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