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