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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
23
24 #include <linux/kernel.h>
25 #include <linux/audit.h>
26 #include <linux/kthread.h>
27 #include <linux/mutex.h>
28 #include <linux/fs.h>
29 #include <linux/namei.h>
30 #include <linux/netlink.h>
31 #include <linux/sched.h>
32 #include <linux/slab.h>
33 #include <linux/security.h>
34 #include <net/net_namespace.h>
35 #include <net/sock.h>
36 #include "audit.h"
37
38 /*
39 * Locking model:
40 *
41 * audit_filter_mutex:
42 * Synchronizes writes and blocking reads of audit's filterlist
43 * data. Rcu is used to traverse the filterlist and access
44 * contents of structs audit_entry, audit_watch and opaque
45 * LSM rules during filtering. If modified, these structures
46 * must be copied and replace their counterparts in the filterlist.
47 * An audit_parent struct is not accessed during filtering, so may
48 * be written directly provided audit_filter_mutex is held.
49 */
50
51 /* Audit filter lists, defined in <linux/audit.h> */
52 struct list_head audit_filter_list[AUDIT_NR_FILTERS] = {
53 LIST_HEAD_INIT(audit_filter_list[0]),
54 LIST_HEAD_INIT(audit_filter_list[1]),
55 LIST_HEAD_INIT(audit_filter_list[2]),
56 LIST_HEAD_INIT(audit_filter_list[3]),
57 LIST_HEAD_INIT(audit_filter_list[4]),
58 LIST_HEAD_INIT(audit_filter_list[5]),
59 #if AUDIT_NR_FILTERS != 6
60 #error Fix audit_filter_list initialiser
61 #endif
62 };
63 static struct list_head audit_rules_list[AUDIT_NR_FILTERS] = {
64 LIST_HEAD_INIT(audit_rules_list[0]),
65 LIST_HEAD_INIT(audit_rules_list[1]),
66 LIST_HEAD_INIT(audit_rules_list[2]),
67 LIST_HEAD_INIT(audit_rules_list[3]),
68 LIST_HEAD_INIT(audit_rules_list[4]),
69 LIST_HEAD_INIT(audit_rules_list[5]),
70 };
71
72 DEFINE_MUTEX(audit_filter_mutex);
73
audit_free_lsm_field(struct audit_field * f)74 static void audit_free_lsm_field(struct audit_field *f)
75 {
76 switch (f->type) {
77 case AUDIT_SUBJ_USER:
78 case AUDIT_SUBJ_ROLE:
79 case AUDIT_SUBJ_TYPE:
80 case AUDIT_SUBJ_SEN:
81 case AUDIT_SUBJ_CLR:
82 case AUDIT_OBJ_USER:
83 case AUDIT_OBJ_ROLE:
84 case AUDIT_OBJ_TYPE:
85 case AUDIT_OBJ_LEV_LOW:
86 case AUDIT_OBJ_LEV_HIGH:
87 kfree(f->lsm_str);
88 security_audit_rule_free(f->lsm_rule);
89 }
90 }
91
audit_free_rule(struct audit_entry * e)92 static inline void audit_free_rule(struct audit_entry *e)
93 {
94 int i;
95 struct audit_krule *erule = &e->rule;
96
97 /* some rules don't have associated watches */
98 if (erule->watch)
99 audit_put_watch(erule->watch);
100 if (erule->fields)
101 for (i = 0; i < erule->field_count; i++)
102 audit_free_lsm_field(&erule->fields[i]);
103 kfree(erule->fields);
104 kfree(erule->filterkey);
105 kfree(e);
106 }
107
audit_free_rule_rcu(struct rcu_head * head)108 void audit_free_rule_rcu(struct rcu_head *head)
109 {
110 struct audit_entry *e = container_of(head, struct audit_entry, rcu);
111 audit_free_rule(e);
112 }
113
114 /* Initialize an audit filterlist entry. */
audit_init_entry(u32 field_count)115 static inline struct audit_entry *audit_init_entry(u32 field_count)
116 {
117 struct audit_entry *entry;
118 struct audit_field *fields;
119
120 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
121 if (unlikely(!entry))
122 return NULL;
123
124 fields = kcalloc(field_count, sizeof(*fields), GFP_KERNEL);
125 if (unlikely(!fields)) {
126 kfree(entry);
127 return NULL;
128 }
129 entry->rule.fields = fields;
130
131 return entry;
132 }
133
134 /* Unpack a filter field's string representation from user-space
135 * buffer. */
audit_unpack_string(void ** bufp,size_t * remain,size_t len)136 char *audit_unpack_string(void **bufp, size_t *remain, size_t len)
137 {
138 char *str;
139
140 if (!*bufp || (len == 0) || (len > *remain))
141 return ERR_PTR(-EINVAL);
142
143 /* Of the currently implemented string fields, PATH_MAX
144 * defines the longest valid length.
145 */
146 if (len > PATH_MAX)
147 return ERR_PTR(-ENAMETOOLONG);
148
149 str = kmalloc(len + 1, GFP_KERNEL);
150 if (unlikely(!str))
151 return ERR_PTR(-ENOMEM);
152
153 memcpy(str, *bufp, len);
154 str[len] = 0;
155 *bufp += len;
156 *remain -= len;
157
158 return str;
159 }
160
161 /* Translate an inode field to kernel respresentation. */
audit_to_inode(struct audit_krule * krule,struct audit_field * f)162 static inline int audit_to_inode(struct audit_krule *krule,
163 struct audit_field *f)
164 {
165 if (krule->listnr != AUDIT_FILTER_EXIT ||
166 krule->inode_f || krule->watch || krule->tree ||
167 (f->op != Audit_equal && f->op != Audit_not_equal))
168 return -EINVAL;
169
170 krule->inode_f = f;
171 return 0;
172 }
173
174 static __u32 *classes[AUDIT_SYSCALL_CLASSES];
175
audit_register_class(int class,unsigned * list)176 int __init audit_register_class(int class, unsigned *list)
177 {
178 __u32 *p = kcalloc(AUDIT_BITMASK_SIZE, sizeof(__u32), GFP_KERNEL);
179 if (!p)
180 return -ENOMEM;
181 while (*list != ~0U) {
182 unsigned n = *list++;
183 if (n >= AUDIT_BITMASK_SIZE * 32 - AUDIT_SYSCALL_CLASSES) {
184 kfree(p);
185 return -EINVAL;
186 }
187 p[AUDIT_WORD(n)] |= AUDIT_BIT(n);
188 }
189 if (class >= AUDIT_SYSCALL_CLASSES || classes[class]) {
190 kfree(p);
191 return -EINVAL;
192 }
193 classes[class] = p;
194 return 0;
195 }
196
audit_match_class(int class,unsigned syscall)197 int audit_match_class(int class, unsigned syscall)
198 {
199 if (unlikely(syscall >= AUDIT_BITMASK_SIZE * 32))
200 return 0;
201 if (unlikely(class >= AUDIT_SYSCALL_CLASSES || !classes[class]))
202 return 0;
203 return classes[class][AUDIT_WORD(syscall)] & AUDIT_BIT(syscall);
204 }
205
206 #ifdef CONFIG_AUDITSYSCALL
audit_match_class_bits(int class,u32 * mask)207 static inline int audit_match_class_bits(int class, u32 *mask)
208 {
209 int i;
210
211 if (classes[class]) {
212 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
213 if (mask[i] & classes[class][i])
214 return 0;
215 }
216 return 1;
217 }
218
audit_match_signal(struct audit_entry * entry)219 static int audit_match_signal(struct audit_entry *entry)
220 {
221 struct audit_field *arch = entry->rule.arch_f;
222
223 if (!arch) {
224 /* When arch is unspecified, we must check both masks on biarch
225 * as syscall number alone is ambiguous. */
226 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
227 entry->rule.mask) &&
228 audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
229 entry->rule.mask));
230 }
231
232 switch(audit_classify_arch(arch->val)) {
233 case 0: /* native */
234 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
235 entry->rule.mask));
236 case 1: /* 32bit on biarch */
237 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
238 entry->rule.mask));
239 default:
240 return 1;
241 }
242 }
243 #endif
244
245 /* Common user-space to kernel rule translation. */
audit_to_entry_common(struct audit_rule_data * rule)246 static inline struct audit_entry *audit_to_entry_common(struct audit_rule_data *rule)
247 {
248 unsigned listnr;
249 struct audit_entry *entry;
250 int i, err;
251
252 err = -EINVAL;
253 listnr = rule->flags & ~AUDIT_FILTER_PREPEND;
254 switch(listnr) {
255 default:
256 goto exit_err;
257 #ifdef CONFIG_AUDITSYSCALL
258 case AUDIT_FILTER_ENTRY:
259 if (rule->action == AUDIT_ALWAYS)
260 goto exit_err;
261 case AUDIT_FILTER_EXIT:
262 case AUDIT_FILTER_TASK:
263 #endif
264 case AUDIT_FILTER_USER:
265 case AUDIT_FILTER_TYPE:
266 ;
267 }
268 if (unlikely(rule->action == AUDIT_POSSIBLE)) {
269 pr_err("AUDIT_POSSIBLE is deprecated\n");
270 goto exit_err;
271 }
272 if (rule->action != AUDIT_NEVER && rule->action != AUDIT_ALWAYS)
273 goto exit_err;
274 if (rule->field_count > AUDIT_MAX_FIELDS)
275 goto exit_err;
276
277 err = -ENOMEM;
278 entry = audit_init_entry(rule->field_count);
279 if (!entry)
280 goto exit_err;
281
282 entry->rule.flags = rule->flags & AUDIT_FILTER_PREPEND;
283 entry->rule.listnr = listnr;
284 entry->rule.action = rule->action;
285 entry->rule.field_count = rule->field_count;
286
287 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
288 entry->rule.mask[i] = rule->mask[i];
289
290 for (i = 0; i < AUDIT_SYSCALL_CLASSES; i++) {
291 int bit = AUDIT_BITMASK_SIZE * 32 - i - 1;
292 __u32 *p = &entry->rule.mask[AUDIT_WORD(bit)];
293 __u32 *class;
294
295 if (!(*p & AUDIT_BIT(bit)))
296 continue;
297 *p &= ~AUDIT_BIT(bit);
298 class = classes[i];
299 if (class) {
300 int j;
301 for (j = 0; j < AUDIT_BITMASK_SIZE; j++)
302 entry->rule.mask[j] |= class[j];
303 }
304 }
305
306 return entry;
307
308 exit_err:
309 return ERR_PTR(err);
310 }
311
312 static u32 audit_ops[] =
313 {
314 [Audit_equal] = AUDIT_EQUAL,
315 [Audit_not_equal] = AUDIT_NOT_EQUAL,
316 [Audit_bitmask] = AUDIT_BIT_MASK,
317 [Audit_bittest] = AUDIT_BIT_TEST,
318 [Audit_lt] = AUDIT_LESS_THAN,
319 [Audit_gt] = AUDIT_GREATER_THAN,
320 [Audit_le] = AUDIT_LESS_THAN_OR_EQUAL,
321 [Audit_ge] = AUDIT_GREATER_THAN_OR_EQUAL,
322 };
323
audit_to_op(u32 op)324 static u32 audit_to_op(u32 op)
325 {
326 u32 n;
327 for (n = Audit_equal; n < Audit_bad && audit_ops[n] != op; n++)
328 ;
329 return n;
330 }
331
332 /* check if an audit field is valid */
audit_field_valid(struct audit_entry * entry,struct audit_field * f)333 static int audit_field_valid(struct audit_entry *entry, struct audit_field *f)
334 {
335 switch(f->type) {
336 case AUDIT_MSGTYPE:
337 if (entry->rule.listnr != AUDIT_FILTER_TYPE &&
338 entry->rule.listnr != AUDIT_FILTER_USER)
339 return -EINVAL;
340 break;
341 };
342
343 switch(f->type) {
344 default:
345 return -EINVAL;
346 case AUDIT_UID:
347 case AUDIT_EUID:
348 case AUDIT_SUID:
349 case AUDIT_FSUID:
350 case AUDIT_LOGINUID:
351 case AUDIT_OBJ_UID:
352 case AUDIT_GID:
353 case AUDIT_EGID:
354 case AUDIT_SGID:
355 case AUDIT_FSGID:
356 case AUDIT_OBJ_GID:
357 case AUDIT_PID:
358 case AUDIT_PERS:
359 case AUDIT_MSGTYPE:
360 case AUDIT_PPID:
361 case AUDIT_DEVMAJOR:
362 case AUDIT_DEVMINOR:
363 case AUDIT_EXIT:
364 case AUDIT_SUCCESS:
365 case AUDIT_INODE:
366 /* bit ops are only useful on syscall args */
367 if (f->op == Audit_bitmask || f->op == Audit_bittest)
368 return -EINVAL;
369 break;
370 case AUDIT_ARG0:
371 case AUDIT_ARG1:
372 case AUDIT_ARG2:
373 case AUDIT_ARG3:
374 case AUDIT_SUBJ_USER:
375 case AUDIT_SUBJ_ROLE:
376 case AUDIT_SUBJ_TYPE:
377 case AUDIT_SUBJ_SEN:
378 case AUDIT_SUBJ_CLR:
379 case AUDIT_OBJ_USER:
380 case AUDIT_OBJ_ROLE:
381 case AUDIT_OBJ_TYPE:
382 case AUDIT_OBJ_LEV_LOW:
383 case AUDIT_OBJ_LEV_HIGH:
384 case AUDIT_WATCH:
385 case AUDIT_DIR:
386 case AUDIT_FILTERKEY:
387 break;
388 case AUDIT_LOGINUID_SET:
389 if ((f->val != 0) && (f->val != 1))
390 return -EINVAL;
391 /* FALL THROUGH */
392 case AUDIT_ARCH:
393 if (f->op != Audit_not_equal && f->op != Audit_equal)
394 return -EINVAL;
395 break;
396 case AUDIT_PERM:
397 if (f->val & ~15)
398 return -EINVAL;
399 break;
400 case AUDIT_FILETYPE:
401 if (f->val & ~S_IFMT)
402 return -EINVAL;
403 break;
404 case AUDIT_FIELD_COMPARE:
405 if (f->val > AUDIT_MAX_FIELD_COMPARE)
406 return -EINVAL;
407 break;
408 case AUDIT_EXE:
409 if (f->op != Audit_not_equal && f->op != Audit_equal)
410 return -EINVAL;
411 if (entry->rule.listnr != AUDIT_FILTER_EXIT)
412 return -EINVAL;
413 break;
414 };
415 return 0;
416 }
417
418 /* Translate struct audit_rule_data to kernel's rule respresentation. */
audit_data_to_entry(struct audit_rule_data * data,size_t datasz)419 static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
420 size_t datasz)
421 {
422 int err = 0;
423 struct audit_entry *entry;
424 void *bufp;
425 size_t remain = datasz - sizeof(struct audit_rule_data);
426 int i;
427 char *str;
428 struct audit_fsnotify_mark *audit_mark;
429
430 entry = audit_to_entry_common(data);
431 if (IS_ERR(entry))
432 goto exit_nofree;
433
434 bufp = data->buf;
435 for (i = 0; i < data->field_count; i++) {
436 struct audit_field *f = &entry->rule.fields[i];
437 u32 f_val;
438
439 err = -EINVAL;
440
441 f->op = audit_to_op(data->fieldflags[i]);
442 if (f->op == Audit_bad)
443 goto exit_free;
444
445 f->type = data->fields[i];
446 f_val = data->values[i];
447
448 /* Support legacy tests for a valid loginuid */
449 if ((f->type == AUDIT_LOGINUID) && (f_val == AUDIT_UID_UNSET)) {
450 f->type = AUDIT_LOGINUID_SET;
451 f_val = 0;
452 entry->rule.pflags |= AUDIT_LOGINUID_LEGACY;
453 }
454
455 err = audit_field_valid(entry, f);
456 if (err)
457 goto exit_free;
458
459 err = -EINVAL;
460 switch (f->type) {
461 case AUDIT_LOGINUID:
462 case AUDIT_UID:
463 case AUDIT_EUID:
464 case AUDIT_SUID:
465 case AUDIT_FSUID:
466 case AUDIT_OBJ_UID:
467 f->uid = make_kuid(current_user_ns(), f_val);
468 if (!uid_valid(f->uid))
469 goto exit_free;
470 break;
471 case AUDIT_GID:
472 case AUDIT_EGID:
473 case AUDIT_SGID:
474 case AUDIT_FSGID:
475 case AUDIT_OBJ_GID:
476 f->gid = make_kgid(current_user_ns(), f_val);
477 if (!gid_valid(f->gid))
478 goto exit_free;
479 break;
480 case AUDIT_ARCH:
481 f->val = f_val;
482 entry->rule.arch_f = f;
483 break;
484 case AUDIT_SUBJ_USER:
485 case AUDIT_SUBJ_ROLE:
486 case AUDIT_SUBJ_TYPE:
487 case AUDIT_SUBJ_SEN:
488 case AUDIT_SUBJ_CLR:
489 case AUDIT_OBJ_USER:
490 case AUDIT_OBJ_ROLE:
491 case AUDIT_OBJ_TYPE:
492 case AUDIT_OBJ_LEV_LOW:
493 case AUDIT_OBJ_LEV_HIGH:
494 str = audit_unpack_string(&bufp, &remain, f_val);
495 if (IS_ERR(str)) {
496 err = PTR_ERR(str);
497 goto exit_free;
498 }
499 entry->rule.buflen += f_val;
500 f->lsm_str = str;
501 err = security_audit_rule_init(f->type, f->op, str,
502 (void **)&f->lsm_rule);
503 /* Keep currently invalid fields around in case they
504 * become valid after a policy reload. */
505 if (err == -EINVAL) {
506 pr_warn("audit rule for LSM \'%s\' is invalid\n",
507 str);
508 err = 0;
509 } else if (err)
510 goto exit_free;
511 break;
512 case AUDIT_WATCH:
513 str = audit_unpack_string(&bufp, &remain, f_val);
514 if (IS_ERR(str)) {
515 err = PTR_ERR(str);
516 goto exit_free;
517 }
518 err = audit_to_watch(&entry->rule, str, f_val, f->op);
519 if (err) {
520 kfree(str);
521 goto exit_free;
522 }
523 entry->rule.buflen += f_val;
524 break;
525 case AUDIT_DIR:
526 str = audit_unpack_string(&bufp, &remain, f_val);
527 if (IS_ERR(str)) {
528 err = PTR_ERR(str);
529 goto exit_free;
530 }
531 err = audit_make_tree(&entry->rule, str, f->op);
532 kfree(str);
533 if (err)
534 goto exit_free;
535 entry->rule.buflen += f_val;
536 break;
537 case AUDIT_INODE:
538 f->val = f_val;
539 err = audit_to_inode(&entry->rule, f);
540 if (err)
541 goto exit_free;
542 break;
543 case AUDIT_FILTERKEY:
544 if (entry->rule.filterkey || f_val > AUDIT_MAX_KEY_LEN)
545 goto exit_free;
546 str = audit_unpack_string(&bufp, &remain, f_val);
547 if (IS_ERR(str)) {
548 err = PTR_ERR(str);
549 goto exit_free;
550 }
551 entry->rule.buflen += f_val;
552 entry->rule.filterkey = str;
553 break;
554 case AUDIT_EXE:
555 if (entry->rule.exe || f_val > PATH_MAX)
556 goto exit_free;
557 str = audit_unpack_string(&bufp, &remain, f_val);
558 if (IS_ERR(str)) {
559 err = PTR_ERR(str);
560 goto exit_free;
561 }
562 audit_mark = audit_alloc_mark(&entry->rule, str, f_val);
563 if (IS_ERR(audit_mark)) {
564 kfree(str);
565 err = PTR_ERR(audit_mark);
566 goto exit_free;
567 }
568 entry->rule.buflen += f_val;
569 entry->rule.exe = audit_mark;
570 break;
571 default:
572 f->val = f_val;
573 break;
574 }
575 }
576
577 if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal)
578 entry->rule.inode_f = NULL;
579
580 exit_nofree:
581 return entry;
582
583 exit_free:
584 if (entry->rule.tree)
585 audit_put_tree(entry->rule.tree); /* that's the temporary one */
586 if (entry->rule.exe)
587 audit_remove_mark(entry->rule.exe); /* that's the template one */
588 audit_free_rule(entry);
589 return ERR_PTR(err);
590 }
591
592 /* Pack a filter field's string representation into data block. */
audit_pack_string(void ** bufp,const char * str)593 static inline size_t audit_pack_string(void **bufp, const char *str)
594 {
595 size_t len = strlen(str);
596
597 memcpy(*bufp, str, len);
598 *bufp += len;
599
600 return len;
601 }
602
603 /* Translate kernel rule respresentation to struct audit_rule_data. */
audit_krule_to_data(struct audit_krule * krule)604 static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule)
605 {
606 struct audit_rule_data *data;
607 void *bufp;
608 int i;
609
610 data = kmalloc(sizeof(*data) + krule->buflen, GFP_KERNEL);
611 if (unlikely(!data))
612 return NULL;
613 memset(data, 0, sizeof(*data));
614
615 data->flags = krule->flags | krule->listnr;
616 data->action = krule->action;
617 data->field_count = krule->field_count;
618 bufp = data->buf;
619 for (i = 0; i < data->field_count; i++) {
620 struct audit_field *f = &krule->fields[i];
621
622 data->fields[i] = f->type;
623 data->fieldflags[i] = audit_ops[f->op];
624 switch(f->type) {
625 case AUDIT_SUBJ_USER:
626 case AUDIT_SUBJ_ROLE:
627 case AUDIT_SUBJ_TYPE:
628 case AUDIT_SUBJ_SEN:
629 case AUDIT_SUBJ_CLR:
630 case AUDIT_OBJ_USER:
631 case AUDIT_OBJ_ROLE:
632 case AUDIT_OBJ_TYPE:
633 case AUDIT_OBJ_LEV_LOW:
634 case AUDIT_OBJ_LEV_HIGH:
635 data->buflen += data->values[i] =
636 audit_pack_string(&bufp, f->lsm_str);
637 break;
638 case AUDIT_WATCH:
639 data->buflen += data->values[i] =
640 audit_pack_string(&bufp,
641 audit_watch_path(krule->watch));
642 break;
643 case AUDIT_DIR:
644 data->buflen += data->values[i] =
645 audit_pack_string(&bufp,
646 audit_tree_path(krule->tree));
647 break;
648 case AUDIT_FILTERKEY:
649 data->buflen += data->values[i] =
650 audit_pack_string(&bufp, krule->filterkey);
651 break;
652 case AUDIT_EXE:
653 data->buflen += data->values[i] =
654 audit_pack_string(&bufp, audit_mark_path(krule->exe));
655 break;
656 case AUDIT_LOGINUID_SET:
657 if (krule->pflags & AUDIT_LOGINUID_LEGACY && !f->val) {
658 data->fields[i] = AUDIT_LOGINUID;
659 data->values[i] = AUDIT_UID_UNSET;
660 break;
661 }
662 /* fallthrough if set */
663 default:
664 data->values[i] = f->val;
665 }
666 }
667 for (i = 0; i < AUDIT_BITMASK_SIZE; i++) data->mask[i] = krule->mask[i];
668
669 return data;
670 }
671
672 /* Compare two rules in kernel format. Considered success if rules
673 * don't match. */
audit_compare_rule(struct audit_krule * a,struct audit_krule * b)674 static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
675 {
676 int i;
677
678 if (a->flags != b->flags ||
679 a->pflags != b->pflags ||
680 a->listnr != b->listnr ||
681 a->action != b->action ||
682 a->field_count != b->field_count)
683 return 1;
684
685 for (i = 0; i < a->field_count; i++) {
686 if (a->fields[i].type != b->fields[i].type ||
687 a->fields[i].op != b->fields[i].op)
688 return 1;
689
690 switch(a->fields[i].type) {
691 case AUDIT_SUBJ_USER:
692 case AUDIT_SUBJ_ROLE:
693 case AUDIT_SUBJ_TYPE:
694 case AUDIT_SUBJ_SEN:
695 case AUDIT_SUBJ_CLR:
696 case AUDIT_OBJ_USER:
697 case AUDIT_OBJ_ROLE:
698 case AUDIT_OBJ_TYPE:
699 case AUDIT_OBJ_LEV_LOW:
700 case AUDIT_OBJ_LEV_HIGH:
701 if (strcmp(a->fields[i].lsm_str, b->fields[i].lsm_str))
702 return 1;
703 break;
704 case AUDIT_WATCH:
705 if (strcmp(audit_watch_path(a->watch),
706 audit_watch_path(b->watch)))
707 return 1;
708 break;
709 case AUDIT_DIR:
710 if (strcmp(audit_tree_path(a->tree),
711 audit_tree_path(b->tree)))
712 return 1;
713 break;
714 case AUDIT_FILTERKEY:
715 /* both filterkeys exist based on above type compare */
716 if (strcmp(a->filterkey, b->filterkey))
717 return 1;
718 break;
719 case AUDIT_EXE:
720 /* both paths exist based on above type compare */
721 if (strcmp(audit_mark_path(a->exe),
722 audit_mark_path(b->exe)))
723 return 1;
724 break;
725 case AUDIT_UID:
726 case AUDIT_EUID:
727 case AUDIT_SUID:
728 case AUDIT_FSUID:
729 case AUDIT_LOGINUID:
730 case AUDIT_OBJ_UID:
731 if (!uid_eq(a->fields[i].uid, b->fields[i].uid))
732 return 1;
733 break;
734 case AUDIT_GID:
735 case AUDIT_EGID:
736 case AUDIT_SGID:
737 case AUDIT_FSGID:
738 case AUDIT_OBJ_GID:
739 if (!gid_eq(a->fields[i].gid, b->fields[i].gid))
740 return 1;
741 break;
742 default:
743 if (a->fields[i].val != b->fields[i].val)
744 return 1;
745 }
746 }
747
748 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
749 if (a->mask[i] != b->mask[i])
750 return 1;
751
752 return 0;
753 }
754
755 /* Duplicate LSM field information. The lsm_rule is opaque, so must be
756 * re-initialized. */
audit_dupe_lsm_field(struct audit_field * df,struct audit_field * sf)757 static inline int audit_dupe_lsm_field(struct audit_field *df,
758 struct audit_field *sf)
759 {
760 int ret = 0;
761 char *lsm_str;
762
763 /* our own copy of lsm_str */
764 lsm_str = kstrdup(sf->lsm_str, GFP_KERNEL);
765 if (unlikely(!lsm_str))
766 return -ENOMEM;
767 df->lsm_str = lsm_str;
768
769 /* our own (refreshed) copy of lsm_rule */
770 ret = security_audit_rule_init(df->type, df->op, df->lsm_str,
771 (void **)&df->lsm_rule);
772 /* Keep currently invalid fields around in case they
773 * become valid after a policy reload. */
774 if (ret == -EINVAL) {
775 pr_warn("audit rule for LSM \'%s\' is invalid\n",
776 df->lsm_str);
777 ret = 0;
778 }
779
780 return ret;
781 }
782
783 /* Duplicate an audit rule. This will be a deep copy with the exception
784 * of the watch - that pointer is carried over. The LSM specific fields
785 * will be updated in the copy. The point is to be able to replace the old
786 * rule with the new rule in the filterlist, then free the old rule.
787 * The rlist element is undefined; list manipulations are handled apart from
788 * the initial copy. */
audit_dupe_rule(struct audit_krule * old)789 struct audit_entry *audit_dupe_rule(struct audit_krule *old)
790 {
791 u32 fcount = old->field_count;
792 struct audit_entry *entry;
793 struct audit_krule *new;
794 char *fk;
795 int i, err = 0;
796
797 entry = audit_init_entry(fcount);
798 if (unlikely(!entry))
799 return ERR_PTR(-ENOMEM);
800
801 new = &entry->rule;
802 new->flags = old->flags;
803 new->pflags = old->pflags;
804 new->listnr = old->listnr;
805 new->action = old->action;
806 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
807 new->mask[i] = old->mask[i];
808 new->prio = old->prio;
809 new->buflen = old->buflen;
810 new->inode_f = old->inode_f;
811 new->field_count = old->field_count;
812
813 /*
814 * note that we are OK with not refcounting here; audit_match_tree()
815 * never dereferences tree and we can't get false positives there
816 * since we'd have to have rule gone from the list *and* removed
817 * before the chunks found by lookup had been allocated, i.e. before
818 * the beginning of list scan.
819 */
820 new->tree = old->tree;
821 memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount);
822
823 /* deep copy this information, updating the lsm_rule fields, because
824 * the originals will all be freed when the old rule is freed. */
825 for (i = 0; i < fcount; i++) {
826 switch (new->fields[i].type) {
827 case AUDIT_SUBJ_USER:
828 case AUDIT_SUBJ_ROLE:
829 case AUDIT_SUBJ_TYPE:
830 case AUDIT_SUBJ_SEN:
831 case AUDIT_SUBJ_CLR:
832 case AUDIT_OBJ_USER:
833 case AUDIT_OBJ_ROLE:
834 case AUDIT_OBJ_TYPE:
835 case AUDIT_OBJ_LEV_LOW:
836 case AUDIT_OBJ_LEV_HIGH:
837 err = audit_dupe_lsm_field(&new->fields[i],
838 &old->fields[i]);
839 break;
840 case AUDIT_FILTERKEY:
841 fk = kstrdup(old->filterkey, GFP_KERNEL);
842 if (unlikely(!fk))
843 err = -ENOMEM;
844 else
845 new->filterkey = fk;
846 break;
847 case AUDIT_EXE:
848 err = audit_dupe_exe(new, old);
849 break;
850 }
851 if (err) {
852 if (new->exe)
853 audit_remove_mark(new->exe);
854 audit_free_rule(entry);
855 return ERR_PTR(err);
856 }
857 }
858
859 if (old->watch) {
860 audit_get_watch(old->watch);
861 new->watch = old->watch;
862 }
863
864 return entry;
865 }
866
867 /* Find an existing audit rule.
868 * Caller must hold audit_filter_mutex to prevent stale rule data. */
audit_find_rule(struct audit_entry * entry,struct list_head ** p)869 static struct audit_entry *audit_find_rule(struct audit_entry *entry,
870 struct list_head **p)
871 {
872 struct audit_entry *e, *found = NULL;
873 struct list_head *list;
874 int h;
875
876 if (entry->rule.inode_f) {
877 h = audit_hash_ino(entry->rule.inode_f->val);
878 *p = list = &audit_inode_hash[h];
879 } else if (entry->rule.watch) {
880 /* we don't know the inode number, so must walk entire hash */
881 for (h = 0; h < AUDIT_INODE_BUCKETS; h++) {
882 list = &audit_inode_hash[h];
883 list_for_each_entry(e, list, list)
884 if (!audit_compare_rule(&entry->rule, &e->rule)) {
885 found = e;
886 goto out;
887 }
888 }
889 goto out;
890 } else {
891 *p = list = &audit_filter_list[entry->rule.listnr];
892 }
893
894 list_for_each_entry(e, list, list)
895 if (!audit_compare_rule(&entry->rule, &e->rule)) {
896 found = e;
897 goto out;
898 }
899
900 out:
901 return found;
902 }
903
904 static u64 prio_low = ~0ULL/2;
905 static u64 prio_high = ~0ULL/2 - 1;
906
907 /* Add rule to given filterlist if not a duplicate. */
audit_add_rule(struct audit_entry * entry)908 static inline int audit_add_rule(struct audit_entry *entry)
909 {
910 struct audit_entry *e;
911 struct audit_watch *watch = entry->rule.watch;
912 struct audit_tree *tree = entry->rule.tree;
913 struct list_head *list;
914 int err = 0;
915 #ifdef CONFIG_AUDITSYSCALL
916 int dont_count = 0;
917
918 /* If either of these, don't count towards total */
919 if (entry->rule.listnr == AUDIT_FILTER_USER ||
920 entry->rule.listnr == AUDIT_FILTER_TYPE)
921 dont_count = 1;
922 #endif
923
924 mutex_lock(&audit_filter_mutex);
925 e = audit_find_rule(entry, &list);
926 if (e) {
927 mutex_unlock(&audit_filter_mutex);
928 err = -EEXIST;
929 /* normally audit_add_tree_rule() will free it on failure */
930 if (tree)
931 audit_put_tree(tree);
932 return err;
933 }
934
935 if (watch) {
936 /* audit_filter_mutex is dropped and re-taken during this call */
937 err = audit_add_watch(&entry->rule, &list);
938 if (err) {
939 mutex_unlock(&audit_filter_mutex);
940 /*
941 * normally audit_add_tree_rule() will free it
942 * on failure
943 */
944 if (tree)
945 audit_put_tree(tree);
946 return err;
947 }
948 }
949 if (tree) {
950 err = audit_add_tree_rule(&entry->rule);
951 if (err) {
952 mutex_unlock(&audit_filter_mutex);
953 return err;
954 }
955 }
956
957 entry->rule.prio = ~0ULL;
958 if (entry->rule.listnr == AUDIT_FILTER_EXIT) {
959 if (entry->rule.flags & AUDIT_FILTER_PREPEND)
960 entry->rule.prio = ++prio_high;
961 else
962 entry->rule.prio = --prio_low;
963 }
964
965 if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
966 list_add(&entry->rule.list,
967 &audit_rules_list[entry->rule.listnr]);
968 list_add_rcu(&entry->list, list);
969 entry->rule.flags &= ~AUDIT_FILTER_PREPEND;
970 } else {
971 list_add_tail(&entry->rule.list,
972 &audit_rules_list[entry->rule.listnr]);
973 list_add_tail_rcu(&entry->list, list);
974 }
975 #ifdef CONFIG_AUDITSYSCALL
976 if (!dont_count)
977 audit_n_rules++;
978
979 if (!audit_match_signal(entry))
980 audit_signals++;
981 #endif
982 mutex_unlock(&audit_filter_mutex);
983
984 return err;
985 }
986
987 /* Remove an existing rule from filterlist. */
audit_del_rule(struct audit_entry * entry)988 int audit_del_rule(struct audit_entry *entry)
989 {
990 struct audit_entry *e;
991 struct audit_tree *tree = entry->rule.tree;
992 struct list_head *list;
993 int ret = 0;
994 #ifdef CONFIG_AUDITSYSCALL
995 int dont_count = 0;
996
997 /* If either of these, don't count towards total */
998 if (entry->rule.listnr == AUDIT_FILTER_USER ||
999 entry->rule.listnr == AUDIT_FILTER_TYPE)
1000 dont_count = 1;
1001 #endif
1002
1003 mutex_lock(&audit_filter_mutex);
1004 e = audit_find_rule(entry, &list);
1005 if (!e) {
1006 ret = -ENOENT;
1007 goto out;
1008 }
1009
1010 if (e->rule.watch)
1011 audit_remove_watch_rule(&e->rule);
1012
1013 if (e->rule.tree)
1014 audit_remove_tree_rule(&e->rule);
1015
1016 if (e->rule.exe)
1017 audit_remove_mark_rule(&e->rule);
1018
1019 #ifdef CONFIG_AUDITSYSCALL
1020 if (!dont_count)
1021 audit_n_rules--;
1022
1023 if (!audit_match_signal(entry))
1024 audit_signals--;
1025 #endif
1026
1027 list_del_rcu(&e->list);
1028 list_del(&e->rule.list);
1029 call_rcu(&e->rcu, audit_free_rule_rcu);
1030
1031 out:
1032 mutex_unlock(&audit_filter_mutex);
1033
1034 if (tree)
1035 audit_put_tree(tree); /* that's the temporary one */
1036
1037 return ret;
1038 }
1039
1040 /* List rules using struct audit_rule_data. */
audit_list_rules(__u32 portid,int seq,struct sk_buff_head * q)1041 static void audit_list_rules(__u32 portid, int seq, struct sk_buff_head *q)
1042 {
1043 struct sk_buff *skb;
1044 struct audit_krule *r;
1045 int i;
1046
1047 /* This is a blocking read, so use audit_filter_mutex instead of rcu
1048 * iterator to sync with list writers. */
1049 for (i=0; i<AUDIT_NR_FILTERS; i++) {
1050 list_for_each_entry(r, &audit_rules_list[i], list) {
1051 struct audit_rule_data *data;
1052
1053 data = audit_krule_to_data(r);
1054 if (unlikely(!data))
1055 break;
1056 skb = audit_make_reply(portid, seq, AUDIT_LIST_RULES,
1057 0, 1, data,
1058 sizeof(*data) + data->buflen);
1059 if (skb)
1060 skb_queue_tail(q, skb);
1061 kfree(data);
1062 }
1063 }
1064 skb = audit_make_reply(portid, seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);
1065 if (skb)
1066 skb_queue_tail(q, skb);
1067 }
1068
1069 /* Log rule additions and removals */
audit_log_rule_change(char * action,struct audit_krule * rule,int res)1070 static void audit_log_rule_change(char *action, struct audit_krule *rule, int res)
1071 {
1072 struct audit_buffer *ab;
1073 uid_t loginuid = from_kuid(&init_user_ns, audit_get_loginuid(current));
1074 unsigned int sessionid = audit_get_sessionid(current);
1075
1076 if (!audit_enabled)
1077 return;
1078
1079 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
1080 if (!ab)
1081 return;
1082 audit_log_format(ab, "auid=%u ses=%u" ,loginuid, sessionid);
1083 audit_log_task_context(ab);
1084 audit_log_format(ab, " op=");
1085 audit_log_string(ab, action);
1086 audit_log_key(ab, rule->filterkey);
1087 audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
1088 audit_log_end(ab);
1089 }
1090
1091 /**
1092 * audit_rule_change - apply all rules to the specified message type
1093 * @type: audit message type
1094 * @portid: target port id for netlink audit messages
1095 * @seq: netlink audit message sequence (serial) number
1096 * @data: payload data
1097 * @datasz: size of payload data
1098 */
audit_rule_change(int type,__u32 portid,int seq,void * data,size_t datasz)1099 int audit_rule_change(int type, __u32 portid, int seq, void *data,
1100 size_t datasz)
1101 {
1102 int err = 0;
1103 struct audit_entry *entry;
1104
1105 switch (type) {
1106 case AUDIT_ADD_RULE:
1107 entry = audit_data_to_entry(data, datasz);
1108 if (IS_ERR(entry))
1109 return PTR_ERR(entry);
1110 err = audit_add_rule(entry);
1111 audit_log_rule_change("add_rule", &entry->rule, !err);
1112 break;
1113 case AUDIT_DEL_RULE:
1114 entry = audit_data_to_entry(data, datasz);
1115 if (IS_ERR(entry))
1116 return PTR_ERR(entry);
1117 err = audit_del_rule(entry);
1118 audit_log_rule_change("remove_rule", &entry->rule, !err);
1119 break;
1120 default:
1121 WARN_ON(1);
1122 return -EINVAL;
1123 }
1124
1125 if (err || type == AUDIT_DEL_RULE) {
1126 if (entry->rule.exe)
1127 audit_remove_mark(entry->rule.exe);
1128 audit_free_rule(entry);
1129 }
1130
1131 return err;
1132 }
1133
1134 /**
1135 * audit_list_rules_send - list the audit rules
1136 * @request_skb: skb of request we are replying to (used to target the reply)
1137 * @seq: netlink audit message sequence (serial) number
1138 */
audit_list_rules_send(struct sk_buff * request_skb,int seq)1139 int audit_list_rules_send(struct sk_buff *request_skb, int seq)
1140 {
1141 u32 portid = NETLINK_CB(request_skb).portid;
1142 struct net *net = sock_net(NETLINK_CB(request_skb).sk);
1143 struct task_struct *tsk;
1144 struct audit_netlink_list *dest;
1145 int err = 0;
1146
1147 /* We can't just spew out the rules here because we might fill
1148 * the available socket buffer space and deadlock waiting for
1149 * auditctl to read from it... which isn't ever going to
1150 * happen if we're actually running in the context of auditctl
1151 * trying to _send_ the stuff */
1152
1153 dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL);
1154 if (!dest)
1155 return -ENOMEM;
1156 dest->net = get_net(net);
1157 dest->portid = portid;
1158 skb_queue_head_init(&dest->q);
1159
1160 mutex_lock(&audit_filter_mutex);
1161 audit_list_rules(portid, seq, &dest->q);
1162 mutex_unlock(&audit_filter_mutex);
1163
1164 tsk = kthread_run(audit_send_list, dest, "audit_send_list");
1165 if (IS_ERR(tsk)) {
1166 skb_queue_purge(&dest->q);
1167 kfree(dest);
1168 err = PTR_ERR(tsk);
1169 }
1170
1171 return err;
1172 }
1173
audit_comparator(u32 left,u32 op,u32 right)1174 int audit_comparator(u32 left, u32 op, u32 right)
1175 {
1176 switch (op) {
1177 case Audit_equal:
1178 return (left == right);
1179 case Audit_not_equal:
1180 return (left != right);
1181 case Audit_lt:
1182 return (left < right);
1183 case Audit_le:
1184 return (left <= right);
1185 case Audit_gt:
1186 return (left > right);
1187 case Audit_ge:
1188 return (left >= right);
1189 case Audit_bitmask:
1190 return (left & right);
1191 case Audit_bittest:
1192 return ((left & right) == right);
1193 default:
1194 BUG();
1195 return 0;
1196 }
1197 }
1198
audit_uid_comparator(kuid_t left,u32 op,kuid_t right)1199 int audit_uid_comparator(kuid_t left, u32 op, kuid_t right)
1200 {
1201 switch (op) {
1202 case Audit_equal:
1203 return uid_eq(left, right);
1204 case Audit_not_equal:
1205 return !uid_eq(left, right);
1206 case Audit_lt:
1207 return uid_lt(left, right);
1208 case Audit_le:
1209 return uid_lte(left, right);
1210 case Audit_gt:
1211 return uid_gt(left, right);
1212 case Audit_ge:
1213 return uid_gte(left, right);
1214 case Audit_bitmask:
1215 case Audit_bittest:
1216 default:
1217 BUG();
1218 return 0;
1219 }
1220 }
1221
audit_gid_comparator(kgid_t left,u32 op,kgid_t right)1222 int audit_gid_comparator(kgid_t left, u32 op, kgid_t right)
1223 {
1224 switch (op) {
1225 case Audit_equal:
1226 return gid_eq(left, right);
1227 case Audit_not_equal:
1228 return !gid_eq(left, right);
1229 case Audit_lt:
1230 return gid_lt(left, right);
1231 case Audit_le:
1232 return gid_lte(left, right);
1233 case Audit_gt:
1234 return gid_gt(left, right);
1235 case Audit_ge:
1236 return gid_gte(left, right);
1237 case Audit_bitmask:
1238 case Audit_bittest:
1239 default:
1240 BUG();
1241 return 0;
1242 }
1243 }
1244
1245 /**
1246 * parent_len - find the length of the parent portion of a pathname
1247 * @path: pathname of which to determine length
1248 */
parent_len(const char * path)1249 int parent_len(const char *path)
1250 {
1251 int plen;
1252 const char *p;
1253
1254 plen = strlen(path);
1255
1256 if (plen == 0)
1257 return plen;
1258
1259 /* disregard trailing slashes */
1260 p = path + plen - 1;
1261 while ((*p == '/') && (p > path))
1262 p--;
1263
1264 /* walk backward until we find the next slash or hit beginning */
1265 while ((*p != '/') && (p > path))
1266 p--;
1267
1268 /* did we find a slash? Then increment to include it in path */
1269 if (*p == '/')
1270 p++;
1271
1272 return p - path;
1273 }
1274
1275 /**
1276 * audit_compare_dname_path - compare given dentry name with last component in
1277 * given path. Return of 0 indicates a match.
1278 * @dname: dentry name that we're comparing
1279 * @path: full pathname that we're comparing
1280 * @parentlen: length of the parent if known. Passing in AUDIT_NAME_FULL
1281 * here indicates that we must compute this value.
1282 */
audit_compare_dname_path(const char * dname,const char * path,int parentlen)1283 int audit_compare_dname_path(const char *dname, const char *path, int parentlen)
1284 {
1285 int dlen, pathlen;
1286 const char *p;
1287
1288 dlen = strlen(dname);
1289 pathlen = strlen(path);
1290 if (pathlen < dlen)
1291 return 1;
1292
1293 parentlen = parentlen == AUDIT_NAME_FULL ? parent_len(path) : parentlen;
1294 if (pathlen - parentlen != dlen)
1295 return 1;
1296
1297 p = path + parentlen;
1298
1299 return strncmp(p, dname, dlen);
1300 }
1301
audit_filter_user_rules(struct audit_krule * rule,int type,enum audit_state * state)1302 static int audit_filter_user_rules(struct audit_krule *rule, int type,
1303 enum audit_state *state)
1304 {
1305 int i;
1306
1307 for (i = 0; i < rule->field_count; i++) {
1308 struct audit_field *f = &rule->fields[i];
1309 pid_t pid;
1310 int result = 0;
1311 u32 sid;
1312
1313 switch (f->type) {
1314 case AUDIT_PID:
1315 pid = task_pid_nr(current);
1316 result = audit_comparator(pid, f->op, f->val);
1317 break;
1318 case AUDIT_UID:
1319 result = audit_uid_comparator(current_uid(), f->op, f->uid);
1320 break;
1321 case AUDIT_GID:
1322 result = audit_gid_comparator(current_gid(), f->op, f->gid);
1323 break;
1324 case AUDIT_LOGINUID:
1325 result = audit_uid_comparator(audit_get_loginuid(current),
1326 f->op, f->uid);
1327 break;
1328 case AUDIT_LOGINUID_SET:
1329 result = audit_comparator(audit_loginuid_set(current),
1330 f->op, f->val);
1331 break;
1332 case AUDIT_MSGTYPE:
1333 result = audit_comparator(type, f->op, f->val);
1334 break;
1335 case AUDIT_SUBJ_USER:
1336 case AUDIT_SUBJ_ROLE:
1337 case AUDIT_SUBJ_TYPE:
1338 case AUDIT_SUBJ_SEN:
1339 case AUDIT_SUBJ_CLR:
1340 if (f->lsm_rule) {
1341 security_task_getsecid(current, &sid);
1342 result = security_audit_rule_match(sid,
1343 f->type,
1344 f->op,
1345 f->lsm_rule,
1346 NULL);
1347 }
1348 break;
1349 }
1350
1351 if (!result)
1352 return 0;
1353 }
1354 switch (rule->action) {
1355 case AUDIT_NEVER: *state = AUDIT_DISABLED; break;
1356 case AUDIT_ALWAYS: *state = AUDIT_RECORD_CONTEXT; break;
1357 }
1358 return 1;
1359 }
1360
audit_filter_user(int type)1361 int audit_filter_user(int type)
1362 {
1363 enum audit_state state = AUDIT_DISABLED;
1364 struct audit_entry *e;
1365 int rc, ret;
1366
1367 ret = 1; /* Audit by default */
1368
1369 rcu_read_lock();
1370 list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_USER], list) {
1371 rc = audit_filter_user_rules(&e->rule, type, &state);
1372 if (rc) {
1373 if (rc > 0 && state == AUDIT_DISABLED)
1374 ret = 0;
1375 break;
1376 }
1377 }
1378 rcu_read_unlock();
1379
1380 return ret;
1381 }
1382
audit_filter_type(int type)1383 int audit_filter_type(int type)
1384 {
1385 struct audit_entry *e;
1386 int result = 0;
1387
1388 rcu_read_lock();
1389 if (list_empty(&audit_filter_list[AUDIT_FILTER_TYPE]))
1390 goto unlock_and_return;
1391
1392 list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_TYPE],
1393 list) {
1394 int i;
1395 for (i = 0; i < e->rule.field_count; i++) {
1396 struct audit_field *f = &e->rule.fields[i];
1397 if (f->type == AUDIT_MSGTYPE) {
1398 result = audit_comparator(type, f->op, f->val);
1399 if (!result)
1400 break;
1401 }
1402 }
1403 if (result)
1404 goto unlock_and_return;
1405 }
1406 unlock_and_return:
1407 rcu_read_unlock();
1408 return result;
1409 }
1410
update_lsm_rule(struct audit_krule * r)1411 static int update_lsm_rule(struct audit_krule *r)
1412 {
1413 struct audit_entry *entry = container_of(r, struct audit_entry, rule);
1414 struct audit_entry *nentry;
1415 int err = 0;
1416
1417 if (!security_audit_rule_known(r))
1418 return 0;
1419
1420 nentry = audit_dupe_rule(r);
1421 if (entry->rule.exe)
1422 audit_remove_mark(entry->rule.exe);
1423 if (IS_ERR(nentry)) {
1424 /* save the first error encountered for the
1425 * return value */
1426 err = PTR_ERR(nentry);
1427 audit_panic("error updating LSM filters");
1428 if (r->watch)
1429 list_del(&r->rlist);
1430 list_del_rcu(&entry->list);
1431 list_del(&r->list);
1432 } else {
1433 if (r->watch || r->tree)
1434 list_replace_init(&r->rlist, &nentry->rule.rlist);
1435 list_replace_rcu(&entry->list, &nentry->list);
1436 list_replace(&r->list, &nentry->rule.list);
1437 }
1438 call_rcu(&entry->rcu, audit_free_rule_rcu);
1439
1440 return err;
1441 }
1442
1443 /* This function will re-initialize the lsm_rule field of all applicable rules.
1444 * It will traverse the filter lists serarching for rules that contain LSM
1445 * specific filter fields. When such a rule is found, it is copied, the
1446 * LSM field is re-initialized, and the old rule is replaced with the
1447 * updated rule. */
audit_update_lsm_rules(void)1448 int audit_update_lsm_rules(void)
1449 {
1450 struct audit_krule *r, *n;
1451 int i, err = 0;
1452
1453 /* audit_filter_mutex synchronizes the writers */
1454 mutex_lock(&audit_filter_mutex);
1455
1456 for (i = 0; i < AUDIT_NR_FILTERS; i++) {
1457 list_for_each_entry_safe(r, n, &audit_rules_list[i], list) {
1458 int res = update_lsm_rule(r);
1459 if (!err)
1460 err = res;
1461 }
1462 }
1463 mutex_unlock(&audit_filter_mutex);
1464
1465 return err;
1466 }
1467