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SLUB: Get rid of dynamic DMA kmalloc cache allocation
[linux-2.6/x86.git] / kernel / auditfilter.c
bloba70604047f3c9061e81622a3b399b085fe5ac815
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/security.h>
31 #include "audit.h"
32
33 /*
34 * Locking model:
35 *
36 * audit_filter_mutex:
37 * Synchronizes writes and blocking reads of audit's filterlist
38 * data. Rcu is used to traverse the filterlist and access
39 * contents of structs audit_entry, audit_watch and opaque
40 * LSM rules during filtering. If modified, these structures
41 * must be copied and replace their counterparts in the filterlist.
42 * An audit_parent struct is not accessed during filtering, so may
43 * be written directly provided audit_filter_mutex is held.
44 */
45
46 /* Audit filter lists, defined in <linux/audit.h> */
47 struct list_head audit_filter_list[AUDIT_NR_FILTERS] = {
48 LIST_HEAD_INIT(audit_filter_list[0]),
49 LIST_HEAD_INIT(audit_filter_list[1]),
50 LIST_HEAD_INIT(audit_filter_list[2]),
51 LIST_HEAD_INIT(audit_filter_list[3]),
52 LIST_HEAD_INIT(audit_filter_list[4]),
53 LIST_HEAD_INIT(audit_filter_list[5]),
54 #if AUDIT_NR_FILTERS != 6
55 #error Fix audit_filter_list initialiser
56 #endif
57 };
58 static struct list_head audit_rules_list[AUDIT_NR_FILTERS] = {
59 LIST_HEAD_INIT(audit_rules_list[0]),
60 LIST_HEAD_INIT(audit_rules_list[1]),
61 LIST_HEAD_INIT(audit_rules_list[2]),
62 LIST_HEAD_INIT(audit_rules_list[3]),
63 LIST_HEAD_INIT(audit_rules_list[4]),
64 LIST_HEAD_INIT(audit_rules_list[5]),
65 };
66
67 DEFINE_MUTEX(audit_filter_mutex);
68
69 static inline void audit_free_rule(struct audit_entry *e)
70 {
71 int i;
72 struct audit_krule *erule = &e->rule;
73 /* some rules don't have associated watches */
74 if (erule->watch)
75 audit_put_watch(erule->watch);
76 if (erule->fields)
77 for (i = 0; i < erule->field_count; i++) {
78 struct audit_field *f = &erule->fields[i];
79 kfree(f->lsm_str);
80 security_audit_rule_free(f->lsm_rule);
81 }
82 kfree(erule->fields);
83 kfree(erule->filterkey);
84 kfree(e);
85 }
86
87 void audit_free_rule_rcu(struct rcu_head *head)
88 {
89 struct audit_entry *e = container_of(head, struct audit_entry, rcu);
90 audit_free_rule(e);
91 }
92
93 /* Initialize an audit filterlist entry. */
94 static inline struct audit_entry *audit_init_entry(u32 field_count)
95 {
96 struct audit_entry *entry;
97 struct audit_field *fields;
98
99 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
100 if (unlikely(!entry))
101 return NULL;
102
103 fields = kzalloc(sizeof(*fields) * field_count, GFP_KERNEL);
104 if (unlikely(!fields)) {
105 kfree(entry);
106 return NULL;
107 }
108 entry->rule.fields = fields;
109
110 return entry;
111 }
112
113 /* Unpack a filter field's string representation from user-space
114 * buffer. */
115 char *audit_unpack_string(void **bufp, size_t *remain, size_t len)
116 {
117 char *str;
118
119 if (!*bufp || (len == 0) || (len > *remain))
120 return ERR_PTR(-EINVAL);
121
122 /* Of the currently implemented string fields, PATH_MAX
123 * defines the longest valid length.
124 */
125 if (len > PATH_MAX)
126 return ERR_PTR(-ENAMETOOLONG);
127
128 str = kmalloc(len + 1, GFP_KERNEL);
129 if (unlikely(!str))
130 return ERR_PTR(-ENOMEM);
131
132 memcpy(str, *bufp, len);
133 str[len] = 0;
134 *bufp += len;
135 *remain -= len;
136
137 return str;
138 }
139
140 /* Translate an inode field to kernel respresentation. */
141 static inline int audit_to_inode(struct audit_krule *krule,
142 struct audit_field *f)
143 {
144 if (krule->listnr != AUDIT_FILTER_EXIT ||
145 krule->watch || krule->inode_f || krule->tree ||
146 (f->op != Audit_equal && f->op != Audit_not_equal))
147 return -EINVAL;
148
149 krule->inode_f = f;
150 return 0;
151 }
152
153 static __u32 *classes[AUDIT_SYSCALL_CLASSES];
154
155 int __init audit_register_class(int class, unsigned *list)
156 {
157 __u32 *p = kzalloc(AUDIT_BITMASK_SIZE * sizeof(__u32), GFP_KERNEL);
158 if (!p)
159 return -ENOMEM;
160 while (*list != ~0U) {
161 unsigned n = *list++;
162 if (n >= AUDIT_BITMASK_SIZE * 32 - AUDIT_SYSCALL_CLASSES) {
163 kfree(p);
164 return -EINVAL;
165 }
166 p[AUDIT_WORD(n)] |= AUDIT_BIT(n);
167 }
168 if (class >= AUDIT_SYSCALL_CLASSES || classes[class]) {
169 kfree(p);
170 return -EINVAL;
171 }
172 classes[class] = p;
173 return 0;
174 }
175
176 int audit_match_class(int class, unsigned syscall)
177 {
178 if (unlikely(syscall >= AUDIT_BITMASK_SIZE * 32))
179 return 0;
180 if (unlikely(class >= AUDIT_SYSCALL_CLASSES || !classes[class]))
181 return 0;
182 return classes[class][AUDIT_WORD(syscall)] & AUDIT_BIT(syscall);
183 }
184
185 #ifdef CONFIG_AUDITSYSCALL
186 static inline int audit_match_class_bits(int class, u32 *mask)
187 {
188 int i;
189
190 if (classes[class]) {
191 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
192 if (mask[i] & classes[class][i])
193 return 0;
194 }
195 return 1;
196 }
197
198 static int audit_match_signal(struct audit_entry *entry)
199 {
200 struct audit_field *arch = entry->rule.arch_f;
201
202 if (!arch) {
203 /* When arch is unspecified, we must check both masks on biarch
204 * as syscall number alone is ambiguous. */
205 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
206 entry->rule.mask) &&
207 audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
208 entry->rule.mask));
209 }
210
211 switch(audit_classify_arch(arch->val)) {
212 case 0: /* native */
213 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
214 entry->rule.mask));
215 case 1: /* 32bit on biarch */
216 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
217 entry->rule.mask));
218 default:
219 return 1;
220 }
221 }
222 #endif
223
224 /* Common user-space to kernel rule translation. */
225 static inline struct audit_entry *audit_to_entry_common(struct audit_rule *rule)
226 {
227 unsigned listnr;
228 struct audit_entry *entry;
229 int i, err;
230
231 err = -EINVAL;
232 listnr = rule->flags & ~AUDIT_FILTER_PREPEND;
233 switch(listnr) {
234 default:
235 goto exit_err;
236 case AUDIT_FILTER_USER:
237 case AUDIT_FILTER_TYPE:
238 #ifdef CONFIG_AUDITSYSCALL
239 case AUDIT_FILTER_ENTRY:
240 case AUDIT_FILTER_EXIT:
241 case AUDIT_FILTER_TASK:
242 #endif
243 ;
244 }
245 if (unlikely(rule->action == AUDIT_POSSIBLE)) {
246 printk(KERN_ERR "AUDIT_POSSIBLE is deprecated\n");
247 goto exit_err;
248 }
249 if (rule->action != AUDIT_NEVER && rule->action != AUDIT_ALWAYS)
250 goto exit_err;
251 if (rule->field_count > AUDIT_MAX_FIELDS)
252 goto exit_err;
253
254 err = -ENOMEM;
255 entry = audit_init_entry(rule->field_count);
256 if (!entry)
257 goto exit_err;
258
259 entry->rule.flags = rule->flags & AUDIT_FILTER_PREPEND;
260 entry->rule.listnr = listnr;
261 entry->rule.action = rule->action;
262 entry->rule.field_count = rule->field_count;
263
264 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
265 entry->rule.mask[i] = rule->mask[i];
266
267 for (i = 0; i < AUDIT_SYSCALL_CLASSES; i++) {
268 int bit = AUDIT_BITMASK_SIZE * 32 - i - 1;
269 __u32 *p = &entry->rule.mask[AUDIT_WORD(bit)];
270 __u32 *class;
271
272 if (!(*p & AUDIT_BIT(bit)))
273 continue;
274 *p &= ~AUDIT_BIT(bit);
275 class = classes[i];
276 if (class) {
277 int j;
278 for (j = 0; j < AUDIT_BITMASK_SIZE; j++)
279 entry->rule.mask[j] |= class[j];
280 }
281 }
282
283 return entry;
284
285 exit_err:
286 return ERR_PTR(err);
287 }
288
289 static u32 audit_ops[] =
290 {
291 [Audit_equal] = AUDIT_EQUAL,
292 [Audit_not_equal] = AUDIT_NOT_EQUAL,
293 [Audit_bitmask] = AUDIT_BIT_MASK,
294 [Audit_bittest] = AUDIT_BIT_TEST,
295 [Audit_lt] = AUDIT_LESS_THAN,
296 [Audit_gt] = AUDIT_GREATER_THAN,
297 [Audit_le] = AUDIT_LESS_THAN_OR_EQUAL,
298 [Audit_ge] = AUDIT_GREATER_THAN_OR_EQUAL,
299 };
300
301 static u32 audit_to_op(u32 op)
302 {
303 u32 n;
304 for (n = Audit_equal; n < Audit_bad && audit_ops[n] != op; n++)
305 ;
306 return n;
307 }
308
309
310 /* Translate struct audit_rule to kernel's rule respresentation.
311 * Exists for backward compatibility with userspace. */
312 static struct audit_entry *audit_rule_to_entry(struct audit_rule *rule)
313 {
314 struct audit_entry *entry;
315 int err = 0;
316 int i;
317
318 entry = audit_to_entry_common(rule);
319 if (IS_ERR(entry))
320 goto exit_nofree;
321
322 for (i = 0; i < rule->field_count; i++) {
323 struct audit_field *f = &entry->rule.fields[i];
324 u32 n;
325
326 n = rule->fields[i] & (AUDIT_NEGATE|AUDIT_OPERATORS);
327
328 /* Support for legacy operators where
329 * AUDIT_NEGATE bit signifies != and otherwise assumes == */
330 if (n & AUDIT_NEGATE)
331 f->op = Audit_not_equal;
332 else if (!n)
333 f->op = Audit_equal;
334 else
335 f->op = audit_to_op(n);
336
337 entry->rule.vers_ops = (n & AUDIT_OPERATORS) ? 2 : 1;
338
339 f->type = rule->fields[i] & ~(AUDIT_NEGATE|AUDIT_OPERATORS);
340 f->val = rule->values[i];
341
342 err = -EINVAL;
343 if (f->op == Audit_bad)
344 goto exit_free;
345
346 switch(f->type) {
347 default:
348 goto exit_free;
349 case AUDIT_PID:
350 case AUDIT_UID:
351 case AUDIT_EUID:
352 case AUDIT_SUID:
353 case AUDIT_FSUID:
354 case AUDIT_GID:
355 case AUDIT_EGID:
356 case AUDIT_SGID:
357 case AUDIT_FSGID:
358 case AUDIT_LOGINUID:
359 case AUDIT_PERS:
360 case AUDIT_MSGTYPE:
361 case AUDIT_PPID:
362 case AUDIT_DEVMAJOR:
363 case AUDIT_DEVMINOR:
364 case AUDIT_EXIT:
365 case AUDIT_SUCCESS:
366 /* bit ops are only useful on syscall args */
367 if (f->op == Audit_bitmask || f->op == Audit_bittest)
368 goto exit_free;
369 break;
370 case AUDIT_ARG0:
371 case AUDIT_ARG1:
372 case AUDIT_ARG2:
373 case AUDIT_ARG3:
374 break;
375 /* arch is only allowed to be = or != */
376 case AUDIT_ARCH:
377 if (f->op != Audit_not_equal && f->op != Audit_equal)
378 goto exit_free;
379 entry->rule.arch_f = f;
380 break;
381 case AUDIT_PERM:
382 if (f->val & ~15)
383 goto exit_free;
384 break;
385 case AUDIT_FILETYPE:
386 if ((f->val & ~S_IFMT) > S_IFMT)
387 goto exit_free;
388 break;
389 case AUDIT_INODE:
390 err = audit_to_inode(&entry->rule, f);
391 if (err)
392 goto exit_free;
393 break;
394 }
395 }
396
397 if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal)
398 entry->rule.inode_f = NULL;
399
400 exit_nofree:
401 return entry;
402
403 exit_free:
404 audit_free_rule(entry);
405 return ERR_PTR(err);
406 }
407
408 /* Translate struct audit_rule_data to kernel's rule respresentation. */
409 static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
410 size_t datasz)
411 {
412 int err = 0;
413 struct audit_entry *entry;
414 void *bufp;
415 size_t remain = datasz - sizeof(struct audit_rule_data);
416 int i;
417 char *str;
418
419 entry = audit_to_entry_common((struct audit_rule *)data);
420 if (IS_ERR(entry))
421 goto exit_nofree;
422
423 bufp = data->buf;
424 entry->rule.vers_ops = 2;
425 for (i = 0; i < data->field_count; i++) {
426 struct audit_field *f = &entry->rule.fields[i];
427
428 err = -EINVAL;
429
430 f->op = audit_to_op(data->fieldflags[i]);
431 if (f->op == Audit_bad)
432 goto exit_free;
433
434 f->type = data->fields[i];
435 f->val = data->values[i];
436 f->lsm_str = NULL;
437 f->lsm_rule = NULL;
438 switch(f->type) {
439 case AUDIT_PID:
440 case AUDIT_UID:
441 case AUDIT_EUID:
442 case AUDIT_SUID:
443 case AUDIT_FSUID:
444 case AUDIT_GID:
445 case AUDIT_EGID:
446 case AUDIT_SGID:
447 case AUDIT_FSGID:
448 case AUDIT_LOGINUID:
449 case AUDIT_PERS:
450 case AUDIT_MSGTYPE:
451 case AUDIT_PPID:
452 case AUDIT_DEVMAJOR:
453 case AUDIT_DEVMINOR:
454 case AUDIT_EXIT:
455 case AUDIT_SUCCESS:
456 case AUDIT_ARG0:
457 case AUDIT_ARG1:
458 case AUDIT_ARG2:
459 case AUDIT_ARG3:
460 break;
461 case AUDIT_ARCH:
462 entry->rule.arch_f = f;
463 break;
464 case AUDIT_SUBJ_USER:
465 case AUDIT_SUBJ_ROLE:
466 case AUDIT_SUBJ_TYPE:
467 case AUDIT_SUBJ_SEN:
468 case AUDIT_SUBJ_CLR:
469 case AUDIT_OBJ_USER:
470 case AUDIT_OBJ_ROLE:
471 case AUDIT_OBJ_TYPE:
472 case AUDIT_OBJ_LEV_LOW:
473 case AUDIT_OBJ_LEV_HIGH:
474 str = audit_unpack_string(&bufp, &remain, f->val);
475 if (IS_ERR(str))
476 goto exit_free;
477 entry->rule.buflen += f->val;
478
479 err = security_audit_rule_init(f->type, f->op, str,
480 (void **)&f->lsm_rule);
481 /* Keep currently invalid fields around in case they
482 * become valid after a policy reload. */
483 if (err == -EINVAL) {
484 printk(KERN_WARNING "audit rule for LSM "
485 "\'%s\' is invalid\n", str);
486 err = 0;
487 }
488 if (err) {
489 kfree(str);
490 goto exit_free;
491 } else
492 f->lsm_str = str;
493 break;
494 case AUDIT_WATCH:
495 str = audit_unpack_string(&bufp, &remain, f->val);
496 if (IS_ERR(str))
497 goto exit_free;
498 entry->rule.buflen += f->val;
499
500 err = audit_to_watch(&entry->rule, str, f->val, f->op);
501 if (err) {
502 kfree(str);
503 goto exit_free;
504 }
505 break;
506 case AUDIT_DIR:
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_make_tree(&entry->rule, str, f->op);
513 kfree(str);
514 if (err)
515 goto exit_free;
516 break;
517 case AUDIT_INODE:
518 err = audit_to_inode(&entry->rule, f);
519 if (err)
520 goto exit_free;
521 break;
522 case AUDIT_FILTERKEY:
523 err = -EINVAL;
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 case AUDIT_PERM:
533 if (f->val & ~15)
534 goto exit_free;
535 break;
536 case AUDIT_FILETYPE:
537 if ((f->val & ~S_IFMT) > S_IFMT)
538 goto exit_free;
539 break;
540 default:
541 goto exit_free;
542 }
543 }
544
545 if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal)
546 entry->rule.inode_f = NULL;
547
548 exit_nofree:
549 return entry;
550
551 exit_free:
552 audit_free_rule(entry);
553 return ERR_PTR(err);
554 }
555
556 /* Pack a filter field's string representation into data block. */
557 static inline size_t audit_pack_string(void **bufp, const char *str)
558 {
559 size_t len = strlen(str);
560
561 memcpy(*bufp, str, len);
562 *bufp += len;
563
564 return len;
565 }
566
567 /* Translate kernel rule respresentation to struct audit_rule.
568 * Exists for backward compatibility with userspace. */
569 static struct audit_rule *audit_krule_to_rule(struct audit_krule *krule)
570 {
571 struct audit_rule *rule;
572 int i;
573
574 rule = kzalloc(sizeof(*rule), GFP_KERNEL);
575 if (unlikely(!rule))
576 return NULL;
577
578 rule->flags = krule->flags | krule->listnr;
579 rule->action = krule->action;
580 rule->field_count = krule->field_count;
581 for (i = 0; i < rule->field_count; i++) {
582 rule->values[i] = krule->fields[i].val;
583 rule->fields[i] = krule->fields[i].type;
584
585 if (krule->vers_ops == 1) {
586 if (krule->fields[i].op == Audit_not_equal)
587 rule->fields[i] |= AUDIT_NEGATE;
588 } else {
589 rule->fields[i] |= audit_ops[krule->fields[i].op];
590 }
591 }
592 for (i = 0; i < AUDIT_BITMASK_SIZE; i++) rule->mask[i] = krule->mask[i];
593
594 return rule;
595 }
596
597 /* Translate kernel rule respresentation to struct audit_rule_data. */
598 static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule)
599 {
600 struct audit_rule_data *data;
601 void *bufp;
602 int i;
603
604 data = kmalloc(sizeof(*data) + krule->buflen, GFP_KERNEL);
605 if (unlikely(!data))
606 return NULL;
607 memset(data, 0, sizeof(*data));
608
609 data->flags = krule->flags | krule->listnr;
610 data->action = krule->action;
611 data->field_count = krule->field_count;
612 bufp = data->buf;
613 for (i = 0; i < data->field_count; i++) {
614 struct audit_field *f = &krule->fields[i];
615
616 data->fields[i] = f->type;
617 data->fieldflags[i] = audit_ops[f->op];
618 switch(f->type) {
619 case AUDIT_SUBJ_USER:
620 case AUDIT_SUBJ_ROLE:
621 case AUDIT_SUBJ_TYPE:
622 case AUDIT_SUBJ_SEN:
623 case AUDIT_SUBJ_CLR:
624 case AUDIT_OBJ_USER:
625 case AUDIT_OBJ_ROLE:
626 case AUDIT_OBJ_TYPE:
627 case AUDIT_OBJ_LEV_LOW:
628 case AUDIT_OBJ_LEV_HIGH:
629 data->buflen += data->values[i] =
630 audit_pack_string(&bufp, f->lsm_str);
631 break;
632 case AUDIT_WATCH:
633 data->buflen += data->values[i] =
634 audit_pack_string(&bufp,
635 audit_watch_path(krule->watch));
636 break;
637 case AUDIT_DIR:
638 data->buflen += data->values[i] =
639 audit_pack_string(&bufp,
640 audit_tree_path(krule->tree));
641 break;
642 case AUDIT_FILTERKEY:
643 data->buflen += data->values[i] =
644 audit_pack_string(&bufp, krule->filterkey);
645 break;
646 default:
647 data->values[i] = f->val;
648 }
649 }
650 for (i = 0; i < AUDIT_BITMASK_SIZE; i++) data->mask[i] = krule->mask[i];
651
652 return data;
653 }
654
655 /* Compare two rules in kernel format. Considered success if rules
656 * don't match. */
657 static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
658 {
659 int i;
660
661 if (a->flags != b->flags ||
662 a->listnr != b->listnr ||
663 a->action != b->action ||
664 a->field_count != b->field_count)
665 return 1;
666
667 for (i = 0; i < a->field_count; i++) {
668 if (a->fields[i].type != b->fields[i].type ||
669 a->fields[i].op != b->fields[i].op)
670 return 1;
671
672 switch(a->fields[i].type) {
673 case AUDIT_SUBJ_USER:
674 case AUDIT_SUBJ_ROLE:
675 case AUDIT_SUBJ_TYPE:
676 case AUDIT_SUBJ_SEN:
677 case AUDIT_SUBJ_CLR:
678 case AUDIT_OBJ_USER:
679 case AUDIT_OBJ_ROLE:
680 case AUDIT_OBJ_TYPE:
681 case AUDIT_OBJ_LEV_LOW:
682 case AUDIT_OBJ_LEV_HIGH:
683 if (strcmp(a->fields[i].lsm_str, b->fields[i].lsm_str))
684 return 1;
685 break;
686 case AUDIT_WATCH:
687 if (strcmp(audit_watch_path(a->watch),
688 audit_watch_path(b->watch)))
689 return 1;
690 break;
691 case AUDIT_DIR:
692 if (strcmp(audit_tree_path(a->tree),
693 audit_tree_path(b->tree)))
694 return 1;
695 break;
696 case AUDIT_FILTERKEY:
697 /* both filterkeys exist based on above type compare */
698 if (strcmp(a->filterkey, b->filterkey))
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 printk(KERN_WARNING "audit rule for LSM \'%s\' is "
735 "invalid\n", 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 struct audit_watch *watch)
750 {
751 u32 fcount = old->field_count;
752 struct audit_entry *entry;
753 struct audit_krule *new;
754 char *fk;
755 int i, err = 0;
756
757 entry = audit_init_entry(fcount);
758 if (unlikely(!entry))
759 return ERR_PTR(-ENOMEM);
760
761 new = &entry->rule;
762 new->vers_ops = old->vers_ops;
763 new->flags = old->flags;
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->watch = NULL;
772 new->field_count = old->field_count;
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 (watch) {
814 audit_get_watch(watch);
815 new->watch = 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 h, 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);
892 if (err) {
893 mutex_unlock(&audit_filter_mutex);
894 goto error;
895 }
896 /* entry->rule.watch may have changed during audit_add_watch() */
897 watch = entry->rule.watch;
898 h = audit_hash_ino((u32)audit_watch_inode(watch));
899 list = &audit_inode_hash[h];
900 }
901 if (tree) {
902 err = audit_add_tree_rule(&entry->rule);
903 if (err) {
904 mutex_unlock(&audit_filter_mutex);
905 goto error;
906 }
907 }
908
909 entry->rule.prio = ~0ULL;
910 if (entry->rule.listnr == AUDIT_FILTER_EXIT) {
911 if (entry->rule.flags & AUDIT_FILTER_PREPEND)
912 entry->rule.prio = ++prio_high;
913 else
914 entry->rule.prio = --prio_low;
915 }
916
917 if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
918 list_add(&entry->rule.list,
919 &audit_rules_list[entry->rule.listnr]);
920 list_add_rcu(&entry->list, list);
921 entry->rule.flags &= ~AUDIT_FILTER_PREPEND;
922 } else {
923 list_add_tail(&entry->rule.list,
924 &audit_rules_list[entry->rule.listnr]);
925 list_add_tail_rcu(&entry->list, list);
926 }
927 #ifdef CONFIG_AUDITSYSCALL
928 if (!dont_count)
929 audit_n_rules++;
930
931 if (!audit_match_signal(entry))
932 audit_signals++;
933 #endif
934 mutex_unlock(&audit_filter_mutex);
935
936 return 0;
937
938 error:
939 if (watch)
940 audit_put_watch(watch); /* tmp watch, matches initial get */
941 return err;
942 }
943
944 /* Remove an existing rule from filterlist. */
945 static inline int audit_del_rule(struct audit_entry *entry)
946 {
947 struct audit_entry *e;
948 struct audit_watch *watch = entry->rule.watch;
949 struct audit_tree *tree = entry->rule.tree;
950 struct list_head *list;
951 LIST_HEAD(inotify_list);
952 int ret = 0;
953 #ifdef CONFIG_AUDITSYSCALL
954 int dont_count = 0;
955
956 /* If either of these, don't count towards total */
957 if (entry->rule.listnr == AUDIT_FILTER_USER ||
958 entry->rule.listnr == AUDIT_FILTER_TYPE)
959 dont_count = 1;
960 #endif
961
962 mutex_lock(&audit_filter_mutex);
963 e = audit_find_rule(entry, &list);
964 if (!e) {
965 mutex_unlock(&audit_filter_mutex);
966 ret = -ENOENT;
967 goto out;
968 }
969
970 if (e->rule.watch)
971 audit_remove_watch_rule(&e->rule, &inotify_list);
972
973 if (e->rule.tree)
974 audit_remove_tree_rule(&e->rule);
975
976 list_del_rcu(&e->list);
977 list_del(&e->rule.list);
978 call_rcu(&e->rcu, audit_free_rule_rcu);
979
980 #ifdef CONFIG_AUDITSYSCALL
981 if (!dont_count)
982 audit_n_rules--;
983
984 if (!audit_match_signal(entry))
985 audit_signals--;
986 #endif
987 mutex_unlock(&audit_filter_mutex);
988
989 if (!list_empty(&inotify_list))
990 audit_inotify_unregister(&inotify_list);
991
992 out:
993 if (watch)
994 audit_put_watch(watch); /* match initial get */
995 if (tree)
996 audit_put_tree(tree); /* that's the temporary one */
997
998 return ret;
999 }
1000
1001 /* List rules using struct audit_rule. Exists for backward
1002 * compatibility with userspace. */
1003 static void audit_list(int pid, int seq, struct sk_buff_head *q)
1004 {
1005 struct sk_buff *skb;
1006 struct audit_krule *r;
1007 int i;
1008
1009 /* This is a blocking read, so use audit_filter_mutex instead of rcu
1010 * iterator to sync with list writers. */
1011 for (i=0; i<AUDIT_NR_FILTERS; i++) {
1012 list_for_each_entry(r, &audit_rules_list[i], list) {
1013 struct audit_rule *rule;
1014
1015 rule = audit_krule_to_rule(r);
1016 if (unlikely(!rule))
1017 break;
1018 skb = audit_make_reply(pid, seq, AUDIT_LIST, 0, 1,
1019 rule, sizeof(*rule));
1020 if (skb)
1021 skb_queue_tail(q, skb);
1022 kfree(rule);
1023 }
1024 }
1025 skb = audit_make_reply(pid, seq, AUDIT_LIST, 1, 1, NULL, 0);
1026 if (skb)
1027 skb_queue_tail(q, skb);
1028 }
1029
1030 /* List rules using struct audit_rule_data. */
1031 static void audit_list_rules(int pid, int seq, struct sk_buff_head *q)
1032 {
1033 struct sk_buff *skb;
1034 struct audit_krule *r;
1035 int i;
1036
1037 /* This is a blocking read, so use audit_filter_mutex instead of rcu
1038 * iterator to sync with list writers. */
1039 for (i=0; i<AUDIT_NR_FILTERS; i++) {
1040 list_for_each_entry(r, &audit_rules_list[i], list) {
1041 struct audit_rule_data *data;
1042
1043 data = audit_krule_to_data(r);
1044 if (unlikely(!data))
1045 break;
1046 skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 0, 1,
1047 data, sizeof(*data) + data->buflen);
1048 if (skb)
1049 skb_queue_tail(q, skb);
1050 kfree(data);
1051 }
1052 }
1053 skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);
1054 if (skb)
1055 skb_queue_tail(q, skb);
1056 }
1057
1058 /* Log rule additions and removals */
1059 static void audit_log_rule_change(uid_t loginuid, u32 sessionid, u32 sid,
1060 char *action, struct audit_krule *rule,
1061 int res)
1062 {
1063 struct audit_buffer *ab;
1064
1065 if (!audit_enabled)
1066 return;
1067
1068 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
1069 if (!ab)
1070 return;
1071 audit_log_format(ab, "auid=%u ses=%u", loginuid, sessionid);
1072 if (sid) {
1073 char *ctx = NULL;
1074 u32 len;
1075 if (security_secid_to_secctx(sid, &ctx, &len))
1076 audit_log_format(ab, " ssid=%u", sid);
1077 else {
1078 audit_log_format(ab, " subj=%s", ctx);
1079 security_release_secctx(ctx, len);
1080 }
1081 }
1082 audit_log_format(ab, " op=");
1083 audit_log_string(ab, action);
1084 audit_log_key(ab, rule->filterkey);
1085 audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
1086 audit_log_end(ab);
1087 }
1088
1089 /**
1090 * audit_receive_filter - apply all rules to the specified message type
1091 * @type: audit message type
1092 * @pid: target pid for netlink audit messages
1093 * @uid: target uid for netlink audit messages
1094 * @seq: netlink audit message sequence (serial) number
1095 * @data: payload data
1096 * @datasz: size of payload data
1097 * @loginuid: loginuid of sender
1098 * @sessionid: sessionid for netlink audit message
1099 * @sid: SE Linux Security ID of sender
1100 */
1101 int audit_receive_filter(int type, int pid, int uid, int seq, void *data,
1102 size_t datasz, uid_t loginuid, u32 sessionid, u32 sid)
1103 {
1104 struct task_struct *tsk;
1105 struct audit_netlink_list *dest;
1106 int err = 0;
1107 struct audit_entry *entry;
1108
1109 switch (type) {
1110 case AUDIT_LIST:
1111 case AUDIT_LIST_RULES:
1112 /* We can't just spew out the rules here because we might fill
1113 * the available socket buffer space and deadlock waiting for
1114 * auditctl to read from it... which isn't ever going to
1115 * happen if we're actually running in the context of auditctl
1116 * trying to _send_ the stuff */
1117
1118 dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL);
1119 if (!dest)
1120 return -ENOMEM;
1121 dest->pid = pid;
1122 skb_queue_head_init(&dest->q);
1123
1124 mutex_lock(&audit_filter_mutex);
1125 if (type == AUDIT_LIST)
1126 audit_list(pid, seq, &dest->q);
1127 else
1128 audit_list_rules(pid, seq, &dest->q);
1129 mutex_unlock(&audit_filter_mutex);
1130
1131 tsk = kthread_run(audit_send_list, dest, "audit_send_list");
1132 if (IS_ERR(tsk)) {
1133 skb_queue_purge(&dest->q);
1134 kfree(dest);
1135 err = PTR_ERR(tsk);
1136 }
1137 break;
1138 case AUDIT_ADD:
1139 case AUDIT_ADD_RULE:
1140 if (type == AUDIT_ADD)
1141 entry = audit_rule_to_entry(data);
1142 else
1143 entry = audit_data_to_entry(data, datasz);
1144 if (IS_ERR(entry))
1145 return PTR_ERR(entry);
1146
1147 err = audit_add_rule(entry);
1148 audit_log_rule_change(loginuid, sessionid, sid, "add rule",
1149 &entry->rule, !err);
1150
1151 if (err)
1152 audit_free_rule(entry);
1153 break;
1154 case AUDIT_DEL:
1155 case AUDIT_DEL_RULE:
1156 if (type == AUDIT_DEL)
1157 entry = audit_rule_to_entry(data);
1158 else
1159 entry = audit_data_to_entry(data, datasz);
1160 if (IS_ERR(entry))
1161 return PTR_ERR(entry);
1162
1163 err = audit_del_rule(entry);
1164 audit_log_rule_change(loginuid, sessionid, sid, "remove rule",
1165 &entry->rule, !err);
1166
1167 audit_free_rule(entry);
1168 break;
1169 default:
1170 return -EINVAL;
1171 }
1172
1173 return err;
1174 }
1175
1176 int audit_comparator(u32 left, u32 op, u32 right)
1177 {
1178 switch (op) {
1179 case Audit_equal:
1180 return (left == right);
1181 case Audit_not_equal:
1182 return (left != right);
1183 case Audit_lt:
1184 return (left < right);
1185 case Audit_le:
1186 return (left <= right);
1187 case Audit_gt:
1188 return (left > right);
1189 case Audit_ge:
1190 return (left >= right);
1191 case Audit_bitmask:
1192 return (left & right);
1193 case Audit_bittest:
1194 return ((left & right) == right);
1195 default:
1196 BUG();
1197 return 0;
1198 }
1199 }
1200
1201 /* Compare given dentry name with last component in given path,
1202 * return of 0 indicates a match. */
1203 int audit_compare_dname_path(const char *dname, const char *path,
1204 int *dirlen)
1205 {
1206 int dlen, plen;
1207 const char *p;
1208
1209 if (!dname || !path)
1210 return 1;
1211
1212 dlen = strlen(dname);
1213 plen = strlen(path);
1214 if (plen < dlen)
1215 return 1;
1216
1217 /* disregard trailing slashes */
1218 p = path + plen - 1;
1219 while ((*p == '/') && (p > path))
1220 p--;
1221
1222 /* find last path component */
1223 p = p - dlen + 1;
1224 if (p < path)
1225 return 1;
1226 else if (p > path) {
1227 if (*--p != '/')
1228 return 1;
1229 else
1230 p++;
1231 }
1232
1233 /* return length of path's directory component */
1234 if (dirlen)
1235 *dirlen = p - path;
1236 return strncmp(p, dname, dlen);
1237 }
1238
1239 static int audit_filter_user_rules(struct netlink_skb_parms *cb,
1240 struct audit_krule *rule,
1241 enum audit_state *state)
1242 {
1243 int i;
1244
1245 for (i = 0; i < rule->field_count; i++) {
1246 struct audit_field *f = &rule->fields[i];
1247 int result = 0;
1248
1249 switch (f->type) {
1250 case AUDIT_PID:
1251 result = audit_comparator(cb->creds.pid, f->op, f->val);
1252 break;
1253 case AUDIT_UID:
1254 result = audit_comparator(cb->creds.uid, f->op, f->val);
1255 break;
1256 case AUDIT_GID:
1257 result = audit_comparator(cb->creds.gid, f->op, f->val);
1258 break;
1259 case AUDIT_LOGINUID:
1260 result = audit_comparator(cb->loginuid, f->op, f->val);
1261 break;
1262 }
1263
1264 if (!result)
1265 return 0;
1266 }
1267 switch (rule->action) {
1268 case AUDIT_NEVER: *state = AUDIT_DISABLED; break;
1269 case AUDIT_ALWAYS: *state = AUDIT_RECORD_CONTEXT; break;
1270 }
1271 return 1;
1272 }
1273
1274 int audit_filter_user(struct netlink_skb_parms *cb)
1275 {
1276 enum audit_state state = AUDIT_DISABLED;
1277 struct audit_entry *e;
1278 int ret = 1;
1279
1280 rcu_read_lock();
1281 list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_USER], list) {
1282 if (audit_filter_user_rules(cb, &e->rule, &state)) {
1283 if (state == AUDIT_DISABLED)
1284 ret = 0;
1285 break;
1286 }
1287 }
1288 rcu_read_unlock();
1289
1290 return ret; /* Audit by default */
1291 }
1292
1293 int audit_filter_type(int type)
1294 {
1295 struct audit_entry *e;
1296 int result = 0;
1297
1298 rcu_read_lock();
1299 if (list_empty(&audit_filter_list[AUDIT_FILTER_TYPE]))
1300 goto unlock_and_return;
1301
1302 list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_TYPE],
1303 list) {
1304 int i;
1305 for (i = 0; i < e->rule.field_count; i++) {
1306 struct audit_field *f = &e->rule.fields[i];
1307 if (f->type == AUDIT_MSGTYPE) {
1308 result = audit_comparator(type, f->op, f->val);
1309 if (!result)
1310 break;
1311 }
1312 }
1313 if (result)
1314 goto unlock_and_return;
1315 }
1316 unlock_and_return:
1317 rcu_read_unlock();
1318 return result;
1319 }
1320
1321 static int update_lsm_rule(struct audit_krule *r)
1322 {
1323 struct audit_entry *entry = container_of(r, struct audit_entry, rule);
1324 struct audit_entry *nentry;
1325 struct audit_watch *watch;
1326 struct audit_tree *tree;
1327 int err = 0;
1328
1329 if (!security_audit_rule_known(r))
1330 return 0;
1331
1332 watch = r->watch;
1333 tree = r->tree;
1334 nentry = audit_dupe_rule(r, watch);
1335 if (IS_ERR(nentry)) {
1336 /* save the first error encountered for the
1337 * return value */
1338 err = PTR_ERR(nentry);
1339 audit_panic("error updating LSM filters");
1340 if (watch)
1341 list_del(&r->rlist);
1342 list_del_rcu(&entry->list);
1343 list_del(&r->list);
1344 } else {
1345 if (watch) {
1346 list_add(&nentry->rule.rlist, audit_watch_rules(watch));
1347 list_del(&r->rlist);
1348 } else if (tree)
1349 list_replace_init(&r->rlist, &nentry->rule.rlist);
1350 list_replace_rcu(&entry->list, &nentry->list);
1351 list_replace(&r->list, &nentry->rule.list);
1352 }
1353 call_rcu(&entry->rcu, audit_free_rule_rcu);
1354
1355 return err;
1356 }
1357
1358 /* This function will re-initialize the lsm_rule field of all applicable rules.
1359 * It will traverse the filter lists serarching for rules that contain LSM
1360 * specific filter fields. When such a rule is found, it is copied, the
1361 * LSM field is re-initialized, and the old rule is replaced with the
1362 * updated rule. */
1363 int audit_update_lsm_rules(void)
1364 {
1365 struct audit_krule *r, *n;
1366 int i, err = 0;
1367
1368 /* audit_filter_mutex synchronizes the writers */
1369 mutex_lock(&audit_filter_mutex);
1370
1371 for (i = 0; i < AUDIT_NR_FILTERS; i++) {
1372 list_for_each_entry_safe(r, n, &audit_rules_list[i], list) {
1373 int res = update_lsm_rule(r);
1374 if (!err)
1375 err = res;
1376 }
1377 }
1378 mutex_unlock(&audit_filter_mutex);
1379
1380 return err;
1381 }
x86 "subsystem" repository