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audit: fix uninitialized variable in audit_add_rule()
[GitHub/LineageOS/android_kernel_motorola_exynos9610.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.tree)
553 audit_put_tree(entry->rule.tree); /* that's the temporary one */
554 audit_free_rule(entry);
555 return ERR_PTR(err);
556 }
557
558 /* Pack a filter field's string representation into data block. */
559 static inline size_t audit_pack_string(void **bufp, const char *str)
560 {
561 size_t len = strlen(str);
562
563 memcpy(*bufp, str, len);
564 *bufp += len;
565
566 return len;
567 }
568
569 /* Translate kernel rule respresentation to struct audit_rule_data. */
570 static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule)
571 {
572 struct audit_rule_data *data;
573 void *bufp;
574 int i;
575
576 data = kmalloc(sizeof(*data) + krule->buflen, GFP_KERNEL);
577 if (unlikely(!data))
578 return NULL;
579 memset(data, 0, sizeof(*data));
580
581 data->flags = krule->flags | krule->listnr;
582 data->action = krule->action;
583 data->field_count = krule->field_count;
584 bufp = data->buf;
585 for (i = 0; i < data->field_count; i++) {
586 struct audit_field *f = &krule->fields[i];
587
588 data->fields[i] = f->type;
589 data->fieldflags[i] = audit_ops[f->op];
590 switch(f->type) {
591 case AUDIT_SUBJ_USER:
592 case AUDIT_SUBJ_ROLE:
593 case AUDIT_SUBJ_TYPE:
594 case AUDIT_SUBJ_SEN:
595 case AUDIT_SUBJ_CLR:
596 case AUDIT_OBJ_USER:
597 case AUDIT_OBJ_ROLE:
598 case AUDIT_OBJ_TYPE:
599 case AUDIT_OBJ_LEV_LOW:
600 case AUDIT_OBJ_LEV_HIGH:
601 data->buflen += data->values[i] =
602 audit_pack_string(&bufp, f->lsm_str);
603 break;
604 case AUDIT_WATCH:
605 data->buflen += data->values[i] =
606 audit_pack_string(&bufp,
607 audit_watch_path(krule->watch));
608 break;
609 case AUDIT_DIR:
610 data->buflen += data->values[i] =
611 audit_pack_string(&bufp,
612 audit_tree_path(krule->tree));
613 break;
614 case AUDIT_FILTERKEY:
615 data->buflen += data->values[i] =
616 audit_pack_string(&bufp, krule->filterkey);
617 break;
618 case AUDIT_LOGINUID_SET:
619 if (krule->pflags & AUDIT_LOGINUID_LEGACY && !f->val) {
620 data->fields[i] = AUDIT_LOGINUID;
621 data->values[i] = AUDIT_UID_UNSET;
622 break;
623 }
624 /* fallthrough if set */
625 default:
626 data->values[i] = f->val;
627 }
628 }
629 for (i = 0; i < AUDIT_BITMASK_SIZE; i++) data->mask[i] = krule->mask[i];
630
631 return data;
632 }
633
634 /* Compare two rules in kernel format. Considered success if rules
635 * don't match. */
636 static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
637 {
638 int i;
639
640 if (a->flags != b->flags ||
641 a->pflags != b->pflags ||
642 a->listnr != b->listnr ||
643 a->action != b->action ||
644 a->field_count != b->field_count)
645 return 1;
646
647 for (i = 0; i < a->field_count; i++) {
648 if (a->fields[i].type != b->fields[i].type ||
649 a->fields[i].op != b->fields[i].op)
650 return 1;
651
652 switch(a->fields[i].type) {
653 case AUDIT_SUBJ_USER:
654 case AUDIT_SUBJ_ROLE:
655 case AUDIT_SUBJ_TYPE:
656 case AUDIT_SUBJ_SEN:
657 case AUDIT_SUBJ_CLR:
658 case AUDIT_OBJ_USER:
659 case AUDIT_OBJ_ROLE:
660 case AUDIT_OBJ_TYPE:
661 case AUDIT_OBJ_LEV_LOW:
662 case AUDIT_OBJ_LEV_HIGH:
663 if (strcmp(a->fields[i].lsm_str, b->fields[i].lsm_str))
664 return 1;
665 break;
666 case AUDIT_WATCH:
667 if (strcmp(audit_watch_path(a->watch),
668 audit_watch_path(b->watch)))
669 return 1;
670 break;
671 case AUDIT_DIR:
672 if (strcmp(audit_tree_path(a->tree),
673 audit_tree_path(b->tree)))
674 return 1;
675 break;
676 case AUDIT_FILTERKEY:
677 /* both filterkeys exist based on above type compare */
678 if (strcmp(a->filterkey, b->filterkey))
679 return 1;
680 break;
681 case AUDIT_UID:
682 case AUDIT_EUID:
683 case AUDIT_SUID:
684 case AUDIT_FSUID:
685 case AUDIT_LOGINUID:
686 case AUDIT_OBJ_UID:
687 if (!uid_eq(a->fields[i].uid, b->fields[i].uid))
688 return 1;
689 break;
690 case AUDIT_GID:
691 case AUDIT_EGID:
692 case AUDIT_SGID:
693 case AUDIT_FSGID:
694 case AUDIT_OBJ_GID:
695 if (!gid_eq(a->fields[i].gid, b->fields[i].gid))
696 return 1;
697 break;
698 default:
699 if (a->fields[i].val != b->fields[i].val)
700 return 1;
701 }
702 }
703
704 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
705 if (a->mask[i] != b->mask[i])
706 return 1;
707
708 return 0;
709 }
710
711 /* Duplicate LSM field information. The lsm_rule is opaque, so must be
712 * re-initialized. */
713 static inline int audit_dupe_lsm_field(struct audit_field *df,
714 struct audit_field *sf)
715 {
716 int ret = 0;
717 char *lsm_str;
718
719 /* our own copy of lsm_str */
720 lsm_str = kstrdup(sf->lsm_str, GFP_KERNEL);
721 if (unlikely(!lsm_str))
722 return -ENOMEM;
723 df->lsm_str = lsm_str;
724
725 /* our own (refreshed) copy of lsm_rule */
726 ret = security_audit_rule_init(df->type, df->op, df->lsm_str,
727 (void **)&df->lsm_rule);
728 /* Keep currently invalid fields around in case they
729 * become valid after a policy reload. */
730 if (ret == -EINVAL) {
731 pr_warn("audit rule for LSM \'%s\' is invalid\n",
732 df->lsm_str);
733 ret = 0;
734 }
735
736 return ret;
737 }
738
739 /* Duplicate an audit rule. This will be a deep copy with the exception
740 * of the watch - that pointer is carried over. The LSM specific fields
741 * will be updated in the copy. The point is to be able to replace the old
742 * rule with the new rule in the filterlist, then free the old rule.
743 * The rlist element is undefined; list manipulations are handled apart from
744 * the initial copy. */
745 struct audit_entry *audit_dupe_rule(struct audit_krule *old)
746 {
747 u32 fcount = old->field_count;
748 struct audit_entry *entry;
749 struct audit_krule *new;
750 char *fk;
751 int i, err = 0;
752
753 entry = audit_init_entry(fcount);
754 if (unlikely(!entry))
755 return ERR_PTR(-ENOMEM);
756
757 new = &entry->rule;
758 new->flags = old->flags;
759 new->pflags = old->pflags;
760 new->listnr = old->listnr;
761 new->action = old->action;
762 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
763 new->mask[i] = old->mask[i];
764 new->prio = old->prio;
765 new->buflen = old->buflen;
766 new->inode_f = old->inode_f;
767 new->field_count = old->field_count;
768
769 /*
770 * note that we are OK with not refcounting here; audit_match_tree()
771 * never dereferences tree and we can't get false positives there
772 * since we'd have to have rule gone from the list *and* removed
773 * before the chunks found by lookup had been allocated, i.e. before
774 * the beginning of list scan.
775 */
776 new->tree = old->tree;
777 memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount);
778
779 /* deep copy this information, updating the lsm_rule fields, because
780 * the originals will all be freed when the old rule is freed. */
781 for (i = 0; i < fcount; i++) {
782 switch (new->fields[i].type) {
783 case AUDIT_SUBJ_USER:
784 case AUDIT_SUBJ_ROLE:
785 case AUDIT_SUBJ_TYPE:
786 case AUDIT_SUBJ_SEN:
787 case AUDIT_SUBJ_CLR:
788 case AUDIT_OBJ_USER:
789 case AUDIT_OBJ_ROLE:
790 case AUDIT_OBJ_TYPE:
791 case AUDIT_OBJ_LEV_LOW:
792 case AUDIT_OBJ_LEV_HIGH:
793 err = audit_dupe_lsm_field(&new->fields[i],
794 &old->fields[i]);
795 break;
796 case AUDIT_FILTERKEY:
797 fk = kstrdup(old->filterkey, GFP_KERNEL);
798 if (unlikely(!fk))
799 err = -ENOMEM;
800 else
801 new->filterkey = fk;
802 }
803 if (err) {
804 audit_free_rule(entry);
805 return ERR_PTR(err);
806 }
807 }
808
809 if (old->watch) {
810 audit_get_watch(old->watch);
811 new->watch = old->watch;
812 }
813
814 return entry;
815 }
816
817 /* Find an existing audit rule.
818 * Caller must hold audit_filter_mutex to prevent stale rule data. */
819 static struct audit_entry *audit_find_rule(struct audit_entry *entry,
820 struct list_head **p)
821 {
822 struct audit_entry *e, *found = NULL;
823 struct list_head *list;
824 int h;
825
826 if (entry->rule.inode_f) {
827 h = audit_hash_ino(entry->rule.inode_f->val);
828 *p = list = &audit_inode_hash[h];
829 } else if (entry->rule.watch) {
830 /* we don't know the inode number, so must walk entire hash */
831 for (h = 0; h < AUDIT_INODE_BUCKETS; h++) {
832 list = &audit_inode_hash[h];
833 list_for_each_entry(e, list, list)
834 if (!audit_compare_rule(&entry->rule, &e->rule)) {
835 found = e;
836 goto out;
837 }
838 }
839 goto out;
840 } else {
841 *p = list = &audit_filter_list[entry->rule.listnr];
842 }
843
844 list_for_each_entry(e, list, list)
845 if (!audit_compare_rule(&entry->rule, &e->rule)) {
846 found = e;
847 goto out;
848 }
849
850 out:
851 return found;
852 }
853
854 static u64 prio_low = ~0ULL/2;
855 static u64 prio_high = ~0ULL/2 - 1;
856
857 /* Add rule to given filterlist if not a duplicate. */
858 static inline int audit_add_rule(struct audit_entry *entry)
859 {
860 struct audit_entry *e;
861 struct audit_watch *watch = entry->rule.watch;
862 struct audit_tree *tree = entry->rule.tree;
863 struct list_head *list;
864 int err = 0;
865 #ifdef CONFIG_AUDITSYSCALL
866 int dont_count = 0;
867
868 /* If either of these, don't count towards total */
869 if (entry->rule.listnr == AUDIT_FILTER_USER ||
870 entry->rule.listnr == AUDIT_FILTER_TYPE)
871 dont_count = 1;
872 #endif
873
874 mutex_lock(&audit_filter_mutex);
875 e = audit_find_rule(entry, &list);
876 if (e) {
877 mutex_unlock(&audit_filter_mutex);
878 err = -EEXIST;
879 /* normally audit_add_tree_rule() will free it on failure */
880 if (tree)
881 audit_put_tree(tree);
882 return err;
883 }
884
885 if (watch) {
886 /* audit_filter_mutex is dropped and re-taken during this call */
887 err = audit_add_watch(&entry->rule, &list);
888 if (err) {
889 mutex_unlock(&audit_filter_mutex);
890 /*
891 * normally audit_add_tree_rule() will free it
892 * on failure
893 */
894 if (tree)
895 audit_put_tree(tree);
896 return err;
897 }
898 }
899 if (tree) {
900 err = audit_add_tree_rule(&entry->rule);
901 if (err) {
902 mutex_unlock(&audit_filter_mutex);
903 return err;
904 }
905 }
906
907 entry->rule.prio = ~0ULL;
908 if (entry->rule.listnr == AUDIT_FILTER_EXIT) {
909 if (entry->rule.flags & AUDIT_FILTER_PREPEND)
910 entry->rule.prio = ++prio_high;
911 else
912 entry->rule.prio = --prio_low;
913 }
914
915 if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
916 list_add(&entry->rule.list,
917 &audit_rules_list[entry->rule.listnr]);
918 list_add_rcu(&entry->list, list);
919 entry->rule.flags &= ~AUDIT_FILTER_PREPEND;
920 } else {
921 list_add_tail(&entry->rule.list,
922 &audit_rules_list[entry->rule.listnr]);
923 list_add_tail_rcu(&entry->list, list);
924 }
925 #ifdef CONFIG_AUDITSYSCALL
926 if (!dont_count)
927 audit_n_rules++;
928
929 if (!audit_match_signal(entry))
930 audit_signals++;
931 #endif
932 mutex_unlock(&audit_filter_mutex);
933
934 return err;
935 }
936
937 /* Remove an existing rule from filterlist. */
938 static inline int audit_del_rule(struct audit_entry *entry)
939 {
940 struct audit_entry *e;
941 struct audit_tree *tree = entry->rule.tree;
942 struct list_head *list;
943 int ret = 0;
944 #ifdef CONFIG_AUDITSYSCALL
945 int dont_count = 0;
946
947 /* If either of these, don't count towards total */
948 if (entry->rule.listnr == AUDIT_FILTER_USER ||
949 entry->rule.listnr == AUDIT_FILTER_TYPE)
950 dont_count = 1;
951 #endif
952
953 mutex_lock(&audit_filter_mutex);
954 e = audit_find_rule(entry, &list);
955 if (!e) {
956 mutex_unlock(&audit_filter_mutex);
957 ret = -ENOENT;
958 goto out;
959 }
960
961 if (e->rule.watch)
962 audit_remove_watch_rule(&e->rule);
963
964 if (e->rule.tree)
965 audit_remove_tree_rule(&e->rule);
966
967 list_del_rcu(&e->list);
968 list_del(&e->rule.list);
969 call_rcu(&e->rcu, audit_free_rule_rcu);
970
971 #ifdef CONFIG_AUDITSYSCALL
972 if (!dont_count)
973 audit_n_rules--;
974
975 if (!audit_match_signal(entry))
976 audit_signals--;
977 #endif
978 mutex_unlock(&audit_filter_mutex);
979
980 out:
981 if (tree)
982 audit_put_tree(tree); /* that's the temporary one */
983
984 return ret;
985 }
986
987 /* List rules using struct audit_rule_data. */
988 static void audit_list_rules(__u32 portid, int seq, struct sk_buff_head *q)
989 {
990 struct sk_buff *skb;
991 struct audit_krule *r;
992 int i;
993
994 /* This is a blocking read, so use audit_filter_mutex instead of rcu
995 * iterator to sync with list writers. */
996 for (i=0; i<AUDIT_NR_FILTERS; i++) {
997 list_for_each_entry(r, &audit_rules_list[i], list) {
998 struct audit_rule_data *data;
999
1000 data = audit_krule_to_data(r);
1001 if (unlikely(!data))
1002 break;
1003 skb = audit_make_reply(portid, seq, AUDIT_LIST_RULES,
1004 0, 1, data,
1005 sizeof(*data) + data->buflen);
1006 if (skb)
1007 skb_queue_tail(q, skb);
1008 kfree(data);
1009 }
1010 }
1011 skb = audit_make_reply(portid, seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);
1012 if (skb)
1013 skb_queue_tail(q, skb);
1014 }
1015
1016 /* Log rule additions and removals */
1017 static void audit_log_rule_change(char *action, struct audit_krule *rule, int res)
1018 {
1019 struct audit_buffer *ab;
1020 uid_t loginuid = from_kuid(&init_user_ns, audit_get_loginuid(current));
1021 unsigned int sessionid = audit_get_sessionid(current);
1022
1023 if (!audit_enabled)
1024 return;
1025
1026 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
1027 if (!ab)
1028 return;
1029 audit_log_format(ab, "auid=%u ses=%u" ,loginuid, sessionid);
1030 audit_log_task_context(ab);
1031 audit_log_format(ab, " op=");
1032 audit_log_string(ab, action);
1033 audit_log_key(ab, rule->filterkey);
1034 audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
1035 audit_log_end(ab);
1036 }
1037
1038 /**
1039 * audit_rule_change - apply all rules to the specified message type
1040 * @type: audit message type
1041 * @portid: target port id for netlink audit messages
1042 * @seq: netlink audit message sequence (serial) number
1043 * @data: payload data
1044 * @datasz: size of payload data
1045 */
1046 int audit_rule_change(int type, __u32 portid, int seq, void *data,
1047 size_t datasz)
1048 {
1049 int err = 0;
1050 struct audit_entry *entry;
1051
1052 entry = audit_data_to_entry(data, datasz);
1053 if (IS_ERR(entry))
1054 return PTR_ERR(entry);
1055
1056 switch (type) {
1057 case AUDIT_ADD_RULE:
1058 err = audit_add_rule(entry);
1059 audit_log_rule_change("add_rule", &entry->rule, !err);
1060 break;
1061 case AUDIT_DEL_RULE:
1062 err = audit_del_rule(entry);
1063 audit_log_rule_change("remove_rule", &entry->rule, !err);
1064 break;
1065 default:
1066 err = -EINVAL;
1067 WARN_ON(1);
1068 }
1069
1070 if (err || type == AUDIT_DEL_RULE)
1071 audit_free_rule(entry);
1072
1073 return err;
1074 }
1075
1076 /**
1077 * audit_list_rules_send - list the audit rules
1078 * @request_skb: skb of request we are replying to (used to target the reply)
1079 * @seq: netlink audit message sequence (serial) number
1080 */
1081 int audit_list_rules_send(struct sk_buff *request_skb, int seq)
1082 {
1083 u32 portid = NETLINK_CB(request_skb).portid;
1084 struct net *net = sock_net(NETLINK_CB(request_skb).sk);
1085 struct task_struct *tsk;
1086 struct audit_netlink_list *dest;
1087 int err = 0;
1088
1089 /* We can't just spew out the rules here because we might fill
1090 * the available socket buffer space and deadlock waiting for
1091 * auditctl to read from it... which isn't ever going to
1092 * happen if we're actually running in the context of auditctl
1093 * trying to _send_ the stuff */
1094
1095 dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL);
1096 if (!dest)
1097 return -ENOMEM;
1098 dest->net = get_net(net);
1099 dest->portid = portid;
1100 skb_queue_head_init(&dest->q);
1101
1102 mutex_lock(&audit_filter_mutex);
1103 audit_list_rules(portid, seq, &dest->q);
1104 mutex_unlock(&audit_filter_mutex);
1105
1106 tsk = kthread_run(audit_send_list, dest, "audit_send_list");
1107 if (IS_ERR(tsk)) {
1108 skb_queue_purge(&dest->q);
1109 kfree(dest);
1110 err = PTR_ERR(tsk);
1111 }
1112
1113 return err;
1114 }
1115
1116 int audit_comparator(u32 left, u32 op, u32 right)
1117 {
1118 switch (op) {
1119 case Audit_equal:
1120 return (left == right);
1121 case Audit_not_equal:
1122 return (left != right);
1123 case Audit_lt:
1124 return (left < right);
1125 case Audit_le:
1126 return (left <= right);
1127 case Audit_gt:
1128 return (left > right);
1129 case Audit_ge:
1130 return (left >= right);
1131 case Audit_bitmask:
1132 return (left & right);
1133 case Audit_bittest:
1134 return ((left & right) == right);
1135 default:
1136 BUG();
1137 return 0;
1138 }
1139 }
1140
1141 int audit_uid_comparator(kuid_t left, u32 op, kuid_t right)
1142 {
1143 switch (op) {
1144 case Audit_equal:
1145 return uid_eq(left, right);
1146 case Audit_not_equal:
1147 return !uid_eq(left, right);
1148 case Audit_lt:
1149 return uid_lt(left, right);
1150 case Audit_le:
1151 return uid_lte(left, right);
1152 case Audit_gt:
1153 return uid_gt(left, right);
1154 case Audit_ge:
1155 return uid_gte(left, right);
1156 case Audit_bitmask:
1157 case Audit_bittest:
1158 default:
1159 BUG();
1160 return 0;
1161 }
1162 }
1163
1164 int audit_gid_comparator(kgid_t left, u32 op, kgid_t right)
1165 {
1166 switch (op) {
1167 case Audit_equal:
1168 return gid_eq(left, right);
1169 case Audit_not_equal:
1170 return !gid_eq(left, right);
1171 case Audit_lt:
1172 return gid_lt(left, right);
1173 case Audit_le:
1174 return gid_lte(left, right);
1175 case Audit_gt:
1176 return gid_gt(left, right);
1177 case Audit_ge:
1178 return gid_gte(left, right);
1179 case Audit_bitmask:
1180 case Audit_bittest:
1181 default:
1182 BUG();
1183 return 0;
1184 }
1185 }
1186
1187 /**
1188 * parent_len - find the length of the parent portion of a pathname
1189 * @path: pathname of which to determine length
1190 */
1191 int parent_len(const char *path)
1192 {
1193 int plen;
1194 const char *p;
1195
1196 plen = strlen(path);
1197
1198 if (plen == 0)
1199 return plen;
1200
1201 /* disregard trailing slashes */
1202 p = path + plen - 1;
1203 while ((*p == '/') && (p > path))
1204 p--;
1205
1206 /* walk backward until we find the next slash or hit beginning */
1207 while ((*p != '/') && (p > path))
1208 p--;
1209
1210 /* did we find a slash? Then increment to include it in path */
1211 if (*p == '/')
1212 p++;
1213
1214 return p - path;
1215 }
1216
1217 /**
1218 * audit_compare_dname_path - compare given dentry name with last component in
1219 * given path. Return of 0 indicates a match.
1220 * @dname: dentry name that we're comparing
1221 * @path: full pathname that we're comparing
1222 * @parentlen: length of the parent if known. Passing in AUDIT_NAME_FULL
1223 * here indicates that we must compute this value.
1224 */
1225 int audit_compare_dname_path(const char *dname, const char *path, int parentlen)
1226 {
1227 int dlen, pathlen;
1228 const char *p;
1229
1230 dlen = strlen(dname);
1231 pathlen = strlen(path);
1232 if (pathlen < dlen)
1233 return 1;
1234
1235 parentlen = parentlen == AUDIT_NAME_FULL ? parent_len(path) : parentlen;
1236 if (pathlen - parentlen != dlen)
1237 return 1;
1238
1239 p = path + parentlen;
1240
1241 return strncmp(p, dname, dlen);
1242 }
1243
1244 static int audit_filter_user_rules(struct audit_krule *rule, int type,
1245 enum audit_state *state)
1246 {
1247 int i;
1248
1249 for (i = 0; i < rule->field_count; i++) {
1250 struct audit_field *f = &rule->fields[i];
1251 pid_t pid;
1252 int result = 0;
1253 u32 sid;
1254
1255 switch (f->type) {
1256 case AUDIT_PID:
1257 pid = task_pid_nr(current);
1258 result = audit_comparator(pid, f->op, f->val);
1259 break;
1260 case AUDIT_UID:
1261 result = audit_uid_comparator(current_uid(), f->op, f->uid);
1262 break;
1263 case AUDIT_GID:
1264 result = audit_gid_comparator(current_gid(), f->op, f->gid);
1265 break;
1266 case AUDIT_LOGINUID:
1267 result = audit_uid_comparator(audit_get_loginuid(current),
1268 f->op, f->uid);
1269 break;
1270 case AUDIT_LOGINUID_SET:
1271 result = audit_comparator(audit_loginuid_set(current),
1272 f->op, f->val);
1273 break;
1274 case AUDIT_MSGTYPE:
1275 result = audit_comparator(type, f->op, f->val);
1276 break;
1277 case AUDIT_SUBJ_USER:
1278 case AUDIT_SUBJ_ROLE:
1279 case AUDIT_SUBJ_TYPE:
1280 case AUDIT_SUBJ_SEN:
1281 case AUDIT_SUBJ_CLR:
1282 if (f->lsm_rule) {
1283 security_task_getsecid(current, &sid);
1284 result = security_audit_rule_match(sid,
1285 f->type,
1286 f->op,
1287 f->lsm_rule,
1288 NULL);
1289 }
1290 break;
1291 }
1292
1293 if (!result)
1294 return 0;
1295 }
1296 switch (rule->action) {
1297 case AUDIT_NEVER: *state = AUDIT_DISABLED; break;
1298 case AUDIT_ALWAYS: *state = AUDIT_RECORD_CONTEXT; break;
1299 }
1300 return 1;
1301 }
1302
1303 int audit_filter_user(int type)
1304 {
1305 enum audit_state state = AUDIT_DISABLED;
1306 struct audit_entry *e;
1307 int rc, ret;
1308
1309 ret = 1; /* Audit by default */
1310
1311 rcu_read_lock();
1312 list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_USER], list) {
1313 rc = audit_filter_user_rules(&e->rule, type, &state);
1314 if (rc) {
1315 if (rc > 0 && state == AUDIT_DISABLED)
1316 ret = 0;
1317 break;
1318 }
1319 }
1320 rcu_read_unlock();
1321
1322 return ret;
1323 }
1324
1325 int audit_filter_type(int type)
1326 {
1327 struct audit_entry *e;
1328 int result = 0;
1329
1330 rcu_read_lock();
1331 if (list_empty(&audit_filter_list[AUDIT_FILTER_TYPE]))
1332 goto unlock_and_return;
1333
1334 list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_TYPE],
1335 list) {
1336 int i;
1337 for (i = 0; i < e->rule.field_count; i++) {
1338 struct audit_field *f = &e->rule.fields[i];
1339 if (f->type == AUDIT_MSGTYPE) {
1340 result = audit_comparator(type, f->op, f->val);
1341 if (!result)
1342 break;
1343 }
1344 }
1345 if (result)
1346 goto unlock_and_return;
1347 }
1348 unlock_and_return:
1349 rcu_read_unlock();
1350 return result;
1351 }
1352
1353 static int update_lsm_rule(struct audit_krule *r)
1354 {
1355 struct audit_entry *entry = container_of(r, struct audit_entry, rule);
1356 struct audit_entry *nentry;
1357 int err = 0;
1358
1359 if (!security_audit_rule_known(r))
1360 return 0;
1361
1362 nentry = audit_dupe_rule(r);
1363 if (IS_ERR(nentry)) {
1364 /* save the first error encountered for the
1365 * return value */
1366 err = PTR_ERR(nentry);
1367 audit_panic("error updating LSM filters");
1368 if (r->watch)
1369 list_del(&r->rlist);
1370 list_del_rcu(&entry->list);
1371 list_del(&r->list);
1372 } else {
1373 if (r->watch || r->tree)
1374 list_replace_init(&r->rlist, &nentry->rule.rlist);
1375 list_replace_rcu(&entry->list, &nentry->list);
1376 list_replace(&r->list, &nentry->rule.list);
1377 }
1378 call_rcu(&entry->rcu, audit_free_rule_rcu);
1379
1380 return err;
1381 }
1382
1383 /* This function will re-initialize the lsm_rule field of all applicable rules.
1384 * It will traverse the filter lists serarching for rules that contain LSM
1385 * specific filter fields. When such a rule is found, it is copied, the
1386 * LSM field is re-initialized, and the old rule is replaced with the
1387 * updated rule. */
1388 int audit_update_lsm_rules(void)
1389 {
1390 struct audit_krule *r, *n;
1391 int i, err = 0;
1392
1393 /* audit_filter_mutex synchronizes the writers */
1394 mutex_lock(&audit_filter_mutex);
1395
1396 for (i = 0; i < AUDIT_NR_FILTERS; i++) {
1397 list_for_each_entry_safe(r, n, &audit_rules_list[i], list) {
1398 int res = update_lsm_rule(r);
1399 if (!err)
1400 err = res;
1401 }
1402 }
1403 mutex_unlock(&audit_filter_mutex);
1404
1405 return err;
1406 }