1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* auditfilter.c -- filtering of audit events
3 *
4 * Copyright 2003-2004 Red Hat, Inc.
5 * Copyright 2005 Hewlett-Packard Development Company, L.P.
6 * Copyright 2005 IBM Corporation
7 */
8
9 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
10
11 #include <linux/kernel.h>
12 #include <linux/audit.h>
13 #include <linux/kthread.h>
14 #include <linux/mutex.h>
15 #include <linux/fs.h>
16 #include <linux/namei.h>
17 #include <linux/netlink.h>
18 #include <linux/sched.h>
19 #include <linux/slab.h>
20 #include <linux/security.h>
21 #include <net/net_namespace.h>
22 #include <net/sock.h>
23 #include "audit.h"
24
25 /*
26 * Locking model:
27 *
28 * audit_filter_mutex:
29 * Synchronizes writes and blocking reads of audit's filterlist
30 * data. Rcu is used to traverse the filterlist and access
31 * contents of structs audit_entry, audit_watch and opaque
32 * LSM rules during filtering. If modified, these structures
33 * must be copied and replace their counterparts in the filterlist.
34 * An audit_parent struct is not accessed during filtering, so may
35 * be written directly provided audit_filter_mutex is held.
36 */
37
38 /* Audit filter lists, defined in <linux/audit.h> */
39 struct list_head audit_filter_list[AUDIT_NR_FILTERS] = {
40 LIST_HEAD_INIT(audit_filter_list[0]),
41 LIST_HEAD_INIT(audit_filter_list[1]),
42 LIST_HEAD_INIT(audit_filter_list[2]),
43 LIST_HEAD_INIT(audit_filter_list[3]),
44 LIST_HEAD_INIT(audit_filter_list[4]),
45 LIST_HEAD_INIT(audit_filter_list[5]),
46 LIST_HEAD_INIT(audit_filter_list[6]),
47 LIST_HEAD_INIT(audit_filter_list[7]),
48 #if AUDIT_NR_FILTERS != 8
49 #error Fix audit_filter_list initialiser
50 #endif
51 };
52 static struct list_head audit_rules_list[AUDIT_NR_FILTERS] = {
53 LIST_HEAD_INIT(audit_rules_list[0]),
54 LIST_HEAD_INIT(audit_rules_list[1]),
55 LIST_HEAD_INIT(audit_rules_list[2]),
56 LIST_HEAD_INIT(audit_rules_list[3]),
57 LIST_HEAD_INIT(audit_rules_list[4]),
58 LIST_HEAD_INIT(audit_rules_list[5]),
59 LIST_HEAD_INIT(audit_rules_list[6]),
60 LIST_HEAD_INIT(audit_rules_list[7]),
61 };
62
63 DEFINE_MUTEX(audit_filter_mutex);
64
audit_free_lsm_field(struct audit_field * f)65 static void audit_free_lsm_field(struct audit_field *f)
66 {
67 switch (f->type) {
68 case AUDIT_SUBJ_USER:
69 case AUDIT_SUBJ_ROLE:
70 case AUDIT_SUBJ_TYPE:
71 case AUDIT_SUBJ_SEN:
72 case AUDIT_SUBJ_CLR:
73 case AUDIT_OBJ_USER:
74 case AUDIT_OBJ_ROLE:
75 case AUDIT_OBJ_TYPE:
76 case AUDIT_OBJ_LEV_LOW:
77 case AUDIT_OBJ_LEV_HIGH:
78 kfree(f->lsm_str);
79 security_audit_rule_free(f->lsm_rule);
80 }
81 }
82
audit_free_rule(struct audit_entry * e)83 static inline void audit_free_rule(struct audit_entry *e)
84 {
85 int i;
86 struct audit_krule *erule = &e->rule;
87
88 /* some rules don't have associated watches */
89 if (erule->watch)
90 audit_put_watch(erule->watch);
91 if (erule->fields)
92 for (i = 0; i < erule->field_count; i++)
93 audit_free_lsm_field(&erule->fields[i]);
94 kfree(erule->fields);
95 kfree(erule->filterkey);
96 kfree(e);
97 }
98
audit_free_rule_rcu(struct rcu_head * head)99 void audit_free_rule_rcu(struct rcu_head *head)
100 {
101 struct audit_entry *e = container_of(head, struct audit_entry, rcu);
102 audit_free_rule(e);
103 }
104
105 /* Initialize an audit filterlist entry. */
audit_init_entry(u32 field_count)106 static inline struct audit_entry *audit_init_entry(u32 field_count)
107 {
108 struct audit_entry *entry;
109 struct audit_field *fields;
110
111 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
112 if (unlikely(!entry))
113 return NULL;
114
115 fields = kcalloc(field_count, sizeof(*fields), GFP_KERNEL);
116 if (unlikely(!fields)) {
117 kfree(entry);
118 return NULL;
119 }
120 entry->rule.fields = fields;
121
122 return entry;
123 }
124
125 /* Unpack a filter field's string representation from user-space
126 * buffer. */
audit_unpack_string(void ** bufp,size_t * remain,size_t len)127 char *audit_unpack_string(void **bufp, size_t *remain, size_t len)
128 {
129 char *str;
130
131 if (!*bufp || (len == 0) || (len > *remain))
132 return ERR_PTR(-EINVAL);
133
134 /* Of the currently implemented string fields, PATH_MAX
135 * defines the longest valid length.
136 */
137 if (len > PATH_MAX)
138 return ERR_PTR(-ENAMETOOLONG);
139
140 str = kmalloc(len + 1, GFP_KERNEL);
141 if (unlikely(!str))
142 return ERR_PTR(-ENOMEM);
143
144 memcpy(str, *bufp, len);
145 str[len] = 0;
146 *bufp += len;
147 *remain -= len;
148
149 return str;
150 }
151
152 /* Translate an inode field to kernel representation. */
audit_to_inode(struct audit_krule * krule,struct audit_field * f)153 static inline int audit_to_inode(struct audit_krule *krule,
154 struct audit_field *f)
155 {
156 if ((krule->listnr != AUDIT_FILTER_EXIT &&
157 krule->listnr != AUDIT_FILTER_URING_EXIT) ||
158 krule->inode_f || krule->watch || krule->tree ||
159 (f->op != Audit_equal && f->op != Audit_not_equal))
160 return -EINVAL;
161
162 krule->inode_f = f;
163 return 0;
164 }
165
166 static __u32 *classes[AUDIT_SYSCALL_CLASSES];
167
audit_register_class(int class,unsigned * list)168 int __init audit_register_class(int class, unsigned *list)
169 {
170 __u32 *p = kcalloc(AUDIT_BITMASK_SIZE, sizeof(__u32), GFP_KERNEL);
171 if (!p)
172 return -ENOMEM;
173 while (*list != ~0U) {
174 unsigned n = *list++;
175 if (n >= AUDIT_BITMASK_SIZE * 32 - AUDIT_SYSCALL_CLASSES) {
176 kfree(p);
177 return -EINVAL;
178 }
179 p[AUDIT_WORD(n)] |= AUDIT_BIT(n);
180 }
181 if (class >= AUDIT_SYSCALL_CLASSES || classes[class]) {
182 kfree(p);
183 return -EINVAL;
184 }
185 classes[class] = p;
186 return 0;
187 }
188
audit_match_class(int class,unsigned syscall)189 int audit_match_class(int class, unsigned syscall)
190 {
191 if (unlikely(syscall >= AUDIT_BITMASK_SIZE * 32))
192 return 0;
193 if (unlikely(class >= AUDIT_SYSCALL_CLASSES || !classes[class]))
194 return 0;
195 return classes[class][AUDIT_WORD(syscall)] & AUDIT_BIT(syscall);
196 }
197
198 #ifdef CONFIG_AUDITSYSCALL
audit_match_class_bits(int class,u32 * mask)199 static inline int audit_match_class_bits(int class, u32 *mask)
200 {
201 int i;
202
203 if (classes[class]) {
204 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
205 if (mask[i] & classes[class][i])
206 return 0;
207 }
208 return 1;
209 }
210
audit_match_signal(struct audit_entry * entry)211 static int audit_match_signal(struct audit_entry *entry)
212 {
213 struct audit_field *arch = entry->rule.arch_f;
214
215 if (!arch) {
216 /* When arch is unspecified, we must check both masks on biarch
217 * as syscall number alone is ambiguous. */
218 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
219 entry->rule.mask) &&
220 audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
221 entry->rule.mask));
222 }
223
224 switch(audit_classify_arch(arch->val)) {
225 case 0: /* native */
226 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
227 entry->rule.mask));
228 case 1: /* 32bit on biarch */
229 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
230 entry->rule.mask));
231 default:
232 return 1;
233 }
234 }
235 #endif
236
237 /* Common user-space to kernel rule translation. */
audit_to_entry_common(struct audit_rule_data * rule)238 static inline struct audit_entry *audit_to_entry_common(struct audit_rule_data *rule)
239 {
240 unsigned listnr;
241 struct audit_entry *entry;
242 int i, err;
243
244 err = -EINVAL;
245 listnr = rule->flags & ~AUDIT_FILTER_PREPEND;
246 switch(listnr) {
247 default:
248 goto exit_err;
249 #ifdef CONFIG_AUDITSYSCALL
250 case AUDIT_FILTER_ENTRY:
251 pr_err("AUDIT_FILTER_ENTRY is deprecated\n");
252 goto exit_err;
253 case AUDIT_FILTER_EXIT:
254 case AUDIT_FILTER_URING_EXIT:
255 case AUDIT_FILTER_TASK:
256 #endif
257 case AUDIT_FILTER_USER:
258 case AUDIT_FILTER_EXCLUDE:
259 case AUDIT_FILTER_FS:
260 ;
261 }
262 if (unlikely(rule->action == AUDIT_POSSIBLE)) {
263 pr_err("AUDIT_POSSIBLE is deprecated\n");
264 goto exit_err;
265 }
266 if (rule->action != AUDIT_NEVER && rule->action != AUDIT_ALWAYS)
267 goto exit_err;
268 if (rule->field_count > AUDIT_MAX_FIELDS)
269 goto exit_err;
270
271 err = -ENOMEM;
272 entry = audit_init_entry(rule->field_count);
273 if (!entry)
274 goto exit_err;
275
276 entry->rule.flags = rule->flags & AUDIT_FILTER_PREPEND;
277 entry->rule.listnr = listnr;
278 entry->rule.action = rule->action;
279 entry->rule.field_count = rule->field_count;
280
281 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
282 entry->rule.mask[i] = rule->mask[i];
283
284 for (i = 0; i < AUDIT_SYSCALL_CLASSES; i++) {
285 int bit = AUDIT_BITMASK_SIZE * 32 - i - 1;
286 __u32 *p = &entry->rule.mask[AUDIT_WORD(bit)];
287 __u32 *class;
288
289 if (!(*p & AUDIT_BIT(bit)))
290 continue;
291 *p &= ~AUDIT_BIT(bit);
292 class = classes[i];
293 if (class) {
294 int j;
295 for (j = 0; j < AUDIT_BITMASK_SIZE; j++)
296 entry->rule.mask[j] |= class[j];
297 }
298 }
299
300 return entry;
301
302 exit_err:
303 return ERR_PTR(err);
304 }
305
306 static u32 audit_ops[] =
307 {
308 [Audit_equal] = AUDIT_EQUAL,
309 [Audit_not_equal] = AUDIT_NOT_EQUAL,
310 [Audit_bitmask] = AUDIT_BIT_MASK,
311 [Audit_bittest] = AUDIT_BIT_TEST,
312 [Audit_lt] = AUDIT_LESS_THAN,
313 [Audit_gt] = AUDIT_GREATER_THAN,
314 [Audit_le] = AUDIT_LESS_THAN_OR_EQUAL,
315 [Audit_ge] = AUDIT_GREATER_THAN_OR_EQUAL,
316 };
317
audit_to_op(u32 op)318 static u32 audit_to_op(u32 op)
319 {
320 u32 n;
321 for (n = Audit_equal; n < Audit_bad && audit_ops[n] != op; n++)
322 ;
323 return n;
324 }
325
326 /* check if an audit field is valid */
audit_field_valid(struct audit_entry * entry,struct audit_field * f)327 static int audit_field_valid(struct audit_entry *entry, struct audit_field *f)
328 {
329 switch (f->type) {
330 case AUDIT_MSGTYPE:
331 if (entry->rule.listnr != AUDIT_FILTER_EXCLUDE &&
332 entry->rule.listnr != AUDIT_FILTER_USER)
333 return -EINVAL;
334 break;
335 case AUDIT_FSTYPE:
336 if (entry->rule.listnr != AUDIT_FILTER_FS)
337 return -EINVAL;
338 break;
339 case AUDIT_PERM:
340 if (entry->rule.listnr == AUDIT_FILTER_URING_EXIT)
341 return -EINVAL;
342 break;
343 }
344
345 switch (entry->rule.listnr) {
346 case AUDIT_FILTER_FS:
347 switch(f->type) {
348 case AUDIT_FSTYPE:
349 case AUDIT_FILTERKEY:
350 break;
351 default:
352 return -EINVAL;
353 }
354 }
355
356 /* Check for valid field type and op */
357 switch (f->type) {
358 case AUDIT_ARG0:
359 case AUDIT_ARG1:
360 case AUDIT_ARG2:
361 case AUDIT_ARG3:
362 case AUDIT_PERS: /* <uapi/linux/personality.h> */
363 case AUDIT_DEVMINOR:
364 /* all ops are valid */
365 break;
366 case AUDIT_UID:
367 case AUDIT_EUID:
368 case AUDIT_SUID:
369 case AUDIT_FSUID:
370 case AUDIT_LOGINUID:
371 case AUDIT_OBJ_UID:
372 case AUDIT_GID:
373 case AUDIT_EGID:
374 case AUDIT_SGID:
375 case AUDIT_FSGID:
376 case AUDIT_OBJ_GID:
377 case AUDIT_PID:
378 case AUDIT_MSGTYPE:
379 case AUDIT_PPID:
380 case AUDIT_DEVMAJOR:
381 case AUDIT_EXIT:
382 case AUDIT_SUCCESS:
383 case AUDIT_INODE:
384 case AUDIT_SESSIONID:
385 case AUDIT_SUBJ_SEN:
386 case AUDIT_SUBJ_CLR:
387 case AUDIT_OBJ_LEV_LOW:
388 case AUDIT_OBJ_LEV_HIGH:
389 case AUDIT_SADDR_FAM:
390 /* bit ops are only useful on syscall args */
391 if (f->op == Audit_bitmask || f->op == Audit_bittest)
392 return -EINVAL;
393 break;
394 case AUDIT_SUBJ_USER:
395 case AUDIT_SUBJ_ROLE:
396 case AUDIT_SUBJ_TYPE:
397 case AUDIT_OBJ_USER:
398 case AUDIT_OBJ_ROLE:
399 case AUDIT_OBJ_TYPE:
400 case AUDIT_WATCH:
401 case AUDIT_DIR:
402 case AUDIT_FILTERKEY:
403 case AUDIT_LOGINUID_SET:
404 case AUDIT_ARCH:
405 case AUDIT_FSTYPE:
406 case AUDIT_PERM:
407 case AUDIT_FILETYPE:
408 case AUDIT_FIELD_COMPARE:
409 case AUDIT_EXE:
410 /* only equal and not equal valid ops */
411 if (f->op != Audit_not_equal && f->op != Audit_equal)
412 return -EINVAL;
413 break;
414 default:
415 /* field not recognized */
416 return -EINVAL;
417 }
418
419 /* Check for select valid field values */
420 switch (f->type) {
421 case AUDIT_LOGINUID_SET:
422 if ((f->val != 0) && (f->val != 1))
423 return -EINVAL;
424 break;
425 case AUDIT_PERM:
426 if (f->val & ~15)
427 return -EINVAL;
428 break;
429 case AUDIT_FILETYPE:
430 if (f->val & ~S_IFMT)
431 return -EINVAL;
432 break;
433 case AUDIT_FIELD_COMPARE:
434 if (f->val > AUDIT_MAX_FIELD_COMPARE)
435 return -EINVAL;
436 break;
437 case AUDIT_SADDR_FAM:
438 if (f->val >= AF_MAX)
439 return -EINVAL;
440 break;
441 default:
442 break;
443 }
444
445 return 0;
446 }
447
448 /* Translate struct audit_rule_data to kernel's rule representation. */
audit_data_to_entry(struct audit_rule_data * data,size_t datasz)449 static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
450 size_t datasz)
451 {
452 int err = 0;
453 struct audit_entry *entry;
454 void *bufp;
455 size_t remain = datasz - sizeof(struct audit_rule_data);
456 int i;
457 char *str;
458 struct audit_fsnotify_mark *audit_mark;
459
460 entry = audit_to_entry_common(data);
461 if (IS_ERR(entry))
462 goto exit_nofree;
463
464 bufp = data->buf;
465 for (i = 0; i < data->field_count; i++) {
466 struct audit_field *f = &entry->rule.fields[i];
467 u32 f_val;
468
469 err = -EINVAL;
470
471 f->op = audit_to_op(data->fieldflags[i]);
472 if (f->op == Audit_bad)
473 goto exit_free;
474
475 f->type = data->fields[i];
476 f_val = data->values[i];
477
478 /* Support legacy tests for a valid loginuid */
479 if ((f->type == AUDIT_LOGINUID) && (f_val == AUDIT_UID_UNSET)) {
480 f->type = AUDIT_LOGINUID_SET;
481 f_val = 0;
482 entry->rule.pflags |= AUDIT_LOGINUID_LEGACY;
483 }
484
485 err = audit_field_valid(entry, f);
486 if (err)
487 goto exit_free;
488
489 err = -EINVAL;
490 switch (f->type) {
491 case AUDIT_LOGINUID:
492 case AUDIT_UID:
493 case AUDIT_EUID:
494 case AUDIT_SUID:
495 case AUDIT_FSUID:
496 case AUDIT_OBJ_UID:
497 f->uid = make_kuid(current_user_ns(), f_val);
498 if (!uid_valid(f->uid))
499 goto exit_free;
500 break;
501 case AUDIT_GID:
502 case AUDIT_EGID:
503 case AUDIT_SGID:
504 case AUDIT_FSGID:
505 case AUDIT_OBJ_GID:
506 f->gid = make_kgid(current_user_ns(), f_val);
507 if (!gid_valid(f->gid))
508 goto exit_free;
509 break;
510 case AUDIT_ARCH:
511 f->val = f_val;
512 entry->rule.arch_f = f;
513 break;
514 case AUDIT_SUBJ_USER:
515 case AUDIT_SUBJ_ROLE:
516 case AUDIT_SUBJ_TYPE:
517 case AUDIT_SUBJ_SEN:
518 case AUDIT_SUBJ_CLR:
519 case AUDIT_OBJ_USER:
520 case AUDIT_OBJ_ROLE:
521 case AUDIT_OBJ_TYPE:
522 case AUDIT_OBJ_LEV_LOW:
523 case AUDIT_OBJ_LEV_HIGH:
524 str = audit_unpack_string(&bufp, &remain, f_val);
525 if (IS_ERR(str)) {
526 err = PTR_ERR(str);
527 goto exit_free;
528 }
529 entry->rule.buflen += f_val;
530 f->lsm_str = str;
531 err = security_audit_rule_init(f->type, f->op, str,
532 (void **)&f->lsm_rule);
533 /* Keep currently invalid fields around in case they
534 * become valid after a policy reload. */
535 if (err == -EINVAL) {
536 pr_warn("audit rule for LSM \'%s\' is invalid\n",
537 str);
538 err = 0;
539 } else if (err)
540 goto exit_free;
541 break;
542 case AUDIT_WATCH:
543 str = audit_unpack_string(&bufp, &remain, f_val);
544 if (IS_ERR(str)) {
545 err = PTR_ERR(str);
546 goto exit_free;
547 }
548 err = audit_to_watch(&entry->rule, str, f_val, f->op);
549 if (err) {
550 kfree(str);
551 goto exit_free;
552 }
553 entry->rule.buflen += f_val;
554 break;
555 case AUDIT_DIR:
556 str = audit_unpack_string(&bufp, &remain, f_val);
557 if (IS_ERR(str)) {
558 err = PTR_ERR(str);
559 goto exit_free;
560 }
561 err = audit_make_tree(&entry->rule, str, f->op);
562 kfree(str);
563 if (err)
564 goto exit_free;
565 entry->rule.buflen += f_val;
566 break;
567 case AUDIT_INODE:
568 f->val = f_val;
569 err = audit_to_inode(&entry->rule, f);
570 if (err)
571 goto exit_free;
572 break;
573 case AUDIT_FILTERKEY:
574 if (entry->rule.filterkey || f_val > AUDIT_MAX_KEY_LEN)
575 goto exit_free;
576 str = audit_unpack_string(&bufp, &remain, f_val);
577 if (IS_ERR(str)) {
578 err = PTR_ERR(str);
579 goto exit_free;
580 }
581 entry->rule.buflen += f_val;
582 entry->rule.filterkey = str;
583 break;
584 case AUDIT_EXE:
585 if (entry->rule.exe || f_val > PATH_MAX)
586 goto exit_free;
587 str = audit_unpack_string(&bufp, &remain, f_val);
588 if (IS_ERR(str)) {
589 err = PTR_ERR(str);
590 goto exit_free;
591 }
592 audit_mark = audit_alloc_mark(&entry->rule, str, f_val);
593 if (IS_ERR(audit_mark)) {
594 kfree(str);
595 err = PTR_ERR(audit_mark);
596 goto exit_free;
597 }
598 entry->rule.buflen += f_val;
599 entry->rule.exe = audit_mark;
600 break;
601 default:
602 f->val = f_val;
603 break;
604 }
605 }
606
607 if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal)
608 entry->rule.inode_f = NULL;
609
610 exit_nofree:
611 return entry;
612
613 exit_free:
614 if (entry->rule.tree)
615 audit_put_tree(entry->rule.tree); /* that's the temporary one */
616 if (entry->rule.exe)
617 audit_remove_mark(entry->rule.exe); /* that's the template one */
618 audit_free_rule(entry);
619 return ERR_PTR(err);
620 }
621
622 /* Pack a filter field's string representation into data block. */
audit_pack_string(void ** bufp,const char * str)623 static inline size_t audit_pack_string(void **bufp, const char *str)
624 {
625 size_t len = strlen(str);
626
627 memcpy(*bufp, str, len);
628 *bufp += len;
629
630 return len;
631 }
632
633 /* Translate kernel rule representation to struct audit_rule_data. */
audit_krule_to_data(struct audit_krule * krule)634 static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule)
635 {
636 struct audit_rule_data *data;
637 void *bufp;
638 int i;
639
640 data = kmalloc(struct_size(data, buf, krule->buflen), GFP_KERNEL);
641 if (unlikely(!data))
642 return NULL;
643 memset(data, 0, sizeof(*data));
644
645 data->flags = krule->flags | krule->listnr;
646 data->action = krule->action;
647 data->field_count = krule->field_count;
648 bufp = data->buf;
649 for (i = 0; i < data->field_count; i++) {
650 struct audit_field *f = &krule->fields[i];
651
652 data->fields[i] = f->type;
653 data->fieldflags[i] = audit_ops[f->op];
654 switch(f->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 data->buflen += data->values[i] =
666 audit_pack_string(&bufp, f->lsm_str);
667 break;
668 case AUDIT_WATCH:
669 data->buflen += data->values[i] =
670 audit_pack_string(&bufp,
671 audit_watch_path(krule->watch));
672 break;
673 case AUDIT_DIR:
674 data->buflen += data->values[i] =
675 audit_pack_string(&bufp,
676 audit_tree_path(krule->tree));
677 break;
678 case AUDIT_FILTERKEY:
679 data->buflen += data->values[i] =
680 audit_pack_string(&bufp, krule->filterkey);
681 break;
682 case AUDIT_EXE:
683 data->buflen += data->values[i] =
684 audit_pack_string(&bufp, audit_mark_path(krule->exe));
685 break;
686 case AUDIT_LOGINUID_SET:
687 if (krule->pflags & AUDIT_LOGINUID_LEGACY && !f->val) {
688 data->fields[i] = AUDIT_LOGINUID;
689 data->values[i] = AUDIT_UID_UNSET;
690 break;
691 }
692 fallthrough; /* if set */
693 default:
694 data->values[i] = f->val;
695 }
696 }
697 for (i = 0; i < AUDIT_BITMASK_SIZE; i++) data->mask[i] = krule->mask[i];
698
699 return data;
700 }
701
702 /* Compare two rules in kernel format. Considered success if rules
703 * don't match. */
audit_compare_rule(struct audit_krule * a,struct audit_krule * b)704 static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
705 {
706 int i;
707
708 if (a->flags != b->flags ||
709 a->pflags != b->pflags ||
710 a->listnr != b->listnr ||
711 a->action != b->action ||
712 a->field_count != b->field_count)
713 return 1;
714
715 for (i = 0; i < a->field_count; i++) {
716 if (a->fields[i].type != b->fields[i].type ||
717 a->fields[i].op != b->fields[i].op)
718 return 1;
719
720 switch(a->fields[i].type) {
721 case AUDIT_SUBJ_USER:
722 case AUDIT_SUBJ_ROLE:
723 case AUDIT_SUBJ_TYPE:
724 case AUDIT_SUBJ_SEN:
725 case AUDIT_SUBJ_CLR:
726 case AUDIT_OBJ_USER:
727 case AUDIT_OBJ_ROLE:
728 case AUDIT_OBJ_TYPE:
729 case AUDIT_OBJ_LEV_LOW:
730 case AUDIT_OBJ_LEV_HIGH:
731 if (strcmp(a->fields[i].lsm_str, b->fields[i].lsm_str))
732 return 1;
733 break;
734 case AUDIT_WATCH:
735 if (strcmp(audit_watch_path(a->watch),
736 audit_watch_path(b->watch)))
737 return 1;
738 break;
739 case AUDIT_DIR:
740 if (strcmp(audit_tree_path(a->tree),
741 audit_tree_path(b->tree)))
742 return 1;
743 break;
744 case AUDIT_FILTERKEY:
745 /* both filterkeys exist based on above type compare */
746 if (strcmp(a->filterkey, b->filterkey))
747 return 1;
748 break;
749 case AUDIT_EXE:
750 /* both paths exist based on above type compare */
751 if (strcmp(audit_mark_path(a->exe),
752 audit_mark_path(b->exe)))
753 return 1;
754 break;
755 case AUDIT_UID:
756 case AUDIT_EUID:
757 case AUDIT_SUID:
758 case AUDIT_FSUID:
759 case AUDIT_LOGINUID:
760 case AUDIT_OBJ_UID:
761 if (!uid_eq(a->fields[i].uid, b->fields[i].uid))
762 return 1;
763 break;
764 case AUDIT_GID:
765 case AUDIT_EGID:
766 case AUDIT_SGID:
767 case AUDIT_FSGID:
768 case AUDIT_OBJ_GID:
769 if (!gid_eq(a->fields[i].gid, b->fields[i].gid))
770 return 1;
771 break;
772 default:
773 if (a->fields[i].val != b->fields[i].val)
774 return 1;
775 }
776 }
777
778 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
779 if (a->mask[i] != b->mask[i])
780 return 1;
781
782 return 0;
783 }
784
785 /* Duplicate LSM field information. The lsm_rule is opaque, so must be
786 * re-initialized. */
audit_dupe_lsm_field(struct audit_field * df,struct audit_field * sf)787 static inline int audit_dupe_lsm_field(struct audit_field *df,
788 struct audit_field *sf)
789 {
790 int ret = 0;
791 char *lsm_str;
792
793 /* our own copy of lsm_str */
794 lsm_str = kstrdup(sf->lsm_str, GFP_KERNEL);
795 if (unlikely(!lsm_str))
796 return -ENOMEM;
797 df->lsm_str = lsm_str;
798
799 /* our own (refreshed) copy of lsm_rule */
800 ret = security_audit_rule_init(df->type, df->op, df->lsm_str,
801 (void **)&df->lsm_rule);
802 /* Keep currently invalid fields around in case they
803 * become valid after a policy reload. */
804 if (ret == -EINVAL) {
805 pr_warn("audit rule for LSM \'%s\' is invalid\n",
806 df->lsm_str);
807 ret = 0;
808 }
809
810 return ret;
811 }
812
813 /* Duplicate an audit rule. This will be a deep copy with the exception
814 * of the watch - that pointer is carried over. The LSM specific fields
815 * will be updated in the copy. The point is to be able to replace the old
816 * rule with the new rule in the filterlist, then free the old rule.
817 * The rlist element is undefined; list manipulations are handled apart from
818 * the initial copy. */
audit_dupe_rule(struct audit_krule * old)819 struct audit_entry *audit_dupe_rule(struct audit_krule *old)
820 {
821 u32 fcount = old->field_count;
822 struct audit_entry *entry;
823 struct audit_krule *new;
824 char *fk;
825 int i, err = 0;
826
827 entry = audit_init_entry(fcount);
828 if (unlikely(!entry))
829 return ERR_PTR(-ENOMEM);
830
831 new = &entry->rule;
832 new->flags = old->flags;
833 new->pflags = old->pflags;
834 new->listnr = old->listnr;
835 new->action = old->action;
836 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
837 new->mask[i] = old->mask[i];
838 new->prio = old->prio;
839 new->buflen = old->buflen;
840 new->inode_f = old->inode_f;
841 new->field_count = old->field_count;
842
843 /*
844 * note that we are OK with not refcounting here; audit_match_tree()
845 * never dereferences tree and we can't get false positives there
846 * since we'd have to have rule gone from the list *and* removed
847 * before the chunks found by lookup had been allocated, i.e. before
848 * the beginning of list scan.
849 */
850 new->tree = old->tree;
851 memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount);
852
853 /* deep copy this information, updating the lsm_rule fields, because
854 * the originals will all be freed when the old rule is freed. */
855 for (i = 0; i < fcount; i++) {
856 switch (new->fields[i].type) {
857 case AUDIT_SUBJ_USER:
858 case AUDIT_SUBJ_ROLE:
859 case AUDIT_SUBJ_TYPE:
860 case AUDIT_SUBJ_SEN:
861 case AUDIT_SUBJ_CLR:
862 case AUDIT_OBJ_USER:
863 case AUDIT_OBJ_ROLE:
864 case AUDIT_OBJ_TYPE:
865 case AUDIT_OBJ_LEV_LOW:
866 case AUDIT_OBJ_LEV_HIGH:
867 err = audit_dupe_lsm_field(&new->fields[i],
868 &old->fields[i]);
869 break;
870 case AUDIT_FILTERKEY:
871 fk = kstrdup(old->filterkey, GFP_KERNEL);
872 if (unlikely(!fk))
873 err = -ENOMEM;
874 else
875 new->filterkey = fk;
876 break;
877 case AUDIT_EXE:
878 err = audit_dupe_exe(new, old);
879 break;
880 }
881 if (err) {
882 if (new->exe)
883 audit_remove_mark(new->exe);
884 audit_free_rule(entry);
885 return ERR_PTR(err);
886 }
887 }
888
889 if (old->watch) {
890 audit_get_watch(old->watch);
891 new->watch = old->watch;
892 }
893
894 return entry;
895 }
896
897 /* Find an existing audit rule.
898 * Caller must hold audit_filter_mutex to prevent stale rule data. */
audit_find_rule(struct audit_entry * entry,struct list_head ** p)899 static struct audit_entry *audit_find_rule(struct audit_entry *entry,
900 struct list_head **p)
901 {
902 struct audit_entry *e, *found = NULL;
903 struct list_head *list;
904 int h;
905
906 if (entry->rule.inode_f) {
907 h = audit_hash_ino(entry->rule.inode_f->val);
908 *p = list = &audit_inode_hash[h];
909 } else if (entry->rule.watch) {
910 /* we don't know the inode number, so must walk entire hash */
911 for (h = 0; h < AUDIT_INODE_BUCKETS; h++) {
912 list = &audit_inode_hash[h];
913 list_for_each_entry(e, list, list)
914 if (!audit_compare_rule(&entry->rule, &e->rule)) {
915 found = e;
916 goto out;
917 }
918 }
919 goto out;
920 } else {
921 *p = list = &audit_filter_list[entry->rule.listnr];
922 }
923
924 list_for_each_entry(e, list, list)
925 if (!audit_compare_rule(&entry->rule, &e->rule)) {
926 found = e;
927 goto out;
928 }
929
930 out:
931 return found;
932 }
933
934 static u64 prio_low = ~0ULL/2;
935 static u64 prio_high = ~0ULL/2 - 1;
936
937 /* Add rule to given filterlist if not a duplicate. */
audit_add_rule(struct audit_entry * entry)938 static inline int audit_add_rule(struct audit_entry *entry)
939 {
940 struct audit_entry *e;
941 struct audit_watch *watch = entry->rule.watch;
942 struct audit_tree *tree = entry->rule.tree;
943 struct list_head *list;
944 int err = 0;
945 #ifdef CONFIG_AUDITSYSCALL
946 int dont_count = 0;
947
948 /* If any of these, don't count towards total */
949 switch(entry->rule.listnr) {
950 case AUDIT_FILTER_USER:
951 case AUDIT_FILTER_EXCLUDE:
952 case AUDIT_FILTER_FS:
953 dont_count = 1;
954 }
955 #endif
956
957 mutex_lock(&audit_filter_mutex);
958 e = audit_find_rule(entry, &list);
959 if (e) {
960 mutex_unlock(&audit_filter_mutex);
961 err = -EEXIST;
962 /* normally audit_add_tree_rule() will free it on failure */
963 if (tree)
964 audit_put_tree(tree);
965 return err;
966 }
967
968 if (watch) {
969 /* audit_filter_mutex is dropped and re-taken during this call */
970 err = audit_add_watch(&entry->rule, &list);
971 if (err) {
972 mutex_unlock(&audit_filter_mutex);
973 /*
974 * normally audit_add_tree_rule() will free it
975 * on failure
976 */
977 if (tree)
978 audit_put_tree(tree);
979 return err;
980 }
981 }
982 if (tree) {
983 err = audit_add_tree_rule(&entry->rule);
984 if (err) {
985 mutex_unlock(&audit_filter_mutex);
986 return err;
987 }
988 }
989
990 entry->rule.prio = ~0ULL;
991 if (entry->rule.listnr == AUDIT_FILTER_EXIT ||
992 entry->rule.listnr == AUDIT_FILTER_URING_EXIT) {
993 if (entry->rule.flags & AUDIT_FILTER_PREPEND)
994 entry->rule.prio = ++prio_high;
995 else
996 entry->rule.prio = --prio_low;
997 }
998
999 if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
1000 list_add(&entry->rule.list,
1001 &audit_rules_list[entry->rule.listnr]);
1002 list_add_rcu(&entry->list, list);
1003 entry->rule.flags &= ~AUDIT_FILTER_PREPEND;
1004 } else {
1005 list_add_tail(&entry->rule.list,
1006 &audit_rules_list[entry->rule.listnr]);
1007 list_add_tail_rcu(&entry->list, list);
1008 }
1009 #ifdef CONFIG_AUDITSYSCALL
1010 if (!dont_count)
1011 audit_n_rules++;
1012
1013 if (!audit_match_signal(entry))
1014 audit_signals++;
1015 #endif
1016 mutex_unlock(&audit_filter_mutex);
1017
1018 return err;
1019 }
1020
1021 /* Remove an existing rule from filterlist. */
audit_del_rule(struct audit_entry * entry)1022 int audit_del_rule(struct audit_entry *entry)
1023 {
1024 struct audit_entry *e;
1025 struct audit_tree *tree = entry->rule.tree;
1026 struct list_head *list;
1027 int ret = 0;
1028 #ifdef CONFIG_AUDITSYSCALL
1029 int dont_count = 0;
1030
1031 /* If any of these, don't count towards total */
1032 switch(entry->rule.listnr) {
1033 case AUDIT_FILTER_USER:
1034 case AUDIT_FILTER_EXCLUDE:
1035 case AUDIT_FILTER_FS:
1036 dont_count = 1;
1037 }
1038 #endif
1039
1040 mutex_lock(&audit_filter_mutex);
1041 e = audit_find_rule(entry, &list);
1042 if (!e) {
1043 ret = -ENOENT;
1044 goto out;
1045 }
1046
1047 if (e->rule.watch)
1048 audit_remove_watch_rule(&e->rule);
1049
1050 if (e->rule.tree)
1051 audit_remove_tree_rule(&e->rule);
1052
1053 if (e->rule.exe)
1054 audit_remove_mark_rule(&e->rule);
1055
1056 #ifdef CONFIG_AUDITSYSCALL
1057 if (!dont_count)
1058 audit_n_rules--;
1059
1060 if (!audit_match_signal(entry))
1061 audit_signals--;
1062 #endif
1063
1064 list_del_rcu(&e->list);
1065 list_del(&e->rule.list);
1066 call_rcu(&e->rcu, audit_free_rule_rcu);
1067
1068 out:
1069 mutex_unlock(&audit_filter_mutex);
1070
1071 if (tree)
1072 audit_put_tree(tree); /* that's the temporary one */
1073
1074 return ret;
1075 }
1076
1077 /* List rules using struct audit_rule_data. */
audit_list_rules(int seq,struct sk_buff_head * q)1078 static void audit_list_rules(int seq, struct sk_buff_head *q)
1079 {
1080 struct sk_buff *skb;
1081 struct audit_krule *r;
1082 int i;
1083
1084 /* This is a blocking read, so use audit_filter_mutex instead of rcu
1085 * iterator to sync with list writers. */
1086 for (i=0; i<AUDIT_NR_FILTERS; i++) {
1087 list_for_each_entry(r, &audit_rules_list[i], list) {
1088 struct audit_rule_data *data;
1089
1090 data = audit_krule_to_data(r);
1091 if (unlikely(!data))
1092 break;
1093 skb = audit_make_reply(seq, AUDIT_LIST_RULES, 0, 1,
1094 data,
1095 struct_size(data, buf, data->buflen));
1096 if (skb)
1097 skb_queue_tail(q, skb);
1098 kfree(data);
1099 }
1100 }
1101 skb = audit_make_reply(seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);
1102 if (skb)
1103 skb_queue_tail(q, skb);
1104 }
1105
1106 /* Log rule additions and removals */
audit_log_rule_change(char * action,struct audit_krule * rule,int res)1107 static void audit_log_rule_change(char *action, struct audit_krule *rule, int res)
1108 {
1109 struct audit_buffer *ab;
1110
1111 if (!audit_enabled)
1112 return;
1113
1114 ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_CONFIG_CHANGE);
1115 if (!ab)
1116 return;
1117 audit_log_session_info(ab);
1118 audit_log_task_context(ab);
1119 audit_log_format(ab, " op=%s", action);
1120 audit_log_key(ab, rule->filterkey);
1121 audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
1122 audit_log_end(ab);
1123 }
1124
1125 /**
1126 * audit_rule_change - apply all rules to the specified message type
1127 * @type: audit message type
1128 * @seq: netlink audit message sequence (serial) number
1129 * @data: payload data
1130 * @datasz: size of payload data
1131 */
audit_rule_change(int type,int seq,void * data,size_t datasz)1132 int audit_rule_change(int type, int seq, void *data, size_t datasz)
1133 {
1134 int err = 0;
1135 struct audit_entry *entry;
1136
1137 switch (type) {
1138 case AUDIT_ADD_RULE:
1139 entry = audit_data_to_entry(data, datasz);
1140 if (IS_ERR(entry))
1141 return PTR_ERR(entry);
1142 err = audit_add_rule(entry);
1143 audit_log_rule_change("add_rule", &entry->rule, !err);
1144 break;
1145 case AUDIT_DEL_RULE:
1146 entry = audit_data_to_entry(data, datasz);
1147 if (IS_ERR(entry))
1148 return PTR_ERR(entry);
1149 err = audit_del_rule(entry);
1150 audit_log_rule_change("remove_rule", &entry->rule, !err);
1151 break;
1152 default:
1153 WARN_ON(1);
1154 return -EINVAL;
1155 }
1156
1157 if (err || type == AUDIT_DEL_RULE) {
1158 if (entry->rule.exe)
1159 audit_remove_mark(entry->rule.exe);
1160 audit_free_rule(entry);
1161 }
1162
1163 return err;
1164 }
1165
1166 /**
1167 * audit_list_rules_send - list the audit rules
1168 * @request_skb: skb of request we are replying to (used to target the reply)
1169 * @seq: netlink audit message sequence (serial) number
1170 */
audit_list_rules_send(struct sk_buff * request_skb,int seq)1171 int audit_list_rules_send(struct sk_buff *request_skb, int seq)
1172 {
1173 struct task_struct *tsk;
1174 struct audit_netlink_list *dest;
1175
1176 /* We can't just spew out the rules here because we might fill
1177 * the available socket buffer space and deadlock waiting for
1178 * auditctl to read from it... which isn't ever going to
1179 * happen if we're actually running in the context of auditctl
1180 * trying to _send_ the stuff */
1181
1182 dest = kmalloc(sizeof(*dest), GFP_KERNEL);
1183 if (!dest)
1184 return -ENOMEM;
1185 dest->net = get_net(sock_net(NETLINK_CB(request_skb).sk));
1186 dest->portid = NETLINK_CB(request_skb).portid;
1187 skb_queue_head_init(&dest->q);
1188
1189 mutex_lock(&audit_filter_mutex);
1190 audit_list_rules(seq, &dest->q);
1191 mutex_unlock(&audit_filter_mutex);
1192
1193 tsk = kthread_run(audit_send_list_thread, dest, "audit_send_list");
1194 if (IS_ERR(tsk)) {
1195 skb_queue_purge(&dest->q);
1196 put_net(dest->net);
1197 kfree(dest);
1198 return PTR_ERR(tsk);
1199 }
1200
1201 return 0;
1202 }
1203
audit_comparator(u32 left,u32 op,u32 right)1204 int audit_comparator(u32 left, u32 op, u32 right)
1205 {
1206 switch (op) {
1207 case Audit_equal:
1208 return (left == right);
1209 case Audit_not_equal:
1210 return (left != right);
1211 case Audit_lt:
1212 return (left < right);
1213 case Audit_le:
1214 return (left <= right);
1215 case Audit_gt:
1216 return (left > right);
1217 case Audit_ge:
1218 return (left >= right);
1219 case Audit_bitmask:
1220 return (left & right);
1221 case Audit_bittest:
1222 return ((left & right) == right);
1223 default:
1224 return 0;
1225 }
1226 }
1227
audit_uid_comparator(kuid_t left,u32 op,kuid_t right)1228 int audit_uid_comparator(kuid_t left, u32 op, kuid_t right)
1229 {
1230 switch (op) {
1231 case Audit_equal:
1232 return uid_eq(left, right);
1233 case Audit_not_equal:
1234 return !uid_eq(left, right);
1235 case Audit_lt:
1236 return uid_lt(left, right);
1237 case Audit_le:
1238 return uid_lte(left, right);
1239 case Audit_gt:
1240 return uid_gt(left, right);
1241 case Audit_ge:
1242 return uid_gte(left, right);
1243 case Audit_bitmask:
1244 case Audit_bittest:
1245 default:
1246 return 0;
1247 }
1248 }
1249
audit_gid_comparator(kgid_t left,u32 op,kgid_t right)1250 int audit_gid_comparator(kgid_t left, u32 op, kgid_t right)
1251 {
1252 switch (op) {
1253 case Audit_equal:
1254 return gid_eq(left, right);
1255 case Audit_not_equal:
1256 return !gid_eq(left, right);
1257 case Audit_lt:
1258 return gid_lt(left, right);
1259 case Audit_le:
1260 return gid_lte(left, right);
1261 case Audit_gt:
1262 return gid_gt(left, right);
1263 case Audit_ge:
1264 return gid_gte(left, right);
1265 case Audit_bitmask:
1266 case Audit_bittest:
1267 default:
1268 return 0;
1269 }
1270 }
1271
1272 /**
1273 * parent_len - find the length of the parent portion of a pathname
1274 * @path: pathname of which to determine length
1275 */
parent_len(const char * path)1276 int parent_len(const char *path)
1277 {
1278 int plen;
1279 const char *p;
1280
1281 plen = strlen(path);
1282
1283 if (plen == 0)
1284 return plen;
1285
1286 /* disregard trailing slashes */
1287 p = path + plen - 1;
1288 while ((*p == '/') && (p > path))
1289 p--;
1290
1291 /* walk backward until we find the next slash or hit beginning */
1292 while ((*p != '/') && (p > path))
1293 p--;
1294
1295 /* did we find a slash? Then increment to include it in path */
1296 if (*p == '/')
1297 p++;
1298
1299 return p - path;
1300 }
1301
1302 /**
1303 * audit_compare_dname_path - compare given dentry name with last component in
1304 * given path. Return of 0 indicates a match.
1305 * @dname: dentry name that we're comparing
1306 * @path: full pathname that we're comparing
1307 * @parentlen: length of the parent if known. Passing in AUDIT_NAME_FULL
1308 * here indicates that we must compute this value.
1309 */
audit_compare_dname_path(const struct qstr * dname,const char * path,int parentlen)1310 int audit_compare_dname_path(const struct qstr *dname, const char *path, int parentlen)
1311 {
1312 int dlen, pathlen;
1313 const char *p;
1314
1315 dlen = dname->len;
1316 pathlen = strlen(path);
1317 if (pathlen < dlen)
1318 return 1;
1319
1320 parentlen = parentlen == AUDIT_NAME_FULL ? parent_len(path) : parentlen;
1321 if (pathlen - parentlen != dlen)
1322 return 1;
1323
1324 p = path + parentlen;
1325
1326 return strncmp(p, dname->name, dlen);
1327 }
1328
audit_filter(int msgtype,unsigned int listtype)1329 int audit_filter(int msgtype, unsigned int listtype)
1330 {
1331 struct audit_entry *e;
1332 int ret = 1; /* Audit by default */
1333
1334 rcu_read_lock();
1335 list_for_each_entry_rcu(e, &audit_filter_list[listtype], list) {
1336 int i, result = 0;
1337
1338 for (i = 0; i < e->rule.field_count; i++) {
1339 struct audit_field *f = &e->rule.fields[i];
1340 pid_t pid;
1341 u32 sid;
1342
1343 switch (f->type) {
1344 case AUDIT_PID:
1345 pid = task_pid_nr(current);
1346 result = audit_comparator(pid, f->op, f->val);
1347 break;
1348 case AUDIT_UID:
1349 result = audit_uid_comparator(current_uid(), f->op, f->uid);
1350 break;
1351 case AUDIT_GID:
1352 result = audit_gid_comparator(current_gid(), f->op, f->gid);
1353 break;
1354 case AUDIT_LOGINUID:
1355 result = audit_uid_comparator(audit_get_loginuid(current),
1356 f->op, f->uid);
1357 break;
1358 case AUDIT_LOGINUID_SET:
1359 result = audit_comparator(audit_loginuid_set(current),
1360 f->op, f->val);
1361 break;
1362 case AUDIT_MSGTYPE:
1363 result = audit_comparator(msgtype, f->op, f->val);
1364 break;
1365 case AUDIT_SUBJ_USER:
1366 case AUDIT_SUBJ_ROLE:
1367 case AUDIT_SUBJ_TYPE:
1368 case AUDIT_SUBJ_SEN:
1369 case AUDIT_SUBJ_CLR:
1370 if (f->lsm_rule) {
1371 security_current_getsecid_subj(&sid);
1372 result = security_audit_rule_match(sid,
1373 f->type, f->op, f->lsm_rule);
1374 }
1375 break;
1376 case AUDIT_EXE:
1377 result = audit_exe_compare(current, e->rule.exe);
1378 if (f->op == Audit_not_equal)
1379 result = !result;
1380 break;
1381 default:
1382 goto unlock_and_return;
1383 }
1384 if (result < 0) /* error */
1385 goto unlock_and_return;
1386 if (!result)
1387 break;
1388 }
1389 if (result > 0) {
1390 if (e->rule.action == AUDIT_NEVER || listtype == AUDIT_FILTER_EXCLUDE)
1391 ret = 0;
1392 break;
1393 }
1394 }
1395 unlock_and_return:
1396 rcu_read_unlock();
1397 return ret;
1398 }
1399
update_lsm_rule(struct audit_krule * r)1400 static int update_lsm_rule(struct audit_krule *r)
1401 {
1402 struct audit_entry *entry = container_of(r, struct audit_entry, rule);
1403 struct audit_entry *nentry;
1404 int err = 0;
1405
1406 if (!security_audit_rule_known(r))
1407 return 0;
1408
1409 nentry = audit_dupe_rule(r);
1410 if (entry->rule.exe)
1411 audit_remove_mark(entry->rule.exe);
1412 if (IS_ERR(nentry)) {
1413 /* save the first error encountered for the
1414 * return value */
1415 err = PTR_ERR(nentry);
1416 audit_panic("error updating LSM filters");
1417 if (r->watch)
1418 list_del(&r->rlist);
1419 list_del_rcu(&entry->list);
1420 list_del(&r->list);
1421 } else {
1422 if (r->watch || r->tree)
1423 list_replace_init(&r->rlist, &nentry->rule.rlist);
1424 list_replace_rcu(&entry->list, &nentry->list);
1425 list_replace(&r->list, &nentry->rule.list);
1426 }
1427 call_rcu(&entry->rcu, audit_free_rule_rcu);
1428
1429 return err;
1430 }
1431
1432 /* This function will re-initialize the lsm_rule field of all applicable rules.
1433 * It will traverse the filter lists serarching for rules that contain LSM
1434 * specific filter fields. When such a rule is found, it is copied, the
1435 * LSM field is re-initialized, and the old rule is replaced with the
1436 * updated rule. */
audit_update_lsm_rules(void)1437 int audit_update_lsm_rules(void)
1438 {
1439 struct audit_krule *r, *n;
1440 int i, err = 0;
1441
1442 /* audit_filter_mutex synchronizes the writers */
1443 mutex_lock(&audit_filter_mutex);
1444
1445 for (i = 0; i < AUDIT_NR_FILTERS; i++) {
1446 list_for_each_entry_safe(r, n, &audit_rules_list[i], list) {
1447 int res = update_lsm_rule(r);
1448 if (!err)
1449 err = res;
1450 }
1451 }
1452 mutex_unlock(&audit_filter_mutex);
1453
1454 return err;
1455 }
1456