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1/* auditfilter.c -- filtering of audit events
2 *
3 * Copyright 2003-2004 Red Hat, Inc.
4 * Copyright 2005 Hewlett-Packard Development Company, L.P.
5 * Copyright 2005 IBM Corporation
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 */
21
22#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/* auditfilter.c -- filtering of audit events
2 *
3 * Copyright 2003-2004 Red Hat, Inc.
4 * Copyright 2005 Hewlett-Packard Development Company, L.P.
5 * Copyright 2005 IBM Corporation
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 */
21
22#include <linux/kernel.h>
23#include <linux/audit.h>
24#include <linux/kthread.h>
25#include <linux/mutex.h>
26#include <linux/fs.h>
27#include <linux/namei.h>
28#include <linux/netlink.h>
29#include <linux/sched.h>
30#include <linux/slab.h>
31#include <linux/security.h>
32#include "audit.h"
33
34/*
35 * Locking model:
36 *
37 * audit_filter_mutex:
38 * Synchronizes writes and blocking reads of audit's filterlist
39 * data. Rcu is used to traverse the filterlist and access
40 * contents of structs audit_entry, audit_watch and opaque
41 * LSM rules during filtering. If modified, these structures
42 * must be copied and replace their counterparts in the filterlist.
43 * An audit_parent struct is not accessed during filtering, so may
44 * be written directly provided audit_filter_mutex is held.
45 */
46
47/* Audit filter lists, defined in <linux/audit.h> */
48struct list_head audit_filter_list[AUDIT_NR_FILTERS] = {
49 LIST_HEAD_INIT(audit_filter_list[0]),
50 LIST_HEAD_INIT(audit_filter_list[1]),
51 LIST_HEAD_INIT(audit_filter_list[2]),
52 LIST_HEAD_INIT(audit_filter_list[3]),
53 LIST_HEAD_INIT(audit_filter_list[4]),
54 LIST_HEAD_INIT(audit_filter_list[5]),
55#if AUDIT_NR_FILTERS != 6
56#error Fix audit_filter_list initialiser
57#endif
58};
59static struct list_head audit_rules_list[AUDIT_NR_FILTERS] = {
60 LIST_HEAD_INIT(audit_rules_list[0]),
61 LIST_HEAD_INIT(audit_rules_list[1]),
62 LIST_HEAD_INIT(audit_rules_list[2]),
63 LIST_HEAD_INIT(audit_rules_list[3]),
64 LIST_HEAD_INIT(audit_rules_list[4]),
65 LIST_HEAD_INIT(audit_rules_list[5]),
66};
67
68DEFINE_MUTEX(audit_filter_mutex);
69
70static inline void audit_free_rule(struct audit_entry *e)
71{
72 int i;
73 struct audit_krule *erule = &e->rule;
74
75 /* some rules don't have associated watches */
76 if (erule->watch)
77 audit_put_watch(erule->watch);
78 if (erule->fields)
79 for (i = 0; i < erule->field_count; i++) {
80 struct audit_field *f = &erule->fields[i];
81 kfree(f->lsm_str);
82 security_audit_rule_free(f->lsm_rule);
83 }
84 kfree(erule->fields);
85 kfree(erule->filterkey);
86 kfree(e);
87}
88
89void audit_free_rule_rcu(struct rcu_head *head)
90{
91 struct audit_entry *e = container_of(head, struct audit_entry, rcu);
92 audit_free_rule(e);
93}
94
95/* Initialize an audit filterlist entry. */
96static inline struct audit_entry *audit_init_entry(u32 field_count)
97{
98 struct audit_entry *entry;
99 struct audit_field *fields;
100
101 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
102 if (unlikely(!entry))
103 return NULL;
104
105 fields = kzalloc(sizeof(*fields) * field_count, GFP_KERNEL);
106 if (unlikely(!fields)) {
107 kfree(entry);
108 return NULL;
109 }
110 entry->rule.fields = fields;
111
112 return entry;
113}
114
115/* Unpack a filter field's string representation from user-space
116 * buffer. */
117char *audit_unpack_string(void **bufp, size_t *remain, size_t len)
118{
119 char *str;
120
121 if (!*bufp || (len == 0) || (len > *remain))
122 return ERR_PTR(-EINVAL);
123
124 /* Of the currently implemented string fields, PATH_MAX
125 * defines the longest valid length.
126 */
127 if (len > PATH_MAX)
128 return ERR_PTR(-ENAMETOOLONG);
129
130 str = kmalloc(len + 1, GFP_KERNEL);
131 if (unlikely(!str))
132 return ERR_PTR(-ENOMEM);
133
134 memcpy(str, *bufp, len);
135 str[len] = 0;
136 *bufp += len;
137 *remain -= len;
138
139 return str;
140}
141
142/* Translate an inode field to kernel respresentation. */
143static inline int audit_to_inode(struct audit_krule *krule,
144 struct audit_field *f)
145{
146 if (krule->listnr != AUDIT_FILTER_EXIT ||
147 krule->watch || krule->inode_f || krule->tree ||
148 (f->op != Audit_equal && f->op != Audit_not_equal))
149 return -EINVAL;
150
151 krule->inode_f = f;
152 return 0;
153}
154
155static __u32 *classes[AUDIT_SYSCALL_CLASSES];
156
157int __init audit_register_class(int class, unsigned *list)
158{
159 __u32 *p = kzalloc(AUDIT_BITMASK_SIZE * sizeof(__u32), GFP_KERNEL);
160 if (!p)
161 return -ENOMEM;
162 while (*list != ~0U) {
163 unsigned n = *list++;
164 if (n >= AUDIT_BITMASK_SIZE * 32 - AUDIT_SYSCALL_CLASSES) {
165 kfree(p);
166 return -EINVAL;
167 }
168 p[AUDIT_WORD(n)] |= AUDIT_BIT(n);
169 }
170 if (class >= AUDIT_SYSCALL_CLASSES || classes[class]) {
171 kfree(p);
172 return -EINVAL;
173 }
174 classes[class] = p;
175 return 0;
176}
177
178int audit_match_class(int class, unsigned syscall)
179{
180 if (unlikely(syscall >= AUDIT_BITMASK_SIZE * 32))
181 return 0;
182 if (unlikely(class >= AUDIT_SYSCALL_CLASSES || !classes[class]))
183 return 0;
184 return classes[class][AUDIT_WORD(syscall)] & AUDIT_BIT(syscall);
185}
186
187#ifdef CONFIG_AUDITSYSCALL
188static inline int audit_match_class_bits(int class, u32 *mask)
189{
190 int i;
191
192 if (classes[class]) {
193 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
194 if (mask[i] & classes[class][i])
195 return 0;
196 }
197 return 1;
198}
199
200static int audit_match_signal(struct audit_entry *entry)
201{
202 struct audit_field *arch = entry->rule.arch_f;
203
204 if (!arch) {
205 /* When arch is unspecified, we must check both masks on biarch
206 * as syscall number alone is ambiguous. */
207 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
208 entry->rule.mask) &&
209 audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
210 entry->rule.mask));
211 }
212
213 switch(audit_classify_arch(arch->val)) {
214 case 0: /* native */
215 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
216 entry->rule.mask));
217 case 1: /* 32bit on biarch */
218 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
219 entry->rule.mask));
220 default:
221 return 1;
222 }
223}
224#endif
225
226/* Common user-space to kernel rule translation. */
227static inline struct audit_entry *audit_to_entry_common(struct audit_rule *rule)
228{
229 unsigned listnr;
230 struct audit_entry *entry;
231 int i, err;
232
233 err = -EINVAL;
234 listnr = rule->flags & ~AUDIT_FILTER_PREPEND;
235 switch(listnr) {
236 default:
237 goto exit_err;
238 case AUDIT_FILTER_USER:
239 case AUDIT_FILTER_TYPE:
240#ifdef CONFIG_AUDITSYSCALL
241 case AUDIT_FILTER_ENTRY:
242 case AUDIT_FILTER_EXIT:
243 case AUDIT_FILTER_TASK:
244#endif
245 ;
246 }
247 if (unlikely(rule->action == AUDIT_POSSIBLE)) {
248 printk(KERN_ERR "AUDIT_POSSIBLE is deprecated\n");
249 goto exit_err;
250 }
251 if (rule->action != AUDIT_NEVER && rule->action != AUDIT_ALWAYS)
252 goto exit_err;
253 if (rule->field_count > AUDIT_MAX_FIELDS)
254 goto exit_err;
255
256 err = -ENOMEM;
257 entry = audit_init_entry(rule->field_count);
258 if (!entry)
259 goto exit_err;
260
261 entry->rule.flags = rule->flags & AUDIT_FILTER_PREPEND;
262 entry->rule.listnr = listnr;
263 entry->rule.action = rule->action;
264 entry->rule.field_count = rule->field_count;
265
266 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
267 entry->rule.mask[i] = rule->mask[i];
268
269 for (i = 0; i < AUDIT_SYSCALL_CLASSES; i++) {
270 int bit = AUDIT_BITMASK_SIZE * 32 - i - 1;
271 __u32 *p = &entry->rule.mask[AUDIT_WORD(bit)];
272 __u32 *class;
273
274 if (!(*p & AUDIT_BIT(bit)))
275 continue;
276 *p &= ~AUDIT_BIT(bit);
277 class = classes[i];
278 if (class) {
279 int j;
280 for (j = 0; j < AUDIT_BITMASK_SIZE; j++)
281 entry->rule.mask[j] |= class[j];
282 }
283 }
284
285 return entry;
286
287exit_err:
288 return ERR_PTR(err);
289}
290
291static u32 audit_ops[] =
292{
293 [Audit_equal] = AUDIT_EQUAL,
294 [Audit_not_equal] = AUDIT_NOT_EQUAL,
295 [Audit_bitmask] = AUDIT_BIT_MASK,
296 [Audit_bittest] = AUDIT_BIT_TEST,
297 [Audit_lt] = AUDIT_LESS_THAN,
298 [Audit_gt] = AUDIT_GREATER_THAN,
299 [Audit_le] = AUDIT_LESS_THAN_OR_EQUAL,
300 [Audit_ge] = AUDIT_GREATER_THAN_OR_EQUAL,
301};
302
303static u32 audit_to_op(u32 op)
304{
305 u32 n;
306 for (n = Audit_equal; n < Audit_bad && audit_ops[n] != op; n++)
307 ;
308 return n;
309}
310
311
312/* Translate struct audit_rule to kernel's rule respresentation.
313 * Exists for backward compatibility with userspace. */
314static struct audit_entry *audit_rule_to_entry(struct audit_rule *rule)
315{
316 struct audit_entry *entry;
317 int err = 0;
318 int i;
319
320 entry = audit_to_entry_common(rule);
321 if (IS_ERR(entry))
322 goto exit_nofree;
323
324 for (i = 0; i < rule->field_count; i++) {
325 struct audit_field *f = &entry->rule.fields[i];
326 u32 n;
327
328 n = rule->fields[i] & (AUDIT_NEGATE|AUDIT_OPERATORS);
329
330 /* Support for legacy operators where
331 * AUDIT_NEGATE bit signifies != and otherwise assumes == */
332 if (n & AUDIT_NEGATE)
333 f->op = Audit_not_equal;
334 else if (!n)
335 f->op = Audit_equal;
336 else
337 f->op = audit_to_op(n);
338
339 entry->rule.vers_ops = (n & AUDIT_OPERATORS) ? 2 : 1;
340
341 f->type = rule->fields[i] & ~(AUDIT_NEGATE|AUDIT_OPERATORS);
342 f->val = rule->values[i];
343
344 err = -EINVAL;
345 if (f->op == Audit_bad)
346 goto exit_free;
347
348 switch(f->type) {
349 default:
350 goto exit_free;
351 case AUDIT_PID:
352 case AUDIT_UID:
353 case AUDIT_EUID:
354 case AUDIT_SUID:
355 case AUDIT_FSUID:
356 case AUDIT_GID:
357 case AUDIT_EGID:
358 case AUDIT_SGID:
359 case AUDIT_FSGID:
360 case AUDIT_LOGINUID:
361 case AUDIT_PERS:
362 case AUDIT_MSGTYPE:
363 case AUDIT_PPID:
364 case AUDIT_DEVMAJOR:
365 case AUDIT_DEVMINOR:
366 case AUDIT_EXIT:
367 case AUDIT_SUCCESS:
368 /* bit ops are only useful on syscall args */
369 if (f->op == Audit_bitmask || f->op == Audit_bittest)
370 goto exit_free;
371 break;
372 case AUDIT_ARG0:
373 case AUDIT_ARG1:
374 case AUDIT_ARG2:
375 case AUDIT_ARG3:
376 break;
377 /* arch is only allowed to be = or != */
378 case AUDIT_ARCH:
379 if (f->op != Audit_not_equal && f->op != Audit_equal)
380 goto exit_free;
381 entry->rule.arch_f = f;
382 break;
383 case AUDIT_PERM:
384 if (f->val & ~15)
385 goto exit_free;
386 break;
387 case AUDIT_FILETYPE:
388 if ((f->val & ~S_IFMT) > S_IFMT)
389 goto exit_free;
390 break;
391 case AUDIT_INODE:
392 err = audit_to_inode(&entry->rule, f);
393 if (err)
394 goto exit_free;
395 break;
396 }
397 }
398
399 if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal)
400 entry->rule.inode_f = NULL;
401
402exit_nofree:
403 return entry;
404
405exit_free:
406 audit_free_rule(entry);
407 return ERR_PTR(err);
408}
409
410/* Translate struct audit_rule_data to kernel's rule respresentation. */
411static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
412 size_t datasz)
413{
414 int err = 0;
415 struct audit_entry *entry;
416 void *bufp;
417 size_t remain = datasz - sizeof(struct audit_rule_data);
418 int i;
419 char *str;
420
421 entry = audit_to_entry_common((struct audit_rule *)data);
422 if (IS_ERR(entry))
423 goto exit_nofree;
424
425 bufp = data->buf;
426 entry->rule.vers_ops = 2;
427 for (i = 0; i < data->field_count; i++) {
428 struct audit_field *f = &entry->rule.fields[i];
429
430 err = -EINVAL;
431
432 f->op = audit_to_op(data->fieldflags[i]);
433 if (f->op == Audit_bad)
434 goto exit_free;
435
436 f->type = data->fields[i];
437 f->val = data->values[i];
438 f->lsm_str = NULL;
439 f->lsm_rule = NULL;
440 switch(f->type) {
441 case AUDIT_PID:
442 case AUDIT_UID:
443 case AUDIT_EUID:
444 case AUDIT_SUID:
445 case AUDIT_FSUID:
446 case AUDIT_GID:
447 case AUDIT_EGID:
448 case AUDIT_SGID:
449 case AUDIT_FSGID:
450 case AUDIT_LOGINUID:
451 case AUDIT_PERS:
452 case AUDIT_MSGTYPE:
453 case AUDIT_PPID:
454 case AUDIT_DEVMAJOR:
455 case AUDIT_DEVMINOR:
456 case AUDIT_EXIT:
457 case AUDIT_SUCCESS:
458 case AUDIT_ARG0:
459 case AUDIT_ARG1:
460 case AUDIT_ARG2:
461 case AUDIT_ARG3:
462 break;
463 case AUDIT_ARCH:
464 entry->rule.arch_f = f;
465 break;
466 case AUDIT_SUBJ_USER:
467 case AUDIT_SUBJ_ROLE:
468 case AUDIT_SUBJ_TYPE:
469 case AUDIT_SUBJ_SEN:
470 case AUDIT_SUBJ_CLR:
471 case AUDIT_OBJ_USER:
472 case AUDIT_OBJ_ROLE:
473 case AUDIT_OBJ_TYPE:
474 case AUDIT_OBJ_LEV_LOW:
475 case AUDIT_OBJ_LEV_HIGH:
476 str = audit_unpack_string(&bufp, &remain, f->val);
477 if (IS_ERR(str))
478 goto exit_free;
479 entry->rule.buflen += f->val;
480
481 err = security_audit_rule_init(f->type, f->op, str,
482 (void **)&f->lsm_rule);
483 /* Keep currently invalid fields around in case they
484 * become valid after a policy reload. */
485 if (err == -EINVAL) {
486 printk(KERN_WARNING "audit rule for LSM "
487 "\'%s\' is invalid\n", str);
488 err = 0;
489 }
490 if (err) {
491 kfree(str);
492 goto exit_free;
493 } else
494 f->lsm_str = str;
495 break;
496 case AUDIT_WATCH:
497 str = audit_unpack_string(&bufp, &remain, f->val);
498 if (IS_ERR(str))
499 goto exit_free;
500 entry->rule.buflen += f->val;
501
502 err = audit_to_watch(&entry->rule, str, f->val, f->op);
503 if (err) {
504 kfree(str);
505 goto exit_free;
506 }
507 break;
508 case AUDIT_DIR:
509 str = audit_unpack_string(&bufp, &remain, f->val);
510 if (IS_ERR(str))
511 goto exit_free;
512 entry->rule.buflen += f->val;
513
514 err = audit_make_tree(&entry->rule, str, f->op);
515 kfree(str);
516 if (err)
517 goto exit_free;
518 break;
519 case AUDIT_INODE:
520 err = audit_to_inode(&entry->rule, f);
521 if (err)
522 goto exit_free;
523 break;
524 case AUDIT_FILTERKEY:
525 err = -EINVAL;
526 if (entry->rule.filterkey || f->val > AUDIT_MAX_KEY_LEN)
527 goto exit_free;
528 str = audit_unpack_string(&bufp, &remain, f->val);
529 if (IS_ERR(str))
530 goto exit_free;
531 entry->rule.buflen += f->val;
532 entry->rule.filterkey = str;
533 break;
534 case AUDIT_PERM:
535 if (f->val & ~15)
536 goto exit_free;
537 break;
538 case AUDIT_FILETYPE:
539 if ((f->val & ~S_IFMT) > S_IFMT)
540 goto exit_free;
541 break;
542 default:
543 goto exit_free;
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 audit_free_rule(entry);
555 return ERR_PTR(err);
556}
557
558/* Pack a filter field's string representation into data block. */
559static inline size_t audit_pack_string(void **bufp, const char *str)
560{
561 size_t len = strlen(str);
562
563 memcpy(*bufp, str, len);
564 *bufp += len;
565
566 return len;
567}
568
569/* Translate kernel rule respresentation to struct audit_rule.
570 * Exists for backward compatibility with userspace. */
571static struct audit_rule *audit_krule_to_rule(struct audit_krule *krule)
572{
573 struct audit_rule *rule;
574 int i;
575
576 rule = kzalloc(sizeof(*rule), GFP_KERNEL);
577 if (unlikely(!rule))
578 return NULL;
579
580 rule->flags = krule->flags | krule->listnr;
581 rule->action = krule->action;
582 rule->field_count = krule->field_count;
583 for (i = 0; i < rule->field_count; i++) {
584 rule->values[i] = krule->fields[i].val;
585 rule->fields[i] = krule->fields[i].type;
586
587 if (krule->vers_ops == 1) {
588 if (krule->fields[i].op == Audit_not_equal)
589 rule->fields[i] |= AUDIT_NEGATE;
590 } else {
591 rule->fields[i] |= audit_ops[krule->fields[i].op];
592 }
593 }
594 for (i = 0; i < AUDIT_BITMASK_SIZE; i++) rule->mask[i] = krule->mask[i];
595
596 return rule;
597}
598
599/* Translate kernel rule respresentation to struct audit_rule_data. */
600static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule)
601{
602 struct audit_rule_data *data;
603 void *bufp;
604 int i;
605
606 data = kmalloc(sizeof(*data) + krule->buflen, GFP_KERNEL);
607 if (unlikely(!data))
608 return NULL;
609 memset(data, 0, sizeof(*data));
610
611 data->flags = krule->flags | krule->listnr;
612 data->action = krule->action;
613 data->field_count = krule->field_count;
614 bufp = data->buf;
615 for (i = 0; i < data->field_count; i++) {
616 struct audit_field *f = &krule->fields[i];
617
618 data->fields[i] = f->type;
619 data->fieldflags[i] = audit_ops[f->op];
620 switch(f->type) {
621 case AUDIT_SUBJ_USER:
622 case AUDIT_SUBJ_ROLE:
623 case AUDIT_SUBJ_TYPE:
624 case AUDIT_SUBJ_SEN:
625 case AUDIT_SUBJ_CLR:
626 case AUDIT_OBJ_USER:
627 case AUDIT_OBJ_ROLE:
628 case AUDIT_OBJ_TYPE:
629 case AUDIT_OBJ_LEV_LOW:
630 case AUDIT_OBJ_LEV_HIGH:
631 data->buflen += data->values[i] =
632 audit_pack_string(&bufp, f->lsm_str);
633 break;
634 case AUDIT_WATCH:
635 data->buflen += data->values[i] =
636 audit_pack_string(&bufp,
637 audit_watch_path(krule->watch));
638 break;
639 case AUDIT_DIR:
640 data->buflen += data->values[i] =
641 audit_pack_string(&bufp,
642 audit_tree_path(krule->tree));
643 break;
644 case AUDIT_FILTERKEY:
645 data->buflen += data->values[i] =
646 audit_pack_string(&bufp, krule->filterkey);
647 break;
648 default:
649 data->values[i] = f->val;
650 }
651 }
652 for (i = 0; i < AUDIT_BITMASK_SIZE; i++) data->mask[i] = krule->mask[i];
653
654 return data;
655}
656
657/* Compare two rules in kernel format. Considered success if rules
658 * don't match. */
659static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
660{
661 int i;
662
663 if (a->flags != b->flags ||
664 a->listnr != b->listnr ||
665 a->action != b->action ||
666 a->field_count != b->field_count)
667 return 1;
668
669 for (i = 0; i < a->field_count; i++) {
670 if (a->fields[i].type != b->fields[i].type ||
671 a->fields[i].op != b->fields[i].op)
672 return 1;
673
674 switch(a->fields[i].type) {
675 case AUDIT_SUBJ_USER:
676 case AUDIT_SUBJ_ROLE:
677 case AUDIT_SUBJ_TYPE:
678 case AUDIT_SUBJ_SEN:
679 case AUDIT_SUBJ_CLR:
680 case AUDIT_OBJ_USER:
681 case AUDIT_OBJ_ROLE:
682 case AUDIT_OBJ_TYPE:
683 case AUDIT_OBJ_LEV_LOW:
684 case AUDIT_OBJ_LEV_HIGH:
685 if (strcmp(a->fields[i].lsm_str, b->fields[i].lsm_str))
686 return 1;
687 break;
688 case AUDIT_WATCH:
689 if (strcmp(audit_watch_path(a->watch),
690 audit_watch_path(b->watch)))
691 return 1;
692 break;
693 case AUDIT_DIR:
694 if (strcmp(audit_tree_path(a->tree),
695 audit_tree_path(b->tree)))
696 return 1;
697 break;
698 case AUDIT_FILTERKEY:
699 /* both filterkeys exist based on above type compare */
700 if (strcmp(a->filterkey, b->filterkey))
701 return 1;
702 break;
703 default:
704 if (a->fields[i].val != b->fields[i].val)
705 return 1;
706 }
707 }
708
709 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
710 if (a->mask[i] != b->mask[i])
711 return 1;
712
713 return 0;
714}
715
716/* Duplicate LSM field information. The lsm_rule is opaque, so must be
717 * re-initialized. */
718static inline int audit_dupe_lsm_field(struct audit_field *df,
719 struct audit_field *sf)
720{
721 int ret = 0;
722 char *lsm_str;
723
724 /* our own copy of lsm_str */
725 lsm_str = kstrdup(sf->lsm_str, GFP_KERNEL);
726 if (unlikely(!lsm_str))
727 return -ENOMEM;
728 df->lsm_str = lsm_str;
729
730 /* our own (refreshed) copy of lsm_rule */
731 ret = security_audit_rule_init(df->type, df->op, df->lsm_str,
732 (void **)&df->lsm_rule);
733 /* Keep currently invalid fields around in case they
734 * become valid after a policy reload. */
735 if (ret == -EINVAL) {
736 printk(KERN_WARNING "audit rule for LSM \'%s\' is "
737 "invalid\n", df->lsm_str);
738 ret = 0;
739 }
740
741 return ret;
742}
743
744/* Duplicate an audit rule. This will be a deep copy with the exception
745 * of the watch - that pointer is carried over. The LSM specific fields
746 * will be updated in the copy. The point is to be able to replace the old
747 * rule with the new rule in the filterlist, then free the old rule.
748 * The rlist element is undefined; list manipulations are handled apart from
749 * the initial copy. */
750struct audit_entry *audit_dupe_rule(struct audit_krule *old)
751{
752 u32 fcount = old->field_count;
753 struct audit_entry *entry;
754 struct audit_krule *new;
755 char *fk;
756 int i, err = 0;
757
758 entry = audit_init_entry(fcount);
759 if (unlikely(!entry))
760 return ERR_PTR(-ENOMEM);
761
762 new = &entry->rule;
763 new->vers_ops = old->vers_ops;
764 new->flags = old->flags;
765 new->listnr = old->listnr;
766 new->action = old->action;
767 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
768 new->mask[i] = old->mask[i];
769 new->prio = old->prio;
770 new->buflen = old->buflen;
771 new->inode_f = old->inode_f;
772 new->field_count = old->field_count;
773
774 /*
775 * note that we are OK with not refcounting here; audit_match_tree()
776 * never dereferences tree and we can't get false positives there
777 * since we'd have to have rule gone from the list *and* removed
778 * before the chunks found by lookup had been allocated, i.e. before
779 * the beginning of list scan.
780 */
781 new->tree = old->tree;
782 memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount);
783
784 /* deep copy this information, updating the lsm_rule fields, because
785 * the originals will all be freed when the old rule is freed. */
786 for (i = 0; i < fcount; i++) {
787 switch (new->fields[i].type) {
788 case AUDIT_SUBJ_USER:
789 case AUDIT_SUBJ_ROLE:
790 case AUDIT_SUBJ_TYPE:
791 case AUDIT_SUBJ_SEN:
792 case AUDIT_SUBJ_CLR:
793 case AUDIT_OBJ_USER:
794 case AUDIT_OBJ_ROLE:
795 case AUDIT_OBJ_TYPE:
796 case AUDIT_OBJ_LEV_LOW:
797 case AUDIT_OBJ_LEV_HIGH:
798 err = audit_dupe_lsm_field(&new->fields[i],
799 &old->fields[i]);
800 break;
801 case AUDIT_FILTERKEY:
802 fk = kstrdup(old->filterkey, GFP_KERNEL);
803 if (unlikely(!fk))
804 err = -ENOMEM;
805 else
806 new->filterkey = fk;
807 }
808 if (err) {
809 audit_free_rule(entry);
810 return ERR_PTR(err);
811 }
812 }
813
814 if (old->watch) {
815 audit_get_watch(old->watch);
816 new->watch = old->watch;
817 }
818
819 return entry;
820}
821
822/* Find an existing audit rule.
823 * Caller must hold audit_filter_mutex to prevent stale rule data. */
824static struct audit_entry *audit_find_rule(struct audit_entry *entry,
825 struct list_head **p)
826{
827 struct audit_entry *e, *found = NULL;
828 struct list_head *list;
829 int h;
830
831 if (entry->rule.inode_f) {
832 h = audit_hash_ino(entry->rule.inode_f->val);
833 *p = list = &audit_inode_hash[h];
834 } else if (entry->rule.watch) {
835 /* we don't know the inode number, so must walk entire hash */
836 for (h = 0; h < AUDIT_INODE_BUCKETS; h++) {
837 list = &audit_inode_hash[h];
838 list_for_each_entry(e, list, list)
839 if (!audit_compare_rule(&entry->rule, &e->rule)) {
840 found = e;
841 goto out;
842 }
843 }
844 goto out;
845 } else {
846 *p = list = &audit_filter_list[entry->rule.listnr];
847 }
848
849 list_for_each_entry(e, list, list)
850 if (!audit_compare_rule(&entry->rule, &e->rule)) {
851 found = e;
852 goto out;
853 }
854
855out:
856 return found;
857}
858
859static u64 prio_low = ~0ULL/2;
860static u64 prio_high = ~0ULL/2 - 1;
861
862/* Add rule to given filterlist if not a duplicate. */
863static inline int audit_add_rule(struct audit_entry *entry)
864{
865 struct audit_entry *e;
866 struct audit_watch *watch = entry->rule.watch;
867 struct audit_tree *tree = entry->rule.tree;
868 struct list_head *list;
869 int err;
870#ifdef CONFIG_AUDITSYSCALL
871 int dont_count = 0;
872
873 /* If either of these, don't count towards total */
874 if (entry->rule.listnr == AUDIT_FILTER_USER ||
875 entry->rule.listnr == AUDIT_FILTER_TYPE)
876 dont_count = 1;
877#endif
878
879 mutex_lock(&audit_filter_mutex);
880 e = audit_find_rule(entry, &list);
881 if (e) {
882 mutex_unlock(&audit_filter_mutex);
883 err = -EEXIST;
884 /* normally audit_add_tree_rule() will free it on failure */
885 if (tree)
886 audit_put_tree(tree);
887 goto error;
888 }
889
890 if (watch) {
891 /* audit_filter_mutex is dropped and re-taken during this call */
892 err = audit_add_watch(&entry->rule, &list);
893 if (err) {
894 mutex_unlock(&audit_filter_mutex);
895 goto error;
896 }
897 }
898 if (tree) {
899 err = audit_add_tree_rule(&entry->rule);
900 if (err) {
901 mutex_unlock(&audit_filter_mutex);
902 goto error;
903 }
904 }
905
906 entry->rule.prio = ~0ULL;
907 if (entry->rule.listnr == AUDIT_FILTER_EXIT) {
908 if (entry->rule.flags & AUDIT_FILTER_PREPEND)
909 entry->rule.prio = ++prio_high;
910 else
911 entry->rule.prio = --prio_low;
912 }
913
914 if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
915 list_add(&entry->rule.list,
916 &audit_rules_list[entry->rule.listnr]);
917 list_add_rcu(&entry->list, list);
918 entry->rule.flags &= ~AUDIT_FILTER_PREPEND;
919 } else {
920 list_add_tail(&entry->rule.list,
921 &audit_rules_list[entry->rule.listnr]);
922 list_add_tail_rcu(&entry->list, list);
923 }
924#ifdef CONFIG_AUDITSYSCALL
925 if (!dont_count)
926 audit_n_rules++;
927
928 if (!audit_match_signal(entry))
929 audit_signals++;
930#endif
931 mutex_unlock(&audit_filter_mutex);
932
933 return 0;
934
935error:
936 if (watch)
937 audit_put_watch(watch); /* tmp watch, matches initial get */
938 return err;
939}
940
941/* Remove an existing rule from filterlist. */
942static inline int audit_del_rule(struct audit_entry *entry)
943{
944 struct audit_entry *e;
945 struct audit_watch *watch = entry->rule.watch;
946 struct audit_tree *tree = entry->rule.tree;
947 struct list_head *list;
948 int ret = 0;
949#ifdef CONFIG_AUDITSYSCALL
950 int dont_count = 0;
951
952 /* If either of these, don't count towards total */
953 if (entry->rule.listnr == AUDIT_FILTER_USER ||
954 entry->rule.listnr == AUDIT_FILTER_TYPE)
955 dont_count = 1;
956#endif
957
958 mutex_lock(&audit_filter_mutex);
959 e = audit_find_rule(entry, &list);
960 if (!e) {
961 mutex_unlock(&audit_filter_mutex);
962 ret = -ENOENT;
963 goto out;
964 }
965
966 if (e->rule.watch)
967 audit_remove_watch_rule(&e->rule);
968
969 if (e->rule.tree)
970 audit_remove_tree_rule(&e->rule);
971
972 list_del_rcu(&e->list);
973 list_del(&e->rule.list);
974 call_rcu(&e->rcu, audit_free_rule_rcu);
975
976#ifdef CONFIG_AUDITSYSCALL
977 if (!dont_count)
978 audit_n_rules--;
979
980 if (!audit_match_signal(entry))
981 audit_signals--;
982#endif
983 mutex_unlock(&audit_filter_mutex);
984
985out:
986 if (watch)
987 audit_put_watch(watch); /* match initial get */
988 if (tree)
989 audit_put_tree(tree); /* that's the temporary one */
990
991 return ret;
992}
993
994/* List rules using struct audit_rule. Exists for backward
995 * compatibility with userspace. */
996static void audit_list(int pid, int seq, struct sk_buff_head *q)
997{
998 struct sk_buff *skb;
999 struct audit_krule *r;
1000 int i;
1001
1002 /* This is a blocking read, so use audit_filter_mutex instead of rcu
1003 * iterator to sync with list writers. */
1004 for (i=0; i<AUDIT_NR_FILTERS; i++) {
1005 list_for_each_entry(r, &audit_rules_list[i], list) {
1006 struct audit_rule *rule;
1007
1008 rule = audit_krule_to_rule(r);
1009 if (unlikely(!rule))
1010 break;
1011 skb = audit_make_reply(pid, seq, AUDIT_LIST, 0, 1,
1012 rule, sizeof(*rule));
1013 if (skb)
1014 skb_queue_tail(q, skb);
1015 kfree(rule);
1016 }
1017 }
1018 skb = audit_make_reply(pid, seq, AUDIT_LIST, 1, 1, NULL, 0);
1019 if (skb)
1020 skb_queue_tail(q, skb);
1021}
1022
1023/* List rules using struct audit_rule_data. */
1024static void audit_list_rules(int pid, int seq, struct sk_buff_head *q)
1025{
1026 struct sk_buff *skb;
1027 struct audit_krule *r;
1028 int i;
1029
1030 /* This is a blocking read, so use audit_filter_mutex instead of rcu
1031 * iterator to sync with list writers. */
1032 for (i=0; i<AUDIT_NR_FILTERS; i++) {
1033 list_for_each_entry(r, &audit_rules_list[i], list) {
1034 struct audit_rule_data *data;
1035
1036 data = audit_krule_to_data(r);
1037 if (unlikely(!data))
1038 break;
1039 skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 0, 1,
1040 data, sizeof(*data) + data->buflen);
1041 if (skb)
1042 skb_queue_tail(q, skb);
1043 kfree(data);
1044 }
1045 }
1046 skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);
1047 if (skb)
1048 skb_queue_tail(q, skb);
1049}
1050
1051/* Log rule additions and removals */
1052static void audit_log_rule_change(uid_t loginuid, u32 sessionid, u32 sid,
1053 char *action, struct audit_krule *rule,
1054 int res)
1055{
1056 struct audit_buffer *ab;
1057
1058 if (!audit_enabled)
1059 return;
1060
1061 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
1062 if (!ab)
1063 return;
1064 audit_log_format(ab, "auid=%u ses=%u", loginuid, sessionid);
1065 if (sid) {
1066 char *ctx = NULL;
1067 u32 len;
1068 if (security_secid_to_secctx(sid, &ctx, &len))
1069 audit_log_format(ab, " ssid=%u", sid);
1070 else {
1071 audit_log_format(ab, " subj=%s", ctx);
1072 security_release_secctx(ctx, len);
1073 }
1074 }
1075 audit_log_format(ab, " op=");
1076 audit_log_string(ab, action);
1077 audit_log_key(ab, rule->filterkey);
1078 audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
1079 audit_log_end(ab);
1080}
1081
1082/**
1083 * audit_receive_filter - apply all rules to the specified message type
1084 * @type: audit message type
1085 * @pid: target pid for netlink audit messages
1086 * @uid: target uid for netlink audit messages
1087 * @seq: netlink audit message sequence (serial) number
1088 * @data: payload data
1089 * @datasz: size of payload data
1090 * @loginuid: loginuid of sender
1091 * @sessionid: sessionid for netlink audit message
1092 * @sid: SE Linux Security ID of sender
1093 */
1094int audit_receive_filter(int type, int pid, int uid, int seq, void *data,
1095 size_t datasz, uid_t loginuid, u32 sessionid, u32 sid)
1096{
1097 struct task_struct *tsk;
1098 struct audit_netlink_list *dest;
1099 int err = 0;
1100 struct audit_entry *entry;
1101
1102 switch (type) {
1103 case AUDIT_LIST:
1104 case AUDIT_LIST_RULES:
1105 /* We can't just spew out the rules here because we might fill
1106 * the available socket buffer space and deadlock waiting for
1107 * auditctl to read from it... which isn't ever going to
1108 * happen if we're actually running in the context of auditctl
1109 * trying to _send_ the stuff */
1110
1111 dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL);
1112 if (!dest)
1113 return -ENOMEM;
1114 dest->pid = pid;
1115 skb_queue_head_init(&dest->q);
1116
1117 mutex_lock(&audit_filter_mutex);
1118 if (type == AUDIT_LIST)
1119 audit_list(pid, seq, &dest->q);
1120 else
1121 audit_list_rules(pid, seq, &dest->q);
1122 mutex_unlock(&audit_filter_mutex);
1123
1124 tsk = kthread_run(audit_send_list, dest, "audit_send_list");
1125 if (IS_ERR(tsk)) {
1126 skb_queue_purge(&dest->q);
1127 kfree(dest);
1128 err = PTR_ERR(tsk);
1129 }
1130 break;
1131 case AUDIT_ADD:
1132 case AUDIT_ADD_RULE:
1133 if (type == AUDIT_ADD)
1134 entry = audit_rule_to_entry(data);
1135 else
1136 entry = audit_data_to_entry(data, datasz);
1137 if (IS_ERR(entry))
1138 return PTR_ERR(entry);
1139
1140 err = audit_add_rule(entry);
1141 audit_log_rule_change(loginuid, sessionid, sid, "add rule",
1142 &entry->rule, !err);
1143
1144 if (err)
1145 audit_free_rule(entry);
1146 break;
1147 case AUDIT_DEL:
1148 case AUDIT_DEL_RULE:
1149 if (type == AUDIT_DEL)
1150 entry = audit_rule_to_entry(data);
1151 else
1152 entry = audit_data_to_entry(data, datasz);
1153 if (IS_ERR(entry))
1154 return PTR_ERR(entry);
1155
1156 err = audit_del_rule(entry);
1157 audit_log_rule_change(loginuid, sessionid, sid, "remove rule",
1158 &entry->rule, !err);
1159
1160 audit_free_rule(entry);
1161 break;
1162 default:
1163 return -EINVAL;
1164 }
1165
1166 return err;
1167}
1168
1169int audit_comparator(u32 left, u32 op, u32 right)
1170{
1171 switch (op) {
1172 case Audit_equal:
1173 return (left == right);
1174 case Audit_not_equal:
1175 return (left != right);
1176 case Audit_lt:
1177 return (left < right);
1178 case Audit_le:
1179 return (left <= right);
1180 case Audit_gt:
1181 return (left > right);
1182 case Audit_ge:
1183 return (left >= right);
1184 case Audit_bitmask:
1185 return (left & right);
1186 case Audit_bittest:
1187 return ((left & right) == right);
1188 default:
1189 BUG();
1190 return 0;
1191 }
1192}
1193
1194/* Compare given dentry name with last component in given path,
1195 * return of 0 indicates a match. */
1196int audit_compare_dname_path(const char *dname, const char *path,
1197 int *dirlen)
1198{
1199 int dlen, plen;
1200 const char *p;
1201
1202 if (!dname || !path)
1203 return 1;
1204
1205 dlen = strlen(dname);
1206 plen = strlen(path);
1207 if (plen < dlen)
1208 return 1;
1209
1210 /* disregard trailing slashes */
1211 p = path + plen - 1;
1212 while ((*p == '/') && (p > path))
1213 p--;
1214
1215 /* find last path component */
1216 p = p - dlen + 1;
1217 if (p < path)
1218 return 1;
1219 else if (p > path) {
1220 if (*--p != '/')
1221 return 1;
1222 else
1223 p++;
1224 }
1225
1226 /* return length of path's directory component */
1227 if (dirlen)
1228 *dirlen = p - path;
1229 return strncmp(p, dname, dlen);
1230}
1231
1232static int audit_filter_user_rules(struct netlink_skb_parms *cb,
1233 struct audit_krule *rule,
1234 enum audit_state *state)
1235{
1236 int i;
1237
1238 for (i = 0; i < rule->field_count; i++) {
1239 struct audit_field *f = &rule->fields[i];
1240 int result = 0;
1241 u32 sid;
1242
1243 switch (f->type) {
1244 case AUDIT_PID:
1245 result = audit_comparator(cb->creds.pid, f->op, f->val);
1246 break;
1247 case AUDIT_UID:
1248 result = audit_comparator(cb->creds.uid, f->op, f->val);
1249 break;
1250 case AUDIT_GID:
1251 result = audit_comparator(cb->creds.gid, f->op, f->val);
1252 break;
1253 case AUDIT_LOGINUID:
1254 result = audit_comparator(audit_get_loginuid(current),
1255 f->op, f->val);
1256 break;
1257 case AUDIT_SUBJ_USER:
1258 case AUDIT_SUBJ_ROLE:
1259 case AUDIT_SUBJ_TYPE:
1260 case AUDIT_SUBJ_SEN:
1261 case AUDIT_SUBJ_CLR:
1262 if (f->lsm_rule) {
1263 security_task_getsecid(current, &sid);
1264 result = security_audit_rule_match(sid,
1265 f->type,
1266 f->op,
1267 f->lsm_rule,
1268 NULL);
1269 }
1270 break;
1271 }
1272
1273 if (!result)
1274 return 0;
1275 }
1276 switch (rule->action) {
1277 case AUDIT_NEVER: *state = AUDIT_DISABLED; break;
1278 case AUDIT_ALWAYS: *state = AUDIT_RECORD_CONTEXT; break;
1279 }
1280 return 1;
1281}
1282
1283int audit_filter_user(struct netlink_skb_parms *cb)
1284{
1285 enum audit_state state = AUDIT_DISABLED;
1286 struct audit_entry *e;
1287 int ret = 1;
1288
1289 rcu_read_lock();
1290 list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_USER], list) {
1291 if (audit_filter_user_rules(cb, &e->rule, &state)) {
1292 if (state == AUDIT_DISABLED)
1293 ret = 0;
1294 break;
1295 }
1296 }
1297 rcu_read_unlock();
1298
1299 return ret; /* Audit by default */
1300}
1301
1302int audit_filter_type(int type)
1303{
1304 struct audit_entry *e;
1305 int result = 0;
1306
1307 rcu_read_lock();
1308 if (list_empty(&audit_filter_list[AUDIT_FILTER_TYPE]))
1309 goto unlock_and_return;
1310
1311 list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_TYPE],
1312 list) {
1313 int i;
1314 for (i = 0; i < e->rule.field_count; i++) {
1315 struct audit_field *f = &e->rule.fields[i];
1316 if (f->type == AUDIT_MSGTYPE) {
1317 result = audit_comparator(type, f->op, f->val);
1318 if (!result)
1319 break;
1320 }
1321 }
1322 if (result)
1323 goto unlock_and_return;
1324 }
1325unlock_and_return:
1326 rcu_read_unlock();
1327 return result;
1328}
1329
1330static int update_lsm_rule(struct audit_krule *r)
1331{
1332 struct audit_entry *entry = container_of(r, struct audit_entry, rule);
1333 struct audit_entry *nentry;
1334 int err = 0;
1335
1336 if (!security_audit_rule_known(r))
1337 return 0;
1338
1339 nentry = audit_dupe_rule(r);
1340 if (IS_ERR(nentry)) {
1341 /* save the first error encountered for the
1342 * return value */
1343 err = PTR_ERR(nentry);
1344 audit_panic("error updating LSM filters");
1345 if (r->watch)
1346 list_del(&r->rlist);
1347 list_del_rcu(&entry->list);
1348 list_del(&r->list);
1349 } else {
1350 if (r->watch || r->tree)
1351 list_replace_init(&r->rlist, &nentry->rule.rlist);
1352 list_replace_rcu(&entry->list, &nentry->list);
1353 list_replace(&r->list, &nentry->rule.list);
1354 }
1355 call_rcu(&entry->rcu, audit_free_rule_rcu);
1356
1357 return err;
1358}
1359
1360/* This function will re-initialize the lsm_rule field of all applicable rules.
1361 * It will traverse the filter lists serarching for rules that contain LSM
1362 * specific filter fields. When such a rule is found, it is copied, the
1363 * LSM field is re-initialized, and the old rule is replaced with the
1364 * updated rule. */
1365int audit_update_lsm_rules(void)
1366{
1367 struct audit_krule *r, *n;
1368 int i, err = 0;
1369
1370 /* audit_filter_mutex synchronizes the writers */
1371 mutex_lock(&audit_filter_mutex);
1372
1373 for (i = 0; i < AUDIT_NR_FILTERS; i++) {
1374 list_for_each_entry_safe(r, n, &audit_rules_list[i], list) {
1375 int res = update_lsm_rule(r);
1376 if (!err)
1377 err = res;
1378 }
1379 }
1380 mutex_unlock(&audit_filter_mutex);
1381
1382 return err;
1383}