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kselftest: Move the docs to the Documentation dir
[linux/fpc-iii.git] / kernel / auditfilter.c
blob3598e13f2a655dbbcfb0df6b6c1bd1afcebd2b8f
1 /* auditfilter.c -- filtering of audit events
2 *
3 * Copyright 2003-2004 Red Hat, Inc.
4 * Copyright 2005 Hewlett-Packard Development Company, L.P.
5 * Copyright 2005 IBM Corporation
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 */
21
22 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
23
24 #include <linux/kernel.h>
25 #include <linux/audit.h>
26 #include <linux/kthread.h>
27 #include <linux/mutex.h>
28 #include <linux/fs.h>
29 #include <linux/namei.h>
30 #include <linux/netlink.h>
31 #include <linux/sched.h>
32 #include <linux/slab.h>
33 #include <linux/security.h>
34 #include <net/net_namespace.h>
35 #include <net/sock.h>
36 #include "audit.h"
37
38 /*
39 * Locking model:
40 *
41 * audit_filter_mutex:
42 * Synchronizes writes and blocking reads of audit's filterlist
43 * data. Rcu is used to traverse the filterlist and access
44 * contents of structs audit_entry, audit_watch and opaque
45 * LSM rules during filtering. If modified, these structures
46 * must be copied and replace their counterparts in the filterlist.
47 * An audit_parent struct is not accessed during filtering, so may
48 * be written directly provided audit_filter_mutex is held.
49 */
50
51 /* Audit filter lists, defined in <linux/audit.h> */
52 struct list_head audit_filter_list[AUDIT_NR_FILTERS] = {
53 LIST_HEAD_INIT(audit_filter_list[0]),
54 LIST_HEAD_INIT(audit_filter_list[1]),
55 LIST_HEAD_INIT(audit_filter_list[2]),
56 LIST_HEAD_INIT(audit_filter_list[3]),
57 LIST_HEAD_INIT(audit_filter_list[4]),
58 LIST_HEAD_INIT(audit_filter_list[5]),
59 #if AUDIT_NR_FILTERS != 6
60 #error Fix audit_filter_list initialiser
61 #endif
62 };
63 static struct list_head audit_rules_list[AUDIT_NR_FILTERS] = {
64 LIST_HEAD_INIT(audit_rules_list[0]),
65 LIST_HEAD_INIT(audit_rules_list[1]),
66 LIST_HEAD_INIT(audit_rules_list[2]),
67 LIST_HEAD_INIT(audit_rules_list[3]),
68 LIST_HEAD_INIT(audit_rules_list[4]),
69 LIST_HEAD_INIT(audit_rules_list[5]),
70 };
71
72 DEFINE_MUTEX(audit_filter_mutex);
73
74 static void audit_free_lsm_field(struct audit_field *f)
75 {
76 switch (f->type) {
77 case AUDIT_SUBJ_USER:
78 case AUDIT_SUBJ_ROLE:
79 case AUDIT_SUBJ_TYPE:
80 case AUDIT_SUBJ_SEN:
81 case AUDIT_SUBJ_CLR:
82 case AUDIT_OBJ_USER:
83 case AUDIT_OBJ_ROLE:
84 case AUDIT_OBJ_TYPE:
85 case AUDIT_OBJ_LEV_LOW:
86 case AUDIT_OBJ_LEV_HIGH:
87 kfree(f->lsm_str);
88 security_audit_rule_free(f->lsm_rule);
89 }
90 }
91
92 static inline void audit_free_rule(struct audit_entry *e)
93 {
94 int i;
95 struct audit_krule *erule = &e->rule;
96
97 /* some rules don't have associated watches */
98 if (erule->watch)
99 audit_put_watch(erule->watch);
100 if (erule->fields)
101 for (i = 0; i < erule->field_count; i++)
102 audit_free_lsm_field(&erule->fields[i]);
103 kfree(erule->fields);
104 kfree(erule->filterkey);
105 kfree(e);
106 }
107
108 void audit_free_rule_rcu(struct rcu_head *head)
109 {
110 struct audit_entry *e = container_of(head, struct audit_entry, rcu);
111 audit_free_rule(e);
112 }
113
114 /* Initialize an audit filterlist entry. */
115 static inline struct audit_entry *audit_init_entry(u32 field_count)
116 {
117 struct audit_entry *entry;
118 struct audit_field *fields;
119
120 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
121 if (unlikely(!entry))
122 return NULL;
123
124 fields = kcalloc(field_count, sizeof(*fields), GFP_KERNEL);
125 if (unlikely(!fields)) {
126 kfree(entry);
127 return NULL;
128 }
129 entry->rule.fields = fields;
130
131 return entry;
132 }
133
134 /* Unpack a filter field's string representation from user-space
135 * buffer. */
136 char *audit_unpack_string(void **bufp, size_t *remain, size_t len)
137 {
138 char *str;
139
140 if (!*bufp || (len == 0) || (len > *remain))
141 return ERR_PTR(-EINVAL);
142
143 /* Of the currently implemented string fields, PATH_MAX
144 * defines the longest valid length.
145 */
146 if (len > PATH_MAX)
147 return ERR_PTR(-ENAMETOOLONG);
148
149 str = kmalloc(len + 1, GFP_KERNEL);
150 if (unlikely(!str))
151 return ERR_PTR(-ENOMEM);
152
153 memcpy(str, *bufp, len);
154 str[len] = 0;
155 *bufp += len;
156 *remain -= len;
157
158 return str;
159 }
160
161 /* Translate an inode field to kernel respresentation. */
162 static inline int audit_to_inode(struct audit_krule *krule,
163 struct audit_field *f)
164 {
165 if (krule->listnr != AUDIT_FILTER_EXIT ||
166 krule->inode_f || krule->watch || krule->tree ||
167 (f->op != Audit_equal && f->op != Audit_not_equal))
168 return -EINVAL;
169
170 krule->inode_f = f;
171 return 0;
172 }
173
174 static __u32 *classes[AUDIT_SYSCALL_CLASSES];
175
176 int __init audit_register_class(int class, unsigned *list)
177 {
178 __u32 *p = kcalloc(AUDIT_BITMASK_SIZE, sizeof(__u32), GFP_KERNEL);
179 if (!p)
180 return -ENOMEM;
181 while (*list != ~0U) {
182 unsigned n = *list++;
183 if (n >= AUDIT_BITMASK_SIZE * 32 - AUDIT_SYSCALL_CLASSES) {
184 kfree(p);
185 return -EINVAL;
186 }
187 p[AUDIT_WORD(n)] |= AUDIT_BIT(n);
188 }
189 if (class >= AUDIT_SYSCALL_CLASSES || classes[class]) {
190 kfree(p);
191 return -EINVAL;
192 }
193 classes[class] = p;
194 return 0;
195 }
196
197 int audit_match_class(int class, unsigned syscall)
198 {
199 if (unlikely(syscall >= AUDIT_BITMASK_SIZE * 32))
200 return 0;
201 if (unlikely(class >= AUDIT_SYSCALL_CLASSES || !classes[class]))
202 return 0;
203 return classes[class][AUDIT_WORD(syscall)] & AUDIT_BIT(syscall);
204 }
205
206 #ifdef CONFIG_AUDITSYSCALL
207 static inline int audit_match_class_bits(int class, u32 *mask)
208 {
209 int i;
210
211 if (classes[class]) {
212 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
213 if (mask[i] & classes[class][i])
214 return 0;
215 }
216 return 1;
217 }
218
219 static int audit_match_signal(struct audit_entry *entry)
220 {
221 struct audit_field *arch = entry->rule.arch_f;
222
223 if (!arch) {
224 /* When arch is unspecified, we must check both masks on biarch
225 * as syscall number alone is ambiguous. */
226 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
227 entry->rule.mask) &&
228 audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
229 entry->rule.mask));
230 }
231
232 switch(audit_classify_arch(arch->val)) {
233 case 0: /* native */
234 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
235 entry->rule.mask));
236 case 1: /* 32bit on biarch */
237 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
238 entry->rule.mask));
239 default:
240 return 1;
241 }
242 }
243 #endif
244
245 /* Common user-space to kernel rule translation. */
246 static inline struct audit_entry *audit_to_entry_common(struct audit_rule_data *rule)
247 {
248 unsigned listnr;
249 struct audit_entry *entry;
250 int i, err;
251
252 err = -EINVAL;
253 listnr = rule->flags & ~AUDIT_FILTER_PREPEND;
254 switch(listnr) {
255 default:
256 goto exit_err;
257 #ifdef CONFIG_AUDITSYSCALL
258 case AUDIT_FILTER_ENTRY:
259 if (rule->action == AUDIT_ALWAYS)
260 goto exit_err;
261 case AUDIT_FILTER_EXIT:
262 case AUDIT_FILTER_TASK:
263 #endif
264 case AUDIT_FILTER_USER:
265 case AUDIT_FILTER_TYPE:
266 ;
267 }
268 if (unlikely(rule->action == AUDIT_POSSIBLE)) {
269 pr_err("AUDIT_POSSIBLE is deprecated\n");
270 goto exit_err;
271 }
272 if (rule->action != AUDIT_NEVER && rule->action != AUDIT_ALWAYS)
273 goto exit_err;
274 if (rule->field_count > AUDIT_MAX_FIELDS)
275 goto exit_err;
276
277 err = -ENOMEM;
278 entry = audit_init_entry(rule->field_count);
279 if (!entry)
280 goto exit_err;
281
282 entry->rule.flags = rule->flags & AUDIT_FILTER_PREPEND;
283 entry->rule.listnr = listnr;
284 entry->rule.action = rule->action;
285 entry->rule.field_count = rule->field_count;
286
287 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
288 entry->rule.mask[i] = rule->mask[i];
289
290 for (i = 0; i < AUDIT_SYSCALL_CLASSES; i++) {
291 int bit = AUDIT_BITMASK_SIZE * 32 - i - 1;
292 __u32 *p = &entry->rule.mask[AUDIT_WORD(bit)];
293 __u32 *class;
294
295 if (!(*p & AUDIT_BIT(bit)))
296 continue;
297 *p &= ~AUDIT_BIT(bit);
298 class = classes[i];
299 if (class) {
300 int j;
301 for (j = 0; j < AUDIT_BITMASK_SIZE; j++)
302 entry->rule.mask[j] |= class[j];
303 }
304 }
305
306 return entry;
307
308 exit_err:
309 return ERR_PTR(err);
310 }
311
312 static u32 audit_ops[] =
313 {
314 [Audit_equal] = AUDIT_EQUAL,
315 [Audit_not_equal] = AUDIT_NOT_EQUAL,
316 [Audit_bitmask] = AUDIT_BIT_MASK,
317 [Audit_bittest] = AUDIT_BIT_TEST,
318 [Audit_lt] = AUDIT_LESS_THAN,
319 [Audit_gt] = AUDIT_GREATER_THAN,
320 [Audit_le] = AUDIT_LESS_THAN_OR_EQUAL,
321 [Audit_ge] = AUDIT_GREATER_THAN_OR_EQUAL,
322 };
323
324 static u32 audit_to_op(u32 op)
325 {
326 u32 n;
327 for (n = Audit_equal; n < Audit_bad && audit_ops[n] != op; n++)
328 ;
329 return n;
330 }
331
332 /* check if an audit field is valid */
333 static int audit_field_valid(struct audit_entry *entry, struct audit_field *f)
334 {
335 switch(f->type) {
336 case AUDIT_MSGTYPE:
337 if (entry->rule.listnr != AUDIT_FILTER_TYPE &&
338 entry->rule.listnr != AUDIT_FILTER_USER)
339 return -EINVAL;
340 break;
341 };
342
343 switch(f->type) {
344 default:
345 return -EINVAL;
346 case AUDIT_UID:
347 case AUDIT_EUID:
348 case AUDIT_SUID:
349 case AUDIT_FSUID:
350 case AUDIT_LOGINUID:
351 case AUDIT_OBJ_UID:
352 case AUDIT_GID:
353 case AUDIT_EGID:
354 case AUDIT_SGID:
355 case AUDIT_FSGID:
356 case AUDIT_OBJ_GID:
357 case AUDIT_PID:
358 case AUDIT_PERS:
359 case AUDIT_MSGTYPE:
360 case AUDIT_PPID:
361 case AUDIT_DEVMAJOR:
362 case AUDIT_DEVMINOR:
363 case AUDIT_EXIT:
364 case AUDIT_SUCCESS:
365 case AUDIT_INODE:
366 /* bit ops are only useful on syscall args */
367 if (f->op == Audit_bitmask || f->op == Audit_bittest)
368 return -EINVAL;
369 break;
370 case AUDIT_ARG0:
371 case AUDIT_ARG1:
372 case AUDIT_ARG2:
373 case AUDIT_ARG3:
374 case AUDIT_SUBJ_USER:
375 case AUDIT_SUBJ_ROLE:
376 case AUDIT_SUBJ_TYPE:
377 case AUDIT_SUBJ_SEN:
378 case AUDIT_SUBJ_CLR:
379 case AUDIT_OBJ_USER:
380 case AUDIT_OBJ_ROLE:
381 case AUDIT_OBJ_TYPE:
382 case AUDIT_OBJ_LEV_LOW:
383 case AUDIT_OBJ_LEV_HIGH:
384 case AUDIT_WATCH:
385 case AUDIT_DIR:
386 case AUDIT_FILTERKEY:
387 break;
388 case AUDIT_LOGINUID_SET:
389 if ((f->val != 0) && (f->val != 1))
390 return -EINVAL;
391 /* FALL THROUGH */
392 case AUDIT_ARCH:
393 if (f->op != Audit_not_equal && f->op != Audit_equal)
394 return -EINVAL;
395 break;
396 case AUDIT_PERM:
397 if (f->val & ~15)
398 return -EINVAL;
399 break;
400 case AUDIT_FILETYPE:
401 if (f->val & ~S_IFMT)
402 return -EINVAL;
403 break;
404 case AUDIT_FIELD_COMPARE:
405 if (f->val > AUDIT_MAX_FIELD_COMPARE)
406 return -EINVAL;
407 break;
408 };
409 return 0;
410 }
411
412 /* Translate struct audit_rule_data to kernel's rule respresentation. */
413 static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
414 size_t datasz)
415 {
416 int err = 0;
417 struct audit_entry *entry;
418 void *bufp;
419 size_t remain = datasz - sizeof(struct audit_rule_data);
420 int i;
421 char *str;
422
423 entry = audit_to_entry_common(data);
424 if (IS_ERR(entry))
425 goto exit_nofree;
426
427 bufp = data->buf;
428 entry->rule.vers_ops = 2;
429 for (i = 0; i < data->field_count; i++) {
430 struct audit_field *f = &entry->rule.fields[i];
431
432 err = -EINVAL;
433
434 f->op = audit_to_op(data->fieldflags[i]);
435 if (f->op == Audit_bad)
436 goto exit_free;
437
438 f->type = data->fields[i];
439 f->val = data->values[i];
440
441 /* Support legacy tests for a valid loginuid */
442 if ((f->type == AUDIT_LOGINUID) && (f->val == AUDIT_UID_UNSET)) {
443 f->type = AUDIT_LOGINUID_SET;
444 f->val = 0;
445 }
446
447 if ((f->type == AUDIT_PID) || (f->type == AUDIT_PPID)) {
448 struct pid *pid;
449 rcu_read_lock();
450 pid = find_vpid(f->val);
451 if (!pid) {
452 rcu_read_unlock();
453 err = -ESRCH;
454 goto exit_free;
455 }
456 f->val = pid_nr(pid);
457 rcu_read_unlock();
458 }
459
460 err = audit_field_valid(entry, f);
461 if (err)
462 goto exit_free;
463
464 err = -EINVAL;
465 switch (f->type) {
466 case AUDIT_LOGINUID:
467 case AUDIT_UID:
468 case AUDIT_EUID:
469 case AUDIT_SUID:
470 case AUDIT_FSUID:
471 case AUDIT_OBJ_UID:
472 f->uid = make_kuid(current_user_ns(), f->val);
473 if (!uid_valid(f->uid))
474 goto exit_free;
475 break;
476 case AUDIT_GID:
477 case AUDIT_EGID:
478 case AUDIT_SGID:
479 case AUDIT_FSGID:
480 case AUDIT_OBJ_GID:
481 f->gid = make_kgid(current_user_ns(), f->val);
482 if (!gid_valid(f->gid))
483 goto exit_free;
484 break;
485 case AUDIT_ARCH:
486 entry->rule.arch_f = f;
487 break;
488 case AUDIT_SUBJ_USER:
489 case AUDIT_SUBJ_ROLE:
490 case AUDIT_SUBJ_TYPE:
491 case AUDIT_SUBJ_SEN:
492 case AUDIT_SUBJ_CLR:
493 case AUDIT_OBJ_USER:
494 case AUDIT_OBJ_ROLE:
495 case AUDIT_OBJ_TYPE:
496 case AUDIT_OBJ_LEV_LOW:
497 case AUDIT_OBJ_LEV_HIGH:
498 str = audit_unpack_string(&bufp, &remain, f->val);
499 if (IS_ERR(str))
500 goto exit_free;
501 entry->rule.buflen += f->val;
502
503 err = security_audit_rule_init(f->type, f->op, str,
504 (void **)&f->lsm_rule);
505 /* Keep currently invalid fields around in case they
506 * become valid after a policy reload. */
507 if (err == -EINVAL) {
508 pr_warn("audit rule for LSM \'%s\' is invalid\n",
509 str);
510 err = 0;
511 }
512 if (err) {
513 kfree(str);
514 goto exit_free;
515 } else
516 f->lsm_str = str;
517 break;
518 case AUDIT_WATCH:
519 str = audit_unpack_string(&bufp, &remain, f->val);
520 if (IS_ERR(str))
521 goto exit_free;
522 entry->rule.buflen += f->val;
523
524 err = audit_to_watch(&entry->rule, str, f->val, f->op);
525 if (err) {
526 kfree(str);
527 goto exit_free;
528 }
529 break;
530 case AUDIT_DIR:
531 str = audit_unpack_string(&bufp, &remain, f->val);
532 if (IS_ERR(str))
533 goto exit_free;
534 entry->rule.buflen += f->val;
535
536 err = audit_make_tree(&entry->rule, str, f->op);
537 kfree(str);
538 if (err)
539 goto exit_free;
540 break;
541 case AUDIT_INODE:
542 err = audit_to_inode(&entry->rule, f);
543 if (err)
544 goto exit_free;
545 break;
546 case AUDIT_FILTERKEY:
547 if (entry->rule.filterkey || f->val > AUDIT_MAX_KEY_LEN)
548 goto exit_free;
549 str = audit_unpack_string(&bufp, &remain, f->val);
550 if (IS_ERR(str))
551 goto exit_free;
552 entry->rule.buflen += f->val;
553 entry->rule.filterkey = str;
554 break;
555 }
556 }
557
558 if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal)
559 entry->rule.inode_f = NULL;
560
561 exit_nofree:
562 return entry;
563
564 exit_free:
565 if (entry->rule.watch)
566 audit_put_watch(entry->rule.watch); /* matches initial get */
567 if (entry->rule.tree)
568 audit_put_tree(entry->rule.tree); /* that's the temporary one */
569 audit_free_rule(entry);
570 return ERR_PTR(err);
571 }
572
573 /* Pack a filter field's string representation into data block. */
574 static inline size_t audit_pack_string(void **bufp, const char *str)
575 {
576 size_t len = strlen(str);
577
578 memcpy(*bufp, str, len);
579 *bufp += len;
580
581 return len;
582 }
583
584 /* Translate kernel rule respresentation to struct audit_rule_data. */
585 static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule)
586 {
587 struct audit_rule_data *data;
588 void *bufp;
589 int i;
590
591 data = kmalloc(sizeof(*data) + krule->buflen, GFP_KERNEL);
592 if (unlikely(!data))
593 return NULL;
594 memset(data, 0, sizeof(*data));
595
596 data->flags = krule->flags | krule->listnr;
597 data->action = krule->action;
598 data->field_count = krule->field_count;
599 bufp = data->buf;
600 for (i = 0; i < data->field_count; i++) {
601 struct audit_field *f = &krule->fields[i];
602
603 data->fields[i] = f->type;
604 data->fieldflags[i] = audit_ops[f->op];
605 switch(f->type) {
606 case AUDIT_SUBJ_USER:
607 case AUDIT_SUBJ_ROLE:
608 case AUDIT_SUBJ_TYPE:
609 case AUDIT_SUBJ_SEN:
610 case AUDIT_SUBJ_CLR:
611 case AUDIT_OBJ_USER:
612 case AUDIT_OBJ_ROLE:
613 case AUDIT_OBJ_TYPE:
614 case AUDIT_OBJ_LEV_LOW:
615 case AUDIT_OBJ_LEV_HIGH:
616 data->buflen += data->values[i] =
617 audit_pack_string(&bufp, f->lsm_str);
618 break;
619 case AUDIT_WATCH:
620 data->buflen += data->values[i] =
621 audit_pack_string(&bufp,
622 audit_watch_path(krule->watch));
623 break;
624 case AUDIT_DIR:
625 data->buflen += data->values[i] =
626 audit_pack_string(&bufp,
627 audit_tree_path(krule->tree));
628 break;
629 case AUDIT_FILTERKEY:
630 data->buflen += data->values[i] =
631 audit_pack_string(&bufp, krule->filterkey);
632 break;
633 default:
634 data->values[i] = f->val;
635 }
636 }
637 for (i = 0; i < AUDIT_BITMASK_SIZE; i++) data->mask[i] = krule->mask[i];
638
639 return data;
640 }
641
642 /* Compare two rules in kernel format. Considered success if rules
643 * don't match. */
644 static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
645 {
646 int i;
647
648 if (a->flags != b->flags ||
649 a->listnr != b->listnr ||
650 a->action != b->action ||
651 a->field_count != b->field_count)
652 return 1;
653
654 for (i = 0; i < a->field_count; i++) {
655 if (a->fields[i].type != b->fields[i].type ||
656 a->fields[i].op != b->fields[i].op)
657 return 1;
658
659 switch(a->fields[i].type) {
660 case AUDIT_SUBJ_USER:
661 case AUDIT_SUBJ_ROLE:
662 case AUDIT_SUBJ_TYPE:
663 case AUDIT_SUBJ_SEN:
664 case AUDIT_SUBJ_CLR:
665 case AUDIT_OBJ_USER:
666 case AUDIT_OBJ_ROLE:
667 case AUDIT_OBJ_TYPE:
668 case AUDIT_OBJ_LEV_LOW:
669 case AUDIT_OBJ_LEV_HIGH:
670 if (strcmp(a->fields[i].lsm_str, b->fields[i].lsm_str))
671 return 1;
672 break;
673 case AUDIT_WATCH:
674 if (strcmp(audit_watch_path(a->watch),
675 audit_watch_path(b->watch)))
676 return 1;
677 break;
678 case AUDIT_DIR:
679 if (strcmp(audit_tree_path(a->tree),
680 audit_tree_path(b->tree)))
681 return 1;
682 break;
683 case AUDIT_FILTERKEY:
684 /* both filterkeys exist based on above type compare */
685 if (strcmp(a->filterkey, b->filterkey))
686 return 1;
687 break;
688 case AUDIT_UID:
689 case AUDIT_EUID:
690 case AUDIT_SUID:
691 case AUDIT_FSUID:
692 case AUDIT_LOGINUID:
693 case AUDIT_OBJ_UID:
694 if (!uid_eq(a->fields[i].uid, b->fields[i].uid))
695 return 1;
696 break;
697 case AUDIT_GID:
698 case AUDIT_EGID:
699 case AUDIT_SGID:
700 case AUDIT_FSGID:
701 case AUDIT_OBJ_GID:
702 if (!gid_eq(a->fields[i].gid, b->fields[i].gid))
703 return 1;
704 break;
705 default:
706 if (a->fields[i].val != b->fields[i].val)
707 return 1;
708 }
709 }
710
711 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
712 if (a->mask[i] != b->mask[i])
713 return 1;
714
715 return 0;
716 }
717
718 /* Duplicate LSM field information. The lsm_rule is opaque, so must be
719 * re-initialized. */
720 static inline int audit_dupe_lsm_field(struct audit_field *df,
721 struct audit_field *sf)
722 {
723 int ret = 0;
724 char *lsm_str;
725
726 /* our own copy of lsm_str */
727 lsm_str = kstrdup(sf->lsm_str, GFP_KERNEL);
728 if (unlikely(!lsm_str))
729 return -ENOMEM;
730 df->lsm_str = lsm_str;
731
732 /* our own (refreshed) copy of lsm_rule */
733 ret = security_audit_rule_init(df->type, df->op, df->lsm_str,
734 (void **)&df->lsm_rule);
735 /* Keep currently invalid fields around in case they
736 * become valid after a policy reload. */
737 if (ret == -EINVAL) {
738 pr_warn("audit rule for LSM \'%s\' is invalid\n",
739 df->lsm_str);
740 ret = 0;
741 }
742
743 return ret;
744 }
745
746 /* Duplicate an audit rule. This will be a deep copy with the exception
747 * of the watch - that pointer is carried over. The LSM specific fields
748 * will be updated in the copy. The point is to be able to replace the old
749 * rule with the new rule in the filterlist, then free the old rule.
750 * The rlist element is undefined; list manipulations are handled apart from
751 * the initial copy. */
752 struct audit_entry *audit_dupe_rule(struct audit_krule *old)
753 {
754 u32 fcount = old->field_count;
755 struct audit_entry *entry;
756 struct audit_krule *new;
757 char *fk;
758 int i, err = 0;
759
760 entry = audit_init_entry(fcount);
761 if (unlikely(!entry))
762 return ERR_PTR(-ENOMEM);
763
764 new = &entry->rule;
765 new->vers_ops = old->vers_ops;
766 new->flags = old->flags;
767 new->listnr = old->listnr;
768 new->action = old->action;
769 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
770 new->mask[i] = old->mask[i];
771 new->prio = old->prio;
772 new->buflen = old->buflen;
773 new->inode_f = old->inode_f;
774 new->field_count = old->field_count;
775
776 /*
777 * note that we are OK with not refcounting here; audit_match_tree()
778 * never dereferences tree and we can't get false positives there
779 * since we'd have to have rule gone from the list *and* removed
780 * before the chunks found by lookup had been allocated, i.e. before
781 * the beginning of list scan.
782 */
783 new->tree = old->tree;
784 memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount);
785
786 /* deep copy this information, updating the lsm_rule fields, because
787 * the originals will all be freed when the old rule is freed. */
788 for (i = 0; i < fcount; i++) {
789 switch (new->fields[i].type) {
790 case AUDIT_SUBJ_USER:
791 case AUDIT_SUBJ_ROLE:
792 case AUDIT_SUBJ_TYPE:
793 case AUDIT_SUBJ_SEN:
794 case AUDIT_SUBJ_CLR:
795 case AUDIT_OBJ_USER:
796 case AUDIT_OBJ_ROLE:
797 case AUDIT_OBJ_TYPE:
798 case AUDIT_OBJ_LEV_LOW:
799 case AUDIT_OBJ_LEV_HIGH:
800 err = audit_dupe_lsm_field(&new->fields[i],
801 &old->fields[i]);
802 break;
803 case AUDIT_FILTERKEY:
804 fk = kstrdup(old->filterkey, GFP_KERNEL);
805 if (unlikely(!fk))
806 err = -ENOMEM;
807 else
808 new->filterkey = fk;
809 }
810 if (err) {
811 audit_free_rule(entry);
812 return ERR_PTR(err);
813 }
814 }
815
816 if (old->watch) {
817 audit_get_watch(old->watch);
818 new->watch = old->watch;
819 }
820
821 return entry;
822 }
823
824 /* Find an existing audit rule.
825 * Caller must hold audit_filter_mutex to prevent stale rule data. */
826 static struct audit_entry *audit_find_rule(struct audit_entry *entry,
827 struct list_head **p)
828 {
829 struct audit_entry *e, *found = NULL;
830 struct list_head *list;
831 int h;
832
833 if (entry->rule.inode_f) {
834 h = audit_hash_ino(entry->rule.inode_f->val);
835 *p = list = &audit_inode_hash[h];
836 } else if (entry->rule.watch) {
837 /* we don't know the inode number, so must walk entire hash */
838 for (h = 0; h < AUDIT_INODE_BUCKETS; h++) {
839 list = &audit_inode_hash[h];
840 list_for_each_entry(e, list, list)
841 if (!audit_compare_rule(&entry->rule, &e->rule)) {
842 found = e;
843 goto out;
844 }
845 }
846 goto out;
847 } else {
848 *p = list = &audit_filter_list[entry->rule.listnr];
849 }
850
851 list_for_each_entry(e, list, list)
852 if (!audit_compare_rule(&entry->rule, &e->rule)) {
853 found = e;
854 goto out;
855 }
856
857 out:
858 return found;
859 }
860
861 static u64 prio_low = ~0ULL/2;
862 static u64 prio_high = ~0ULL/2 - 1;
863
864 /* Add rule to given filterlist if not a duplicate. */
865 static inline int audit_add_rule(struct audit_entry *entry)
866 {
867 struct audit_entry *e;
868 struct audit_watch *watch = entry->rule.watch;
869 struct audit_tree *tree = entry->rule.tree;
870 struct list_head *list;
871 int err;
872 #ifdef CONFIG_AUDITSYSCALL
873 int dont_count = 0;
874
875 /* If either of these, don't count towards total */
876 if (entry->rule.listnr == AUDIT_FILTER_USER ||
877 entry->rule.listnr == AUDIT_FILTER_TYPE)
878 dont_count = 1;
879 #endif
880
881 mutex_lock(&audit_filter_mutex);
882 e = audit_find_rule(entry, &list);
883 if (e) {
884 mutex_unlock(&audit_filter_mutex);
885 err = -EEXIST;
886 /* normally audit_add_tree_rule() will free it on failure */
887 if (tree)
888 audit_put_tree(tree);
889 goto error;
890 }
891
892 if (watch) {
893 /* audit_filter_mutex is dropped and re-taken during this call */
894 err = audit_add_watch(&entry->rule, &list);
895 if (err) {
896 mutex_unlock(&audit_filter_mutex);
897 /*
898 * normally audit_add_tree_rule() will free it
899 * on failure
900 */
901 if (tree)
902 audit_put_tree(tree);
903 goto error;
904 }
905 }
906 if (tree) {
907 err = audit_add_tree_rule(&entry->rule);
908 if (err) {
909 mutex_unlock(&audit_filter_mutex);
910 goto error;
911 }
912 }
913
914 entry->rule.prio = ~0ULL;
915 if (entry->rule.listnr == AUDIT_FILTER_EXIT) {
916 if (entry->rule.flags & AUDIT_FILTER_PREPEND)
917 entry->rule.prio = ++prio_high;
918 else
919 entry->rule.prio = --prio_low;
920 }
921
922 if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
923 list_add(&entry->rule.list,
924 &audit_rules_list[entry->rule.listnr]);
925 list_add_rcu(&entry->list, list);
926 entry->rule.flags &= ~AUDIT_FILTER_PREPEND;
927 } else {
928 list_add_tail(&entry->rule.list,
929 &audit_rules_list[entry->rule.listnr]);
930 list_add_tail_rcu(&entry->list, list);
931 }
932 #ifdef CONFIG_AUDITSYSCALL
933 if (!dont_count)
934 audit_n_rules++;
935
936 if (!audit_match_signal(entry))
937 audit_signals++;
938 #endif
939 mutex_unlock(&audit_filter_mutex);
940
941 return 0;
942
943 error:
944 if (watch)
945 audit_put_watch(watch); /* tmp watch, matches initial get */
946 return err;
947 }
948
949 /* Remove an existing rule from filterlist. */
950 static inline int audit_del_rule(struct audit_entry *entry)
951 {
952 struct audit_entry *e;
953 struct audit_watch *watch = entry->rule.watch;
954 struct audit_tree *tree = entry->rule.tree;
955 struct list_head *list;
956 int ret = 0;
957 #ifdef CONFIG_AUDITSYSCALL
958 int dont_count = 0;
959
960 /* If either of these, don't count towards total */
961 if (entry->rule.listnr == AUDIT_FILTER_USER ||
962 entry->rule.listnr == AUDIT_FILTER_TYPE)
963 dont_count = 1;
964 #endif
965
966 mutex_lock(&audit_filter_mutex);
967 e = audit_find_rule(entry, &list);
968 if (!e) {
969 mutex_unlock(&audit_filter_mutex);
970 ret = -ENOENT;
971 goto out;
972 }
973
974 if (e->rule.watch)
975 audit_remove_watch_rule(&e->rule);
976
977 if (e->rule.tree)
978 audit_remove_tree_rule(&e->rule);
979
980 list_del_rcu(&e->list);
981 list_del(&e->rule.list);
982 call_rcu(&e->rcu, audit_free_rule_rcu);
983
984 #ifdef CONFIG_AUDITSYSCALL
985 if (!dont_count)
986 audit_n_rules--;
987
988 if (!audit_match_signal(entry))
989 audit_signals--;
990 #endif
991 mutex_unlock(&audit_filter_mutex);
992
993 out:
994 if (watch)
995 audit_put_watch(watch); /* match initial get */
996 if (tree)
997 audit_put_tree(tree); /* that's the temporary one */
998
999 return ret;
1000 }
1001
1002 /* List rules using struct audit_rule_data. */
1003 static void audit_list_rules(__u32 portid, 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_data *data;
1014
1015 data = audit_krule_to_data(r);
1016 if (unlikely(!data))
1017 break;
1018 skb = audit_make_reply(portid, seq, AUDIT_LIST_RULES,
1019 0, 1, data,
1020 sizeof(*data) + data->buflen);
1021 if (skb)
1022 skb_queue_tail(q, skb);
1023 kfree(data);
1024 }
1025 }
1026 skb = audit_make_reply(portid, seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);
1027 if (skb)
1028 skb_queue_tail(q, skb);
1029 }
1030
1031 /* Log rule additions and removals */
1032 static void audit_log_rule_change(char *action, struct audit_krule *rule, int res)
1033 {
1034 struct audit_buffer *ab;
1035 uid_t loginuid = from_kuid(&init_user_ns, audit_get_loginuid(current));
1036 unsigned int sessionid = audit_get_sessionid(current);
1037
1038 if (!audit_enabled)
1039 return;
1040
1041 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
1042 if (!ab)
1043 return;
1044 audit_log_format(ab, "auid=%u ses=%u" ,loginuid, sessionid);
1045 audit_log_task_context(ab);
1046 audit_log_format(ab, " op=");
1047 audit_log_string(ab, action);
1048 audit_log_key(ab, rule->filterkey);
1049 audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
1050 audit_log_end(ab);
1051 }
1052
1053 /**
1054 * audit_rule_change - apply all rules to the specified message type
1055 * @type: audit message type
1056 * @portid: target port id for netlink audit messages
1057 * @seq: netlink audit message sequence (serial) number
1058 * @data: payload data
1059 * @datasz: size of payload data
1060 */
1061 int audit_rule_change(int type, __u32 portid, int seq, void *data,
1062 size_t datasz)
1063 {
1064 int err = 0;
1065 struct audit_entry *entry;
1066
1067 entry = audit_data_to_entry(data, datasz);
1068 if (IS_ERR(entry))
1069 return PTR_ERR(entry);
1070
1071 switch (type) {
1072 case AUDIT_ADD_RULE:
1073 err = audit_add_rule(entry);
1074 audit_log_rule_change("add_rule", &entry->rule, !err);
1075 break;
1076 case AUDIT_DEL_RULE:
1077 err = audit_del_rule(entry);
1078 audit_log_rule_change("remove_rule", &entry->rule, !err);
1079 break;
1080 default:
1081 err = -EINVAL;
1082 WARN_ON(1);
1083 }
1084
1085 if (err || type == AUDIT_DEL_RULE)
1086 audit_free_rule(entry);
1087
1088 return err;
1089 }
1090
1091 /**
1092 * audit_list_rules_send - list the audit rules
1093 * @request_skb: skb of request we are replying to (used to target the reply)
1094 * @seq: netlink audit message sequence (serial) number
1095 */
1096 int audit_list_rules_send(struct sk_buff *request_skb, int seq)
1097 {
1098 u32 portid = NETLINK_CB(request_skb).portid;
1099 struct net *net = sock_net(NETLINK_CB(request_skb).sk);
1100 struct task_struct *tsk;
1101 struct audit_netlink_list *dest;
1102 int err = 0;
1103
1104 /* We can't just spew out the rules here because we might fill
1105 * the available socket buffer space and deadlock waiting for
1106 * auditctl to read from it... which isn't ever going to
1107 * happen if we're actually running in the context of auditctl
1108 * trying to _send_ the stuff */
1109
1110 dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL);
1111 if (!dest)
1112 return -ENOMEM;
1113 dest->net = get_net(net);
1114 dest->portid = portid;
1115 skb_queue_head_init(&dest->q);
1116
1117 mutex_lock(&audit_filter_mutex);
1118 audit_list_rules(portid, seq, &dest->q);
1119 mutex_unlock(&audit_filter_mutex);
1120
1121 tsk = kthread_run(audit_send_list, dest, "audit_send_list");
1122 if (IS_ERR(tsk)) {
1123 skb_queue_purge(&dest->q);
1124 kfree(dest);
1125 err = PTR_ERR(tsk);
1126 }
1127
1128 return err;
1129 }
1130
1131 int audit_comparator(u32 left, u32 op, u32 right)
1132 {
1133 switch (op) {
1134 case Audit_equal:
1135 return (left == right);
1136 case Audit_not_equal:
1137 return (left != right);
1138 case Audit_lt:
1139 return (left < right);
1140 case Audit_le:
1141 return (left <= right);
1142 case Audit_gt:
1143 return (left > right);
1144 case Audit_ge:
1145 return (left >= right);
1146 case Audit_bitmask:
1147 return (left & right);
1148 case Audit_bittest:
1149 return ((left & right) == right);
1150 default:
1151 BUG();
1152 return 0;
1153 }
1154 }
1155
1156 int audit_uid_comparator(kuid_t left, u32 op, kuid_t right)
1157 {
1158 switch (op) {
1159 case Audit_equal:
1160 return uid_eq(left, right);
1161 case Audit_not_equal:
1162 return !uid_eq(left, right);
1163 case Audit_lt:
1164 return uid_lt(left, right);
1165 case Audit_le:
1166 return uid_lte(left, right);
1167 case Audit_gt:
1168 return uid_gt(left, right);
1169 case Audit_ge:
1170 return uid_gte(left, right);
1171 case Audit_bitmask:
1172 case Audit_bittest:
1173 default:
1174 BUG();
1175 return 0;
1176 }
1177 }
1178
1179 int audit_gid_comparator(kgid_t left, u32 op, kgid_t right)
1180 {
1181 switch (op) {
1182 case Audit_equal:
1183 return gid_eq(left, right);
1184 case Audit_not_equal:
1185 return !gid_eq(left, right);
1186 case Audit_lt:
1187 return gid_lt(left, right);
1188 case Audit_le:
1189 return gid_lte(left, right);
1190 case Audit_gt:
1191 return gid_gt(left, right);
1192 case Audit_ge:
1193 return gid_gte(left, right);
1194 case Audit_bitmask:
1195 case Audit_bittest:
1196 default:
1197 BUG();
1198 return 0;
1199 }
1200 }
1201
1202 /**
1203 * parent_len - find the length of the parent portion of a pathname
1204 * @path: pathname of which to determine length
1205 */
1206 int parent_len(const char *path)
1207 {
1208 int plen;
1209 const char *p;
1210
1211 plen = strlen(path);
1212
1213 if (plen == 0)
1214 return plen;
1215
1216 /* disregard trailing slashes */
1217 p = path + plen - 1;
1218 while ((*p == '/') && (p > path))
1219 p--;
1220
1221 /* walk backward until we find the next slash or hit beginning */
1222 while ((*p != '/') && (p > path))
1223 p--;
1224
1225 /* did we find a slash? Then increment to include it in path */
1226 if (*p == '/')
1227 p++;
1228
1229 return p - path;
1230 }
1231
1232 /**
1233 * audit_compare_dname_path - compare given dentry name with last component in
1234 * given path. Return of 0 indicates a match.
1235 * @dname: dentry name that we're comparing
1236 * @path: full pathname that we're comparing
1237 * @parentlen: length of the parent if known. Passing in AUDIT_NAME_FULL
1238 * here indicates that we must compute this value.
1239 */
1240 int audit_compare_dname_path(const char *dname, const char *path, int parentlen)
1241 {
1242 int dlen, pathlen;
1243 const char *p;
1244
1245 dlen = strlen(dname);
1246 pathlen = strlen(path);
1247 if (pathlen < dlen)
1248 return 1;
1249
1250 parentlen = parentlen == AUDIT_NAME_FULL ? parent_len(path) : parentlen;
1251 if (pathlen - parentlen != dlen)
1252 return 1;
1253
1254 p = path + parentlen;
1255
1256 return strncmp(p, dname, dlen);
1257 }
1258
1259 static int audit_filter_user_rules(struct audit_krule *rule, int type,
1260 enum audit_state *state)
1261 {
1262 int i;
1263
1264 for (i = 0; i < rule->field_count; i++) {
1265 struct audit_field *f = &rule->fields[i];
1266 pid_t pid;
1267 int result = 0;
1268 u32 sid;
1269
1270 switch (f->type) {
1271 case AUDIT_PID:
1272 pid = task_pid_nr(current);
1273 result = audit_comparator(pid, f->op, f->val);
1274 break;
1275 case AUDIT_UID:
1276 result = audit_uid_comparator(current_uid(), f->op, f->uid);
1277 break;
1278 case AUDIT_GID:
1279 result = audit_gid_comparator(current_gid(), f->op, f->gid);
1280 break;
1281 case AUDIT_LOGINUID:
1282 result = audit_uid_comparator(audit_get_loginuid(current),
1283 f->op, f->uid);
1284 break;
1285 case AUDIT_LOGINUID_SET:
1286 result = audit_comparator(audit_loginuid_set(current),
1287 f->op, f->val);
1288 break;
1289 case AUDIT_MSGTYPE:
1290 result = audit_comparator(type, f->op, f->val);
1291 break;
1292 case AUDIT_SUBJ_USER:
1293 case AUDIT_SUBJ_ROLE:
1294 case AUDIT_SUBJ_TYPE:
1295 case AUDIT_SUBJ_SEN:
1296 case AUDIT_SUBJ_CLR:
1297 if (f->lsm_rule) {
1298 security_task_getsecid(current, &sid);
1299 result = security_audit_rule_match(sid,
1300 f->type,
1301 f->op,
1302 f->lsm_rule,
1303 NULL);
1304 }
1305 break;
1306 }
1307
1308 if (!result)
1309 return 0;
1310 }
1311 switch (rule->action) {
1312 case AUDIT_NEVER: *state = AUDIT_DISABLED; break;
1313 case AUDIT_ALWAYS: *state = AUDIT_RECORD_CONTEXT; break;
1314 }
1315 return 1;
1316 }
1317
1318 int audit_filter_user(int type)
1319 {
1320 enum audit_state state = AUDIT_DISABLED;
1321 struct audit_entry *e;
1322 int rc, ret;
1323
1324 ret = 1; /* Audit by default */
1325
1326 rcu_read_lock();
1327 list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_USER], list) {
1328 rc = audit_filter_user_rules(&e->rule, type, &state);
1329 if (rc) {
1330 if (rc > 0 && state == AUDIT_DISABLED)
1331 ret = 0;
1332 break;
1333 }
1334 }
1335 rcu_read_unlock();
1336
1337 return ret;
1338 }
1339
1340 int audit_filter_type(int type)
1341 {
1342 struct audit_entry *e;
1343 int result = 0;
1344
1345 rcu_read_lock();
1346 if (list_empty(&audit_filter_list[AUDIT_FILTER_TYPE]))
1347 goto unlock_and_return;
1348
1349 list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_TYPE],
1350 list) {
1351 int i;
1352 for (i = 0; i < e->rule.field_count; i++) {
1353 struct audit_field *f = &e->rule.fields[i];
1354 if (f->type == AUDIT_MSGTYPE) {
1355 result = audit_comparator(type, f->op, f->val);
1356 if (!result)
1357 break;
1358 }
1359 }
1360 if (result)
1361 goto unlock_and_return;
1362 }
1363 unlock_and_return:
1364 rcu_read_unlock();
1365 return result;
1366 }
1367
1368 static int update_lsm_rule(struct audit_krule *r)
1369 {
1370 struct audit_entry *entry = container_of(r, struct audit_entry, rule);
1371 struct audit_entry *nentry;
1372 int err = 0;
1373
1374 if (!security_audit_rule_known(r))
1375 return 0;
1376
1377 nentry = audit_dupe_rule(r);
1378 if (IS_ERR(nentry)) {
1379 /* save the first error encountered for the
1380 * return value */
1381 err = PTR_ERR(nentry);
1382 audit_panic("error updating LSM filters");
1383 if (r->watch)
1384 list_del(&r->rlist);
1385 list_del_rcu(&entry->list);
1386 list_del(&r->list);
1387 } else {
1388 if (r->watch || r->tree)
1389 list_replace_init(&r->rlist, &nentry->rule.rlist);
1390 list_replace_rcu(&entry->list, &nentry->list);
1391 list_replace(&r->list, &nentry->rule.list);
1392 }
1393 call_rcu(&entry->rcu, audit_free_rule_rcu);
1394
1395 return err;
1396 }
1397
1398 /* This function will re-initialize the lsm_rule field of all applicable rules.
1399 * It will traverse the filter lists serarching for rules that contain LSM
1400 * specific filter fields. When such a rule is found, it is copied, the
1401 * LSM field is re-initialized, and the old rule is replaced with the
1402 * updated rule. */
1403 int audit_update_lsm_rules(void)
1404 {
1405 struct audit_krule *r, *n;
1406 int i, err = 0;
1407
1408 /* audit_filter_mutex synchronizes the writers */
1409 mutex_lock(&audit_filter_mutex);
1410
1411 for (i = 0; i < AUDIT_NR_FILTERS; i++) {
1412 list_for_each_entry_safe(r, n, &audit_rules_list[i], list) {
1413 int res = update_lsm_rule(r);
1414 if (!err)
1415 err = res;
1416 }
1417 }
1418 mutex_unlock(&audit_filter_mutex);
1419
1420 return err;
1421 }
Linux with added FPC-III support