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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> */
39struct 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};
52static 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
63DEFINE_MUTEX(audit_filter_mutex);
64
65static 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
83static 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
99void 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. */
106static 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. */
127char *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. */
153static 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
166static __u32 *classes[AUDIT_SYSCALL_CLASSES];
167
168int __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
189int 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
199static 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
211static 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. */
238static 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
302exit_err:
303 return ERR_PTR(err);
304}
305
306static 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
318static 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 */
327static 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. */
449static 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
610exit_nofree:
611 return entry;
612
613exit_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. */
623static 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. */
634static 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. */
704static 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. */
787static 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. */
819struct 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. */
899static 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
930out:
931 return found;
932}
933
934static u64 prio_low = ~0ULL/2;
935static u64 prio_high = ~0ULL/2 - 1;
936
937/* Add rule to given filterlist if not a duplicate. */
938static 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. */
1022int 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
1068out:
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. */
1078static 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 */
1107static 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 */
1132int 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 */
1171int 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
1204int 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
1228int 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
1250int 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 */
1276int 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 */
1310int 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
1329int 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 }
1395unlock_and_return:
1396 rcu_read_unlock();
1397 return ret;
1398}
1399
1400static 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. */
1437int 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}
1/* auditfilter.c -- filtering of audit events
2 *
3 * Copyright 2003-2004 Red Hat, Inc.
4 * Copyright 2005 Hewlett-Packard Development Company, L.P.
5 * Copyright 2005 IBM Corporation
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 */
21
22#include <linux/kernel.h>
23#include <linux/audit.h>
24#include <linux/kthread.h>
25#include <linux/mutex.h>
26#include <linux/fs.h>
27#include <linux/namei.h>
28#include <linux/netlink.h>
29#include <linux/sched.h>
30#include <linux/slab.h>
31#include <linux/security.h>
32#include "audit.h"
33
34/*
35 * Locking model:
36 *
37 * audit_filter_mutex:
38 * Synchronizes writes and blocking reads of audit's filterlist
39 * data. Rcu is used to traverse the filterlist and access
40 * contents of structs audit_entry, audit_watch and opaque
41 * LSM rules during filtering. If modified, these structures
42 * must be copied and replace their counterparts in the filterlist.
43 * An audit_parent struct is not accessed during filtering, so may
44 * be written directly provided audit_filter_mutex is held.
45 */
46
47/* Audit filter lists, defined in <linux/audit.h> */
48struct list_head audit_filter_list[AUDIT_NR_FILTERS] = {
49 LIST_HEAD_INIT(audit_filter_list[0]),
50 LIST_HEAD_INIT(audit_filter_list[1]),
51 LIST_HEAD_INIT(audit_filter_list[2]),
52 LIST_HEAD_INIT(audit_filter_list[3]),
53 LIST_HEAD_INIT(audit_filter_list[4]),
54 LIST_HEAD_INIT(audit_filter_list[5]),
55#if AUDIT_NR_FILTERS != 6
56#error Fix audit_filter_list initialiser
57#endif
58};
59static struct list_head audit_rules_list[AUDIT_NR_FILTERS] = {
60 LIST_HEAD_INIT(audit_rules_list[0]),
61 LIST_HEAD_INIT(audit_rules_list[1]),
62 LIST_HEAD_INIT(audit_rules_list[2]),
63 LIST_HEAD_INIT(audit_rules_list[3]),
64 LIST_HEAD_INIT(audit_rules_list[4]),
65 LIST_HEAD_INIT(audit_rules_list[5]),
66};
67
68DEFINE_MUTEX(audit_filter_mutex);
69
70static inline void audit_free_rule(struct audit_entry *e)
71{
72 int i;
73 struct audit_krule *erule = &e->rule;
74
75 /* some rules don't have associated watches */
76 if (erule->watch)
77 audit_put_watch(erule->watch);
78 if (erule->fields)
79 for (i = 0; i < erule->field_count; i++) {
80 struct audit_field *f = &erule->fields[i];
81 kfree(f->lsm_str);
82 security_audit_rule_free(f->lsm_rule);
83 }
84 kfree(erule->fields);
85 kfree(erule->filterkey);
86 kfree(e);
87}
88
89void audit_free_rule_rcu(struct rcu_head *head)
90{
91 struct audit_entry *e = container_of(head, struct audit_entry, rcu);
92 audit_free_rule(e);
93}
94
95/* Initialize an audit filterlist entry. */
96static inline struct audit_entry *audit_init_entry(u32 field_count)
97{
98 struct audit_entry *entry;
99 struct audit_field *fields;
100
101 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
102 if (unlikely(!entry))
103 return NULL;
104
105 fields = kzalloc(sizeof(*fields) * field_count, GFP_KERNEL);
106 if (unlikely(!fields)) {
107 kfree(entry);
108 return NULL;
109 }
110 entry->rule.fields = fields;
111
112 return entry;
113}
114
115/* Unpack a filter field's string representation from user-space
116 * buffer. */
117char *audit_unpack_string(void **bufp, size_t *remain, size_t len)
118{
119 char *str;
120
121 if (!*bufp || (len == 0) || (len > *remain))
122 return ERR_PTR(-EINVAL);
123
124 /* Of the currently implemented string fields, PATH_MAX
125 * defines the longest valid length.
126 */
127 if (len > PATH_MAX)
128 return ERR_PTR(-ENAMETOOLONG);
129
130 str = kmalloc(len + 1, GFP_KERNEL);
131 if (unlikely(!str))
132 return ERR_PTR(-ENOMEM);
133
134 memcpy(str, *bufp, len);
135 str[len] = 0;
136 *bufp += len;
137 *remain -= len;
138
139 return str;
140}
141
142/* Translate an inode field to kernel respresentation. */
143static inline int audit_to_inode(struct audit_krule *krule,
144 struct audit_field *f)
145{
146 if (krule->listnr != AUDIT_FILTER_EXIT ||
147 krule->watch || krule->inode_f || krule->tree ||
148 (f->op != Audit_equal && f->op != Audit_not_equal))
149 return -EINVAL;
150
151 krule->inode_f = f;
152 return 0;
153}
154
155static __u32 *classes[AUDIT_SYSCALL_CLASSES];
156
157int __init audit_register_class(int class, unsigned *list)
158{
159 __u32 *p = kzalloc(AUDIT_BITMASK_SIZE * sizeof(__u32), GFP_KERNEL);
160 if (!p)
161 return -ENOMEM;
162 while (*list != ~0U) {
163 unsigned n = *list++;
164 if (n >= AUDIT_BITMASK_SIZE * 32 - AUDIT_SYSCALL_CLASSES) {
165 kfree(p);
166 return -EINVAL;
167 }
168 p[AUDIT_WORD(n)] |= AUDIT_BIT(n);
169 }
170 if (class >= AUDIT_SYSCALL_CLASSES || classes[class]) {
171 kfree(p);
172 return -EINVAL;
173 }
174 classes[class] = p;
175 return 0;
176}
177
178int audit_match_class(int class, unsigned syscall)
179{
180 if (unlikely(syscall >= AUDIT_BITMASK_SIZE * 32))
181 return 0;
182 if (unlikely(class >= AUDIT_SYSCALL_CLASSES || !classes[class]))
183 return 0;
184 return classes[class][AUDIT_WORD(syscall)] & AUDIT_BIT(syscall);
185}
186
187#ifdef CONFIG_AUDITSYSCALL
188static inline int audit_match_class_bits(int class, u32 *mask)
189{
190 int i;
191
192 if (classes[class]) {
193 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
194 if (mask[i] & classes[class][i])
195 return 0;
196 }
197 return 1;
198}
199
200static int audit_match_signal(struct audit_entry *entry)
201{
202 struct audit_field *arch = entry->rule.arch_f;
203
204 if (!arch) {
205 /* When arch is unspecified, we must check both masks on biarch
206 * as syscall number alone is ambiguous. */
207 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
208 entry->rule.mask) &&
209 audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
210 entry->rule.mask));
211 }
212
213 switch(audit_classify_arch(arch->val)) {
214 case 0: /* native */
215 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
216 entry->rule.mask));
217 case 1: /* 32bit on biarch */
218 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
219 entry->rule.mask));
220 default:
221 return 1;
222 }
223}
224#endif
225
226/* Common user-space to kernel rule translation. */
227static inline struct audit_entry *audit_to_entry_common(struct audit_rule *rule)
228{
229 unsigned listnr;
230 struct audit_entry *entry;
231 int i, err;
232
233 err = -EINVAL;
234 listnr = rule->flags & ~AUDIT_FILTER_PREPEND;
235 switch(listnr) {
236 default:
237 goto exit_err;
238#ifdef CONFIG_AUDITSYSCALL
239 case AUDIT_FILTER_ENTRY:
240 if (rule->action == AUDIT_ALWAYS)
241 goto exit_err;
242 case AUDIT_FILTER_EXIT:
243 case AUDIT_FILTER_TASK:
244#endif
245 case AUDIT_FILTER_USER:
246 case AUDIT_FILTER_TYPE:
247 ;
248 }
249 if (unlikely(rule->action == AUDIT_POSSIBLE)) {
250 printk(KERN_ERR "AUDIT_POSSIBLE is deprecated\n");
251 goto exit_err;
252 }
253 if (rule->action != AUDIT_NEVER && rule->action != AUDIT_ALWAYS)
254 goto exit_err;
255 if (rule->field_count > AUDIT_MAX_FIELDS)
256 goto exit_err;
257
258 err = -ENOMEM;
259 entry = audit_init_entry(rule->field_count);
260 if (!entry)
261 goto exit_err;
262
263 entry->rule.flags = rule->flags & AUDIT_FILTER_PREPEND;
264 entry->rule.listnr = listnr;
265 entry->rule.action = rule->action;
266 entry->rule.field_count = rule->field_count;
267
268 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
269 entry->rule.mask[i] = rule->mask[i];
270
271 for (i = 0; i < AUDIT_SYSCALL_CLASSES; i++) {
272 int bit = AUDIT_BITMASK_SIZE * 32 - i - 1;
273 __u32 *p = &entry->rule.mask[AUDIT_WORD(bit)];
274 __u32 *class;
275
276 if (!(*p & AUDIT_BIT(bit)))
277 continue;
278 *p &= ~AUDIT_BIT(bit);
279 class = classes[i];
280 if (class) {
281 int j;
282 for (j = 0; j < AUDIT_BITMASK_SIZE; j++)
283 entry->rule.mask[j] |= class[j];
284 }
285 }
286
287 return entry;
288
289exit_err:
290 return ERR_PTR(err);
291}
292
293static u32 audit_ops[] =
294{
295 [Audit_equal] = AUDIT_EQUAL,
296 [Audit_not_equal] = AUDIT_NOT_EQUAL,
297 [Audit_bitmask] = AUDIT_BIT_MASK,
298 [Audit_bittest] = AUDIT_BIT_TEST,
299 [Audit_lt] = AUDIT_LESS_THAN,
300 [Audit_gt] = AUDIT_GREATER_THAN,
301 [Audit_le] = AUDIT_LESS_THAN_OR_EQUAL,
302 [Audit_ge] = AUDIT_GREATER_THAN_OR_EQUAL,
303};
304
305static u32 audit_to_op(u32 op)
306{
307 u32 n;
308 for (n = Audit_equal; n < Audit_bad && audit_ops[n] != op; n++)
309 ;
310 return n;
311}
312
313
314/* Translate struct audit_rule to kernel's rule respresentation.
315 * Exists for backward compatibility with userspace. */
316static struct audit_entry *audit_rule_to_entry(struct audit_rule *rule)
317{
318 struct audit_entry *entry;
319 int err = 0;
320 int i;
321
322 entry = audit_to_entry_common(rule);
323 if (IS_ERR(entry))
324 goto exit_nofree;
325
326 for (i = 0; i < rule->field_count; i++) {
327 struct audit_field *f = &entry->rule.fields[i];
328 u32 n;
329
330 n = rule->fields[i] & (AUDIT_NEGATE|AUDIT_OPERATORS);
331
332 /* Support for legacy operators where
333 * AUDIT_NEGATE bit signifies != and otherwise assumes == */
334 if (n & AUDIT_NEGATE)
335 f->op = Audit_not_equal;
336 else if (!n)
337 f->op = Audit_equal;
338 else
339 f->op = audit_to_op(n);
340
341 entry->rule.vers_ops = (n & AUDIT_OPERATORS) ? 2 : 1;
342
343 f->type = rule->fields[i] & ~(AUDIT_NEGATE|AUDIT_OPERATORS);
344 f->val = rule->values[i];
345
346 err = -EINVAL;
347 if (f->op == Audit_bad)
348 goto exit_free;
349
350 switch(f->type) {
351 default:
352 goto exit_free;
353 case AUDIT_PID:
354 case AUDIT_UID:
355 case AUDIT_EUID:
356 case AUDIT_SUID:
357 case AUDIT_FSUID:
358 case AUDIT_GID:
359 case AUDIT_EGID:
360 case AUDIT_SGID:
361 case AUDIT_FSGID:
362 case AUDIT_LOGINUID:
363 case AUDIT_PERS:
364 case AUDIT_MSGTYPE:
365 case AUDIT_PPID:
366 case AUDIT_DEVMAJOR:
367 case AUDIT_DEVMINOR:
368 case AUDIT_EXIT:
369 case AUDIT_SUCCESS:
370 /* bit ops are only useful on syscall args */
371 if (f->op == Audit_bitmask || f->op == Audit_bittest)
372 goto exit_free;
373 break;
374 case AUDIT_ARG0:
375 case AUDIT_ARG1:
376 case AUDIT_ARG2:
377 case AUDIT_ARG3:
378 break;
379 /* arch is only allowed to be = or != */
380 case AUDIT_ARCH:
381 if (f->op != Audit_not_equal && f->op != Audit_equal)
382 goto exit_free;
383 entry->rule.arch_f = f;
384 break;
385 case AUDIT_PERM:
386 if (f->val & ~15)
387 goto exit_free;
388 break;
389 case AUDIT_FILETYPE:
390 if (f->val & ~S_IFMT)
391 goto exit_free;
392 break;
393 case AUDIT_INODE:
394 err = audit_to_inode(&entry->rule, f);
395 if (err)
396 goto exit_free;
397 break;
398 }
399 }
400
401 if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal)
402 entry->rule.inode_f = NULL;
403
404exit_nofree:
405 return entry;
406
407exit_free:
408 audit_free_rule(entry);
409 return ERR_PTR(err);
410}
411
412/* Translate struct audit_rule_data to kernel's rule respresentation. */
413static 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((struct audit_rule *)data);
424 if (IS_ERR(entry))
425 goto exit_nofree;
426
427 bufp = data->buf;
428 entry->rule.vers_ops = 2;
429 for (i = 0; i < data->field_count; i++) {
430 struct audit_field *f = &entry->rule.fields[i];
431
432 err = -EINVAL;
433
434 f->op = audit_to_op(data->fieldflags[i]);
435 if (f->op == Audit_bad)
436 goto exit_free;
437
438 f->type = data->fields[i];
439 f->val = data->values[i];
440 f->lsm_str = NULL;
441 f->lsm_rule = NULL;
442 switch(f->type) {
443 case AUDIT_PID:
444 case AUDIT_UID:
445 case AUDIT_EUID:
446 case AUDIT_SUID:
447 case AUDIT_FSUID:
448 case AUDIT_GID:
449 case AUDIT_EGID:
450 case AUDIT_SGID:
451 case AUDIT_FSGID:
452 case AUDIT_LOGINUID:
453 case AUDIT_PERS:
454 case AUDIT_MSGTYPE:
455 case AUDIT_PPID:
456 case AUDIT_DEVMAJOR:
457 case AUDIT_DEVMINOR:
458 case AUDIT_EXIT:
459 case AUDIT_SUCCESS:
460 case AUDIT_ARG0:
461 case AUDIT_ARG1:
462 case AUDIT_ARG2:
463 case AUDIT_ARG3:
464 case AUDIT_OBJ_UID:
465 case AUDIT_OBJ_GID:
466 break;
467 case AUDIT_ARCH:
468 entry->rule.arch_f = f;
469 break;
470 case AUDIT_SUBJ_USER:
471 case AUDIT_SUBJ_ROLE:
472 case AUDIT_SUBJ_TYPE:
473 case AUDIT_SUBJ_SEN:
474 case AUDIT_SUBJ_CLR:
475 case AUDIT_OBJ_USER:
476 case AUDIT_OBJ_ROLE:
477 case AUDIT_OBJ_TYPE:
478 case AUDIT_OBJ_LEV_LOW:
479 case AUDIT_OBJ_LEV_HIGH:
480 str = audit_unpack_string(&bufp, &remain, f->val);
481 if (IS_ERR(str))
482 goto exit_free;
483 entry->rule.buflen += f->val;
484
485 err = security_audit_rule_init(f->type, f->op, str,
486 (void **)&f->lsm_rule);
487 /* Keep currently invalid fields around in case they
488 * become valid after a policy reload. */
489 if (err == -EINVAL) {
490 printk(KERN_WARNING "audit rule for LSM "
491 "\'%s\' is invalid\n", str);
492 err = 0;
493 }
494 if (err) {
495 kfree(str);
496 goto exit_free;
497 } else
498 f->lsm_str = str;
499 break;
500 case AUDIT_WATCH:
501 str = audit_unpack_string(&bufp, &remain, f->val);
502 if (IS_ERR(str))
503 goto exit_free;
504 entry->rule.buflen += f->val;
505
506 err = audit_to_watch(&entry->rule, str, f->val, f->op);
507 if (err) {
508 kfree(str);
509 goto exit_free;
510 }
511 break;
512 case AUDIT_DIR:
513 str = audit_unpack_string(&bufp, &remain, f->val);
514 if (IS_ERR(str))
515 goto exit_free;
516 entry->rule.buflen += f->val;
517
518 err = audit_make_tree(&entry->rule, str, f->op);
519 kfree(str);
520 if (err)
521 goto exit_free;
522 break;
523 case AUDIT_INODE:
524 err = audit_to_inode(&entry->rule, f);
525 if (err)
526 goto exit_free;
527 break;
528 case AUDIT_FILTERKEY:
529 if (entry->rule.filterkey || f->val > AUDIT_MAX_KEY_LEN)
530 goto exit_free;
531 str = audit_unpack_string(&bufp, &remain, f->val);
532 if (IS_ERR(str))
533 goto exit_free;
534 entry->rule.buflen += f->val;
535 entry->rule.filterkey = str;
536 break;
537 case AUDIT_PERM:
538 if (f->val & ~15)
539 goto exit_free;
540 break;
541 case AUDIT_FILETYPE:
542 if (f->val & ~S_IFMT)
543 goto exit_free;
544 break;
545 case AUDIT_FIELD_COMPARE:
546 if (f->val > AUDIT_MAX_FIELD_COMPARE)
547 goto exit_free;
548 break;
549 default:
550 goto exit_free;
551 }
552 }
553
554 if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal)
555 entry->rule.inode_f = NULL;
556
557exit_nofree:
558 return entry;
559
560exit_free:
561 audit_free_rule(entry);
562 return ERR_PTR(err);
563}
564
565/* Pack a filter field's string representation into data block. */
566static inline size_t audit_pack_string(void **bufp, const char *str)
567{
568 size_t len = strlen(str);
569
570 memcpy(*bufp, str, len);
571 *bufp += len;
572
573 return len;
574}
575
576/* Translate kernel rule respresentation to struct audit_rule.
577 * Exists for backward compatibility with userspace. */
578static struct audit_rule *audit_krule_to_rule(struct audit_krule *krule)
579{
580 struct audit_rule *rule;
581 int i;
582
583 rule = kzalloc(sizeof(*rule), GFP_KERNEL);
584 if (unlikely(!rule))
585 return NULL;
586
587 rule->flags = krule->flags | krule->listnr;
588 rule->action = krule->action;
589 rule->field_count = krule->field_count;
590 for (i = 0; i < rule->field_count; i++) {
591 rule->values[i] = krule->fields[i].val;
592 rule->fields[i] = krule->fields[i].type;
593
594 if (krule->vers_ops == 1) {
595 if (krule->fields[i].op == Audit_not_equal)
596 rule->fields[i] |= AUDIT_NEGATE;
597 } else {
598 rule->fields[i] |= audit_ops[krule->fields[i].op];
599 }
600 }
601 for (i = 0; i < AUDIT_BITMASK_SIZE; i++) rule->mask[i] = krule->mask[i];
602
603 return rule;
604}
605
606/* Translate kernel rule respresentation to struct audit_rule_data. */
607static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule)
608{
609 struct audit_rule_data *data;
610 void *bufp;
611 int i;
612
613 data = kmalloc(sizeof(*data) + krule->buflen, GFP_KERNEL);
614 if (unlikely(!data))
615 return NULL;
616 memset(data, 0, sizeof(*data));
617
618 data->flags = krule->flags | krule->listnr;
619 data->action = krule->action;
620 data->field_count = krule->field_count;
621 bufp = data->buf;
622 for (i = 0; i < data->field_count; i++) {
623 struct audit_field *f = &krule->fields[i];
624
625 data->fields[i] = f->type;
626 data->fieldflags[i] = audit_ops[f->op];
627 switch(f->type) {
628 case AUDIT_SUBJ_USER:
629 case AUDIT_SUBJ_ROLE:
630 case AUDIT_SUBJ_TYPE:
631 case AUDIT_SUBJ_SEN:
632 case AUDIT_SUBJ_CLR:
633 case AUDIT_OBJ_USER:
634 case AUDIT_OBJ_ROLE:
635 case AUDIT_OBJ_TYPE:
636 case AUDIT_OBJ_LEV_LOW:
637 case AUDIT_OBJ_LEV_HIGH:
638 data->buflen += data->values[i] =
639 audit_pack_string(&bufp, f->lsm_str);
640 break;
641 case AUDIT_WATCH:
642 data->buflen += data->values[i] =
643 audit_pack_string(&bufp,
644 audit_watch_path(krule->watch));
645 break;
646 case AUDIT_DIR:
647 data->buflen += data->values[i] =
648 audit_pack_string(&bufp,
649 audit_tree_path(krule->tree));
650 break;
651 case AUDIT_FILTERKEY:
652 data->buflen += data->values[i] =
653 audit_pack_string(&bufp, krule->filterkey);
654 break;
655 default:
656 data->values[i] = f->val;
657 }
658 }
659 for (i = 0; i < AUDIT_BITMASK_SIZE; i++) data->mask[i] = krule->mask[i];
660
661 return data;
662}
663
664/* Compare two rules in kernel format. Considered success if rules
665 * don't match. */
666static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
667{
668 int i;
669
670 if (a->flags != b->flags ||
671 a->listnr != b->listnr ||
672 a->action != b->action ||
673 a->field_count != b->field_count)
674 return 1;
675
676 for (i = 0; i < a->field_count; i++) {
677 if (a->fields[i].type != b->fields[i].type ||
678 a->fields[i].op != b->fields[i].op)
679 return 1;
680
681 switch(a->fields[i].type) {
682 case AUDIT_SUBJ_USER:
683 case AUDIT_SUBJ_ROLE:
684 case AUDIT_SUBJ_TYPE:
685 case AUDIT_SUBJ_SEN:
686 case AUDIT_SUBJ_CLR:
687 case AUDIT_OBJ_USER:
688 case AUDIT_OBJ_ROLE:
689 case AUDIT_OBJ_TYPE:
690 case AUDIT_OBJ_LEV_LOW:
691 case AUDIT_OBJ_LEV_HIGH:
692 if (strcmp(a->fields[i].lsm_str, b->fields[i].lsm_str))
693 return 1;
694 break;
695 case AUDIT_WATCH:
696 if (strcmp(audit_watch_path(a->watch),
697 audit_watch_path(b->watch)))
698 return 1;
699 break;
700 case AUDIT_DIR:
701 if (strcmp(audit_tree_path(a->tree),
702 audit_tree_path(b->tree)))
703 return 1;
704 break;
705 case AUDIT_FILTERKEY:
706 /* both filterkeys exist based on above type compare */
707 if (strcmp(a->filterkey, b->filterkey))
708 return 1;
709 break;
710 default:
711 if (a->fields[i].val != b->fields[i].val)
712 return 1;
713 }
714 }
715
716 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
717 if (a->mask[i] != b->mask[i])
718 return 1;
719
720 return 0;
721}
722
723/* Duplicate LSM field information. The lsm_rule is opaque, so must be
724 * re-initialized. */
725static inline int audit_dupe_lsm_field(struct audit_field *df,
726 struct audit_field *sf)
727{
728 int ret = 0;
729 char *lsm_str;
730
731 /* our own copy of lsm_str */
732 lsm_str = kstrdup(sf->lsm_str, GFP_KERNEL);
733 if (unlikely(!lsm_str))
734 return -ENOMEM;
735 df->lsm_str = lsm_str;
736
737 /* our own (refreshed) copy of lsm_rule */
738 ret = security_audit_rule_init(df->type, df->op, df->lsm_str,
739 (void **)&df->lsm_rule);
740 /* Keep currently invalid fields around in case they
741 * become valid after a policy reload. */
742 if (ret == -EINVAL) {
743 printk(KERN_WARNING "audit rule for LSM \'%s\' is "
744 "invalid\n", df->lsm_str);
745 ret = 0;
746 }
747
748 return ret;
749}
750
751/* Duplicate an audit rule. This will be a deep copy with the exception
752 * of the watch - that pointer is carried over. The LSM specific fields
753 * will be updated in the copy. The point is to be able to replace the old
754 * rule with the new rule in the filterlist, then free the old rule.
755 * The rlist element is undefined; list manipulations are handled apart from
756 * the initial copy. */
757struct audit_entry *audit_dupe_rule(struct audit_krule *old)
758{
759 u32 fcount = old->field_count;
760 struct audit_entry *entry;
761 struct audit_krule *new;
762 char *fk;
763 int i, err = 0;
764
765 entry = audit_init_entry(fcount);
766 if (unlikely(!entry))
767 return ERR_PTR(-ENOMEM);
768
769 new = &entry->rule;
770 new->vers_ops = old->vers_ops;
771 new->flags = old->flags;
772 new->listnr = old->listnr;
773 new->action = old->action;
774 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
775 new->mask[i] = old->mask[i];
776 new->prio = old->prio;
777 new->buflen = old->buflen;
778 new->inode_f = old->inode_f;
779 new->field_count = old->field_count;
780
781 /*
782 * note that we are OK with not refcounting here; audit_match_tree()
783 * never dereferences tree and we can't get false positives there
784 * since we'd have to have rule gone from the list *and* removed
785 * before the chunks found by lookup had been allocated, i.e. before
786 * the beginning of list scan.
787 */
788 new->tree = old->tree;
789 memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount);
790
791 /* deep copy this information, updating the lsm_rule fields, because
792 * the originals will all be freed when the old rule is freed. */
793 for (i = 0; i < fcount; i++) {
794 switch (new->fields[i].type) {
795 case AUDIT_SUBJ_USER:
796 case AUDIT_SUBJ_ROLE:
797 case AUDIT_SUBJ_TYPE:
798 case AUDIT_SUBJ_SEN:
799 case AUDIT_SUBJ_CLR:
800 case AUDIT_OBJ_USER:
801 case AUDIT_OBJ_ROLE:
802 case AUDIT_OBJ_TYPE:
803 case AUDIT_OBJ_LEV_LOW:
804 case AUDIT_OBJ_LEV_HIGH:
805 err = audit_dupe_lsm_field(&new->fields[i],
806 &old->fields[i]);
807 break;
808 case AUDIT_FILTERKEY:
809 fk = kstrdup(old->filterkey, GFP_KERNEL);
810 if (unlikely(!fk))
811 err = -ENOMEM;
812 else
813 new->filterkey = fk;
814 }
815 if (err) {
816 audit_free_rule(entry);
817 return ERR_PTR(err);
818 }
819 }
820
821 if (old->watch) {
822 audit_get_watch(old->watch);
823 new->watch = old->watch;
824 }
825
826 return entry;
827}
828
829/* Find an existing audit rule.
830 * Caller must hold audit_filter_mutex to prevent stale rule data. */
831static struct audit_entry *audit_find_rule(struct audit_entry *entry,
832 struct list_head **p)
833{
834 struct audit_entry *e, *found = NULL;
835 struct list_head *list;
836 int h;
837
838 if (entry->rule.inode_f) {
839 h = audit_hash_ino(entry->rule.inode_f->val);
840 *p = list = &audit_inode_hash[h];
841 } else if (entry->rule.watch) {
842 /* we don't know the inode number, so must walk entire hash */
843 for (h = 0; h < AUDIT_INODE_BUCKETS; h++) {
844 list = &audit_inode_hash[h];
845 list_for_each_entry(e, list, list)
846 if (!audit_compare_rule(&entry->rule, &e->rule)) {
847 found = e;
848 goto out;
849 }
850 }
851 goto out;
852 } else {
853 *p = list = &audit_filter_list[entry->rule.listnr];
854 }
855
856 list_for_each_entry(e, list, list)
857 if (!audit_compare_rule(&entry->rule, &e->rule)) {
858 found = e;
859 goto out;
860 }
861
862out:
863 return found;
864}
865
866static u64 prio_low = ~0ULL/2;
867static u64 prio_high = ~0ULL/2 - 1;
868
869/* Add rule to given filterlist if not a duplicate. */
870static inline int audit_add_rule(struct audit_entry *entry)
871{
872 struct audit_entry *e;
873 struct audit_watch *watch = entry->rule.watch;
874 struct audit_tree *tree = entry->rule.tree;
875 struct list_head *list;
876 int err;
877#ifdef CONFIG_AUDITSYSCALL
878 int dont_count = 0;
879
880 /* If either of these, don't count towards total */
881 if (entry->rule.listnr == AUDIT_FILTER_USER ||
882 entry->rule.listnr == AUDIT_FILTER_TYPE)
883 dont_count = 1;
884#endif
885
886 mutex_lock(&audit_filter_mutex);
887 e = audit_find_rule(entry, &list);
888 if (e) {
889 mutex_unlock(&audit_filter_mutex);
890 err = -EEXIST;
891 /* normally audit_add_tree_rule() will free it on failure */
892 if (tree)
893 audit_put_tree(tree);
894 goto error;
895 }
896
897 if (watch) {
898 /* audit_filter_mutex is dropped and re-taken during this call */
899 err = audit_add_watch(&entry->rule, &list);
900 if (err) {
901 mutex_unlock(&audit_filter_mutex);
902 goto error;
903 }
904 }
905 if (tree) {
906 err = audit_add_tree_rule(&entry->rule);
907 if (err) {
908 mutex_unlock(&audit_filter_mutex);
909 goto error;
910 }
911 }
912
913 entry->rule.prio = ~0ULL;
914 if (entry->rule.listnr == AUDIT_FILTER_EXIT) {
915 if (entry->rule.flags & AUDIT_FILTER_PREPEND)
916 entry->rule.prio = ++prio_high;
917 else
918 entry->rule.prio = --prio_low;
919 }
920
921 if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
922 list_add(&entry->rule.list,
923 &audit_rules_list[entry->rule.listnr]);
924 list_add_rcu(&entry->list, list);
925 entry->rule.flags &= ~AUDIT_FILTER_PREPEND;
926 } else {
927 list_add_tail(&entry->rule.list,
928 &audit_rules_list[entry->rule.listnr]);
929 list_add_tail_rcu(&entry->list, list);
930 }
931#ifdef CONFIG_AUDITSYSCALL
932 if (!dont_count)
933 audit_n_rules++;
934
935 if (!audit_match_signal(entry))
936 audit_signals++;
937#endif
938 mutex_unlock(&audit_filter_mutex);
939
940 return 0;
941
942error:
943 if (watch)
944 audit_put_watch(watch); /* tmp watch, matches initial get */
945 return err;
946}
947
948/* Remove an existing rule from filterlist. */
949static inline int audit_del_rule(struct audit_entry *entry)
950{
951 struct audit_entry *e;
952 struct audit_watch *watch = entry->rule.watch;
953 struct audit_tree *tree = entry->rule.tree;
954 struct list_head *list;
955 int ret = 0;
956#ifdef CONFIG_AUDITSYSCALL
957 int dont_count = 0;
958
959 /* If either of these, don't count towards total */
960 if (entry->rule.listnr == AUDIT_FILTER_USER ||
961 entry->rule.listnr == AUDIT_FILTER_TYPE)
962 dont_count = 1;
963#endif
964
965 mutex_lock(&audit_filter_mutex);
966 e = audit_find_rule(entry, &list);
967 if (!e) {
968 mutex_unlock(&audit_filter_mutex);
969 ret = -ENOENT;
970 goto out;
971 }
972
973 if (e->rule.watch)
974 audit_remove_watch_rule(&e->rule);
975
976 if (e->rule.tree)
977 audit_remove_tree_rule(&e->rule);
978
979 list_del_rcu(&e->list);
980 list_del(&e->rule.list);
981 call_rcu(&e->rcu, audit_free_rule_rcu);
982
983#ifdef CONFIG_AUDITSYSCALL
984 if (!dont_count)
985 audit_n_rules--;
986
987 if (!audit_match_signal(entry))
988 audit_signals--;
989#endif
990 mutex_unlock(&audit_filter_mutex);
991
992out:
993 if (watch)
994 audit_put_watch(watch); /* match initial get */
995 if (tree)
996 audit_put_tree(tree); /* that's the temporary one */
997
998 return ret;
999}
1000
1001/* List rules using struct audit_rule. Exists for backward
1002 * compatibility with userspace. */
1003static void audit_list(int pid, int seq, struct sk_buff_head *q)
1004{
1005 struct sk_buff *skb;
1006 struct audit_krule *r;
1007 int i;
1008
1009 /* This is a blocking read, so use audit_filter_mutex instead of rcu
1010 * iterator to sync with list writers. */
1011 for (i=0; i<AUDIT_NR_FILTERS; i++) {
1012 list_for_each_entry(r, &audit_rules_list[i], list) {
1013 struct audit_rule *rule;
1014
1015 rule = audit_krule_to_rule(r);
1016 if (unlikely(!rule))
1017 break;
1018 skb = audit_make_reply(pid, seq, AUDIT_LIST, 0, 1,
1019 rule, sizeof(*rule));
1020 if (skb)
1021 skb_queue_tail(q, skb);
1022 kfree(rule);
1023 }
1024 }
1025 skb = audit_make_reply(pid, seq, AUDIT_LIST, 1, 1, NULL, 0);
1026 if (skb)
1027 skb_queue_tail(q, skb);
1028}
1029
1030/* List rules using struct audit_rule_data. */
1031static void audit_list_rules(int pid, int seq, struct sk_buff_head *q)
1032{
1033 struct sk_buff *skb;
1034 struct audit_krule *r;
1035 int i;
1036
1037 /* This is a blocking read, so use audit_filter_mutex instead of rcu
1038 * iterator to sync with list writers. */
1039 for (i=0; i<AUDIT_NR_FILTERS; i++) {
1040 list_for_each_entry(r, &audit_rules_list[i], list) {
1041 struct audit_rule_data *data;
1042
1043 data = audit_krule_to_data(r);
1044 if (unlikely(!data))
1045 break;
1046 skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 0, 1,
1047 data, sizeof(*data) + data->buflen);
1048 if (skb)
1049 skb_queue_tail(q, skb);
1050 kfree(data);
1051 }
1052 }
1053 skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);
1054 if (skb)
1055 skb_queue_tail(q, skb);
1056}
1057
1058/* Log rule additions and removals */
1059static void audit_log_rule_change(uid_t loginuid, u32 sessionid, u32 sid,
1060 char *action, struct audit_krule *rule,
1061 int res)
1062{
1063 struct audit_buffer *ab;
1064
1065 if (!audit_enabled)
1066 return;
1067
1068 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
1069 if (!ab)
1070 return;
1071 audit_log_format(ab, "auid=%u ses=%u", loginuid, sessionid);
1072 if (sid) {
1073 char *ctx = NULL;
1074 u32 len;
1075 if (security_secid_to_secctx(sid, &ctx, &len))
1076 audit_log_format(ab, " ssid=%u", sid);
1077 else {
1078 audit_log_format(ab, " subj=%s", ctx);
1079 security_release_secctx(ctx, len);
1080 }
1081 }
1082 audit_log_format(ab, " op=");
1083 audit_log_string(ab, action);
1084 audit_log_key(ab, rule->filterkey);
1085 audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
1086 audit_log_end(ab);
1087}
1088
1089/**
1090 * audit_receive_filter - apply all rules to the specified message type
1091 * @type: audit message type
1092 * @pid: target pid for netlink audit messages
1093 * @uid: target uid for netlink audit messages
1094 * @seq: netlink audit message sequence (serial) number
1095 * @data: payload data
1096 * @datasz: size of payload data
1097 * @loginuid: loginuid of sender
1098 * @sessionid: sessionid for netlink audit message
1099 * @sid: SE Linux Security ID of sender
1100 */
1101int audit_receive_filter(int type, int pid, int uid, int seq, void *data,
1102 size_t datasz, uid_t loginuid, u32 sessionid, u32 sid)
1103{
1104 struct task_struct *tsk;
1105 struct audit_netlink_list *dest;
1106 int err = 0;
1107 struct audit_entry *entry;
1108
1109 switch (type) {
1110 case AUDIT_LIST:
1111 case AUDIT_LIST_RULES:
1112 /* We can't just spew out the rules here because we might fill
1113 * the available socket buffer space and deadlock waiting for
1114 * auditctl to read from it... which isn't ever going to
1115 * happen if we're actually running in the context of auditctl
1116 * trying to _send_ the stuff */
1117
1118 dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL);
1119 if (!dest)
1120 return -ENOMEM;
1121 dest->pid = pid;
1122 skb_queue_head_init(&dest->q);
1123
1124 mutex_lock(&audit_filter_mutex);
1125 if (type == AUDIT_LIST)
1126 audit_list(pid, seq, &dest->q);
1127 else
1128 audit_list_rules(pid, seq, &dest->q);
1129 mutex_unlock(&audit_filter_mutex);
1130
1131 tsk = kthread_run(audit_send_list, dest, "audit_send_list");
1132 if (IS_ERR(tsk)) {
1133 skb_queue_purge(&dest->q);
1134 kfree(dest);
1135 err = PTR_ERR(tsk);
1136 }
1137 break;
1138 case AUDIT_ADD:
1139 case AUDIT_ADD_RULE:
1140 if (type == AUDIT_ADD)
1141 entry = audit_rule_to_entry(data);
1142 else
1143 entry = audit_data_to_entry(data, datasz);
1144 if (IS_ERR(entry))
1145 return PTR_ERR(entry);
1146
1147 err = audit_add_rule(entry);
1148 audit_log_rule_change(loginuid, sessionid, sid, "add rule",
1149 &entry->rule, !err);
1150
1151 if (err)
1152 audit_free_rule(entry);
1153 break;
1154 case AUDIT_DEL:
1155 case AUDIT_DEL_RULE:
1156 if (type == AUDIT_DEL)
1157 entry = audit_rule_to_entry(data);
1158 else
1159 entry = audit_data_to_entry(data, datasz);
1160 if (IS_ERR(entry))
1161 return PTR_ERR(entry);
1162
1163 err = audit_del_rule(entry);
1164 audit_log_rule_change(loginuid, sessionid, sid, "remove rule",
1165 &entry->rule, !err);
1166
1167 audit_free_rule(entry);
1168 break;
1169 default:
1170 return -EINVAL;
1171 }
1172
1173 return err;
1174}
1175
1176int audit_comparator(u32 left, u32 op, u32 right)
1177{
1178 switch (op) {
1179 case Audit_equal:
1180 return (left == right);
1181 case Audit_not_equal:
1182 return (left != right);
1183 case Audit_lt:
1184 return (left < right);
1185 case Audit_le:
1186 return (left <= right);
1187 case Audit_gt:
1188 return (left > right);
1189 case Audit_ge:
1190 return (left >= right);
1191 case Audit_bitmask:
1192 return (left & right);
1193 case Audit_bittest:
1194 return ((left & right) == right);
1195 default:
1196 BUG();
1197 return 0;
1198 }
1199}
1200
1201/* Compare given dentry name with last component in given path,
1202 * return of 0 indicates a match. */
1203int audit_compare_dname_path(const char *dname, const char *path,
1204 int *dirlen)
1205{
1206 int dlen, plen;
1207 const char *p;
1208
1209 if (!dname || !path)
1210 return 1;
1211
1212 dlen = strlen(dname);
1213 plen = strlen(path);
1214 if (plen < dlen)
1215 return 1;
1216
1217 /* disregard trailing slashes */
1218 p = path + plen - 1;
1219 while ((*p == '/') && (p > path))
1220 p--;
1221
1222 /* find last path component */
1223 p = p - dlen + 1;
1224 if (p < path)
1225 return 1;
1226 else if (p > path) {
1227 if (*--p != '/')
1228 return 1;
1229 else
1230 p++;
1231 }
1232
1233 /* return length of path's directory component */
1234 if (dirlen)
1235 *dirlen = p - path;
1236 return strncmp(p, dname, dlen);
1237}
1238
1239static int audit_filter_user_rules(struct netlink_skb_parms *cb,
1240 struct audit_krule *rule,
1241 enum audit_state *state)
1242{
1243 int i;
1244
1245 for (i = 0; i < rule->field_count; i++) {
1246 struct audit_field *f = &rule->fields[i];
1247 int result = 0;
1248 u32 sid;
1249
1250 switch (f->type) {
1251 case AUDIT_PID:
1252 result = audit_comparator(cb->creds.pid, f->op, f->val);
1253 break;
1254 case AUDIT_UID:
1255 result = audit_comparator(cb->creds.uid, f->op, f->val);
1256 break;
1257 case AUDIT_GID:
1258 result = audit_comparator(cb->creds.gid, f->op, f->val);
1259 break;
1260 case AUDIT_LOGINUID:
1261 result = audit_comparator(audit_get_loginuid(current),
1262 f->op, f->val);
1263 break;
1264 case AUDIT_SUBJ_USER:
1265 case AUDIT_SUBJ_ROLE:
1266 case AUDIT_SUBJ_TYPE:
1267 case AUDIT_SUBJ_SEN:
1268 case AUDIT_SUBJ_CLR:
1269 if (f->lsm_rule) {
1270 security_task_getsecid(current, &sid);
1271 result = security_audit_rule_match(sid,
1272 f->type,
1273 f->op,
1274 f->lsm_rule,
1275 NULL);
1276 }
1277 break;
1278 }
1279
1280 if (!result)
1281 return 0;
1282 }
1283 switch (rule->action) {
1284 case AUDIT_NEVER: *state = AUDIT_DISABLED; break;
1285 case AUDIT_ALWAYS: *state = AUDIT_RECORD_CONTEXT; break;
1286 }
1287 return 1;
1288}
1289
1290int audit_filter_user(struct netlink_skb_parms *cb)
1291{
1292 enum audit_state state = AUDIT_DISABLED;
1293 struct audit_entry *e;
1294 int ret = 1;
1295
1296 rcu_read_lock();
1297 list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_USER], list) {
1298 if (audit_filter_user_rules(cb, &e->rule, &state)) {
1299 if (state == AUDIT_DISABLED)
1300 ret = 0;
1301 break;
1302 }
1303 }
1304 rcu_read_unlock();
1305
1306 return ret; /* Audit by default */
1307}
1308
1309int audit_filter_type(int type)
1310{
1311 struct audit_entry *e;
1312 int result = 0;
1313
1314 rcu_read_lock();
1315 if (list_empty(&audit_filter_list[AUDIT_FILTER_TYPE]))
1316 goto unlock_and_return;
1317
1318 list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_TYPE],
1319 list) {
1320 int i;
1321 for (i = 0; i < e->rule.field_count; i++) {
1322 struct audit_field *f = &e->rule.fields[i];
1323 if (f->type == AUDIT_MSGTYPE) {
1324 result = audit_comparator(type, f->op, f->val);
1325 if (!result)
1326 break;
1327 }
1328 }
1329 if (result)
1330 goto unlock_and_return;
1331 }
1332unlock_and_return:
1333 rcu_read_unlock();
1334 return result;
1335}
1336
1337static int update_lsm_rule(struct audit_krule *r)
1338{
1339 struct audit_entry *entry = container_of(r, struct audit_entry, rule);
1340 struct audit_entry *nentry;
1341 int err = 0;
1342
1343 if (!security_audit_rule_known(r))
1344 return 0;
1345
1346 nentry = audit_dupe_rule(r);
1347 if (IS_ERR(nentry)) {
1348 /* save the first error encountered for the
1349 * return value */
1350 err = PTR_ERR(nentry);
1351 audit_panic("error updating LSM filters");
1352 if (r->watch)
1353 list_del(&r->rlist);
1354 list_del_rcu(&entry->list);
1355 list_del(&r->list);
1356 } else {
1357 if (r->watch || r->tree)
1358 list_replace_init(&r->rlist, &nentry->rule.rlist);
1359 list_replace_rcu(&entry->list, &nentry->list);
1360 list_replace(&r->list, &nentry->rule.list);
1361 }
1362 call_rcu(&entry->rcu, audit_free_rule_rcu);
1363
1364 return err;
1365}
1366
1367/* This function will re-initialize the lsm_rule field of all applicable rules.
1368 * It will traverse the filter lists serarching for rules that contain LSM
1369 * specific filter fields. When such a rule is found, it is copied, the
1370 * LSM field is re-initialized, and the old rule is replaced with the
1371 * updated rule. */
1372int audit_update_lsm_rules(void)
1373{
1374 struct audit_krule *r, *n;
1375 int i, err = 0;
1376
1377 /* audit_filter_mutex synchronizes the writers */
1378 mutex_lock(&audit_filter_mutex);
1379
1380 for (i = 0; i < AUDIT_NR_FILTERS; i++) {
1381 list_for_each_entry_safe(r, n, &audit_rules_list[i], list) {
1382 int res = update_lsm_rule(r);
1383 if (!err)
1384 err = res;
1385 }
1386 }
1387 mutex_unlock(&audit_filter_mutex);
1388
1389 return err;
1390}