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x86, mm: Change cachemode exports to non-gpl
[deliverable/linux.git] / kernel / auditfilter.c
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> */
52 struct 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 };
63 static 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
72 DEFINE_MUTEX(audit_filter_mutex);
73
74 static 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
92 static 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
108 void 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. */
115 static 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. */
136 char *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 respresentation. */
162 static 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
174 static __u32 *classes[AUDIT_SYSCALL_CLASSES];
175
176 int __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
197 int 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
207 static 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
219 static 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. */
246 static 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
308 exit_err:
309 return ERR_PTR(err);
310 }
311
312 static 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
324 static 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 */
333 static 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 /* bit ops are only useful on syscall args */
367 if (f->op == Audit_bitmask || f->op == Audit_bittest)
368 return -EINVAL;
369 break;
370 case AUDIT_ARG0:
371 case AUDIT_ARG1:
372 case AUDIT_ARG2:
373 case AUDIT_ARG3:
374 case AUDIT_SUBJ_USER:
375 case AUDIT_SUBJ_ROLE:
376 case AUDIT_SUBJ_TYPE:
377 case AUDIT_SUBJ_SEN:
378 case AUDIT_SUBJ_CLR:
379 case AUDIT_OBJ_USER:
380 case AUDIT_OBJ_ROLE:
381 case AUDIT_OBJ_TYPE:
382 case AUDIT_OBJ_LEV_LOW:
383 case AUDIT_OBJ_LEV_HIGH:
384 case AUDIT_WATCH:
385 case AUDIT_DIR:
386 case AUDIT_FILTERKEY:
387 break;
388 case AUDIT_LOGINUID_SET:
389 if ((f->val != 0) && (f->val != 1))
390 return -EINVAL;
391 /* FALL THROUGH */
392 case AUDIT_ARCH:
393 if (f->op != Audit_not_equal && f->op != Audit_equal)
394 return -EINVAL;
395 break;
396 case AUDIT_PERM:
397 if (f->val & ~15)
398 return -EINVAL;
399 break;
400 case AUDIT_FILETYPE:
401 if (f->val & ~S_IFMT)
402 return -EINVAL;
403 break;
404 case AUDIT_FIELD_COMPARE:
405 if (f->val > AUDIT_MAX_FIELD_COMPARE)
406 return -EINVAL;
407 break;
408 };
409 return 0;
410 }
411
412 /* Translate struct audit_rule_data to kernel's rule respresentation. */
413 static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
414 size_t datasz)
415 {
416 int err = 0;
417 struct audit_entry *entry;
418 void *bufp;
419 size_t remain = datasz - sizeof(struct audit_rule_data);
420 int i;
421 char *str;
422
423 entry = audit_to_entry_common(data);
424 if (IS_ERR(entry))
425 goto exit_nofree;
426
427 bufp = data->buf;
428 entry->rule.vers_ops = 2;
429 for (i = 0; i < data->field_count; i++) {
430 struct audit_field *f = &entry->rule.fields[i];
431
432 err = -EINVAL;
433
434 f->op = audit_to_op(data->fieldflags[i]);
435 if (f->op == Audit_bad)
436 goto exit_free;
437
438 f->type = data->fields[i];
439 f->val = data->values[i];
440
441 /* Support legacy tests for a valid loginuid */
442 if ((f->type == AUDIT_LOGINUID) && (f->val == AUDIT_UID_UNSET)) {
443 f->type = AUDIT_LOGINUID_SET;
444 f->val = 0;
445 entry->rule.pflags |= AUDIT_LOGINUID_LEGACY;
446 }
447
448 err = audit_field_valid(entry, f);
449 if (err)
450 goto exit_free;
451
452 err = -EINVAL;
453 switch (f->type) {
454 case AUDIT_LOGINUID:
455 case AUDIT_UID:
456 case AUDIT_EUID:
457 case AUDIT_SUID:
458 case AUDIT_FSUID:
459 case AUDIT_OBJ_UID:
460 f->uid = make_kuid(current_user_ns(), f->val);
461 if (!uid_valid(f->uid))
462 goto exit_free;
463 break;
464 case AUDIT_GID:
465 case AUDIT_EGID:
466 case AUDIT_SGID:
467 case AUDIT_FSGID:
468 case AUDIT_OBJ_GID:
469 f->gid = make_kgid(current_user_ns(), f->val);
470 if (!gid_valid(f->gid))
471 goto exit_free;
472 break;
473 case AUDIT_ARCH:
474 entry->rule.arch_f = f;
475 break;
476 case AUDIT_SUBJ_USER:
477 case AUDIT_SUBJ_ROLE:
478 case AUDIT_SUBJ_TYPE:
479 case AUDIT_SUBJ_SEN:
480 case AUDIT_SUBJ_CLR:
481 case AUDIT_OBJ_USER:
482 case AUDIT_OBJ_ROLE:
483 case AUDIT_OBJ_TYPE:
484 case AUDIT_OBJ_LEV_LOW:
485 case AUDIT_OBJ_LEV_HIGH:
486 str = audit_unpack_string(&bufp, &remain, f->val);
487 if (IS_ERR(str))
488 goto exit_free;
489 entry->rule.buflen += f->val;
490
491 err = security_audit_rule_init(f->type, f->op, str,
492 (void **)&f->lsm_rule);
493 /* Keep currently invalid fields around in case they
494 * become valid after a policy reload. */
495 if (err == -EINVAL) {
496 pr_warn("audit rule for LSM \'%s\' is invalid\n",
497 str);
498 err = 0;
499 }
500 if (err) {
501 kfree(str);
502 goto exit_free;
503 } else
504 f->lsm_str = str;
505 break;
506 case AUDIT_WATCH:
507 str = audit_unpack_string(&bufp, &remain, f->val);
508 if (IS_ERR(str))
509 goto exit_free;
510 entry->rule.buflen += f->val;
511
512 err = audit_to_watch(&entry->rule, str, f->val, f->op);
513 if (err) {
514 kfree(str);
515 goto exit_free;
516 }
517 break;
518 case AUDIT_DIR:
519 str = audit_unpack_string(&bufp, &remain, f->val);
520 if (IS_ERR(str))
521 goto exit_free;
522 entry->rule.buflen += f->val;
523
524 err = audit_make_tree(&entry->rule, str, f->op);
525 kfree(str);
526 if (err)
527 goto exit_free;
528 break;
529 case AUDIT_INODE:
530 err = audit_to_inode(&entry->rule, f);
531 if (err)
532 goto exit_free;
533 break;
534 case AUDIT_FILTERKEY:
535 if (entry->rule.filterkey || f->val > AUDIT_MAX_KEY_LEN)
536 goto exit_free;
537 str = audit_unpack_string(&bufp, &remain, f->val);
538 if (IS_ERR(str))
539 goto exit_free;
540 entry->rule.buflen += f->val;
541 entry->rule.filterkey = str;
542 break;
543 }
544 }
545
546 if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal)
547 entry->rule.inode_f = NULL;
548
549 exit_nofree:
550 return entry;
551
552 exit_free:
553 if (entry->rule.watch)
554 audit_put_watch(entry->rule.watch); /* matches initial get */
555 if (entry->rule.tree)
556 audit_put_tree(entry->rule.tree); /* that's the temporary one */
557 audit_free_rule(entry);
558 return ERR_PTR(err);
559 }
560
561 /* Pack a filter field's string representation into data block. */
562 static inline size_t audit_pack_string(void **bufp, const char *str)
563 {
564 size_t len = strlen(str);
565
566 memcpy(*bufp, str, len);
567 *bufp += len;
568
569 return len;
570 }
571
572 /* Translate kernel rule respresentation to struct audit_rule_data. */
573 static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule)
574 {
575 struct audit_rule_data *data;
576 void *bufp;
577 int i;
578
579 data = kmalloc(sizeof(*data) + krule->buflen, GFP_KERNEL);
580 if (unlikely(!data))
581 return NULL;
582 memset(data, 0, sizeof(*data));
583
584 data->flags = krule->flags | krule->listnr;
585 data->action = krule->action;
586 data->field_count = krule->field_count;
587 bufp = data->buf;
588 for (i = 0; i < data->field_count; i++) {
589 struct audit_field *f = &krule->fields[i];
590
591 data->fields[i] = f->type;
592 data->fieldflags[i] = audit_ops[f->op];
593 switch(f->type) {
594 case AUDIT_SUBJ_USER:
595 case AUDIT_SUBJ_ROLE:
596 case AUDIT_SUBJ_TYPE:
597 case AUDIT_SUBJ_SEN:
598 case AUDIT_SUBJ_CLR:
599 case AUDIT_OBJ_USER:
600 case AUDIT_OBJ_ROLE:
601 case AUDIT_OBJ_TYPE:
602 case AUDIT_OBJ_LEV_LOW:
603 case AUDIT_OBJ_LEV_HIGH:
604 data->buflen += data->values[i] =
605 audit_pack_string(&bufp, f->lsm_str);
606 break;
607 case AUDIT_WATCH:
608 data->buflen += data->values[i] =
609 audit_pack_string(&bufp,
610 audit_watch_path(krule->watch));
611 break;
612 case AUDIT_DIR:
613 data->buflen += data->values[i] =
614 audit_pack_string(&bufp,
615 audit_tree_path(krule->tree));
616 break;
617 case AUDIT_FILTERKEY:
618 data->buflen += data->values[i] =
619 audit_pack_string(&bufp, krule->filterkey);
620 break;
621 case AUDIT_LOGINUID_SET:
622 if (krule->pflags & AUDIT_LOGINUID_LEGACY && !f->val) {
623 data->fields[i] = AUDIT_LOGINUID;
624 data->values[i] = AUDIT_UID_UNSET;
625 break;
626 }
627 /* fallthrough if set */
628 default:
629 data->values[i] = f->val;
630 }
631 }
632 for (i = 0; i < AUDIT_BITMASK_SIZE; i++) data->mask[i] = krule->mask[i];
633
634 return data;
635 }
636
637 /* Compare two rules in kernel format. Considered success if rules
638 * don't match. */
639 static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
640 {
641 int i;
642
643 if (a->flags != b->flags ||
644 a->pflags != b->pflags ||
645 a->listnr != b->listnr ||
646 a->action != b->action ||
647 a->field_count != b->field_count)
648 return 1;
649
650 for (i = 0; i < a->field_count; i++) {
651 if (a->fields[i].type != b->fields[i].type ||
652 a->fields[i].op != b->fields[i].op)
653 return 1;
654
655 switch(a->fields[i].type) {
656 case AUDIT_SUBJ_USER:
657 case AUDIT_SUBJ_ROLE:
658 case AUDIT_SUBJ_TYPE:
659 case AUDIT_SUBJ_SEN:
660 case AUDIT_SUBJ_CLR:
661 case AUDIT_OBJ_USER:
662 case AUDIT_OBJ_ROLE:
663 case AUDIT_OBJ_TYPE:
664 case AUDIT_OBJ_LEV_LOW:
665 case AUDIT_OBJ_LEV_HIGH:
666 if (strcmp(a->fields[i].lsm_str, b->fields[i].lsm_str))
667 return 1;
668 break;
669 case AUDIT_WATCH:
670 if (strcmp(audit_watch_path(a->watch),
671 audit_watch_path(b->watch)))
672 return 1;
673 break;
674 case AUDIT_DIR:
675 if (strcmp(audit_tree_path(a->tree),
676 audit_tree_path(b->tree)))
677 return 1;
678 break;
679 case AUDIT_FILTERKEY:
680 /* both filterkeys exist based on above type compare */
681 if (strcmp(a->filterkey, b->filterkey))
682 return 1;
683 break;
684 case AUDIT_UID:
685 case AUDIT_EUID:
686 case AUDIT_SUID:
687 case AUDIT_FSUID:
688 case AUDIT_LOGINUID:
689 case AUDIT_OBJ_UID:
690 if (!uid_eq(a->fields[i].uid, b->fields[i].uid))
691 return 1;
692 break;
693 case AUDIT_GID:
694 case AUDIT_EGID:
695 case AUDIT_SGID:
696 case AUDIT_FSGID:
697 case AUDIT_OBJ_GID:
698 if (!gid_eq(a->fields[i].gid, b->fields[i].gid))
699 return 1;
700 break;
701 default:
702 if (a->fields[i].val != b->fields[i].val)
703 return 1;
704 }
705 }
706
707 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
708 if (a->mask[i] != b->mask[i])
709 return 1;
710
711 return 0;
712 }
713
714 /* Duplicate LSM field information. The lsm_rule is opaque, so must be
715 * re-initialized. */
716 static inline int audit_dupe_lsm_field(struct audit_field *df,
717 struct audit_field *sf)
718 {
719 int ret = 0;
720 char *lsm_str;
721
722 /* our own copy of lsm_str */
723 lsm_str = kstrdup(sf->lsm_str, GFP_KERNEL);
724 if (unlikely(!lsm_str))
725 return -ENOMEM;
726 df->lsm_str = lsm_str;
727
728 /* our own (refreshed) copy of lsm_rule */
729 ret = security_audit_rule_init(df->type, df->op, df->lsm_str,
730 (void **)&df->lsm_rule);
731 /* Keep currently invalid fields around in case they
732 * become valid after a policy reload. */
733 if (ret == -EINVAL) {
734 pr_warn("audit rule for LSM \'%s\' is invalid\n",
735 df->lsm_str);
736 ret = 0;
737 }
738
739 return ret;
740 }
741
742 /* Duplicate an audit rule. This will be a deep copy with the exception
743 * of the watch - that pointer is carried over. The LSM specific fields
744 * will be updated in the copy. The point is to be able to replace the old
745 * rule with the new rule in the filterlist, then free the old rule.
746 * The rlist element is undefined; list manipulations are handled apart from
747 * the initial copy. */
748 struct audit_entry *audit_dupe_rule(struct audit_krule *old)
749 {
750 u32 fcount = old->field_count;
751 struct audit_entry *entry;
752 struct audit_krule *new;
753 char *fk;
754 int i, err = 0;
755
756 entry = audit_init_entry(fcount);
757 if (unlikely(!entry))
758 return ERR_PTR(-ENOMEM);
759
760 new = &entry->rule;
761 new->vers_ops = old->vers_ops;
762 new->flags = old->flags;
763 new->pflags = old->pflags;
764 new->listnr = old->listnr;
765 new->action = old->action;
766 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
767 new->mask[i] = old->mask[i];
768 new->prio = old->prio;
769 new->buflen = old->buflen;
770 new->inode_f = old->inode_f;
771 new->field_count = old->field_count;
772
773 /*
774 * note that we are OK with not refcounting here; audit_match_tree()
775 * never dereferences tree and we can't get false positives there
776 * since we'd have to have rule gone from the list *and* removed
777 * before the chunks found by lookup had been allocated, i.e. before
778 * the beginning of list scan.
779 */
780 new->tree = old->tree;
781 memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount);
782
783 /* deep copy this information, updating the lsm_rule fields, because
784 * the originals will all be freed when the old rule is freed. */
785 for (i = 0; i < fcount; i++) {
786 switch (new->fields[i].type) {
787 case AUDIT_SUBJ_USER:
788 case AUDIT_SUBJ_ROLE:
789 case AUDIT_SUBJ_TYPE:
790 case AUDIT_SUBJ_SEN:
791 case AUDIT_SUBJ_CLR:
792 case AUDIT_OBJ_USER:
793 case AUDIT_OBJ_ROLE:
794 case AUDIT_OBJ_TYPE:
795 case AUDIT_OBJ_LEV_LOW:
796 case AUDIT_OBJ_LEV_HIGH:
797 err = audit_dupe_lsm_field(&new->fields[i],
798 &old->fields[i]);
799 break;
800 case AUDIT_FILTERKEY:
801 fk = kstrdup(old->filterkey, GFP_KERNEL);
802 if (unlikely(!fk))
803 err = -ENOMEM;
804 else
805 new->filterkey = fk;
806 }
807 if (err) {
808 audit_free_rule(entry);
809 return ERR_PTR(err);
810 }
811 }
812
813 if (old->watch) {
814 audit_get_watch(old->watch);
815 new->watch = old->watch;
816 }
817
818 return entry;
819 }
820
821 /* Find an existing audit rule.
822 * Caller must hold audit_filter_mutex to prevent stale rule data. */
823 static struct audit_entry *audit_find_rule(struct audit_entry *entry,
824 struct list_head **p)
825 {
826 struct audit_entry *e, *found = NULL;
827 struct list_head *list;
828 int h;
829
830 if (entry->rule.inode_f) {
831 h = audit_hash_ino(entry->rule.inode_f->val);
832 *p = list = &audit_inode_hash[h];
833 } else if (entry->rule.watch) {
834 /* we don't know the inode number, so must walk entire hash */
835 for (h = 0; h < AUDIT_INODE_BUCKETS; h++) {
836 list = &audit_inode_hash[h];
837 list_for_each_entry(e, list, list)
838 if (!audit_compare_rule(&entry->rule, &e->rule)) {
839 found = e;
840 goto out;
841 }
842 }
843 goto out;
844 } else {
845 *p = list = &audit_filter_list[entry->rule.listnr];
846 }
847
848 list_for_each_entry(e, list, list)
849 if (!audit_compare_rule(&entry->rule, &e->rule)) {
850 found = e;
851 goto out;
852 }
853
854 out:
855 return found;
856 }
857
858 static u64 prio_low = ~0ULL/2;
859 static u64 prio_high = ~0ULL/2 - 1;
860
861 /* Add rule to given filterlist if not a duplicate. */
862 static inline int audit_add_rule(struct audit_entry *entry)
863 {
864 struct audit_entry *e;
865 struct audit_watch *watch = entry->rule.watch;
866 struct audit_tree *tree = entry->rule.tree;
867 struct list_head *list;
868 int err;
869 #ifdef CONFIG_AUDITSYSCALL
870 int dont_count = 0;
871
872 /* If either of these, don't count towards total */
873 if (entry->rule.listnr == AUDIT_FILTER_USER ||
874 entry->rule.listnr == AUDIT_FILTER_TYPE)
875 dont_count = 1;
876 #endif
877
878 mutex_lock(&audit_filter_mutex);
879 e = audit_find_rule(entry, &list);
880 if (e) {
881 mutex_unlock(&audit_filter_mutex);
882 err = -EEXIST;
883 /* normally audit_add_tree_rule() will free it on failure */
884 if (tree)
885 audit_put_tree(tree);
886 goto error;
887 }
888
889 if (watch) {
890 /* audit_filter_mutex is dropped and re-taken during this call */
891 err = audit_add_watch(&entry->rule, &list);
892 if (err) {
893 mutex_unlock(&audit_filter_mutex);
894 /*
895 * normally audit_add_tree_rule() will free it
896 * on failure
897 */
898 if (tree)
899 audit_put_tree(tree);
900 goto error;
901 }
902 }
903 if (tree) {
904 err = audit_add_tree_rule(&entry->rule);
905 if (err) {
906 mutex_unlock(&audit_filter_mutex);
907 goto error;
908 }
909 }
910
911 entry->rule.prio = ~0ULL;
912 if (entry->rule.listnr == AUDIT_FILTER_EXIT) {
913 if (entry->rule.flags & AUDIT_FILTER_PREPEND)
914 entry->rule.prio = ++prio_high;
915 else
916 entry->rule.prio = --prio_low;
917 }
918
919 if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
920 list_add(&entry->rule.list,
921 &audit_rules_list[entry->rule.listnr]);
922 list_add_rcu(&entry->list, list);
923 entry->rule.flags &= ~AUDIT_FILTER_PREPEND;
924 } else {
925 list_add_tail(&entry->rule.list,
926 &audit_rules_list[entry->rule.listnr]);
927 list_add_tail_rcu(&entry->list, list);
928 }
929 #ifdef CONFIG_AUDITSYSCALL
930 if (!dont_count)
931 audit_n_rules++;
932
933 if (!audit_match_signal(entry))
934 audit_signals++;
935 #endif
936 mutex_unlock(&audit_filter_mutex);
937
938 return 0;
939
940 error:
941 if (watch)
942 audit_put_watch(watch); /* tmp watch, matches initial get */
943 return err;
944 }
945
946 /* Remove an existing rule from filterlist. */
947 static inline int audit_del_rule(struct audit_entry *entry)
948 {
949 struct audit_entry *e;
950 struct audit_watch *watch = entry->rule.watch;
951 struct audit_tree *tree = entry->rule.tree;
952 struct list_head *list;
953 int ret = 0;
954 #ifdef CONFIG_AUDITSYSCALL
955 int dont_count = 0;
956
957 /* If either of these, don't count towards total */
958 if (entry->rule.listnr == AUDIT_FILTER_USER ||
959 entry->rule.listnr == AUDIT_FILTER_TYPE)
960 dont_count = 1;
961 #endif
962
963 mutex_lock(&audit_filter_mutex);
964 e = audit_find_rule(entry, &list);
965 if (!e) {
966 mutex_unlock(&audit_filter_mutex);
967 ret = -ENOENT;
968 goto out;
969 }
970
971 if (e->rule.watch)
972 audit_remove_watch_rule(&e->rule);
973
974 if (e->rule.tree)
975 audit_remove_tree_rule(&e->rule);
976
977 list_del_rcu(&e->list);
978 list_del(&e->rule.list);
979 call_rcu(&e->rcu, audit_free_rule_rcu);
980
981 #ifdef CONFIG_AUDITSYSCALL
982 if (!dont_count)
983 audit_n_rules--;
984
985 if (!audit_match_signal(entry))
986 audit_signals--;
987 #endif
988 mutex_unlock(&audit_filter_mutex);
989
990 out:
991 if (watch)
992 audit_put_watch(watch); /* match initial get */
993 if (tree)
994 audit_put_tree(tree); /* that's the temporary one */
995
996 return ret;
997 }
998
999 /* List rules using struct audit_rule_data. */
1000 static void audit_list_rules(__u32 portid, int seq, struct sk_buff_head *q)
1001 {
1002 struct sk_buff *skb;
1003 struct audit_krule *r;
1004 int i;
1005
1006 /* This is a blocking read, so use audit_filter_mutex instead of rcu
1007 * iterator to sync with list writers. */
1008 for (i=0; i<AUDIT_NR_FILTERS; i++) {
1009 list_for_each_entry(r, &audit_rules_list[i], list) {
1010 struct audit_rule_data *data;
1011
1012 data = audit_krule_to_data(r);
1013 if (unlikely(!data))
1014 break;
1015 skb = audit_make_reply(portid, seq, AUDIT_LIST_RULES,
1016 0, 1, data,
1017 sizeof(*data) + data->buflen);
1018 if (skb)
1019 skb_queue_tail(q, skb);
1020 kfree(data);
1021 }
1022 }
1023 skb = audit_make_reply(portid, seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);
1024 if (skb)
1025 skb_queue_tail(q, skb);
1026 }
1027
1028 /* Log rule additions and removals */
1029 static void audit_log_rule_change(char *action, struct audit_krule *rule, int res)
1030 {
1031 struct audit_buffer *ab;
1032 uid_t loginuid = from_kuid(&init_user_ns, audit_get_loginuid(current));
1033 unsigned int sessionid = audit_get_sessionid(current);
1034
1035 if (!audit_enabled)
1036 return;
1037
1038 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
1039 if (!ab)
1040 return;
1041 audit_log_format(ab, "auid=%u ses=%u" ,loginuid, sessionid);
1042 audit_log_task_context(ab);
1043 audit_log_format(ab, " op=");
1044 audit_log_string(ab, action);
1045 audit_log_key(ab, rule->filterkey);
1046 audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
1047 audit_log_end(ab);
1048 }
1049
1050 /**
1051 * audit_rule_change - apply all rules to the specified message type
1052 * @type: audit message type
1053 * @portid: target port id for netlink audit messages
1054 * @seq: netlink audit message sequence (serial) number
1055 * @data: payload data
1056 * @datasz: size of payload data
1057 */
1058 int audit_rule_change(int type, __u32 portid, int seq, void *data,
1059 size_t datasz)
1060 {
1061 int err = 0;
1062 struct audit_entry *entry;
1063
1064 entry = audit_data_to_entry(data, datasz);
1065 if (IS_ERR(entry))
1066 return PTR_ERR(entry);
1067
1068 switch (type) {
1069 case AUDIT_ADD_RULE:
1070 err = audit_add_rule(entry);
1071 audit_log_rule_change("add_rule", &entry->rule, !err);
1072 break;
1073 case AUDIT_DEL_RULE:
1074 err = audit_del_rule(entry);
1075 audit_log_rule_change("remove_rule", &entry->rule, !err);
1076 break;
1077 default:
1078 err = -EINVAL;
1079 WARN_ON(1);
1080 }
1081
1082 if (err || type == AUDIT_DEL_RULE)
1083 audit_free_rule(entry);
1084
1085 return err;
1086 }
1087
1088 /**
1089 * audit_list_rules_send - list the audit rules
1090 * @request_skb: skb of request we are replying to (used to target the reply)
1091 * @seq: netlink audit message sequence (serial) number
1092 */
1093 int audit_list_rules_send(struct sk_buff *request_skb, int seq)
1094 {
1095 u32 portid = NETLINK_CB(request_skb).portid;
1096 struct net *net = sock_net(NETLINK_CB(request_skb).sk);
1097 struct task_struct *tsk;
1098 struct audit_netlink_list *dest;
1099 int err = 0;
1100
1101 /* We can't just spew out the rules here because we might fill
1102 * the available socket buffer space and deadlock waiting for
1103 * auditctl to read from it... which isn't ever going to
1104 * happen if we're actually running in the context of auditctl
1105 * trying to _send_ the stuff */
1106
1107 dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL);
1108 if (!dest)
1109 return -ENOMEM;
1110 dest->net = get_net(net);
1111 dest->portid = portid;
1112 skb_queue_head_init(&dest->q);
1113
1114 mutex_lock(&audit_filter_mutex);
1115 audit_list_rules(portid, seq, &dest->q);
1116 mutex_unlock(&audit_filter_mutex);
1117
1118 tsk = kthread_run(audit_send_list, dest, "audit_send_list");
1119 if (IS_ERR(tsk)) {
1120 skb_queue_purge(&dest->q);
1121 kfree(dest);
1122 err = PTR_ERR(tsk);
1123 }
1124
1125 return err;
1126 }
1127
1128 int audit_comparator(u32 left, u32 op, u32 right)
1129 {
1130 switch (op) {
1131 case Audit_equal:
1132 return (left == right);
1133 case Audit_not_equal:
1134 return (left != right);
1135 case Audit_lt:
1136 return (left < right);
1137 case Audit_le:
1138 return (left <= right);
1139 case Audit_gt:
1140 return (left > right);
1141 case Audit_ge:
1142 return (left >= right);
1143 case Audit_bitmask:
1144 return (left & right);
1145 case Audit_bittest:
1146 return ((left & right) == right);
1147 default:
1148 BUG();
1149 return 0;
1150 }
1151 }
1152
1153 int audit_uid_comparator(kuid_t left, u32 op, kuid_t right)
1154 {
1155 switch (op) {
1156 case Audit_equal:
1157 return uid_eq(left, right);
1158 case Audit_not_equal:
1159 return !uid_eq(left, right);
1160 case Audit_lt:
1161 return uid_lt(left, right);
1162 case Audit_le:
1163 return uid_lte(left, right);
1164 case Audit_gt:
1165 return uid_gt(left, right);
1166 case Audit_ge:
1167 return uid_gte(left, right);
1168 case Audit_bitmask:
1169 case Audit_bittest:
1170 default:
1171 BUG();
1172 return 0;
1173 }
1174 }
1175
1176 int audit_gid_comparator(kgid_t left, u32 op, kgid_t right)
1177 {
1178 switch (op) {
1179 case Audit_equal:
1180 return gid_eq(left, right);
1181 case Audit_not_equal:
1182 return !gid_eq(left, right);
1183 case Audit_lt:
1184 return gid_lt(left, right);
1185 case Audit_le:
1186 return gid_lte(left, right);
1187 case Audit_gt:
1188 return gid_gt(left, right);
1189 case Audit_ge:
1190 return gid_gte(left, right);
1191 case Audit_bitmask:
1192 case Audit_bittest:
1193 default:
1194 BUG();
1195 return 0;
1196 }
1197 }
1198
1199 /**
1200 * parent_len - find the length of the parent portion of a pathname
1201 * @path: pathname of which to determine length
1202 */
1203 int parent_len(const char *path)
1204 {
1205 int plen;
1206 const char *p;
1207
1208 plen = strlen(path);
1209
1210 if (plen == 0)
1211 return plen;
1212
1213 /* disregard trailing slashes */
1214 p = path + plen - 1;
1215 while ((*p == '/') && (p > path))
1216 p--;
1217
1218 /* walk backward until we find the next slash or hit beginning */
1219 while ((*p != '/') && (p > path))
1220 p--;
1221
1222 /* did we find a slash? Then increment to include it in path */
1223 if (*p == '/')
1224 p++;
1225
1226 return p - path;
1227 }
1228
1229 /**
1230 * audit_compare_dname_path - compare given dentry name with last component in
1231 * given path. Return of 0 indicates a match.
1232 * @dname: dentry name that we're comparing
1233 * @path: full pathname that we're comparing
1234 * @parentlen: length of the parent if known. Passing in AUDIT_NAME_FULL
1235 * here indicates that we must compute this value.
1236 */
1237 int audit_compare_dname_path(const char *dname, const char *path, int parentlen)
1238 {
1239 int dlen, pathlen;
1240 const char *p;
1241
1242 dlen = strlen(dname);
1243 pathlen = strlen(path);
1244 if (pathlen < dlen)
1245 return 1;
1246
1247 parentlen = parentlen == AUDIT_NAME_FULL ? parent_len(path) : parentlen;
1248 if (pathlen - parentlen != dlen)
1249 return 1;
1250
1251 p = path + parentlen;
1252
1253 return strncmp(p, dname, dlen);
1254 }
1255
1256 static int audit_filter_user_rules(struct audit_krule *rule, int type,
1257 enum audit_state *state)
1258 {
1259 int i;
1260
1261 for (i = 0; i < rule->field_count; i++) {
1262 struct audit_field *f = &rule->fields[i];
1263 pid_t pid;
1264 int result = 0;
1265 u32 sid;
1266
1267 switch (f->type) {
1268 case AUDIT_PID:
1269 pid = task_pid_nr(current);
1270 result = audit_comparator(pid, f->op, f->val);
1271 break;
1272 case AUDIT_UID:
1273 result = audit_uid_comparator(current_uid(), f->op, f->uid);
1274 break;
1275 case AUDIT_GID:
1276 result = audit_gid_comparator(current_gid(), f->op, f->gid);
1277 break;
1278 case AUDIT_LOGINUID:
1279 result = audit_uid_comparator(audit_get_loginuid(current),
1280 f->op, f->uid);
1281 break;
1282 case AUDIT_LOGINUID_SET:
1283 result = audit_comparator(audit_loginuid_set(current),
1284 f->op, f->val);
1285 break;
1286 case AUDIT_MSGTYPE:
1287 result = audit_comparator(type, f->op, f->val);
1288 break;
1289 case AUDIT_SUBJ_USER:
1290 case AUDIT_SUBJ_ROLE:
1291 case AUDIT_SUBJ_TYPE:
1292 case AUDIT_SUBJ_SEN:
1293 case AUDIT_SUBJ_CLR:
1294 if (f->lsm_rule) {
1295 security_task_getsecid(current, &sid);
1296 result = security_audit_rule_match(sid,
1297 f->type,
1298 f->op,
1299 f->lsm_rule,
1300 NULL);
1301 }
1302 break;
1303 }
1304
1305 if (!result)
1306 return 0;
1307 }
1308 switch (rule->action) {
1309 case AUDIT_NEVER: *state = AUDIT_DISABLED; break;
1310 case AUDIT_ALWAYS: *state = AUDIT_RECORD_CONTEXT; break;
1311 }
1312 return 1;
1313 }
1314
1315 int audit_filter_user(int type)
1316 {
1317 enum audit_state state = AUDIT_DISABLED;
1318 struct audit_entry *e;
1319 int rc, ret;
1320
1321 ret = 1; /* Audit by default */
1322
1323 rcu_read_lock();
1324 list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_USER], list) {
1325 rc = audit_filter_user_rules(&e->rule, type, &state);
1326 if (rc) {
1327 if (rc > 0 && state == AUDIT_DISABLED)
1328 ret = 0;
1329 break;
1330 }
1331 }
1332 rcu_read_unlock();
1333
1334 return ret;
1335 }
1336
1337 int audit_filter_type(int type)
1338 {
1339 struct audit_entry *e;
1340 int result = 0;
1341
1342 rcu_read_lock();
1343 if (list_empty(&audit_filter_list[AUDIT_FILTER_TYPE]))
1344 goto unlock_and_return;
1345
1346 list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_TYPE],
1347 list) {
1348 int i;
1349 for (i = 0; i < e->rule.field_count; i++) {
1350 struct audit_field *f = &e->rule.fields[i];
1351 if (f->type == AUDIT_MSGTYPE) {
1352 result = audit_comparator(type, f->op, f->val);
1353 if (!result)
1354 break;
1355 }
1356 }
1357 if (result)
1358 goto unlock_and_return;
1359 }
1360 unlock_and_return:
1361 rcu_read_unlock();
1362 return result;
1363 }
1364
1365 static int update_lsm_rule(struct audit_krule *r)
1366 {
1367 struct audit_entry *entry = container_of(r, struct audit_entry, rule);
1368 struct audit_entry *nentry;
1369 int err = 0;
1370
1371 if (!security_audit_rule_known(r))
1372 return 0;
1373
1374 nentry = audit_dupe_rule(r);
1375 if (IS_ERR(nentry)) {
1376 /* save the first error encountered for the
1377 * return value */
1378 err = PTR_ERR(nentry);
1379 audit_panic("error updating LSM filters");
1380 if (r->watch)
1381 list_del(&r->rlist);
1382 list_del_rcu(&entry->list);
1383 list_del(&r->list);
1384 } else {
1385 if (r->watch || r->tree)
1386 list_replace_init(&r->rlist, &nentry->rule.rlist);
1387 list_replace_rcu(&entry->list, &nentry->list);
1388 list_replace(&r->list, &nentry->rule.list);
1389 }
1390 call_rcu(&entry->rcu, audit_free_rule_rcu);
1391
1392 return err;
1393 }
1394
1395 /* This function will re-initialize the lsm_rule field of all applicable rules.
1396 * It will traverse the filter lists serarching for rules that contain LSM
1397 * specific filter fields. When such a rule is found, it is copied, the
1398 * LSM field is re-initialized, and the old rule is replaced with the
1399 * updated rule. */
1400 int audit_update_lsm_rules(void)
1401 {
1402 struct audit_krule *r, *n;
1403 int i, err = 0;
1404
1405 /* audit_filter_mutex synchronizes the writers */
1406 mutex_lock(&audit_filter_mutex);
1407
1408 for (i = 0; i < AUDIT_NR_FILTERS; i++) {
1409 list_for_each_entry_safe(r, n, &audit_rules_list[i], list) {
1410 int res = update_lsm_rule(r);
1411 if (!err)
1412 err = res;
1413 }
1414 }
1415 mutex_unlock(&audit_filter_mutex);
1416
1417 return err;
1418 }
Linux kernel - Deliverables
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