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Linux 3.12.39
[linux/fpc-iii.git] / kernel / auditfilter.c
blobdfd2f4af81a9d24ddc1f451ed40dc0a65ca2f07d
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 #include <linux/kernel.h>
23 #include <linux/audit.h>
24 #include <linux/kthread.h>
25 #include <linux/mutex.h>
26 #include <linux/fs.h>
27 #include <linux/namei.h>
28 #include <linux/netlink.h>
29 #include <linux/sched.h>
30 #include <linux/slab.h>
31 #include <linux/security.h>
32 #include "audit.h"
33
34 /*
35 * Locking model:
36 *
37 * audit_filter_mutex:
38 * Synchronizes writes and blocking reads of audit's filterlist
39 * data. Rcu is used to traverse the filterlist and access
40 * contents of structs audit_entry, audit_watch and opaque
41 * LSM rules during filtering. If modified, these structures
42 * must be copied and replace their counterparts in the filterlist.
43 * An audit_parent struct is not accessed during filtering, so may
44 * be written directly provided audit_filter_mutex is held.
45 */
46
47 /* Audit filter lists, defined in <linux/audit.h> */
48 struct list_head audit_filter_list[AUDIT_NR_FILTERS] = {
49 LIST_HEAD_INIT(audit_filter_list[0]),
50 LIST_HEAD_INIT(audit_filter_list[1]),
51 LIST_HEAD_INIT(audit_filter_list[2]),
52 LIST_HEAD_INIT(audit_filter_list[3]),
53 LIST_HEAD_INIT(audit_filter_list[4]),
54 LIST_HEAD_INIT(audit_filter_list[5]),
55 #if AUDIT_NR_FILTERS != 6
56 #error Fix audit_filter_list initialiser
57 #endif
58 };
59 static struct list_head audit_rules_list[AUDIT_NR_FILTERS] = {
60 LIST_HEAD_INIT(audit_rules_list[0]),
61 LIST_HEAD_INIT(audit_rules_list[1]),
62 LIST_HEAD_INIT(audit_rules_list[2]),
63 LIST_HEAD_INIT(audit_rules_list[3]),
64 LIST_HEAD_INIT(audit_rules_list[4]),
65 LIST_HEAD_INIT(audit_rules_list[5]),
66 };
67
68 DEFINE_MUTEX(audit_filter_mutex);
69
70 static inline void audit_free_rule(struct audit_entry *e)
71 {
72 int i;
73 struct audit_krule *erule = &e->rule;
74
75 /* some rules don't have associated watches */
76 if (erule->watch)
77 audit_put_watch(erule->watch);
78 if (erule->fields)
79 for (i = 0; i < erule->field_count; i++) {
80 struct audit_field *f = &erule->fields[i];
81 kfree(f->lsm_str);
82 security_audit_rule_free(f->lsm_rule);
83 }
84 kfree(erule->fields);
85 kfree(erule->filterkey);
86 kfree(e);
87 }
88
89 void audit_free_rule_rcu(struct rcu_head *head)
90 {
91 struct audit_entry *e = container_of(head, struct audit_entry, rcu);
92 audit_free_rule(e);
93 }
94
95 /* Initialize an audit filterlist entry. */
96 static inline struct audit_entry *audit_init_entry(u32 field_count)
97 {
98 struct audit_entry *entry;
99 struct audit_field *fields;
100
101 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
102 if (unlikely(!entry))
103 return NULL;
104
105 fields = kzalloc(sizeof(*fields) * field_count, GFP_KERNEL);
106 if (unlikely(!fields)) {
107 kfree(entry);
108 return NULL;
109 }
110 entry->rule.fields = fields;
111
112 return entry;
113 }
114
115 /* Unpack a filter field's string representation from user-space
116 * buffer. */
117 char *audit_unpack_string(void **bufp, size_t *remain, size_t len)
118 {
119 char *str;
120
121 if (!*bufp || (len == 0) || (len > *remain))
122 return ERR_PTR(-EINVAL);
123
124 /* Of the currently implemented string fields, PATH_MAX
125 * defines the longest valid length.
126 */
127 if (len > PATH_MAX)
128 return ERR_PTR(-ENAMETOOLONG);
129
130 str = kmalloc(len + 1, GFP_KERNEL);
131 if (unlikely(!str))
132 return ERR_PTR(-ENOMEM);
133
134 memcpy(str, *bufp, len);
135 str[len] = 0;
136 *bufp += len;
137 *remain -= len;
138
139 return str;
140 }
141
142 /* Translate an inode field to kernel respresentation. */
143 static inline int audit_to_inode(struct audit_krule *krule,
144 struct audit_field *f)
145 {
146 if (krule->listnr != AUDIT_FILTER_EXIT ||
147 krule->watch || krule->inode_f || krule->tree ||
148 (f->op != Audit_equal && f->op != Audit_not_equal))
149 return -EINVAL;
150
151 krule->inode_f = f;
152 return 0;
153 }
154
155 static __u32 *classes[AUDIT_SYSCALL_CLASSES];
156
157 int __init audit_register_class(int class, unsigned *list)
158 {
159 __u32 *p = kzalloc(AUDIT_BITMASK_SIZE * sizeof(__u32), GFP_KERNEL);
160 if (!p)
161 return -ENOMEM;
162 while (*list != ~0U) {
163 unsigned n = *list++;
164 if (n >= AUDIT_BITMASK_SIZE * 32 - AUDIT_SYSCALL_CLASSES) {
165 kfree(p);
166 return -EINVAL;
167 }
168 p[AUDIT_WORD(n)] |= AUDIT_BIT(n);
169 }
170 if (class >= AUDIT_SYSCALL_CLASSES || classes[class]) {
171 kfree(p);
172 return -EINVAL;
173 }
174 classes[class] = p;
175 return 0;
176 }
177
178 int audit_match_class(int class, unsigned syscall)
179 {
180 if (unlikely(syscall >= AUDIT_BITMASK_SIZE * 32))
181 return 0;
182 if (unlikely(class >= AUDIT_SYSCALL_CLASSES || !classes[class]))
183 return 0;
184 return classes[class][AUDIT_WORD(syscall)] & AUDIT_BIT(syscall);
185 }
186
187 #ifdef CONFIG_AUDITSYSCALL
188 static inline int audit_match_class_bits(int class, u32 *mask)
189 {
190 int i;
191
192 if (classes[class]) {
193 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
194 if (mask[i] & classes[class][i])
195 return 0;
196 }
197 return 1;
198 }
199
200 static int audit_match_signal(struct audit_entry *entry)
201 {
202 struct audit_field *arch = entry->rule.arch_f;
203
204 if (!arch) {
205 /* When arch is unspecified, we must check both masks on biarch
206 * as syscall number alone is ambiguous. */
207 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
208 entry->rule.mask) &&
209 audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
210 entry->rule.mask));
211 }
212
213 switch(audit_classify_arch(arch->val)) {
214 case 0: /* native */
215 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
216 entry->rule.mask));
217 case 1: /* 32bit on biarch */
218 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
219 entry->rule.mask));
220 default:
221 return 1;
222 }
223 }
224 #endif
225
226 /* Common user-space to kernel rule translation. */
227 static inline struct audit_entry *audit_to_entry_common(struct audit_rule *rule)
228 {
229 unsigned listnr;
230 struct audit_entry *entry;
231 int i, err;
232
233 err = -EINVAL;
234 listnr = rule->flags & ~AUDIT_FILTER_PREPEND;
235 switch(listnr) {
236 default:
237 goto exit_err;
238 #ifdef CONFIG_AUDITSYSCALL
239 case AUDIT_FILTER_ENTRY:
240 if (rule->action == AUDIT_ALWAYS)
241 goto exit_err;
242 case AUDIT_FILTER_EXIT:
243 case AUDIT_FILTER_TASK:
244 #endif
245 case AUDIT_FILTER_USER:
246 case AUDIT_FILTER_TYPE:
247 ;
248 }
249 if (unlikely(rule->action == AUDIT_POSSIBLE)) {
250 printk(KERN_ERR "AUDIT_POSSIBLE is deprecated\n");
251 goto exit_err;
252 }
253 if (rule->action != AUDIT_NEVER && rule->action != AUDIT_ALWAYS)
254 goto exit_err;
255 if (rule->field_count > AUDIT_MAX_FIELDS)
256 goto exit_err;
257
258 err = -ENOMEM;
259 entry = audit_init_entry(rule->field_count);
260 if (!entry)
261 goto exit_err;
262
263 entry->rule.flags = rule->flags & AUDIT_FILTER_PREPEND;
264 entry->rule.listnr = listnr;
265 entry->rule.action = rule->action;
266 entry->rule.field_count = rule->field_count;
267
268 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
269 entry->rule.mask[i] = rule->mask[i];
270
271 for (i = 0; i < AUDIT_SYSCALL_CLASSES; i++) {
272 int bit = AUDIT_BITMASK_SIZE * 32 - i - 1;
273 __u32 *p = &entry->rule.mask[AUDIT_WORD(bit)];
274 __u32 *class;
275
276 if (!(*p & AUDIT_BIT(bit)))
277 continue;
278 *p &= ~AUDIT_BIT(bit);
279 class = classes[i];
280 if (class) {
281 int j;
282 for (j = 0; j < AUDIT_BITMASK_SIZE; j++)
283 entry->rule.mask[j] |= class[j];
284 }
285 }
286
287 return entry;
288
289 exit_err:
290 return ERR_PTR(err);
291 }
292
293 static u32 audit_ops[] =
294 {
295 [Audit_equal] = AUDIT_EQUAL,
296 [Audit_not_equal] = AUDIT_NOT_EQUAL,
297 [Audit_bitmask] = AUDIT_BIT_MASK,
298 [Audit_bittest] = AUDIT_BIT_TEST,
299 [Audit_lt] = AUDIT_LESS_THAN,
300 [Audit_gt] = AUDIT_GREATER_THAN,
301 [Audit_le] = AUDIT_LESS_THAN_OR_EQUAL,
302 [Audit_ge] = AUDIT_GREATER_THAN_OR_EQUAL,
303 };
304
305 static u32 audit_to_op(u32 op)
306 {
307 u32 n;
308 for (n = Audit_equal; n < Audit_bad && audit_ops[n] != op; n++)
309 ;
310 return n;
311 }
312
313 /* check if an audit field is valid */
314 static int audit_field_valid(struct audit_entry *entry, struct audit_field *f)
315 {
316 switch(f->type) {
317 case AUDIT_MSGTYPE:
318 if (entry->rule.listnr != AUDIT_FILTER_TYPE &&
319 entry->rule.listnr != AUDIT_FILTER_USER)
320 return -EINVAL;
321 break;
322 };
323
324 switch(f->type) {
325 default:
326 return -EINVAL;
327 case AUDIT_UID:
328 case AUDIT_EUID:
329 case AUDIT_SUID:
330 case AUDIT_FSUID:
331 case AUDIT_LOGINUID:
332 case AUDIT_OBJ_UID:
333 case AUDIT_GID:
334 case AUDIT_EGID:
335 case AUDIT_SGID:
336 case AUDIT_FSGID:
337 case AUDIT_OBJ_GID:
338 case AUDIT_PID:
339 case AUDIT_PERS:
340 case AUDIT_MSGTYPE:
341 case AUDIT_PPID:
342 case AUDIT_DEVMAJOR:
343 case AUDIT_DEVMINOR:
344 case AUDIT_EXIT:
345 case AUDIT_SUCCESS:
346 /* bit ops are only useful on syscall args */
347 if (f->op == Audit_bitmask || f->op == Audit_bittest)
348 return -EINVAL;
349 break;
350 case AUDIT_ARG0:
351 case AUDIT_ARG1:
352 case AUDIT_ARG2:
353 case AUDIT_ARG3:
354 case AUDIT_SUBJ_USER:
355 case AUDIT_SUBJ_ROLE:
356 case AUDIT_SUBJ_TYPE:
357 case AUDIT_SUBJ_SEN:
358 case AUDIT_SUBJ_CLR:
359 case AUDIT_OBJ_USER:
360 case AUDIT_OBJ_ROLE:
361 case AUDIT_OBJ_TYPE:
362 case AUDIT_OBJ_LEV_LOW:
363 case AUDIT_OBJ_LEV_HIGH:
364 case AUDIT_WATCH:
365 case AUDIT_DIR:
366 case AUDIT_FILTERKEY:
367 break;
368 case AUDIT_LOGINUID_SET:
369 if ((f->val != 0) && (f->val != 1))
370 return -EINVAL;
371 /* FALL THROUGH */
372 case AUDIT_ARCH:
373 if (f->op != Audit_not_equal && f->op != Audit_equal)
374 return -EINVAL;
375 break;
376 case AUDIT_PERM:
377 if (f->val & ~15)
378 return -EINVAL;
379 break;
380 case AUDIT_FILETYPE:
381 if (f->val & ~S_IFMT)
382 return -EINVAL;
383 break;
384 case AUDIT_FIELD_COMPARE:
385 if (f->val > AUDIT_MAX_FIELD_COMPARE)
386 return -EINVAL;
387 break;
388 };
389 return 0;
390 }
391
392 /* Translate struct audit_rule_data to kernel's rule respresentation. */
393 static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
394 size_t datasz)
395 {
396 int err = 0;
397 struct audit_entry *entry;
398 void *bufp;
399 size_t remain = datasz - sizeof(struct audit_rule_data);
400 int i;
401 char *str;
402
403 entry = audit_to_entry_common((struct audit_rule *)data);
404 if (IS_ERR(entry))
405 goto exit_nofree;
406
407 bufp = data->buf;
408 entry->rule.vers_ops = 2;
409 for (i = 0; i < data->field_count; i++) {
410 struct audit_field *f = &entry->rule.fields[i];
411
412 err = -EINVAL;
413
414 f->op = audit_to_op(data->fieldflags[i]);
415 if (f->op == Audit_bad)
416 goto exit_free;
417
418 f->type = data->fields[i];
419 f->val = data->values[i];
420 f->uid = INVALID_UID;
421 f->gid = INVALID_GID;
422 f->lsm_str = NULL;
423 f->lsm_rule = NULL;
424
425 /* Support legacy tests for a valid loginuid */
426 if ((f->type == AUDIT_LOGINUID) && (f->val == AUDIT_UID_UNSET)) {
427 f->type = AUDIT_LOGINUID_SET;
428 f->val = 0;
429 entry->rule.pflags |= AUDIT_LOGINUID_LEGACY;
430 }
431
432 err = audit_field_valid(entry, f);
433 if (err)
434 goto exit_free;
435
436 err = -EINVAL;
437 switch (f->type) {
438 case AUDIT_LOGINUID:
439 case AUDIT_UID:
440 case AUDIT_EUID:
441 case AUDIT_SUID:
442 case AUDIT_FSUID:
443 case AUDIT_OBJ_UID:
444 f->uid = make_kuid(current_user_ns(), f->val);
445 if (!uid_valid(f->uid))
446 goto exit_free;
447 break;
448 case AUDIT_GID:
449 case AUDIT_EGID:
450 case AUDIT_SGID:
451 case AUDIT_FSGID:
452 case AUDIT_OBJ_GID:
453 f->gid = make_kgid(current_user_ns(), f->val);
454 if (!gid_valid(f->gid))
455 goto exit_free;
456 break;
457 case AUDIT_ARCH:
458 entry->rule.arch_f = f;
459 break;
460 case AUDIT_SUBJ_USER:
461 case AUDIT_SUBJ_ROLE:
462 case AUDIT_SUBJ_TYPE:
463 case AUDIT_SUBJ_SEN:
464 case AUDIT_SUBJ_CLR:
465 case AUDIT_OBJ_USER:
466 case AUDIT_OBJ_ROLE:
467 case AUDIT_OBJ_TYPE:
468 case AUDIT_OBJ_LEV_LOW:
469 case AUDIT_OBJ_LEV_HIGH:
470 str = audit_unpack_string(&bufp, &remain, f->val);
471 if (IS_ERR(str))
472 goto exit_free;
473 entry->rule.buflen += f->val;
474
475 err = security_audit_rule_init(f->type, f->op, str,
476 (void **)&f->lsm_rule);
477 /* Keep currently invalid fields around in case they
478 * become valid after a policy reload. */
479 if (err == -EINVAL) {
480 printk(KERN_WARNING "audit rule for LSM "
481 "\'%s\' is invalid\n", str);
482 err = 0;
483 }
484 if (err) {
485 kfree(str);
486 goto exit_free;
487 } else
488 f->lsm_str = str;
489 break;
490 case AUDIT_WATCH:
491 str = audit_unpack_string(&bufp, &remain, f->val);
492 if (IS_ERR(str))
493 goto exit_free;
494 entry->rule.buflen += f->val;
495
496 err = audit_to_watch(&entry->rule, str, f->val, f->op);
497 if (err) {
498 kfree(str);
499 goto exit_free;
500 }
501 break;
502 case AUDIT_DIR:
503 str = audit_unpack_string(&bufp, &remain, f->val);
504 if (IS_ERR(str))
505 goto exit_free;
506 entry->rule.buflen += f->val;
507
508 err = audit_make_tree(&entry->rule, str, f->op);
509 kfree(str);
510 if (err)
511 goto exit_free;
512 break;
513 case AUDIT_INODE:
514 err = audit_to_inode(&entry->rule, f);
515 if (err)
516 goto exit_free;
517 break;
518 case AUDIT_FILTERKEY:
519 if (entry->rule.filterkey || f->val > AUDIT_MAX_KEY_LEN)
520 goto exit_free;
521 str = audit_unpack_string(&bufp, &remain, f->val);
522 if (IS_ERR(str))
523 goto exit_free;
524 entry->rule.buflen += f->val;
525 entry->rule.filterkey = str;
526 break;
527 }
528 }
529
530 if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal)
531 entry->rule.inode_f = NULL;
532
533 exit_nofree:
534 return entry;
535
536 exit_free:
537 if (entry->rule.watch)
538 audit_put_watch(entry->rule.watch); /* matches initial get */
539 if (entry->rule.tree)
540 audit_put_tree(entry->rule.tree); /* that's the temporary one */
541 audit_free_rule(entry);
542 return ERR_PTR(err);
543 }
544
545 /* Pack a filter field's string representation into data block. */
546 static inline size_t audit_pack_string(void **bufp, const char *str)
547 {
548 size_t len = strlen(str);
549
550 memcpy(*bufp, str, len);
551 *bufp += len;
552
553 return len;
554 }
555
556 /* Translate kernel rule respresentation to struct audit_rule_data. */
557 static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule)
558 {
559 struct audit_rule_data *data;
560 void *bufp;
561 int i;
562
563 data = kmalloc(sizeof(*data) + krule->buflen, GFP_KERNEL);
564 if (unlikely(!data))
565 return NULL;
566 memset(data, 0, sizeof(*data));
567
568 data->flags = krule->flags | krule->listnr;
569 data->action = krule->action;
570 data->field_count = krule->field_count;
571 bufp = data->buf;
572 for (i = 0; i < data->field_count; i++) {
573 struct audit_field *f = &krule->fields[i];
574
575 data->fields[i] = f->type;
576 data->fieldflags[i] = audit_ops[f->op];
577 switch(f->type) {
578 case AUDIT_SUBJ_USER:
579 case AUDIT_SUBJ_ROLE:
580 case AUDIT_SUBJ_TYPE:
581 case AUDIT_SUBJ_SEN:
582 case AUDIT_SUBJ_CLR:
583 case AUDIT_OBJ_USER:
584 case AUDIT_OBJ_ROLE:
585 case AUDIT_OBJ_TYPE:
586 case AUDIT_OBJ_LEV_LOW:
587 case AUDIT_OBJ_LEV_HIGH:
588 data->buflen += data->values[i] =
589 audit_pack_string(&bufp, f->lsm_str);
590 break;
591 case AUDIT_WATCH:
592 data->buflen += data->values[i] =
593 audit_pack_string(&bufp,
594 audit_watch_path(krule->watch));
595 break;
596 case AUDIT_DIR:
597 data->buflen += data->values[i] =
598 audit_pack_string(&bufp,
599 audit_tree_path(krule->tree));
600 break;
601 case AUDIT_FILTERKEY:
602 data->buflen += data->values[i] =
603 audit_pack_string(&bufp, krule->filterkey);
604 break;
605 case AUDIT_LOGINUID_SET:
606 if (krule->pflags & AUDIT_LOGINUID_LEGACY && !f->val) {
607 data->fields[i] = AUDIT_LOGINUID;
608 data->values[i] = AUDIT_UID_UNSET;
609 break;
610 }
611 /* fallthrough if set */
612 default:
613 data->values[i] = f->val;
614 }
615 }
616 for (i = 0; i < AUDIT_BITMASK_SIZE; i++) data->mask[i] = krule->mask[i];
617
618 return data;
619 }
620
621 /* Compare two rules in kernel format. Considered success if rules
622 * don't match. */
623 static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
624 {
625 int i;
626
627 if (a->flags != b->flags ||
628 a->pflags != b->pflags ||
629 a->listnr != b->listnr ||
630 a->action != b->action ||
631 a->field_count != b->field_count)
632 return 1;
633
634 for (i = 0; i < a->field_count; i++) {
635 if (a->fields[i].type != b->fields[i].type ||
636 a->fields[i].op != b->fields[i].op)
637 return 1;
638
639 switch(a->fields[i].type) {
640 case AUDIT_SUBJ_USER:
641 case AUDIT_SUBJ_ROLE:
642 case AUDIT_SUBJ_TYPE:
643 case AUDIT_SUBJ_SEN:
644 case AUDIT_SUBJ_CLR:
645 case AUDIT_OBJ_USER:
646 case AUDIT_OBJ_ROLE:
647 case AUDIT_OBJ_TYPE:
648 case AUDIT_OBJ_LEV_LOW:
649 case AUDIT_OBJ_LEV_HIGH:
650 if (strcmp(a->fields[i].lsm_str, b->fields[i].lsm_str))
651 return 1;
652 break;
653 case AUDIT_WATCH:
654 if (strcmp(audit_watch_path(a->watch),
655 audit_watch_path(b->watch)))
656 return 1;
657 break;
658 case AUDIT_DIR:
659 if (strcmp(audit_tree_path(a->tree),
660 audit_tree_path(b->tree)))
661 return 1;
662 break;
663 case AUDIT_FILTERKEY:
664 /* both filterkeys exist based on above type compare */
665 if (strcmp(a->filterkey, b->filterkey))
666 return 1;
667 break;
668 case AUDIT_UID:
669 case AUDIT_EUID:
670 case AUDIT_SUID:
671 case AUDIT_FSUID:
672 case AUDIT_LOGINUID:
673 case AUDIT_OBJ_UID:
674 if (!uid_eq(a->fields[i].uid, b->fields[i].uid))
675 return 1;
676 break;
677 case AUDIT_GID:
678 case AUDIT_EGID:
679 case AUDIT_SGID:
680 case AUDIT_FSGID:
681 case AUDIT_OBJ_GID:
682 if (!gid_eq(a->fields[i].gid, b->fields[i].gid))
683 return 1;
684 break;
685 default:
686 if (a->fields[i].val != b->fields[i].val)
687 return 1;
688 }
689 }
690
691 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
692 if (a->mask[i] != b->mask[i])
693 return 1;
694
695 return 0;
696 }
697
698 /* Duplicate LSM field information. The lsm_rule is opaque, so must be
699 * re-initialized. */
700 static inline int audit_dupe_lsm_field(struct audit_field *df,
701 struct audit_field *sf)
702 {
703 int ret = 0;
704 char *lsm_str;
705
706 /* our own copy of lsm_str */
707 lsm_str = kstrdup(sf->lsm_str, GFP_KERNEL);
708 if (unlikely(!lsm_str))
709 return -ENOMEM;
710 df->lsm_str = lsm_str;
711
712 /* our own (refreshed) copy of lsm_rule */
713 ret = security_audit_rule_init(df->type, df->op, df->lsm_str,
714 (void **)&df->lsm_rule);
715 /* Keep currently invalid fields around in case they
716 * become valid after a policy reload. */
717 if (ret == -EINVAL) {
718 printk(KERN_WARNING "audit rule for LSM \'%s\' is "
719 "invalid\n", df->lsm_str);
720 ret = 0;
721 }
722
723 return ret;
724 }
725
726 /* Duplicate an audit rule. This will be a deep copy with the exception
727 * of the watch - that pointer is carried over. The LSM specific fields
728 * will be updated in the copy. The point is to be able to replace the old
729 * rule with the new rule in the filterlist, then free the old rule.
730 * The rlist element is undefined; list manipulations are handled apart from
731 * the initial copy. */
732 struct audit_entry *audit_dupe_rule(struct audit_krule *old)
733 {
734 u32 fcount = old->field_count;
735 struct audit_entry *entry;
736 struct audit_krule *new;
737 char *fk;
738 int i, err = 0;
739
740 entry = audit_init_entry(fcount);
741 if (unlikely(!entry))
742 return ERR_PTR(-ENOMEM);
743
744 new = &entry->rule;
745 new->vers_ops = old->vers_ops;
746 new->flags = old->flags;
747 new->pflags = old->pflags;
748 new->listnr = old->listnr;
749 new->action = old->action;
750 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
751 new->mask[i] = old->mask[i];
752 new->prio = old->prio;
753 new->buflen = old->buflen;
754 new->inode_f = old->inode_f;
755 new->field_count = old->field_count;
756
757 /*
758 * note that we are OK with not refcounting here; audit_match_tree()
759 * never dereferences tree and we can't get false positives there
760 * since we'd have to have rule gone from the list *and* removed
761 * before the chunks found by lookup had been allocated, i.e. before
762 * the beginning of list scan.
763 */
764 new->tree = old->tree;
765 memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount);
766
767 /* deep copy this information, updating the lsm_rule fields, because
768 * the originals will all be freed when the old rule is freed. */
769 for (i = 0; i < fcount; i++) {
770 switch (new->fields[i].type) {
771 case AUDIT_SUBJ_USER:
772 case AUDIT_SUBJ_ROLE:
773 case AUDIT_SUBJ_TYPE:
774 case AUDIT_SUBJ_SEN:
775 case AUDIT_SUBJ_CLR:
776 case AUDIT_OBJ_USER:
777 case AUDIT_OBJ_ROLE:
778 case AUDIT_OBJ_TYPE:
779 case AUDIT_OBJ_LEV_LOW:
780 case AUDIT_OBJ_LEV_HIGH:
781 err = audit_dupe_lsm_field(&new->fields[i],
782 &old->fields[i]);
783 break;
784 case AUDIT_FILTERKEY:
785 fk = kstrdup(old->filterkey, GFP_KERNEL);
786 if (unlikely(!fk))
787 err = -ENOMEM;
788 else
789 new->filterkey = fk;
790 }
791 if (err) {
792 audit_free_rule(entry);
793 return ERR_PTR(err);
794 }
795 }
796
797 if (old->watch) {
798 audit_get_watch(old->watch);
799 new->watch = old->watch;
800 }
801
802 return entry;
803 }
804
805 /* Find an existing audit rule.
806 * Caller must hold audit_filter_mutex to prevent stale rule data. */
807 static struct audit_entry *audit_find_rule(struct audit_entry *entry,
808 struct list_head **p)
809 {
810 struct audit_entry *e, *found = NULL;
811 struct list_head *list;
812 int h;
813
814 if (entry->rule.inode_f) {
815 h = audit_hash_ino(entry->rule.inode_f->val);
816 *p = list = &audit_inode_hash[h];
817 } else if (entry->rule.watch) {
818 /* we don't know the inode number, so must walk entire hash */
819 for (h = 0; h < AUDIT_INODE_BUCKETS; h++) {
820 list = &audit_inode_hash[h];
821 list_for_each_entry(e, list, list)
822 if (!audit_compare_rule(&entry->rule, &e->rule)) {
823 found = e;
824 goto out;
825 }
826 }
827 goto out;
828 } else {
829 *p = list = &audit_filter_list[entry->rule.listnr];
830 }
831
832 list_for_each_entry(e, list, list)
833 if (!audit_compare_rule(&entry->rule, &e->rule)) {
834 found = e;
835 goto out;
836 }
837
838 out:
839 return found;
840 }
841
842 static u64 prio_low = ~0ULL/2;
843 static u64 prio_high = ~0ULL/2 - 1;
844
845 /* Add rule to given filterlist if not a duplicate. */
846 static inline int audit_add_rule(struct audit_entry *entry)
847 {
848 struct audit_entry *e;
849 struct audit_watch *watch = entry->rule.watch;
850 struct audit_tree *tree = entry->rule.tree;
851 struct list_head *list;
852 int err;
853 #ifdef CONFIG_AUDITSYSCALL
854 int dont_count = 0;
855
856 /* If either of these, don't count towards total */
857 if (entry->rule.listnr == AUDIT_FILTER_USER ||
858 entry->rule.listnr == AUDIT_FILTER_TYPE)
859 dont_count = 1;
860 #endif
861
862 mutex_lock(&audit_filter_mutex);
863 e = audit_find_rule(entry, &list);
864 if (e) {
865 mutex_unlock(&audit_filter_mutex);
866 err = -EEXIST;
867 /* normally audit_add_tree_rule() will free it on failure */
868 if (tree)
869 audit_put_tree(tree);
870 goto error;
871 }
872
873 if (watch) {
874 /* audit_filter_mutex is dropped and re-taken during this call */
875 err = audit_add_watch(&entry->rule, &list);
876 if (err) {
877 mutex_unlock(&audit_filter_mutex);
878 /*
879 * normally audit_add_tree_rule() will free it
880 * on failure
881 */
882 if (tree)
883 audit_put_tree(tree);
884 goto error;
885 }
886 }
887 if (tree) {
888 err = audit_add_tree_rule(&entry->rule);
889 if (err) {
890 mutex_unlock(&audit_filter_mutex);
891 goto error;
892 }
893 }
894
895 entry->rule.prio = ~0ULL;
896 if (entry->rule.listnr == AUDIT_FILTER_EXIT) {
897 if (entry->rule.flags & AUDIT_FILTER_PREPEND)
898 entry->rule.prio = ++prio_high;
899 else
900 entry->rule.prio = --prio_low;
901 }
902
903 if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
904 list_add(&entry->rule.list,
905 &audit_rules_list[entry->rule.listnr]);
906 list_add_rcu(&entry->list, list);
907 entry->rule.flags &= ~AUDIT_FILTER_PREPEND;
908 } else {
909 list_add_tail(&entry->rule.list,
910 &audit_rules_list[entry->rule.listnr]);
911 list_add_tail_rcu(&entry->list, list);
912 }
913 #ifdef CONFIG_AUDITSYSCALL
914 if (!dont_count)
915 audit_n_rules++;
916
917 if (!audit_match_signal(entry))
918 audit_signals++;
919 #endif
920 mutex_unlock(&audit_filter_mutex);
921
922 return 0;
923
924 error:
925 if (watch)
926 audit_put_watch(watch); /* tmp watch, matches initial get */
927 return err;
928 }
929
930 /* Remove an existing rule from filterlist. */
931 static inline int audit_del_rule(struct audit_entry *entry)
932 {
933 struct audit_entry *e;
934 struct audit_watch *watch = entry->rule.watch;
935 struct audit_tree *tree = entry->rule.tree;
936 struct list_head *list;
937 int ret = 0;
938 #ifdef CONFIG_AUDITSYSCALL
939 int dont_count = 0;
940
941 /* If either of these, don't count towards total */
942 if (entry->rule.listnr == AUDIT_FILTER_USER ||
943 entry->rule.listnr == AUDIT_FILTER_TYPE)
944 dont_count = 1;
945 #endif
946
947 mutex_lock(&audit_filter_mutex);
948 e = audit_find_rule(entry, &list);
949 if (!e) {
950 mutex_unlock(&audit_filter_mutex);
951 ret = -ENOENT;
952 goto out;
953 }
954
955 if (e->rule.watch)
956 audit_remove_watch_rule(&e->rule);
957
958 if (e->rule.tree)
959 audit_remove_tree_rule(&e->rule);
960
961 list_del_rcu(&e->list);
962 list_del(&e->rule.list);
963 call_rcu(&e->rcu, audit_free_rule_rcu);
964
965 #ifdef CONFIG_AUDITSYSCALL
966 if (!dont_count)
967 audit_n_rules--;
968
969 if (!audit_match_signal(entry))
970 audit_signals--;
971 #endif
972 mutex_unlock(&audit_filter_mutex);
973
974 out:
975 if (watch)
976 audit_put_watch(watch); /* match initial get */
977 if (tree)
978 audit_put_tree(tree); /* that's the temporary one */
979
980 return ret;
981 }
982
983 /* List rules using struct audit_rule_data. */
984 static void audit_list_rules(int pid, int seq, struct sk_buff_head *q)
985 {
986 struct sk_buff *skb;
987 struct audit_krule *r;
988 int i;
989
990 /* This is a blocking read, so use audit_filter_mutex instead of rcu
991 * iterator to sync with list writers. */
992 for (i=0; i<AUDIT_NR_FILTERS; i++) {
993 list_for_each_entry(r, &audit_rules_list[i], list) {
994 struct audit_rule_data *data;
995
996 data = audit_krule_to_data(r);
997 if (unlikely(!data))
998 break;
999 skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 0, 1,
1000 data, sizeof(*data) + data->buflen);
1001 if (skb)
1002 skb_queue_tail(q, skb);
1003 kfree(data);
1004 }
1005 }
1006 skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);
1007 if (skb)
1008 skb_queue_tail(q, skb);
1009 }
1010
1011 /* Log rule additions and removals */
1012 static void audit_log_rule_change(char *action, struct audit_krule *rule, int res)
1013 {
1014 struct audit_buffer *ab;
1015 uid_t loginuid = from_kuid(&init_user_ns, audit_get_loginuid(current));
1016 u32 sessionid = audit_get_sessionid(current);
1017
1018 if (!audit_enabled)
1019 return;
1020
1021 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
1022 if (!ab)
1023 return;
1024 audit_log_format(ab, "auid=%u ses=%u" ,loginuid, sessionid);
1025 audit_log_task_context(ab);
1026 audit_log_format(ab, " op=");
1027 audit_log_string(ab, action);
1028 audit_log_key(ab, rule->filterkey);
1029 audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
1030 audit_log_end(ab);
1031 }
1032
1033 /**
1034 * audit_receive_filter - apply all rules to the specified message type
1035 * @type: audit message type
1036 * @pid: target pid for netlink audit messages
1037 * @seq: netlink audit message sequence (serial) number
1038 * @data: payload data
1039 * @datasz: size of payload data
1040 */
1041 int audit_receive_filter(int type, int pid, int seq, void *data, size_t datasz)
1042 {
1043 struct task_struct *tsk;
1044 struct audit_netlink_list *dest;
1045 int err = 0;
1046 struct audit_entry *entry;
1047
1048 switch (type) {
1049 case AUDIT_LIST_RULES:
1050 /* We can't just spew out the rules here because we might fill
1051 * the available socket buffer space and deadlock waiting for
1052 * auditctl to read from it... which isn't ever going to
1053 * happen if we're actually running in the context of auditctl
1054 * trying to _send_ the stuff */
1055
1056 dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL);
1057 if (!dest)
1058 return -ENOMEM;
1059 dest->pid = pid;
1060 skb_queue_head_init(&dest->q);
1061
1062 mutex_lock(&audit_filter_mutex);
1063 audit_list_rules(pid, seq, &dest->q);
1064 mutex_unlock(&audit_filter_mutex);
1065
1066 tsk = kthread_run(audit_send_list, dest, "audit_send_list");
1067 if (IS_ERR(tsk)) {
1068 skb_queue_purge(&dest->q);
1069 kfree(dest);
1070 err = PTR_ERR(tsk);
1071 }
1072 break;
1073 case AUDIT_ADD_RULE:
1074 entry = audit_data_to_entry(data, datasz);
1075 if (IS_ERR(entry))
1076 return PTR_ERR(entry);
1077
1078 err = audit_add_rule(entry);
1079 audit_log_rule_change("add rule", &entry->rule, !err);
1080 if (err)
1081 audit_free_rule(entry);
1082 break;
1083 case AUDIT_DEL_RULE:
1084 entry = audit_data_to_entry(data, datasz);
1085 if (IS_ERR(entry))
1086 return PTR_ERR(entry);
1087
1088 err = audit_del_rule(entry);
1089 audit_log_rule_change("remove rule", &entry->rule, !err);
1090 audit_free_rule(entry);
1091 break;
1092 default:
1093 return -EINVAL;
1094 }
1095
1096 return err;
1097 }
1098
1099 int audit_comparator(u32 left, u32 op, u32 right)
1100 {
1101 switch (op) {
1102 case Audit_equal:
1103 return (left == right);
1104 case Audit_not_equal:
1105 return (left != right);
1106 case Audit_lt:
1107 return (left < right);
1108 case Audit_le:
1109 return (left <= right);
1110 case Audit_gt:
1111 return (left > right);
1112 case Audit_ge:
1113 return (left >= right);
1114 case Audit_bitmask:
1115 return (left & right);
1116 case Audit_bittest:
1117 return ((left & right) == right);
1118 default:
1119 BUG();
1120 return 0;
1121 }
1122 }
1123
1124 int audit_uid_comparator(kuid_t left, u32 op, kuid_t right)
1125 {
1126 switch (op) {
1127 case Audit_equal:
1128 return uid_eq(left, right);
1129 case Audit_not_equal:
1130 return !uid_eq(left, right);
1131 case Audit_lt:
1132 return uid_lt(left, right);
1133 case Audit_le:
1134 return uid_lte(left, right);
1135 case Audit_gt:
1136 return uid_gt(left, right);
1137 case Audit_ge:
1138 return uid_gte(left, right);
1139 case Audit_bitmask:
1140 case Audit_bittest:
1141 default:
1142 BUG();
1143 return 0;
1144 }
1145 }
1146
1147 int audit_gid_comparator(kgid_t left, u32 op, kgid_t right)
1148 {
1149 switch (op) {
1150 case Audit_equal:
1151 return gid_eq(left, right);
1152 case Audit_not_equal:
1153 return !gid_eq(left, right);
1154 case Audit_lt:
1155 return gid_lt(left, right);
1156 case Audit_le:
1157 return gid_lte(left, right);
1158 case Audit_gt:
1159 return gid_gt(left, right);
1160 case Audit_ge:
1161 return gid_gte(left, right);
1162 case Audit_bitmask:
1163 case Audit_bittest:
1164 default:
1165 BUG();
1166 return 0;
1167 }
1168 }
1169
1170 /**
1171 * parent_len - find the length of the parent portion of a pathname
1172 * @path: pathname of which to determine length
1173 */
1174 int parent_len(const char *path)
1175 {
1176 int plen;
1177 const char *p;
1178
1179 plen = strlen(path);
1180
1181 if (plen == 0)
1182 return plen;
1183
1184 /* disregard trailing slashes */
1185 p = path + plen - 1;
1186 while ((*p == '/') && (p > path))
1187 p--;
1188
1189 /* walk backward until we find the next slash or hit beginning */
1190 while ((*p != '/') && (p > path))
1191 p--;
1192
1193 /* did we find a slash? Then increment to include it in path */
1194 if (*p == '/')
1195 p++;
1196
1197 return p - path;
1198 }
1199
1200 /**
1201 * audit_compare_dname_path - compare given dentry name with last component in
1202 * given path. Return of 0 indicates a match.
1203 * @dname: dentry name that we're comparing
1204 * @path: full pathname that we're comparing
1205 * @parentlen: length of the parent if known. Passing in AUDIT_NAME_FULL
1206 * here indicates that we must compute this value.
1207 */
1208 int audit_compare_dname_path(const char *dname, const char *path, int parentlen)
1209 {
1210 int dlen, pathlen;
1211 const char *p;
1212
1213 dlen = strlen(dname);
1214 pathlen = strlen(path);
1215 if (pathlen < dlen)
1216 return 1;
1217
1218 parentlen = parentlen == AUDIT_NAME_FULL ? parent_len(path) : parentlen;
1219 if (pathlen - parentlen != dlen)
1220 return 1;
1221
1222 p = path + parentlen;
1223
1224 return strncmp(p, dname, dlen);
1225 }
1226
1227 static int audit_filter_user_rules(struct audit_krule *rule, int type,
1228 enum audit_state *state)
1229 {
1230 int i;
1231
1232 for (i = 0; i < rule->field_count; i++) {
1233 struct audit_field *f = &rule->fields[i];
1234 int result = 0;
1235 u32 sid;
1236
1237 switch (f->type) {
1238 case AUDIT_PID:
1239 result = audit_comparator(task_pid_vnr(current), f->op, f->val);
1240 break;
1241 case AUDIT_UID:
1242 result = audit_uid_comparator(current_uid(), f->op, f->uid);
1243 break;
1244 case AUDIT_GID:
1245 result = audit_gid_comparator(current_gid(), f->op, f->gid);
1246 break;
1247 case AUDIT_LOGINUID:
1248 result = audit_uid_comparator(audit_get_loginuid(current),
1249 f->op, f->uid);
1250 break;
1251 case AUDIT_LOGINUID_SET:
1252 result = audit_comparator(audit_loginuid_set(current),
1253 f->op, f->val);
1254 break;
1255 case AUDIT_MSGTYPE:
1256 result = audit_comparator(type, f->op, f->val);
1257 break;
1258 case AUDIT_SUBJ_USER:
1259 case AUDIT_SUBJ_ROLE:
1260 case AUDIT_SUBJ_TYPE:
1261 case AUDIT_SUBJ_SEN:
1262 case AUDIT_SUBJ_CLR:
1263 if (f->lsm_rule) {
1264 security_task_getsecid(current, &sid);
1265 result = security_audit_rule_match(sid,
1266 f->type,
1267 f->op,
1268 f->lsm_rule,
1269 NULL);
1270 }
1271 break;
1272 }
1273
1274 if (!result)
1275 return 0;
1276 }
1277 switch (rule->action) {
1278 case AUDIT_NEVER: *state = AUDIT_DISABLED; break;
1279 case AUDIT_ALWAYS: *state = AUDIT_RECORD_CONTEXT; break;
1280 }
1281 return 1;
1282 }
1283
1284 int audit_filter_user(int type)
1285 {
1286 enum audit_state state = AUDIT_DISABLED;
1287 struct audit_entry *e;
1288 int ret = 1;
1289
1290 rcu_read_lock();
1291 list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_USER], list) {
1292 if (audit_filter_user_rules(&e->rule, type, &state)) {
1293 if (state == AUDIT_DISABLED)
1294 ret = 0;
1295 break;
1296 }
1297 }
1298 rcu_read_unlock();
1299
1300 return ret; /* Audit by default */
1301 }
1302
1303 int audit_filter_type(int type)
1304 {
1305 struct audit_entry *e;
1306 int result = 0;
1307
1308 rcu_read_lock();
1309 if (list_empty(&audit_filter_list[AUDIT_FILTER_TYPE]))
1310 goto unlock_and_return;
1311
1312 list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_TYPE],
1313 list) {
1314 int i;
1315 for (i = 0; i < e->rule.field_count; i++) {
1316 struct audit_field *f = &e->rule.fields[i];
1317 if (f->type == AUDIT_MSGTYPE) {
1318 result = audit_comparator(type, f->op, f->val);
1319 if (!result)
1320 break;
1321 }
1322 }
1323 if (result)
1324 goto unlock_and_return;
1325 }
1326 unlock_and_return:
1327 rcu_read_unlock();
1328 return result;
1329 }
1330
1331 static int update_lsm_rule(struct audit_krule *r)
1332 {
1333 struct audit_entry *entry = container_of(r, struct audit_entry, rule);
1334 struct audit_entry *nentry;
1335 int err = 0;
1336
1337 if (!security_audit_rule_known(r))
1338 return 0;
1339
1340 nentry = audit_dupe_rule(r);
1341 if (IS_ERR(nentry)) {
1342 /* save the first error encountered for the
1343 * return value */
1344 err = PTR_ERR(nentry);
1345 audit_panic("error updating LSM filters");
1346 if (r->watch)
1347 list_del(&r->rlist);
1348 list_del_rcu(&entry->list);
1349 list_del(&r->list);
1350 } else {
1351 if (r->watch || r->tree)
1352 list_replace_init(&r->rlist, &nentry->rule.rlist);
1353 list_replace_rcu(&entry->list, &nentry->list);
1354 list_replace(&r->list, &nentry->rule.list);
1355 }
1356 call_rcu(&entry->rcu, audit_free_rule_rcu);
1357
1358 return err;
1359 }
1360
1361 /* This function will re-initialize the lsm_rule field of all applicable rules.
1362 * It will traverse the filter lists serarching for rules that contain LSM
1363 * specific filter fields. When such a rule is found, it is copied, the
1364 * LSM field is re-initialized, and the old rule is replaced with the
1365 * updated rule. */
1366 int audit_update_lsm_rules(void)
1367 {
1368 struct audit_krule *r, *n;
1369 int i, err = 0;
1370
1371 /* audit_filter_mutex synchronizes the writers */
1372 mutex_lock(&audit_filter_mutex);
1373
1374 for (i = 0; i < AUDIT_NR_FILTERS; i++) {
1375 list_for_each_entry_safe(r, n, &audit_rules_list[i], list) {
1376 int res = update_lsm_rule(r);
1377 if (!err)
1378 err = res;
1379 }
1380 }
1381 mutex_unlock(&audit_filter_mutex);
1382
1383 return err;
1384 }
Linux with added FPC-III support