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Linux 3.16.75
[linux/fpc-iii.git] / kernel / auditfilter.c
blob58200abb8d63adb1321821599bf9878c6f37dfbc
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 inline void audit_free_rule(struct audit_entry *e)
75 {
76 int i;
77 struct audit_krule *erule = &e->rule;
78
79 /* some rules don't have associated watches */
80 if (erule->watch)
81 audit_put_watch(erule->watch);
82 if (erule->fields)
83 for (i = 0; i < erule->field_count; i++) {
84 struct audit_field *f = &erule->fields[i];
85 kfree(f->lsm_str);
86 security_audit_rule_free(f->lsm_rule);
87 }
88 kfree(erule->fields);
89 kfree(erule->filterkey);
90 kfree(e);
91 }
92
93 void audit_free_rule_rcu(struct rcu_head *head)
94 {
95 struct audit_entry *e = container_of(head, struct audit_entry, rcu);
96 audit_free_rule(e);
97 }
98
99 /* Initialize an audit filterlist entry. */
100 static inline struct audit_entry *audit_init_entry(u32 field_count)
101 {
102 struct audit_entry *entry;
103 struct audit_field *fields;
104
105 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
106 if (unlikely(!entry))
107 return NULL;
108
109 fields = kzalloc(sizeof(*fields) * field_count, GFP_KERNEL);
110 if (unlikely(!fields)) {
111 kfree(entry);
112 return NULL;
113 }
114 entry->rule.fields = fields;
115
116 return entry;
117 }
118
119 /* Unpack a filter field's string representation from user-space
120 * buffer. */
121 char *audit_unpack_string(void **bufp, size_t *remain, size_t len)
122 {
123 char *str;
124
125 if (!*bufp || (len == 0) || (len > *remain))
126 return ERR_PTR(-EINVAL);
127
128 /* Of the currently implemented string fields, PATH_MAX
129 * defines the longest valid length.
130 */
131 if (len > PATH_MAX)
132 return ERR_PTR(-ENAMETOOLONG);
133
134 str = kmalloc(len + 1, GFP_KERNEL);
135 if (unlikely(!str))
136 return ERR_PTR(-ENOMEM);
137
138 memcpy(str, *bufp, len);
139 str[len] = 0;
140 *bufp += len;
141 *remain -= len;
142
143 return str;
144 }
145
146 /* Translate an inode field to kernel respresentation. */
147 static inline int audit_to_inode(struct audit_krule *krule,
148 struct audit_field *f)
149 {
150 if (krule->listnr != AUDIT_FILTER_EXIT ||
151 krule->watch || krule->inode_f || krule->tree ||
152 (f->op != Audit_equal && f->op != Audit_not_equal))
153 return -EINVAL;
154
155 krule->inode_f = f;
156 return 0;
157 }
158
159 static __u32 *classes[AUDIT_SYSCALL_CLASSES];
160
161 int __init audit_register_class(int class, unsigned *list)
162 {
163 __u32 *p = kzalloc(AUDIT_BITMASK_SIZE * sizeof(__u32), GFP_KERNEL);
164 if (!p)
165 return -ENOMEM;
166 while (*list != ~0U) {
167 unsigned n = *list++;
168 if (n >= AUDIT_BITMASK_SIZE * 32 - AUDIT_SYSCALL_CLASSES) {
169 kfree(p);
170 return -EINVAL;
171 }
172 p[AUDIT_WORD(n)] |= AUDIT_BIT(n);
173 }
174 if (class >= AUDIT_SYSCALL_CLASSES || classes[class]) {
175 kfree(p);
176 return -EINVAL;
177 }
178 classes[class] = p;
179 return 0;
180 }
181
182 int audit_match_class(int class, unsigned syscall)
183 {
184 if (unlikely(syscall >= AUDIT_BITMASK_SIZE * 32))
185 return 0;
186 if (unlikely(class >= AUDIT_SYSCALL_CLASSES || !classes[class]))
187 return 0;
188 return classes[class][AUDIT_WORD(syscall)] & AUDIT_BIT(syscall);
189 }
190
191 #ifdef CONFIG_AUDITSYSCALL
192 static inline int audit_match_class_bits(int class, u32 *mask)
193 {
194 int i;
195
196 if (classes[class]) {
197 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
198 if (mask[i] & classes[class][i])
199 return 0;
200 }
201 return 1;
202 }
203
204 static int audit_match_signal(struct audit_entry *entry)
205 {
206 struct audit_field *arch = entry->rule.arch_f;
207
208 if (!arch) {
209 /* When arch is unspecified, we must check both masks on biarch
210 * as syscall number alone is ambiguous. */
211 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
212 entry->rule.mask) &&
213 audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
214 entry->rule.mask));
215 }
216
217 switch(audit_classify_arch(arch->val)) {
218 case 0: /* native */
219 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
220 entry->rule.mask));
221 case 1: /* 32bit on biarch */
222 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
223 entry->rule.mask));
224 default:
225 return 1;
226 }
227 }
228 #endif
229
230 /* Common user-space to kernel rule translation. */
231 static inline struct audit_entry *audit_to_entry_common(struct audit_rule_data *rule)
232 {
233 unsigned listnr;
234 struct audit_entry *entry;
235 int i, err;
236
237 err = -EINVAL;
238 listnr = rule->flags & ~AUDIT_FILTER_PREPEND;
239 switch(listnr) {
240 default:
241 goto exit_err;
242 #ifdef CONFIG_AUDITSYSCALL
243 case AUDIT_FILTER_ENTRY:
244 if (rule->action == AUDIT_ALWAYS)
245 goto exit_err;
246 case AUDIT_FILTER_EXIT:
247 case AUDIT_FILTER_TASK:
248 #endif
249 case AUDIT_FILTER_USER:
250 case AUDIT_FILTER_TYPE:
251 ;
252 }
253 if (unlikely(rule->action == AUDIT_POSSIBLE)) {
254 pr_err("AUDIT_POSSIBLE is deprecated\n");
255 goto exit_err;
256 }
257 if (rule->action != AUDIT_NEVER && rule->action != AUDIT_ALWAYS)
258 goto exit_err;
259 if (rule->field_count > AUDIT_MAX_FIELDS)
260 goto exit_err;
261
262 err = -ENOMEM;
263 entry = audit_init_entry(rule->field_count);
264 if (!entry)
265 goto exit_err;
266
267 entry->rule.flags = rule->flags & AUDIT_FILTER_PREPEND;
268 entry->rule.listnr = listnr;
269 entry->rule.action = rule->action;
270 entry->rule.field_count = rule->field_count;
271
272 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
273 entry->rule.mask[i] = rule->mask[i];
274
275 for (i = 0; i < AUDIT_SYSCALL_CLASSES; i++) {
276 int bit = AUDIT_BITMASK_SIZE * 32 - i - 1;
277 __u32 *p = &entry->rule.mask[AUDIT_WORD(bit)];
278 __u32 *class;
279
280 if (!(*p & AUDIT_BIT(bit)))
281 continue;
282 *p &= ~AUDIT_BIT(bit);
283 class = classes[i];
284 if (class) {
285 int j;
286 for (j = 0; j < AUDIT_BITMASK_SIZE; j++)
287 entry->rule.mask[j] |= class[j];
288 }
289 }
290
291 return entry;
292
293 exit_err:
294 return ERR_PTR(err);
295 }
296
297 static u32 audit_ops[] =
298 {
299 [Audit_equal] = AUDIT_EQUAL,
300 [Audit_not_equal] = AUDIT_NOT_EQUAL,
301 [Audit_bitmask] = AUDIT_BIT_MASK,
302 [Audit_bittest] = AUDIT_BIT_TEST,
303 [Audit_lt] = AUDIT_LESS_THAN,
304 [Audit_gt] = AUDIT_GREATER_THAN,
305 [Audit_le] = AUDIT_LESS_THAN_OR_EQUAL,
306 [Audit_ge] = AUDIT_GREATER_THAN_OR_EQUAL,
307 };
308
309 static u32 audit_to_op(u32 op)
310 {
311 u32 n;
312 for (n = Audit_equal; n < Audit_bad && audit_ops[n] != op; n++)
313 ;
314 return n;
315 }
316
317 /* check if an audit field is valid */
318 static int audit_field_valid(struct audit_entry *entry, struct audit_field *f)
319 {
320 switch(f->type) {
321 case AUDIT_MSGTYPE:
322 if (entry->rule.listnr != AUDIT_FILTER_TYPE &&
323 entry->rule.listnr != AUDIT_FILTER_USER)
324 return -EINVAL;
325 break;
326 };
327
328 switch(f->type) {
329 default:
330 return -EINVAL;
331 case AUDIT_UID:
332 case AUDIT_EUID:
333 case AUDIT_SUID:
334 case AUDIT_FSUID:
335 case AUDIT_LOGINUID:
336 case AUDIT_OBJ_UID:
337 case AUDIT_GID:
338 case AUDIT_EGID:
339 case AUDIT_SGID:
340 case AUDIT_FSGID:
341 case AUDIT_OBJ_GID:
342 case AUDIT_PID:
343 case AUDIT_PERS:
344 case AUDIT_MSGTYPE:
345 case AUDIT_PPID:
346 case AUDIT_DEVMAJOR:
347 case AUDIT_DEVMINOR:
348 case AUDIT_EXIT:
349 case AUDIT_SUCCESS:
350 case AUDIT_INODE:
351 /* bit ops are only useful on syscall args */
352 if (f->op == Audit_bitmask || f->op == Audit_bittest)
353 return -EINVAL;
354 break;
355 case AUDIT_ARG0:
356 case AUDIT_ARG1:
357 case AUDIT_ARG2:
358 case AUDIT_ARG3:
359 case AUDIT_SUBJ_USER:
360 case AUDIT_SUBJ_ROLE:
361 case AUDIT_SUBJ_TYPE:
362 case AUDIT_SUBJ_SEN:
363 case AUDIT_SUBJ_CLR:
364 case AUDIT_OBJ_USER:
365 case AUDIT_OBJ_ROLE:
366 case AUDIT_OBJ_TYPE:
367 case AUDIT_OBJ_LEV_LOW:
368 case AUDIT_OBJ_LEV_HIGH:
369 case AUDIT_WATCH:
370 case AUDIT_DIR:
371 case AUDIT_FILTERKEY:
372 break;
373 case AUDIT_LOGINUID_SET:
374 if ((f->val != 0) && (f->val != 1))
375 return -EINVAL;
376 /* FALL THROUGH */
377 case AUDIT_ARCH:
378 if (f->op != Audit_not_equal && f->op != Audit_equal)
379 return -EINVAL;
380 break;
381 case AUDIT_PERM:
382 if (f->val & ~15)
383 return -EINVAL;
384 break;
385 case AUDIT_FILETYPE:
386 if (f->val & ~S_IFMT)
387 return -EINVAL;
388 break;
389 case AUDIT_FIELD_COMPARE:
390 if (f->val > AUDIT_MAX_FIELD_COMPARE)
391 return -EINVAL;
392 break;
393 };
394 return 0;
395 }
396
397 /* Translate struct audit_rule_data to kernel's rule respresentation. */
398 static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
399 size_t datasz)
400 {
401 int err = 0;
402 struct audit_entry *entry;
403 void *bufp;
404 size_t remain = datasz - sizeof(struct audit_rule_data);
405 int i;
406 char *str;
407
408 entry = audit_to_entry_common(data);
409 if (IS_ERR(entry))
410 goto exit_nofree;
411
412 bufp = data->buf;
413 entry->rule.vers_ops = 2;
414 for (i = 0; i < data->field_count; i++) {
415 struct audit_field *f = &entry->rule.fields[i];
416
417 err = -EINVAL;
418
419 f->op = audit_to_op(data->fieldflags[i]);
420 if (f->op == Audit_bad)
421 goto exit_free;
422
423 f->type = data->fields[i];
424 f->val = data->values[i];
425 f->uid = INVALID_UID;
426 f->gid = INVALID_GID;
427 f->lsm_str = NULL;
428 f->lsm_rule = NULL;
429
430 /* Support legacy tests for a valid loginuid */
431 if ((f->type == AUDIT_LOGINUID) && (f->val == AUDIT_UID_UNSET)) {
432 f->type = AUDIT_LOGINUID_SET;
433 f->val = 0;
434 entry->rule.pflags |= AUDIT_LOGINUID_LEGACY;
435 }
436
437 err = audit_field_valid(entry, f);
438 if (err)
439 goto exit_free;
440
441 err = -EINVAL;
442 switch (f->type) {
443 case AUDIT_LOGINUID:
444 case AUDIT_UID:
445 case AUDIT_EUID:
446 case AUDIT_SUID:
447 case AUDIT_FSUID:
448 case AUDIT_OBJ_UID:
449 f->uid = make_kuid(current_user_ns(), f->val);
450 if (!uid_valid(f->uid))
451 goto exit_free;
452 break;
453 case AUDIT_GID:
454 case AUDIT_EGID:
455 case AUDIT_SGID:
456 case AUDIT_FSGID:
457 case AUDIT_OBJ_GID:
458 f->gid = make_kgid(current_user_ns(), f->val);
459 if (!gid_valid(f->gid))
460 goto exit_free;
461 break;
462 case AUDIT_ARCH:
463 entry->rule.arch_f = f;
464 break;
465 case AUDIT_SUBJ_USER:
466 case AUDIT_SUBJ_ROLE:
467 case AUDIT_SUBJ_TYPE:
468 case AUDIT_SUBJ_SEN:
469 case AUDIT_SUBJ_CLR:
470 case AUDIT_OBJ_USER:
471 case AUDIT_OBJ_ROLE:
472 case AUDIT_OBJ_TYPE:
473 case AUDIT_OBJ_LEV_LOW:
474 case AUDIT_OBJ_LEV_HIGH:
475 str = audit_unpack_string(&bufp, &remain, f->val);
476 if (IS_ERR(str))
477 goto exit_free;
478 entry->rule.buflen += f->val;
479
480 err = security_audit_rule_init(f->type, f->op, str,
481 (void **)&f->lsm_rule);
482 /* Keep currently invalid fields around in case they
483 * become valid after a policy reload. */
484 if (err == -EINVAL) {
485 pr_warn("audit rule for LSM \'%s\' is invalid\n",
486 str);
487 err = 0;
488 }
489 if (err) {
490 kfree(str);
491 goto exit_free;
492 } else
493 f->lsm_str = str;
494 break;
495 case AUDIT_WATCH:
496 str = audit_unpack_string(&bufp, &remain, f->val);
497 if (IS_ERR(str))
498 goto exit_free;
499 entry->rule.buflen += f->val;
500
501 err = audit_to_watch(&entry->rule, str, f->val, f->op);
502 if (err) {
503 kfree(str);
504 goto exit_free;
505 }
506 break;
507 case AUDIT_DIR:
508 str = audit_unpack_string(&bufp, &remain, f->val);
509 if (IS_ERR(str))
510 goto exit_free;
511 entry->rule.buflen += f->val;
512
513 err = audit_make_tree(&entry->rule, str, f->op);
514 kfree(str);
515 if (err)
516 goto exit_free;
517 break;
518 case AUDIT_INODE:
519 err = audit_to_inode(&entry->rule, f);
520 if (err)
521 goto exit_free;
522 break;
523 case AUDIT_FILTERKEY:
524 if (entry->rule.filterkey || f->val > AUDIT_MAX_KEY_LEN)
525 goto exit_free;
526 str = audit_unpack_string(&bufp, &remain, f->val);
527 if (IS_ERR(str))
528 goto exit_free;
529 entry->rule.buflen += f->val;
530 entry->rule.filterkey = str;
531 break;
532 }
533 }
534
535 if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal)
536 entry->rule.inode_f = NULL;
537
538 exit_nofree:
539 return entry;
540
541 exit_free:
542 if (entry->rule.watch)
543 audit_put_watch(entry->rule.watch); /* matches initial get */
544 if (entry->rule.tree)
545 audit_put_tree(entry->rule.tree); /* that's the temporary one */
546 audit_free_rule(entry);
547 return ERR_PTR(err);
548 }
549
550 /* Pack a filter field's string representation into data block. */
551 static inline size_t audit_pack_string(void **bufp, const char *str)
552 {
553 size_t len = strlen(str);
554
555 memcpy(*bufp, str, len);
556 *bufp += len;
557
558 return len;
559 }
560
561 /* Translate kernel rule respresentation to struct audit_rule_data. */
562 static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule)
563 {
564 struct audit_rule_data *data;
565 void *bufp;
566 int i;
567
568 data = kmalloc(sizeof(*data) + krule->buflen, GFP_KERNEL);
569 if (unlikely(!data))
570 return NULL;
571 memset(data, 0, sizeof(*data));
572
573 data->flags = krule->flags | krule->listnr;
574 data->action = krule->action;
575 data->field_count = krule->field_count;
576 bufp = data->buf;
577 for (i = 0; i < data->field_count; i++) {
578 struct audit_field *f = &krule->fields[i];
579
580 data->fields[i] = f->type;
581 data->fieldflags[i] = audit_ops[f->op];
582 switch(f->type) {
583 case AUDIT_SUBJ_USER:
584 case AUDIT_SUBJ_ROLE:
585 case AUDIT_SUBJ_TYPE:
586 case AUDIT_SUBJ_SEN:
587 case AUDIT_SUBJ_CLR:
588 case AUDIT_OBJ_USER:
589 case AUDIT_OBJ_ROLE:
590 case AUDIT_OBJ_TYPE:
591 case AUDIT_OBJ_LEV_LOW:
592 case AUDIT_OBJ_LEV_HIGH:
593 data->buflen += data->values[i] =
594 audit_pack_string(&bufp, f->lsm_str);
595 break;
596 case AUDIT_WATCH:
597 data->buflen += data->values[i] =
598 audit_pack_string(&bufp,
599 audit_watch_path(krule->watch));
600 break;
601 case AUDIT_DIR:
602 data->buflen += data->values[i] =
603 audit_pack_string(&bufp,
604 audit_tree_path(krule->tree));
605 break;
606 case AUDIT_FILTERKEY:
607 data->buflen += data->values[i] =
608 audit_pack_string(&bufp, krule->filterkey);
609 break;
610 case AUDIT_LOGINUID_SET:
611 if (krule->pflags & AUDIT_LOGINUID_LEGACY && !f->val) {
612 data->fields[i] = AUDIT_LOGINUID;
613 data->values[i] = AUDIT_UID_UNSET;
614 break;
615 }
616 /* fallthrough if set */
617 default:
618 data->values[i] = f->val;
619 }
620 }
621 for (i = 0; i < AUDIT_BITMASK_SIZE; i++) data->mask[i] = krule->mask[i];
622
623 return data;
624 }
625
626 /* Compare two rules in kernel format. Considered success if rules
627 * don't match. */
628 static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
629 {
630 int i;
631
632 if (a->flags != b->flags ||
633 a->pflags != b->pflags ||
634 a->listnr != b->listnr ||
635 a->action != b->action ||
636 a->field_count != b->field_count)
637 return 1;
638
639 for (i = 0; i < a->field_count; i++) {
640 if (a->fields[i].type != b->fields[i].type ||
641 a->fields[i].op != b->fields[i].op)
642 return 1;
643
644 switch(a->fields[i].type) {
645 case AUDIT_SUBJ_USER:
646 case AUDIT_SUBJ_ROLE:
647 case AUDIT_SUBJ_TYPE:
648 case AUDIT_SUBJ_SEN:
649 case AUDIT_SUBJ_CLR:
650 case AUDIT_OBJ_USER:
651 case AUDIT_OBJ_ROLE:
652 case AUDIT_OBJ_TYPE:
653 case AUDIT_OBJ_LEV_LOW:
654 case AUDIT_OBJ_LEV_HIGH:
655 if (strcmp(a->fields[i].lsm_str, b->fields[i].lsm_str))
656 return 1;
657 break;
658 case AUDIT_WATCH:
659 if (strcmp(audit_watch_path(a->watch),
660 audit_watch_path(b->watch)))
661 return 1;
662 break;
663 case AUDIT_DIR:
664 if (strcmp(audit_tree_path(a->tree),
665 audit_tree_path(b->tree)))
666 return 1;
667 break;
668 case AUDIT_FILTERKEY:
669 /* both filterkeys exist based on above type compare */
670 if (strcmp(a->filterkey, b->filterkey))
671 return 1;
672 break;
673 case AUDIT_UID:
674 case AUDIT_EUID:
675 case AUDIT_SUID:
676 case AUDIT_FSUID:
677 case AUDIT_LOGINUID:
678 case AUDIT_OBJ_UID:
679 if (!uid_eq(a->fields[i].uid, b->fields[i].uid))
680 return 1;
681 break;
682 case AUDIT_GID:
683 case AUDIT_EGID:
684 case AUDIT_SGID:
685 case AUDIT_FSGID:
686 case AUDIT_OBJ_GID:
687 if (!gid_eq(a->fields[i].gid, b->fields[i].gid))
688 return 1;
689 break;
690 default:
691 if (a->fields[i].val != b->fields[i].val)
692 return 1;
693 }
694 }
695
696 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
697 if (a->mask[i] != b->mask[i])
698 return 1;
699
700 return 0;
701 }
702
703 /* Duplicate LSM field information. The lsm_rule is opaque, so must be
704 * re-initialized. */
705 static inline int audit_dupe_lsm_field(struct audit_field *df,
706 struct audit_field *sf)
707 {
708 int ret = 0;
709 char *lsm_str;
710
711 /* our own copy of lsm_str */
712 lsm_str = kstrdup(sf->lsm_str, GFP_KERNEL);
713 if (unlikely(!lsm_str))
714 return -ENOMEM;
715 df->lsm_str = lsm_str;
716
717 /* our own (refreshed) copy of lsm_rule */
718 ret = security_audit_rule_init(df->type, df->op, df->lsm_str,
719 (void **)&df->lsm_rule);
720 /* Keep currently invalid fields around in case they
721 * become valid after a policy reload. */
722 if (ret == -EINVAL) {
723 pr_warn("audit rule for LSM \'%s\' is invalid\n",
724 df->lsm_str);
725 ret = 0;
726 }
727
728 return ret;
729 }
730
731 /* Duplicate an audit rule. This will be a deep copy with the exception
732 * of the watch - that pointer is carried over. The LSM specific fields
733 * will be updated in the copy. The point is to be able to replace the old
734 * rule with the new rule in the filterlist, then free the old rule.
735 * The rlist element is undefined; list manipulations are handled apart from
736 * the initial copy. */
737 struct audit_entry *audit_dupe_rule(struct audit_krule *old)
738 {
739 u32 fcount = old->field_count;
740 struct audit_entry *entry;
741 struct audit_krule *new;
742 char *fk;
743 int i, err = 0;
744
745 entry = audit_init_entry(fcount);
746 if (unlikely(!entry))
747 return ERR_PTR(-ENOMEM);
748
749 new = &entry->rule;
750 new->vers_ops = old->vers_ops;
751 new->flags = old->flags;
752 new->pflags = old->pflags;
753 new->listnr = old->listnr;
754 new->action = old->action;
755 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
756 new->mask[i] = old->mask[i];
757 new->prio = old->prio;
758 new->buflen = old->buflen;
759 new->inode_f = old->inode_f;
760 new->field_count = old->field_count;
761
762 /*
763 * note that we are OK with not refcounting here; audit_match_tree()
764 * never dereferences tree and we can't get false positives there
765 * since we'd have to have rule gone from the list *and* removed
766 * before the chunks found by lookup had been allocated, i.e. before
767 * the beginning of list scan.
768 */
769 new->tree = old->tree;
770 memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount);
771
772 /* deep copy this information, updating the lsm_rule fields, because
773 * the originals will all be freed when the old rule is freed. */
774 for (i = 0; i < fcount; i++) {
775 switch (new->fields[i].type) {
776 case AUDIT_SUBJ_USER:
777 case AUDIT_SUBJ_ROLE:
778 case AUDIT_SUBJ_TYPE:
779 case AUDIT_SUBJ_SEN:
780 case AUDIT_SUBJ_CLR:
781 case AUDIT_OBJ_USER:
782 case AUDIT_OBJ_ROLE:
783 case AUDIT_OBJ_TYPE:
784 case AUDIT_OBJ_LEV_LOW:
785 case AUDIT_OBJ_LEV_HIGH:
786 err = audit_dupe_lsm_field(&new->fields[i],
787 &old->fields[i]);
788 break;
789 case AUDIT_FILTERKEY:
790 fk = kstrdup(old->filterkey, GFP_KERNEL);
791 if (unlikely(!fk))
792 err = -ENOMEM;
793 else
794 new->filterkey = fk;
795 }
796 if (err) {
797 audit_free_rule(entry);
798 return ERR_PTR(err);
799 }
800 }
801
802 if (old->watch) {
803 audit_get_watch(old->watch);
804 new->watch = old->watch;
805 }
806
807 return entry;
808 }
809
810 /* Find an existing audit rule.
811 * Caller must hold audit_filter_mutex to prevent stale rule data. */
812 static struct audit_entry *audit_find_rule(struct audit_entry *entry,
813 struct list_head **p)
814 {
815 struct audit_entry *e, *found = NULL;
816 struct list_head *list;
817 int h;
818
819 if (entry->rule.inode_f) {
820 h = audit_hash_ino(entry->rule.inode_f->val);
821 *p = list = &audit_inode_hash[h];
822 } else if (entry->rule.watch) {
823 /* we don't know the inode number, so must walk entire hash */
824 for (h = 0; h < AUDIT_INODE_BUCKETS; h++) {
825 list = &audit_inode_hash[h];
826 list_for_each_entry(e, list, list)
827 if (!audit_compare_rule(&entry->rule, &e->rule)) {
828 found = e;
829 goto out;
830 }
831 }
832 goto out;
833 } else {
834 *p = list = &audit_filter_list[entry->rule.listnr];
835 }
836
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 out:
844 return found;
845 }
846
847 static u64 prio_low = ~0ULL/2;
848 static u64 prio_high = ~0ULL/2 - 1;
849
850 /* Add rule to given filterlist if not a duplicate. */
851 static inline int audit_add_rule(struct audit_entry *entry)
852 {
853 struct audit_entry *e;
854 struct audit_watch *watch = entry->rule.watch;
855 struct audit_tree *tree = entry->rule.tree;
856 struct list_head *list;
857 int err;
858 #ifdef CONFIG_AUDITSYSCALL
859 int dont_count = 0;
860
861 /* If either of these, don't count towards total */
862 if (entry->rule.listnr == AUDIT_FILTER_USER ||
863 entry->rule.listnr == AUDIT_FILTER_TYPE)
864 dont_count = 1;
865 #endif
866
867 mutex_lock(&audit_filter_mutex);
868 e = audit_find_rule(entry, &list);
869 if (e) {
870 mutex_unlock(&audit_filter_mutex);
871 err = -EEXIST;
872 /* normally audit_add_tree_rule() will free it on failure */
873 if (tree)
874 audit_put_tree(tree);
875 goto error;
876 }
877
878 if (watch) {
879 /* audit_filter_mutex is dropped and re-taken during this call */
880 err = audit_add_watch(&entry->rule, &list);
881 if (err) {
882 mutex_unlock(&audit_filter_mutex);
883 /*
884 * normally audit_add_tree_rule() will free it
885 * on failure
886 */
887 if (tree)
888 audit_put_tree(tree);
889 goto error;
890 }
891 }
892 if (tree) {
893 err = audit_add_tree_rule(&entry->rule);
894 if (err) {
895 mutex_unlock(&audit_filter_mutex);
896 goto error;
897 }
898 }
899
900 entry->rule.prio = ~0ULL;
901 if (entry->rule.listnr == AUDIT_FILTER_EXIT) {
902 if (entry->rule.flags & AUDIT_FILTER_PREPEND)
903 entry->rule.prio = ++prio_high;
904 else
905 entry->rule.prio = --prio_low;
906 }
907
908 if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
909 list_add(&entry->rule.list,
910 &audit_rules_list[entry->rule.listnr]);
911 list_add_rcu(&entry->list, list);
912 entry->rule.flags &= ~AUDIT_FILTER_PREPEND;
913 } else {
914 list_add_tail(&entry->rule.list,
915 &audit_rules_list[entry->rule.listnr]);
916 list_add_tail_rcu(&entry->list, list);
917 }
918 #ifdef CONFIG_AUDITSYSCALL
919 if (!dont_count)
920 audit_n_rules++;
921
922 if (!audit_match_signal(entry))
923 audit_signals++;
924 #endif
925 mutex_unlock(&audit_filter_mutex);
926
927 return 0;
928
929 error:
930 if (watch)
931 audit_put_watch(watch); /* tmp watch, matches initial get */
932 return err;
933 }
934
935 /* Remove an existing rule from filterlist. */
936 static inline int audit_del_rule(struct audit_entry *entry)
937 {
938 struct audit_entry *e;
939 struct audit_watch *watch = entry->rule.watch;
940 struct audit_tree *tree = entry->rule.tree;
941 struct list_head *list;
942 int ret = 0;
943 #ifdef CONFIG_AUDITSYSCALL
944 int dont_count = 0;
945
946 /* If either of these, don't count towards total */
947 if (entry->rule.listnr == AUDIT_FILTER_USER ||
948 entry->rule.listnr == AUDIT_FILTER_TYPE)
949 dont_count = 1;
950 #endif
951
952 mutex_lock(&audit_filter_mutex);
953 e = audit_find_rule(entry, &list);
954 if (!e) {
955 mutex_unlock(&audit_filter_mutex);
956 ret = -ENOENT;
957 goto out;
958 }
959
960 if (e->rule.watch)
961 audit_remove_watch_rule(&e->rule);
962
963 if (e->rule.tree)
964 audit_remove_tree_rule(&e->rule);
965
966 list_del_rcu(&e->list);
967 list_del(&e->rule.list);
968 call_rcu(&e->rcu, audit_free_rule_rcu);
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 out:
980 if (watch)
981 audit_put_watch(watch); /* match initial get */
982 if (tree)
983 audit_put_tree(tree); /* that's the temporary one */
984
985 return ret;
986 }
987
988 /* List rules using struct audit_rule_data. */
989 static void audit_list_rules(__u32 portid, int seq, struct sk_buff_head *q)
990 {
991 struct sk_buff *skb;
992 struct audit_krule *r;
993 int i;
994
995 /* This is a blocking read, so use audit_filter_mutex instead of rcu
996 * iterator to sync with list writers. */
997 for (i=0; i<AUDIT_NR_FILTERS; i++) {
998 list_for_each_entry(r, &audit_rules_list[i], list) {
999 struct audit_rule_data *data;
1000
1001 data = audit_krule_to_data(r);
1002 if (unlikely(!data))
1003 break;
1004 skb = audit_make_reply(portid, seq, AUDIT_LIST_RULES,
1005 0, 1, data,
1006 sizeof(*data) + data->buflen);
1007 if (skb)
1008 skb_queue_tail(q, skb);
1009 kfree(data);
1010 }
1011 }
1012 skb = audit_make_reply(portid, seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);
1013 if (skb)
1014 skb_queue_tail(q, skb);
1015 }
1016
1017 /* Log rule additions and removals */
1018 static void audit_log_rule_change(char *action, struct audit_krule *rule, int res)
1019 {
1020 struct audit_buffer *ab;
1021 uid_t loginuid = from_kuid(&init_user_ns, audit_get_loginuid(current));
1022 unsigned int sessionid = audit_get_sessionid(current);
1023
1024 if (!audit_enabled)
1025 return;
1026
1027 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
1028 if (!ab)
1029 return;
1030 audit_log_format(ab, "auid=%u ses=%u" ,loginuid, sessionid);
1031 audit_log_task_context(ab);
1032 audit_log_format(ab, " op=");
1033 audit_log_string(ab, action);
1034 audit_log_key(ab, rule->filterkey);
1035 audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
1036 audit_log_end(ab);
1037 }
1038
1039 /**
1040 * audit_rule_change - apply all rules to the specified message type
1041 * @type: audit message type
1042 * @portid: target port id for netlink audit messages
1043 * @seq: netlink audit message sequence (serial) number
1044 * @data: payload data
1045 * @datasz: size of payload data
1046 */
1047 int audit_rule_change(int type, __u32 portid, int seq, void *data,
1048 size_t datasz)
1049 {
1050 int err = 0;
1051 struct audit_entry *entry;
1052
1053 switch (type) {
1054 case AUDIT_ADD_RULE:
1055 entry = audit_data_to_entry(data, datasz);
1056 if (IS_ERR(entry))
1057 return PTR_ERR(entry);
1058
1059 err = audit_add_rule(entry);
1060 audit_log_rule_change("add rule", &entry->rule, !err);
1061 if (err)
1062 audit_free_rule(entry);
1063 break;
1064 case AUDIT_DEL_RULE:
1065 entry = audit_data_to_entry(data, datasz);
1066 if (IS_ERR(entry))
1067 return PTR_ERR(entry);
1068
1069 err = audit_del_rule(entry);
1070 audit_log_rule_change("remove rule", &entry->rule, !err);
1071 audit_free_rule(entry);
1072 break;
1073 default:
1074 return -EINVAL;
1075 }
1076
1077 return err;
1078 }
1079
1080 /**
1081 * audit_list_rules_send - list the audit rules
1082 * @request_skb: skb of request we are replying to (used to target the reply)
1083 * @seq: netlink audit message sequence (serial) number
1084 */
1085 int audit_list_rules_send(struct sk_buff *request_skb, int seq)
1086 {
1087 u32 portid = NETLINK_CB(request_skb).portid;
1088 struct net *net = sock_net(NETLINK_CB(request_skb).sk);
1089 struct task_struct *tsk;
1090 struct audit_netlink_list *dest;
1091 int err = 0;
1092
1093 /* We can't just spew out the rules here because we might fill
1094 * the available socket buffer space and deadlock waiting for
1095 * auditctl to read from it... which isn't ever going to
1096 * happen if we're actually running in the context of auditctl
1097 * trying to _send_ the stuff */
1098
1099 dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL);
1100 if (!dest)
1101 return -ENOMEM;
1102 dest->net = get_net(net);
1103 dest->portid = portid;
1104 skb_queue_head_init(&dest->q);
1105
1106 mutex_lock(&audit_filter_mutex);
1107 audit_list_rules(portid, seq, &dest->q);
1108 mutex_unlock(&audit_filter_mutex);
1109
1110 tsk = kthread_run(audit_send_list, dest, "audit_send_list");
1111 if (IS_ERR(tsk)) {
1112 skb_queue_purge(&dest->q);
1113 kfree(dest);
1114 err = PTR_ERR(tsk);
1115 }
1116
1117 return err;
1118 }
1119
1120 int audit_comparator(u32 left, u32 op, u32 right)
1121 {
1122 switch (op) {
1123 case Audit_equal:
1124 return (left == right);
1125 case Audit_not_equal:
1126 return (left != right);
1127 case Audit_lt:
1128 return (left < right);
1129 case Audit_le:
1130 return (left <= right);
1131 case Audit_gt:
1132 return (left > right);
1133 case Audit_ge:
1134 return (left >= right);
1135 case Audit_bitmask:
1136 return (left & right);
1137 case Audit_bittest:
1138 return ((left & right) == right);
1139 default:
1140 BUG();
1141 return 0;
1142 }
1143 }
1144
1145 int audit_uid_comparator(kuid_t left, u32 op, kuid_t right)
1146 {
1147 switch (op) {
1148 case Audit_equal:
1149 return uid_eq(left, right);
1150 case Audit_not_equal:
1151 return !uid_eq(left, right);
1152 case Audit_lt:
1153 return uid_lt(left, right);
1154 case Audit_le:
1155 return uid_lte(left, right);
1156 case Audit_gt:
1157 return uid_gt(left, right);
1158 case Audit_ge:
1159 return uid_gte(left, right);
1160 case Audit_bitmask:
1161 case Audit_bittest:
1162 default:
1163 BUG();
1164 return 0;
1165 }
1166 }
1167
1168 int audit_gid_comparator(kgid_t left, u32 op, kgid_t right)
1169 {
1170 switch (op) {
1171 case Audit_equal:
1172 return gid_eq(left, right);
1173 case Audit_not_equal:
1174 return !gid_eq(left, right);
1175 case Audit_lt:
1176 return gid_lt(left, right);
1177 case Audit_le:
1178 return gid_lte(left, right);
1179 case Audit_gt:
1180 return gid_gt(left, right);
1181 case Audit_ge:
1182 return gid_gte(left, right);
1183 case Audit_bitmask:
1184 case Audit_bittest:
1185 default:
1186 BUG();
1187 return 0;
1188 }
1189 }
1190
1191 /**
1192 * parent_len - find the length of the parent portion of a pathname
1193 * @path: pathname of which to determine length
1194 */
1195 int parent_len(const char *path)
1196 {
1197 int plen;
1198 const char *p;
1199
1200 plen = strlen(path);
1201
1202 if (plen == 0)
1203 return plen;
1204
1205 /* disregard trailing slashes */
1206 p = path + plen - 1;
1207 while ((*p == '/') && (p > path))
1208 p--;
1209
1210 /* walk backward until we find the next slash or hit beginning */
1211 while ((*p != '/') && (p > path))
1212 p--;
1213
1214 /* did we find a slash? Then increment to include it in path */
1215 if (*p == '/')
1216 p++;
1217
1218 return p - path;
1219 }
1220
1221 /**
1222 * audit_compare_dname_path - compare given dentry name with last component in
1223 * given path. Return of 0 indicates a match.
1224 * @dname: dentry name that we're comparing
1225 * @path: full pathname that we're comparing
1226 * @parentlen: length of the parent if known. Passing in AUDIT_NAME_FULL
1227 * here indicates that we must compute this value.
1228 */
1229 int audit_compare_dname_path(const char *dname, const char *path, int parentlen)
1230 {
1231 int dlen, pathlen;
1232 const char *p;
1233
1234 dlen = strlen(dname);
1235 pathlen = strlen(path);
1236 if (pathlen < dlen)
1237 return 1;
1238
1239 parentlen = parentlen == AUDIT_NAME_FULL ? parent_len(path) : parentlen;
1240 if (pathlen - parentlen != dlen)
1241 return 1;
1242
1243 p = path + parentlen;
1244
1245 return strncmp(p, dname, dlen);
1246 }
1247
1248 static int audit_filter_user_rules(struct audit_krule *rule, int type,
1249 enum audit_state *state)
1250 {
1251 int i;
1252
1253 for (i = 0; i < rule->field_count; i++) {
1254 struct audit_field *f = &rule->fields[i];
1255 pid_t pid;
1256 int result = 0;
1257 u32 sid;
1258
1259 switch (f->type) {
1260 case AUDIT_PID:
1261 pid = task_pid_nr(current);
1262 result = audit_comparator(pid, f->op, f->val);
1263 break;
1264 case AUDIT_UID:
1265 result = audit_uid_comparator(current_uid(), f->op, f->uid);
1266 break;
1267 case AUDIT_GID:
1268 result = audit_gid_comparator(current_gid(), f->op, f->gid);
1269 break;
1270 case AUDIT_LOGINUID:
1271 result = audit_uid_comparator(audit_get_loginuid(current),
1272 f->op, f->uid);
1273 break;
1274 case AUDIT_LOGINUID_SET:
1275 result = audit_comparator(audit_loginuid_set(current),
1276 f->op, f->val);
1277 break;
1278 case AUDIT_MSGTYPE:
1279 result = audit_comparator(type, f->op, f->val);
1280 break;
1281 case AUDIT_SUBJ_USER:
1282 case AUDIT_SUBJ_ROLE:
1283 case AUDIT_SUBJ_TYPE:
1284 case AUDIT_SUBJ_SEN:
1285 case AUDIT_SUBJ_CLR:
1286 if (f->lsm_rule) {
1287 security_task_getsecid(current, &sid);
1288 result = security_audit_rule_match(sid,
1289 f->type,
1290 f->op,
1291 f->lsm_rule,
1292 NULL);
1293 }
1294 break;
1295 }
1296
1297 if (!result)
1298 return 0;
1299 }
1300 switch (rule->action) {
1301 case AUDIT_NEVER: *state = AUDIT_DISABLED; break;
1302 case AUDIT_ALWAYS: *state = AUDIT_RECORD_CONTEXT; break;
1303 }
1304 return 1;
1305 }
1306
1307 int audit_filter_user(int type)
1308 {
1309 enum audit_state state = AUDIT_DISABLED;
1310 struct audit_entry *e;
1311 int rc, ret;
1312
1313 ret = 1; /* Audit by default */
1314
1315 rcu_read_lock();
1316 list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_USER], list) {
1317 rc = audit_filter_user_rules(&e->rule, type, &state);
1318 if (rc) {
1319 if (rc > 0 && state == AUDIT_DISABLED)
1320 ret = 0;
1321 break;
1322 }
1323 }
1324 rcu_read_unlock();
1325
1326 return ret;
1327 }
1328
1329 int audit_filter_type(int type)
1330 {
1331 struct audit_entry *e;
1332 int result = 0;
1333
1334 rcu_read_lock();
1335 if (list_empty(&audit_filter_list[AUDIT_FILTER_TYPE]))
1336 goto unlock_and_return;
1337
1338 list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_TYPE],
1339 list) {
1340 int i;
1341 for (i = 0; i < e->rule.field_count; i++) {
1342 struct audit_field *f = &e->rule.fields[i];
1343 if (f->type == AUDIT_MSGTYPE) {
1344 result = audit_comparator(type, f->op, f->val);
1345 if (!result)
1346 break;
1347 }
1348 }
1349 if (result)
1350 goto unlock_and_return;
1351 }
1352 unlock_and_return:
1353 rcu_read_unlock();
1354 return result;
1355 }
1356
1357 static int update_lsm_rule(struct audit_krule *r)
1358 {
1359 struct audit_entry *entry = container_of(r, struct audit_entry, rule);
1360 struct audit_entry *nentry;
1361 int err = 0;
1362
1363 if (!security_audit_rule_known(r))
1364 return 0;
1365
1366 nentry = audit_dupe_rule(r);
1367 if (IS_ERR(nentry)) {
1368 /* save the first error encountered for the
1369 * return value */
1370 err = PTR_ERR(nentry);
1371 audit_panic("error updating LSM filters");
1372 if (r->watch)
1373 list_del(&r->rlist);
1374 list_del_rcu(&entry->list);
1375 list_del(&r->list);
1376 } else {
1377 if (r->watch || r->tree)
1378 list_replace_init(&r->rlist, &nentry->rule.rlist);
1379 list_replace_rcu(&entry->list, &nentry->list);
1380 list_replace(&r->list, &nentry->rule.list);
1381 }
1382 call_rcu(&entry->rcu, audit_free_rule_rcu);
1383
1384 return err;
1385 }
1386
1387 /* This function will re-initialize the lsm_rule field of all applicable rules.
1388 * It will traverse the filter lists serarching for rules that contain LSM
1389 * specific filter fields. When such a rule is found, it is copied, the
1390 * LSM field is re-initialized, and the old rule is replaced with the
1391 * updated rule. */
1392 int audit_update_lsm_rules(void)
1393 {
1394 struct audit_krule *r, *n;
1395 int i, err = 0;
1396
1397 /* audit_filter_mutex synchronizes the writers */
1398 mutex_lock(&audit_filter_mutex);
1399
1400 for (i = 0; i < AUDIT_NR_FILTERS; i++) {
1401 list_for_each_entry_safe(r, n, &audit_rules_list[i], list) {
1402 int res = update_lsm_rule(r);
1403 if (!err)
1404 err = res;
1405 }
1406 }
1407 mutex_unlock(&audit_filter_mutex);
1408
1409 return err;
1410 }
Linux with added FPC-III support