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Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus
[linux-2.6.git] / kernel / auditfilter.c
blobf7aee8be7fb286db4a40919bc10ede18f17016dc
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 == ~0U)) {
427 f->type = AUDIT_LOGINUID_SET;
428 f->val = 0;
429 }
430
431 err = audit_field_valid(entry, f);
432 if (err)
433 goto exit_free;
434
435 err = -EINVAL;
436 switch (f->type) {
437 case AUDIT_LOGINUID:
438 case AUDIT_UID:
439 case AUDIT_EUID:
440 case AUDIT_SUID:
441 case AUDIT_FSUID:
442 case AUDIT_OBJ_UID:
443 f->uid = make_kuid(current_user_ns(), f->val);
444 if (!uid_valid(f->uid))
445 goto exit_free;
446 break;
447 case AUDIT_GID:
448 case AUDIT_EGID:
449 case AUDIT_SGID:
450 case AUDIT_FSGID:
451 case AUDIT_OBJ_GID:
452 f->gid = make_kgid(current_user_ns(), f->val);
453 if (!gid_valid(f->gid))
454 goto exit_free;
455 break;
456 case AUDIT_ARCH:
457 entry->rule.arch_f = f;
458 break;
459 case AUDIT_SUBJ_USER:
460 case AUDIT_SUBJ_ROLE:
461 case AUDIT_SUBJ_TYPE:
462 case AUDIT_SUBJ_SEN:
463 case AUDIT_SUBJ_CLR:
464 case AUDIT_OBJ_USER:
465 case AUDIT_OBJ_ROLE:
466 case AUDIT_OBJ_TYPE:
467 case AUDIT_OBJ_LEV_LOW:
468 case AUDIT_OBJ_LEV_HIGH:
469 str = audit_unpack_string(&bufp, &remain, f->val);
470 if (IS_ERR(str))
471 goto exit_free;
472 entry->rule.buflen += f->val;
473
474 err = security_audit_rule_init(f->type, f->op, str,
475 (void **)&f->lsm_rule);
476 /* Keep currently invalid fields around in case they
477 * become valid after a policy reload. */
478 if (err == -EINVAL) {
479 printk(KERN_WARNING "audit rule for LSM "
480 "\'%s\' is invalid\n", str);
481 err = 0;
482 }
483 if (err) {
484 kfree(str);
485 goto exit_free;
486 } else
487 f->lsm_str = str;
488 break;
489 case AUDIT_WATCH:
490 str = audit_unpack_string(&bufp, &remain, f->val);
491 if (IS_ERR(str))
492 goto exit_free;
493 entry->rule.buflen += f->val;
494
495 err = audit_to_watch(&entry->rule, str, f->val, f->op);
496 if (err) {
497 kfree(str);
498 goto exit_free;
499 }
500 break;
501 case AUDIT_DIR:
502 str = audit_unpack_string(&bufp, &remain, f->val);
503 if (IS_ERR(str))
504 goto exit_free;
505 entry->rule.buflen += f->val;
506
507 err = audit_make_tree(&entry->rule, str, f->op);
508 kfree(str);
509 if (err)
510 goto exit_free;
511 break;
512 case AUDIT_INODE:
513 err = audit_to_inode(&entry->rule, f);
514 if (err)
515 goto exit_free;
516 break;
517 case AUDIT_FILTERKEY:
518 if (entry->rule.filterkey || f->val > AUDIT_MAX_KEY_LEN)
519 goto exit_free;
520 str = audit_unpack_string(&bufp, &remain, f->val);
521 if (IS_ERR(str))
522 goto exit_free;
523 entry->rule.buflen += f->val;
524 entry->rule.filterkey = str;
525 break;
526 }
527 }
528
529 if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal)
530 entry->rule.inode_f = NULL;
531
532 exit_nofree:
533 return entry;
534
535 exit_free:
536 if (entry->rule.watch)
537 audit_put_watch(entry->rule.watch); /* matches initial get */
538 if (entry->rule.tree)
539 audit_put_tree(entry->rule.tree); /* that's the temporary one */
540 audit_free_rule(entry);
541 return ERR_PTR(err);
542 }
543
544 /* Pack a filter field's string representation into data block. */
545 static inline size_t audit_pack_string(void **bufp, const char *str)
546 {
547 size_t len = strlen(str);
548
549 memcpy(*bufp, str, len);
550 *bufp += len;
551
552 return len;
553 }
554
555 /* Translate kernel rule respresentation to struct audit_rule_data. */
556 static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule)
557 {
558 struct audit_rule_data *data;
559 void *bufp;
560 int i;
561
562 data = kmalloc(sizeof(*data) + krule->buflen, GFP_KERNEL);
563 if (unlikely(!data))
564 return NULL;
565 memset(data, 0, sizeof(*data));
566
567 data->flags = krule->flags | krule->listnr;
568 data->action = krule->action;
569 data->field_count = krule->field_count;
570 bufp = data->buf;
571 for (i = 0; i < data->field_count; i++) {
572 struct audit_field *f = &krule->fields[i];
573
574 data->fields[i] = f->type;
575 data->fieldflags[i] = audit_ops[f->op];
576 switch(f->type) {
577 case AUDIT_SUBJ_USER:
578 case AUDIT_SUBJ_ROLE:
579 case AUDIT_SUBJ_TYPE:
580 case AUDIT_SUBJ_SEN:
581 case AUDIT_SUBJ_CLR:
582 case AUDIT_OBJ_USER:
583 case AUDIT_OBJ_ROLE:
584 case AUDIT_OBJ_TYPE:
585 case AUDIT_OBJ_LEV_LOW:
586 case AUDIT_OBJ_LEV_HIGH:
587 data->buflen += data->values[i] =
588 audit_pack_string(&bufp, f->lsm_str);
589 break;
590 case AUDIT_WATCH:
591 data->buflen += data->values[i] =
592 audit_pack_string(&bufp,
593 audit_watch_path(krule->watch));
594 break;
595 case AUDIT_DIR:
596 data->buflen += data->values[i] =
597 audit_pack_string(&bufp,
598 audit_tree_path(krule->tree));
599 break;
600 case AUDIT_FILTERKEY:
601 data->buflen += data->values[i] =
602 audit_pack_string(&bufp, krule->filterkey);
603 break;
604 default:
605 data->values[i] = f->val;
606 }
607 }
608 for (i = 0; i < AUDIT_BITMASK_SIZE; i++) data->mask[i] = krule->mask[i];
609
610 return data;
611 }
612
613 /* Compare two rules in kernel format. Considered success if rules
614 * don't match. */
615 static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
616 {
617 int i;
618
619 if (a->flags != b->flags ||
620 a->listnr != b->listnr ||
621 a->action != b->action ||
622 a->field_count != b->field_count)
623 return 1;
624
625 for (i = 0; i < a->field_count; i++) {
626 if (a->fields[i].type != b->fields[i].type ||
627 a->fields[i].op != b->fields[i].op)
628 return 1;
629
630 switch(a->fields[i].type) {
631 case AUDIT_SUBJ_USER:
632 case AUDIT_SUBJ_ROLE:
633 case AUDIT_SUBJ_TYPE:
634 case AUDIT_SUBJ_SEN:
635 case AUDIT_SUBJ_CLR:
636 case AUDIT_OBJ_USER:
637 case AUDIT_OBJ_ROLE:
638 case AUDIT_OBJ_TYPE:
639 case AUDIT_OBJ_LEV_LOW:
640 case AUDIT_OBJ_LEV_HIGH:
641 if (strcmp(a->fields[i].lsm_str, b->fields[i].lsm_str))
642 return 1;
643 break;
644 case AUDIT_WATCH:
645 if (strcmp(audit_watch_path(a->watch),
646 audit_watch_path(b->watch)))
647 return 1;
648 break;
649 case AUDIT_DIR:
650 if (strcmp(audit_tree_path(a->tree),
651 audit_tree_path(b->tree)))
652 return 1;
653 break;
654 case AUDIT_FILTERKEY:
655 /* both filterkeys exist based on above type compare */
656 if (strcmp(a->filterkey, b->filterkey))
657 return 1;
658 break;
659 case AUDIT_UID:
660 case AUDIT_EUID:
661 case AUDIT_SUID:
662 case AUDIT_FSUID:
663 case AUDIT_LOGINUID:
664 case AUDIT_OBJ_UID:
665 if (!uid_eq(a->fields[i].uid, b->fields[i].uid))
666 return 1;
667 break;
668 case AUDIT_GID:
669 case AUDIT_EGID:
670 case AUDIT_SGID:
671 case AUDIT_FSGID:
672 case AUDIT_OBJ_GID:
673 if (!gid_eq(a->fields[i].gid, b->fields[i].gid))
674 return 1;
675 break;
676 default:
677 if (a->fields[i].val != b->fields[i].val)
678 return 1;
679 }
680 }
681
682 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
683 if (a->mask[i] != b->mask[i])
684 return 1;
685
686 return 0;
687 }
688
689 /* Duplicate LSM field information. The lsm_rule is opaque, so must be
690 * re-initialized. */
691 static inline int audit_dupe_lsm_field(struct audit_field *df,
692 struct audit_field *sf)
693 {
694 int ret = 0;
695 char *lsm_str;
696
697 /* our own copy of lsm_str */
698 lsm_str = kstrdup(sf->lsm_str, GFP_KERNEL);
699 if (unlikely(!lsm_str))
700 return -ENOMEM;
701 df->lsm_str = lsm_str;
702
703 /* our own (refreshed) copy of lsm_rule */
704 ret = security_audit_rule_init(df->type, df->op, df->lsm_str,
705 (void **)&df->lsm_rule);
706 /* Keep currently invalid fields around in case they
707 * become valid after a policy reload. */
708 if (ret == -EINVAL) {
709 printk(KERN_WARNING "audit rule for LSM \'%s\' is "
710 "invalid\n", df->lsm_str);
711 ret = 0;
712 }
713
714 return ret;
715 }
716
717 /* Duplicate an audit rule. This will be a deep copy with the exception
718 * of the watch - that pointer is carried over. The LSM specific fields
719 * will be updated in the copy. The point is to be able to replace the old
720 * rule with the new rule in the filterlist, then free the old rule.
721 * The rlist element is undefined; list manipulations are handled apart from
722 * the initial copy. */
723 struct audit_entry *audit_dupe_rule(struct audit_krule *old)
724 {
725 u32 fcount = old->field_count;
726 struct audit_entry *entry;
727 struct audit_krule *new;
728 char *fk;
729 int i, err = 0;
730
731 entry = audit_init_entry(fcount);
732 if (unlikely(!entry))
733 return ERR_PTR(-ENOMEM);
734
735 new = &entry->rule;
736 new->vers_ops = old->vers_ops;
737 new->flags = old->flags;
738 new->listnr = old->listnr;
739 new->action = old->action;
740 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
741 new->mask[i] = old->mask[i];
742 new->prio = old->prio;
743 new->buflen = old->buflen;
744 new->inode_f = old->inode_f;
745 new->field_count = old->field_count;
746
747 /*
748 * note that we are OK with not refcounting here; audit_match_tree()
749 * never dereferences tree and we can't get false positives there
750 * since we'd have to have rule gone from the list *and* removed
751 * before the chunks found by lookup had been allocated, i.e. before
752 * the beginning of list scan.
753 */
754 new->tree = old->tree;
755 memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount);
756
757 /* deep copy this information, updating the lsm_rule fields, because
758 * the originals will all be freed when the old rule is freed. */
759 for (i = 0; i < fcount; i++) {
760 switch (new->fields[i].type) {
761 case AUDIT_SUBJ_USER:
762 case AUDIT_SUBJ_ROLE:
763 case AUDIT_SUBJ_TYPE:
764 case AUDIT_SUBJ_SEN:
765 case AUDIT_SUBJ_CLR:
766 case AUDIT_OBJ_USER:
767 case AUDIT_OBJ_ROLE:
768 case AUDIT_OBJ_TYPE:
769 case AUDIT_OBJ_LEV_LOW:
770 case AUDIT_OBJ_LEV_HIGH:
771 err = audit_dupe_lsm_field(&new->fields[i],
772 &old->fields[i]);
773 break;
774 case AUDIT_FILTERKEY:
775 fk = kstrdup(old->filterkey, GFP_KERNEL);
776 if (unlikely(!fk))
777 err = -ENOMEM;
778 else
779 new->filterkey = fk;
780 }
781 if (err) {
782 audit_free_rule(entry);
783 return ERR_PTR(err);
784 }
785 }
786
787 if (old->watch) {
788 audit_get_watch(old->watch);
789 new->watch = old->watch;
790 }
791
792 return entry;
793 }
794
795 /* Find an existing audit rule.
796 * Caller must hold audit_filter_mutex to prevent stale rule data. */
797 static struct audit_entry *audit_find_rule(struct audit_entry *entry,
798 struct list_head **p)
799 {
800 struct audit_entry *e, *found = NULL;
801 struct list_head *list;
802 int h;
803
804 if (entry->rule.inode_f) {
805 h = audit_hash_ino(entry->rule.inode_f->val);
806 *p = list = &audit_inode_hash[h];
807 } else if (entry->rule.watch) {
808 /* we don't know the inode number, so must walk entire hash */
809 for (h = 0; h < AUDIT_INODE_BUCKETS; h++) {
810 list = &audit_inode_hash[h];
811 list_for_each_entry(e, list, list)
812 if (!audit_compare_rule(&entry->rule, &e->rule)) {
813 found = e;
814 goto out;
815 }
816 }
817 goto out;
818 } else {
819 *p = list = &audit_filter_list[entry->rule.listnr];
820 }
821
822 list_for_each_entry(e, list, list)
823 if (!audit_compare_rule(&entry->rule, &e->rule)) {
824 found = e;
825 goto out;
826 }
827
828 out:
829 return found;
830 }
831
832 static u64 prio_low = ~0ULL/2;
833 static u64 prio_high = ~0ULL/2 - 1;
834
835 /* Add rule to given filterlist if not a duplicate. */
836 static inline int audit_add_rule(struct audit_entry *entry)
837 {
838 struct audit_entry *e;
839 struct audit_watch *watch = entry->rule.watch;
840 struct audit_tree *tree = entry->rule.tree;
841 struct list_head *list;
842 int err;
843 #ifdef CONFIG_AUDITSYSCALL
844 int dont_count = 0;
845
846 /* If either of these, don't count towards total */
847 if (entry->rule.listnr == AUDIT_FILTER_USER ||
848 entry->rule.listnr == AUDIT_FILTER_TYPE)
849 dont_count = 1;
850 #endif
851
852 mutex_lock(&audit_filter_mutex);
853 e = audit_find_rule(entry, &list);
854 if (e) {
855 mutex_unlock(&audit_filter_mutex);
856 err = -EEXIST;
857 /* normally audit_add_tree_rule() will free it on failure */
858 if (tree)
859 audit_put_tree(tree);
860 goto error;
861 }
862
863 if (watch) {
864 /* audit_filter_mutex is dropped and re-taken during this call */
865 err = audit_add_watch(&entry->rule, &list);
866 if (err) {
867 mutex_unlock(&audit_filter_mutex);
868 /*
869 * normally audit_add_tree_rule() will free it
870 * on failure
871 */
872 if (tree)
873 audit_put_tree(tree);
874 goto error;
875 }
876 }
877 if (tree) {
878 err = audit_add_tree_rule(&entry->rule);
879 if (err) {
880 mutex_unlock(&audit_filter_mutex);
881 goto error;
882 }
883 }
884
885 entry->rule.prio = ~0ULL;
886 if (entry->rule.listnr == AUDIT_FILTER_EXIT) {
887 if (entry->rule.flags & AUDIT_FILTER_PREPEND)
888 entry->rule.prio = ++prio_high;
889 else
890 entry->rule.prio = --prio_low;
891 }
892
893 if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
894 list_add(&entry->rule.list,
895 &audit_rules_list[entry->rule.listnr]);
896 list_add_rcu(&entry->list, list);
897 entry->rule.flags &= ~AUDIT_FILTER_PREPEND;
898 } else {
899 list_add_tail(&entry->rule.list,
900 &audit_rules_list[entry->rule.listnr]);
901 list_add_tail_rcu(&entry->list, list);
902 }
903 #ifdef CONFIG_AUDITSYSCALL
904 if (!dont_count)
905 audit_n_rules++;
906
907 if (!audit_match_signal(entry))
908 audit_signals++;
909 #endif
910 mutex_unlock(&audit_filter_mutex);
911
912 return 0;
913
914 error:
915 if (watch)
916 audit_put_watch(watch); /* tmp watch, matches initial get */
917 return err;
918 }
919
920 /* Remove an existing rule from filterlist. */
921 static inline int audit_del_rule(struct audit_entry *entry)
922 {
923 struct audit_entry *e;
924 struct audit_watch *watch = entry->rule.watch;
925 struct audit_tree *tree = entry->rule.tree;
926 struct list_head *list;
927 int ret = 0;
928 #ifdef CONFIG_AUDITSYSCALL
929 int dont_count = 0;
930
931 /* If either of these, don't count towards total */
932 if (entry->rule.listnr == AUDIT_FILTER_USER ||
933 entry->rule.listnr == AUDIT_FILTER_TYPE)
934 dont_count = 1;
935 #endif
936
937 mutex_lock(&audit_filter_mutex);
938 e = audit_find_rule(entry, &list);
939 if (!e) {
940 mutex_unlock(&audit_filter_mutex);
941 ret = -ENOENT;
942 goto out;
943 }
944
945 if (e->rule.watch)
946 audit_remove_watch_rule(&e->rule);
947
948 if (e->rule.tree)
949 audit_remove_tree_rule(&e->rule);
950
951 list_del_rcu(&e->list);
952 list_del(&e->rule.list);
953 call_rcu(&e->rcu, audit_free_rule_rcu);
954
955 #ifdef CONFIG_AUDITSYSCALL
956 if (!dont_count)
957 audit_n_rules--;
958
959 if (!audit_match_signal(entry))
960 audit_signals--;
961 #endif
962 mutex_unlock(&audit_filter_mutex);
963
964 out:
965 if (watch)
966 audit_put_watch(watch); /* match initial get */
967 if (tree)
968 audit_put_tree(tree); /* that's the temporary one */
969
970 return ret;
971 }
972
973 /* List rules using struct audit_rule_data. */
974 static void audit_list_rules(int pid, int seq, struct sk_buff_head *q)
975 {
976 struct sk_buff *skb;
977 struct audit_krule *r;
978 int i;
979
980 /* This is a blocking read, so use audit_filter_mutex instead of rcu
981 * iterator to sync with list writers. */
982 for (i=0; i<AUDIT_NR_FILTERS; i++) {
983 list_for_each_entry(r, &audit_rules_list[i], list) {
984 struct audit_rule_data *data;
985
986 data = audit_krule_to_data(r);
987 if (unlikely(!data))
988 break;
989 skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 0, 1,
990 data, sizeof(*data) + data->buflen);
991 if (skb)
992 skb_queue_tail(q, skb);
993 kfree(data);
994 }
995 }
996 skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);
997 if (skb)
998 skb_queue_tail(q, skb);
999 }
1000
1001 /* Log rule additions and removals */
1002 static void audit_log_rule_change(char *action, struct audit_krule *rule, int res)
1003 {
1004 struct audit_buffer *ab;
1005 uid_t loginuid = from_kuid(&init_user_ns, audit_get_loginuid(current));
1006 u32 sessionid = audit_get_sessionid(current);
1007
1008 if (!audit_enabled)
1009 return;
1010
1011 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
1012 if (!ab)
1013 return;
1014 audit_log_format(ab, "auid=%u ses=%u" ,loginuid, sessionid);
1015 audit_log_task_context(ab);
1016 audit_log_format(ab, " op=");
1017 audit_log_string(ab, action);
1018 audit_log_key(ab, rule->filterkey);
1019 audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
1020 audit_log_end(ab);
1021 }
1022
1023 /**
1024 * audit_receive_filter - apply all rules to the specified message type
1025 * @type: audit message type
1026 * @pid: target pid for netlink audit messages
1027 * @seq: netlink audit message sequence (serial) number
1028 * @data: payload data
1029 * @datasz: size of payload data
1030 */
1031 int audit_receive_filter(int type, int pid, int seq, void *data, size_t datasz)
1032 {
1033 struct task_struct *tsk;
1034 struct audit_netlink_list *dest;
1035 int err = 0;
1036 struct audit_entry *entry;
1037
1038 switch (type) {
1039 case AUDIT_LIST_RULES:
1040 /* We can't just spew out the rules here because we might fill
1041 * the available socket buffer space and deadlock waiting for
1042 * auditctl to read from it... which isn't ever going to
1043 * happen if we're actually running in the context of auditctl
1044 * trying to _send_ the stuff */
1045
1046 dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL);
1047 if (!dest)
1048 return -ENOMEM;
1049 dest->pid = pid;
1050 skb_queue_head_init(&dest->q);
1051
1052 mutex_lock(&audit_filter_mutex);
1053 audit_list_rules(pid, seq, &dest->q);
1054 mutex_unlock(&audit_filter_mutex);
1055
1056 tsk = kthread_run(audit_send_list, dest, "audit_send_list");
1057 if (IS_ERR(tsk)) {
1058 skb_queue_purge(&dest->q);
1059 kfree(dest);
1060 err = PTR_ERR(tsk);
1061 }
1062 break;
1063 case AUDIT_ADD_RULE:
1064 entry = audit_data_to_entry(data, datasz);
1065 if (IS_ERR(entry))
1066 return PTR_ERR(entry);
1067
1068 err = audit_add_rule(entry);
1069 audit_log_rule_change("add rule", &entry->rule, !err);
1070 if (err)
1071 audit_free_rule(entry);
1072 break;
1073 case AUDIT_DEL_RULE:
1074 entry = audit_data_to_entry(data, datasz);
1075 if (IS_ERR(entry))
1076 return PTR_ERR(entry);
1077
1078 err = audit_del_rule(entry);
1079 audit_log_rule_change("remove rule", &entry->rule, !err);
1080 audit_free_rule(entry);
1081 break;
1082 default:
1083 return -EINVAL;
1084 }
1085
1086 return err;
1087 }
1088
1089 int audit_comparator(u32 left, u32 op, u32 right)
1090 {
1091 switch (op) {
1092 case Audit_equal:
1093 return (left == right);
1094 case Audit_not_equal:
1095 return (left != right);
1096 case Audit_lt:
1097 return (left < right);
1098 case Audit_le:
1099 return (left <= right);
1100 case Audit_gt:
1101 return (left > right);
1102 case Audit_ge:
1103 return (left >= right);
1104 case Audit_bitmask:
1105 return (left & right);
1106 case Audit_bittest:
1107 return ((left & right) == right);
1108 default:
1109 BUG();
1110 return 0;
1111 }
1112 }
1113
1114 int audit_uid_comparator(kuid_t left, u32 op, kuid_t right)
1115 {
1116 switch (op) {
1117 case Audit_equal:
1118 return uid_eq(left, right);
1119 case Audit_not_equal:
1120 return !uid_eq(left, right);
1121 case Audit_lt:
1122 return uid_lt(left, right);
1123 case Audit_le:
1124 return uid_lte(left, right);
1125 case Audit_gt:
1126 return uid_gt(left, right);
1127 case Audit_ge:
1128 return uid_gte(left, right);
1129 case Audit_bitmask:
1130 case Audit_bittest:
1131 default:
1132 BUG();
1133 return 0;
1134 }
1135 }
1136
1137 int audit_gid_comparator(kgid_t left, u32 op, kgid_t right)
1138 {
1139 switch (op) {
1140 case Audit_equal:
1141 return gid_eq(left, right);
1142 case Audit_not_equal:
1143 return !gid_eq(left, right);
1144 case Audit_lt:
1145 return gid_lt(left, right);
1146 case Audit_le:
1147 return gid_lte(left, right);
1148 case Audit_gt:
1149 return gid_gt(left, right);
1150 case Audit_ge:
1151 return gid_gte(left, right);
1152 case Audit_bitmask:
1153 case Audit_bittest:
1154 default:
1155 BUG();
1156 return 0;
1157 }
1158 }
1159
1160 /**
1161 * parent_len - find the length of the parent portion of a pathname
1162 * @path: pathname of which to determine length
1163 */
1164 int parent_len(const char *path)
1165 {
1166 int plen;
1167 const char *p;
1168
1169 plen = strlen(path);
1170
1171 if (plen == 0)
1172 return plen;
1173
1174 /* disregard trailing slashes */
1175 p = path + plen - 1;
1176 while ((*p == '/') && (p > path))
1177 p--;
1178
1179 /* walk backward until we find the next slash or hit beginning */
1180 while ((*p != '/') && (p > path))
1181 p--;
1182
1183 /* did we find a slash? Then increment to include it in path */
1184 if (*p == '/')
1185 p++;
1186
1187 return p - path;
1188 }
1189
1190 /**
1191 * audit_compare_dname_path - compare given dentry name with last component in
1192 * given path. Return of 0 indicates a match.
1193 * @dname: dentry name that we're comparing
1194 * @path: full pathname that we're comparing
1195 * @parentlen: length of the parent if known. Passing in AUDIT_NAME_FULL
1196 * here indicates that we must compute this value.
1197 */
1198 int audit_compare_dname_path(const char *dname, const char *path, int parentlen)
1199 {
1200 int dlen, pathlen;
1201 const char *p;
1202
1203 dlen = strlen(dname);
1204 pathlen = strlen(path);
1205 if (pathlen < dlen)
1206 return 1;
1207
1208 parentlen = parentlen == AUDIT_NAME_FULL ? parent_len(path) : parentlen;
1209 if (pathlen - parentlen != dlen)
1210 return 1;
1211
1212 p = path + parentlen;
1213
1214 return strncmp(p, dname, dlen);
1215 }
1216
1217 static int audit_filter_user_rules(struct audit_krule *rule, int type,
1218 enum audit_state *state)
1219 {
1220 int i;
1221
1222 for (i = 0; i < rule->field_count; i++) {
1223 struct audit_field *f = &rule->fields[i];
1224 int result = 0;
1225 u32 sid;
1226
1227 switch (f->type) {
1228 case AUDIT_PID:
1229 result = audit_comparator(task_pid_vnr(current), f->op, f->val);
1230 break;
1231 case AUDIT_UID:
1232 result = audit_uid_comparator(current_uid(), f->op, f->uid);
1233 break;
1234 case AUDIT_GID:
1235 result = audit_gid_comparator(current_gid(), f->op, f->gid);
1236 break;
1237 case AUDIT_LOGINUID:
1238 result = audit_uid_comparator(audit_get_loginuid(current),
1239 f->op, f->uid);
1240 break;
1241 case AUDIT_LOGINUID_SET:
1242 result = audit_comparator(audit_loginuid_set(current),
1243 f->op, f->val);
1244 break;
1245 case AUDIT_MSGTYPE:
1246 result = audit_comparator(type, f->op, f->val);
1247 break;
1248 case AUDIT_SUBJ_USER:
1249 case AUDIT_SUBJ_ROLE:
1250 case AUDIT_SUBJ_TYPE:
1251 case AUDIT_SUBJ_SEN:
1252 case AUDIT_SUBJ_CLR:
1253 if (f->lsm_rule) {
1254 security_task_getsecid(current, &sid);
1255 result = security_audit_rule_match(sid,
1256 f->type,
1257 f->op,
1258 f->lsm_rule,
1259 NULL);
1260 }
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(int type)
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(&e->rule, type, &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 int err = 0;
1326
1327 if (!security_audit_rule_known(r))
1328 return 0;
1329
1330 nentry = audit_dupe_rule(r);
1331 if (IS_ERR(nentry)) {
1332 /* save the first error encountered for the
1333 * return value */
1334 err = PTR_ERR(nentry);
1335 audit_panic("error updating LSM filters");
1336 if (r->watch)
1337 list_del(&r->rlist);
1338 list_del_rcu(&entry->list);
1339 list_del(&r->list);
1340 } else {
1341 if (r->watch || r->tree)
1342 list_replace_init(&r->rlist, &nentry->rule.rlist);
1343 list_replace_rcu(&entry->list, &nentry->list);
1344 list_replace(&r->list, &nentry->rule.list);
1345 }
1346 call_rcu(&entry->rcu, audit_free_rule_rcu);
1347
1348 return err;
1349 }
1350
1351 /* This function will re-initialize the lsm_rule field of all applicable rules.
1352 * It will traverse the filter lists serarching for rules that contain LSM
1353 * specific filter fields. When such a rule is found, it is copied, the
1354 * LSM field is re-initialized, and the old rule is replaced with the
1355 * updated rule. */
1356 int audit_update_lsm_rules(void)
1357 {
1358 struct audit_krule *r, *n;
1359 int i, err = 0;
1360
1361 /* audit_filter_mutex synchronizes the writers */
1362 mutex_lock(&audit_filter_mutex);
1363
1364 for (i = 0; i < AUDIT_NR_FILTERS; i++) {
1365 list_for_each_entry_safe(r, n, &audit_rules_list[i], list) {
1366 int res = update_lsm_rule(r);
1367 if (!err)
1368 err = res;
1369 }
1370 }
1371 mutex_unlock(&audit_filter_mutex);
1372
1373 return err;
1374 }
Linus' kernel tree