0;
1024
1025 /* If either of these, don't count towards total */
1026 if (entry->rule.listnr == AUDIT_FILTER_USER ||
1027 entry->rule.listnr == AUDIT_FILTER_TYPE)
1028 dont_count = 1;
1029 #endif
1030
1031 mutex_lock(&audit_filter_mutex);
1032 e = audit_find_rule(entry, &list);
1033 if (!e) {
1034 mutex_unlock(&audit_filter_mutex);
1035 ret = -ENOENT;
1036 goto out;
1037 }
1038
1039 if (e->rule.watch)
1040 audit_remove_watch_rule(&e->rule);
1041
1042 if (e->rule.tree)
1043 audit_remove_tree_rule(&e->rule);
1044
1045 list_del_rcu(&e->list);
1046 list_del(&e->rule.list);
1047 call_rcu(&e->rcu, audit_free_rule_rcu);
1048
1049 #ifdef CONFIG_AUDITSYSCALL
1050 if (!dont_count)
1051 audit_n_rules--;
1052
1053 if (!audit_match_signal(entry))
1054 audit_signals--;
1055 #endif
1056 mutex_unlock(&audit_filter_mutex);
1057
1058 out:
1059 if (watch)
1060 audit_put_watch(watch); /* match initial get */
1061 if (tree)
1062 audit_put_tree(tree); /* that's the temporary one */
1063
1064 return ret;
1065 }
1066
1067 /* List rules using struct audit_rule. Exists for backward
1068 * compatibility with userspace. */
1069 static void audit_list(int pid, 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 *rule;
1080
1081 rule = audit_krule_to_rule(r);
1082 if (unlikely(!rule))
1083 break;
1084 skb = audit_make_reply(pid, seq, AUDIT_LIST, 0, 1,
1085 rule, sizeof(*rule));
1086 if (skb)
1087 skb_queue_tail(q, skb);
1088 kfree(rule);
1089 }
1090 }
1091 skb = audit_make_reply(pid, seq, AUDIT_LIST, 1, 1, NULL, 0);
1092 if (skb)
1093 skb_queue_tail(q, skb);
1094 }
1095
1096 /* List rules using struct audit_rule_data. */
1097 static void audit_list_rules(int pid, int seq, struct sk_buff_head *q)
1098 {
1099 struct sk_buff *skb;
1100 struct audit_krule *r;
1101 int i;
1102
1103 /* This is a blocking read, so use audit_filter_mutex instead of rcu
1104 * iterator to sync with list writers. */
1105 for (i=0; i<AUDIT_NR_FILTERS; i++) {
1106 list_for_each_entry(r, &audit_rules_list[i], list) {
1107 struct audit_rule_data *data;
1108
1109 data = audit_krule_to_data(r);
1110 if (unlikely(!data))
1111 break;
1112 skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 0, 1,
1113 data, sizeof(*data) + data->buflen);
1114 if (skb)
1115 skb_queue_tail(q, skb);
1116 kfree(data);
1117 }
1118 }
1119 skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);
1120 if (skb)
1121 skb_queue_tail(q, skb);
1122 }
1123
1124 /* Log rule additions and removals */
1125 static void audit_log_rule_change(kuid_t loginuid, u32 sessionid, u32 sid,
1126 char *action, struct audit_krule *rule,
1127 int res)
1128 {
1129 struct audit_buffer *ab;
1130
1131 if (!audit_enabled)
1132 return;
1133
1134 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
1135 if (!ab)
1136 return;
1137 audit_log_format(ab, "auid=%u ses=%u",
1138 from_kuid(&init_user_ns, loginuid), sessionid);
1139 if (sid) {
1140 char *ctx = NULL;
1141 u32 len;
1142 if (security_secid_to_secctx(sid, &ctx, &len))
1143 audit_log_format(ab, " ssid=%u", sid);
1144 else {
1145 audit_log_format(ab, " subj=%s", ctx);
1146 security_release_secctx(ctx, len);
1147 }
1148 }
1149 audit_log_format(ab, " op=");
1150 audit_log_string(ab, action);
1151 audit_log_key(ab, rule->filterkey);
1152 audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
1153 audit_log_end(ab);
1154 }
1155
1156 /**
1157 * audit_receive_filter - apply all rules to the specified message type
1158 * @type: audit message type
1159 * @pid: target pid for netlink audit messages
1160 * @seq: netlink audit message sequence (serial) number
1161 * @data: payload data
1162 * @datasz: size of payload data
1163 * @loginuid: loginuid of sender
1164 * @sessionid: sessionid for netlink audit message
1165 * @sid: SE Linux Security ID of sender
1166 */
1167 int audit_receive_filter(int type, int pid, int seq, void *data,
1168 size_t datasz, kuid_t loginuid, u32 sessionid, u32 sid)
1169 {
1170 struct task_struct *tsk;
1171 struct audit_netlink_list *dest;
1172 int err = 0;
1173 struct audit_entry *entry;
1174
1175 switch (type) {
1176 case AUDIT_LIST:
1177 case AUDIT_LIST_RULES:
1178 /* We can't just spew out the rules here because we might fill
1179 * the available socket buffer space and deadlock waiting for
1180 * auditctl to read from it... which isn't ever going to
1181 * happen if we're actually running in the context of auditctl
1182 * trying to _send_ the stuff */
1183
1184 dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL);
1185 if (!dest)
1186 return -ENOMEM;
1187 dest->pid = pid;
1188 skb_queue_head_init(&dest->q);
1189
1190 mutex_lock(&audit_filter_mutex);
1191 if (type == AUDIT_LIST)
1192 audit_list(pid, seq, &dest->q);
1193 else
1194 audit_list_rules(pid, seq, &dest->q);
1195 mutex_unlock(&audit_filter_mutex);
1196
1197 tsk = kthread_run(audit_send_list, dest, "audit_send_list");
1198 if (IS_ERR(tsk)) {
1199 skb_queue_purge(&dest->q);
1200 kfree(dest);
1201 err = PTR_ERR(tsk);
1202 }
1203 break;
1204 case AUDIT_ADD:
1205 case AUDIT_ADD_RULE:
1206 if (type == AUDIT_ADD)
1207 entry = audit_rule_to_entry(data);
1208 else
1209 entry = audit_data_to_entry(data, datasz);
1210 if (IS_ERR(entry))
1211 return PTR_ERR(entry);
1212
1213 err = audit_add_rule(entry);
1214 audit_log_rule_change(loginuid, sessionid, sid, "add rule",
1215 &entry->rule, !err);
1216
1217 if (err)
1218 audit_free_rule(entry);
1219 break;
1220 case AUDIT_DEL:
1221 case AUDIT_DEL_RULE:
1222 if (type == AUDIT_DEL)
1223 entry = audit_rule_to_entry(data);
1224 else
1225 entry = audit_data_to_entry(data, datasz);
1226 if (IS_ERR(entry))
1227 return PTR_ERR(entry);
1228
1229 err = audit_del_rule(entry);
1230 audit_log_rule_change(loginuid, sessionid, sid, "remove rule",
1231 &entry->rule, !err);
1232
1233 audit_free_rule(entry);
1234 break;
1235 default:
1236 return -EINVAL;
1237 }
1238
1239 return err;
1240 }
1241
1242 int audit_comparator(u32 left, u32 op, u32 right)
1243 {
1244 switch (op) {
1245 case Audit_equal:
1246 return (left == right);
1247 case Audit_not_equal:
1248 return (left != right);
1249 case Audit_lt:
1250 return (left < right);
1251 case Audit_le:
1252 return (left <= right);
1253 case Audit_gt:
1254 return (left > right);
1255 case Audit_ge:
1256 return (left >= right);
1257 case Audit_bitmask:
1258 return (left & right);
1259 case Audit_bittest:
1260 return ((left & right) == right);
1261 default:
1262 BUG();
1263 return 0;
1264 }
1265 }
1266
1267 int audit_uid_comparator(kuid_t left, u32 op, kuid_t right)
1268 {
1269 switch (op) {
1270 case Audit_equal:
1271 return uid_eq(left, right);
1272 case Audit_not_equal:
1273 return !uid_eq(left, right);
1274 case Audit_lt:
1275 return uid_lt(left, right);
1276 case Audit_le:
1277 return uid_lte(left, right);
1278 case Audit_gt:
1279 return uid_gt(left, right);
1280 case Audit_ge:
1281 return uid_gte(left, right);
1282 case Audit_bitmask:
1283 case Audit_bittest:
1284 default:
1285 BUG();
1286 return 0;
1287 }
1288 }
1289
1290 int audit_gid_comparator(kgid_t left, u32 op, kgid_t right)
1291 {
1292 switch (op) {
1293 case Audit_equal:
1294 return gid_eq(left, right);
1295 case Audit_not_equal:
1296 return !gid_eq(left, right);
1297 case Audit_lt:
1298 return gid_lt(left, right);
1299 case Audit_le:
1300 return gid_lte(left, right);
1301 case Audit_gt:
1302 return gid_gt(left, right);
1303 case Audit_ge:
1304 return gid_gte(left, right);
1305 case Audit_bitmask:
1306 case Audit_bittest:
1307 default:
1308 BUG();
1309 return 0;
1310 }
1311 }
1312
1313 /**
1314 * parent_len - find the length of the parent portion of a pathname
1315 * @path: pathname of which to determine length
1316 */
1317 int parent_len(const char *path)
1318 {
1319 int plen;
1320 const char *p;
1321
1322 plen = strlen(path);
1323
1324 if (plen == 0)
1325 return plen;
1326
1327 /* disregard trailing slashes */
1328 p = path + plen - 1;
1329 while ((*p == '/') && (p > path))
1330 p--;
1331
1332 /* walk backward until we find the next slash or hit beginning */
1333 while ((*p != '/') && (p > path))
1334 p--;
1335
1336 /* did we find a slash? Then increment to include it in path */
1337 if (*p == '/')
1338 p++;
1339
1340 return p - path;
1341 }
1342
1343 /**
1344 * audit_compare_dname_path - compare given dentry name with last component in
1345 * given path. Return of 0 indicates a match.
1346 * @dname: dentry name that we're comparing
1347 * @path: full pathname that we're comparing
1348 * @parentlen: length of the parent if known. Passing in AUDIT_NAME_FULL
1349 * here indicates that we must compute this value.
1350 */
1351 int audit_compare_dname_path(const char *dname, const char *path, int parentlen)
1352 {
1353 int dlen, pathlen;
1354 const char *p;
1355
1356 dlen = strlen(dname);
1357 pathlen = strlen(path);
1358 if (pathlen < dlen)
1359 return 1;
1360
1361 parentlen = parentlen == AUDIT_NAME_FULL ? parent_len(path) : parentlen;
1362 if (pathlen - parentlen != dlen)
1363 return 1;
1364
1365 p = path + parentlen;
1366
1367 return strncmp(p, dname, dlen);
1368 }
1369
1370 static int audit_filter_user_rules(struct audit_krule *rule, int type,
1371 enum audit_state *state)
1372 {
1373 int i;
1374
1375 for (i = 0; i < rule->field_count; i++) {
1376 struct audit_field *f = &rule->fields[i];
1377 int result = 0;
1378 u32 sid;
1379
1380 switch (f->type) {
1381 case AUDIT_PID:
1382 result = audit_comparator(task_pid_vnr(current), f->op, f->val);
1383 break;
1384 case AUDIT_UID:
1385 result = audit_uid_comparator(current_uid(), f->op, f->uid);
1386 break;
1387 case AUDIT_GID:
1388 result = audit_gid_comparator(current_gid(), f->op, f->gid);
1389 break;
1390 case AUDIT_LOGINUID:
1391 result = audit_uid_comparator(audit_get_loginuid(current),
1392 f->op, f->uid);
1393 break;
1394 case AUDIT_MSGTYPE:
1395 result = audit_comparator(type, f->op, f->val);
1396 break;
1397 case AUDIT_SUBJ_USER:
1398 case AUDIT_SUBJ_ROLE:
1399 case AUDIT_SUBJ_TYPE:
1400 case AUDIT_SUBJ_SEN:
1401 case AUDIT_SUBJ_CLR:
1402 if (f->lsm_rule) {
1403 security_task_getsecid(current, &sid);
1404 result = security_audit_rule_match(sid,
1405 f->type,
1406 f->op,
1407 f->lsm_rule,
1408 NULL);
1409 }
1410 break;
1411 }
1412
1413 if (!result)
1414 return 0;
1415 }
1416 switch (rule->action) {
1417 case AUDIT_NEVER: *state = AUDIT_DISABLED; break;
1418 case AUDIT_ALWAYS: *state = AUDIT_RECORD_CONTEXT; break;
1419 }
1420 return 1;
1421 }
1422
1423 int audit_filter_user(int type)
1424 {
1425 enum audit_state state = AUDIT_DISABLED;
1426 struct audit_entry *e;
1427 int ret = 1;
1428
1429 rcu_read_lock();
1430 list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_USER], list) {
1431 if (audit_filter_user_rules(&e->rule, type, &state)) {
1432 if (state == AUDIT_DISABLED)
1433 ret = 0;
1434 break;
1435 }
1436 }
1437 rcu_read_unlock();
1438
1439 return ret; /* Audit by default */
1440 }
1441
1442 int audit_filter_type(int type)
1443 {
1444 struct audit_entry *e;
1445 int result = 0;
1446
1447 rcu_read_lock();
1448 if (list_empty(&audit_filter_list[AUDIT_FILTER_TYPE]))
1449 goto unlock_and_return;
1450
1451 list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_TYPE],
1452 list) {
1453 int i;
1454 for (i = 0; i < e->rule.field_count; i++) {
1455 struct audit_field *f = &e->rule.fields[i];
1456 if (f->type == AUDIT_MSGTYPE) {
1457 result = audit_comparator(type, f->op, f->val);
1458 if (!result)
1459 break;
1460 }
1461 }
1462 if (result)
1463 goto unlock_and_return;
1464 }
1465 unlock_and_return:
1466 rcu_read_unlock();
1467 return result;
1468 }
1469
1470 static int update_lsm_rule(struct audit_krule *r)
1471 {
1472 struct audit_entry *entry = container_of(r, struct audit_entry, rule);
1473 struct audit_entry *nentry;
1474 int err = 0;
1475
1476 if (!security_audit_rule_known(r))
1477 return 0;
1478
1479 nentry = audit_dupe_rule(r);
1480 if (IS_ERR(nentry)) {
1481 /* save the first error encountered for the
1482 * return value */
1483 err = PTR_ERR(nentry);
1484 audit_panic("error updating LSM filters");
1485 if (r->watch)
1486 list_del(&r->rlist);
1487 list_del_rcu(&entry->list);
1488 list_del(&r->list);
1489 } else {
1490 if (r->watch || r->tree)
1491 list_replace_init(&r->rlist, &nentry->rule.rlist);
1492 list_replace_rcu(&entry->list, &nentry->list);
1493 list_replace(&r->list, &nentry->rule.list);
1494 }
1495 call_rcu(&entry->rcu, audit_free_rule_rcu);
1496
1497 return err;
1498 }
1499
1500 /* This function will re-initialize the lsm_rule field of all applicable rules.
1501 * It will traverse the filter lists serarching for rules that contain LSM
1502 * specific filter fields. When such a rule is found, it is copied, the
1503 * LSM field is re-initialized, and the old rule is replaced with the
1504 * updated rule. */
1505 int audit_update_lsm_rules(void)
1506 {
1507 struct audit_krule *r, *n;
1508 int i, err = 0;
1509
1510 /* audit_filter_mutex synchronizes the writers */
1511 mutex_lock(&audit_filter_mutex);
1512
1513 for (i = 0; i < AUDIT_NR_FILTERS; i++) {
1514 list_for_each_entry_safe(r, n, &audit_rules_list[i], list) {
1515 int res = update_lsm_rule(r);
1516 if (!err)
1517 err = res;
1518 }
1519 }
1520 mutex_unlock(&audit_filter_mutex);
1521
1522 return err;
1523 }
Linux kernel - Deliverables
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