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