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1/* auditfilter.c -- filtering of audit events
2 *
3 * Copyright 2003-2004 Red Hat, Inc.
4 * Copyright 2005 Hewlett-Packard Development Company, L.P.
5 * Copyright 2005 IBM Corporation
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 */
21
22#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
23
24#include <linux/kernel.h>
25#include <linux/audit.h>
26#include <linux/kthread.h>
27#include <linux/mutex.h>
28#include <linux/fs.h>
29#include <linux/namei.h>
30#include <linux/netlink.h>
31#include <linux/sched.h>
32#include <linux/slab.h>
33#include <linux/security.h>
34#include <net/net_namespace.h>
35#include <net/sock.h>
36#include "audit.h"
37
38/*
39 * Locking model:
40 *
41 * audit_filter_mutex:
42 * Synchronizes writes and blocking reads of audit's filterlist
43 * data. Rcu is used to traverse the filterlist and access
44 * contents of structs audit_entry, audit_watch and opaque
45 * LSM rules during filtering. If modified, these structures
46 * must be copied and replace their counterparts in the filterlist.
47 * An audit_parent struct is not accessed during filtering, so may
48 * be written directly provided audit_filter_mutex is held.
49 */
50
51/* Audit filter lists, defined in <linux/audit.h> */
52struct list_head audit_filter_list[AUDIT_NR_FILTERS] = {
53 LIST_HEAD_INIT(audit_filter_list[0]),
54 LIST_HEAD_INIT(audit_filter_list[1]),
55 LIST_HEAD_INIT(audit_filter_list[2]),
56 LIST_HEAD_INIT(audit_filter_list[3]),
57 LIST_HEAD_INIT(audit_filter_list[4]),
58 LIST_HEAD_INIT(audit_filter_list[5]),
59#if AUDIT_NR_FILTERS != 6
60#error Fix audit_filter_list initialiser
61#endif
62};
63static struct list_head audit_rules_list[AUDIT_NR_FILTERS] = {
64 LIST_HEAD_INIT(audit_rules_list[0]),
65 LIST_HEAD_INIT(audit_rules_list[1]),
66 LIST_HEAD_INIT(audit_rules_list[2]),
67 LIST_HEAD_INIT(audit_rules_list[3]),
68 LIST_HEAD_INIT(audit_rules_list[4]),
69 LIST_HEAD_INIT(audit_rules_list[5]),
70};
71
72DEFINE_MUTEX(audit_filter_mutex);
73
74static 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 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_TYPE:
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_TYPE &&
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_equal)
430 return -EINVAL;
431 if (entry->rule.listnr != AUDIT_FILTER_EXIT)
432 return -EINVAL;
433 break;
434 }
435 return 0;
436}
437
438/* Translate struct audit_rule_data to kernel's rule representation. */
439static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
440 size_t datasz)
441{
442 int err = 0;
443 struct audit_entry *entry;
444 void *bufp;
445 size_t remain = datasz - sizeof(struct audit_rule_data);
446 int i;
447 char *str;
448 struct audit_fsnotify_mark *audit_mark;
449
450 entry = audit_to_entry_common(data);
451 if (IS_ERR(entry))
452 goto exit_nofree;
453
454 bufp = data->buf;
455 for (i = 0; i < data->field_count; i++) {
456 struct audit_field *f = &entry->rule.fields[i];
457
458 err = -EINVAL;
459
460 f->op = audit_to_op(data->fieldflags[i]);
461 if (f->op == Audit_bad)
462 goto exit_free;
463
464 f->type = data->fields[i];
465 f->val = data->values[i];
466
467 /* Support legacy tests for a valid loginuid */
468 if ((f->type == AUDIT_LOGINUID) && (f->val == AUDIT_UID_UNSET)) {
469 f->type = AUDIT_LOGINUID_SET;
470 f->val = 0;
471 entry->rule.pflags |= AUDIT_LOGINUID_LEGACY;
472 }
473
474 err = audit_field_valid(entry, f);
475 if (err)
476 goto exit_free;
477
478 err = -EINVAL;
479 switch (f->type) {
480 case AUDIT_LOGINUID:
481 case AUDIT_UID:
482 case AUDIT_EUID:
483 case AUDIT_SUID:
484 case AUDIT_FSUID:
485 case AUDIT_OBJ_UID:
486 f->uid = make_kuid(current_user_ns(), f->val);
487 if (!uid_valid(f->uid))
488 goto exit_free;
489 break;
490 case AUDIT_GID:
491 case AUDIT_EGID:
492 case AUDIT_SGID:
493 case AUDIT_FSGID:
494 case AUDIT_OBJ_GID:
495 f->gid = make_kgid(current_user_ns(), f->val);
496 if (!gid_valid(f->gid))
497 goto exit_free;
498 break;
499 case AUDIT_ARCH:
500 entry->rule.arch_f = f;
501 break;
502 case AUDIT_SUBJ_USER:
503 case AUDIT_SUBJ_ROLE:
504 case AUDIT_SUBJ_TYPE:
505 case AUDIT_SUBJ_SEN:
506 case AUDIT_SUBJ_CLR:
507 case AUDIT_OBJ_USER:
508 case AUDIT_OBJ_ROLE:
509 case AUDIT_OBJ_TYPE:
510 case AUDIT_OBJ_LEV_LOW:
511 case AUDIT_OBJ_LEV_HIGH:
512 str = audit_unpack_string(&bufp, &remain, f->val);
513 if (IS_ERR(str))
514 goto exit_free;
515 entry->rule.buflen += f->val;
516
517 err = security_audit_rule_init(f->type, f->op, str,
518 (void **)&f->lsm_rule);
519 /* Keep currently invalid fields around in case they
520 * become valid after a policy reload. */
521 if (err == -EINVAL) {
522 pr_warn("audit rule for LSM \'%s\' is invalid\n",
523 str);
524 err = 0;
525 }
526 if (err) {
527 kfree(str);
528 goto exit_free;
529 } else
530 f->lsm_str = str;
531 break;
532 case AUDIT_WATCH:
533 str = audit_unpack_string(&bufp, &remain, f->val);
534 if (IS_ERR(str))
535 goto exit_free;
536 entry->rule.buflen += f->val;
537
538 err = audit_to_watch(&entry->rule, str, f->val, f->op);
539 if (err) {
540 kfree(str);
541 goto exit_free;
542 }
543 break;
544 case AUDIT_DIR:
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
550 err = audit_make_tree(&entry->rule, str, f->op);
551 kfree(str);
552 if (err)
553 goto exit_free;
554 break;
555 case AUDIT_INODE:
556 err = audit_to_inode(&entry->rule, f);
557 if (err)
558 goto exit_free;
559 break;
560 case AUDIT_FILTERKEY:
561 if (entry->rule.filterkey || f->val > AUDIT_MAX_KEY_LEN)
562 goto exit_free;
563 str = audit_unpack_string(&bufp, &remain, f->val);
564 if (IS_ERR(str))
565 goto exit_free;
566 entry->rule.buflen += f->val;
567 entry->rule.filterkey = str;
568 break;
569 case AUDIT_EXE:
570 if (entry->rule.exe || f->val > PATH_MAX)
571 goto exit_free;
572 str = audit_unpack_string(&bufp, &remain, f->val);
573 if (IS_ERR(str)) {
574 err = PTR_ERR(str);
575 goto exit_free;
576 }
577 entry->rule.buflen += f->val;
578
579 audit_mark = audit_alloc_mark(&entry->rule, str, f->val);
580 if (IS_ERR(audit_mark)) {
581 kfree(str);
582 err = PTR_ERR(audit_mark);
583 goto exit_free;
584 }
585 entry->rule.exe = audit_mark;
586 break;
587 }
588 }
589
590 if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal)
591 entry->rule.inode_f = NULL;
592
593exit_nofree:
594 return entry;
595
596exit_free:
597 if (entry->rule.tree)
598 audit_put_tree(entry->rule.tree); /* that's the temporary one */
599 if (entry->rule.exe)
600 audit_remove_mark(entry->rule.exe); /* that's the template one */
601 audit_free_rule(entry);
602 return ERR_PTR(err);
603}
604
605/* Pack a filter field's string representation into data block. */
606static inline size_t audit_pack_string(void **bufp, const char *str)
607{
608 size_t len = strlen(str);
609
610 memcpy(*bufp, str, len);
611 *bufp += len;
612
613 return len;
614}
615
616/* Translate kernel rule representation to struct audit_rule_data. */
617static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule)
618{
619 struct audit_rule_data *data;
620 void *bufp;
621 int i;
622
623 data = kmalloc(sizeof(*data) + krule->buflen, GFP_KERNEL);
624 if (unlikely(!data))
625 return NULL;
626 memset(data, 0, sizeof(*data));
627
628 data->flags = krule->flags | krule->listnr;
629 data->action = krule->action;
630 data->field_count = krule->field_count;
631 bufp = data->buf;
632 for (i = 0; i < data->field_count; i++) {
633 struct audit_field *f = &krule->fields[i];
634
635 data->fields[i] = f->type;
636 data->fieldflags[i] = audit_ops[f->op];
637 switch(f->type) {
638 case AUDIT_SUBJ_USER:
639 case AUDIT_SUBJ_ROLE:
640 case AUDIT_SUBJ_TYPE:
641 case AUDIT_SUBJ_SEN:
642 case AUDIT_SUBJ_CLR:
643 case AUDIT_OBJ_USER:
644 case AUDIT_OBJ_ROLE:
645 case AUDIT_OBJ_TYPE:
646 case AUDIT_OBJ_LEV_LOW:
647 case AUDIT_OBJ_LEV_HIGH:
648 data->buflen += data->values[i] =
649 audit_pack_string(&bufp, f->lsm_str);
650 break;
651 case AUDIT_WATCH:
652 data->buflen += data->values[i] =
653 audit_pack_string(&bufp,
654 audit_watch_path(krule->watch));
655 break;
656 case AUDIT_DIR:
657 data->buflen += data->values[i] =
658 audit_pack_string(&bufp,
659 audit_tree_path(krule->tree));
660 break;
661 case AUDIT_FILTERKEY:
662 data->buflen += data->values[i] =
663 audit_pack_string(&bufp, krule->filterkey);
664 break;
665 case AUDIT_EXE:
666 data->buflen += data->values[i] =
667 audit_pack_string(&bufp, audit_mark_path(krule->exe));
668 break;
669 case AUDIT_LOGINUID_SET:
670 if (krule->pflags & AUDIT_LOGINUID_LEGACY && !f->val) {
671 data->fields[i] = AUDIT_LOGINUID;
672 data->values[i] = AUDIT_UID_UNSET;
673 break;
674 }
675 /* fallthrough if set */
676 default:
677 data->values[i] = f->val;
678 }
679 }
680 for (i = 0; i < AUDIT_BITMASK_SIZE; i++) data->mask[i] = krule->mask[i];
681
682 return data;
683}
684
685/* Compare two rules in kernel format. Considered success if rules
686 * don't match. */
687static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
688{
689 int i;
690
691 if (a->flags != b->flags ||
692 a->pflags != b->pflags ||
693 a->listnr != b->listnr ||
694 a->action != b->action ||
695 a->field_count != b->field_count)
696 return 1;
697
698 for (i = 0; i < a->field_count; i++) {
699 if (a->fields[i].type != b->fields[i].type ||
700 a->fields[i].op != b->fields[i].op)
701 return 1;
702
703 switch(a->fields[i].type) {
704 case AUDIT_SUBJ_USER:
705 case AUDIT_SUBJ_ROLE:
706 case AUDIT_SUBJ_TYPE:
707 case AUDIT_SUBJ_SEN:
708 case AUDIT_SUBJ_CLR:
709 case AUDIT_OBJ_USER:
710 case AUDIT_OBJ_ROLE:
711 case AUDIT_OBJ_TYPE:
712 case AUDIT_OBJ_LEV_LOW:
713 case AUDIT_OBJ_LEV_HIGH:
714 if (strcmp(a->fields[i].lsm_str, b->fields[i].lsm_str))
715 return 1;
716 break;
717 case AUDIT_WATCH:
718 if (strcmp(audit_watch_path(a->watch),
719 audit_watch_path(b->watch)))
720 return 1;
721 break;
722 case AUDIT_DIR:
723 if (strcmp(audit_tree_path(a->tree),
724 audit_tree_path(b->tree)))
725 return 1;
726 break;
727 case AUDIT_FILTERKEY:
728 /* both filterkeys exist based on above type compare */
729 if (strcmp(a->filterkey, b->filterkey))
730 return 1;
731 break;
732 case AUDIT_EXE:
733 /* both paths exist based on above type compare */
734 if (strcmp(audit_mark_path(a->exe),
735 audit_mark_path(b->exe)))
736 return 1;
737 break;
738 case AUDIT_UID:
739 case AUDIT_EUID:
740 case AUDIT_SUID:
741 case AUDIT_FSUID:
742 case AUDIT_LOGINUID:
743 case AUDIT_OBJ_UID:
744 if (!uid_eq(a->fields[i].uid, b->fields[i].uid))
745 return 1;
746 break;
747 case AUDIT_GID:
748 case AUDIT_EGID:
749 case AUDIT_SGID:
750 case AUDIT_FSGID:
751 case AUDIT_OBJ_GID:
752 if (!gid_eq(a->fields[i].gid, b->fields[i].gid))
753 return 1;
754 break;
755 default:
756 if (a->fields[i].val != b->fields[i].val)
757 return 1;
758 }
759 }
760
761 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
762 if (a->mask[i] != b->mask[i])
763 return 1;
764
765 return 0;
766}
767
768/* Duplicate LSM field information. The lsm_rule is opaque, so must be
769 * re-initialized. */
770static inline int audit_dupe_lsm_field(struct audit_field *df,
771 struct audit_field *sf)
772{
773 int ret = 0;
774 char *lsm_str;
775
776 /* our own copy of lsm_str */
777 lsm_str = kstrdup(sf->lsm_str, GFP_KERNEL);
778 if (unlikely(!lsm_str))
779 return -ENOMEM;
780 df->lsm_str = lsm_str;
781
782 /* our own (refreshed) copy of lsm_rule */
783 ret = security_audit_rule_init(df->type, df->op, df->lsm_str,
784 (void **)&df->lsm_rule);
785 /* Keep currently invalid fields around in case they
786 * become valid after a policy reload. */
787 if (ret == -EINVAL) {
788 pr_warn("audit rule for LSM \'%s\' is invalid\n",
789 df->lsm_str);
790 ret = 0;
791 }
792
793 return ret;
794}
795
796/* Duplicate an audit rule. This will be a deep copy with the exception
797 * of the watch - that pointer is carried over. The LSM specific fields
798 * will be updated in the copy. The point is to be able to replace the old
799 * rule with the new rule in the filterlist, then free the old rule.
800 * The rlist element is undefined; list manipulations are handled apart from
801 * the initial copy. */
802struct audit_entry *audit_dupe_rule(struct audit_krule *old)
803{
804 u32 fcount = old->field_count;
805 struct audit_entry *entry;
806 struct audit_krule *new;
807 char *fk;
808 int i, err = 0;
809
810 entry = audit_init_entry(fcount);
811 if (unlikely(!entry))
812 return ERR_PTR(-ENOMEM);
813
814 new = &entry->rule;
815 new->flags = old->flags;
816 new->pflags = old->pflags;
817 new->listnr = old->listnr;
818 new->action = old->action;
819 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
820 new->mask[i] = old->mask[i];
821 new->prio = old->prio;
822 new->buflen = old->buflen;
823 new->inode_f = old->inode_f;
824 new->field_count = old->field_count;
825
826 /*
827 * note that we are OK with not refcounting here; audit_match_tree()
828 * never dereferences tree and we can't get false positives there
829 * since we'd have to have rule gone from the list *and* removed
830 * before the chunks found by lookup had been allocated, i.e. before
831 * the beginning of list scan.
832 */
833 new->tree = old->tree;
834 memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount);
835
836 /* deep copy this information, updating the lsm_rule fields, because
837 * the originals will all be freed when the old rule is freed. */
838 for (i = 0; i < fcount; i++) {
839 switch (new->fields[i].type) {
840 case AUDIT_SUBJ_USER:
841 case AUDIT_SUBJ_ROLE:
842 case AUDIT_SUBJ_TYPE:
843 case AUDIT_SUBJ_SEN:
844 case AUDIT_SUBJ_CLR:
845 case AUDIT_OBJ_USER:
846 case AUDIT_OBJ_ROLE:
847 case AUDIT_OBJ_TYPE:
848 case AUDIT_OBJ_LEV_LOW:
849 case AUDIT_OBJ_LEV_HIGH:
850 err = audit_dupe_lsm_field(&new->fields[i],
851 &old->fields[i]);
852 break;
853 case AUDIT_FILTERKEY:
854 fk = kstrdup(old->filterkey, GFP_KERNEL);
855 if (unlikely(!fk))
856 err = -ENOMEM;
857 else
858 new->filterkey = fk;
859 break;
860 case AUDIT_EXE:
861 err = audit_dupe_exe(new, old);
862 break;
863 }
864 if (err) {
865 if (new->exe)
866 audit_remove_mark(new->exe);
867 audit_free_rule(entry);
868 return ERR_PTR(err);
869 }
870 }
871
872 if (old->watch) {
873 audit_get_watch(old->watch);
874 new->watch = old->watch;
875 }
876
877 return entry;
878}
879
880/* Find an existing audit rule.
881 * Caller must hold audit_filter_mutex to prevent stale rule data. */
882static struct audit_entry *audit_find_rule(struct audit_entry *entry,
883 struct list_head **p)
884{
885 struct audit_entry *e, *found = NULL;
886 struct list_head *list;
887 int h;
888
889 if (entry->rule.inode_f) {
890 h = audit_hash_ino(entry->rule.inode_f->val);
891 *p = list = &audit_inode_hash[h];
892 } else if (entry->rule.watch) {
893 /* we don't know the inode number, so must walk entire hash */
894 for (h = 0; h < AUDIT_INODE_BUCKETS; h++) {
895 list = &audit_inode_hash[h];
896 list_for_each_entry(e, list, list)
897 if (!audit_compare_rule(&entry->rule, &e->rule)) {
898 found = e;
899 goto out;
900 }
901 }
902 goto out;
903 } else {
904 *p = list = &audit_filter_list[entry->rule.listnr];
905 }
906
907 list_for_each_entry(e, list, list)
908 if (!audit_compare_rule(&entry->rule, &e->rule)) {
909 found = e;
910 goto out;
911 }
912
913out:
914 return found;
915}
916
917static u64 prio_low = ~0ULL/2;
918static u64 prio_high = ~0ULL/2 - 1;
919
920/* Add rule to given filterlist if not a duplicate. */
921static inline int audit_add_rule(struct audit_entry *entry)
922{
923 struct audit_entry *e;
924 struct audit_watch *watch = entry->rule.watch;
925 struct audit_tree *tree = entry->rule.tree;
926 struct list_head *list;
927 int err = 0;
928#ifdef CONFIG_AUDITSYSCALL
929 int dont_count = 0;
930
931 /* If any of these, don't count towards total */
932 switch(entry->rule.listnr) {
933 case AUDIT_FILTER_USER:
934 case AUDIT_FILTER_TYPE:
935 case AUDIT_FILTER_FS:
936 dont_count = 1;
937 }
938#endif
939
940 mutex_lock(&audit_filter_mutex);
941 e = audit_find_rule(entry, &list);
942 if (e) {
943 mutex_unlock(&audit_filter_mutex);
944 err = -EEXIST;
945 /* normally audit_add_tree_rule() will free it on failure */
946 if (tree)
947 audit_put_tree(tree);
948 return err;
949 }
950
951 if (watch) {
952 /* audit_filter_mutex is dropped and re-taken during this call */
953 err = audit_add_watch(&entry->rule, &list);
954 if (err) {
955 mutex_unlock(&audit_filter_mutex);
956 /*
957 * normally audit_add_tree_rule() will free it
958 * on failure
959 */
960 if (tree)
961 audit_put_tree(tree);
962 return err;
963 }
964 }
965 if (tree) {
966 err = audit_add_tree_rule(&entry->rule);
967 if (err) {
968 mutex_unlock(&audit_filter_mutex);
969 return err;
970 }
971 }
972
973 entry->rule.prio = ~0ULL;
974 if (entry->rule.listnr == AUDIT_FILTER_EXIT) {
975 if (entry->rule.flags & AUDIT_FILTER_PREPEND)
976 entry->rule.prio = ++prio_high;
977 else
978 entry->rule.prio = --prio_low;
979 }
980
981 if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
982 list_add(&entry->rule.list,
983 &audit_rules_list[entry->rule.listnr]);
984 list_add_rcu(&entry->list, list);
985 entry->rule.flags &= ~AUDIT_FILTER_PREPEND;
986 } else {
987 list_add_tail(&entry->rule.list,
988 &audit_rules_list[entry->rule.listnr]);
989 list_add_tail_rcu(&entry->list, list);
990 }
991#ifdef CONFIG_AUDITSYSCALL
992 if (!dont_count)
993 audit_n_rules++;
994
995 if (!audit_match_signal(entry))
996 audit_signals++;
997#endif
998 mutex_unlock(&audit_filter_mutex);
999
1000 return err;
1001}
1002
1003/* Remove an existing rule from filterlist. */
1004int audit_del_rule(struct audit_entry *entry)
1005{
1006 struct audit_entry *e;
1007 struct audit_tree *tree = entry->rule.tree;
1008 struct list_head *list;
1009 int ret = 0;
1010#ifdef CONFIG_AUDITSYSCALL
1011 int dont_count = 0;
1012
1013 /* If any of these, don't count towards total */
1014 switch(entry->rule.listnr) {
1015 case AUDIT_FILTER_USER:
1016 case AUDIT_FILTER_TYPE:
1017 case AUDIT_FILTER_FS:
1018 dont_count = 1;
1019 }
1020#endif
1021
1022 mutex_lock(&audit_filter_mutex);
1023 e = audit_find_rule(entry, &list);
1024 if (!e) {
1025 ret = -ENOENT;
1026 goto out;
1027 }
1028
1029 if (e->rule.watch)
1030 audit_remove_watch_rule(&e->rule);
1031
1032 if (e->rule.tree)
1033 audit_remove_tree_rule(&e->rule);
1034
1035 if (e->rule.exe)
1036 audit_remove_mark_rule(&e->rule);
1037
1038#ifdef CONFIG_AUDITSYSCALL
1039 if (!dont_count)
1040 audit_n_rules--;
1041
1042 if (!audit_match_signal(entry))
1043 audit_signals--;
1044#endif
1045
1046 list_del_rcu(&e->list);
1047 list_del(&e->rule.list);
1048 call_rcu(&e->rcu, audit_free_rule_rcu);
1049
1050out:
1051 mutex_unlock(&audit_filter_mutex);
1052
1053 if (tree)
1054 audit_put_tree(tree); /* that's the temporary one */
1055
1056 return ret;
1057}
1058
1059/* List rules using struct audit_rule_data. */
1060static void audit_list_rules(int seq, struct sk_buff_head *q)
1061{
1062 struct sk_buff *skb;
1063 struct audit_krule *r;
1064 int i;
1065
1066 /* This is a blocking read, so use audit_filter_mutex instead of rcu
1067 * iterator to sync with list writers. */
1068 for (i=0; i<AUDIT_NR_FILTERS; i++) {
1069 list_for_each_entry(r, &audit_rules_list[i], list) {
1070 struct audit_rule_data *data;
1071
1072 data = audit_krule_to_data(r);
1073 if (unlikely(!data))
1074 break;
1075 skb = audit_make_reply(seq, AUDIT_LIST_RULES, 0, 1,
1076 data,
1077 sizeof(*data) + data->buflen);
1078 if (skb)
1079 skb_queue_tail(q, skb);
1080 kfree(data);
1081 }
1082 }
1083 skb = audit_make_reply(seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);
1084 if (skb)
1085 skb_queue_tail(q, skb);
1086}
1087
1088/* Log rule additions and removals */
1089static void audit_log_rule_change(char *action, struct audit_krule *rule, int res)
1090{
1091 struct audit_buffer *ab;
1092 uid_t loginuid = from_kuid(&init_user_ns, audit_get_loginuid(current));
1093 unsigned int sessionid = audit_get_sessionid(current);
1094
1095 if (!audit_enabled)
1096 return;
1097
1098 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
1099 if (!ab)
1100 return;
1101 audit_log_format(ab, "auid=%u ses=%u" ,loginuid, sessionid);
1102 audit_log_task_context(ab);
1103 audit_log_format(ab, " op=%s", action);
1104 audit_log_key(ab, rule->filterkey);
1105 audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
1106 audit_log_end(ab);
1107}
1108
1109/**
1110 * audit_rule_change - apply all rules to the specified message type
1111 * @type: audit message type
1112 * @seq: netlink audit message sequence (serial) number
1113 * @data: payload data
1114 * @datasz: size of payload data
1115 */
1116int audit_rule_change(int type, int seq, void *data, size_t datasz)
1117{
1118 int err = 0;
1119 struct audit_entry *entry;
1120
1121 entry = audit_data_to_entry(data, datasz);
1122 if (IS_ERR(entry))
1123 return PTR_ERR(entry);
1124
1125 switch (type) {
1126 case AUDIT_ADD_RULE:
1127 err = audit_add_rule(entry);
1128 audit_log_rule_change("add_rule", &entry->rule, !err);
1129 break;
1130 case AUDIT_DEL_RULE:
1131 err = audit_del_rule(entry);
1132 audit_log_rule_change("remove_rule", &entry->rule, !err);
1133 break;
1134 default:
1135 err = -EINVAL;
1136 WARN_ON(1);
1137 }
1138
1139 if (err || type == AUDIT_DEL_RULE) {
1140 if (entry->rule.exe)
1141 audit_remove_mark(entry->rule.exe);
1142 audit_free_rule(entry);
1143 }
1144
1145 return err;
1146}
1147
1148/**
1149 * audit_list_rules_send - list the audit rules
1150 * @request_skb: skb of request we are replying to (used to target the reply)
1151 * @seq: netlink audit message sequence (serial) number
1152 */
1153int audit_list_rules_send(struct sk_buff *request_skb, int seq)
1154{
1155 u32 portid = NETLINK_CB(request_skb).portid;
1156 struct net *net = sock_net(NETLINK_CB(request_skb).sk);
1157 struct task_struct *tsk;
1158 struct audit_netlink_list *dest;
1159 int err = 0;
1160
1161 /* We can't just spew out the rules here because we might fill
1162 * the available socket buffer space and deadlock waiting for
1163 * auditctl to read from it... which isn't ever going to
1164 * happen if we're actually running in the context of auditctl
1165 * trying to _send_ the stuff */
1166
1167 dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL);
1168 if (!dest)
1169 return -ENOMEM;
1170 dest->net = get_net(net);
1171 dest->portid = portid;
1172 skb_queue_head_init(&dest->q);
1173
1174 mutex_lock(&audit_filter_mutex);
1175 audit_list_rules(seq, &dest->q);
1176 mutex_unlock(&audit_filter_mutex);
1177
1178 tsk = kthread_run(audit_send_list, dest, "audit_send_list");
1179 if (IS_ERR(tsk)) {
1180 skb_queue_purge(&dest->q);
1181 kfree(dest);
1182 err = PTR_ERR(tsk);
1183 }
1184
1185 return err;
1186}
1187
1188int audit_comparator(u32 left, u32 op, u32 right)
1189{
1190 switch (op) {
1191 case Audit_equal:
1192 return (left == right);
1193 case Audit_not_equal:
1194 return (left != right);
1195 case Audit_lt:
1196 return (left < right);
1197 case Audit_le:
1198 return (left <= right);
1199 case Audit_gt:
1200 return (left > right);
1201 case Audit_ge:
1202 return (left >= right);
1203 case Audit_bitmask:
1204 return (left & right);
1205 case Audit_bittest:
1206 return ((left & right) == right);
1207 default:
1208 BUG();
1209 return 0;
1210 }
1211}
1212
1213int audit_uid_comparator(kuid_t left, u32 op, kuid_t right)
1214{
1215 switch (op) {
1216 case Audit_equal:
1217 return uid_eq(left, right);
1218 case Audit_not_equal:
1219 return !uid_eq(left, right);
1220 case Audit_lt:
1221 return uid_lt(left, right);
1222 case Audit_le:
1223 return uid_lte(left, right);
1224 case Audit_gt:
1225 return uid_gt(left, right);
1226 case Audit_ge:
1227 return uid_gte(left, right);
1228 case Audit_bitmask:
1229 case Audit_bittest:
1230 default:
1231 BUG();
1232 return 0;
1233 }
1234}
1235
1236int audit_gid_comparator(kgid_t left, u32 op, kgid_t right)
1237{
1238 switch (op) {
1239 case Audit_equal:
1240 return gid_eq(left, right);
1241 case Audit_not_equal:
1242 return !gid_eq(left, right);
1243 case Audit_lt:
1244 return gid_lt(left, right);
1245 case Audit_le:
1246 return gid_lte(left, right);
1247 case Audit_gt:
1248 return gid_gt(left, right);
1249 case Audit_ge:
1250 return gid_gte(left, right);
1251 case Audit_bitmask:
1252 case Audit_bittest:
1253 default:
1254 BUG();
1255 return 0;
1256 }
1257}
1258
1259/**
1260 * parent_len - find the length of the parent portion of a pathname
1261 * @path: pathname of which to determine length
1262 */
1263int parent_len(const char *path)
1264{
1265 int plen;
1266 const char *p;
1267
1268 plen = strlen(path);
1269
1270 if (plen == 0)
1271 return plen;
1272
1273 /* disregard trailing slashes */
1274 p = path + plen - 1;
1275 while ((*p == '/') && (p > path))
1276 p--;
1277
1278 /* walk backward until we find the next slash or hit beginning */
1279 while ((*p != '/') && (p > path))
1280 p--;
1281
1282 /* did we find a slash? Then increment to include it in path */
1283 if (*p == '/')
1284 p++;
1285
1286 return p - path;
1287}
1288
1289/**
1290 * audit_compare_dname_path - compare given dentry name with last component in
1291 * given path. Return of 0 indicates a match.
1292 * @dname: dentry name that we're comparing
1293 * @path: full pathname that we're comparing
1294 * @parentlen: length of the parent if known. Passing in AUDIT_NAME_FULL
1295 * here indicates that we must compute this value.
1296 */
1297int audit_compare_dname_path(const char *dname, const char *path, int parentlen)
1298{
1299 int dlen, pathlen;
1300 const char *p;
1301
1302 dlen = strlen(dname);
1303 pathlen = strlen(path);
1304 if (pathlen < dlen)
1305 return 1;
1306
1307 parentlen = parentlen == AUDIT_NAME_FULL ? parent_len(path) : parentlen;
1308 if (pathlen - parentlen != dlen)
1309 return 1;
1310
1311 p = path + parentlen;
1312
1313 return strncmp(p, dname, dlen);
1314}
1315
1316int audit_filter(int msgtype, unsigned int listtype)
1317{
1318 struct audit_entry *e;
1319 int ret = 1; /* Audit by default */
1320
1321 rcu_read_lock();
1322 if (list_empty(&audit_filter_list[listtype]))
1323 goto unlock_and_return;
1324 list_for_each_entry_rcu(e, &audit_filter_list[listtype], list) {
1325 int i, result = 0;
1326
1327 for (i = 0; i < e->rule.field_count; i++) {
1328 struct audit_field *f = &e->rule.fields[i];
1329 pid_t pid;
1330 u32 sid;
1331
1332 switch (f->type) {
1333 case AUDIT_PID:
1334 pid = task_pid_nr(current);
1335 result = audit_comparator(pid, f->op, f->val);
1336 break;
1337 case AUDIT_UID:
1338 result = audit_uid_comparator(current_uid(), f->op, f->uid);
1339 break;
1340 case AUDIT_GID:
1341 result = audit_gid_comparator(current_gid(), f->op, f->gid);
1342 break;
1343 case AUDIT_LOGINUID:
1344 result = audit_uid_comparator(audit_get_loginuid(current),
1345 f->op, f->uid);
1346 break;
1347 case AUDIT_LOGINUID_SET:
1348 result = audit_comparator(audit_loginuid_set(current),
1349 f->op, f->val);
1350 break;
1351 case AUDIT_MSGTYPE:
1352 result = audit_comparator(msgtype, f->op, f->val);
1353 break;
1354 case AUDIT_SUBJ_USER:
1355 case AUDIT_SUBJ_ROLE:
1356 case AUDIT_SUBJ_TYPE:
1357 case AUDIT_SUBJ_SEN:
1358 case AUDIT_SUBJ_CLR:
1359 if (f->lsm_rule) {
1360 security_task_getsecid(current, &sid);
1361 result = security_audit_rule_match(sid,
1362 f->type, f->op, f->lsm_rule, NULL);
1363 }
1364 break;
1365 default:
1366 goto unlock_and_return;
1367 }
1368 if (result < 0) /* error */
1369 goto unlock_and_return;
1370 if (!result)
1371 break;
1372 }
1373 if (result > 0) {
1374 if (e->rule.action == AUDIT_NEVER || listtype == AUDIT_FILTER_TYPE)
1375 ret = 0;
1376 break;
1377 }
1378 }
1379unlock_and_return:
1380 rcu_read_unlock();
1381 return ret;
1382}
1383
1384static int update_lsm_rule(struct audit_krule *r)
1385{
1386 struct audit_entry *entry = container_of(r, struct audit_entry, rule);
1387 struct audit_entry *nentry;
1388 int err = 0;
1389
1390 if (!security_audit_rule_known(r))
1391 return 0;
1392
1393 nentry = audit_dupe_rule(r);
1394 if (entry->rule.exe)
1395 audit_remove_mark(entry->rule.exe);
1396 if (IS_ERR(nentry)) {
1397 /* save the first error encountered for the
1398 * return value */
1399 err = PTR_ERR(nentry);
1400 audit_panic("error updating LSM filters");
1401 if (r->watch)
1402 list_del(&r->rlist);
1403 list_del_rcu(&entry->list);
1404 list_del(&r->list);
1405 } else {
1406 if (r->watch || r->tree)
1407 list_replace_init(&r->rlist, &nentry->rule.rlist);
1408 list_replace_rcu(&entry->list, &nentry->list);
1409 list_replace(&r->list, &nentry->rule.list);
1410 }
1411 call_rcu(&entry->rcu, audit_free_rule_rcu);
1412
1413 return err;
1414}
1415
1416/* This function will re-initialize the lsm_rule field of all applicable rules.
1417 * It will traverse the filter lists serarching for rules that contain LSM
1418 * specific filter fields. When such a rule is found, it is copied, the
1419 * LSM field is re-initialized, and the old rule is replaced with the
1420 * updated rule. */
1421int audit_update_lsm_rules(void)
1422{
1423 struct audit_krule *r, *n;
1424 int i, err = 0;
1425
1426 /* audit_filter_mutex synchronizes the writers */
1427 mutex_lock(&audit_filter_mutex);
1428
1429 for (i = 0; i < AUDIT_NR_FILTERS; i++) {
1430 list_for_each_entry_safe(r, n, &audit_rules_list[i], list) {
1431 int res = update_lsm_rule(r);
1432 if (!err)
1433 err = res;
1434 }
1435 }
1436 mutex_unlock(&audit_filter_mutex);
1437
1438 return err;
1439}