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mm: oom_kill: clean up victim marking and exiting interfaces
[deliverable/linux.git] / kernel / auditfilter.c
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 for (i = 0; i < data->field_count; i++) {
429 struct audit_field *f = &entry->rule.fields[i];
430
431 err = -EINVAL;
432
433 f->op = audit_to_op(data->fieldflags[i]);
434 if (f->op == Audit_bad)
435 goto exit_free;
436
437 f->type = data->fields[i];
438 f->val = data->values[i];
439
440 /* Support legacy tests for a valid loginuid */
441 if ((f->type == AUDIT_LOGINUID) && (f->val == AUDIT_UID_UNSET)) {
442 f->type = AUDIT_LOGINUID_SET;
443 f->val = 0;
444 entry->rule.pflags |= AUDIT_LOGINUID_LEGACY;
445 }
446
447 err = audit_field_valid(entry, f);
448 if (err)
449 goto exit_free;
450
451 err = -EINVAL;
452 switch (f->type) {
453 case AUDIT_LOGINUID:
454 case AUDIT_UID:
455 case AUDIT_EUID:
456 case AUDIT_SUID:
457 case AUDIT_FSUID:
458 case AUDIT_OBJ_UID:
459 f->uid = make_kuid(current_user_ns(), f->val);
460 if (!uid_valid(f->uid))
461 goto exit_free;
462 break;
463 case AUDIT_GID:
464 case AUDIT_EGID:
465 case AUDIT_SGID:
466 case AUDIT_FSGID:
467 case AUDIT_OBJ_GID:
468 f->gid = make_kgid(current_user_ns(), f->val);
469 if (!gid_valid(f->gid))
470 goto exit_free;
471 break;
472 case AUDIT_ARCH:
473 entry->rule.arch_f = f;
474 break;
475 case AUDIT_SUBJ_USER:
476 case AUDIT_SUBJ_ROLE:
477 case AUDIT_SUBJ_TYPE:
478 case AUDIT_SUBJ_SEN:
479 case AUDIT_SUBJ_CLR:
480 case AUDIT_OBJ_USER:
481 case AUDIT_OBJ_ROLE:
482 case AUDIT_OBJ_TYPE:
483 case AUDIT_OBJ_LEV_LOW:
484 case AUDIT_OBJ_LEV_HIGH:
485 str = audit_unpack_string(&bufp, &remain, f->val);
486 if (IS_ERR(str))
487 goto exit_free;
488 entry->rule.buflen += f->val;
489
490 err = security_audit_rule_init(f->type, f->op, str,
491 (void **)&f->lsm_rule);
492 /* Keep currently invalid fields around in case they
493 * become valid after a policy reload. */
494 if (err == -EINVAL) {
495 pr_warn("audit rule for LSM \'%s\' is invalid\n",
496 str);
497 err = 0;
498 }
499 if (err) {
500 kfree(str);
501 goto exit_free;
502 } else
503 f->lsm_str = str;
504 break;
505 case AUDIT_WATCH:
506 str = audit_unpack_string(&bufp, &remain, f->val);
507 if (IS_ERR(str))
508 goto exit_free;
509 entry->rule.buflen += f->val;
510
511 err = audit_to_watch(&entry->rule, str, f->val, f->op);
512 if (err) {
513 kfree(str);
514 goto exit_free;
515 }
516 break;
517 case AUDIT_DIR:
518 str = audit_unpack_string(&bufp, &remain, f->val);
519 if (IS_ERR(str))
520 goto exit_free;
521 entry->rule.buflen += f->val;
522
523 err = audit_make_tree(&entry->rule, str, f->op);
524 kfree(str);
525 if (err)
526 goto exit_free;
527 break;
528 case AUDIT_INODE:
529 err = audit_to_inode(&entry->rule, f);
530 if (err)
531 goto exit_free;
532 break;
533 case AUDIT_FILTERKEY:
534 if (entry->rule.filterkey || f->val > AUDIT_MAX_KEY_LEN)
535 goto exit_free;
536 str = audit_unpack_string(&bufp, &remain, f->val);
537 if (IS_ERR(str))
538 goto exit_free;
539 entry->rule.buflen += f->val;
540 entry->rule.filterkey = str;
541 break;
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 if (entry->rule.watch)
553 audit_put_watch(entry->rule.watch); /* matches initial get */
554 if (entry->rule.tree)
555 audit_put_tree(entry->rule.tree); /* that's the temporary one */
556 audit_free_rule(entry);
557 return ERR_PTR(err);
558 }
559
560 /* Pack a filter field's string representation into data block. */
561 static inline size_t audit_pack_string(void **bufp, const char *str)
562 {
563 size_t len = strlen(str);
564
565 memcpy(*bufp, str, len);
566 *bufp += len;
567
568 return len;
569 }
570
571 /* Translate kernel rule respresentation to struct audit_rule_data. */
572 static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule)
573 {
574 struct audit_rule_data *data;
575 void *bufp;
576 int i;
577
578 data = kmalloc(sizeof(*data) + krule->buflen, GFP_KERNEL);
579 if (unlikely(!data))
580 return NULL;
581 memset(data, 0, sizeof(*data));
582
583 data->flags = krule->flags | krule->listnr;
584 data->action = krule->action;
585 data->field_count = krule->field_count;
586 bufp = data->buf;
587 for (i = 0; i < data->field_count; i++) {
588 struct audit_field *f = &krule->fields[i];
589
590 data->fields[i] = f->type;
591 data->fieldflags[i] = audit_ops[f->op];
592 switch(f->type) {
593 case AUDIT_SUBJ_USER:
594 case AUDIT_SUBJ_ROLE:
595 case AUDIT_SUBJ_TYPE:
596 case AUDIT_SUBJ_SEN:
597 case AUDIT_SUBJ_CLR:
598 case AUDIT_OBJ_USER:
599 case AUDIT_OBJ_ROLE:
600 case AUDIT_OBJ_TYPE:
601 case AUDIT_OBJ_LEV_LOW:
602 case AUDIT_OBJ_LEV_HIGH:
603 data->buflen += data->values[i] =
604 audit_pack_string(&bufp, f->lsm_str);
605 break;
606 case AUDIT_WATCH:
607 data->buflen += data->values[i] =
608 audit_pack_string(&bufp,
609 audit_watch_path(krule->watch));
610 break;
611 case AUDIT_DIR:
612 data->buflen += data->values[i] =
613 audit_pack_string(&bufp,
614 audit_tree_path(krule->tree));
615 break;
616 case AUDIT_FILTERKEY:
617 data->buflen += data->values[i] =
618 audit_pack_string(&bufp, krule->filterkey);
619 break;
620 case AUDIT_LOGINUID_SET:
621 if (krule->pflags & AUDIT_LOGINUID_LEGACY && !f->val) {
622 data->fields[i] = AUDIT_LOGINUID;
623 data->values[i] = AUDIT_UID_UNSET;
624 break;
625 }
626 /* fallthrough if set */
627 default:
628 data->values[i] = f->val;
629 }
630 }
631 for (i = 0; i < AUDIT_BITMASK_SIZE; i++) data->mask[i] = krule->mask[i];
632
633 return data;
634 }
635
636 /* Compare two rules in kernel format. Considered success if rules
637 * don't match. */
638 static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
639 {
640 int i;
641
642 if (a->flags != b->flags ||
643 a->pflags != b->pflags ||
644 a->listnr != b->listnr ||
645 a->action != b->action ||
646 a->field_count != b->field_count)
647 return 1;
648
649 for (i = 0; i < a->field_count; i++) {
650 if (a->fields[i].type != b->fields[i].type ||
651 a->fields[i].op != b->fields[i].op)
652 return 1;
653
654 switch(a->fields[i].type) {
655 case AUDIT_SUBJ_USER:
656 case AUDIT_SUBJ_ROLE:
657 case AUDIT_SUBJ_TYPE:
658 case AUDIT_SUBJ_SEN:
659 case AUDIT_SUBJ_CLR:
660 case AUDIT_OBJ_USER:
661 case AUDIT_OBJ_ROLE:
662 case AUDIT_OBJ_TYPE:
663 case AUDIT_OBJ_LEV_LOW:
664 case AUDIT_OBJ_LEV_HIGH:
665 if (strcmp(a->fields[i].lsm_str, b->fields[i].lsm_str))
666 return 1;
667 break;
668 case AUDIT_WATCH:
669 if (strcmp(audit_watch_path(a->watch),
670 audit_watch_path(b->watch)))
671 return 1;
672 break;
673 case AUDIT_DIR:
674 if (strcmp(audit_tree_path(a->tree),
675 audit_tree_path(b->tree)))
676 return 1;
677 break;
678 case AUDIT_FILTERKEY:
679 /* both filterkeys exist based on above type compare */
680 if (strcmp(a->filterkey, b->filterkey))
681 return 1;
682 break;
683 case AUDIT_UID:
684 case AUDIT_EUID:
685 case AUDIT_SUID:
686 case AUDIT_FSUID:
687 case AUDIT_LOGINUID:
688 case AUDIT_OBJ_UID:
689 if (!uid_eq(a->fields[i].uid, b->fields[i].uid))
690 return 1;
691 break;
692 case AUDIT_GID:
693 case AUDIT_EGID:
694 case AUDIT_SGID:
695 case AUDIT_FSGID:
696 case AUDIT_OBJ_GID:
697 if (!gid_eq(a->fields[i].gid, b->fields[i].gid))
698 return 1;
699 break;
700 default:
701 if (a->fields[i].val != b->fields[i].val)
702 return 1;
703 }
704 }
705
706 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
707 if (a->mask[i] != b->mask[i])
708 return 1;
709
710 return 0;
711 }
712
713 /* Duplicate LSM field information. The lsm_rule is opaque, so must be
714 * re-initialized. */
715 static inline int audit_dupe_lsm_field(struct audit_field *df,
716 struct audit_field *sf)
717 {
718 int ret = 0;
719 char *lsm_str;
720
721 /* our own copy of lsm_str */
722 lsm_str = kstrdup(sf->lsm_str, GFP_KERNEL);
723 if (unlikely(!lsm_str))
724 return -ENOMEM;
725 df->lsm_str = lsm_str;
726
727 /* our own (refreshed) copy of lsm_rule */
728 ret = security_audit_rule_init(df->type, df->op, df->lsm_str,
729 (void **)&df->lsm_rule);
730 /* Keep currently invalid fields around in case they
731 * become valid after a policy reload. */
732 if (ret == -EINVAL) {
733 pr_warn("audit rule for LSM \'%s\' is invalid\n",
734 df->lsm_str);
735 ret = 0;
736 }
737
738 return ret;
739 }
740
741 /* Duplicate an audit rule. This will be a deep copy with the exception
742 * of the watch - that pointer is carried over. The LSM specific fields
743 * will be updated in the copy. The point is to be able to replace the old
744 * rule with the new rule in the filterlist, then free the old rule.
745 * The rlist element is undefined; list manipulations are handled apart from
746 * the initial copy. */
747 struct audit_entry *audit_dupe_rule(struct audit_krule *old)
748 {
749 u32 fcount = old->field_count;
750 struct audit_entry *entry;
751 struct audit_krule *new;
752 char *fk;
753 int i, err = 0;
754
755 entry = audit_init_entry(fcount);
756 if (unlikely(!entry))
757 return ERR_PTR(-ENOMEM);
758
759 new = &entry->rule;
760 new->flags = old->flags;
761 new->pflags = old->pflags;
762 new->listnr = old->listnr;
763 new->action = old->action;
764 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
765 new->mask[i] = old->mask[i];
766 new->prio = old->prio;
767 new->buflen = old->buflen;
768 new->inode_f = old->inode_f;
769 new->field_count = old->field_count;
770
771 /*
772 * note that we are OK with not refcounting here; audit_match_tree()
773 * never dereferences tree and we can't get false positives there
774 * since we'd have to have rule gone from the list *and* removed
775 * before the chunks found by lookup had been allocated, i.e. before
776 * the beginning of list scan.
777 */
778 new->tree = old->tree;
779 memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount);
780
781 /* deep copy this information, updating the lsm_rule fields, because
782 * the originals will all be freed when the old rule is freed. */
783 for (i = 0; i < fcount; i++) {
784 switch (new->fields[i].type) {
785 case AUDIT_SUBJ_USER:
786 case AUDIT_SUBJ_ROLE:
787 case AUDIT_SUBJ_TYPE:
788 case AUDIT_SUBJ_SEN:
789 case AUDIT_SUBJ_CLR:
790 case AUDIT_OBJ_USER:
791 case AUDIT_OBJ_ROLE:
792 case AUDIT_OBJ_TYPE:
793 case AUDIT_OBJ_LEV_LOW:
794 case AUDIT_OBJ_LEV_HIGH:
795 err = audit_dupe_lsm_field(&new->fields[i],
796 &old->fields[i]);
797 break;
798 case AUDIT_FILTERKEY:
799 fk = kstrdup(old->filterkey, GFP_KERNEL);
800 if (unlikely(!fk))
801 err = -ENOMEM;
802 else
803 new->filterkey = fk;
804 }
805 if (err) {
806 audit_free_rule(entry);
807 return ERR_PTR(err);
808 }
809 }
810
811 if (old->watch) {
812 audit_get_watch(old->watch);
813 new->watch = old->watch;
814 }
815
816 return entry;
817 }
818
819 /* Find an existing audit rule.
820 * Caller must hold audit_filter_mutex to prevent stale rule data. */
821 static struct audit_entry *audit_find_rule(struct audit_entry *entry,
822 struct list_head **p)
823 {
824 struct audit_entry *e, *found = NULL;
825 struct list_head *list;
826 int h;
827
828 if (entry->rule.inode_f) {
829 h = audit_hash_ino(entry->rule.inode_f->val);
830 *p = list = &audit_inode_hash[h];
831 } else if (entry->rule.watch) {
832 /* we don't know the inode number, so must walk entire hash */
833 for (h = 0; h < AUDIT_INODE_BUCKETS; h++) {
834 list = &audit_inode_hash[h];
835 list_for_each_entry(e, list, list)
836 if (!audit_compare_rule(&entry->rule, &e->rule)) {
837 found = e;
838 goto out;
839 }
840 }
841 goto out;
842 } else {
843 *p = list = &audit_filter_list[entry->rule.listnr];
844 }
845
846 list_for_each_entry(e, list, list)
847 if (!audit_compare_rule(&entry->rule, &e->rule)) {
848 found = e;
849 goto out;
850 }
851
852 out:
853 return found;
854 }
855
856 static u64 prio_low = ~0ULL/2;
857 static u64 prio_high = ~0ULL/2 - 1;
858
859 /* Add rule to given filterlist if not a duplicate. */
860 static inline int audit_add_rule(struct audit_entry *entry)
861 {
862 struct audit_entry *e;
863 struct audit_watch *watch = entry->rule.watch;
864 struct audit_tree *tree = entry->rule.tree;
865 struct list_head *list;
866 int err;
867 #ifdef CONFIG_AUDITSYSCALL
868 int dont_count = 0;
869
870 /* If either of these, don't count towards total */
871 if (entry->rule.listnr == AUDIT_FILTER_USER ||
872 entry->rule.listnr == AUDIT_FILTER_TYPE)
873 dont_count = 1;
874 #endif
875
876 mutex_lock(&audit_filter_mutex);
877 e = audit_find_rule(entry, &list);
878 if (e) {
879 mutex_unlock(&audit_filter_mutex);
880 err = -EEXIST;
881 /* normally audit_add_tree_rule() will free it on failure */
882 if (tree)
883 audit_put_tree(tree);
884 goto error;
885 }
886
887 if (watch) {
888 /* audit_filter_mutex is dropped and re-taken during this call */
889 err = audit_add_watch(&entry->rule, &list);
890 if (err) {
891 mutex_unlock(&audit_filter_mutex);
892 /*
893 * normally audit_add_tree_rule() will free it
894 * on failure
895 */
896 if (tree)
897 audit_put_tree(tree);
898 goto error;
899 }
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 int ret = 0;
952 #ifdef CONFIG_AUDITSYSCALL
953 int dont_count = 0;
954
955 /* If either of these, don't count towards total */
956 if (entry->rule.listnr == AUDIT_FILTER_USER ||
957 entry->rule.listnr == AUDIT_FILTER_TYPE)
958 dont_count = 1;
959 #endif
960
961 mutex_lock(&audit_filter_mutex);
962 e = audit_find_rule(entry, &list);
963 if (!e) {
964 mutex_unlock(&audit_filter_mutex);
965 ret = -ENOENT;
966 goto out;
967 }
968
969 if (e->rule.watch)
970 audit_remove_watch_rule(&e->rule);
971
972 if (e->rule.tree)
973 audit_remove_tree_rule(&e->rule);
974
975 list_del_rcu(&e->list);
976 list_del(&e->rule.list);
977 call_rcu(&e->rcu, audit_free_rule_rcu);
978
979 #ifdef CONFIG_AUDITSYSCALL
980 if (!dont_count)
981 audit_n_rules--;
982
983 if (!audit_match_signal(entry))
984 audit_signals--;
985 #endif
986 mutex_unlock(&audit_filter_mutex);
987
988 out:
989 if (watch)
990 audit_put_watch(watch); /* match initial get */
991 if (tree)
992 audit_put_tree(tree); /* that's the temporary one */
993
994 return ret;
995 }
996
997 /* List rules using struct audit_rule_data. */
998 static void audit_list_rules(__u32 portid, int seq, struct sk_buff_head *q)
999 {
1000 struct sk_buff *skb;
1001 struct audit_krule *r;
1002 int i;
1003
1004 /* This is a blocking read, so use audit_filter_mutex instead of rcu
1005 * iterator to sync with list writers. */
1006 for (i=0; i<AUDIT_NR_FILTERS; i++) {
1007 list_for_each_entry(r, &audit_rules_list[i], list) {
1008 struct audit_rule_data *data;
1009
1010 data = audit_krule_to_data(r);
1011 if (unlikely(!data))
1012 break;
1013 skb = audit_make_reply(portid, seq, AUDIT_LIST_RULES,
1014 0, 1, data,
1015 sizeof(*data) + data->buflen);
1016 if (skb)
1017 skb_queue_tail(q, skb);
1018 kfree(data);
1019 }
1020 }
1021 skb = audit_make_reply(portid, seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);
1022 if (skb)
1023 skb_queue_tail(q, skb);
1024 }
1025
1026 /* Log rule additions and removals */
1027 static void audit_log_rule_change(char *action, struct audit_krule *rule, int res)
1028 {
1029 struct audit_buffer *ab;
1030 uid_t loginuid = from_kuid(&init_user_ns, audit_get_loginuid(current));
1031 unsigned int sessionid = audit_get_sessionid(current);
1032
1033 if (!audit_enabled)
1034 return;
1035
1036 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
1037 if (!ab)
1038 return;
1039 audit_log_format(ab, "auid=%u ses=%u" ,loginuid, sessionid);
1040 audit_log_task_context(ab);
1041 audit_log_format(ab, " op=");
1042 audit_log_string(ab, action);
1043 audit_log_key(ab, rule->filterkey);
1044 audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
1045 audit_log_end(ab);
1046 }
1047
1048 /**
1049 * audit_rule_change - apply all rules to the specified message type
1050 * @type: audit message type
1051 * @portid: target port id for netlink audit messages
1052 * @seq: netlink audit message sequence (serial) number
1053 * @data: payload data
1054 * @datasz: size of payload data
1055 */
1056 int audit_rule_change(int type, __u32 portid, int seq, void *data,
1057 size_t datasz)
1058 {
1059 int err = 0;
1060 struct audit_entry *entry;
1061
1062 entry = audit_data_to_entry(data, datasz);
1063 if (IS_ERR(entry))
1064 return PTR_ERR(entry);
1065
1066 switch (type) {
1067 case AUDIT_ADD_RULE:
1068 err = audit_add_rule(entry);
1069 audit_log_rule_change("add_rule", &entry->rule, !err);
1070 break;
1071 case AUDIT_DEL_RULE:
1072 err = audit_del_rule(entry);
1073 audit_log_rule_change("remove_rule", &entry->rule, !err);
1074 break;
1075 default:
1076 err = -EINVAL;
1077 WARN_ON(1);
1078 }
1079
1080 if (err || type == AUDIT_DEL_RULE)
1081 audit_free_rule(entry);
1082
1083 return err;
1084 }
1085
1086 /**
1087 * audit_list_rules_send - list the audit rules
1088 * @request_skb: skb of request we are replying to (used to target the reply)
1089 * @seq: netlink audit message sequence (serial) number
1090 */
1091 int audit_list_rules_send(struct sk_buff *request_skb, int seq)
1092 {
1093 u32 portid = NETLINK_CB(request_skb).portid;
1094 struct net *net = sock_net(NETLINK_CB(request_skb).sk);
1095 struct task_struct *tsk;
1096 struct audit_netlink_list *dest;
1097 int err = 0;
1098
1099 /* We can't just spew out the rules here because we might fill
1100 * the available socket buffer space and deadlock waiting for
1101 * auditctl to read from it... which isn't ever going to
1102 * happen if we're actually running in the context of auditctl
1103 * trying to _send_ the stuff */
1104
1105 dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL);
1106 if (!dest)
1107 return -ENOMEM;
1108 dest->net = get_net(net);
1109 dest->portid = portid;
1110 skb_queue_head_init(&dest->q);
1111
1112 mutex_lock(&audit_filter_mutex);
1113 audit_list_rules(portid, seq, &dest->q);
1114 mutex_unlock(&audit_filter_mutex);
1115
1116 tsk = kthread_run(audit_send_list, dest, "audit_send_list");
1117 if (IS_ERR(tsk)) {
1118 skb_queue_purge(&dest->q);
1119 kfree(dest);
1120 err = PTR_ERR(tsk);
1121 }
1122
1123 return err;
1124 }
1125
1126 int audit_comparator(u32 left, u32 op, u32 right)
1127 {
1128 switch (op) {
1129 case Audit_equal:
1130 return (left == right);
1131 case Audit_not_equal:
1132 return (left != right);
1133 case Audit_lt:
1134 return (left < right);
1135 case Audit_le:
1136 return (left <= right);
1137 case Audit_gt:
1138 return (left > right);
1139 case Audit_ge:
1140 return (left >= right);
1141 case Audit_bitmask:
1142 return (left & right);
1143 case Audit_bittest:
1144 return ((left & right) == right);
1145 default:
1146 BUG();
1147 return 0;
1148 }
1149 }
1150
1151 int audit_uid_comparator(kuid_t left, u32 op, kuid_t right)
1152 {
1153 switch (op) {
1154 case Audit_equal:
1155 return uid_eq(left, right);
1156 case Audit_not_equal:
1157 return !uid_eq(left, right);
1158 case Audit_lt:
1159 return uid_lt(left, right);
1160 case Audit_le:
1161 return uid_lte(left, right);
1162 case Audit_gt:
1163 return uid_gt(left, right);
1164 case Audit_ge:
1165 return uid_gte(left, right);
1166 case Audit_bitmask:
1167 case Audit_bittest:
1168 default:
1169 BUG();
1170 return 0;
1171 }
1172 }
1173
1174 int audit_gid_comparator(kgid_t left, u32 op, kgid_t right)
1175 {
1176 switch (op) {
1177 case Audit_equal:
1178 return gid_eq(left, right);
1179 case Audit_not_equal:
1180 return !gid_eq(left, right);
1181 case Audit_lt:
1182 return gid_lt(left, right);
1183 case Audit_le:
1184 return gid_lte(left, right);
1185 case Audit_gt:
1186 return gid_gt(left, right);
1187 case Audit_ge:
1188 return gid_gte(left, right);
1189 case Audit_bitmask:
1190 case Audit_bittest:
1191 default:
1192 BUG();
1193 return 0;
1194 }
1195 }
1196
1197 /**
1198 * parent_len - find the length of the parent portion of a pathname
1199 * @path: pathname of which to determine length
1200 */
1201 int parent_len(const char *path)
1202 {
1203 int plen;
1204 const char *p;
1205
1206 plen = strlen(path);
1207
1208 if (plen == 0)
1209 return plen;
1210
1211 /* disregard trailing slashes */
1212 p = path + plen - 1;
1213 while ((*p == '/') && (p > path))
1214 p--;
1215
1216 /* walk backward until we find the next slash or hit beginning */
1217 while ((*p != '/') && (p > path))
1218 p--;
1219
1220 /* did we find a slash? Then increment to include it in path */
1221 if (*p == '/')
1222 p++;
1223
1224 return p - path;
1225 }
1226
1227 /**
1228 * audit_compare_dname_path - compare given dentry name with last component in
1229 * given path. Return of 0 indicates a match.
1230 * @dname: dentry name that we're comparing
1231 * @path: full pathname that we're comparing
1232 * @parentlen: length of the parent if known. Passing in AUDIT_NAME_FULL
1233 * here indicates that we must compute this value.
1234 */
1235 int audit_compare_dname_path(const char *dname, const char *path, int parentlen)
1236 {
1237 int dlen, pathlen;
1238 const char *p;
1239
1240 dlen = strlen(dname);
1241 pathlen = strlen(path);
1242 if (pathlen < dlen)
1243 return 1;
1244
1245 parentlen = parentlen == AUDIT_NAME_FULL ? parent_len(path) : parentlen;
1246 if (pathlen - parentlen != dlen)
1247 return 1;
1248
1249 p = path + parentlen;
1250
1251 return strncmp(p, dname, dlen);
1252 }
1253
1254 static int audit_filter_user_rules(struct audit_krule *rule, int type,
1255 enum audit_state *state)
1256 {
1257 int i;
1258
1259 for (i = 0; i < rule->field_count; i++) {
1260 struct audit_field *f = &rule->fields[i];
1261 pid_t pid;
1262 int result = 0;
1263 u32 sid;
1264
1265 switch (f->type) {
1266 case AUDIT_PID:
1267 pid = task_pid_nr(current);
1268 result = audit_comparator(pid, f->op, f->val);
1269 break;
1270 case AUDIT_UID:
1271 result = audit_uid_comparator(current_uid(), f->op, f->uid);
1272 break;
1273 case AUDIT_GID:
1274 result = audit_gid_comparator(current_gid(), f->op, f->gid);
1275 break;
1276 case AUDIT_LOGINUID:
1277 result = audit_uid_comparator(audit_get_loginuid(current),
1278 f->op, f->uid);
1279 break;
1280 case AUDIT_LOGINUID_SET:
1281 result = audit_comparator(audit_loginuid_set(current),
1282 f->op, f->val);
1283 break;
1284 case AUDIT_MSGTYPE:
1285 result = audit_comparator(type, f->op, f->val);
1286 break;
1287 case AUDIT_SUBJ_USER:
1288 case AUDIT_SUBJ_ROLE:
1289 case AUDIT_SUBJ_TYPE:
1290 case AUDIT_SUBJ_SEN:
1291 case AUDIT_SUBJ_CLR:
1292 if (f->lsm_rule) {
1293 security_task_getsecid(current, &sid);
1294 result = security_audit_rule_match(sid,
1295 f->type,
1296 f->op,
1297 f->lsm_rule,
1298 NULL);
1299 }
1300 break;
1301 }
1302
1303 if (!result)
1304 return 0;
1305 }
1306 switch (rule->action) {
1307 case AUDIT_NEVER: *state = AUDIT_DISABLED; break;
1308 case AUDIT_ALWAYS: *state = AUDIT_RECORD_CONTEXT; break;
1309 }
1310 return 1;
1311 }
1312
1313 int audit_filter_user(int type)
1314 {
1315 enum audit_state state = AUDIT_DISABLED;
1316 struct audit_entry *e;
1317 int rc, ret;
1318
1319 ret = 1; /* Audit by default */
1320
1321 rcu_read_lock();
1322 list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_USER], list) {
1323 rc = audit_filter_user_rules(&e->rule, type, &state);
1324 if (rc) {
1325 if (rc > 0 && state == AUDIT_DISABLED)
1326 ret = 0;
1327 break;
1328 }
1329 }
1330 rcu_read_unlock();
1331
1332 return ret;
1333 }
1334
1335 int audit_filter_type(int type)
1336 {
1337 struct audit_entry *e;
1338 int result = 0;
1339
1340 rcu_read_lock();
1341 if (list_empty(&audit_filter_list[AUDIT_FILTER_TYPE]))
1342 goto unlock_and_return;
1343
1344 list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_TYPE],
1345 list) {
1346 int i;
1347 for (i = 0; i < e->rule.field_count; i++) {
1348 struct audit_field *f = &e->rule.fields[i];
1349 if (f->type == AUDIT_MSGTYPE) {
1350 result = audit_comparator(type, f->op, f->val);
1351 if (!result)
1352 break;
1353 }
1354 }
1355 if (result)
1356 goto unlock_and_return;
1357 }
1358 unlock_and_return:
1359 rcu_read_unlock();
1360 return result;
1361 }
1362
1363 static int update_lsm_rule(struct audit_krule *r)
1364 {
1365 struct audit_entry *entry = container_of(r, struct audit_entry, rule);
1366 struct audit_entry *nentry;
1367 int err = 0;
1368
1369 if (!security_audit_rule_known(r))
1370 return 0;
1371
1372 nentry = audit_dupe_rule(r);
1373 if (IS_ERR(nentry)) {
1374 /* save the first error encountered for the
1375 * return value */
1376 err = PTR_ERR(nentry);
1377 audit_panic("error updating LSM filters");
1378 if (r->watch)
1379 list_del(&r->rlist);
1380 list_del_rcu(&entry->list);
1381 list_del(&r->list);
1382 } else {
1383 if (r->watch || r->tree)
1384 list_replace_init(&r->rlist, &nentry->rule.rlist);
1385 list_replace_rcu(&entry->list, &nentry->list);
1386 list_replace(&r->list, &nentry->rule.list);
1387 }
1388 call_rcu(&entry->rcu, audit_free_rule_rcu);
1389
1390 return err;
1391 }
1392
1393 /* This function will re-initialize the lsm_rule field of all applicable rules.
1394 * It will traverse the filter lists serarching for rules that contain LSM
1395 * specific filter fields. When such a rule is found, it is copied, the
1396 * LSM field is re-initialized, and the old rule is replaced with the
1397 * updated rule. */
1398 int audit_update_lsm_rules(void)
1399 {
1400 struct audit_krule *r, *n;
1401 int i, err = 0;
1402
1403 /* audit_filter_mutex synchronizes the writers */
1404 mutex_lock(&audit_filter_mutex);
1405
1406 for (i = 0; i < AUDIT_NR_FILTERS; i++) {
1407 list_for_each_entry_safe(r, n, &audit_rules_list[i], list) {
1408 int res = update_lsm_rule(r);
1409 if (!err)
1410 err = res;
1411 }
1412 }
1413 mutex_unlock(&audit_filter_mutex);
1414
1415 return err;
1416 }
Linux kernel - Deliverables
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