Loading...
1/* auditfilter.c -- filtering of audit events
2 *
3 * Copyright 2003-2004 Red Hat, Inc.
4 * Copyright 2005 Hewlett-Packard Development Company, L.P.
5 * Copyright 2005 IBM Corporation
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 */
21
22#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
23
24#include <linux/kernel.h>
25#include <linux/audit.h>
26#include <linux/kthread.h>
27#include <linux/mutex.h>
28#include <linux/fs.h>
29#include <linux/namei.h>
30#include <linux/netlink.h>
31#include <linux/sched.h>
32#include <linux/slab.h>
33#include <linux/security.h>
34#include <net/net_namespace.h>
35#include <net/sock.h>
36#include "audit.h"
37
38/*
39 * Locking model:
40 *
41 * audit_filter_mutex:
42 * Synchronizes writes and blocking reads of audit's filterlist
43 * data. Rcu is used to traverse the filterlist and access
44 * contents of structs audit_entry, audit_watch and opaque
45 * LSM rules during filtering. If modified, these structures
46 * must be copied and replace their counterparts in the filterlist.
47 * An audit_parent struct is not accessed during filtering, so may
48 * be written directly provided audit_filter_mutex is held.
49 */
50
51/* Audit filter lists, defined in <linux/audit.h> */
52struct list_head audit_filter_list[AUDIT_NR_FILTERS] = {
53 LIST_HEAD_INIT(audit_filter_list[0]),
54 LIST_HEAD_INIT(audit_filter_list[1]),
55 LIST_HEAD_INIT(audit_filter_list[2]),
56 LIST_HEAD_INIT(audit_filter_list[3]),
57 LIST_HEAD_INIT(audit_filter_list[4]),
58 LIST_HEAD_INIT(audit_filter_list[5]),
59#if AUDIT_NR_FILTERS != 6
60#error Fix audit_filter_list initialiser
61#endif
62};
63static struct list_head audit_rules_list[AUDIT_NR_FILTERS] = {
64 LIST_HEAD_INIT(audit_rules_list[0]),
65 LIST_HEAD_INIT(audit_rules_list[1]),
66 LIST_HEAD_INIT(audit_rules_list[2]),
67 LIST_HEAD_INIT(audit_rules_list[3]),
68 LIST_HEAD_INIT(audit_rules_list[4]),
69 LIST_HEAD_INIT(audit_rules_list[5]),
70};
71
72DEFINE_MUTEX(audit_filter_mutex);
73
74static void audit_free_lsm_field(struct audit_field *f)
75{
76 switch (f->type) {
77 case AUDIT_SUBJ_USER:
78 case AUDIT_SUBJ_ROLE:
79 case AUDIT_SUBJ_TYPE:
80 case AUDIT_SUBJ_SEN:
81 case AUDIT_SUBJ_CLR:
82 case AUDIT_OBJ_USER:
83 case AUDIT_OBJ_ROLE:
84 case AUDIT_OBJ_TYPE:
85 case AUDIT_OBJ_LEV_LOW:
86 case AUDIT_OBJ_LEV_HIGH:
87 kfree(f->lsm_str);
88 security_audit_rule_free(f->lsm_rule);
89 }
90}
91
92static inline void audit_free_rule(struct audit_entry *e)
93{
94 int i;
95 struct audit_krule *erule = &e->rule;
96
97 /* some rules don't have associated watches */
98 if (erule->watch)
99 audit_put_watch(erule->watch);
100 if (erule->fields)
101 for (i = 0; i < erule->field_count; i++)
102 audit_free_lsm_field(&erule->fields[i]);
103 kfree(erule->fields);
104 kfree(erule->filterkey);
105 kfree(e);
106}
107
108void audit_free_rule_rcu(struct rcu_head *head)
109{
110 struct audit_entry *e = container_of(head, struct audit_entry, rcu);
111 audit_free_rule(e);
112}
113
114/* Initialize an audit filterlist entry. */
115static inline struct audit_entry *audit_init_entry(u32 field_count)
116{
117 struct audit_entry *entry;
118 struct audit_field *fields;
119
120 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
121 if (unlikely(!entry))
122 return NULL;
123
124 fields = kcalloc(field_count, sizeof(*fields), GFP_KERNEL);
125 if (unlikely(!fields)) {
126 kfree(entry);
127 return NULL;
128 }
129 entry->rule.fields = fields;
130
131 return entry;
132}
133
134/* Unpack a filter field's string representation from user-space
135 * buffer. */
136char *audit_unpack_string(void **bufp, size_t *remain, size_t len)
137{
138 char *str;
139
140 if (!*bufp || (len == 0) || (len > *remain))
141 return ERR_PTR(-EINVAL);
142
143 /* Of the currently implemented string fields, PATH_MAX
144 * defines the longest valid length.
145 */
146 if (len > PATH_MAX)
147 return ERR_PTR(-ENAMETOOLONG);
148
149 str = kmalloc(len + 1, GFP_KERNEL);
150 if (unlikely(!str))
151 return ERR_PTR(-ENOMEM);
152
153 memcpy(str, *bufp, len);
154 str[len] = 0;
155 *bufp += len;
156 *remain -= len;
157
158 return str;
159}
160
161/* Translate an inode field to kernel representation. */
162static inline int audit_to_inode(struct audit_krule *krule,
163 struct audit_field *f)
164{
165 if (krule->listnr != AUDIT_FILTER_EXIT ||
166 krule->inode_f || krule->watch || krule->tree ||
167 (f->op != Audit_equal && f->op != Audit_not_equal))
168 return -EINVAL;
169
170 krule->inode_f = f;
171 return 0;
172}
173
174static __u32 *classes[AUDIT_SYSCALL_CLASSES];
175
176int __init audit_register_class(int class, unsigned *list)
177{
178 __u32 *p = kcalloc(AUDIT_BITMASK_SIZE, sizeof(__u32), GFP_KERNEL);
179 if (!p)
180 return -ENOMEM;
181 while (*list != ~0U) {
182 unsigned n = *list++;
183 if (n >= AUDIT_BITMASK_SIZE * 32 - AUDIT_SYSCALL_CLASSES) {
184 kfree(p);
185 return -EINVAL;
186 }
187 p[AUDIT_WORD(n)] |= AUDIT_BIT(n);
188 }
189 if (class >= AUDIT_SYSCALL_CLASSES || classes[class]) {
190 kfree(p);
191 return -EINVAL;
192 }
193 classes[class] = p;
194 return 0;
195}
196
197int audit_match_class(int class, unsigned syscall)
198{
199 if (unlikely(syscall >= AUDIT_BITMASK_SIZE * 32))
200 return 0;
201 if (unlikely(class >= AUDIT_SYSCALL_CLASSES || !classes[class]))
202 return 0;
203 return classes[class][AUDIT_WORD(syscall)] & AUDIT_BIT(syscall);
204}
205
206#ifdef CONFIG_AUDITSYSCALL
207static inline int audit_match_class_bits(int class, u32 *mask)
208{
209 int i;
210
211 if (classes[class]) {
212 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
213 if (mask[i] & classes[class][i])
214 return 0;
215 }
216 return 1;
217}
218
219static int audit_match_signal(struct audit_entry *entry)
220{
221 struct audit_field *arch = entry->rule.arch_f;
222
223 if (!arch) {
224 /* When arch is unspecified, we must check both masks on biarch
225 * as syscall number alone is ambiguous. */
226 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
227 entry->rule.mask) &&
228 audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
229 entry->rule.mask));
230 }
231
232 switch(audit_classify_arch(arch->val)) {
233 case 0: /* native */
234 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
235 entry->rule.mask));
236 case 1: /* 32bit on biarch */
237 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
238 entry->rule.mask));
239 default:
240 return 1;
241 }
242}
243#endif
244
245/* Common user-space to kernel rule translation. */
246static inline struct audit_entry *audit_to_entry_common(struct audit_rule_data *rule)
247{
248 unsigned listnr;
249 struct audit_entry *entry;
250 int i, err;
251
252 err = -EINVAL;
253 listnr = rule->flags & ~AUDIT_FILTER_PREPEND;
254 switch(listnr) {
255 default:
256 goto exit_err;
257#ifdef CONFIG_AUDITSYSCALL
258 case AUDIT_FILTER_ENTRY:
259 if (rule->action == AUDIT_ALWAYS)
260 goto exit_err;
261 case AUDIT_FILTER_EXIT:
262 case AUDIT_FILTER_TASK:
263#endif
264 case AUDIT_FILTER_USER:
265 case AUDIT_FILTER_TYPE:
266 ;
267 }
268 if (unlikely(rule->action == AUDIT_POSSIBLE)) {
269 pr_err("AUDIT_POSSIBLE is deprecated\n");
270 goto exit_err;
271 }
272 if (rule->action != AUDIT_NEVER && rule->action != AUDIT_ALWAYS)
273 goto exit_err;
274 if (rule->field_count > AUDIT_MAX_FIELDS)
275 goto exit_err;
276
277 err = -ENOMEM;
278 entry = audit_init_entry(rule->field_count);
279 if (!entry)
280 goto exit_err;
281
282 entry->rule.flags = rule->flags & AUDIT_FILTER_PREPEND;
283 entry->rule.listnr = listnr;
284 entry->rule.action = rule->action;
285 entry->rule.field_count = rule->field_count;
286
287 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
288 entry->rule.mask[i] = rule->mask[i];
289
290 for (i = 0; i < AUDIT_SYSCALL_CLASSES; i++) {
291 int bit = AUDIT_BITMASK_SIZE * 32 - i - 1;
292 __u32 *p = &entry->rule.mask[AUDIT_WORD(bit)];
293 __u32 *class;
294
295 if (!(*p & AUDIT_BIT(bit)))
296 continue;
297 *p &= ~AUDIT_BIT(bit);
298 class = classes[i];
299 if (class) {
300 int j;
301 for (j = 0; j < AUDIT_BITMASK_SIZE; j++)
302 entry->rule.mask[j] |= class[j];
303 }
304 }
305
306 return entry;
307
308exit_err:
309 return ERR_PTR(err);
310}
311
312static u32 audit_ops[] =
313{
314 [Audit_equal] = AUDIT_EQUAL,
315 [Audit_not_equal] = AUDIT_NOT_EQUAL,
316 [Audit_bitmask] = AUDIT_BIT_MASK,
317 [Audit_bittest] = AUDIT_BIT_TEST,
318 [Audit_lt] = AUDIT_LESS_THAN,
319 [Audit_gt] = AUDIT_GREATER_THAN,
320 [Audit_le] = AUDIT_LESS_THAN_OR_EQUAL,
321 [Audit_ge] = AUDIT_GREATER_THAN_OR_EQUAL,
322};
323
324static u32 audit_to_op(u32 op)
325{
326 u32 n;
327 for (n = Audit_equal; n < Audit_bad && audit_ops[n] != op; n++)
328 ;
329 return n;
330}
331
332/* check if an audit field is valid */
333static int audit_field_valid(struct audit_entry *entry, struct audit_field *f)
334{
335 switch(f->type) {
336 case AUDIT_MSGTYPE:
337 if (entry->rule.listnr != AUDIT_FILTER_TYPE &&
338 entry->rule.listnr != AUDIT_FILTER_USER)
339 return -EINVAL;
340 break;
341 };
342
343 switch(f->type) {
344 default:
345 return -EINVAL;
346 case AUDIT_UID:
347 case AUDIT_EUID:
348 case AUDIT_SUID:
349 case AUDIT_FSUID:
350 case AUDIT_LOGINUID:
351 case AUDIT_OBJ_UID:
352 case AUDIT_GID:
353 case AUDIT_EGID:
354 case AUDIT_SGID:
355 case AUDIT_FSGID:
356 case AUDIT_OBJ_GID:
357 case AUDIT_PID:
358 case AUDIT_PERS:
359 case AUDIT_MSGTYPE:
360 case AUDIT_PPID:
361 case AUDIT_DEVMAJOR:
362 case AUDIT_DEVMINOR:
363 case AUDIT_EXIT:
364 case AUDIT_SUCCESS:
365 case AUDIT_INODE:
366 case AUDIT_SESSIONID:
367 /* bit ops are only useful on syscall args */
368 if (f->op == Audit_bitmask || f->op == Audit_bittest)
369 return -EINVAL;
370 break;
371 case AUDIT_ARG0:
372 case AUDIT_ARG1:
373 case AUDIT_ARG2:
374 case AUDIT_ARG3:
375 case AUDIT_SUBJ_USER:
376 case AUDIT_SUBJ_ROLE:
377 case AUDIT_SUBJ_TYPE:
378 case AUDIT_SUBJ_SEN:
379 case AUDIT_SUBJ_CLR:
380 case AUDIT_OBJ_USER:
381 case AUDIT_OBJ_ROLE:
382 case AUDIT_OBJ_TYPE:
383 case AUDIT_OBJ_LEV_LOW:
384 case AUDIT_OBJ_LEV_HIGH:
385 case AUDIT_WATCH:
386 case AUDIT_DIR:
387 case AUDIT_FILTERKEY:
388 break;
389 case AUDIT_LOGINUID_SET:
390 if ((f->val != 0) && (f->val != 1))
391 return -EINVAL;
392 /* FALL THROUGH */
393 case AUDIT_ARCH:
394 if (f->op != Audit_not_equal && f->op != Audit_equal)
395 return -EINVAL;
396 break;
397 case AUDIT_PERM:
398 if (f->val & ~15)
399 return -EINVAL;
400 break;
401 case AUDIT_FILETYPE:
402 if (f->val & ~S_IFMT)
403 return -EINVAL;
404 break;
405 case AUDIT_FIELD_COMPARE:
406 if (f->val > AUDIT_MAX_FIELD_COMPARE)
407 return -EINVAL;
408 break;
409 case AUDIT_EXE:
410 if (f->op != Audit_equal)
411 return -EINVAL;
412 if (entry->rule.listnr != AUDIT_FILTER_EXIT)
413 return -EINVAL;
414 break;
415 };
416 return 0;
417}
418
419/* Translate struct audit_rule_data to kernel's rule representation. */
420static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
421 size_t datasz)
422{
423 int err = 0;
424 struct audit_entry *entry;
425 void *bufp;
426 size_t remain = datasz - sizeof(struct audit_rule_data);
427 int i;
428 char *str;
429 struct audit_fsnotify_mark *audit_mark;
430
431 entry = audit_to_entry_common(data);
432 if (IS_ERR(entry))
433 goto exit_nofree;
434
435 bufp = data->buf;
436 for (i = 0; i < data->field_count; i++) {
437 struct audit_field *f = &entry->rule.fields[i];
438
439 err = -EINVAL;
440
441 f->op = audit_to_op(data->fieldflags[i]);
442 if (f->op == Audit_bad)
443 goto exit_free;
444
445 f->type = data->fields[i];
446 f->val = data->values[i];
447
448 /* Support legacy tests for a valid loginuid */
449 if ((f->type == AUDIT_LOGINUID) && (f->val == AUDIT_UID_UNSET)) {
450 f->type = AUDIT_LOGINUID_SET;
451 f->val = 0;
452 entry->rule.pflags |= AUDIT_LOGINUID_LEGACY;
453 }
454
455 err = audit_field_valid(entry, f);
456 if (err)
457 goto exit_free;
458
459 err = -EINVAL;
460 switch (f->type) {
461 case AUDIT_LOGINUID:
462 case AUDIT_UID:
463 case AUDIT_EUID:
464 case AUDIT_SUID:
465 case AUDIT_FSUID:
466 case AUDIT_OBJ_UID:
467 f->uid = make_kuid(current_user_ns(), f->val);
468 if (!uid_valid(f->uid))
469 goto exit_free;
470 break;
471 case AUDIT_GID:
472 case AUDIT_EGID:
473 case AUDIT_SGID:
474 case AUDIT_FSGID:
475 case AUDIT_OBJ_GID:
476 f->gid = make_kgid(current_user_ns(), f->val);
477 if (!gid_valid(f->gid))
478 goto exit_free;
479 break;
480 case AUDIT_SESSIONID:
481 case AUDIT_ARCH:
482 entry->rule.arch_f = f;
483 break;
484 case AUDIT_SUBJ_USER:
485 case AUDIT_SUBJ_ROLE:
486 case AUDIT_SUBJ_TYPE:
487 case AUDIT_SUBJ_SEN:
488 case AUDIT_SUBJ_CLR:
489 case AUDIT_OBJ_USER:
490 case AUDIT_OBJ_ROLE:
491 case AUDIT_OBJ_TYPE:
492 case AUDIT_OBJ_LEV_LOW:
493 case AUDIT_OBJ_LEV_HIGH:
494 str = audit_unpack_string(&bufp, &remain, f->val);
495 if (IS_ERR(str))
496 goto exit_free;
497 entry->rule.buflen += f->val;
498
499 err = security_audit_rule_init(f->type, f->op, str,
500 (void **)&f->lsm_rule);
501 /* Keep currently invalid fields around in case they
502 * become valid after a policy reload. */
503 if (err == -EINVAL) {
504 pr_warn("audit rule for LSM \'%s\' is invalid\n",
505 str);
506 err = 0;
507 }
508 if (err) {
509 kfree(str);
510 goto exit_free;
511 } else
512 f->lsm_str = str;
513 break;
514 case AUDIT_WATCH:
515 str = audit_unpack_string(&bufp, &remain, f->val);
516 if (IS_ERR(str))
517 goto exit_free;
518 entry->rule.buflen += f->val;
519
520 err = audit_to_watch(&entry->rule, str, f->val, f->op);
521 if (err) {
522 kfree(str);
523 goto exit_free;
524 }
525 break;
526 case AUDIT_DIR:
527 str = audit_unpack_string(&bufp, &remain, f->val);
528 if (IS_ERR(str))
529 goto exit_free;
530 entry->rule.buflen += f->val;
531
532 err = audit_make_tree(&entry->rule, str, f->op);
533 kfree(str);
534 if (err)
535 goto exit_free;
536 break;
537 case AUDIT_INODE:
538 err = audit_to_inode(&entry->rule, f);
539 if (err)
540 goto exit_free;
541 break;
542 case AUDIT_FILTERKEY:
543 if (entry->rule.filterkey || f->val > AUDIT_MAX_KEY_LEN)
544 goto exit_free;
545 str = audit_unpack_string(&bufp, &remain, f->val);
546 if (IS_ERR(str))
547 goto exit_free;
548 entry->rule.buflen += f->val;
549 entry->rule.filterkey = str;
550 break;
551 case AUDIT_EXE:
552 if (entry->rule.exe || f->val > PATH_MAX)
553 goto exit_free;
554 str = audit_unpack_string(&bufp, &remain, f->val);
555 if (IS_ERR(str)) {
556 err = PTR_ERR(str);
557 goto exit_free;
558 }
559 entry->rule.buflen += f->val;
560
561 audit_mark = audit_alloc_mark(&entry->rule, str, f->val);
562 if (IS_ERR(audit_mark)) {
563 kfree(str);
564 err = PTR_ERR(audit_mark);
565 goto exit_free;
566 }
567 entry->rule.exe = audit_mark;
568 break;
569 }
570 }
571
572 if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal)
573 entry->rule.inode_f = NULL;
574
575exit_nofree:
576 return entry;
577
578exit_free:
579 if (entry->rule.tree)
580 audit_put_tree(entry->rule.tree); /* that's the temporary one */
581 if (entry->rule.exe)
582 audit_remove_mark(entry->rule.exe); /* that's the template one */
583 audit_free_rule(entry);
584 return ERR_PTR(err);
585}
586
587/* Pack a filter field's string representation into data block. */
588static inline size_t audit_pack_string(void **bufp, const char *str)
589{
590 size_t len = strlen(str);
591
592 memcpy(*bufp, str, len);
593 *bufp += len;
594
595 return len;
596}
597
598/* Translate kernel rule representation to struct audit_rule_data. */
599static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule)
600{
601 struct audit_rule_data *data;
602 void *bufp;
603 int i;
604
605 data = kmalloc(sizeof(*data) + krule->buflen, GFP_KERNEL);
606 if (unlikely(!data))
607 return NULL;
608 memset(data, 0, sizeof(*data));
609
610 data->flags = krule->flags | krule->listnr;
611 data->action = krule->action;
612 data->field_count = krule->field_count;
613 bufp = data->buf;
614 for (i = 0; i < data->field_count; i++) {
615 struct audit_field *f = &krule->fields[i];
616
617 data->fields[i] = f->type;
618 data->fieldflags[i] = audit_ops[f->op];
619 switch(f->type) {
620 case AUDIT_SUBJ_USER:
621 case AUDIT_SUBJ_ROLE:
622 case AUDIT_SUBJ_TYPE:
623 case AUDIT_SUBJ_SEN:
624 case AUDIT_SUBJ_CLR:
625 case AUDIT_OBJ_USER:
626 case AUDIT_OBJ_ROLE:
627 case AUDIT_OBJ_TYPE:
628 case AUDIT_OBJ_LEV_LOW:
629 case AUDIT_OBJ_LEV_HIGH:
630 data->buflen += data->values[i] =
631 audit_pack_string(&bufp, f->lsm_str);
632 break;
633 case AUDIT_WATCH:
634 data->buflen += data->values[i] =
635 audit_pack_string(&bufp,
636 audit_watch_path(krule->watch));
637 break;
638 case AUDIT_DIR:
639 data->buflen += data->values[i] =
640 audit_pack_string(&bufp,
641 audit_tree_path(krule->tree));
642 break;
643 case AUDIT_FILTERKEY:
644 data->buflen += data->values[i] =
645 audit_pack_string(&bufp, krule->filterkey);
646 break;
647 case AUDIT_EXE:
648 data->buflen += data->values[i] =
649 audit_pack_string(&bufp, audit_mark_path(krule->exe));
650 break;
651 case AUDIT_LOGINUID_SET:
652 if (krule->pflags & AUDIT_LOGINUID_LEGACY && !f->val) {
653 data->fields[i] = AUDIT_LOGINUID;
654 data->values[i] = AUDIT_UID_UNSET;
655 break;
656 }
657 /* fallthrough if set */
658 default:
659 data->values[i] = f->val;
660 }
661 }
662 for (i = 0; i < AUDIT_BITMASK_SIZE; i++) data->mask[i] = krule->mask[i];
663
664 return data;
665}
666
667/* Compare two rules in kernel format. Considered success if rules
668 * don't match. */
669static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
670{
671 int i;
672
673 if (a->flags != b->flags ||
674 a->pflags != b->pflags ||
675 a->listnr != b->listnr ||
676 a->action != b->action ||
677 a->field_count != b->field_count)
678 return 1;
679
680 for (i = 0; i < a->field_count; i++) {
681 if (a->fields[i].type != b->fields[i].type ||
682 a->fields[i].op != b->fields[i].op)
683 return 1;
684
685 switch(a->fields[i].type) {
686 case AUDIT_SUBJ_USER:
687 case AUDIT_SUBJ_ROLE:
688 case AUDIT_SUBJ_TYPE:
689 case AUDIT_SUBJ_SEN:
690 case AUDIT_SUBJ_CLR:
691 case AUDIT_OBJ_USER:
692 case AUDIT_OBJ_ROLE:
693 case AUDIT_OBJ_TYPE:
694 case AUDIT_OBJ_LEV_LOW:
695 case AUDIT_OBJ_LEV_HIGH:
696 if (strcmp(a->fields[i].lsm_str, b->fields[i].lsm_str))
697 return 1;
698 break;
699 case AUDIT_WATCH:
700 if (strcmp(audit_watch_path(a->watch),
701 audit_watch_path(b->watch)))
702 return 1;
703 break;
704 case AUDIT_DIR:
705 if (strcmp(audit_tree_path(a->tree),
706 audit_tree_path(b->tree)))
707 return 1;
708 break;
709 case AUDIT_FILTERKEY:
710 /* both filterkeys exist based on above type compare */
711 if (strcmp(a->filterkey, b->filterkey))
712 return 1;
713 break;
714 case AUDIT_EXE:
715 /* both paths exist based on above type compare */
716 if (strcmp(audit_mark_path(a->exe),
717 audit_mark_path(b->exe)))
718 return 1;
719 break;
720 case AUDIT_UID:
721 case AUDIT_EUID:
722 case AUDIT_SUID:
723 case AUDIT_FSUID:
724 case AUDIT_LOGINUID:
725 case AUDIT_OBJ_UID:
726 if (!uid_eq(a->fields[i].uid, b->fields[i].uid))
727 return 1;
728 break;
729 case AUDIT_GID:
730 case AUDIT_EGID:
731 case AUDIT_SGID:
732 case AUDIT_FSGID:
733 case AUDIT_OBJ_GID:
734 if (!gid_eq(a->fields[i].gid, b->fields[i].gid))
735 return 1;
736 break;
737 default:
738 if (a->fields[i].val != b->fields[i].val)
739 return 1;
740 }
741 }
742
743 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
744 if (a->mask[i] != b->mask[i])
745 return 1;
746
747 return 0;
748}
749
750/* Duplicate LSM field information. The lsm_rule is opaque, so must be
751 * re-initialized. */
752static inline int audit_dupe_lsm_field(struct audit_field *df,
753 struct audit_field *sf)
754{
755 int ret = 0;
756 char *lsm_str;
757
758 /* our own copy of lsm_str */
759 lsm_str = kstrdup(sf->lsm_str, GFP_KERNEL);
760 if (unlikely(!lsm_str))
761 return -ENOMEM;
762 df->lsm_str = lsm_str;
763
764 /* our own (refreshed) copy of lsm_rule */
765 ret = security_audit_rule_init(df->type, df->op, df->lsm_str,
766 (void **)&df->lsm_rule);
767 /* Keep currently invalid fields around in case they
768 * become valid after a policy reload. */
769 if (ret == -EINVAL) {
770 pr_warn("audit rule for LSM \'%s\' is invalid\n",
771 df->lsm_str);
772 ret = 0;
773 }
774
775 return ret;
776}
777
778/* Duplicate an audit rule. This will be a deep copy with the exception
779 * of the watch - that pointer is carried over. The LSM specific fields
780 * will be updated in the copy. The point is to be able to replace the old
781 * rule with the new rule in the filterlist, then free the old rule.
782 * The rlist element is undefined; list manipulations are handled apart from
783 * the initial copy. */
784struct audit_entry *audit_dupe_rule(struct audit_krule *old)
785{
786 u32 fcount = old->field_count;
787 struct audit_entry *entry;
788 struct audit_krule *new;
789 char *fk;
790 int i, err = 0;
791
792 entry = audit_init_entry(fcount);
793 if (unlikely(!entry))
794 return ERR_PTR(-ENOMEM);
795
796 new = &entry->rule;
797 new->flags = old->flags;
798 new->pflags = old->pflags;
799 new->listnr = old->listnr;
800 new->action = old->action;
801 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
802 new->mask[i] = old->mask[i];
803 new->prio = old->prio;
804 new->buflen = old->buflen;
805 new->inode_f = old->inode_f;
806 new->field_count = old->field_count;
807
808 /*
809 * note that we are OK with not refcounting here; audit_match_tree()
810 * never dereferences tree and we can't get false positives there
811 * since we'd have to have rule gone from the list *and* removed
812 * before the chunks found by lookup had been allocated, i.e. before
813 * the beginning of list scan.
814 */
815 new->tree = old->tree;
816 memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount);
817
818 /* deep copy this information, updating the lsm_rule fields, because
819 * the originals will all be freed when the old rule is freed. */
820 for (i = 0; i < fcount; i++) {
821 switch (new->fields[i].type) {
822 case AUDIT_SUBJ_USER:
823 case AUDIT_SUBJ_ROLE:
824 case AUDIT_SUBJ_TYPE:
825 case AUDIT_SUBJ_SEN:
826 case AUDIT_SUBJ_CLR:
827 case AUDIT_OBJ_USER:
828 case AUDIT_OBJ_ROLE:
829 case AUDIT_OBJ_TYPE:
830 case AUDIT_OBJ_LEV_LOW:
831 case AUDIT_OBJ_LEV_HIGH:
832 err = audit_dupe_lsm_field(&new->fields[i],
833 &old->fields[i]);
834 break;
835 case AUDIT_FILTERKEY:
836 fk = kstrdup(old->filterkey, GFP_KERNEL);
837 if (unlikely(!fk))
838 err = -ENOMEM;
839 else
840 new->filterkey = fk;
841 break;
842 case AUDIT_EXE:
843 err = audit_dupe_exe(new, old);
844 break;
845 }
846 if (err) {
847 if (new->exe)
848 audit_remove_mark(new->exe);
849 audit_free_rule(entry);
850 return ERR_PTR(err);
851 }
852 }
853
854 if (old->watch) {
855 audit_get_watch(old->watch);
856 new->watch = old->watch;
857 }
858
859 return entry;
860}
861
862/* Find an existing audit rule.
863 * Caller must hold audit_filter_mutex to prevent stale rule data. */
864static struct audit_entry *audit_find_rule(struct audit_entry *entry,
865 struct list_head **p)
866{
867 struct audit_entry *e, *found = NULL;
868 struct list_head *list;
869 int h;
870
871 if (entry->rule.inode_f) {
872 h = audit_hash_ino(entry->rule.inode_f->val);
873 *p = list = &audit_inode_hash[h];
874 } else if (entry->rule.watch) {
875 /* we don't know the inode number, so must walk entire hash */
876 for (h = 0; h < AUDIT_INODE_BUCKETS; h++) {
877 list = &audit_inode_hash[h];
878 list_for_each_entry(e, list, list)
879 if (!audit_compare_rule(&entry->rule, &e->rule)) {
880 found = e;
881 goto out;
882 }
883 }
884 goto out;
885 } else {
886 *p = list = &audit_filter_list[entry->rule.listnr];
887 }
888
889 list_for_each_entry(e, list, list)
890 if (!audit_compare_rule(&entry->rule, &e->rule)) {
891 found = e;
892 goto out;
893 }
894
895out:
896 return found;
897}
898
899static u64 prio_low = ~0ULL/2;
900static u64 prio_high = ~0ULL/2 - 1;
901
902/* Add rule to given filterlist if not a duplicate. */
903static inline int audit_add_rule(struct audit_entry *entry)
904{
905 struct audit_entry *e;
906 struct audit_watch *watch = entry->rule.watch;
907 struct audit_tree *tree = entry->rule.tree;
908 struct list_head *list;
909 int err = 0;
910#ifdef CONFIG_AUDITSYSCALL
911 int dont_count = 0;
912
913 /* If either of these, don't count towards total */
914 if (entry->rule.listnr == AUDIT_FILTER_USER ||
915 entry->rule.listnr == AUDIT_FILTER_TYPE)
916 dont_count = 1;
917#endif
918
919 mutex_lock(&audit_filter_mutex);
920 e = audit_find_rule(entry, &list);
921 if (e) {
922 mutex_unlock(&audit_filter_mutex);
923 err = -EEXIST;
924 /* normally audit_add_tree_rule() will free it on failure */
925 if (tree)
926 audit_put_tree(tree);
927 return err;
928 }
929
930 if (watch) {
931 /* audit_filter_mutex is dropped and re-taken during this call */
932 err = audit_add_watch(&entry->rule, &list);
933 if (err) {
934 mutex_unlock(&audit_filter_mutex);
935 /*
936 * normally audit_add_tree_rule() will free it
937 * on failure
938 */
939 if (tree)
940 audit_put_tree(tree);
941 return err;
942 }
943 }
944 if (tree) {
945 err = audit_add_tree_rule(&entry->rule);
946 if (err) {
947 mutex_unlock(&audit_filter_mutex);
948 return err;
949 }
950 }
951
952 entry->rule.prio = ~0ULL;
953 if (entry->rule.listnr == AUDIT_FILTER_EXIT) {
954 if (entry->rule.flags & AUDIT_FILTER_PREPEND)
955 entry->rule.prio = ++prio_high;
956 else
957 entry->rule.prio = --prio_low;
958 }
959
960 if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
961 list_add(&entry->rule.list,
962 &audit_rules_list[entry->rule.listnr]);
963 list_add_rcu(&entry->list, list);
964 entry->rule.flags &= ~AUDIT_FILTER_PREPEND;
965 } else {
966 list_add_tail(&entry->rule.list,
967 &audit_rules_list[entry->rule.listnr]);
968 list_add_tail_rcu(&entry->list, list);
969 }
970#ifdef CONFIG_AUDITSYSCALL
971 if (!dont_count)
972 audit_n_rules++;
973
974 if (!audit_match_signal(entry))
975 audit_signals++;
976#endif
977 mutex_unlock(&audit_filter_mutex);
978
979 return err;
980}
981
982/* Remove an existing rule from filterlist. */
983int audit_del_rule(struct audit_entry *entry)
984{
985 struct audit_entry *e;
986 struct audit_tree *tree = entry->rule.tree;
987 struct list_head *list;
988 int ret = 0;
989#ifdef CONFIG_AUDITSYSCALL
990 int dont_count = 0;
991
992 /* If either of these, don't count towards total */
993 if (entry->rule.listnr == AUDIT_FILTER_USER ||
994 entry->rule.listnr == AUDIT_FILTER_TYPE)
995 dont_count = 1;
996#endif
997
998 mutex_lock(&audit_filter_mutex);
999 e = audit_find_rule(entry, &list);
1000 if (!e) {
1001 ret = -ENOENT;
1002 goto out;
1003 }
1004
1005 if (e->rule.watch)
1006 audit_remove_watch_rule(&e->rule);
1007
1008 if (e->rule.tree)
1009 audit_remove_tree_rule(&e->rule);
1010
1011 if (e->rule.exe)
1012 audit_remove_mark_rule(&e->rule);
1013
1014#ifdef CONFIG_AUDITSYSCALL
1015 if (!dont_count)
1016 audit_n_rules--;
1017
1018 if (!audit_match_signal(entry))
1019 audit_signals--;
1020#endif
1021
1022 list_del_rcu(&e->list);
1023 list_del(&e->rule.list);
1024 call_rcu(&e->rcu, audit_free_rule_rcu);
1025
1026out:
1027 mutex_unlock(&audit_filter_mutex);
1028
1029 if (tree)
1030 audit_put_tree(tree); /* that's the temporary one */
1031
1032 return ret;
1033}
1034
1035/* List rules using struct audit_rule_data. */
1036static void audit_list_rules(__u32 portid, int seq, struct sk_buff_head *q)
1037{
1038 struct sk_buff *skb;
1039 struct audit_krule *r;
1040 int i;
1041
1042 /* This is a blocking read, so use audit_filter_mutex instead of rcu
1043 * iterator to sync with list writers. */
1044 for (i=0; i<AUDIT_NR_FILTERS; i++) {
1045 list_for_each_entry(r, &audit_rules_list[i], list) {
1046 struct audit_rule_data *data;
1047
1048 data = audit_krule_to_data(r);
1049 if (unlikely(!data))
1050 break;
1051 skb = audit_make_reply(portid, seq, AUDIT_LIST_RULES,
1052 0, 1, data,
1053 sizeof(*data) + data->buflen);
1054 if (skb)
1055 skb_queue_tail(q, skb);
1056 kfree(data);
1057 }
1058 }
1059 skb = audit_make_reply(portid, seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);
1060 if (skb)
1061 skb_queue_tail(q, skb);
1062}
1063
1064/* Log rule additions and removals */
1065static void audit_log_rule_change(char *action, struct audit_krule *rule, int res)
1066{
1067 struct audit_buffer *ab;
1068 uid_t loginuid = from_kuid(&init_user_ns, audit_get_loginuid(current));
1069 unsigned int sessionid = audit_get_sessionid(current);
1070
1071 if (!audit_enabled)
1072 return;
1073
1074 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
1075 if (!ab)
1076 return;
1077 audit_log_format(ab, "auid=%u ses=%u" ,loginuid, sessionid);
1078 audit_log_task_context(ab);
1079 audit_log_format(ab, " op=%s", action);
1080 audit_log_key(ab, rule->filterkey);
1081 audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
1082 audit_log_end(ab);
1083}
1084
1085/**
1086 * audit_rule_change - apply all rules to the specified message type
1087 * @type: audit message type
1088 * @portid: target port id for netlink audit messages
1089 * @seq: netlink audit message sequence (serial) number
1090 * @data: payload data
1091 * @datasz: size of payload data
1092 */
1093int audit_rule_change(int type, __u32 portid, int seq, void *data,
1094 size_t datasz)
1095{
1096 int err = 0;
1097 struct audit_entry *entry;
1098
1099 entry = audit_data_to_entry(data, datasz);
1100 if (IS_ERR(entry))
1101 return PTR_ERR(entry);
1102
1103 switch (type) {
1104 case AUDIT_ADD_RULE:
1105 err = audit_add_rule(entry);
1106 audit_log_rule_change("add_rule", &entry->rule, !err);
1107 break;
1108 case AUDIT_DEL_RULE:
1109 err = audit_del_rule(entry);
1110 audit_log_rule_change("remove_rule", &entry->rule, !err);
1111 break;
1112 default:
1113 err = -EINVAL;
1114 WARN_ON(1);
1115 }
1116
1117 if (err || type == AUDIT_DEL_RULE) {
1118 if (entry->rule.exe)
1119 audit_remove_mark(entry->rule.exe);
1120 audit_free_rule(entry);
1121 }
1122
1123 return err;
1124}
1125
1126/**
1127 * audit_list_rules_send - list the audit rules
1128 * @request_skb: skb of request we are replying to (used to target the reply)
1129 * @seq: netlink audit message sequence (serial) number
1130 */
1131int audit_list_rules_send(struct sk_buff *request_skb, int seq)
1132{
1133 u32 portid = NETLINK_CB(request_skb).portid;
1134 struct net *net = sock_net(NETLINK_CB(request_skb).sk);
1135 struct task_struct *tsk;
1136 struct audit_netlink_list *dest;
1137 int err = 0;
1138
1139 /* We can't just spew out the rules here because we might fill
1140 * the available socket buffer space and deadlock waiting for
1141 * auditctl to read from it... which isn't ever going to
1142 * happen if we're actually running in the context of auditctl
1143 * trying to _send_ the stuff */
1144
1145 dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL);
1146 if (!dest)
1147 return -ENOMEM;
1148 dest->net = get_net(net);
1149 dest->portid = portid;
1150 skb_queue_head_init(&dest->q);
1151
1152 mutex_lock(&audit_filter_mutex);
1153 audit_list_rules(portid, seq, &dest->q);
1154 mutex_unlock(&audit_filter_mutex);
1155
1156 tsk = kthread_run(audit_send_list, dest, "audit_send_list");
1157 if (IS_ERR(tsk)) {
1158 skb_queue_purge(&dest->q);
1159 kfree(dest);
1160 err = PTR_ERR(tsk);
1161 }
1162
1163 return err;
1164}
1165
1166int audit_comparator(u32 left, u32 op, u32 right)
1167{
1168 switch (op) {
1169 case Audit_equal:
1170 return (left == right);
1171 case Audit_not_equal:
1172 return (left != right);
1173 case Audit_lt:
1174 return (left < right);
1175 case Audit_le:
1176 return (left <= right);
1177 case Audit_gt:
1178 return (left > right);
1179 case Audit_ge:
1180 return (left >= right);
1181 case Audit_bitmask:
1182 return (left & right);
1183 case Audit_bittest:
1184 return ((left & right) == right);
1185 default:
1186 BUG();
1187 return 0;
1188 }
1189}
1190
1191int audit_uid_comparator(kuid_t left, u32 op, kuid_t right)
1192{
1193 switch (op) {
1194 case Audit_equal:
1195 return uid_eq(left, right);
1196 case Audit_not_equal:
1197 return !uid_eq(left, right);
1198 case Audit_lt:
1199 return uid_lt(left, right);
1200 case Audit_le:
1201 return uid_lte(left, right);
1202 case Audit_gt:
1203 return uid_gt(left, right);
1204 case Audit_ge:
1205 return uid_gte(left, right);
1206 case Audit_bitmask:
1207 case Audit_bittest:
1208 default:
1209 BUG();
1210 return 0;
1211 }
1212}
1213
1214int audit_gid_comparator(kgid_t left, u32 op, kgid_t right)
1215{
1216 switch (op) {
1217 case Audit_equal:
1218 return gid_eq(left, right);
1219 case Audit_not_equal:
1220 return !gid_eq(left, right);
1221 case Audit_lt:
1222 return gid_lt(left, right);
1223 case Audit_le:
1224 return gid_lte(left, right);
1225 case Audit_gt:
1226 return gid_gt(left, right);
1227 case Audit_ge:
1228 return gid_gte(left, right);
1229 case Audit_bitmask:
1230 case Audit_bittest:
1231 default:
1232 BUG();
1233 return 0;
1234 }
1235}
1236
1237/**
1238 * parent_len - find the length of the parent portion of a pathname
1239 * @path: pathname of which to determine length
1240 */
1241int parent_len(const char *path)
1242{
1243 int plen;
1244 const char *p;
1245
1246 plen = strlen(path);
1247
1248 if (plen == 0)
1249 return plen;
1250
1251 /* disregard trailing slashes */
1252 p = path + plen - 1;
1253 while ((*p == '/') && (p > path))
1254 p--;
1255
1256 /* walk backward until we find the next slash or hit beginning */
1257 while ((*p != '/') && (p > path))
1258 p--;
1259
1260 /* did we find a slash? Then increment to include it in path */
1261 if (*p == '/')
1262 p++;
1263
1264 return p - path;
1265}
1266
1267/**
1268 * audit_compare_dname_path - compare given dentry name with last component in
1269 * given path. Return of 0 indicates a match.
1270 * @dname: dentry name that we're comparing
1271 * @path: full pathname that we're comparing
1272 * @parentlen: length of the parent if known. Passing in AUDIT_NAME_FULL
1273 * here indicates that we must compute this value.
1274 */
1275int audit_compare_dname_path(const char *dname, const char *path, int parentlen)
1276{
1277 int dlen, pathlen;
1278 const char *p;
1279
1280 dlen = strlen(dname);
1281 pathlen = strlen(path);
1282 if (pathlen < dlen)
1283 return 1;
1284
1285 parentlen = parentlen == AUDIT_NAME_FULL ? parent_len(path) : parentlen;
1286 if (pathlen - parentlen != dlen)
1287 return 1;
1288
1289 p = path + parentlen;
1290
1291 return strncmp(p, dname, dlen);
1292}
1293
1294int audit_filter(int msgtype, unsigned int listtype)
1295{
1296 struct audit_entry *e;
1297 int ret = 1; /* Audit by default */
1298
1299 rcu_read_lock();
1300 if (list_empty(&audit_filter_list[listtype]))
1301 goto unlock_and_return;
1302 list_for_each_entry_rcu(e, &audit_filter_list[listtype], list) {
1303 int i, result = 0;
1304
1305 for (i = 0; i < e->rule.field_count; i++) {
1306 struct audit_field *f = &e->rule.fields[i];
1307 pid_t pid;
1308 u32 sid;
1309
1310 switch (f->type) {
1311 case AUDIT_PID:
1312 pid = task_pid_nr(current);
1313 result = audit_comparator(pid, f->op, f->val);
1314 break;
1315 case AUDIT_UID:
1316 result = audit_uid_comparator(current_uid(), f->op, f->uid);
1317 break;
1318 case AUDIT_GID:
1319 result = audit_gid_comparator(current_gid(), f->op, f->gid);
1320 break;
1321 case AUDIT_LOGINUID:
1322 result = audit_uid_comparator(audit_get_loginuid(current),
1323 f->op, f->uid);
1324 break;
1325 case AUDIT_LOGINUID_SET:
1326 result = audit_comparator(audit_loginuid_set(current),
1327 f->op, f->val);
1328 break;
1329 case AUDIT_MSGTYPE:
1330 result = audit_comparator(msgtype, f->op, f->val);
1331 break;
1332 case AUDIT_SUBJ_USER:
1333 case AUDIT_SUBJ_ROLE:
1334 case AUDIT_SUBJ_TYPE:
1335 case AUDIT_SUBJ_SEN:
1336 case AUDIT_SUBJ_CLR:
1337 if (f->lsm_rule) {
1338 security_task_getsecid(current, &sid);
1339 result = security_audit_rule_match(sid,
1340 f->type, f->op, f->lsm_rule, NULL);
1341 }
1342 break;
1343 default:
1344 goto unlock_and_return;
1345 }
1346 if (result < 0) /* error */
1347 goto unlock_and_return;
1348 if (!result)
1349 break;
1350 }
1351 if (result > 0) {
1352 if (e->rule.action == AUDIT_NEVER || listtype == AUDIT_FILTER_TYPE)
1353 ret = 0;
1354 break;
1355 }
1356 }
1357unlock_and_return:
1358 rcu_read_unlock();
1359 return ret;
1360}
1361
1362static int update_lsm_rule(struct audit_krule *r)
1363{
1364 struct audit_entry *entry = container_of(r, struct audit_entry, rule);
1365 struct audit_entry *nentry;
1366 int err = 0;
1367
1368 if (!security_audit_rule_known(r))
1369 return 0;
1370
1371 nentry = audit_dupe_rule(r);
1372 if (entry->rule.exe)
1373 audit_remove_mark(entry->rule.exe);
1374 if (IS_ERR(nentry)) {
1375 /* save the first error encountered for the
1376 * return value */
1377 err = PTR_ERR(nentry);
1378 audit_panic("error updating LSM filters");
1379 if (r->watch)
1380 list_del(&r->rlist);
1381 list_del_rcu(&entry->list);
1382 list_del(&r->list);
1383 } else {
1384 if (r->watch || r->tree)
1385 list_replace_init(&r->rlist, &nentry->rule.rlist);
1386 list_replace_rcu(&entry->list, &nentry->list);
1387 list_replace(&r->list, &nentry->rule.list);
1388 }
1389 call_rcu(&entry->rcu, audit_free_rule_rcu);
1390
1391 return err;
1392}
1393
1394/* This function will re-initialize the lsm_rule field of all applicable rules.
1395 * It will traverse the filter lists serarching for rules that contain LSM
1396 * specific filter fields. When such a rule is found, it is copied, the
1397 * LSM field is re-initialized, and the old rule is replaced with the
1398 * updated rule. */
1399int audit_update_lsm_rules(void)
1400{
1401 struct audit_krule *r, *n;
1402 int i, err = 0;
1403
1404 /* audit_filter_mutex synchronizes the writers */
1405 mutex_lock(&audit_filter_mutex);
1406
1407 for (i = 0; i < AUDIT_NR_FILTERS; i++) {
1408 list_for_each_entry_safe(r, n, &audit_rules_list[i], list) {
1409 int res = update_lsm_rule(r);
1410 if (!err)
1411 err = res;
1412 }
1413 }
1414 mutex_unlock(&audit_filter_mutex);
1415
1416 return err;
1417}
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}