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