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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++)
698 data->mask[i] = krule->mask[i];
699
700 return data;
701}
702
703/* Compare two rules in kernel format. Considered success if rules
704 * don't match. */
705static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
706{
707 int i;
708
709 if (a->flags != b->flags ||
710 a->pflags != b->pflags ||
711 a->listnr != b->listnr ||
712 a->action != b->action ||
713 a->field_count != b->field_count)
714 return 1;
715
716 for (i = 0; i < a->field_count; i++) {
717 if (a->fields[i].type != b->fields[i].type ||
718 a->fields[i].op != b->fields[i].op)
719 return 1;
720
721 switch (a->fields[i].type) {
722 case AUDIT_SUBJ_USER:
723 case AUDIT_SUBJ_ROLE:
724 case AUDIT_SUBJ_TYPE:
725 case AUDIT_SUBJ_SEN:
726 case AUDIT_SUBJ_CLR:
727 case AUDIT_OBJ_USER:
728 case AUDIT_OBJ_ROLE:
729 case AUDIT_OBJ_TYPE:
730 case AUDIT_OBJ_LEV_LOW:
731 case AUDIT_OBJ_LEV_HIGH:
732 if (strcmp(a->fields[i].lsm_str, b->fields[i].lsm_str))
733 return 1;
734 break;
735 case AUDIT_WATCH:
736 if (strcmp(audit_watch_path(a->watch),
737 audit_watch_path(b->watch)))
738 return 1;
739 break;
740 case AUDIT_DIR:
741 if (strcmp(audit_tree_path(a->tree),
742 audit_tree_path(b->tree)))
743 return 1;
744 break;
745 case AUDIT_FILTERKEY:
746 /* both filterkeys exist based on above type compare */
747 if (strcmp(a->filterkey, b->filterkey))
748 return 1;
749 break;
750 case AUDIT_EXE:
751 /* both paths exist based on above type compare */
752 if (strcmp(audit_mark_path(a->exe),
753 audit_mark_path(b->exe)))
754 return 1;
755 break;
756 case AUDIT_UID:
757 case AUDIT_EUID:
758 case AUDIT_SUID:
759 case AUDIT_FSUID:
760 case AUDIT_LOGINUID:
761 case AUDIT_OBJ_UID:
762 if (!uid_eq(a->fields[i].uid, b->fields[i].uid))
763 return 1;
764 break;
765 case AUDIT_GID:
766 case AUDIT_EGID:
767 case AUDIT_SGID:
768 case AUDIT_FSGID:
769 case AUDIT_OBJ_GID:
770 if (!gid_eq(a->fields[i].gid, b->fields[i].gid))
771 return 1;
772 break;
773 default:
774 if (a->fields[i].val != b->fields[i].val)
775 return 1;
776 }
777 }
778
779 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
780 if (a->mask[i] != b->mask[i])
781 return 1;
782
783 return 0;
784}
785
786/* Duplicate LSM field information. The lsm_rule is opaque, so must be
787 * re-initialized. */
788static inline int audit_dupe_lsm_field(struct audit_field *df,
789 struct audit_field *sf)
790{
791 int ret = 0;
792 char *lsm_str;
793
794 /* our own copy of lsm_str */
795 lsm_str = kstrdup(sf->lsm_str, GFP_KERNEL);
796 if (unlikely(!lsm_str))
797 return -ENOMEM;
798 df->lsm_str = lsm_str;
799
800 /* our own (refreshed) copy of lsm_rule */
801 ret = security_audit_rule_init(df->type, df->op, df->lsm_str,
802 (void **)&df->lsm_rule);
803 /* Keep currently invalid fields around in case they
804 * become valid after a policy reload. */
805 if (ret == -EINVAL) {
806 pr_warn("audit rule for LSM \'%s\' is invalid\n",
807 df->lsm_str);
808 ret = 0;
809 }
810
811 return ret;
812}
813
814/* Duplicate an audit rule. This will be a deep copy with the exception
815 * of the watch - that pointer is carried over. The LSM specific fields
816 * will be updated in the copy. The point is to be able to replace the old
817 * rule with the new rule in the filterlist, then free the old rule.
818 * The rlist element is undefined; list manipulations are handled apart from
819 * the initial copy. */
820struct audit_entry *audit_dupe_rule(struct audit_krule *old)
821{
822 u32 fcount = old->field_count;
823 struct audit_entry *entry;
824 struct audit_krule *new;
825 char *fk;
826 int i, err = 0;
827
828 entry = audit_init_entry(fcount);
829 if (unlikely(!entry))
830 return ERR_PTR(-ENOMEM);
831
832 new = &entry->rule;
833 new->flags = old->flags;
834 new->pflags = old->pflags;
835 new->listnr = old->listnr;
836 new->action = old->action;
837 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
838 new->mask[i] = old->mask[i];
839 new->prio = old->prio;
840 new->buflen = old->buflen;
841 new->inode_f = old->inode_f;
842 new->field_count = old->field_count;
843
844 /*
845 * note that we are OK with not refcounting here; audit_match_tree()
846 * never dereferences tree and we can't get false positives there
847 * since we'd have to have rule gone from the list *and* removed
848 * before the chunks found by lookup had been allocated, i.e. before
849 * the beginning of list scan.
850 */
851 new->tree = old->tree;
852 memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount);
853
854 /* deep copy this information, updating the lsm_rule fields, because
855 * the originals will all be freed when the old rule is freed. */
856 for (i = 0; i < fcount; i++) {
857 switch (new->fields[i].type) {
858 case AUDIT_SUBJ_USER:
859 case AUDIT_SUBJ_ROLE:
860 case AUDIT_SUBJ_TYPE:
861 case AUDIT_SUBJ_SEN:
862 case AUDIT_SUBJ_CLR:
863 case AUDIT_OBJ_USER:
864 case AUDIT_OBJ_ROLE:
865 case AUDIT_OBJ_TYPE:
866 case AUDIT_OBJ_LEV_LOW:
867 case AUDIT_OBJ_LEV_HIGH:
868 err = audit_dupe_lsm_field(&new->fields[i],
869 &old->fields[i]);
870 break;
871 case AUDIT_FILTERKEY:
872 fk = kstrdup(old->filterkey, GFP_KERNEL);
873 if (unlikely(!fk))
874 err = -ENOMEM;
875 else
876 new->filterkey = fk;
877 break;
878 case AUDIT_EXE:
879 err = audit_dupe_exe(new, old);
880 break;
881 }
882 if (err) {
883 if (new->exe)
884 audit_remove_mark(new->exe);
885 audit_free_rule(entry);
886 return ERR_PTR(err);
887 }
888 }
889
890 if (old->watch) {
891 audit_get_watch(old->watch);
892 new->watch = old->watch;
893 }
894
895 return entry;
896}
897
898/* Find an existing audit rule.
899 * Caller must hold audit_filter_mutex to prevent stale rule data. */
900static struct audit_entry *audit_find_rule(struct audit_entry *entry,
901 struct list_head **p)
902{
903 struct audit_entry *e, *found = NULL;
904 struct list_head *list;
905 int h;
906
907 if (entry->rule.inode_f) {
908 h = audit_hash_ino(entry->rule.inode_f->val);
909 *p = list = &audit_inode_hash[h];
910 } else if (entry->rule.watch) {
911 /* we don't know the inode number, so must walk entire hash */
912 for (h = 0; h < AUDIT_INODE_BUCKETS; h++) {
913 list = &audit_inode_hash[h];
914 list_for_each_entry(e, list, list)
915 if (!audit_compare_rule(&entry->rule, &e->rule)) {
916 found = e;
917 goto out;
918 }
919 }
920 goto out;
921 } else {
922 *p = list = &audit_filter_list[entry->rule.listnr];
923 }
924
925 list_for_each_entry(e, list, list)
926 if (!audit_compare_rule(&entry->rule, &e->rule)) {
927 found = e;
928 goto out;
929 }
930
931out:
932 return found;
933}
934
935static u64 prio_low = ~0ULL/2;
936static u64 prio_high = ~0ULL/2 - 1;
937
938/* Add rule to given filterlist if not a duplicate. */
939static inline int audit_add_rule(struct audit_entry *entry)
940{
941 struct audit_entry *e;
942 struct audit_watch *watch = entry->rule.watch;
943 struct audit_tree *tree = entry->rule.tree;
944 struct list_head *list;
945 int err = 0;
946#ifdef CONFIG_AUDITSYSCALL
947 int dont_count = 0;
948
949 /* If any of these, don't count towards total */
950 switch (entry->rule.listnr) {
951 case AUDIT_FILTER_USER:
952 case AUDIT_FILTER_EXCLUDE:
953 case AUDIT_FILTER_FS:
954 dont_count = 1;
955 }
956#endif
957
958 mutex_lock(&audit_filter_mutex);
959 e = audit_find_rule(entry, &list);
960 if (e) {
961 mutex_unlock(&audit_filter_mutex);
962 err = -EEXIST;
963 /* normally audit_add_tree_rule() will free it on failure */
964 if (tree)
965 audit_put_tree(tree);
966 return err;
967 }
968
969 if (watch) {
970 /* audit_filter_mutex is dropped and re-taken during this call */
971 err = audit_add_watch(&entry->rule, &list);
972 if (err) {
973 mutex_unlock(&audit_filter_mutex);
974 /*
975 * normally audit_add_tree_rule() will free it
976 * on failure
977 */
978 if (tree)
979 audit_put_tree(tree);
980 return err;
981 }
982 }
983 if (tree) {
984 err = audit_add_tree_rule(&entry->rule);
985 if (err) {
986 mutex_unlock(&audit_filter_mutex);
987 return err;
988 }
989 }
990
991 entry->rule.prio = ~0ULL;
992 if (entry->rule.listnr == AUDIT_FILTER_EXIT ||
993 entry->rule.listnr == AUDIT_FILTER_URING_EXIT) {
994 if (entry->rule.flags & AUDIT_FILTER_PREPEND)
995 entry->rule.prio = ++prio_high;
996 else
997 entry->rule.prio = --prio_low;
998 }
999
1000 if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
1001 list_add(&entry->rule.list,
1002 &audit_rules_list[entry->rule.listnr]);
1003 list_add_rcu(&entry->list, list);
1004 entry->rule.flags &= ~AUDIT_FILTER_PREPEND;
1005 } else {
1006 list_add_tail(&entry->rule.list,
1007 &audit_rules_list[entry->rule.listnr]);
1008 list_add_tail_rcu(&entry->list, list);
1009 }
1010#ifdef CONFIG_AUDITSYSCALL
1011 if (!dont_count)
1012 audit_n_rules++;
1013
1014 if (!audit_match_signal(entry))
1015 audit_signals++;
1016#endif
1017 mutex_unlock(&audit_filter_mutex);
1018
1019 return err;
1020}
1021
1022/* Remove an existing rule from filterlist. */
1023int audit_del_rule(struct audit_entry *entry)
1024{
1025 struct audit_entry *e;
1026 struct audit_tree *tree = entry->rule.tree;
1027 struct list_head *list;
1028 int ret = 0;
1029#ifdef CONFIG_AUDITSYSCALL
1030 int dont_count = 0;
1031
1032 /* If any of these, don't count towards total */
1033 switch (entry->rule.listnr) {
1034 case AUDIT_FILTER_USER:
1035 case AUDIT_FILTER_EXCLUDE:
1036 case AUDIT_FILTER_FS:
1037 dont_count = 1;
1038 }
1039#endif
1040
1041 mutex_lock(&audit_filter_mutex);
1042 e = audit_find_rule(entry, &list);
1043 if (!e) {
1044 ret = -ENOENT;
1045 goto out;
1046 }
1047
1048 if (e->rule.watch)
1049 audit_remove_watch_rule(&e->rule);
1050
1051 if (e->rule.tree)
1052 audit_remove_tree_rule(&e->rule);
1053
1054 if (e->rule.exe)
1055 audit_remove_mark_rule(&e->rule);
1056
1057#ifdef CONFIG_AUDITSYSCALL
1058 if (!dont_count)
1059 audit_n_rules--;
1060
1061 if (!audit_match_signal(entry))
1062 audit_signals--;
1063#endif
1064
1065 list_del_rcu(&e->list);
1066 list_del(&e->rule.list);
1067 call_rcu(&e->rcu, audit_free_rule_rcu);
1068
1069out:
1070 mutex_unlock(&audit_filter_mutex);
1071
1072 if (tree)
1073 audit_put_tree(tree); /* that's the temporary one */
1074
1075 return ret;
1076}
1077
1078/* List rules using struct audit_rule_data. */
1079static void audit_list_rules(int seq, struct sk_buff_head *q)
1080{
1081 struct sk_buff *skb;
1082 struct audit_krule *r;
1083 int i;
1084
1085 /* This is a blocking read, so use audit_filter_mutex instead of rcu
1086 * iterator to sync with list writers. */
1087 for (i = 0; i < AUDIT_NR_FILTERS; i++) {
1088 list_for_each_entry(r, &audit_rules_list[i], list) {
1089 struct audit_rule_data *data;
1090
1091 data = audit_krule_to_data(r);
1092 if (unlikely(!data))
1093 break;
1094 skb = audit_make_reply(seq, AUDIT_LIST_RULES, 0, 1,
1095 data,
1096 struct_size(data, buf, data->buflen));
1097 if (skb)
1098 skb_queue_tail(q, skb);
1099 kfree(data);
1100 }
1101 }
1102 skb = audit_make_reply(seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);
1103 if (skb)
1104 skb_queue_tail(q, skb);
1105}
1106
1107/* Log rule additions and removals */
1108static void audit_log_rule_change(char *action, struct audit_krule *rule, int res)
1109{
1110 struct audit_buffer *ab;
1111
1112 if (!audit_enabled)
1113 return;
1114
1115 ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_CONFIG_CHANGE);
1116 if (!ab)
1117 return;
1118 audit_log_session_info(ab);
1119 audit_log_task_context(ab);
1120 audit_log_format(ab, " op=%s", action);
1121 audit_log_key(ab, rule->filterkey);
1122 audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
1123 audit_log_end(ab);
1124}
1125
1126/**
1127 * audit_rule_change - apply all rules to the specified message type
1128 * @type: audit message type
1129 * @seq: netlink audit message sequence (serial) number
1130 * @data: payload data
1131 * @datasz: size of payload data
1132 */
1133int audit_rule_change(int type, int seq, void *data, size_t datasz)
1134{
1135 int err = 0;
1136 struct audit_entry *entry;
1137
1138 switch (type) {
1139 case AUDIT_ADD_RULE:
1140 entry = audit_data_to_entry(data, datasz);
1141 if (IS_ERR(entry))
1142 return PTR_ERR(entry);
1143 err = audit_add_rule(entry);
1144 audit_log_rule_change("add_rule", &entry->rule, !err);
1145 break;
1146 case AUDIT_DEL_RULE:
1147 entry = audit_data_to_entry(data, datasz);
1148 if (IS_ERR(entry))
1149 return PTR_ERR(entry);
1150 err = audit_del_rule(entry);
1151 audit_log_rule_change("remove_rule", &entry->rule, !err);
1152 break;
1153 default:
1154 WARN_ON(1);
1155 return -EINVAL;
1156 }
1157
1158 if (err || type == AUDIT_DEL_RULE) {
1159 if (entry->rule.exe)
1160 audit_remove_mark(entry->rule.exe);
1161 audit_free_rule(entry);
1162 }
1163
1164 return err;
1165}
1166
1167/**
1168 * audit_list_rules_send - list the audit rules
1169 * @request_skb: skb of request we are replying to (used to target the reply)
1170 * @seq: netlink audit message sequence (serial) number
1171 */
1172int audit_list_rules_send(struct sk_buff *request_skb, int seq)
1173{
1174 struct task_struct *tsk;
1175 struct audit_netlink_list *dest;
1176
1177 /* We can't just spew out the rules here because we might fill
1178 * the available socket buffer space and deadlock waiting for
1179 * auditctl to read from it... which isn't ever going to
1180 * happen if we're actually running in the context of auditctl
1181 * trying to _send_ the stuff */
1182
1183 dest = kmalloc(sizeof(*dest), GFP_KERNEL);
1184 if (!dest)
1185 return -ENOMEM;
1186 dest->net = get_net(sock_net(NETLINK_CB(request_skb).sk));
1187 dest->portid = NETLINK_CB(request_skb).portid;
1188 skb_queue_head_init(&dest->q);
1189
1190 mutex_lock(&audit_filter_mutex);
1191 audit_list_rules(seq, &dest->q);
1192 mutex_unlock(&audit_filter_mutex);
1193
1194 tsk = kthread_run(audit_send_list_thread, dest, "audit_send_list");
1195 if (IS_ERR(tsk)) {
1196 skb_queue_purge(&dest->q);
1197 put_net(dest->net);
1198 kfree(dest);
1199 return PTR_ERR(tsk);
1200 }
1201
1202 return 0;
1203}
1204
1205int audit_comparator(u32 left, u32 op, u32 right)
1206{
1207 switch (op) {
1208 case Audit_equal:
1209 return (left == right);
1210 case Audit_not_equal:
1211 return (left != right);
1212 case Audit_lt:
1213 return (left < right);
1214 case Audit_le:
1215 return (left <= right);
1216 case Audit_gt:
1217 return (left > right);
1218 case Audit_ge:
1219 return (left >= right);
1220 case Audit_bitmask:
1221 return (left & right);
1222 case Audit_bittest:
1223 return ((left & right) == right);
1224 default:
1225 return 0;
1226 }
1227}
1228
1229int audit_uid_comparator(kuid_t left, u32 op, kuid_t right)
1230{
1231 switch (op) {
1232 case Audit_equal:
1233 return uid_eq(left, right);
1234 case Audit_not_equal:
1235 return !uid_eq(left, right);
1236 case Audit_lt:
1237 return uid_lt(left, right);
1238 case Audit_le:
1239 return uid_lte(left, right);
1240 case Audit_gt:
1241 return uid_gt(left, right);
1242 case Audit_ge:
1243 return uid_gte(left, right);
1244 case Audit_bitmask:
1245 case Audit_bittest:
1246 default:
1247 return 0;
1248 }
1249}
1250
1251int audit_gid_comparator(kgid_t left, u32 op, kgid_t right)
1252{
1253 switch (op) {
1254 case Audit_equal:
1255 return gid_eq(left, right);
1256 case Audit_not_equal:
1257 return !gid_eq(left, right);
1258 case Audit_lt:
1259 return gid_lt(left, right);
1260 case Audit_le:
1261 return gid_lte(left, right);
1262 case Audit_gt:
1263 return gid_gt(left, right);
1264 case Audit_ge:
1265 return gid_gte(left, right);
1266 case Audit_bitmask:
1267 case Audit_bittest:
1268 default:
1269 return 0;
1270 }
1271}
1272
1273/**
1274 * parent_len - find the length of the parent portion of a pathname
1275 * @path: pathname of which to determine length
1276 */
1277int parent_len(const char *path)
1278{
1279 int plen;
1280 const char *p;
1281
1282 plen = strlen(path);
1283
1284 if (plen == 0)
1285 return plen;
1286
1287 /* disregard trailing slashes */
1288 p = path + plen - 1;
1289 while ((*p == '/') && (p > path))
1290 p--;
1291
1292 /* walk backward until we find the next slash or hit beginning */
1293 while ((*p != '/') && (p > path))
1294 p--;
1295
1296 /* did we find a slash? Then increment to include it in path */
1297 if (*p == '/')
1298 p++;
1299
1300 return p - path;
1301}
1302
1303/**
1304 * audit_compare_dname_path - compare given dentry name with last component in
1305 * given path. Return of 0 indicates a match.
1306 * @dname: dentry name that we're comparing
1307 * @path: full pathname that we're comparing
1308 * @parentlen: length of the parent if known. Passing in AUDIT_NAME_FULL
1309 * here indicates that we must compute this value.
1310 */
1311int audit_compare_dname_path(const struct qstr *dname, const char *path, int parentlen)
1312{
1313 int dlen, pathlen;
1314 const char *p;
1315
1316 dlen = dname->len;
1317 pathlen = strlen(path);
1318 if (pathlen < dlen)
1319 return 1;
1320
1321 parentlen = parentlen == AUDIT_NAME_FULL ? parent_len(path) : parentlen;
1322 if (pathlen - parentlen != dlen)
1323 return 1;
1324
1325 p = path + parentlen;
1326
1327 return strncmp(p, dname->name, dlen);
1328}
1329
1330int audit_filter(int msgtype, unsigned int listtype)
1331{
1332 struct audit_entry *e;
1333 int ret = 1; /* Audit by default */
1334
1335 rcu_read_lock();
1336 list_for_each_entry_rcu(e, &audit_filter_list[listtype], list) {
1337 int i, result = 0;
1338
1339 for (i = 0; i < e->rule.field_count; i++) {
1340 struct audit_field *f = &e->rule.fields[i];
1341 pid_t pid;
1342 u32 sid;
1343
1344 switch (f->type) {
1345 case AUDIT_PID:
1346 pid = task_pid_nr(current);
1347 result = audit_comparator(pid, f->op, f->val);
1348 break;
1349 case AUDIT_UID:
1350 result = audit_uid_comparator(current_uid(), f->op, f->uid);
1351 break;
1352 case AUDIT_GID:
1353 result = audit_gid_comparator(current_gid(), f->op, f->gid);
1354 break;
1355 case AUDIT_LOGINUID:
1356 result = audit_uid_comparator(audit_get_loginuid(current),
1357 f->op, f->uid);
1358 break;
1359 case AUDIT_LOGINUID_SET:
1360 result = audit_comparator(audit_loginuid_set(current),
1361 f->op, f->val);
1362 break;
1363 case AUDIT_MSGTYPE:
1364 result = audit_comparator(msgtype, f->op, f->val);
1365 break;
1366 case AUDIT_SUBJ_USER:
1367 case AUDIT_SUBJ_ROLE:
1368 case AUDIT_SUBJ_TYPE:
1369 case AUDIT_SUBJ_SEN:
1370 case AUDIT_SUBJ_CLR:
1371 if (f->lsm_rule) {
1372 security_current_getsecid_subj(&sid);
1373 result = security_audit_rule_match(sid,
1374 f->type, f->op, f->lsm_rule);
1375 }
1376 break;
1377 case AUDIT_EXE:
1378 result = audit_exe_compare(current, e->rule.exe);
1379 if (f->op == Audit_not_equal)
1380 result = !result;
1381 break;
1382 default:
1383 goto unlock_and_return;
1384 }
1385 if (result < 0) /* error */
1386 goto unlock_and_return;
1387 if (!result)
1388 break;
1389 }
1390 if (result > 0) {
1391 if (e->rule.action == AUDIT_NEVER || listtype == AUDIT_FILTER_EXCLUDE)
1392 ret = 0;
1393 break;
1394 }
1395 }
1396unlock_and_return:
1397 rcu_read_unlock();
1398 return ret;
1399}
1400
1401static int update_lsm_rule(struct audit_krule *r)
1402{
1403 struct audit_entry *entry = container_of(r, struct audit_entry, rule);
1404 struct audit_entry *nentry;
1405 int err = 0;
1406
1407 if (!security_audit_rule_known(r))
1408 return 0;
1409
1410 nentry = audit_dupe_rule(r);
1411 if (entry->rule.exe)
1412 audit_remove_mark(entry->rule.exe);
1413 if (IS_ERR(nentry)) {
1414 /* save the first error encountered for the
1415 * return value */
1416 err = PTR_ERR(nentry);
1417 audit_panic("error updating LSM filters");
1418 if (r->watch)
1419 list_del(&r->rlist);
1420 list_del_rcu(&entry->list);
1421 list_del(&r->list);
1422 } else {
1423 if (r->watch || r->tree)
1424 list_replace_init(&r->rlist, &nentry->rule.rlist);
1425 list_replace_rcu(&entry->list, &nentry->list);
1426 list_replace(&r->list, &nentry->rule.list);
1427 }
1428 call_rcu(&entry->rcu, audit_free_rule_rcu);
1429
1430 return err;
1431}
1432
1433/* This function will re-initialize the lsm_rule field of all applicable rules.
1434 * It will traverse the filter lists serarching for rules that contain LSM
1435 * specific filter fields. When such a rule is found, it is copied, the
1436 * LSM field is re-initialized, and the old rule is replaced with the
1437 * updated rule. */
1438int audit_update_lsm_rules(void)
1439{
1440 struct audit_krule *r, *n;
1441 int i, err = 0;
1442
1443 /* audit_filter_mutex synchronizes the writers */
1444 mutex_lock(&audit_filter_mutex);
1445
1446 for (i = 0; i < AUDIT_NR_FILTERS; i++) {
1447 list_for_each_entry_safe(r, n, &audit_rules_list[i], list) {
1448 int res = update_lsm_rule(r);
1449 if (!err)
1450 err = res;
1451 }
1452 }
1453 mutex_unlock(&audit_filter_mutex);
1454
1455 return err;
1456}
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 case AUDIT_FILTER_USER:
239 case AUDIT_FILTER_TYPE:
240#ifdef CONFIG_AUDITSYSCALL
241 case AUDIT_FILTER_ENTRY:
242 case AUDIT_FILTER_EXIT:
243 case AUDIT_FILTER_TASK:
244#endif
245 ;
246 }
247 if (unlikely(rule->action == AUDIT_POSSIBLE)) {
248 printk(KERN_ERR "AUDIT_POSSIBLE is deprecated\n");
249 goto exit_err;
250 }
251 if (rule->action != AUDIT_NEVER && rule->action != AUDIT_ALWAYS)
252 goto exit_err;
253 if (rule->field_count > AUDIT_MAX_FIELDS)
254 goto exit_err;
255
256 err = -ENOMEM;
257 entry = audit_init_entry(rule->field_count);
258 if (!entry)
259 goto exit_err;
260
261 entry->rule.flags = rule->flags & AUDIT_FILTER_PREPEND;
262 entry->rule.listnr = listnr;
263 entry->rule.action = rule->action;
264 entry->rule.field_count = rule->field_count;
265
266 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
267 entry->rule.mask[i] = rule->mask[i];
268
269 for (i = 0; i < AUDIT_SYSCALL_CLASSES; i++) {
270 int bit = AUDIT_BITMASK_SIZE * 32 - i - 1;
271 __u32 *p = &entry->rule.mask[AUDIT_WORD(bit)];
272 __u32 *class;
273
274 if (!(*p & AUDIT_BIT(bit)))
275 continue;
276 *p &= ~AUDIT_BIT(bit);
277 class = classes[i];
278 if (class) {
279 int j;
280 for (j = 0; j < AUDIT_BITMASK_SIZE; j++)
281 entry->rule.mask[j] |= class[j];
282 }
283 }
284
285 return entry;
286
287exit_err:
288 return ERR_PTR(err);
289}
290
291static u32 audit_ops[] =
292{
293 [Audit_equal] = AUDIT_EQUAL,
294 [Audit_not_equal] = AUDIT_NOT_EQUAL,
295 [Audit_bitmask] = AUDIT_BIT_MASK,
296 [Audit_bittest] = AUDIT_BIT_TEST,
297 [Audit_lt] = AUDIT_LESS_THAN,
298 [Audit_gt] = AUDIT_GREATER_THAN,
299 [Audit_le] = AUDIT_LESS_THAN_OR_EQUAL,
300 [Audit_ge] = AUDIT_GREATER_THAN_OR_EQUAL,
301};
302
303static u32 audit_to_op(u32 op)
304{
305 u32 n;
306 for (n = Audit_equal; n < Audit_bad && audit_ops[n] != op; n++)
307 ;
308 return n;
309}
310
311
312/* Translate struct audit_rule to kernel's rule respresentation.
313 * Exists for backward compatibility with userspace. */
314static struct audit_entry *audit_rule_to_entry(struct audit_rule *rule)
315{
316 struct audit_entry *entry;
317 int err = 0;
318 int i;
319
320 entry = audit_to_entry_common(rule);
321 if (IS_ERR(entry))
322 goto exit_nofree;
323
324 for (i = 0; i < rule->field_count; i++) {
325 struct audit_field *f = &entry->rule.fields[i];
326 u32 n;
327
328 n = rule->fields[i] & (AUDIT_NEGATE|AUDIT_OPERATORS);
329
330 /* Support for legacy operators where
331 * AUDIT_NEGATE bit signifies != and otherwise assumes == */
332 if (n & AUDIT_NEGATE)
333 f->op = Audit_not_equal;
334 else if (!n)
335 f->op = Audit_equal;
336 else
337 f->op = audit_to_op(n);
338
339 entry->rule.vers_ops = (n & AUDIT_OPERATORS) ? 2 : 1;
340
341 f->type = rule->fields[i] & ~(AUDIT_NEGATE|AUDIT_OPERATORS);
342 f->val = rule->values[i];
343
344 err = -EINVAL;
345 if (f->op == Audit_bad)
346 goto exit_free;
347
348 switch(f->type) {
349 default:
350 goto exit_free;
351 case AUDIT_PID:
352 case AUDIT_UID:
353 case AUDIT_EUID:
354 case AUDIT_SUID:
355 case AUDIT_FSUID:
356 case AUDIT_GID:
357 case AUDIT_EGID:
358 case AUDIT_SGID:
359 case AUDIT_FSGID:
360 case AUDIT_LOGINUID:
361 case AUDIT_PERS:
362 case AUDIT_MSGTYPE:
363 case AUDIT_PPID:
364 case AUDIT_DEVMAJOR:
365 case AUDIT_DEVMINOR:
366 case AUDIT_EXIT:
367 case AUDIT_SUCCESS:
368 /* bit ops are only useful on syscall args */
369 if (f->op == Audit_bitmask || f->op == Audit_bittest)
370 goto exit_free;
371 break;
372 case AUDIT_ARG0:
373 case AUDIT_ARG1:
374 case AUDIT_ARG2:
375 case AUDIT_ARG3:
376 break;
377 /* arch is only allowed to be = or != */
378 case AUDIT_ARCH:
379 if (f->op != Audit_not_equal && f->op != Audit_equal)
380 goto exit_free;
381 entry->rule.arch_f = f;
382 break;
383 case AUDIT_PERM:
384 if (f->val & ~15)
385 goto exit_free;
386 break;
387 case AUDIT_FILETYPE:
388 if ((f->val & ~S_IFMT) > S_IFMT)
389 goto exit_free;
390 break;
391 case AUDIT_INODE:
392 err = audit_to_inode(&entry->rule, f);
393 if (err)
394 goto exit_free;
395 break;
396 }
397 }
398
399 if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal)
400 entry->rule.inode_f = NULL;
401
402exit_nofree:
403 return entry;
404
405exit_free:
406 audit_free_rule(entry);
407 return ERR_PTR(err);
408}
409
410/* Translate struct audit_rule_data to kernel's rule respresentation. */
411static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
412 size_t datasz)
413{
414 int err = 0;
415 struct audit_entry *entry;
416 void *bufp;
417 size_t remain = datasz - sizeof(struct audit_rule_data);
418 int i;
419 char *str;
420
421 entry = audit_to_entry_common((struct audit_rule *)data);
422 if (IS_ERR(entry))
423 goto exit_nofree;
424
425 bufp = data->buf;
426 entry->rule.vers_ops = 2;
427 for (i = 0; i < data->field_count; i++) {
428 struct audit_field *f = &entry->rule.fields[i];
429
430 err = -EINVAL;
431
432 f->op = audit_to_op(data->fieldflags[i]);
433 if (f->op == Audit_bad)
434 goto exit_free;
435
436 f->type = data->fields[i];
437 f->val = data->values[i];
438 f->lsm_str = NULL;
439 f->lsm_rule = NULL;
440 switch(f->type) {
441 case AUDIT_PID:
442 case AUDIT_UID:
443 case AUDIT_EUID:
444 case AUDIT_SUID:
445 case AUDIT_FSUID:
446 case AUDIT_GID:
447 case AUDIT_EGID:
448 case AUDIT_SGID:
449 case AUDIT_FSGID:
450 case AUDIT_LOGINUID:
451 case AUDIT_PERS:
452 case AUDIT_MSGTYPE:
453 case AUDIT_PPID:
454 case AUDIT_DEVMAJOR:
455 case AUDIT_DEVMINOR:
456 case AUDIT_EXIT:
457 case AUDIT_SUCCESS:
458 case AUDIT_ARG0:
459 case AUDIT_ARG1:
460 case AUDIT_ARG2:
461 case AUDIT_ARG3:
462 break;
463 case AUDIT_ARCH:
464 entry->rule.arch_f = f;
465 break;
466 case AUDIT_SUBJ_USER:
467 case AUDIT_SUBJ_ROLE:
468 case AUDIT_SUBJ_TYPE:
469 case AUDIT_SUBJ_SEN:
470 case AUDIT_SUBJ_CLR:
471 case AUDIT_OBJ_USER:
472 case AUDIT_OBJ_ROLE:
473 case AUDIT_OBJ_TYPE:
474 case AUDIT_OBJ_LEV_LOW:
475 case AUDIT_OBJ_LEV_HIGH:
476 str = audit_unpack_string(&bufp, &remain, f->val);
477 if (IS_ERR(str))
478 goto exit_free;
479 entry->rule.buflen += f->val;
480
481 err = security_audit_rule_init(f->type, f->op, str,
482 (void **)&f->lsm_rule);
483 /* Keep currently invalid fields around in case they
484 * become valid after a policy reload. */
485 if (err == -EINVAL) {
486 printk(KERN_WARNING "audit rule for LSM "
487 "\'%s\' is invalid\n", str);
488 err = 0;
489 }
490 if (err) {
491 kfree(str);
492 goto exit_free;
493 } else
494 f->lsm_str = str;
495 break;
496 case AUDIT_WATCH:
497 str = audit_unpack_string(&bufp, &remain, f->val);
498 if (IS_ERR(str))
499 goto exit_free;
500 entry->rule.buflen += f->val;
501
502 err = audit_to_watch(&entry->rule, str, f->val, f->op);
503 if (err) {
504 kfree(str);
505 goto exit_free;
506 }
507 break;
508 case AUDIT_DIR:
509 str = audit_unpack_string(&bufp, &remain, f->val);
510 if (IS_ERR(str))
511 goto exit_free;
512 entry->rule.buflen += f->val;
513
514 err = audit_make_tree(&entry->rule, str, f->op);
515 kfree(str);
516 if (err)
517 goto exit_free;
518 break;
519 case AUDIT_INODE:
520 err = audit_to_inode(&entry->rule, f);
521 if (err)
522 goto exit_free;
523 break;
524 case AUDIT_FILTERKEY:
525 err = -EINVAL;
526 if (entry->rule.filterkey || f->val > AUDIT_MAX_KEY_LEN)
527 goto exit_free;
528 str = audit_unpack_string(&bufp, &remain, f->val);
529 if (IS_ERR(str))
530 goto exit_free;
531 entry->rule.buflen += f->val;
532 entry->rule.filterkey = str;
533 break;
534 case AUDIT_PERM:
535 if (f->val & ~15)
536 goto exit_free;
537 break;
538 case AUDIT_FILETYPE:
539 if ((f->val & ~S_IFMT) > S_IFMT)
540 goto exit_free;
541 break;
542 default:
543 goto exit_free;
544 }
545 }
546
547 if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal)
548 entry->rule.inode_f = NULL;
549
550exit_nofree:
551 return entry;
552
553exit_free:
554 audit_free_rule(entry);
555 return ERR_PTR(err);
556}
557
558/* Pack a filter field's string representation into data block. */
559static inline size_t audit_pack_string(void **bufp, const char *str)
560{
561 size_t len = strlen(str);
562
563 memcpy(*bufp, str, len);
564 *bufp += len;
565
566 return len;
567}
568
569/* Translate kernel rule respresentation to struct audit_rule.
570 * Exists for backward compatibility with userspace. */
571static struct audit_rule *audit_krule_to_rule(struct audit_krule *krule)
572{
573 struct audit_rule *rule;
574 int i;
575
576 rule = kzalloc(sizeof(*rule), GFP_KERNEL);
577 if (unlikely(!rule))
578 return NULL;
579
580 rule->flags = krule->flags | krule->listnr;
581 rule->action = krule->action;
582 rule->field_count = krule->field_count;
583 for (i = 0; i < rule->field_count; i++) {
584 rule->values[i] = krule->fields[i].val;
585 rule->fields[i] = krule->fields[i].type;
586
587 if (krule->vers_ops == 1) {
588 if (krule->fields[i].op == Audit_not_equal)
589 rule->fields[i] |= AUDIT_NEGATE;
590 } else {
591 rule->fields[i] |= audit_ops[krule->fields[i].op];
592 }
593 }
594 for (i = 0; i < AUDIT_BITMASK_SIZE; i++) rule->mask[i] = krule->mask[i];
595
596 return rule;
597}
598
599/* Translate kernel rule respresentation to struct audit_rule_data. */
600static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule)
601{
602 struct audit_rule_data *data;
603 void *bufp;
604 int i;
605
606 data = kmalloc(sizeof(*data) + krule->buflen, GFP_KERNEL);
607 if (unlikely(!data))
608 return NULL;
609 memset(data, 0, sizeof(*data));
610
611 data->flags = krule->flags | krule->listnr;
612 data->action = krule->action;
613 data->field_count = krule->field_count;
614 bufp = data->buf;
615 for (i = 0; i < data->field_count; i++) {
616 struct audit_field *f = &krule->fields[i];
617
618 data->fields[i] = f->type;
619 data->fieldflags[i] = audit_ops[f->op];
620 switch(f->type) {
621 case AUDIT_SUBJ_USER:
622 case AUDIT_SUBJ_ROLE:
623 case AUDIT_SUBJ_TYPE:
624 case AUDIT_SUBJ_SEN:
625 case AUDIT_SUBJ_CLR:
626 case AUDIT_OBJ_USER:
627 case AUDIT_OBJ_ROLE:
628 case AUDIT_OBJ_TYPE:
629 case AUDIT_OBJ_LEV_LOW:
630 case AUDIT_OBJ_LEV_HIGH:
631 data->buflen += data->values[i] =
632 audit_pack_string(&bufp, f->lsm_str);
633 break;
634 case AUDIT_WATCH:
635 data->buflen += data->values[i] =
636 audit_pack_string(&bufp,
637 audit_watch_path(krule->watch));
638 break;
639 case AUDIT_DIR:
640 data->buflen += data->values[i] =
641 audit_pack_string(&bufp,
642 audit_tree_path(krule->tree));
643 break;
644 case AUDIT_FILTERKEY:
645 data->buflen += data->values[i] =
646 audit_pack_string(&bufp, krule->filterkey);
647 break;
648 default:
649 data->values[i] = f->val;
650 }
651 }
652 for (i = 0; i < AUDIT_BITMASK_SIZE; i++) data->mask[i] = krule->mask[i];
653
654 return data;
655}
656
657/* Compare two rules in kernel format. Considered success if rules
658 * don't match. */
659static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
660{
661 int i;
662
663 if (a->flags != b->flags ||
664 a->listnr != b->listnr ||
665 a->action != b->action ||
666 a->field_count != b->field_count)
667 return 1;
668
669 for (i = 0; i < a->field_count; i++) {
670 if (a->fields[i].type != b->fields[i].type ||
671 a->fields[i].op != b->fields[i].op)
672 return 1;
673
674 switch(a->fields[i].type) {
675 case AUDIT_SUBJ_USER:
676 case AUDIT_SUBJ_ROLE:
677 case AUDIT_SUBJ_TYPE:
678 case AUDIT_SUBJ_SEN:
679 case AUDIT_SUBJ_CLR:
680 case AUDIT_OBJ_USER:
681 case AUDIT_OBJ_ROLE:
682 case AUDIT_OBJ_TYPE:
683 case AUDIT_OBJ_LEV_LOW:
684 case AUDIT_OBJ_LEV_HIGH:
685 if (strcmp(a->fields[i].lsm_str, b->fields[i].lsm_str))
686 return 1;
687 break;
688 case AUDIT_WATCH:
689 if (strcmp(audit_watch_path(a->watch),
690 audit_watch_path(b->watch)))
691 return 1;
692 break;
693 case AUDIT_DIR:
694 if (strcmp(audit_tree_path(a->tree),
695 audit_tree_path(b->tree)))
696 return 1;
697 break;
698 case AUDIT_FILTERKEY:
699 /* both filterkeys exist based on above type compare */
700 if (strcmp(a->filterkey, b->filterkey))
701 return 1;
702 break;
703 default:
704 if (a->fields[i].val != b->fields[i].val)
705 return 1;
706 }
707 }
708
709 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
710 if (a->mask[i] != b->mask[i])
711 return 1;
712
713 return 0;
714}
715
716/* Duplicate LSM field information. The lsm_rule is opaque, so must be
717 * re-initialized. */
718static inline int audit_dupe_lsm_field(struct audit_field *df,
719 struct audit_field *sf)
720{
721 int ret = 0;
722 char *lsm_str;
723
724 /* our own copy of lsm_str */
725 lsm_str = kstrdup(sf->lsm_str, GFP_KERNEL);
726 if (unlikely(!lsm_str))
727 return -ENOMEM;
728 df->lsm_str = lsm_str;
729
730 /* our own (refreshed) copy of lsm_rule */
731 ret = security_audit_rule_init(df->type, df->op, df->lsm_str,
732 (void **)&df->lsm_rule);
733 /* Keep currently invalid fields around in case they
734 * become valid after a policy reload. */
735 if (ret == -EINVAL) {
736 printk(KERN_WARNING "audit rule for LSM \'%s\' is "
737 "invalid\n", df->lsm_str);
738 ret = 0;
739 }
740
741 return ret;
742}
743
744/* Duplicate an audit rule. This will be a deep copy with the exception
745 * of the watch - that pointer is carried over. The LSM specific fields
746 * will be updated in the copy. The point is to be able to replace the old
747 * rule with the new rule in the filterlist, then free the old rule.
748 * The rlist element is undefined; list manipulations are handled apart from
749 * the initial copy. */
750struct audit_entry *audit_dupe_rule(struct audit_krule *old)
751{
752 u32 fcount = old->field_count;
753 struct audit_entry *entry;
754 struct audit_krule *new;
755 char *fk;
756 int i, err = 0;
757
758 entry = audit_init_entry(fcount);
759 if (unlikely(!entry))
760 return ERR_PTR(-ENOMEM);
761
762 new = &entry->rule;
763 new->vers_ops = old->vers_ops;
764 new->flags = old->flags;
765 new->listnr = old->listnr;
766 new->action = old->action;
767 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
768 new->mask[i] = old->mask[i];
769 new->prio = old->prio;
770 new->buflen = old->buflen;
771 new->inode_f = old->inode_f;
772 new->field_count = old->field_count;
773
774 /*
775 * note that we are OK with not refcounting here; audit_match_tree()
776 * never dereferences tree and we can't get false positives there
777 * since we'd have to have rule gone from the list *and* removed
778 * before the chunks found by lookup had been allocated, i.e. before
779 * the beginning of list scan.
780 */
781 new->tree = old->tree;
782 memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount);
783
784 /* deep copy this information, updating the lsm_rule fields, because
785 * the originals will all be freed when the old rule is freed. */
786 for (i = 0; i < fcount; i++) {
787 switch (new->fields[i].type) {
788 case AUDIT_SUBJ_USER:
789 case AUDIT_SUBJ_ROLE:
790 case AUDIT_SUBJ_TYPE:
791 case AUDIT_SUBJ_SEN:
792 case AUDIT_SUBJ_CLR:
793 case AUDIT_OBJ_USER:
794 case AUDIT_OBJ_ROLE:
795 case AUDIT_OBJ_TYPE:
796 case AUDIT_OBJ_LEV_LOW:
797 case AUDIT_OBJ_LEV_HIGH:
798 err = audit_dupe_lsm_field(&new->fields[i],
799 &old->fields[i]);
800 break;
801 case AUDIT_FILTERKEY:
802 fk = kstrdup(old->filterkey, GFP_KERNEL);
803 if (unlikely(!fk))
804 err = -ENOMEM;
805 else
806 new->filterkey = fk;
807 }
808 if (err) {
809 audit_free_rule(entry);
810 return ERR_PTR(err);
811 }
812 }
813
814 if (old->watch) {
815 audit_get_watch(old->watch);
816 new->watch = old->watch;
817 }
818
819 return entry;
820}
821
822/* Find an existing audit rule.
823 * Caller must hold audit_filter_mutex to prevent stale rule data. */
824static struct audit_entry *audit_find_rule(struct audit_entry *entry,
825 struct list_head **p)
826{
827 struct audit_entry *e, *found = NULL;
828 struct list_head *list;
829 int h;
830
831 if (entry->rule.inode_f) {
832 h = audit_hash_ino(entry->rule.inode_f->val);
833 *p = list = &audit_inode_hash[h];
834 } else if (entry->rule.watch) {
835 /* we don't know the inode number, so must walk entire hash */
836 for (h = 0; h < AUDIT_INODE_BUCKETS; h++) {
837 list = &audit_inode_hash[h];
838 list_for_each_entry(e, list, list)
839 if (!audit_compare_rule(&entry->rule, &e->rule)) {
840 found = e;
841 goto out;
842 }
843 }
844 goto out;
845 } else {
846 *p = list = &audit_filter_list[entry->rule.listnr];
847 }
848
849 list_for_each_entry(e, list, list)
850 if (!audit_compare_rule(&entry->rule, &e->rule)) {
851 found = e;
852 goto out;
853 }
854
855out:
856 return found;
857}
858
859static u64 prio_low = ~0ULL/2;
860static u64 prio_high = ~0ULL/2 - 1;
861
862/* Add rule to given filterlist if not a duplicate. */
863static inline int audit_add_rule(struct audit_entry *entry)
864{
865 struct audit_entry *e;
866 struct audit_watch *watch = entry->rule.watch;
867 struct audit_tree *tree = entry->rule.tree;
868 struct list_head *list;
869 int err;
870#ifdef CONFIG_AUDITSYSCALL
871 int dont_count = 0;
872
873 /* If either of these, don't count towards total */
874 if (entry->rule.listnr == AUDIT_FILTER_USER ||
875 entry->rule.listnr == AUDIT_FILTER_TYPE)
876 dont_count = 1;
877#endif
878
879 mutex_lock(&audit_filter_mutex);
880 e = audit_find_rule(entry, &list);
881 if (e) {
882 mutex_unlock(&audit_filter_mutex);
883 err = -EEXIST;
884 /* normally audit_add_tree_rule() will free it on failure */
885 if (tree)
886 audit_put_tree(tree);
887 goto error;
888 }
889
890 if (watch) {
891 /* audit_filter_mutex is dropped and re-taken during this call */
892 err = audit_add_watch(&entry->rule, &list);
893 if (err) {
894 mutex_unlock(&audit_filter_mutex);
895 goto error;
896 }
897 }
898 if (tree) {
899 err = audit_add_tree_rule(&entry->rule);
900 if (err) {
901 mutex_unlock(&audit_filter_mutex);
902 goto error;
903 }
904 }
905
906 entry->rule.prio = ~0ULL;
907 if (entry->rule.listnr == AUDIT_FILTER_EXIT) {
908 if (entry->rule.flags & AUDIT_FILTER_PREPEND)
909 entry->rule.prio = ++prio_high;
910 else
911 entry->rule.prio = --prio_low;
912 }
913
914 if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
915 list_add(&entry->rule.list,
916 &audit_rules_list[entry->rule.listnr]);
917 list_add_rcu(&entry->list, list);
918 entry->rule.flags &= ~AUDIT_FILTER_PREPEND;
919 } else {
920 list_add_tail(&entry->rule.list,
921 &audit_rules_list[entry->rule.listnr]);
922 list_add_tail_rcu(&entry->list, list);
923 }
924#ifdef CONFIG_AUDITSYSCALL
925 if (!dont_count)
926 audit_n_rules++;
927
928 if (!audit_match_signal(entry))
929 audit_signals++;
930#endif
931 mutex_unlock(&audit_filter_mutex);
932
933 return 0;
934
935error:
936 if (watch)
937 audit_put_watch(watch); /* tmp watch, matches initial get */
938 return err;
939}
940
941/* Remove an existing rule from filterlist. */
942static inline int audit_del_rule(struct audit_entry *entry)
943{
944 struct audit_entry *e;
945 struct audit_watch *watch = entry->rule.watch;
946 struct audit_tree *tree = entry->rule.tree;
947 struct list_head *list;
948 int ret = 0;
949#ifdef CONFIG_AUDITSYSCALL
950 int dont_count = 0;
951
952 /* If either of these, don't count towards total */
953 if (entry->rule.listnr == AUDIT_FILTER_USER ||
954 entry->rule.listnr == AUDIT_FILTER_TYPE)
955 dont_count = 1;
956#endif
957
958 mutex_lock(&audit_filter_mutex);
959 e = audit_find_rule(entry, &list);
960 if (!e) {
961 mutex_unlock(&audit_filter_mutex);
962 ret = -ENOENT;
963 goto out;
964 }
965
966 if (e->rule.watch)
967 audit_remove_watch_rule(&e->rule);
968
969 if (e->rule.tree)
970 audit_remove_tree_rule(&e->rule);
971
972 list_del_rcu(&e->list);
973 list_del(&e->rule.list);
974 call_rcu(&e->rcu, audit_free_rule_rcu);
975
976#ifdef CONFIG_AUDITSYSCALL
977 if (!dont_count)
978 audit_n_rules--;
979
980 if (!audit_match_signal(entry))
981 audit_signals--;
982#endif
983 mutex_unlock(&audit_filter_mutex);
984
985out:
986 if (watch)
987 audit_put_watch(watch); /* match initial get */
988 if (tree)
989 audit_put_tree(tree); /* that's the temporary one */
990
991 return ret;
992}
993
994/* List rules using struct audit_rule. Exists for backward
995 * compatibility with userspace. */
996static void audit_list(int pid, int seq, struct sk_buff_head *q)
997{
998 struct sk_buff *skb;
999 struct audit_krule *r;
1000 int i;
1001
1002 /* This is a blocking read, so use audit_filter_mutex instead of rcu
1003 * iterator to sync with list writers. */
1004 for (i=0; i<AUDIT_NR_FILTERS; i++) {
1005 list_for_each_entry(r, &audit_rules_list[i], list) {
1006 struct audit_rule *rule;
1007
1008 rule = audit_krule_to_rule(r);
1009 if (unlikely(!rule))
1010 break;
1011 skb = audit_make_reply(pid, seq, AUDIT_LIST, 0, 1,
1012 rule, sizeof(*rule));
1013 if (skb)
1014 skb_queue_tail(q, skb);
1015 kfree(rule);
1016 }
1017 }
1018 skb = audit_make_reply(pid, seq, AUDIT_LIST, 1, 1, NULL, 0);
1019 if (skb)
1020 skb_queue_tail(q, skb);
1021}
1022
1023/* List rules using struct audit_rule_data. */
1024static void audit_list_rules(int pid, int seq, struct sk_buff_head *q)
1025{
1026 struct sk_buff *skb;
1027 struct audit_krule *r;
1028 int i;
1029
1030 /* This is a blocking read, so use audit_filter_mutex instead of rcu
1031 * iterator to sync with list writers. */
1032 for (i=0; i<AUDIT_NR_FILTERS; i++) {
1033 list_for_each_entry(r, &audit_rules_list[i], list) {
1034 struct audit_rule_data *data;
1035
1036 data = audit_krule_to_data(r);
1037 if (unlikely(!data))
1038 break;
1039 skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 0, 1,
1040 data, sizeof(*data) + data->buflen);
1041 if (skb)
1042 skb_queue_tail(q, skb);
1043 kfree(data);
1044 }
1045 }
1046 skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);
1047 if (skb)
1048 skb_queue_tail(q, skb);
1049}
1050
1051/* Log rule additions and removals */
1052static void audit_log_rule_change(uid_t loginuid, u32 sessionid, u32 sid,
1053 char *action, struct audit_krule *rule,
1054 int res)
1055{
1056 struct audit_buffer *ab;
1057
1058 if (!audit_enabled)
1059 return;
1060
1061 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
1062 if (!ab)
1063 return;
1064 audit_log_format(ab, "auid=%u ses=%u", loginuid, sessionid);
1065 if (sid) {
1066 char *ctx = NULL;
1067 u32 len;
1068 if (security_secid_to_secctx(sid, &ctx, &len))
1069 audit_log_format(ab, " ssid=%u", sid);
1070 else {
1071 audit_log_format(ab, " subj=%s", ctx);
1072 security_release_secctx(ctx, len);
1073 }
1074 }
1075 audit_log_format(ab, " op=");
1076 audit_log_string(ab, action);
1077 audit_log_key(ab, rule->filterkey);
1078 audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
1079 audit_log_end(ab);
1080}
1081
1082/**
1083 * audit_receive_filter - apply all rules to the specified message type
1084 * @type: audit message type
1085 * @pid: target pid for netlink audit messages
1086 * @uid: target uid for netlink audit messages
1087 * @seq: netlink audit message sequence (serial) number
1088 * @data: payload data
1089 * @datasz: size of payload data
1090 * @loginuid: loginuid of sender
1091 * @sessionid: sessionid for netlink audit message
1092 * @sid: SE Linux Security ID of sender
1093 */
1094int audit_receive_filter(int type, int pid, int uid, int seq, void *data,
1095 size_t datasz, uid_t loginuid, u32 sessionid, u32 sid)
1096{
1097 struct task_struct *tsk;
1098 struct audit_netlink_list *dest;
1099 int err = 0;
1100 struct audit_entry *entry;
1101
1102 switch (type) {
1103 case AUDIT_LIST:
1104 case AUDIT_LIST_RULES:
1105 /* We can't just spew out the rules here because we might fill
1106 * the available socket buffer space and deadlock waiting for
1107 * auditctl to read from it... which isn't ever going to
1108 * happen if we're actually running in the context of auditctl
1109 * trying to _send_ the stuff */
1110
1111 dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL);
1112 if (!dest)
1113 return -ENOMEM;
1114 dest->pid = pid;
1115 skb_queue_head_init(&dest->q);
1116
1117 mutex_lock(&audit_filter_mutex);
1118 if (type == AUDIT_LIST)
1119 audit_list(pid, seq, &dest->q);
1120 else
1121 audit_list_rules(pid, seq, &dest->q);
1122 mutex_unlock(&audit_filter_mutex);
1123
1124 tsk = kthread_run(audit_send_list, dest, "audit_send_list");
1125 if (IS_ERR(tsk)) {
1126 skb_queue_purge(&dest->q);
1127 kfree(dest);
1128 err = PTR_ERR(tsk);
1129 }
1130 break;
1131 case AUDIT_ADD:
1132 case AUDIT_ADD_RULE:
1133 if (type == AUDIT_ADD)
1134 entry = audit_rule_to_entry(data);
1135 else
1136 entry = audit_data_to_entry(data, datasz);
1137 if (IS_ERR(entry))
1138 return PTR_ERR(entry);
1139
1140 err = audit_add_rule(entry);
1141 audit_log_rule_change(loginuid, sessionid, sid, "add rule",
1142 &entry->rule, !err);
1143
1144 if (err)
1145 audit_free_rule(entry);
1146 break;
1147 case AUDIT_DEL:
1148 case AUDIT_DEL_RULE:
1149 if (type == AUDIT_DEL)
1150 entry = audit_rule_to_entry(data);
1151 else
1152 entry = audit_data_to_entry(data, datasz);
1153 if (IS_ERR(entry))
1154 return PTR_ERR(entry);
1155
1156 err = audit_del_rule(entry);
1157 audit_log_rule_change(loginuid, sessionid, sid, "remove rule",
1158 &entry->rule, !err);
1159
1160 audit_free_rule(entry);
1161 break;
1162 default:
1163 return -EINVAL;
1164 }
1165
1166 return err;
1167}
1168
1169int audit_comparator(u32 left, u32 op, u32 right)
1170{
1171 switch (op) {
1172 case Audit_equal:
1173 return (left == right);
1174 case Audit_not_equal:
1175 return (left != right);
1176 case Audit_lt:
1177 return (left < right);
1178 case Audit_le:
1179 return (left <= right);
1180 case Audit_gt:
1181 return (left > right);
1182 case Audit_ge:
1183 return (left >= right);
1184 case Audit_bitmask:
1185 return (left & right);
1186 case Audit_bittest:
1187 return ((left & right) == right);
1188 default:
1189 BUG();
1190 return 0;
1191 }
1192}
1193
1194/* Compare given dentry name with last component in given path,
1195 * return of 0 indicates a match. */
1196int audit_compare_dname_path(const char *dname, const char *path,
1197 int *dirlen)
1198{
1199 int dlen, plen;
1200 const char *p;
1201
1202 if (!dname || !path)
1203 return 1;
1204
1205 dlen = strlen(dname);
1206 plen = strlen(path);
1207 if (plen < dlen)
1208 return 1;
1209
1210 /* disregard trailing slashes */
1211 p = path + plen - 1;
1212 while ((*p == '/') && (p > path))
1213 p--;
1214
1215 /* find last path component */
1216 p = p - dlen + 1;
1217 if (p < path)
1218 return 1;
1219 else if (p > path) {
1220 if (*--p != '/')
1221 return 1;
1222 else
1223 p++;
1224 }
1225
1226 /* return length of path's directory component */
1227 if (dirlen)
1228 *dirlen = p - path;
1229 return strncmp(p, dname, dlen);
1230}
1231
1232static int audit_filter_user_rules(struct netlink_skb_parms *cb,
1233 struct audit_krule *rule,
1234 enum audit_state *state)
1235{
1236 int i;
1237
1238 for (i = 0; i < rule->field_count; i++) {
1239 struct audit_field *f = &rule->fields[i];
1240 int result = 0;
1241 u32 sid;
1242
1243 switch (f->type) {
1244 case AUDIT_PID:
1245 result = audit_comparator(cb->creds.pid, f->op, f->val);
1246 break;
1247 case AUDIT_UID:
1248 result = audit_comparator(cb->creds.uid, f->op, f->val);
1249 break;
1250 case AUDIT_GID:
1251 result = audit_comparator(cb->creds.gid, f->op, f->val);
1252 break;
1253 case AUDIT_LOGINUID:
1254 result = audit_comparator(audit_get_loginuid(current),
1255 f->op, f->val);
1256 break;
1257 case AUDIT_SUBJ_USER:
1258 case AUDIT_SUBJ_ROLE:
1259 case AUDIT_SUBJ_TYPE:
1260 case AUDIT_SUBJ_SEN:
1261 case AUDIT_SUBJ_CLR:
1262 if (f->lsm_rule) {
1263 security_task_getsecid(current, &sid);
1264 result = security_audit_rule_match(sid,
1265 f->type,
1266 f->op,
1267 f->lsm_rule,
1268 NULL);
1269 }
1270 break;
1271 }
1272
1273 if (!result)
1274 return 0;
1275 }
1276 switch (rule->action) {
1277 case AUDIT_NEVER: *state = AUDIT_DISABLED; break;
1278 case AUDIT_ALWAYS: *state = AUDIT_RECORD_CONTEXT; break;
1279 }
1280 return 1;
1281}
1282
1283int audit_filter_user(struct netlink_skb_parms *cb)
1284{
1285 enum audit_state state = AUDIT_DISABLED;
1286 struct audit_entry *e;
1287 int ret = 1;
1288
1289 rcu_read_lock();
1290 list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_USER], list) {
1291 if (audit_filter_user_rules(cb, &e->rule, &state)) {
1292 if (state == AUDIT_DISABLED)
1293 ret = 0;
1294 break;
1295 }
1296 }
1297 rcu_read_unlock();
1298
1299 return ret; /* Audit by default */
1300}
1301
1302int audit_filter_type(int type)
1303{
1304 struct audit_entry *e;
1305 int result = 0;
1306
1307 rcu_read_lock();
1308 if (list_empty(&audit_filter_list[AUDIT_FILTER_TYPE]))
1309 goto unlock_and_return;
1310
1311 list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_TYPE],
1312 list) {
1313 int i;
1314 for (i = 0; i < e->rule.field_count; i++) {
1315 struct audit_field *f = &e->rule.fields[i];
1316 if (f->type == AUDIT_MSGTYPE) {
1317 result = audit_comparator(type, f->op, f->val);
1318 if (!result)
1319 break;
1320 }
1321 }
1322 if (result)
1323 goto unlock_and_return;
1324 }
1325unlock_and_return:
1326 rcu_read_unlock();
1327 return result;
1328}
1329
1330static int update_lsm_rule(struct audit_krule *r)
1331{
1332 struct audit_entry *entry = container_of(r, struct audit_entry, rule);
1333 struct audit_entry *nentry;
1334 int err = 0;
1335
1336 if (!security_audit_rule_known(r))
1337 return 0;
1338
1339 nentry = audit_dupe_rule(r);
1340 if (IS_ERR(nentry)) {
1341 /* save the first error encountered for the
1342 * return value */
1343 err = PTR_ERR(nentry);
1344 audit_panic("error updating LSM filters");
1345 if (r->watch)
1346 list_del(&r->rlist);
1347 list_del_rcu(&entry->list);
1348 list_del(&r->list);
1349 } else {
1350 if (r->watch || r->tree)
1351 list_replace_init(&r->rlist, &nentry->rule.rlist);
1352 list_replace_rcu(&entry->list, &nentry->list);
1353 list_replace(&r->list, &nentry->rule.list);
1354 }
1355 call_rcu(&entry->rcu, audit_free_rule_rcu);
1356
1357 return err;
1358}
1359
1360/* This function will re-initialize the lsm_rule field of all applicable rules.
1361 * It will traverse the filter lists serarching for rules that contain LSM
1362 * specific filter fields. When such a rule is found, it is copied, the
1363 * LSM field is re-initialized, and the old rule is replaced with the
1364 * updated rule. */
1365int audit_update_lsm_rules(void)
1366{
1367 struct audit_krule *r, *n;
1368 int i, err = 0;
1369
1370 /* audit_filter_mutex synchronizes the writers */
1371 mutex_lock(&audit_filter_mutex);
1372
1373 for (i = 0; i < AUDIT_NR_FILTERS; i++) {
1374 list_for_each_entry_safe(r, n, &audit_rules_list[i], list) {
1375 int res = update_lsm_rule(r);
1376 if (!err)
1377 err = res;
1378 }
1379 }
1380 mutex_unlock(&audit_filter_mutex);
1381
1382 return err;
1383}