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1// SPDX-License-Identifier: GPL-2.0-or-later
2/* auditfilter.c -- filtering of audit events
3 *
4 * Copyright 2003-2004 Red Hat, Inc.
5 * Copyright 2005 Hewlett-Packard Development Company, L.P.
6 * Copyright 2005 IBM Corporation
7 */
8
9#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
10
11#include <linux/kernel.h>
12#include <linux/audit.h>
13#include <linux/kthread.h>
14#include <linux/mutex.h>
15#include <linux/fs.h>
16#include <linux/namei.h>
17#include <linux/netlink.h>
18#include <linux/sched.h>
19#include <linux/slab.h>
20#include <linux/security.h>
21#include <net/net_namespace.h>
22#include <net/sock.h>
23#include "audit.h"
24
25/*
26 * Locking model:
27 *
28 * audit_filter_mutex:
29 * Synchronizes writes and blocking reads of audit's filterlist
30 * data. Rcu is used to traverse the filterlist and access
31 * contents of structs audit_entry, audit_watch and opaque
32 * LSM rules during filtering. If modified, these structures
33 * must be copied and replace their counterparts in the filterlist.
34 * An audit_parent struct is not accessed during filtering, so may
35 * be written directly provided audit_filter_mutex is held.
36 */
37
38/* Audit filter lists, defined in <linux/audit.h> */
39struct list_head audit_filter_list[AUDIT_NR_FILTERS] = {
40 LIST_HEAD_INIT(audit_filter_list[0]),
41 LIST_HEAD_INIT(audit_filter_list[1]),
42 LIST_HEAD_INIT(audit_filter_list[2]),
43 LIST_HEAD_INIT(audit_filter_list[3]),
44 LIST_HEAD_INIT(audit_filter_list[4]),
45 LIST_HEAD_INIT(audit_filter_list[5]),
46 LIST_HEAD_INIT(audit_filter_list[6]),
47 LIST_HEAD_INIT(audit_filter_list[7]),
48#if AUDIT_NR_FILTERS != 8
49#error Fix audit_filter_list initialiser
50#endif
51};
52static struct list_head audit_rules_list[AUDIT_NR_FILTERS] = {
53 LIST_HEAD_INIT(audit_rules_list[0]),
54 LIST_HEAD_INIT(audit_rules_list[1]),
55 LIST_HEAD_INIT(audit_rules_list[2]),
56 LIST_HEAD_INIT(audit_rules_list[3]),
57 LIST_HEAD_INIT(audit_rules_list[4]),
58 LIST_HEAD_INIT(audit_rules_list[5]),
59 LIST_HEAD_INIT(audit_rules_list[6]),
60 LIST_HEAD_INIT(audit_rules_list[7]),
61};
62
63DEFINE_MUTEX(audit_filter_mutex);
64
65static void audit_free_lsm_field(struct audit_field *f)
66{
67 switch (f->type) {
68 case AUDIT_SUBJ_USER:
69 case AUDIT_SUBJ_ROLE:
70 case AUDIT_SUBJ_TYPE:
71 case AUDIT_SUBJ_SEN:
72 case AUDIT_SUBJ_CLR:
73 case AUDIT_OBJ_USER:
74 case AUDIT_OBJ_ROLE:
75 case AUDIT_OBJ_TYPE:
76 case AUDIT_OBJ_LEV_LOW:
77 case AUDIT_OBJ_LEV_HIGH:
78 kfree(f->lsm_str);
79 security_audit_rule_free(f->lsm_rule);
80 }
81}
82
83static inline void audit_free_rule(struct audit_entry *e)
84{
85 int i;
86 struct audit_krule *erule = &e->rule;
87
88 /* some rules don't have associated watches */
89 if (erule->watch)
90 audit_put_watch(erule->watch);
91 if (erule->fields)
92 for (i = 0; i < erule->field_count; i++)
93 audit_free_lsm_field(&erule->fields[i]);
94 kfree(erule->fields);
95 kfree(erule->filterkey);
96 kfree(e);
97}
98
99void audit_free_rule_rcu(struct rcu_head *head)
100{
101 struct audit_entry *e = container_of(head, struct audit_entry, rcu);
102 audit_free_rule(e);
103}
104
105/* Initialize an audit filterlist entry. */
106static inline struct audit_entry *audit_init_entry(u32 field_count)
107{
108 struct audit_entry *entry;
109 struct audit_field *fields;
110
111 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
112 if (unlikely(!entry))
113 return NULL;
114
115 fields = kcalloc(field_count, sizeof(*fields), GFP_KERNEL);
116 if (unlikely(!fields)) {
117 kfree(entry);
118 return NULL;
119 }
120 entry->rule.fields = fields;
121
122 return entry;
123}
124
125/* Unpack a filter field's string representation from user-space
126 * buffer. */
127char *audit_unpack_string(void **bufp, size_t *remain, size_t len)
128{
129 char *str;
130
131 if (!*bufp || (len == 0) || (len > *remain))
132 return ERR_PTR(-EINVAL);
133
134 /* Of the currently implemented string fields, PATH_MAX
135 * defines the longest valid length.
136 */
137 if (len > PATH_MAX)
138 return ERR_PTR(-ENAMETOOLONG);
139
140 str = kmalloc(len + 1, GFP_KERNEL);
141 if (unlikely(!str))
142 return ERR_PTR(-ENOMEM);
143
144 memcpy(str, *bufp, len);
145 str[len] = 0;
146 *bufp += len;
147 *remain -= len;
148
149 return str;
150}
151
152/* Translate an inode field to kernel representation. */
153static inline int audit_to_inode(struct audit_krule *krule,
154 struct audit_field *f)
155{
156 if ((krule->listnr != AUDIT_FILTER_EXIT &&
157 krule->listnr != AUDIT_FILTER_URING_EXIT) ||
158 krule->inode_f || krule->watch || krule->tree ||
159 (f->op != Audit_equal && f->op != Audit_not_equal))
160 return -EINVAL;
161
162 krule->inode_f = f;
163 return 0;
164}
165
166static __u32 *classes[AUDIT_SYSCALL_CLASSES];
167
168int __init audit_register_class(int class, unsigned *list)
169{
170 __u32 *p = kcalloc(AUDIT_BITMASK_SIZE, sizeof(__u32), GFP_KERNEL);
171 if (!p)
172 return -ENOMEM;
173 while (*list != ~0U) {
174 unsigned n = *list++;
175 if (n >= AUDIT_BITMASK_SIZE * 32 - AUDIT_SYSCALL_CLASSES) {
176 kfree(p);
177 return -EINVAL;
178 }
179 p[AUDIT_WORD(n)] |= AUDIT_BIT(n);
180 }
181 if (class >= AUDIT_SYSCALL_CLASSES || classes[class]) {
182 kfree(p);
183 return -EINVAL;
184 }
185 classes[class] = p;
186 return 0;
187}
188
189int audit_match_class(int class, unsigned syscall)
190{
191 if (unlikely(syscall >= AUDIT_BITMASK_SIZE * 32))
192 return 0;
193 if (unlikely(class >= AUDIT_SYSCALL_CLASSES || !classes[class]))
194 return 0;
195 return classes[class][AUDIT_WORD(syscall)] & AUDIT_BIT(syscall);
196}
197
198#ifdef CONFIG_AUDITSYSCALL
199static inline int audit_match_class_bits(int class, u32 *mask)
200{
201 int i;
202
203 if (classes[class]) {
204 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
205 if (mask[i] & classes[class][i])
206 return 0;
207 }
208 return 1;
209}
210
211static int audit_match_signal(struct audit_entry *entry)
212{
213 struct audit_field *arch = entry->rule.arch_f;
214
215 if (!arch) {
216 /* When arch is unspecified, we must check both masks on biarch
217 * as syscall number alone is ambiguous. */
218 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
219 entry->rule.mask) &&
220 audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
221 entry->rule.mask));
222 }
223
224 switch(audit_classify_arch(arch->val)) {
225 case 0: /* native */
226 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
227 entry->rule.mask));
228 case 1: /* 32bit on biarch */
229 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
230 entry->rule.mask));
231 default:
232 return 1;
233 }
234}
235#endif
236
237/* Common user-space to kernel rule translation. */
238static inline struct audit_entry *audit_to_entry_common(struct audit_rule_data *rule)
239{
240 unsigned listnr;
241 struct audit_entry *entry;
242 int i, err;
243
244 err = -EINVAL;
245 listnr = rule->flags & ~AUDIT_FILTER_PREPEND;
246 switch(listnr) {
247 default:
248 goto exit_err;
249#ifdef CONFIG_AUDITSYSCALL
250 case AUDIT_FILTER_ENTRY:
251 pr_err("AUDIT_FILTER_ENTRY is deprecated\n");
252 goto exit_err;
253 case AUDIT_FILTER_EXIT:
254 case AUDIT_FILTER_URING_EXIT:
255 case AUDIT_FILTER_TASK:
256#endif
257 case AUDIT_FILTER_USER:
258 case AUDIT_FILTER_EXCLUDE:
259 case AUDIT_FILTER_FS:
260 ;
261 }
262 if (unlikely(rule->action == AUDIT_POSSIBLE)) {
263 pr_err("AUDIT_POSSIBLE is deprecated\n");
264 goto exit_err;
265 }
266 if (rule->action != AUDIT_NEVER && rule->action != AUDIT_ALWAYS)
267 goto exit_err;
268 if (rule->field_count > AUDIT_MAX_FIELDS)
269 goto exit_err;
270
271 err = -ENOMEM;
272 entry = audit_init_entry(rule->field_count);
273 if (!entry)
274 goto exit_err;
275
276 entry->rule.flags = rule->flags & AUDIT_FILTER_PREPEND;
277 entry->rule.listnr = listnr;
278 entry->rule.action = rule->action;
279 entry->rule.field_count = rule->field_count;
280
281 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
282 entry->rule.mask[i] = rule->mask[i];
283
284 for (i = 0; i < AUDIT_SYSCALL_CLASSES; i++) {
285 int bit = AUDIT_BITMASK_SIZE * 32 - i - 1;
286 __u32 *p = &entry->rule.mask[AUDIT_WORD(bit)];
287 __u32 *class;
288
289 if (!(*p & AUDIT_BIT(bit)))
290 continue;
291 *p &= ~AUDIT_BIT(bit);
292 class = classes[i];
293 if (class) {
294 int j;
295 for (j = 0; j < AUDIT_BITMASK_SIZE; j++)
296 entry->rule.mask[j] |= class[j];
297 }
298 }
299
300 return entry;
301
302exit_err:
303 return ERR_PTR(err);
304}
305
306static u32 audit_ops[] =
307{
308 [Audit_equal] = AUDIT_EQUAL,
309 [Audit_not_equal] = AUDIT_NOT_EQUAL,
310 [Audit_bitmask] = AUDIT_BIT_MASK,
311 [Audit_bittest] = AUDIT_BIT_TEST,
312 [Audit_lt] = AUDIT_LESS_THAN,
313 [Audit_gt] = AUDIT_GREATER_THAN,
314 [Audit_le] = AUDIT_LESS_THAN_OR_EQUAL,
315 [Audit_ge] = AUDIT_GREATER_THAN_OR_EQUAL,
316};
317
318static u32 audit_to_op(u32 op)
319{
320 u32 n;
321 for (n = Audit_equal; n < Audit_bad && audit_ops[n] != op; n++)
322 ;
323 return n;
324}
325
326/* check if an audit field is valid */
327static int audit_field_valid(struct audit_entry *entry, struct audit_field *f)
328{
329 switch (f->type) {
330 case AUDIT_MSGTYPE:
331 if (entry->rule.listnr != AUDIT_FILTER_EXCLUDE &&
332 entry->rule.listnr != AUDIT_FILTER_USER)
333 return -EINVAL;
334 break;
335 case AUDIT_FSTYPE:
336 if (entry->rule.listnr != AUDIT_FILTER_FS)
337 return -EINVAL;
338 break;
339 case AUDIT_PERM:
340 if (entry->rule.listnr == AUDIT_FILTER_URING_EXIT)
341 return -EINVAL;
342 break;
343 }
344
345 switch (entry->rule.listnr) {
346 case AUDIT_FILTER_FS:
347 switch(f->type) {
348 case AUDIT_FSTYPE:
349 case AUDIT_FILTERKEY:
350 break;
351 default:
352 return -EINVAL;
353 }
354 }
355
356 /* Check for valid field type and op */
357 switch (f->type) {
358 case AUDIT_ARG0:
359 case AUDIT_ARG1:
360 case AUDIT_ARG2:
361 case AUDIT_ARG3:
362 case AUDIT_PERS: /* <uapi/linux/personality.h> */
363 case AUDIT_DEVMINOR:
364 /* all ops are valid */
365 break;
366 case AUDIT_UID:
367 case AUDIT_EUID:
368 case AUDIT_SUID:
369 case AUDIT_FSUID:
370 case AUDIT_LOGINUID:
371 case AUDIT_OBJ_UID:
372 case AUDIT_GID:
373 case AUDIT_EGID:
374 case AUDIT_SGID:
375 case AUDIT_FSGID:
376 case AUDIT_OBJ_GID:
377 case AUDIT_PID:
378 case AUDIT_MSGTYPE:
379 case AUDIT_PPID:
380 case AUDIT_DEVMAJOR:
381 case AUDIT_EXIT:
382 case AUDIT_SUCCESS:
383 case AUDIT_INODE:
384 case AUDIT_SESSIONID:
385 case AUDIT_SUBJ_SEN:
386 case AUDIT_SUBJ_CLR:
387 case AUDIT_OBJ_LEV_LOW:
388 case AUDIT_OBJ_LEV_HIGH:
389 case AUDIT_SADDR_FAM:
390 /* bit ops are only useful on syscall args */
391 if (f->op == Audit_bitmask || f->op == Audit_bittest)
392 return -EINVAL;
393 break;
394 case AUDIT_SUBJ_USER:
395 case AUDIT_SUBJ_ROLE:
396 case AUDIT_SUBJ_TYPE:
397 case AUDIT_OBJ_USER:
398 case AUDIT_OBJ_ROLE:
399 case AUDIT_OBJ_TYPE:
400 case AUDIT_WATCH:
401 case AUDIT_DIR:
402 case AUDIT_FILTERKEY:
403 case AUDIT_LOGINUID_SET:
404 case AUDIT_ARCH:
405 case AUDIT_FSTYPE:
406 case AUDIT_PERM:
407 case AUDIT_FILETYPE:
408 case AUDIT_FIELD_COMPARE:
409 case AUDIT_EXE:
410 /* only equal and not equal valid ops */
411 if (f->op != Audit_not_equal && f->op != Audit_equal)
412 return -EINVAL;
413 break;
414 default:
415 /* field not recognized */
416 return -EINVAL;
417 }
418
419 /* Check for select valid field values */
420 switch (f->type) {
421 case AUDIT_LOGINUID_SET:
422 if ((f->val != 0) && (f->val != 1))
423 return -EINVAL;
424 break;
425 case AUDIT_PERM:
426 if (f->val & ~15)
427 return -EINVAL;
428 break;
429 case AUDIT_FILETYPE:
430 if (f->val & ~S_IFMT)
431 return -EINVAL;
432 break;
433 case AUDIT_FIELD_COMPARE:
434 if (f->val > AUDIT_MAX_FIELD_COMPARE)
435 return -EINVAL;
436 break;
437 case AUDIT_SADDR_FAM:
438 if (f->val >= AF_MAX)
439 return -EINVAL;
440 break;
441 default:
442 break;
443 }
444
445 return 0;
446}
447
448/* Translate struct audit_rule_data to kernel's rule representation. */
449static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
450 size_t datasz)
451{
452 int err = 0;
453 struct audit_entry *entry;
454 void *bufp;
455 size_t remain = datasz - sizeof(struct audit_rule_data);
456 int i;
457 char *str;
458 struct audit_fsnotify_mark *audit_mark;
459
460 entry = audit_to_entry_common(data);
461 if (IS_ERR(entry))
462 goto exit_nofree;
463
464 bufp = data->buf;
465 for (i = 0; i < data->field_count; i++) {
466 struct audit_field *f = &entry->rule.fields[i];
467 u32 f_val;
468
469 err = -EINVAL;
470
471 f->op = audit_to_op(data->fieldflags[i]);
472 if (f->op == Audit_bad)
473 goto exit_free;
474
475 f->type = data->fields[i];
476 f_val = data->values[i];
477
478 /* Support legacy tests for a valid loginuid */
479 if ((f->type == AUDIT_LOGINUID) && (f_val == AUDIT_UID_UNSET)) {
480 f->type = AUDIT_LOGINUID_SET;
481 f_val = 0;
482 entry->rule.pflags |= AUDIT_LOGINUID_LEGACY;
483 }
484
485 err = audit_field_valid(entry, f);
486 if (err)
487 goto exit_free;
488
489 err = -EINVAL;
490 switch (f->type) {
491 case AUDIT_LOGINUID:
492 case AUDIT_UID:
493 case AUDIT_EUID:
494 case AUDIT_SUID:
495 case AUDIT_FSUID:
496 case AUDIT_OBJ_UID:
497 f->uid = make_kuid(current_user_ns(), f_val);
498 if (!uid_valid(f->uid))
499 goto exit_free;
500 break;
501 case AUDIT_GID:
502 case AUDIT_EGID:
503 case AUDIT_SGID:
504 case AUDIT_FSGID:
505 case AUDIT_OBJ_GID:
506 f->gid = make_kgid(current_user_ns(), f_val);
507 if (!gid_valid(f->gid))
508 goto exit_free;
509 break;
510 case AUDIT_ARCH:
511 f->val = f_val;
512 entry->rule.arch_f = f;
513 break;
514 case AUDIT_SUBJ_USER:
515 case AUDIT_SUBJ_ROLE:
516 case AUDIT_SUBJ_TYPE:
517 case AUDIT_SUBJ_SEN:
518 case AUDIT_SUBJ_CLR:
519 case AUDIT_OBJ_USER:
520 case AUDIT_OBJ_ROLE:
521 case AUDIT_OBJ_TYPE:
522 case AUDIT_OBJ_LEV_LOW:
523 case AUDIT_OBJ_LEV_HIGH:
524 str = audit_unpack_string(&bufp, &remain, f_val);
525 if (IS_ERR(str)) {
526 err = PTR_ERR(str);
527 goto exit_free;
528 }
529 entry->rule.buflen += f_val;
530 f->lsm_str = str;
531 err = security_audit_rule_init(f->type, f->op, str,
532 (void **)&f->lsm_rule);
533 /* Keep currently invalid fields around in case they
534 * become valid after a policy reload. */
535 if (err == -EINVAL) {
536 pr_warn("audit rule for LSM \'%s\' is invalid\n",
537 str);
538 err = 0;
539 } else if (err)
540 goto exit_free;
541 break;
542 case AUDIT_WATCH:
543 str = audit_unpack_string(&bufp, &remain, f_val);
544 if (IS_ERR(str)) {
545 err = PTR_ERR(str);
546 goto exit_free;
547 }
548 err = audit_to_watch(&entry->rule, str, f_val, f->op);
549 if (err) {
550 kfree(str);
551 goto exit_free;
552 }
553 entry->rule.buflen += f_val;
554 break;
555 case AUDIT_DIR:
556 str = audit_unpack_string(&bufp, &remain, f_val);
557 if (IS_ERR(str)) {
558 err = PTR_ERR(str);
559 goto exit_free;
560 }
561 err = audit_make_tree(&entry->rule, str, f->op);
562 kfree(str);
563 if (err)
564 goto exit_free;
565 entry->rule.buflen += f_val;
566 break;
567 case AUDIT_INODE:
568 f->val = f_val;
569 err = audit_to_inode(&entry->rule, f);
570 if (err)
571 goto exit_free;
572 break;
573 case AUDIT_FILTERKEY:
574 if (entry->rule.filterkey || f_val > AUDIT_MAX_KEY_LEN)
575 goto exit_free;
576 str = audit_unpack_string(&bufp, &remain, f_val);
577 if (IS_ERR(str)) {
578 err = PTR_ERR(str);
579 goto exit_free;
580 }
581 entry->rule.buflen += f_val;
582 entry->rule.filterkey = str;
583 break;
584 case AUDIT_EXE:
585 if (entry->rule.exe || f_val > PATH_MAX)
586 goto exit_free;
587 str = audit_unpack_string(&bufp, &remain, f_val);
588 if (IS_ERR(str)) {
589 err = PTR_ERR(str);
590 goto exit_free;
591 }
592 audit_mark = audit_alloc_mark(&entry->rule, str, f_val);
593 if (IS_ERR(audit_mark)) {
594 kfree(str);
595 err = PTR_ERR(audit_mark);
596 goto exit_free;
597 }
598 entry->rule.buflen += f_val;
599 entry->rule.exe = audit_mark;
600 break;
601 default:
602 f->val = f_val;
603 break;
604 }
605 }
606
607 if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal)
608 entry->rule.inode_f = NULL;
609
610exit_nofree:
611 return entry;
612
613exit_free:
614 if (entry->rule.tree)
615 audit_put_tree(entry->rule.tree); /* that's the temporary one */
616 if (entry->rule.exe)
617 audit_remove_mark(entry->rule.exe); /* that's the template one */
618 audit_free_rule(entry);
619 return ERR_PTR(err);
620}
621
622/* Pack a filter field's string representation into data block. */
623static inline size_t audit_pack_string(void **bufp, const char *str)
624{
625 size_t len = strlen(str);
626
627 memcpy(*bufp, str, len);
628 *bufp += len;
629
630 return len;
631}
632
633/* Translate kernel rule representation to struct audit_rule_data. */
634static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule)
635{
636 struct audit_rule_data *data;
637 void *bufp;
638 int i;
639
640 data = kmalloc(struct_size(data, buf, krule->buflen), GFP_KERNEL);
641 if (unlikely(!data))
642 return NULL;
643 memset(data, 0, sizeof(*data));
644
645 data->flags = krule->flags | krule->listnr;
646 data->action = krule->action;
647 data->field_count = krule->field_count;
648 bufp = data->buf;
649 for (i = 0; i < data->field_count; i++) {
650 struct audit_field *f = &krule->fields[i];
651
652 data->fields[i] = f->type;
653 data->fieldflags[i] = audit_ops[f->op];
654 switch(f->type) {
655 case AUDIT_SUBJ_USER:
656 case AUDIT_SUBJ_ROLE:
657 case AUDIT_SUBJ_TYPE:
658 case AUDIT_SUBJ_SEN:
659 case AUDIT_SUBJ_CLR:
660 case AUDIT_OBJ_USER:
661 case AUDIT_OBJ_ROLE:
662 case AUDIT_OBJ_TYPE:
663 case AUDIT_OBJ_LEV_LOW:
664 case AUDIT_OBJ_LEV_HIGH:
665 data->buflen += data->values[i] =
666 audit_pack_string(&bufp, f->lsm_str);
667 break;
668 case AUDIT_WATCH:
669 data->buflen += data->values[i] =
670 audit_pack_string(&bufp,
671 audit_watch_path(krule->watch));
672 break;
673 case AUDIT_DIR:
674 data->buflen += data->values[i] =
675 audit_pack_string(&bufp,
676 audit_tree_path(krule->tree));
677 break;
678 case AUDIT_FILTERKEY:
679 data->buflen += data->values[i] =
680 audit_pack_string(&bufp, krule->filterkey);
681 break;
682 case AUDIT_EXE:
683 data->buflen += data->values[i] =
684 audit_pack_string(&bufp, audit_mark_path(krule->exe));
685 break;
686 case AUDIT_LOGINUID_SET:
687 if (krule->pflags & AUDIT_LOGINUID_LEGACY && !f->val) {
688 data->fields[i] = AUDIT_LOGINUID;
689 data->values[i] = AUDIT_UID_UNSET;
690 break;
691 }
692 fallthrough; /* if set */
693 default:
694 data->values[i] = f->val;
695 }
696 }
697 for (i = 0; i < AUDIT_BITMASK_SIZE; i++) data->mask[i] = krule->mask[i];
698
699 return data;
700}
701
702/* Compare two rules in kernel format. Considered success if rules
703 * don't match. */
704static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
705{
706 int i;
707
708 if (a->flags != b->flags ||
709 a->pflags != b->pflags ||
710 a->listnr != b->listnr ||
711 a->action != b->action ||
712 a->field_count != b->field_count)
713 return 1;
714
715 for (i = 0; i < a->field_count; i++) {
716 if (a->fields[i].type != b->fields[i].type ||
717 a->fields[i].op != b->fields[i].op)
718 return 1;
719
720 switch(a->fields[i].type) {
721 case AUDIT_SUBJ_USER:
722 case AUDIT_SUBJ_ROLE:
723 case AUDIT_SUBJ_TYPE:
724 case AUDIT_SUBJ_SEN:
725 case AUDIT_SUBJ_CLR:
726 case AUDIT_OBJ_USER:
727 case AUDIT_OBJ_ROLE:
728 case AUDIT_OBJ_TYPE:
729 case AUDIT_OBJ_LEV_LOW:
730 case AUDIT_OBJ_LEV_HIGH:
731 if (strcmp(a->fields[i].lsm_str, b->fields[i].lsm_str))
732 return 1;
733 break;
734 case AUDIT_WATCH:
735 if (strcmp(audit_watch_path(a->watch),
736 audit_watch_path(b->watch)))
737 return 1;
738 break;
739 case AUDIT_DIR:
740 if (strcmp(audit_tree_path(a->tree),
741 audit_tree_path(b->tree)))
742 return 1;
743 break;
744 case AUDIT_FILTERKEY:
745 /* both filterkeys exist based on above type compare */
746 if (strcmp(a->filterkey, b->filterkey))
747 return 1;
748 break;
749 case AUDIT_EXE:
750 /* both paths exist based on above type compare */
751 if (strcmp(audit_mark_path(a->exe),
752 audit_mark_path(b->exe)))
753 return 1;
754 break;
755 case AUDIT_UID:
756 case AUDIT_EUID:
757 case AUDIT_SUID:
758 case AUDIT_FSUID:
759 case AUDIT_LOGINUID:
760 case AUDIT_OBJ_UID:
761 if (!uid_eq(a->fields[i].uid, b->fields[i].uid))
762 return 1;
763 break;
764 case AUDIT_GID:
765 case AUDIT_EGID:
766 case AUDIT_SGID:
767 case AUDIT_FSGID:
768 case AUDIT_OBJ_GID:
769 if (!gid_eq(a->fields[i].gid, b->fields[i].gid))
770 return 1;
771 break;
772 default:
773 if (a->fields[i].val != b->fields[i].val)
774 return 1;
775 }
776 }
777
778 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
779 if (a->mask[i] != b->mask[i])
780 return 1;
781
782 return 0;
783}
784
785/* Duplicate LSM field information. The lsm_rule is opaque, so must be
786 * re-initialized. */
787static inline int audit_dupe_lsm_field(struct audit_field *df,
788 struct audit_field *sf)
789{
790 int ret = 0;
791 char *lsm_str;
792
793 /* our own copy of lsm_str */
794 lsm_str = kstrdup(sf->lsm_str, GFP_KERNEL);
795 if (unlikely(!lsm_str))
796 return -ENOMEM;
797 df->lsm_str = lsm_str;
798
799 /* our own (refreshed) copy of lsm_rule */
800 ret = security_audit_rule_init(df->type, df->op, df->lsm_str,
801 (void **)&df->lsm_rule);
802 /* Keep currently invalid fields around in case they
803 * become valid after a policy reload. */
804 if (ret == -EINVAL) {
805 pr_warn("audit rule for LSM \'%s\' is invalid\n",
806 df->lsm_str);
807 ret = 0;
808 }
809
810 return ret;
811}
812
813/* Duplicate an audit rule. This will be a deep copy with the exception
814 * of the watch - that pointer is carried over. The LSM specific fields
815 * will be updated in the copy. The point is to be able to replace the old
816 * rule with the new rule in the filterlist, then free the old rule.
817 * The rlist element is undefined; list manipulations are handled apart from
818 * the initial copy. */
819struct audit_entry *audit_dupe_rule(struct audit_krule *old)
820{
821 u32 fcount = old->field_count;
822 struct audit_entry *entry;
823 struct audit_krule *new;
824 char *fk;
825 int i, err = 0;
826
827 entry = audit_init_entry(fcount);
828 if (unlikely(!entry))
829 return ERR_PTR(-ENOMEM);
830
831 new = &entry->rule;
832 new->flags = old->flags;
833 new->pflags = old->pflags;
834 new->listnr = old->listnr;
835 new->action = old->action;
836 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
837 new->mask[i] = old->mask[i];
838 new->prio = old->prio;
839 new->buflen = old->buflen;
840 new->inode_f = old->inode_f;
841 new->field_count = old->field_count;
842
843 /*
844 * note that we are OK with not refcounting here; audit_match_tree()
845 * never dereferences tree and we can't get false positives there
846 * since we'd have to have rule gone from the list *and* removed
847 * before the chunks found by lookup had been allocated, i.e. before
848 * the beginning of list scan.
849 */
850 new->tree = old->tree;
851 memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount);
852
853 /* deep copy this information, updating the lsm_rule fields, because
854 * the originals will all be freed when the old rule is freed. */
855 for (i = 0; i < fcount; i++) {
856 switch (new->fields[i].type) {
857 case AUDIT_SUBJ_USER:
858 case AUDIT_SUBJ_ROLE:
859 case AUDIT_SUBJ_TYPE:
860 case AUDIT_SUBJ_SEN:
861 case AUDIT_SUBJ_CLR:
862 case AUDIT_OBJ_USER:
863 case AUDIT_OBJ_ROLE:
864 case AUDIT_OBJ_TYPE:
865 case AUDIT_OBJ_LEV_LOW:
866 case AUDIT_OBJ_LEV_HIGH:
867 err = audit_dupe_lsm_field(&new->fields[i],
868 &old->fields[i]);
869 break;
870 case AUDIT_FILTERKEY:
871 fk = kstrdup(old->filterkey, GFP_KERNEL);
872 if (unlikely(!fk))
873 err = -ENOMEM;
874 else
875 new->filterkey = fk;
876 break;
877 case AUDIT_EXE:
878 err = audit_dupe_exe(new, old);
879 break;
880 }
881 if (err) {
882 if (new->exe)
883 audit_remove_mark(new->exe);
884 audit_free_rule(entry);
885 return ERR_PTR(err);
886 }
887 }
888
889 if (old->watch) {
890 audit_get_watch(old->watch);
891 new->watch = old->watch;
892 }
893
894 return entry;
895}
896
897/* Find an existing audit rule.
898 * Caller must hold audit_filter_mutex to prevent stale rule data. */
899static struct audit_entry *audit_find_rule(struct audit_entry *entry,
900 struct list_head **p)
901{
902 struct audit_entry *e, *found = NULL;
903 struct list_head *list;
904 int h;
905
906 if (entry->rule.inode_f) {
907 h = audit_hash_ino(entry->rule.inode_f->val);
908 *p = list = &audit_inode_hash[h];
909 } else if (entry->rule.watch) {
910 /* we don't know the inode number, so must walk entire hash */
911 for (h = 0; h < AUDIT_INODE_BUCKETS; h++) {
912 list = &audit_inode_hash[h];
913 list_for_each_entry(e, list, list)
914 if (!audit_compare_rule(&entry->rule, &e->rule)) {
915 found = e;
916 goto out;
917 }
918 }
919 goto out;
920 } else {
921 *p = list = &audit_filter_list[entry->rule.listnr];
922 }
923
924 list_for_each_entry(e, list, list)
925 if (!audit_compare_rule(&entry->rule, &e->rule)) {
926 found = e;
927 goto out;
928 }
929
930out:
931 return found;
932}
933
934static u64 prio_low = ~0ULL/2;
935static u64 prio_high = ~0ULL/2 - 1;
936
937/* Add rule to given filterlist if not a duplicate. */
938static inline int audit_add_rule(struct audit_entry *entry)
939{
940 struct audit_entry *e;
941 struct audit_watch *watch = entry->rule.watch;
942 struct audit_tree *tree = entry->rule.tree;
943 struct list_head *list;
944 int err = 0;
945#ifdef CONFIG_AUDITSYSCALL
946 int dont_count = 0;
947
948 /* If any of these, don't count towards total */
949 switch(entry->rule.listnr) {
950 case AUDIT_FILTER_USER:
951 case AUDIT_FILTER_EXCLUDE:
952 case AUDIT_FILTER_FS:
953 dont_count = 1;
954 }
955#endif
956
957 mutex_lock(&audit_filter_mutex);
958 e = audit_find_rule(entry, &list);
959 if (e) {
960 mutex_unlock(&audit_filter_mutex);
961 err = -EEXIST;
962 /* normally audit_add_tree_rule() will free it on failure */
963 if (tree)
964 audit_put_tree(tree);
965 return err;
966 }
967
968 if (watch) {
969 /* audit_filter_mutex is dropped and re-taken during this call */
970 err = audit_add_watch(&entry->rule, &list);
971 if (err) {
972 mutex_unlock(&audit_filter_mutex);
973 /*
974 * normally audit_add_tree_rule() will free it
975 * on failure
976 */
977 if (tree)
978 audit_put_tree(tree);
979 return err;
980 }
981 }
982 if (tree) {
983 err = audit_add_tree_rule(&entry->rule);
984 if (err) {
985 mutex_unlock(&audit_filter_mutex);
986 return err;
987 }
988 }
989
990 entry->rule.prio = ~0ULL;
991 if (entry->rule.listnr == AUDIT_FILTER_EXIT ||
992 entry->rule.listnr == AUDIT_FILTER_URING_EXIT) {
993 if (entry->rule.flags & AUDIT_FILTER_PREPEND)
994 entry->rule.prio = ++prio_high;
995 else
996 entry->rule.prio = --prio_low;
997 }
998
999 if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
1000 list_add(&entry->rule.list,
1001 &audit_rules_list[entry->rule.listnr]);
1002 list_add_rcu(&entry->list, list);
1003 entry->rule.flags &= ~AUDIT_FILTER_PREPEND;
1004 } else {
1005 list_add_tail(&entry->rule.list,
1006 &audit_rules_list[entry->rule.listnr]);
1007 list_add_tail_rcu(&entry->list, list);
1008 }
1009#ifdef CONFIG_AUDITSYSCALL
1010 if (!dont_count)
1011 audit_n_rules++;
1012
1013 if (!audit_match_signal(entry))
1014 audit_signals++;
1015#endif
1016 mutex_unlock(&audit_filter_mutex);
1017
1018 return err;
1019}
1020
1021/* Remove an existing rule from filterlist. */
1022int audit_del_rule(struct audit_entry *entry)
1023{
1024 struct audit_entry *e;
1025 struct audit_tree *tree = entry->rule.tree;
1026 struct list_head *list;
1027 int ret = 0;
1028#ifdef CONFIG_AUDITSYSCALL
1029 int dont_count = 0;
1030
1031 /* If any of these, don't count towards total */
1032 switch(entry->rule.listnr) {
1033 case AUDIT_FILTER_USER:
1034 case AUDIT_FILTER_EXCLUDE:
1035 case AUDIT_FILTER_FS:
1036 dont_count = 1;
1037 }
1038#endif
1039
1040 mutex_lock(&audit_filter_mutex);
1041 e = audit_find_rule(entry, &list);
1042 if (!e) {
1043 ret = -ENOENT;
1044 goto out;
1045 }
1046
1047 if (e->rule.watch)
1048 audit_remove_watch_rule(&e->rule);
1049
1050 if (e->rule.tree)
1051 audit_remove_tree_rule(&e->rule);
1052
1053 if (e->rule.exe)
1054 audit_remove_mark_rule(&e->rule);
1055
1056#ifdef CONFIG_AUDITSYSCALL
1057 if (!dont_count)
1058 audit_n_rules--;
1059
1060 if (!audit_match_signal(entry))
1061 audit_signals--;
1062#endif
1063
1064 list_del_rcu(&e->list);
1065 list_del(&e->rule.list);
1066 call_rcu(&e->rcu, audit_free_rule_rcu);
1067
1068out:
1069 mutex_unlock(&audit_filter_mutex);
1070
1071 if (tree)
1072 audit_put_tree(tree); /* that's the temporary one */
1073
1074 return ret;
1075}
1076
1077/* List rules using struct audit_rule_data. */
1078static void audit_list_rules(int seq, struct sk_buff_head *q)
1079{
1080 struct sk_buff *skb;
1081 struct audit_krule *r;
1082 int i;
1083
1084 /* This is a blocking read, so use audit_filter_mutex instead of rcu
1085 * iterator to sync with list writers. */
1086 for (i=0; i<AUDIT_NR_FILTERS; i++) {
1087 list_for_each_entry(r, &audit_rules_list[i], list) {
1088 struct audit_rule_data *data;
1089
1090 data = audit_krule_to_data(r);
1091 if (unlikely(!data))
1092 break;
1093 skb = audit_make_reply(seq, AUDIT_LIST_RULES, 0, 1,
1094 data,
1095 struct_size(data, buf, data->buflen));
1096 if (skb)
1097 skb_queue_tail(q, skb);
1098 kfree(data);
1099 }
1100 }
1101 skb = audit_make_reply(seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);
1102 if (skb)
1103 skb_queue_tail(q, skb);
1104}
1105
1106/* Log rule additions and removals */
1107static void audit_log_rule_change(char *action, struct audit_krule *rule, int res)
1108{
1109 struct audit_buffer *ab;
1110
1111 if (!audit_enabled)
1112 return;
1113
1114 ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_CONFIG_CHANGE);
1115 if (!ab)
1116 return;
1117 audit_log_session_info(ab);
1118 audit_log_task_context(ab);
1119 audit_log_format(ab, " op=%s", action);
1120 audit_log_key(ab, rule->filterkey);
1121 audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
1122 audit_log_end(ab);
1123}
1124
1125/**
1126 * audit_rule_change - apply all rules to the specified message type
1127 * @type: audit message type
1128 * @seq: netlink audit message sequence (serial) number
1129 * @data: payload data
1130 * @datasz: size of payload data
1131 */
1132int audit_rule_change(int type, int seq, void *data, size_t datasz)
1133{
1134 int err = 0;
1135 struct audit_entry *entry;
1136
1137 switch (type) {
1138 case AUDIT_ADD_RULE:
1139 entry = audit_data_to_entry(data, datasz);
1140 if (IS_ERR(entry))
1141 return PTR_ERR(entry);
1142 err = audit_add_rule(entry);
1143 audit_log_rule_change("add_rule", &entry->rule, !err);
1144 break;
1145 case AUDIT_DEL_RULE:
1146 entry = audit_data_to_entry(data, datasz);
1147 if (IS_ERR(entry))
1148 return PTR_ERR(entry);
1149 err = audit_del_rule(entry);
1150 audit_log_rule_change("remove_rule", &entry->rule, !err);
1151 break;
1152 default:
1153 WARN_ON(1);
1154 return -EINVAL;
1155 }
1156
1157 if (err || type == AUDIT_DEL_RULE) {
1158 if (entry->rule.exe)
1159 audit_remove_mark(entry->rule.exe);
1160 audit_free_rule(entry);
1161 }
1162
1163 return err;
1164}
1165
1166/**
1167 * audit_list_rules_send - list the audit rules
1168 * @request_skb: skb of request we are replying to (used to target the reply)
1169 * @seq: netlink audit message sequence (serial) number
1170 */
1171int audit_list_rules_send(struct sk_buff *request_skb, int seq)
1172{
1173 struct task_struct *tsk;
1174 struct audit_netlink_list *dest;
1175
1176 /* We can't just spew out the rules here because we might fill
1177 * the available socket buffer space and deadlock waiting for
1178 * auditctl to read from it... which isn't ever going to
1179 * happen if we're actually running in the context of auditctl
1180 * trying to _send_ the stuff */
1181
1182 dest = kmalloc(sizeof(*dest), GFP_KERNEL);
1183 if (!dest)
1184 return -ENOMEM;
1185 dest->net = get_net(sock_net(NETLINK_CB(request_skb).sk));
1186 dest->portid = NETLINK_CB(request_skb).portid;
1187 skb_queue_head_init(&dest->q);
1188
1189 mutex_lock(&audit_filter_mutex);
1190 audit_list_rules(seq, &dest->q);
1191 mutex_unlock(&audit_filter_mutex);
1192
1193 tsk = kthread_run(audit_send_list_thread, dest, "audit_send_list");
1194 if (IS_ERR(tsk)) {
1195 skb_queue_purge(&dest->q);
1196 put_net(dest->net);
1197 kfree(dest);
1198 return PTR_ERR(tsk);
1199 }
1200
1201 return 0;
1202}
1203
1204int audit_comparator(u32 left, u32 op, u32 right)
1205{
1206 switch (op) {
1207 case Audit_equal:
1208 return (left == right);
1209 case Audit_not_equal:
1210 return (left != right);
1211 case Audit_lt:
1212 return (left < right);
1213 case Audit_le:
1214 return (left <= right);
1215 case Audit_gt:
1216 return (left > right);
1217 case Audit_ge:
1218 return (left >= right);
1219 case Audit_bitmask:
1220 return (left & right);
1221 case Audit_bittest:
1222 return ((left & right) == right);
1223 default:
1224 return 0;
1225 }
1226}
1227
1228int audit_uid_comparator(kuid_t left, u32 op, kuid_t right)
1229{
1230 switch (op) {
1231 case Audit_equal:
1232 return uid_eq(left, right);
1233 case Audit_not_equal:
1234 return !uid_eq(left, right);
1235 case Audit_lt:
1236 return uid_lt(left, right);
1237 case Audit_le:
1238 return uid_lte(left, right);
1239 case Audit_gt:
1240 return uid_gt(left, right);
1241 case Audit_ge:
1242 return uid_gte(left, right);
1243 case Audit_bitmask:
1244 case Audit_bittest:
1245 default:
1246 return 0;
1247 }
1248}
1249
1250int audit_gid_comparator(kgid_t left, u32 op, kgid_t right)
1251{
1252 switch (op) {
1253 case Audit_equal:
1254 return gid_eq(left, right);
1255 case Audit_not_equal:
1256 return !gid_eq(left, right);
1257 case Audit_lt:
1258 return gid_lt(left, right);
1259 case Audit_le:
1260 return gid_lte(left, right);
1261 case Audit_gt:
1262 return gid_gt(left, right);
1263 case Audit_ge:
1264 return gid_gte(left, right);
1265 case Audit_bitmask:
1266 case Audit_bittest:
1267 default:
1268 return 0;
1269 }
1270}
1271
1272/**
1273 * parent_len - find the length of the parent portion of a pathname
1274 * @path: pathname of which to determine length
1275 */
1276int parent_len(const char *path)
1277{
1278 int plen;
1279 const char *p;
1280
1281 plen = strlen(path);
1282
1283 if (plen == 0)
1284 return plen;
1285
1286 /* disregard trailing slashes */
1287 p = path + plen - 1;
1288 while ((*p == '/') && (p > path))
1289 p--;
1290
1291 /* walk backward until we find the next slash or hit beginning */
1292 while ((*p != '/') && (p > path))
1293 p--;
1294
1295 /* did we find a slash? Then increment to include it in path */
1296 if (*p == '/')
1297 p++;
1298
1299 return p - path;
1300}
1301
1302/**
1303 * audit_compare_dname_path - compare given dentry name with last component in
1304 * given path. Return of 0 indicates a match.
1305 * @dname: dentry name that we're comparing
1306 * @path: full pathname that we're comparing
1307 * @parentlen: length of the parent if known. Passing in AUDIT_NAME_FULL
1308 * here indicates that we must compute this value.
1309 */
1310int audit_compare_dname_path(const struct qstr *dname, const char *path, int parentlen)
1311{
1312 int dlen, pathlen;
1313 const char *p;
1314
1315 dlen = dname->len;
1316 pathlen = strlen(path);
1317 if (pathlen < dlen)
1318 return 1;
1319
1320 parentlen = parentlen == AUDIT_NAME_FULL ? parent_len(path) : parentlen;
1321 if (pathlen - parentlen != dlen)
1322 return 1;
1323
1324 p = path + parentlen;
1325
1326 return strncmp(p, dname->name, dlen);
1327}
1328
1329int audit_filter(int msgtype, unsigned int listtype)
1330{
1331 struct audit_entry *e;
1332 int ret = 1; /* Audit by default */
1333
1334 rcu_read_lock();
1335 list_for_each_entry_rcu(e, &audit_filter_list[listtype], list) {
1336 int i, result = 0;
1337
1338 for (i = 0; i < e->rule.field_count; i++) {
1339 struct audit_field *f = &e->rule.fields[i];
1340 pid_t pid;
1341 u32 sid;
1342
1343 switch (f->type) {
1344 case AUDIT_PID:
1345 pid = task_pid_nr(current);
1346 result = audit_comparator(pid, f->op, f->val);
1347 break;
1348 case AUDIT_UID:
1349 result = audit_uid_comparator(current_uid(), f->op, f->uid);
1350 break;
1351 case AUDIT_GID:
1352 result = audit_gid_comparator(current_gid(), f->op, f->gid);
1353 break;
1354 case AUDIT_LOGINUID:
1355 result = audit_uid_comparator(audit_get_loginuid(current),
1356 f->op, f->uid);
1357 break;
1358 case AUDIT_LOGINUID_SET:
1359 result = audit_comparator(audit_loginuid_set(current),
1360 f->op, f->val);
1361 break;
1362 case AUDIT_MSGTYPE:
1363 result = audit_comparator(msgtype, f->op, f->val);
1364 break;
1365 case AUDIT_SUBJ_USER:
1366 case AUDIT_SUBJ_ROLE:
1367 case AUDIT_SUBJ_TYPE:
1368 case AUDIT_SUBJ_SEN:
1369 case AUDIT_SUBJ_CLR:
1370 if (f->lsm_rule) {
1371 security_current_getsecid_subj(&sid);
1372 result = security_audit_rule_match(sid,
1373 f->type, f->op, f->lsm_rule);
1374 }
1375 break;
1376 case AUDIT_EXE:
1377 result = audit_exe_compare(current, e->rule.exe);
1378 if (f->op == Audit_not_equal)
1379 result = !result;
1380 break;
1381 default:
1382 goto unlock_and_return;
1383 }
1384 if (result < 0) /* error */
1385 goto unlock_and_return;
1386 if (!result)
1387 break;
1388 }
1389 if (result > 0) {
1390 if (e->rule.action == AUDIT_NEVER || listtype == AUDIT_FILTER_EXCLUDE)
1391 ret = 0;
1392 break;
1393 }
1394 }
1395unlock_and_return:
1396 rcu_read_unlock();
1397 return ret;
1398}
1399
1400static int update_lsm_rule(struct audit_krule *r)
1401{
1402 struct audit_entry *entry = container_of(r, struct audit_entry, rule);
1403 struct audit_entry *nentry;
1404 int err = 0;
1405
1406 if (!security_audit_rule_known(r))
1407 return 0;
1408
1409 nentry = audit_dupe_rule(r);
1410 if (entry->rule.exe)
1411 audit_remove_mark(entry->rule.exe);
1412 if (IS_ERR(nentry)) {
1413 /* save the first error encountered for the
1414 * return value */
1415 err = PTR_ERR(nentry);
1416 audit_panic("error updating LSM filters");
1417 if (r->watch)
1418 list_del(&r->rlist);
1419 list_del_rcu(&entry->list);
1420 list_del(&r->list);
1421 } else {
1422 if (r->watch || r->tree)
1423 list_replace_init(&r->rlist, &nentry->rule.rlist);
1424 list_replace_rcu(&entry->list, &nentry->list);
1425 list_replace(&r->list, &nentry->rule.list);
1426 }
1427 call_rcu(&entry->rcu, audit_free_rule_rcu);
1428
1429 return err;
1430}
1431
1432/* This function will re-initialize the lsm_rule field of all applicable rules.
1433 * It will traverse the filter lists serarching for rules that contain LSM
1434 * specific filter fields. When such a rule is found, it is copied, the
1435 * LSM field is re-initialized, and the old rule is replaced with the
1436 * updated rule. */
1437int audit_update_lsm_rules(void)
1438{
1439 struct audit_krule *r, *n;
1440 int i, err = 0;
1441
1442 /* audit_filter_mutex synchronizes the writers */
1443 mutex_lock(&audit_filter_mutex);
1444
1445 for (i = 0; i < AUDIT_NR_FILTERS; i++) {
1446 list_for_each_entry_safe(r, n, &audit_rules_list[i], list) {
1447 int res = update_lsm_rule(r);
1448 if (!err)
1449 err = res;
1450 }
1451 }
1452 mutex_unlock(&audit_filter_mutex);
1453
1454 return err;
1455}
1/* auditfilter.c -- filtering of audit events
2 *
3 * Copyright 2003-2004 Red Hat, Inc.
4 * Copyright 2005 Hewlett-Packard Development Company, L.P.
5 * Copyright 2005 IBM Corporation
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 */
21
22#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#if AUDIT_NR_FILTERS != 6
60#error Fix audit_filter_list initialiser
61#endif
62};
63static struct list_head audit_rules_list[AUDIT_NR_FILTERS] = {
64 LIST_HEAD_INIT(audit_rules_list[0]),
65 LIST_HEAD_INIT(audit_rules_list[1]),
66 LIST_HEAD_INIT(audit_rules_list[2]),
67 LIST_HEAD_INIT(audit_rules_list[3]),
68 LIST_HEAD_INIT(audit_rules_list[4]),
69 LIST_HEAD_INIT(audit_rules_list[5]),
70};
71
72DEFINE_MUTEX(audit_filter_mutex);
73
74static inline void audit_free_rule(struct audit_entry *e)
75{
76 int i;
77 struct audit_krule *erule = &e->rule;
78
79 /* some rules don't have associated watches */
80 if (erule->watch)
81 audit_put_watch(erule->watch);
82 if (erule->fields)
83 for (i = 0; i < erule->field_count; i++) {
84 struct audit_field *f = &erule->fields[i];
85 kfree(f->lsm_str);
86 security_audit_rule_free(f->lsm_rule);
87 }
88 kfree(erule->fields);
89 kfree(erule->filterkey);
90 kfree(e);
91}
92
93void audit_free_rule_rcu(struct rcu_head *head)
94{
95 struct audit_entry *e = container_of(head, struct audit_entry, rcu);
96 audit_free_rule(e);
97}
98
99/* Initialize an audit filterlist entry. */
100static inline struct audit_entry *audit_init_entry(u32 field_count)
101{
102 struct audit_entry *entry;
103 struct audit_field *fields;
104
105 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
106 if (unlikely(!entry))
107 return NULL;
108
109 fields = kzalloc(sizeof(*fields) * field_count, GFP_KERNEL);
110 if (unlikely(!fields)) {
111 kfree(entry);
112 return NULL;
113 }
114 entry->rule.fields = fields;
115
116 return entry;
117}
118
119/* Unpack a filter field's string representation from user-space
120 * buffer. */
121char *audit_unpack_string(void **bufp, size_t *remain, size_t len)
122{
123 char *str;
124
125 if (!*bufp || (len == 0) || (len > *remain))
126 return ERR_PTR(-EINVAL);
127
128 /* Of the currently implemented string fields, PATH_MAX
129 * defines the longest valid length.
130 */
131 if (len > PATH_MAX)
132 return ERR_PTR(-ENAMETOOLONG);
133
134 str = kmalloc(len + 1, GFP_KERNEL);
135 if (unlikely(!str))
136 return ERR_PTR(-ENOMEM);
137
138 memcpy(str, *bufp, len);
139 str[len] = 0;
140 *bufp += len;
141 *remain -= len;
142
143 return str;
144}
145
146/* Translate an inode field to kernel respresentation. */
147static inline int audit_to_inode(struct audit_krule *krule,
148 struct audit_field *f)
149{
150 if (krule->listnr != AUDIT_FILTER_EXIT ||
151 krule->watch || krule->inode_f || krule->tree ||
152 (f->op != Audit_equal && f->op != Audit_not_equal))
153 return -EINVAL;
154
155 krule->inode_f = f;
156 return 0;
157}
158
159static __u32 *classes[AUDIT_SYSCALL_CLASSES];
160
161int __init audit_register_class(int class, unsigned *list)
162{
163 __u32 *p = kzalloc(AUDIT_BITMASK_SIZE * sizeof(__u32), GFP_KERNEL);
164 if (!p)
165 return -ENOMEM;
166 while (*list != ~0U) {
167 unsigned n = *list++;
168 if (n >= AUDIT_BITMASK_SIZE * 32 - AUDIT_SYSCALL_CLASSES) {
169 kfree(p);
170 return -EINVAL;
171 }
172 p[AUDIT_WORD(n)] |= AUDIT_BIT(n);
173 }
174 if (class >= AUDIT_SYSCALL_CLASSES || classes[class]) {
175 kfree(p);
176 return -EINVAL;
177 }
178 classes[class] = p;
179 return 0;
180}
181
182int audit_match_class(int class, unsigned syscall)
183{
184 if (unlikely(syscall >= AUDIT_BITMASK_SIZE * 32))
185 return 0;
186 if (unlikely(class >= AUDIT_SYSCALL_CLASSES || !classes[class]))
187 return 0;
188 return classes[class][AUDIT_WORD(syscall)] & AUDIT_BIT(syscall);
189}
190
191#ifdef CONFIG_AUDITSYSCALL
192static inline int audit_match_class_bits(int class, u32 *mask)
193{
194 int i;
195
196 if (classes[class]) {
197 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
198 if (mask[i] & classes[class][i])
199 return 0;
200 }
201 return 1;
202}
203
204static int audit_match_signal(struct audit_entry *entry)
205{
206 struct audit_field *arch = entry->rule.arch_f;
207
208 if (!arch) {
209 /* When arch is unspecified, we must check both masks on biarch
210 * as syscall number alone is ambiguous. */
211 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
212 entry->rule.mask) &&
213 audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
214 entry->rule.mask));
215 }
216
217 switch(audit_classify_arch(arch->val)) {
218 case 0: /* native */
219 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
220 entry->rule.mask));
221 case 1: /* 32bit on biarch */
222 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
223 entry->rule.mask));
224 default:
225 return 1;
226 }
227}
228#endif
229
230/* Common user-space to kernel rule translation. */
231static inline struct audit_entry *audit_to_entry_common(struct audit_rule_data *rule)
232{
233 unsigned listnr;
234 struct audit_entry *entry;
235 int i, err;
236
237 err = -EINVAL;
238 listnr = rule->flags & ~AUDIT_FILTER_PREPEND;
239 switch(listnr) {
240 default:
241 goto exit_err;
242#ifdef CONFIG_AUDITSYSCALL
243 case AUDIT_FILTER_ENTRY:
244 if (rule->action == AUDIT_ALWAYS)
245 goto exit_err;
246 case AUDIT_FILTER_EXIT:
247 case AUDIT_FILTER_TASK:
248#endif
249 case AUDIT_FILTER_USER:
250 case AUDIT_FILTER_TYPE:
251 ;
252 }
253 if (unlikely(rule->action == AUDIT_POSSIBLE)) {
254 pr_err("AUDIT_POSSIBLE is deprecated\n");
255 goto exit_err;
256 }
257 if (rule->action != AUDIT_NEVER && rule->action != AUDIT_ALWAYS)
258 goto exit_err;
259 if (rule->field_count > AUDIT_MAX_FIELDS)
260 goto exit_err;
261
262 err = -ENOMEM;
263 entry = audit_init_entry(rule->field_count);
264 if (!entry)
265 goto exit_err;
266
267 entry->rule.flags = rule->flags & AUDIT_FILTER_PREPEND;
268 entry->rule.listnr = listnr;
269 entry->rule.action = rule->action;
270 entry->rule.field_count = rule->field_count;
271
272 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
273 entry->rule.mask[i] = rule->mask[i];
274
275 for (i = 0; i < AUDIT_SYSCALL_CLASSES; i++) {
276 int bit = AUDIT_BITMASK_SIZE * 32 - i - 1;
277 __u32 *p = &entry->rule.mask[AUDIT_WORD(bit)];
278 __u32 *class;
279
280 if (!(*p & AUDIT_BIT(bit)))
281 continue;
282 *p &= ~AUDIT_BIT(bit);
283 class = classes[i];
284 if (class) {
285 int j;
286 for (j = 0; j < AUDIT_BITMASK_SIZE; j++)
287 entry->rule.mask[j] |= class[j];
288 }
289 }
290
291 return entry;
292
293exit_err:
294 return ERR_PTR(err);
295}
296
297static u32 audit_ops[] =
298{
299 [Audit_equal] = AUDIT_EQUAL,
300 [Audit_not_equal] = AUDIT_NOT_EQUAL,
301 [Audit_bitmask] = AUDIT_BIT_MASK,
302 [Audit_bittest] = AUDIT_BIT_TEST,
303 [Audit_lt] = AUDIT_LESS_THAN,
304 [Audit_gt] = AUDIT_GREATER_THAN,
305 [Audit_le] = AUDIT_LESS_THAN_OR_EQUAL,
306 [Audit_ge] = AUDIT_GREATER_THAN_OR_EQUAL,
307};
308
309static u32 audit_to_op(u32 op)
310{
311 u32 n;
312 for (n = Audit_equal; n < Audit_bad && audit_ops[n] != op; n++)
313 ;
314 return n;
315}
316
317/* check if an audit field is valid */
318static int audit_field_valid(struct audit_entry *entry, struct audit_field *f)
319{
320 switch(f->type) {
321 case AUDIT_MSGTYPE:
322 if (entry->rule.listnr != AUDIT_FILTER_TYPE &&
323 entry->rule.listnr != AUDIT_FILTER_USER)
324 return -EINVAL;
325 break;
326 };
327
328 switch(f->type) {
329 default:
330 return -EINVAL;
331 case AUDIT_UID:
332 case AUDIT_EUID:
333 case AUDIT_SUID:
334 case AUDIT_FSUID:
335 case AUDIT_LOGINUID:
336 case AUDIT_OBJ_UID:
337 case AUDIT_GID:
338 case AUDIT_EGID:
339 case AUDIT_SGID:
340 case AUDIT_FSGID:
341 case AUDIT_OBJ_GID:
342 case AUDIT_PID:
343 case AUDIT_PERS:
344 case AUDIT_MSGTYPE:
345 case AUDIT_PPID:
346 case AUDIT_DEVMAJOR:
347 case AUDIT_DEVMINOR:
348 case AUDIT_EXIT:
349 case AUDIT_SUCCESS:
350 case AUDIT_INODE:
351 /* bit ops are only useful on syscall args */
352 if (f->op == Audit_bitmask || f->op == Audit_bittest)
353 return -EINVAL;
354 break;
355 case AUDIT_ARG0:
356 case AUDIT_ARG1:
357 case AUDIT_ARG2:
358 case AUDIT_ARG3:
359 case AUDIT_SUBJ_USER:
360 case AUDIT_SUBJ_ROLE:
361 case AUDIT_SUBJ_TYPE:
362 case AUDIT_SUBJ_SEN:
363 case AUDIT_SUBJ_CLR:
364 case AUDIT_OBJ_USER:
365 case AUDIT_OBJ_ROLE:
366 case AUDIT_OBJ_TYPE:
367 case AUDIT_OBJ_LEV_LOW:
368 case AUDIT_OBJ_LEV_HIGH:
369 case AUDIT_WATCH:
370 case AUDIT_DIR:
371 case AUDIT_FILTERKEY:
372 break;
373 case AUDIT_LOGINUID_SET:
374 if ((f->val != 0) && (f->val != 1))
375 return -EINVAL;
376 /* FALL THROUGH */
377 case AUDIT_ARCH:
378 if (f->op != Audit_not_equal && f->op != Audit_equal)
379 return -EINVAL;
380 break;
381 case AUDIT_PERM:
382 if (f->val & ~15)
383 return -EINVAL;
384 break;
385 case AUDIT_FILETYPE:
386 if (f->val & ~S_IFMT)
387 return -EINVAL;
388 break;
389 case AUDIT_FIELD_COMPARE:
390 if (f->val > AUDIT_MAX_FIELD_COMPARE)
391 return -EINVAL;
392 break;
393 };
394 return 0;
395}
396
397/* Translate struct audit_rule_data to kernel's rule respresentation. */
398static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
399 size_t datasz)
400{
401 int err = 0;
402 struct audit_entry *entry;
403 void *bufp;
404 size_t remain = datasz - sizeof(struct audit_rule_data);
405 int i;
406 char *str;
407
408 entry = audit_to_entry_common(data);
409 if (IS_ERR(entry))
410 goto exit_nofree;
411
412 bufp = data->buf;
413 entry->rule.vers_ops = 2;
414 for (i = 0; i < data->field_count; i++) {
415 struct audit_field *f = &entry->rule.fields[i];
416
417 err = -EINVAL;
418
419 f->op = audit_to_op(data->fieldflags[i]);
420 if (f->op == Audit_bad)
421 goto exit_free;
422
423 f->type = data->fields[i];
424 f->val = data->values[i];
425 f->uid = INVALID_UID;
426 f->gid = INVALID_GID;
427 f->lsm_str = NULL;
428 f->lsm_rule = NULL;
429
430 /* Support legacy tests for a valid loginuid */
431 if ((f->type == AUDIT_LOGINUID) && (f->val == AUDIT_UID_UNSET)) {
432 f->type = AUDIT_LOGINUID_SET;
433 f->val = 0;
434 }
435
436 if ((f->type == AUDIT_PID) || (f->type == AUDIT_PPID)) {
437 struct pid *pid;
438 rcu_read_lock();
439 pid = find_vpid(f->val);
440 if (!pid) {
441 rcu_read_unlock();
442 err = -ESRCH;
443 goto exit_free;
444 }
445 f->val = pid_nr(pid);
446 rcu_read_unlock();
447 }
448
449 err = audit_field_valid(entry, f);
450 if (err)
451 goto exit_free;
452
453 err = -EINVAL;
454 switch (f->type) {
455 case AUDIT_LOGINUID:
456 case AUDIT_UID:
457 case AUDIT_EUID:
458 case AUDIT_SUID:
459 case AUDIT_FSUID:
460 case AUDIT_OBJ_UID:
461 f->uid = make_kuid(current_user_ns(), f->val);
462 if (!uid_valid(f->uid))
463 goto exit_free;
464 break;
465 case AUDIT_GID:
466 case AUDIT_EGID:
467 case AUDIT_SGID:
468 case AUDIT_FSGID:
469 case AUDIT_OBJ_GID:
470 f->gid = make_kgid(current_user_ns(), f->val);
471 if (!gid_valid(f->gid))
472 goto exit_free;
473 break;
474 case AUDIT_ARCH:
475 entry->rule.arch_f = f;
476 break;
477 case AUDIT_SUBJ_USER:
478 case AUDIT_SUBJ_ROLE:
479 case AUDIT_SUBJ_TYPE:
480 case AUDIT_SUBJ_SEN:
481 case AUDIT_SUBJ_CLR:
482 case AUDIT_OBJ_USER:
483 case AUDIT_OBJ_ROLE:
484 case AUDIT_OBJ_TYPE:
485 case AUDIT_OBJ_LEV_LOW:
486 case AUDIT_OBJ_LEV_HIGH:
487 str = audit_unpack_string(&bufp, &remain, f->val);
488 if (IS_ERR(str))
489 goto exit_free;
490 entry->rule.buflen += f->val;
491
492 err = security_audit_rule_init(f->type, f->op, str,
493 (void **)&f->lsm_rule);
494 /* Keep currently invalid fields around in case they
495 * become valid after a policy reload. */
496 if (err == -EINVAL) {
497 pr_warn("audit rule for LSM \'%s\' is invalid\n",
498 str);
499 err = 0;
500 }
501 if (err) {
502 kfree(str);
503 goto exit_free;
504 } else
505 f->lsm_str = str;
506 break;
507 case AUDIT_WATCH:
508 str = audit_unpack_string(&bufp, &remain, f->val);
509 if (IS_ERR(str))
510 goto exit_free;
511 entry->rule.buflen += f->val;
512
513 err = audit_to_watch(&entry->rule, str, f->val, f->op);
514 if (err) {
515 kfree(str);
516 goto exit_free;
517 }
518 break;
519 case AUDIT_DIR:
520 str = audit_unpack_string(&bufp, &remain, f->val);
521 if (IS_ERR(str))
522 goto exit_free;
523 entry->rule.buflen += f->val;
524
525 err = audit_make_tree(&entry->rule, str, f->op);
526 kfree(str);
527 if (err)
528 goto exit_free;
529 break;
530 case AUDIT_INODE:
531 err = audit_to_inode(&entry->rule, f);
532 if (err)
533 goto exit_free;
534 break;
535 case AUDIT_FILTERKEY:
536 if (entry->rule.filterkey || f->val > AUDIT_MAX_KEY_LEN)
537 goto exit_free;
538 str = audit_unpack_string(&bufp, &remain, f->val);
539 if (IS_ERR(str))
540 goto exit_free;
541 entry->rule.buflen += f->val;
542 entry->rule.filterkey = str;
543 break;
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 if (entry->rule.watch)
555 audit_put_watch(entry->rule.watch); /* matches initial get */
556 if (entry->rule.tree)
557 audit_put_tree(entry->rule.tree); /* that's the temporary one */
558 audit_free_rule(entry);
559 return ERR_PTR(err);
560}
561
562/* Pack a filter field's string representation into data block. */
563static inline size_t audit_pack_string(void **bufp, const char *str)
564{
565 size_t len = strlen(str);
566
567 memcpy(*bufp, str, len);
568 *bufp += len;
569
570 return len;
571}
572
573/* Translate kernel rule respresentation to struct audit_rule_data. */
574static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule)
575{
576 struct audit_rule_data *data;
577 void *bufp;
578 int i;
579
580 data = kmalloc(sizeof(*data) + krule->buflen, GFP_KERNEL);
581 if (unlikely(!data))
582 return NULL;
583 memset(data, 0, sizeof(*data));
584
585 data->flags = krule->flags | krule->listnr;
586 data->action = krule->action;
587 data->field_count = krule->field_count;
588 bufp = data->buf;
589 for (i = 0; i < data->field_count; i++) {
590 struct audit_field *f = &krule->fields[i];
591
592 data->fields[i] = f->type;
593 data->fieldflags[i] = audit_ops[f->op];
594 switch(f->type) {
595 case AUDIT_SUBJ_USER:
596 case AUDIT_SUBJ_ROLE:
597 case AUDIT_SUBJ_TYPE:
598 case AUDIT_SUBJ_SEN:
599 case AUDIT_SUBJ_CLR:
600 case AUDIT_OBJ_USER:
601 case AUDIT_OBJ_ROLE:
602 case AUDIT_OBJ_TYPE:
603 case AUDIT_OBJ_LEV_LOW:
604 case AUDIT_OBJ_LEV_HIGH:
605 data->buflen += data->values[i] =
606 audit_pack_string(&bufp, f->lsm_str);
607 break;
608 case AUDIT_WATCH:
609 data->buflen += data->values[i] =
610 audit_pack_string(&bufp,
611 audit_watch_path(krule->watch));
612 break;
613 case AUDIT_DIR:
614 data->buflen += data->values[i] =
615 audit_pack_string(&bufp,
616 audit_tree_path(krule->tree));
617 break;
618 case AUDIT_FILTERKEY:
619 data->buflen += data->values[i] =
620 audit_pack_string(&bufp, krule->filterkey);
621 break;
622 default:
623 data->values[i] = f->val;
624 }
625 }
626 for (i = 0; i < AUDIT_BITMASK_SIZE; i++) data->mask[i] = krule->mask[i];
627
628 return data;
629}
630
631/* Compare two rules in kernel format. Considered success if rules
632 * don't match. */
633static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
634{
635 int i;
636
637 if (a->flags != b->flags ||
638 a->listnr != b->listnr ||
639 a->action != b->action ||
640 a->field_count != b->field_count)
641 return 1;
642
643 for (i = 0; i < a->field_count; i++) {
644 if (a->fields[i].type != b->fields[i].type ||
645 a->fields[i].op != b->fields[i].op)
646 return 1;
647
648 switch(a->fields[i].type) {
649 case AUDIT_SUBJ_USER:
650 case AUDIT_SUBJ_ROLE:
651 case AUDIT_SUBJ_TYPE:
652 case AUDIT_SUBJ_SEN:
653 case AUDIT_SUBJ_CLR:
654 case AUDIT_OBJ_USER:
655 case AUDIT_OBJ_ROLE:
656 case AUDIT_OBJ_TYPE:
657 case AUDIT_OBJ_LEV_LOW:
658 case AUDIT_OBJ_LEV_HIGH:
659 if (strcmp(a->fields[i].lsm_str, b->fields[i].lsm_str))
660 return 1;
661 break;
662 case AUDIT_WATCH:
663 if (strcmp(audit_watch_path(a->watch),
664 audit_watch_path(b->watch)))
665 return 1;
666 break;
667 case AUDIT_DIR:
668 if (strcmp(audit_tree_path(a->tree),
669 audit_tree_path(b->tree)))
670 return 1;
671 break;
672 case AUDIT_FILTERKEY:
673 /* both filterkeys exist based on above type compare */
674 if (strcmp(a->filterkey, b->filterkey))
675 return 1;
676 break;
677 case AUDIT_UID:
678 case AUDIT_EUID:
679 case AUDIT_SUID:
680 case AUDIT_FSUID:
681 case AUDIT_LOGINUID:
682 case AUDIT_OBJ_UID:
683 if (!uid_eq(a->fields[i].uid, b->fields[i].uid))
684 return 1;
685 break;
686 case AUDIT_GID:
687 case AUDIT_EGID:
688 case AUDIT_SGID:
689 case AUDIT_FSGID:
690 case AUDIT_OBJ_GID:
691 if (!gid_eq(a->fields[i].gid, b->fields[i].gid))
692 return 1;
693 break;
694 default:
695 if (a->fields[i].val != b->fields[i].val)
696 return 1;
697 }
698 }
699
700 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
701 if (a->mask[i] != b->mask[i])
702 return 1;
703
704 return 0;
705}
706
707/* Duplicate LSM field information. The lsm_rule is opaque, so must be
708 * re-initialized. */
709static inline int audit_dupe_lsm_field(struct audit_field *df,
710 struct audit_field *sf)
711{
712 int ret = 0;
713 char *lsm_str;
714
715 /* our own copy of lsm_str */
716 lsm_str = kstrdup(sf->lsm_str, GFP_KERNEL);
717 if (unlikely(!lsm_str))
718 return -ENOMEM;
719 df->lsm_str = lsm_str;
720
721 /* our own (refreshed) copy of lsm_rule */
722 ret = security_audit_rule_init(df->type, df->op, df->lsm_str,
723 (void **)&df->lsm_rule);
724 /* Keep currently invalid fields around in case they
725 * become valid after a policy reload. */
726 if (ret == -EINVAL) {
727 pr_warn("audit rule for LSM \'%s\' is invalid\n",
728 df->lsm_str);
729 ret = 0;
730 }
731
732 return ret;
733}
734
735/* Duplicate an audit rule. This will be a deep copy with the exception
736 * of the watch - that pointer is carried over. The LSM specific fields
737 * will be updated in the copy. The point is to be able to replace the old
738 * rule with the new rule in the filterlist, then free the old rule.
739 * The rlist element is undefined; list manipulations are handled apart from
740 * the initial copy. */
741struct audit_entry *audit_dupe_rule(struct audit_krule *old)
742{
743 u32 fcount = old->field_count;
744 struct audit_entry *entry;
745 struct audit_krule *new;
746 char *fk;
747 int i, err = 0;
748
749 entry = audit_init_entry(fcount);
750 if (unlikely(!entry))
751 return ERR_PTR(-ENOMEM);
752
753 new = &entry->rule;
754 new->vers_ops = old->vers_ops;
755 new->flags = old->flags;
756 new->listnr = old->listnr;
757 new->action = old->action;
758 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
759 new->mask[i] = old->mask[i];
760 new->prio = old->prio;
761 new->buflen = old->buflen;
762 new->inode_f = old->inode_f;
763 new->field_count = old->field_count;
764
765 /*
766 * note that we are OK with not refcounting here; audit_match_tree()
767 * never dereferences tree and we can't get false positives there
768 * since we'd have to have rule gone from the list *and* removed
769 * before the chunks found by lookup had been allocated, i.e. before
770 * the beginning of list scan.
771 */
772 new->tree = old->tree;
773 memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount);
774
775 /* deep copy this information, updating the lsm_rule fields, because
776 * the originals will all be freed when the old rule is freed. */
777 for (i = 0; i < fcount; i++) {
778 switch (new->fields[i].type) {
779 case AUDIT_SUBJ_USER:
780 case AUDIT_SUBJ_ROLE:
781 case AUDIT_SUBJ_TYPE:
782 case AUDIT_SUBJ_SEN:
783 case AUDIT_SUBJ_CLR:
784 case AUDIT_OBJ_USER:
785 case AUDIT_OBJ_ROLE:
786 case AUDIT_OBJ_TYPE:
787 case AUDIT_OBJ_LEV_LOW:
788 case AUDIT_OBJ_LEV_HIGH:
789 err = audit_dupe_lsm_field(&new->fields[i],
790 &old->fields[i]);
791 break;
792 case AUDIT_FILTERKEY:
793 fk = kstrdup(old->filterkey, GFP_KERNEL);
794 if (unlikely(!fk))
795 err = -ENOMEM;
796 else
797 new->filterkey = fk;
798 }
799 if (err) {
800 audit_free_rule(entry);
801 return ERR_PTR(err);
802 }
803 }
804
805 if (old->watch) {
806 audit_get_watch(old->watch);
807 new->watch = old->watch;
808 }
809
810 return entry;
811}
812
813/* Find an existing audit rule.
814 * Caller must hold audit_filter_mutex to prevent stale rule data. */
815static struct audit_entry *audit_find_rule(struct audit_entry *entry,
816 struct list_head **p)
817{
818 struct audit_entry *e, *found = NULL;
819 struct list_head *list;
820 int h;
821
822 if (entry->rule.inode_f) {
823 h = audit_hash_ino(entry->rule.inode_f->val);
824 *p = list = &audit_inode_hash[h];
825 } else if (entry->rule.watch) {
826 /* we don't know the inode number, so must walk entire hash */
827 for (h = 0; h < AUDIT_INODE_BUCKETS; h++) {
828 list = &audit_inode_hash[h];
829 list_for_each_entry(e, list, list)
830 if (!audit_compare_rule(&entry->rule, &e->rule)) {
831 found = e;
832 goto out;
833 }
834 }
835 goto out;
836 } else {
837 *p = list = &audit_filter_list[entry->rule.listnr];
838 }
839
840 list_for_each_entry(e, list, list)
841 if (!audit_compare_rule(&entry->rule, &e->rule)) {
842 found = e;
843 goto out;
844 }
845
846out:
847 return found;
848}
849
850static u64 prio_low = ~0ULL/2;
851static u64 prio_high = ~0ULL/2 - 1;
852
853/* Add rule to given filterlist if not a duplicate. */
854static inline int audit_add_rule(struct audit_entry *entry)
855{
856 struct audit_entry *e;
857 struct audit_watch *watch = entry->rule.watch;
858 struct audit_tree *tree = entry->rule.tree;
859 struct list_head *list;
860 int err;
861#ifdef CONFIG_AUDITSYSCALL
862 int dont_count = 0;
863
864 /* If either of these, don't count towards total */
865 if (entry->rule.listnr == AUDIT_FILTER_USER ||
866 entry->rule.listnr == AUDIT_FILTER_TYPE)
867 dont_count = 1;
868#endif
869
870 mutex_lock(&audit_filter_mutex);
871 e = audit_find_rule(entry, &list);
872 if (e) {
873 mutex_unlock(&audit_filter_mutex);
874 err = -EEXIST;
875 /* normally audit_add_tree_rule() will free it on failure */
876 if (tree)
877 audit_put_tree(tree);
878 goto error;
879 }
880
881 if (watch) {
882 /* audit_filter_mutex is dropped and re-taken during this call */
883 err = audit_add_watch(&entry->rule, &list);
884 if (err) {
885 mutex_unlock(&audit_filter_mutex);
886 /*
887 * normally audit_add_tree_rule() will free it
888 * on failure
889 */
890 if (tree)
891 audit_put_tree(tree);
892 goto error;
893 }
894 }
895 if (tree) {
896 err = audit_add_tree_rule(&entry->rule);
897 if (err) {
898 mutex_unlock(&audit_filter_mutex);
899 goto error;
900 }
901 }
902
903 entry->rule.prio = ~0ULL;
904 if (entry->rule.listnr == AUDIT_FILTER_EXIT) {
905 if (entry->rule.flags & AUDIT_FILTER_PREPEND)
906 entry->rule.prio = ++prio_high;
907 else
908 entry->rule.prio = --prio_low;
909 }
910
911 if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
912 list_add(&entry->rule.list,
913 &audit_rules_list[entry->rule.listnr]);
914 list_add_rcu(&entry->list, list);
915 entry->rule.flags &= ~AUDIT_FILTER_PREPEND;
916 } else {
917 list_add_tail(&entry->rule.list,
918 &audit_rules_list[entry->rule.listnr]);
919 list_add_tail_rcu(&entry->list, list);
920 }
921#ifdef CONFIG_AUDITSYSCALL
922 if (!dont_count)
923 audit_n_rules++;
924
925 if (!audit_match_signal(entry))
926 audit_signals++;
927#endif
928 mutex_unlock(&audit_filter_mutex);
929
930 return 0;
931
932error:
933 if (watch)
934 audit_put_watch(watch); /* tmp watch, matches initial get */
935 return err;
936}
937
938/* Remove an existing rule from filterlist. */
939static inline int audit_del_rule(struct audit_entry *entry)
940{
941 struct audit_entry *e;
942 struct audit_watch *watch = entry->rule.watch;
943 struct audit_tree *tree = entry->rule.tree;
944 struct list_head *list;
945 int ret = 0;
946#ifdef CONFIG_AUDITSYSCALL
947 int dont_count = 0;
948
949 /* If either of these, don't count towards total */
950 if (entry->rule.listnr == AUDIT_FILTER_USER ||
951 entry->rule.listnr == AUDIT_FILTER_TYPE)
952 dont_count = 1;
953#endif
954
955 mutex_lock(&audit_filter_mutex);
956 e = audit_find_rule(entry, &list);
957 if (!e) {
958 mutex_unlock(&audit_filter_mutex);
959 ret = -ENOENT;
960 goto out;
961 }
962
963 if (e->rule.watch)
964 audit_remove_watch_rule(&e->rule);
965
966 if (e->rule.tree)
967 audit_remove_tree_rule(&e->rule);
968
969 list_del_rcu(&e->list);
970 list_del(&e->rule.list);
971 call_rcu(&e->rcu, audit_free_rule_rcu);
972
973#ifdef CONFIG_AUDITSYSCALL
974 if (!dont_count)
975 audit_n_rules--;
976
977 if (!audit_match_signal(entry))
978 audit_signals--;
979#endif
980 mutex_unlock(&audit_filter_mutex);
981
982out:
983 if (watch)
984 audit_put_watch(watch); /* match initial get */
985 if (tree)
986 audit_put_tree(tree); /* that's the temporary one */
987
988 return ret;
989}
990
991/* List rules using struct audit_rule_data. */
992static void audit_list_rules(__u32 portid, int seq, struct sk_buff_head *q)
993{
994 struct sk_buff *skb;
995 struct audit_krule *r;
996 int i;
997
998 /* This is a blocking read, so use audit_filter_mutex instead of rcu
999 * iterator to sync with list writers. */
1000 for (i=0; i<AUDIT_NR_FILTERS; i++) {
1001 list_for_each_entry(r, &audit_rules_list[i], list) {
1002 struct audit_rule_data *data;
1003
1004 data = audit_krule_to_data(r);
1005 if (unlikely(!data))
1006 break;
1007 skb = audit_make_reply(portid, seq, AUDIT_LIST_RULES,
1008 0, 1, data,
1009 sizeof(*data) + data->buflen);
1010 if (skb)
1011 skb_queue_tail(q, skb);
1012 kfree(data);
1013 }
1014 }
1015 skb = audit_make_reply(portid, seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);
1016 if (skb)
1017 skb_queue_tail(q, skb);
1018}
1019
1020/* Log rule additions and removals */
1021static void audit_log_rule_change(char *action, struct audit_krule *rule, int res)
1022{
1023 struct audit_buffer *ab;
1024 uid_t loginuid = from_kuid(&init_user_ns, audit_get_loginuid(current));
1025 unsigned int sessionid = audit_get_sessionid(current);
1026
1027 if (!audit_enabled)
1028 return;
1029
1030 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
1031 if (!ab)
1032 return;
1033 audit_log_format(ab, "auid=%u ses=%u" ,loginuid, sessionid);
1034 audit_log_task_context(ab);
1035 audit_log_format(ab, " op=");
1036 audit_log_string(ab, action);
1037 audit_log_key(ab, rule->filterkey);
1038 audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
1039 audit_log_end(ab);
1040}
1041
1042/**
1043 * audit_rule_change - apply all rules to the specified message type
1044 * @type: audit message type
1045 * @portid: target port id for netlink audit messages
1046 * @seq: netlink audit message sequence (serial) number
1047 * @data: payload data
1048 * @datasz: size of payload data
1049 */
1050int audit_rule_change(int type, __u32 portid, int seq, void *data,
1051 size_t datasz)
1052{
1053 int err = 0;
1054 struct audit_entry *entry;
1055
1056 switch (type) {
1057 case AUDIT_ADD_RULE:
1058 entry = audit_data_to_entry(data, datasz);
1059 if (IS_ERR(entry))
1060 return PTR_ERR(entry);
1061
1062 err = audit_add_rule(entry);
1063 audit_log_rule_change("add rule", &entry->rule, !err);
1064 if (err)
1065 audit_free_rule(entry);
1066 break;
1067 case AUDIT_DEL_RULE:
1068 entry = audit_data_to_entry(data, datasz);
1069 if (IS_ERR(entry))
1070 return PTR_ERR(entry);
1071
1072 err = audit_del_rule(entry);
1073 audit_log_rule_change("remove rule", &entry->rule, !err);
1074 audit_free_rule(entry);
1075 break;
1076 default:
1077 return -EINVAL;
1078 }
1079
1080 return err;
1081}
1082
1083/**
1084 * audit_list_rules_send - list the audit rules
1085 * @request_skb: skb of request we are replying to (used to target the reply)
1086 * @seq: netlink audit message sequence (serial) number
1087 */
1088int audit_list_rules_send(struct sk_buff *request_skb, int seq)
1089{
1090 u32 portid = NETLINK_CB(request_skb).portid;
1091 struct net *net = sock_net(NETLINK_CB(request_skb).sk);
1092 struct task_struct *tsk;
1093 struct audit_netlink_list *dest;
1094 int err = 0;
1095
1096 /* We can't just spew out the rules here because we might fill
1097 * the available socket buffer space and deadlock waiting for
1098 * auditctl to read from it... which isn't ever going to
1099 * happen if we're actually running in the context of auditctl
1100 * trying to _send_ the stuff */
1101
1102 dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL);
1103 if (!dest)
1104 return -ENOMEM;
1105 dest->net = get_net(net);
1106 dest->portid = portid;
1107 skb_queue_head_init(&dest->q);
1108
1109 mutex_lock(&audit_filter_mutex);
1110 audit_list_rules(portid, seq, &dest->q);
1111 mutex_unlock(&audit_filter_mutex);
1112
1113 tsk = kthread_run(audit_send_list, dest, "audit_send_list");
1114 if (IS_ERR(tsk)) {
1115 skb_queue_purge(&dest->q);
1116 kfree(dest);
1117 err = PTR_ERR(tsk);
1118 }
1119
1120 return err;
1121}
1122
1123int audit_comparator(u32 left, u32 op, u32 right)
1124{
1125 switch (op) {
1126 case Audit_equal:
1127 return (left == right);
1128 case Audit_not_equal:
1129 return (left != right);
1130 case Audit_lt:
1131 return (left < right);
1132 case Audit_le:
1133 return (left <= right);
1134 case Audit_gt:
1135 return (left > right);
1136 case Audit_ge:
1137 return (left >= right);
1138 case Audit_bitmask:
1139 return (left & right);
1140 case Audit_bittest:
1141 return ((left & right) == right);
1142 default:
1143 BUG();
1144 return 0;
1145 }
1146}
1147
1148int audit_uid_comparator(kuid_t left, u32 op, kuid_t right)
1149{
1150 switch (op) {
1151 case Audit_equal:
1152 return uid_eq(left, right);
1153 case Audit_not_equal:
1154 return !uid_eq(left, right);
1155 case Audit_lt:
1156 return uid_lt(left, right);
1157 case Audit_le:
1158 return uid_lte(left, right);
1159 case Audit_gt:
1160 return uid_gt(left, right);
1161 case Audit_ge:
1162 return uid_gte(left, right);
1163 case Audit_bitmask:
1164 case Audit_bittest:
1165 default:
1166 BUG();
1167 return 0;
1168 }
1169}
1170
1171int audit_gid_comparator(kgid_t left, u32 op, kgid_t right)
1172{
1173 switch (op) {
1174 case Audit_equal:
1175 return gid_eq(left, right);
1176 case Audit_not_equal:
1177 return !gid_eq(left, right);
1178 case Audit_lt:
1179 return gid_lt(left, right);
1180 case Audit_le:
1181 return gid_lte(left, right);
1182 case Audit_gt:
1183 return gid_gt(left, right);
1184 case Audit_ge:
1185 return gid_gte(left, right);
1186 case Audit_bitmask:
1187 case Audit_bittest:
1188 default:
1189 BUG();
1190 return 0;
1191 }
1192}
1193
1194/**
1195 * parent_len - find the length of the parent portion of a pathname
1196 * @path: pathname of which to determine length
1197 */
1198int parent_len(const char *path)
1199{
1200 int plen;
1201 const char *p;
1202
1203 plen = strlen(path);
1204
1205 if (plen == 0)
1206 return plen;
1207
1208 /* disregard trailing slashes */
1209 p = path + plen - 1;
1210 while ((*p == '/') && (p > path))
1211 p--;
1212
1213 /* walk backward until we find the next slash or hit beginning */
1214 while ((*p != '/') && (p > path))
1215 p--;
1216
1217 /* did we find a slash? Then increment to include it in path */
1218 if (*p == '/')
1219 p++;
1220
1221 return p - path;
1222}
1223
1224/**
1225 * audit_compare_dname_path - compare given dentry name with last component in
1226 * given path. Return of 0 indicates a match.
1227 * @dname: dentry name that we're comparing
1228 * @path: full pathname that we're comparing
1229 * @parentlen: length of the parent if known. Passing in AUDIT_NAME_FULL
1230 * here indicates that we must compute this value.
1231 */
1232int audit_compare_dname_path(const char *dname, const char *path, int parentlen)
1233{
1234 int dlen, pathlen;
1235 const char *p;
1236
1237 dlen = strlen(dname);
1238 pathlen = strlen(path);
1239 if (pathlen < dlen)
1240 return 1;
1241
1242 parentlen = parentlen == AUDIT_NAME_FULL ? parent_len(path) : parentlen;
1243 if (pathlen - parentlen != dlen)
1244 return 1;
1245
1246 p = path + parentlen;
1247
1248 return strncmp(p, dname, dlen);
1249}
1250
1251static int audit_filter_user_rules(struct audit_krule *rule, int type,
1252 enum audit_state *state)
1253{
1254 int i;
1255
1256 for (i = 0; i < rule->field_count; i++) {
1257 struct audit_field *f = &rule->fields[i];
1258 pid_t pid;
1259 int result = 0;
1260 u32 sid;
1261
1262 switch (f->type) {
1263 case AUDIT_PID:
1264 pid = task_pid_nr(current);
1265 result = audit_comparator(pid, f->op, f->val);
1266 break;
1267 case AUDIT_UID:
1268 result = audit_uid_comparator(current_uid(), f->op, f->uid);
1269 break;
1270 case AUDIT_GID:
1271 result = audit_gid_comparator(current_gid(), f->op, f->gid);
1272 break;
1273 case AUDIT_LOGINUID:
1274 result = audit_uid_comparator(audit_get_loginuid(current),
1275 f->op, f->uid);
1276 break;
1277 case AUDIT_LOGINUID_SET:
1278 result = audit_comparator(audit_loginuid_set(current),
1279 f->op, f->val);
1280 break;
1281 case AUDIT_MSGTYPE:
1282 result = audit_comparator(type, f->op, f->val);
1283 break;
1284 case AUDIT_SUBJ_USER:
1285 case AUDIT_SUBJ_ROLE:
1286 case AUDIT_SUBJ_TYPE:
1287 case AUDIT_SUBJ_SEN:
1288 case AUDIT_SUBJ_CLR:
1289 if (f->lsm_rule) {
1290 security_task_getsecid(current, &sid);
1291 result = security_audit_rule_match(sid,
1292 f->type,
1293 f->op,
1294 f->lsm_rule,
1295 NULL);
1296 }
1297 break;
1298 }
1299
1300 if (!result)
1301 return 0;
1302 }
1303 switch (rule->action) {
1304 case AUDIT_NEVER: *state = AUDIT_DISABLED; break;
1305 case AUDIT_ALWAYS: *state = AUDIT_RECORD_CONTEXT; break;
1306 }
1307 return 1;
1308}
1309
1310int audit_filter_user(int type)
1311{
1312 enum audit_state state = AUDIT_DISABLED;
1313 struct audit_entry *e;
1314 int rc, ret;
1315
1316 ret = 1; /* Audit by default */
1317
1318 rcu_read_lock();
1319 list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_USER], list) {
1320 rc = audit_filter_user_rules(&e->rule, type, &state);
1321 if (rc) {
1322 if (rc > 0 && state == AUDIT_DISABLED)
1323 ret = 0;
1324 break;
1325 }
1326 }
1327 rcu_read_unlock();
1328
1329 return ret;
1330}
1331
1332int audit_filter_type(int type)
1333{
1334 struct audit_entry *e;
1335 int result = 0;
1336
1337 rcu_read_lock();
1338 if (list_empty(&audit_filter_list[AUDIT_FILTER_TYPE]))
1339 goto unlock_and_return;
1340
1341 list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_TYPE],
1342 list) {
1343 int i;
1344 for (i = 0; i < e->rule.field_count; i++) {
1345 struct audit_field *f = &e->rule.fields[i];
1346 if (f->type == AUDIT_MSGTYPE) {
1347 result = audit_comparator(type, f->op, f->val);
1348 if (!result)
1349 break;
1350 }
1351 }
1352 if (result)
1353 goto unlock_and_return;
1354 }
1355unlock_and_return:
1356 rcu_read_unlock();
1357 return result;
1358}
1359
1360static int update_lsm_rule(struct audit_krule *r)
1361{
1362 struct audit_entry *entry = container_of(r, struct audit_entry, rule);
1363 struct audit_entry *nentry;
1364 int err = 0;
1365
1366 if (!security_audit_rule_known(r))
1367 return 0;
1368
1369 nentry = audit_dupe_rule(r);
1370 if (IS_ERR(nentry)) {
1371 /* save the first error encountered for the
1372 * return value */
1373 err = PTR_ERR(nentry);
1374 audit_panic("error updating LSM filters");
1375 if (r->watch)
1376 list_del(&r->rlist);
1377 list_del_rcu(&entry->list);
1378 list_del(&r->list);
1379 } else {
1380 if (r->watch || r->tree)
1381 list_replace_init(&r->rlist, &nentry->rule.rlist);
1382 list_replace_rcu(&entry->list, &nentry->list);
1383 list_replace(&r->list, &nentry->rule.list);
1384 }
1385 call_rcu(&entry->rcu, audit_free_rule_rcu);
1386
1387 return err;
1388}
1389
1390/* This function will re-initialize the lsm_rule field of all applicable rules.
1391 * It will traverse the filter lists serarching for rules that contain LSM
1392 * specific filter fields. When such a rule is found, it is copied, the
1393 * LSM field is re-initialized, and the old rule is replaced with the
1394 * updated rule. */
1395int audit_update_lsm_rules(void)
1396{
1397 struct audit_krule *r, *n;
1398 int i, err = 0;
1399
1400 /* audit_filter_mutex synchronizes the writers */
1401 mutex_lock(&audit_filter_mutex);
1402
1403 for (i = 0; i < AUDIT_NR_FILTERS; i++) {
1404 list_for_each_entry_safe(r, n, &audit_rules_list[i], list) {
1405 int res = update_lsm_rule(r);
1406 if (!err)
1407 err = res;
1408 }
1409 }
1410 mutex_unlock(&audit_filter_mutex);
1411
1412 return err;
1413}