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1/* auditfilter.c -- filtering of audit events
2 *
3 * Copyright 2003-2004 Red Hat, Inc.
4 * Copyright 2005 Hewlett-Packard Development Company, L.P.
5 * Copyright 2005 IBM Corporation
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 */
21
22#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
23
24#include <linux/kernel.h>
25#include <linux/audit.h>
26#include <linux/kthread.h>
27#include <linux/mutex.h>
28#include <linux/fs.h>
29#include <linux/namei.h>
30#include <linux/netlink.h>
31#include <linux/sched.h>
32#include <linux/slab.h>
33#include <linux/security.h>
34#include <net/net_namespace.h>
35#include <net/sock.h>
36#include "audit.h"
37
38/*
39 * Locking model:
40 *
41 * audit_filter_mutex:
42 * Synchronizes writes and blocking reads of audit's filterlist
43 * data. Rcu is used to traverse the filterlist and access
44 * contents of structs audit_entry, audit_watch and opaque
45 * LSM rules during filtering. If modified, these structures
46 * must be copied and replace their counterparts in the filterlist.
47 * An audit_parent struct is not accessed during filtering, so may
48 * be written directly provided audit_filter_mutex is held.
49 */
50
51/* Audit filter lists, defined in <linux/audit.h> */
52struct list_head audit_filter_list[AUDIT_NR_FILTERS] = {
53 LIST_HEAD_INIT(audit_filter_list[0]),
54 LIST_HEAD_INIT(audit_filter_list[1]),
55 LIST_HEAD_INIT(audit_filter_list[2]),
56 LIST_HEAD_INIT(audit_filter_list[3]),
57 LIST_HEAD_INIT(audit_filter_list[4]),
58 LIST_HEAD_INIT(audit_filter_list[5]),
59 LIST_HEAD_INIT(audit_filter_list[6]),
60#if AUDIT_NR_FILTERS != 7
61#error Fix audit_filter_list initialiser
62#endif
63};
64static struct list_head audit_rules_list[AUDIT_NR_FILTERS] = {
65 LIST_HEAD_INIT(audit_rules_list[0]),
66 LIST_HEAD_INIT(audit_rules_list[1]),
67 LIST_HEAD_INIT(audit_rules_list[2]),
68 LIST_HEAD_INIT(audit_rules_list[3]),
69 LIST_HEAD_INIT(audit_rules_list[4]),
70 LIST_HEAD_INIT(audit_rules_list[5]),
71 LIST_HEAD_INIT(audit_rules_list[6]),
72};
73
74DEFINE_MUTEX(audit_filter_mutex);
75
76static void audit_free_lsm_field(struct audit_field *f)
77{
78 switch (f->type) {
79 case AUDIT_SUBJ_USER:
80 case AUDIT_SUBJ_ROLE:
81 case AUDIT_SUBJ_TYPE:
82 case AUDIT_SUBJ_SEN:
83 case AUDIT_SUBJ_CLR:
84 case AUDIT_OBJ_USER:
85 case AUDIT_OBJ_ROLE:
86 case AUDIT_OBJ_TYPE:
87 case AUDIT_OBJ_LEV_LOW:
88 case AUDIT_OBJ_LEV_HIGH:
89 kfree(f->lsm_str);
90 security_audit_rule_free(f->lsm_rule);
91 }
92}
93
94static inline void audit_free_rule(struct audit_entry *e)
95{
96 int i;
97 struct audit_krule *erule = &e->rule;
98
99 /* some rules don't have associated watches */
100 if (erule->watch)
101 audit_put_watch(erule->watch);
102 if (erule->fields)
103 for (i = 0; i < erule->field_count; i++)
104 audit_free_lsm_field(&erule->fields[i]);
105 kfree(erule->fields);
106 kfree(erule->filterkey);
107 kfree(e);
108}
109
110void audit_free_rule_rcu(struct rcu_head *head)
111{
112 struct audit_entry *e = container_of(head, struct audit_entry, rcu);
113 audit_free_rule(e);
114}
115
116/* Initialize an audit filterlist entry. */
117static inline struct audit_entry *audit_init_entry(u32 field_count)
118{
119 struct audit_entry *entry;
120 struct audit_field *fields;
121
122 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
123 if (unlikely(!entry))
124 return NULL;
125
126 fields = kcalloc(field_count, sizeof(*fields), GFP_KERNEL);
127 if (unlikely(!fields)) {
128 kfree(entry);
129 return NULL;
130 }
131 entry->rule.fields = fields;
132
133 return entry;
134}
135
136/* Unpack a filter field's string representation from user-space
137 * buffer. */
138char *audit_unpack_string(void **bufp, size_t *remain, size_t len)
139{
140 char *str;
141
142 if (!*bufp || (len == 0) || (len > *remain))
143 return ERR_PTR(-EINVAL);
144
145 /* Of the currently implemented string fields, PATH_MAX
146 * defines the longest valid length.
147 */
148 if (len > PATH_MAX)
149 return ERR_PTR(-ENAMETOOLONG);
150
151 str = kmalloc(len + 1, GFP_KERNEL);
152 if (unlikely(!str))
153 return ERR_PTR(-ENOMEM);
154
155 memcpy(str, *bufp, len);
156 str[len] = 0;
157 *bufp += len;
158 *remain -= len;
159
160 return str;
161}
162
163/* Translate an inode field to kernel representation. */
164static inline int audit_to_inode(struct audit_krule *krule,
165 struct audit_field *f)
166{
167 if (krule->listnr != AUDIT_FILTER_EXIT ||
168 krule->inode_f || krule->watch || krule->tree ||
169 (f->op != Audit_equal && f->op != Audit_not_equal))
170 return -EINVAL;
171
172 krule->inode_f = f;
173 return 0;
174}
175
176static __u32 *classes[AUDIT_SYSCALL_CLASSES];
177
178int __init audit_register_class(int class, unsigned *list)
179{
180 __u32 *p = kcalloc(AUDIT_BITMASK_SIZE, sizeof(__u32), GFP_KERNEL);
181 if (!p)
182 return -ENOMEM;
183 while (*list != ~0U) {
184 unsigned n = *list++;
185 if (n >= AUDIT_BITMASK_SIZE * 32 - AUDIT_SYSCALL_CLASSES) {
186 kfree(p);
187 return -EINVAL;
188 }
189 p[AUDIT_WORD(n)] |= AUDIT_BIT(n);
190 }
191 if (class >= AUDIT_SYSCALL_CLASSES || classes[class]) {
192 kfree(p);
193 return -EINVAL;
194 }
195 classes[class] = p;
196 return 0;
197}
198
199int audit_match_class(int class, unsigned syscall)
200{
201 if (unlikely(syscall >= AUDIT_BITMASK_SIZE * 32))
202 return 0;
203 if (unlikely(class >= AUDIT_SYSCALL_CLASSES || !classes[class]))
204 return 0;
205 return classes[class][AUDIT_WORD(syscall)] & AUDIT_BIT(syscall);
206}
207
208#ifdef CONFIG_AUDITSYSCALL
209static inline int audit_match_class_bits(int class, u32 *mask)
210{
211 int i;
212
213 if (classes[class]) {
214 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
215 if (mask[i] & classes[class][i])
216 return 0;
217 }
218 return 1;
219}
220
221static int audit_match_signal(struct audit_entry *entry)
222{
223 struct audit_field *arch = entry->rule.arch_f;
224
225 if (!arch) {
226 /* When arch is unspecified, we must check both masks on biarch
227 * as syscall number alone is ambiguous. */
228 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
229 entry->rule.mask) &&
230 audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
231 entry->rule.mask));
232 }
233
234 switch(audit_classify_arch(arch->val)) {
235 case 0: /* native */
236 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
237 entry->rule.mask));
238 case 1: /* 32bit on biarch */
239 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
240 entry->rule.mask));
241 default:
242 return 1;
243 }
244}
245#endif
246
247/* Common user-space to kernel rule translation. */
248static inline struct audit_entry *audit_to_entry_common(struct audit_rule_data *rule)
249{
250 unsigned listnr;
251 struct audit_entry *entry;
252 int i, err;
253
254 err = -EINVAL;
255 listnr = rule->flags & ~AUDIT_FILTER_PREPEND;
256 switch(listnr) {
257 default:
258 goto exit_err;
259#ifdef CONFIG_AUDITSYSCALL
260 case AUDIT_FILTER_ENTRY:
261 pr_err("AUDIT_FILTER_ENTRY is deprecated\n");
262 goto exit_err;
263 case AUDIT_FILTER_EXIT:
264 case AUDIT_FILTER_TASK:
265#endif
266 case AUDIT_FILTER_USER:
267 case AUDIT_FILTER_TYPE:
268 case AUDIT_FILTER_FS:
269 ;
270 }
271 if (unlikely(rule->action == AUDIT_POSSIBLE)) {
272 pr_err("AUDIT_POSSIBLE is deprecated\n");
273 goto exit_err;
274 }
275 if (rule->action != AUDIT_NEVER && rule->action != AUDIT_ALWAYS)
276 goto exit_err;
277 if (rule->field_count > AUDIT_MAX_FIELDS)
278 goto exit_err;
279
280 err = -ENOMEM;
281 entry = audit_init_entry(rule->field_count);
282 if (!entry)
283 goto exit_err;
284
285 entry->rule.flags = rule->flags & AUDIT_FILTER_PREPEND;
286 entry->rule.listnr = listnr;
287 entry->rule.action = rule->action;
288 entry->rule.field_count = rule->field_count;
289
290 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
291 entry->rule.mask[i] = rule->mask[i];
292
293 for (i = 0; i < AUDIT_SYSCALL_CLASSES; i++) {
294 int bit = AUDIT_BITMASK_SIZE * 32 - i - 1;
295 __u32 *p = &entry->rule.mask[AUDIT_WORD(bit)];
296 __u32 *class;
297
298 if (!(*p & AUDIT_BIT(bit)))
299 continue;
300 *p &= ~AUDIT_BIT(bit);
301 class = classes[i];
302 if (class) {
303 int j;
304 for (j = 0; j < AUDIT_BITMASK_SIZE; j++)
305 entry->rule.mask[j] |= class[j];
306 }
307 }
308
309 return entry;
310
311exit_err:
312 return ERR_PTR(err);
313}
314
315static u32 audit_ops[] =
316{
317 [Audit_equal] = AUDIT_EQUAL,
318 [Audit_not_equal] = AUDIT_NOT_EQUAL,
319 [Audit_bitmask] = AUDIT_BIT_MASK,
320 [Audit_bittest] = AUDIT_BIT_TEST,
321 [Audit_lt] = AUDIT_LESS_THAN,
322 [Audit_gt] = AUDIT_GREATER_THAN,
323 [Audit_le] = AUDIT_LESS_THAN_OR_EQUAL,
324 [Audit_ge] = AUDIT_GREATER_THAN_OR_EQUAL,
325};
326
327static u32 audit_to_op(u32 op)
328{
329 u32 n;
330 for (n = Audit_equal; n < Audit_bad && audit_ops[n] != op; n++)
331 ;
332 return n;
333}
334
335/* check if an audit field is valid */
336static int audit_field_valid(struct audit_entry *entry, struct audit_field *f)
337{
338 switch(f->type) {
339 case AUDIT_MSGTYPE:
340 if (entry->rule.listnr != AUDIT_FILTER_TYPE &&
341 entry->rule.listnr != AUDIT_FILTER_USER)
342 return -EINVAL;
343 break;
344 case AUDIT_FSTYPE:
345 if (entry->rule.listnr != AUDIT_FILTER_FS)
346 return -EINVAL;
347 break;
348 }
349
350 switch(entry->rule.listnr) {
351 case AUDIT_FILTER_FS:
352 switch(f->type) {
353 case AUDIT_FSTYPE:
354 case AUDIT_FILTERKEY:
355 break;
356 default:
357 return -EINVAL;
358 }
359 }
360
361 switch(f->type) {
362 default:
363 return -EINVAL;
364 case AUDIT_UID:
365 case AUDIT_EUID:
366 case AUDIT_SUID:
367 case AUDIT_FSUID:
368 case AUDIT_LOGINUID:
369 case AUDIT_OBJ_UID:
370 case AUDIT_GID:
371 case AUDIT_EGID:
372 case AUDIT_SGID:
373 case AUDIT_FSGID:
374 case AUDIT_OBJ_GID:
375 case AUDIT_PID:
376 case AUDIT_PERS:
377 case AUDIT_MSGTYPE:
378 case AUDIT_PPID:
379 case AUDIT_DEVMAJOR:
380 case AUDIT_DEVMINOR:
381 case AUDIT_EXIT:
382 case AUDIT_SUCCESS:
383 case AUDIT_INODE:
384 case AUDIT_SESSIONID:
385 /* bit ops are only useful on syscall args */
386 if (f->op == Audit_bitmask || f->op == Audit_bittest)
387 return -EINVAL;
388 break;
389 case AUDIT_ARG0:
390 case AUDIT_ARG1:
391 case AUDIT_ARG2:
392 case AUDIT_ARG3:
393 case AUDIT_SUBJ_USER:
394 case AUDIT_SUBJ_ROLE:
395 case AUDIT_SUBJ_TYPE:
396 case AUDIT_SUBJ_SEN:
397 case AUDIT_SUBJ_CLR:
398 case AUDIT_OBJ_USER:
399 case AUDIT_OBJ_ROLE:
400 case AUDIT_OBJ_TYPE:
401 case AUDIT_OBJ_LEV_LOW:
402 case AUDIT_OBJ_LEV_HIGH:
403 case AUDIT_WATCH:
404 case AUDIT_DIR:
405 case AUDIT_FILTERKEY:
406 break;
407 case AUDIT_LOGINUID_SET:
408 if ((f->val != 0) && (f->val != 1))
409 return -EINVAL;
410 /* FALL THROUGH */
411 case AUDIT_ARCH:
412 case AUDIT_FSTYPE:
413 if (f->op != Audit_not_equal && f->op != Audit_equal)
414 return -EINVAL;
415 break;
416 case AUDIT_PERM:
417 if (f->val & ~15)
418 return -EINVAL;
419 break;
420 case AUDIT_FILETYPE:
421 if (f->val & ~S_IFMT)
422 return -EINVAL;
423 break;
424 case AUDIT_FIELD_COMPARE:
425 if (f->val > AUDIT_MAX_FIELD_COMPARE)
426 return -EINVAL;
427 break;
428 case AUDIT_EXE:
429 if (f->op != Audit_equal)
430 return -EINVAL;
431 if (entry->rule.listnr != AUDIT_FILTER_EXIT)
432 return -EINVAL;
433 break;
434 }
435 return 0;
436}
437
438/* Translate struct audit_rule_data to kernel's rule representation. */
439static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
440 size_t datasz)
441{
442 int err = 0;
443 struct audit_entry *entry;
444 void *bufp;
445 size_t remain = datasz - sizeof(struct audit_rule_data);
446 int i;
447 char *str;
448 struct audit_fsnotify_mark *audit_mark;
449
450 entry = audit_to_entry_common(data);
451 if (IS_ERR(entry))
452 goto exit_nofree;
453
454 bufp = data->buf;
455 for (i = 0; i < data->field_count; i++) {
456 struct audit_field *f = &entry->rule.fields[i];
457
458 err = -EINVAL;
459
460 f->op = audit_to_op(data->fieldflags[i]);
461 if (f->op == Audit_bad)
462 goto exit_free;
463
464 f->type = data->fields[i];
465 f->val = data->values[i];
466
467 /* Support legacy tests for a valid loginuid */
468 if ((f->type == AUDIT_LOGINUID) && (f->val == AUDIT_UID_UNSET)) {
469 f->type = AUDIT_LOGINUID_SET;
470 f->val = 0;
471 entry->rule.pflags |= AUDIT_LOGINUID_LEGACY;
472 }
473
474 err = audit_field_valid(entry, f);
475 if (err)
476 goto exit_free;
477
478 err = -EINVAL;
479 switch (f->type) {
480 case AUDIT_LOGINUID:
481 case AUDIT_UID:
482 case AUDIT_EUID:
483 case AUDIT_SUID:
484 case AUDIT_FSUID:
485 case AUDIT_OBJ_UID:
486 f->uid = make_kuid(current_user_ns(), f->val);
487 if (!uid_valid(f->uid))
488 goto exit_free;
489 break;
490 case AUDIT_GID:
491 case AUDIT_EGID:
492 case AUDIT_SGID:
493 case AUDIT_FSGID:
494 case AUDIT_OBJ_GID:
495 f->gid = make_kgid(current_user_ns(), f->val);
496 if (!gid_valid(f->gid))
497 goto exit_free;
498 break;
499 case AUDIT_ARCH:
500 entry->rule.arch_f = f;
501 break;
502 case AUDIT_SUBJ_USER:
503 case AUDIT_SUBJ_ROLE:
504 case AUDIT_SUBJ_TYPE:
505 case AUDIT_SUBJ_SEN:
506 case AUDIT_SUBJ_CLR:
507 case AUDIT_OBJ_USER:
508 case AUDIT_OBJ_ROLE:
509 case AUDIT_OBJ_TYPE:
510 case AUDIT_OBJ_LEV_LOW:
511 case AUDIT_OBJ_LEV_HIGH:
512 str = audit_unpack_string(&bufp, &remain, f->val);
513 if (IS_ERR(str))
514 goto exit_free;
515 entry->rule.buflen += f->val;
516
517 err = security_audit_rule_init(f->type, f->op, str,
518 (void **)&f->lsm_rule);
519 /* Keep currently invalid fields around in case they
520 * become valid after a policy reload. */
521 if (err == -EINVAL) {
522 pr_warn("audit rule for LSM \'%s\' is invalid\n",
523 str);
524 err = 0;
525 }
526 if (err) {
527 kfree(str);
528 goto exit_free;
529 } else
530 f->lsm_str = str;
531 break;
532 case AUDIT_WATCH:
533 str = audit_unpack_string(&bufp, &remain, f->val);
534 if (IS_ERR(str))
535 goto exit_free;
536 entry->rule.buflen += f->val;
537
538 err = audit_to_watch(&entry->rule, str, f->val, f->op);
539 if (err) {
540 kfree(str);
541 goto exit_free;
542 }
543 break;
544 case AUDIT_DIR:
545 str = audit_unpack_string(&bufp, &remain, f->val);
546 if (IS_ERR(str))
547 goto exit_free;
548 entry->rule.buflen += f->val;
549
550 err = audit_make_tree(&entry->rule, str, f->op);
551 kfree(str);
552 if (err)
553 goto exit_free;
554 break;
555 case AUDIT_INODE:
556 err = audit_to_inode(&entry->rule, f);
557 if (err)
558 goto exit_free;
559 break;
560 case AUDIT_FILTERKEY:
561 if (entry->rule.filterkey || f->val > AUDIT_MAX_KEY_LEN)
562 goto exit_free;
563 str = audit_unpack_string(&bufp, &remain, f->val);
564 if (IS_ERR(str))
565 goto exit_free;
566 entry->rule.buflen += f->val;
567 entry->rule.filterkey = str;
568 break;
569 case AUDIT_EXE:
570 if (entry->rule.exe || f->val > PATH_MAX)
571 goto exit_free;
572 str = audit_unpack_string(&bufp, &remain, f->val);
573 if (IS_ERR(str)) {
574 err = PTR_ERR(str);
575 goto exit_free;
576 }
577 entry->rule.buflen += f->val;
578
579 audit_mark = audit_alloc_mark(&entry->rule, str, f->val);
580 if (IS_ERR(audit_mark)) {
581 kfree(str);
582 err = PTR_ERR(audit_mark);
583 goto exit_free;
584 }
585 entry->rule.exe = audit_mark;
586 break;
587 }
588 }
589
590 if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal)
591 entry->rule.inode_f = NULL;
592
593exit_nofree:
594 return entry;
595
596exit_free:
597 if (entry->rule.tree)
598 audit_put_tree(entry->rule.tree); /* that's the temporary one */
599 if (entry->rule.exe)
600 audit_remove_mark(entry->rule.exe); /* that's the template one */
601 audit_free_rule(entry);
602 return ERR_PTR(err);
603}
604
605/* Pack a filter field's string representation into data block. */
606static inline size_t audit_pack_string(void **bufp, const char *str)
607{
608 size_t len = strlen(str);
609
610 memcpy(*bufp, str, len);
611 *bufp += len;
612
613 return len;
614}
615
616/* Translate kernel rule representation to struct audit_rule_data. */
617static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule)
618{
619 struct audit_rule_data *data;
620 void *bufp;
621 int i;
622
623 data = kmalloc(sizeof(*data) + krule->buflen, GFP_KERNEL);
624 if (unlikely(!data))
625 return NULL;
626 memset(data, 0, sizeof(*data));
627
628 data->flags = krule->flags | krule->listnr;
629 data->action = krule->action;
630 data->field_count = krule->field_count;
631 bufp = data->buf;
632 for (i = 0; i < data->field_count; i++) {
633 struct audit_field *f = &krule->fields[i];
634
635 data->fields[i] = f->type;
636 data->fieldflags[i] = audit_ops[f->op];
637 switch(f->type) {
638 case AUDIT_SUBJ_USER:
639 case AUDIT_SUBJ_ROLE:
640 case AUDIT_SUBJ_TYPE:
641 case AUDIT_SUBJ_SEN:
642 case AUDIT_SUBJ_CLR:
643 case AUDIT_OBJ_USER:
644 case AUDIT_OBJ_ROLE:
645 case AUDIT_OBJ_TYPE:
646 case AUDIT_OBJ_LEV_LOW:
647 case AUDIT_OBJ_LEV_HIGH:
648 data->buflen += data->values[i] =
649 audit_pack_string(&bufp, f->lsm_str);
650 break;
651 case AUDIT_WATCH:
652 data->buflen += data->values[i] =
653 audit_pack_string(&bufp,
654 audit_watch_path(krule->watch));
655 break;
656 case AUDIT_DIR:
657 data->buflen += data->values[i] =
658 audit_pack_string(&bufp,
659 audit_tree_path(krule->tree));
660 break;
661 case AUDIT_FILTERKEY:
662 data->buflen += data->values[i] =
663 audit_pack_string(&bufp, krule->filterkey);
664 break;
665 case AUDIT_EXE:
666 data->buflen += data->values[i] =
667 audit_pack_string(&bufp, audit_mark_path(krule->exe));
668 break;
669 case AUDIT_LOGINUID_SET:
670 if (krule->pflags & AUDIT_LOGINUID_LEGACY && !f->val) {
671 data->fields[i] = AUDIT_LOGINUID;
672 data->values[i] = AUDIT_UID_UNSET;
673 break;
674 }
675 /* fallthrough if set */
676 default:
677 data->values[i] = f->val;
678 }
679 }
680 for (i = 0; i < AUDIT_BITMASK_SIZE; i++) data->mask[i] = krule->mask[i];
681
682 return data;
683}
684
685/* Compare two rules in kernel format. Considered success if rules
686 * don't match. */
687static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
688{
689 int i;
690
691 if (a->flags != b->flags ||
692 a->pflags != b->pflags ||
693 a->listnr != b->listnr ||
694 a->action != b->action ||
695 a->field_count != b->field_count)
696 return 1;
697
698 for (i = 0; i < a->field_count; i++) {
699 if (a->fields[i].type != b->fields[i].type ||
700 a->fields[i].op != b->fields[i].op)
701 return 1;
702
703 switch(a->fields[i].type) {
704 case AUDIT_SUBJ_USER:
705 case AUDIT_SUBJ_ROLE:
706 case AUDIT_SUBJ_TYPE:
707 case AUDIT_SUBJ_SEN:
708 case AUDIT_SUBJ_CLR:
709 case AUDIT_OBJ_USER:
710 case AUDIT_OBJ_ROLE:
711 case AUDIT_OBJ_TYPE:
712 case AUDIT_OBJ_LEV_LOW:
713 case AUDIT_OBJ_LEV_HIGH:
714 if (strcmp(a->fields[i].lsm_str, b->fields[i].lsm_str))
715 return 1;
716 break;
717 case AUDIT_WATCH:
718 if (strcmp(audit_watch_path(a->watch),
719 audit_watch_path(b->watch)))
720 return 1;
721 break;
722 case AUDIT_DIR:
723 if (strcmp(audit_tree_path(a->tree),
724 audit_tree_path(b->tree)))
725 return 1;
726 break;
727 case AUDIT_FILTERKEY:
728 /* both filterkeys exist based on above type compare */
729 if (strcmp(a->filterkey, b->filterkey))
730 return 1;
731 break;
732 case AUDIT_EXE:
733 /* both paths exist based on above type compare */
734 if (strcmp(audit_mark_path(a->exe),
735 audit_mark_path(b->exe)))
736 return 1;
737 break;
738 case AUDIT_UID:
739 case AUDIT_EUID:
740 case AUDIT_SUID:
741 case AUDIT_FSUID:
742 case AUDIT_LOGINUID:
743 case AUDIT_OBJ_UID:
744 if (!uid_eq(a->fields[i].uid, b->fields[i].uid))
745 return 1;
746 break;
747 case AUDIT_GID:
748 case AUDIT_EGID:
749 case AUDIT_SGID:
750 case AUDIT_FSGID:
751 case AUDIT_OBJ_GID:
752 if (!gid_eq(a->fields[i].gid, b->fields[i].gid))
753 return 1;
754 break;
755 default:
756 if (a->fields[i].val != b->fields[i].val)
757 return 1;
758 }
759 }
760
761 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
762 if (a->mask[i] != b->mask[i])
763 return 1;
764
765 return 0;
766}
767
768/* Duplicate LSM field information. The lsm_rule is opaque, so must be
769 * re-initialized. */
770static inline int audit_dupe_lsm_field(struct audit_field *df,
771 struct audit_field *sf)
772{
773 int ret = 0;
774 char *lsm_str;
775
776 /* our own copy of lsm_str */
777 lsm_str = kstrdup(sf->lsm_str, GFP_KERNEL);
778 if (unlikely(!lsm_str))
779 return -ENOMEM;
780 df->lsm_str = lsm_str;
781
782 /* our own (refreshed) copy of lsm_rule */
783 ret = security_audit_rule_init(df->type, df->op, df->lsm_str,
784 (void **)&df->lsm_rule);
785 /* Keep currently invalid fields around in case they
786 * become valid after a policy reload. */
787 if (ret == -EINVAL) {
788 pr_warn("audit rule for LSM \'%s\' is invalid\n",
789 df->lsm_str);
790 ret = 0;
791 }
792
793 return ret;
794}
795
796/* Duplicate an audit rule. This will be a deep copy with the exception
797 * of the watch - that pointer is carried over. The LSM specific fields
798 * will be updated in the copy. The point is to be able to replace the old
799 * rule with the new rule in the filterlist, then free the old rule.
800 * The rlist element is undefined; list manipulations are handled apart from
801 * the initial copy. */
802struct audit_entry *audit_dupe_rule(struct audit_krule *old)
803{
804 u32 fcount = old->field_count;
805 struct audit_entry *entry;
806 struct audit_krule *new;
807 char *fk;
808 int i, err = 0;
809
810 entry = audit_init_entry(fcount);
811 if (unlikely(!entry))
812 return ERR_PTR(-ENOMEM);
813
814 new = &entry->rule;
815 new->flags = old->flags;
816 new->pflags = old->pflags;
817 new->listnr = old->listnr;
818 new->action = old->action;
819 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
820 new->mask[i] = old->mask[i];
821 new->prio = old->prio;
822 new->buflen = old->buflen;
823 new->inode_f = old->inode_f;
824 new->field_count = old->field_count;
825
826 /*
827 * note that we are OK with not refcounting here; audit_match_tree()
828 * never dereferences tree and we can't get false positives there
829 * since we'd have to have rule gone from the list *and* removed
830 * before the chunks found by lookup had been allocated, i.e. before
831 * the beginning of list scan.
832 */
833 new->tree = old->tree;
834 memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount);
835
836 /* deep copy this information, updating the lsm_rule fields, because
837 * the originals will all be freed when the old rule is freed. */
838 for (i = 0; i < fcount; i++) {
839 switch (new->fields[i].type) {
840 case AUDIT_SUBJ_USER:
841 case AUDIT_SUBJ_ROLE:
842 case AUDIT_SUBJ_TYPE:
843 case AUDIT_SUBJ_SEN:
844 case AUDIT_SUBJ_CLR:
845 case AUDIT_OBJ_USER:
846 case AUDIT_OBJ_ROLE:
847 case AUDIT_OBJ_TYPE:
848 case AUDIT_OBJ_LEV_LOW:
849 case AUDIT_OBJ_LEV_HIGH:
850 err = audit_dupe_lsm_field(&new->fields[i],
851 &old->fields[i]);
852 break;
853 case AUDIT_FILTERKEY:
854 fk = kstrdup(old->filterkey, GFP_KERNEL);
855 if (unlikely(!fk))
856 err = -ENOMEM;
857 else
858 new->filterkey = fk;
859 break;
860 case AUDIT_EXE:
861 err = audit_dupe_exe(new, old);
862 break;
863 }
864 if (err) {
865 if (new->exe)
866 audit_remove_mark(new->exe);
867 audit_free_rule(entry);
868 return ERR_PTR(err);
869 }
870 }
871
872 if (old->watch) {
873 audit_get_watch(old->watch);
874 new->watch = old->watch;
875 }
876
877 return entry;
878}
879
880/* Find an existing audit rule.
881 * Caller must hold audit_filter_mutex to prevent stale rule data. */
882static struct audit_entry *audit_find_rule(struct audit_entry *entry,
883 struct list_head **p)
884{
885 struct audit_entry *e, *found = NULL;
886 struct list_head *list;
887 int h;
888
889 if (entry->rule.inode_f) {
890 h = audit_hash_ino(entry->rule.inode_f->val);
891 *p = list = &audit_inode_hash[h];
892 } else if (entry->rule.watch) {
893 /* we don't know the inode number, so must walk entire hash */
894 for (h = 0; h < AUDIT_INODE_BUCKETS; h++) {
895 list = &audit_inode_hash[h];
896 list_for_each_entry(e, list, list)
897 if (!audit_compare_rule(&entry->rule, &e->rule)) {
898 found = e;
899 goto out;
900 }
901 }
902 goto out;
903 } else {
904 *p = list = &audit_filter_list[entry->rule.listnr];
905 }
906
907 list_for_each_entry(e, list, list)
908 if (!audit_compare_rule(&entry->rule, &e->rule)) {
909 found = e;
910 goto out;
911 }
912
913out:
914 return found;
915}
916
917static u64 prio_low = ~0ULL/2;
918static u64 prio_high = ~0ULL/2 - 1;
919
920/* Add rule to given filterlist if not a duplicate. */
921static inline int audit_add_rule(struct audit_entry *entry)
922{
923 struct audit_entry *e;
924 struct audit_watch *watch = entry->rule.watch;
925 struct audit_tree *tree = entry->rule.tree;
926 struct list_head *list;
927 int err = 0;
928#ifdef CONFIG_AUDITSYSCALL
929 int dont_count = 0;
930
931 /* If any of these, don't count towards total */
932 switch(entry->rule.listnr) {
933 case AUDIT_FILTER_USER:
934 case AUDIT_FILTER_TYPE:
935 case AUDIT_FILTER_FS:
936 dont_count = 1;
937 }
938#endif
939
940 mutex_lock(&audit_filter_mutex);
941 e = audit_find_rule(entry, &list);
942 if (e) {
943 mutex_unlock(&audit_filter_mutex);
944 err = -EEXIST;
945 /* normally audit_add_tree_rule() will free it on failure */
946 if (tree)
947 audit_put_tree(tree);
948 return err;
949 }
950
951 if (watch) {
952 /* audit_filter_mutex is dropped and re-taken during this call */
953 err = audit_add_watch(&entry->rule, &list);
954 if (err) {
955 mutex_unlock(&audit_filter_mutex);
956 /*
957 * normally audit_add_tree_rule() will free it
958 * on failure
959 */
960 if (tree)
961 audit_put_tree(tree);
962 return err;
963 }
964 }
965 if (tree) {
966 err = audit_add_tree_rule(&entry->rule);
967 if (err) {
968 mutex_unlock(&audit_filter_mutex);
969 return err;
970 }
971 }
972
973 entry->rule.prio = ~0ULL;
974 if (entry->rule.listnr == AUDIT_FILTER_EXIT) {
975 if (entry->rule.flags & AUDIT_FILTER_PREPEND)
976 entry->rule.prio = ++prio_high;
977 else
978 entry->rule.prio = --prio_low;
979 }
980
981 if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
982 list_add(&entry->rule.list,
983 &audit_rules_list[entry->rule.listnr]);
984 list_add_rcu(&entry->list, list);
985 entry->rule.flags &= ~AUDIT_FILTER_PREPEND;
986 } else {
987 list_add_tail(&entry->rule.list,
988 &audit_rules_list[entry->rule.listnr]);
989 list_add_tail_rcu(&entry->list, list);
990 }
991#ifdef CONFIG_AUDITSYSCALL
992 if (!dont_count)
993 audit_n_rules++;
994
995 if (!audit_match_signal(entry))
996 audit_signals++;
997#endif
998 mutex_unlock(&audit_filter_mutex);
999
1000 return err;
1001}
1002
1003/* Remove an existing rule from filterlist. */
1004int audit_del_rule(struct audit_entry *entry)
1005{
1006 struct audit_entry *e;
1007 struct audit_tree *tree = entry->rule.tree;
1008 struct list_head *list;
1009 int ret = 0;
1010#ifdef CONFIG_AUDITSYSCALL
1011 int dont_count = 0;
1012
1013 /* If any of these, don't count towards total */
1014 switch(entry->rule.listnr) {
1015 case AUDIT_FILTER_USER:
1016 case AUDIT_FILTER_TYPE:
1017 case AUDIT_FILTER_FS:
1018 dont_count = 1;
1019 }
1020#endif
1021
1022 mutex_lock(&audit_filter_mutex);
1023 e = audit_find_rule(entry, &list);
1024 if (!e) {
1025 ret = -ENOENT;
1026 goto out;
1027 }
1028
1029 if (e->rule.watch)
1030 audit_remove_watch_rule(&e->rule);
1031
1032 if (e->rule.tree)
1033 audit_remove_tree_rule(&e->rule);
1034
1035 if (e->rule.exe)
1036 audit_remove_mark_rule(&e->rule);
1037
1038#ifdef CONFIG_AUDITSYSCALL
1039 if (!dont_count)
1040 audit_n_rules--;
1041
1042 if (!audit_match_signal(entry))
1043 audit_signals--;
1044#endif
1045
1046 list_del_rcu(&e->list);
1047 list_del(&e->rule.list);
1048 call_rcu(&e->rcu, audit_free_rule_rcu);
1049
1050out:
1051 mutex_unlock(&audit_filter_mutex);
1052
1053 if (tree)
1054 audit_put_tree(tree); /* that's the temporary one */
1055
1056 return ret;
1057}
1058
1059/* List rules using struct audit_rule_data. */
1060static void audit_list_rules(int seq, struct sk_buff_head *q)
1061{
1062 struct sk_buff *skb;
1063 struct audit_krule *r;
1064 int i;
1065
1066 /* This is a blocking read, so use audit_filter_mutex instead of rcu
1067 * iterator to sync with list writers. */
1068 for (i=0; i<AUDIT_NR_FILTERS; i++) {
1069 list_for_each_entry(r, &audit_rules_list[i], list) {
1070 struct audit_rule_data *data;
1071
1072 data = audit_krule_to_data(r);
1073 if (unlikely(!data))
1074 break;
1075 skb = audit_make_reply(seq, AUDIT_LIST_RULES, 0, 1,
1076 data,
1077 sizeof(*data) + data->buflen);
1078 if (skb)
1079 skb_queue_tail(q, skb);
1080 kfree(data);
1081 }
1082 }
1083 skb = audit_make_reply(seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);
1084 if (skb)
1085 skb_queue_tail(q, skb);
1086}
1087
1088/* Log rule additions and removals */
1089static void audit_log_rule_change(char *action, struct audit_krule *rule, int res)
1090{
1091 struct audit_buffer *ab;
1092 uid_t loginuid = from_kuid(&init_user_ns, audit_get_loginuid(current));
1093 unsigned int sessionid = audit_get_sessionid(current);
1094
1095 if (!audit_enabled)
1096 return;
1097
1098 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
1099 if (!ab)
1100 return;
1101 audit_log_format(ab, "auid=%u ses=%u" ,loginuid, sessionid);
1102 audit_log_task_context(ab);
1103 audit_log_format(ab, " op=%s", action);
1104 audit_log_key(ab, rule->filterkey);
1105 audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
1106 audit_log_end(ab);
1107}
1108
1109/**
1110 * audit_rule_change - apply all rules to the specified message type
1111 * @type: audit message type
1112 * @seq: netlink audit message sequence (serial) number
1113 * @data: payload data
1114 * @datasz: size of payload data
1115 */
1116int audit_rule_change(int type, int seq, void *data, size_t datasz)
1117{
1118 int err = 0;
1119 struct audit_entry *entry;
1120
1121 entry = audit_data_to_entry(data, datasz);
1122 if (IS_ERR(entry))
1123 return PTR_ERR(entry);
1124
1125 switch (type) {
1126 case AUDIT_ADD_RULE:
1127 err = audit_add_rule(entry);
1128 audit_log_rule_change("add_rule", &entry->rule, !err);
1129 break;
1130 case AUDIT_DEL_RULE:
1131 err = audit_del_rule(entry);
1132 audit_log_rule_change("remove_rule", &entry->rule, !err);
1133 break;
1134 default:
1135 err = -EINVAL;
1136 WARN_ON(1);
1137 }
1138
1139 if (err || type == AUDIT_DEL_RULE) {
1140 if (entry->rule.exe)
1141 audit_remove_mark(entry->rule.exe);
1142 audit_free_rule(entry);
1143 }
1144
1145 return err;
1146}
1147
1148/**
1149 * audit_list_rules_send - list the audit rules
1150 * @request_skb: skb of request we are replying to (used to target the reply)
1151 * @seq: netlink audit message sequence (serial) number
1152 */
1153int audit_list_rules_send(struct sk_buff *request_skb, int seq)
1154{
1155 u32 portid = NETLINK_CB(request_skb).portid;
1156 struct net *net = sock_net(NETLINK_CB(request_skb).sk);
1157 struct task_struct *tsk;
1158 struct audit_netlink_list *dest;
1159 int err = 0;
1160
1161 /* We can't just spew out the rules here because we might fill
1162 * the available socket buffer space and deadlock waiting for
1163 * auditctl to read from it... which isn't ever going to
1164 * happen if we're actually running in the context of auditctl
1165 * trying to _send_ the stuff */
1166
1167 dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL);
1168 if (!dest)
1169 return -ENOMEM;
1170 dest->net = get_net(net);
1171 dest->portid = portid;
1172 skb_queue_head_init(&dest->q);
1173
1174 mutex_lock(&audit_filter_mutex);
1175 audit_list_rules(seq, &dest->q);
1176 mutex_unlock(&audit_filter_mutex);
1177
1178 tsk = kthread_run(audit_send_list, dest, "audit_send_list");
1179 if (IS_ERR(tsk)) {
1180 skb_queue_purge(&dest->q);
1181 kfree(dest);
1182 err = PTR_ERR(tsk);
1183 }
1184
1185 return err;
1186}
1187
1188int audit_comparator(u32 left, u32 op, u32 right)
1189{
1190 switch (op) {
1191 case Audit_equal:
1192 return (left == right);
1193 case Audit_not_equal:
1194 return (left != right);
1195 case Audit_lt:
1196 return (left < right);
1197 case Audit_le:
1198 return (left <= right);
1199 case Audit_gt:
1200 return (left > right);
1201 case Audit_ge:
1202 return (left >= right);
1203 case Audit_bitmask:
1204 return (left & right);
1205 case Audit_bittest:
1206 return ((left & right) == right);
1207 default:
1208 BUG();
1209 return 0;
1210 }
1211}
1212
1213int audit_uid_comparator(kuid_t left, u32 op, kuid_t right)
1214{
1215 switch (op) {
1216 case Audit_equal:
1217 return uid_eq(left, right);
1218 case Audit_not_equal:
1219 return !uid_eq(left, right);
1220 case Audit_lt:
1221 return uid_lt(left, right);
1222 case Audit_le:
1223 return uid_lte(left, right);
1224 case Audit_gt:
1225 return uid_gt(left, right);
1226 case Audit_ge:
1227 return uid_gte(left, right);
1228 case Audit_bitmask:
1229 case Audit_bittest:
1230 default:
1231 BUG();
1232 return 0;
1233 }
1234}
1235
1236int audit_gid_comparator(kgid_t left, u32 op, kgid_t right)
1237{
1238 switch (op) {
1239 case Audit_equal:
1240 return gid_eq(left, right);
1241 case Audit_not_equal:
1242 return !gid_eq(left, right);
1243 case Audit_lt:
1244 return gid_lt(left, right);
1245 case Audit_le:
1246 return gid_lte(left, right);
1247 case Audit_gt:
1248 return gid_gt(left, right);
1249 case Audit_ge:
1250 return gid_gte(left, right);
1251 case Audit_bitmask:
1252 case Audit_bittest:
1253 default:
1254 BUG();
1255 return 0;
1256 }
1257}
1258
1259/**
1260 * parent_len - find the length of the parent portion of a pathname
1261 * @path: pathname of which to determine length
1262 */
1263int parent_len(const char *path)
1264{
1265 int plen;
1266 const char *p;
1267
1268 plen = strlen(path);
1269
1270 if (plen == 0)
1271 return plen;
1272
1273 /* disregard trailing slashes */
1274 p = path + plen - 1;
1275 while ((*p == '/') && (p > path))
1276 p--;
1277
1278 /* walk backward until we find the next slash or hit beginning */
1279 while ((*p != '/') && (p > path))
1280 p--;
1281
1282 /* did we find a slash? Then increment to include it in path */
1283 if (*p == '/')
1284 p++;
1285
1286 return p - path;
1287}
1288
1289/**
1290 * audit_compare_dname_path - compare given dentry name with last component in
1291 * given path. Return of 0 indicates a match.
1292 * @dname: dentry name that we're comparing
1293 * @path: full pathname that we're comparing
1294 * @parentlen: length of the parent if known. Passing in AUDIT_NAME_FULL
1295 * here indicates that we must compute this value.
1296 */
1297int audit_compare_dname_path(const char *dname, const char *path, int parentlen)
1298{
1299 int dlen, pathlen;
1300 const char *p;
1301
1302 dlen = strlen(dname);
1303 pathlen = strlen(path);
1304 if (pathlen < dlen)
1305 return 1;
1306
1307 parentlen = parentlen == AUDIT_NAME_FULL ? parent_len(path) : parentlen;
1308 if (pathlen - parentlen != dlen)
1309 return 1;
1310
1311 p = path + parentlen;
1312
1313 return strncmp(p, dname, dlen);
1314}
1315
1316int audit_filter(int msgtype, unsigned int listtype)
1317{
1318 struct audit_entry *e;
1319 int ret = 1; /* Audit by default */
1320
1321 rcu_read_lock();
1322 if (list_empty(&audit_filter_list[listtype]))
1323 goto unlock_and_return;
1324 list_for_each_entry_rcu(e, &audit_filter_list[listtype], list) {
1325 int i, result = 0;
1326
1327 for (i = 0; i < e->rule.field_count; i++) {
1328 struct audit_field *f = &e->rule.fields[i];
1329 pid_t pid;
1330 u32 sid;
1331
1332 switch (f->type) {
1333 case AUDIT_PID:
1334 pid = task_pid_nr(current);
1335 result = audit_comparator(pid, f->op, f->val);
1336 break;
1337 case AUDIT_UID:
1338 result = audit_uid_comparator(current_uid(), f->op, f->uid);
1339 break;
1340 case AUDIT_GID:
1341 result = audit_gid_comparator(current_gid(), f->op, f->gid);
1342 break;
1343 case AUDIT_LOGINUID:
1344 result = audit_uid_comparator(audit_get_loginuid(current),
1345 f->op, f->uid);
1346 break;
1347 case AUDIT_LOGINUID_SET:
1348 result = audit_comparator(audit_loginuid_set(current),
1349 f->op, f->val);
1350 break;
1351 case AUDIT_MSGTYPE:
1352 result = audit_comparator(msgtype, f->op, f->val);
1353 break;
1354 case AUDIT_SUBJ_USER:
1355 case AUDIT_SUBJ_ROLE:
1356 case AUDIT_SUBJ_TYPE:
1357 case AUDIT_SUBJ_SEN:
1358 case AUDIT_SUBJ_CLR:
1359 if (f->lsm_rule) {
1360 security_task_getsecid(current, &sid);
1361 result = security_audit_rule_match(sid,
1362 f->type, f->op, f->lsm_rule, NULL);
1363 }
1364 break;
1365 default:
1366 goto unlock_and_return;
1367 }
1368 if (result < 0) /* error */
1369 goto unlock_and_return;
1370 if (!result)
1371 break;
1372 }
1373 if (result > 0) {
1374 if (e->rule.action == AUDIT_NEVER || listtype == AUDIT_FILTER_TYPE)
1375 ret = 0;
1376 break;
1377 }
1378 }
1379unlock_and_return:
1380 rcu_read_unlock();
1381 return ret;
1382}
1383
1384static int update_lsm_rule(struct audit_krule *r)
1385{
1386 struct audit_entry *entry = container_of(r, struct audit_entry, rule);
1387 struct audit_entry *nentry;
1388 int err = 0;
1389
1390 if (!security_audit_rule_known(r))
1391 return 0;
1392
1393 nentry = audit_dupe_rule(r);
1394 if (entry->rule.exe)
1395 audit_remove_mark(entry->rule.exe);
1396 if (IS_ERR(nentry)) {
1397 /* save the first error encountered for the
1398 * return value */
1399 err = PTR_ERR(nentry);
1400 audit_panic("error updating LSM filters");
1401 if (r->watch)
1402 list_del(&r->rlist);
1403 list_del_rcu(&entry->list);
1404 list_del(&r->list);
1405 } else {
1406 if (r->watch || r->tree)
1407 list_replace_init(&r->rlist, &nentry->rule.rlist);
1408 list_replace_rcu(&entry->list, &nentry->list);
1409 list_replace(&r->list, &nentry->rule.list);
1410 }
1411 call_rcu(&entry->rcu, audit_free_rule_rcu);
1412
1413 return err;
1414}
1415
1416/* This function will re-initialize the lsm_rule field of all applicable rules.
1417 * It will traverse the filter lists serarching for rules that contain LSM
1418 * specific filter fields. When such a rule is found, it is copied, the
1419 * LSM field is re-initialized, and the old rule is replaced with the
1420 * updated rule. */
1421int audit_update_lsm_rules(void)
1422{
1423 struct audit_krule *r, *n;
1424 int i, err = 0;
1425
1426 /* audit_filter_mutex synchronizes the writers */
1427 mutex_lock(&audit_filter_mutex);
1428
1429 for (i = 0; i < AUDIT_NR_FILTERS; i++) {
1430 list_for_each_entry_safe(r, n, &audit_rules_list[i], list) {
1431 int res = update_lsm_rule(r);
1432 if (!err)
1433 err = res;
1434 }
1435 }
1436 mutex_unlock(&audit_filter_mutex);
1437
1438 return err;
1439}
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}