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Linux 4.13.16
[linux/fpc-iii.git] / kernel / auditfilter.c
blob0b0aa5854dac1ed41959f9383af95d4097ad4646
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> */
52 struct 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 };
63 static 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
72 DEFINE_MUTEX(audit_filter_mutex);
73
74 static void audit_free_lsm_field(struct audit_field *f)
75 {
76 switch (f->type) {
77 case AUDIT_SUBJ_USER:
78 case AUDIT_SUBJ_ROLE:
79 case AUDIT_SUBJ_TYPE:
80 case AUDIT_SUBJ_SEN:
81 case AUDIT_SUBJ_CLR:
82 case AUDIT_OBJ_USER:
83 case AUDIT_OBJ_ROLE:
84 case AUDIT_OBJ_TYPE:
85 case AUDIT_OBJ_LEV_LOW:
86 case AUDIT_OBJ_LEV_HIGH:
87 kfree(f->lsm_str);
88 security_audit_rule_free(f->lsm_rule);
89 }
90 }
91
92 static inline void audit_free_rule(struct audit_entry *e)
93 {
94 int i;
95 struct audit_krule *erule = &e->rule;
96
97 /* some rules don't have associated watches */
98 if (erule->watch)
99 audit_put_watch(erule->watch);
100 if (erule->fields)
101 for (i = 0; i < erule->field_count; i++)
102 audit_free_lsm_field(&erule->fields[i]);
103 kfree(erule->fields);
104 kfree(erule->filterkey);
105 kfree(e);
106 }
107
108 void audit_free_rule_rcu(struct rcu_head *head)
109 {
110 struct audit_entry *e = container_of(head, struct audit_entry, rcu);
111 audit_free_rule(e);
112 }
113
114 /* Initialize an audit filterlist entry. */
115 static inline struct audit_entry *audit_init_entry(u32 field_count)
116 {
117 struct audit_entry *entry;
118 struct audit_field *fields;
119
120 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
121 if (unlikely(!entry))
122 return NULL;
123
124 fields = kcalloc(field_count, sizeof(*fields), GFP_KERNEL);
125 if (unlikely(!fields)) {
126 kfree(entry);
127 return NULL;
128 }
129 entry->rule.fields = fields;
130
131 return entry;
132 }
133
134 /* Unpack a filter field's string representation from user-space
135 * buffer. */
136 char *audit_unpack_string(void **bufp, size_t *remain, size_t len)
137 {
138 char *str;
139
140 if (!*bufp || (len == 0) || (len > *remain))
141 return ERR_PTR(-EINVAL);
142
143 /* Of the currently implemented string fields, PATH_MAX
144 * defines the longest valid length.
145 */
146 if (len > PATH_MAX)
147 return ERR_PTR(-ENAMETOOLONG);
148
149 str = kmalloc(len + 1, GFP_KERNEL);
150 if (unlikely(!str))
151 return ERR_PTR(-ENOMEM);
152
153 memcpy(str, *bufp, len);
154 str[len] = 0;
155 *bufp += len;
156 *remain -= len;
157
158 return str;
159 }
160
161 /* Translate an inode field to kernel representation. */
162 static inline int audit_to_inode(struct audit_krule *krule,
163 struct audit_field *f)
164 {
165 if (krule->listnr != AUDIT_FILTER_EXIT ||
166 krule->inode_f || krule->watch || krule->tree ||
167 (f->op != Audit_equal && f->op != Audit_not_equal))
168 return -EINVAL;
169
170 krule->inode_f = f;
171 return 0;
172 }
173
174 static __u32 *classes[AUDIT_SYSCALL_CLASSES];
175
176 int __init audit_register_class(int class, unsigned *list)
177 {
178 __u32 *p = kcalloc(AUDIT_BITMASK_SIZE, sizeof(__u32), GFP_KERNEL);
179 if (!p)
180 return -ENOMEM;
181 while (*list != ~0U) {
182 unsigned n = *list++;
183 if (n >= AUDIT_BITMASK_SIZE * 32 - AUDIT_SYSCALL_CLASSES) {
184 kfree(p);
185 return -EINVAL;
186 }
187 p[AUDIT_WORD(n)] |= AUDIT_BIT(n);
188 }
189 if (class >= AUDIT_SYSCALL_CLASSES || classes[class]) {
190 kfree(p);
191 return -EINVAL;
192 }
193 classes[class] = p;
194 return 0;
195 }
196
197 int audit_match_class(int class, unsigned syscall)
198 {
199 if (unlikely(syscall >= AUDIT_BITMASK_SIZE * 32))
200 return 0;
201 if (unlikely(class >= AUDIT_SYSCALL_CLASSES || !classes[class]))
202 return 0;
203 return classes[class][AUDIT_WORD(syscall)] & AUDIT_BIT(syscall);
204 }
205
206 #ifdef CONFIG_AUDITSYSCALL
207 static inline int audit_match_class_bits(int class, u32 *mask)
208 {
209 int i;
210
211 if (classes[class]) {
212 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
213 if (mask[i] & classes[class][i])
214 return 0;
215 }
216 return 1;
217 }
218
219 static int audit_match_signal(struct audit_entry *entry)
220 {
221 struct audit_field *arch = entry->rule.arch_f;
222
223 if (!arch) {
224 /* When arch is unspecified, we must check both masks on biarch
225 * as syscall number alone is ambiguous. */
226 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
227 entry->rule.mask) &&
228 audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
229 entry->rule.mask));
230 }
231
232 switch(audit_classify_arch(arch->val)) {
233 case 0: /* native */
234 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
235 entry->rule.mask));
236 case 1: /* 32bit on biarch */
237 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
238 entry->rule.mask));
239 default:
240 return 1;
241 }
242 }
243 #endif
244
245 /* Common user-space to kernel rule translation. */
246 static inline struct audit_entry *audit_to_entry_common(struct audit_rule_data *rule)
247 {
248 unsigned listnr;
249 struct audit_entry *entry;
250 int i, err;
251
252 err = -EINVAL;
253 listnr = rule->flags & ~AUDIT_FILTER_PREPEND;
254 switch(listnr) {
255 default:
256 goto exit_err;
257 #ifdef CONFIG_AUDITSYSCALL
258 case AUDIT_FILTER_ENTRY:
259 if (rule->action == AUDIT_ALWAYS)
260 goto exit_err;
261 case AUDIT_FILTER_EXIT:
262 case AUDIT_FILTER_TASK:
263 #endif
264 case AUDIT_FILTER_USER:
265 case AUDIT_FILTER_TYPE:
266 ;
267 }
268 if (unlikely(rule->action == AUDIT_POSSIBLE)) {
269 pr_err("AUDIT_POSSIBLE is deprecated\n");
270 goto exit_err;
271 }
272 if (rule->action != AUDIT_NEVER && rule->action != AUDIT_ALWAYS)
273 goto exit_err;
274 if (rule->field_count > AUDIT_MAX_FIELDS)
275 goto exit_err;
276
277 err = -ENOMEM;
278 entry = audit_init_entry(rule->field_count);
279 if (!entry)
280 goto exit_err;
281
282 entry->rule.flags = rule->flags & AUDIT_FILTER_PREPEND;
283 entry->rule.listnr = listnr;
284 entry->rule.action = rule->action;
285 entry->rule.field_count = rule->field_count;
286
287 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
288 entry->rule.mask[i] = rule->mask[i];
289
290 for (i = 0; i < AUDIT_SYSCALL_CLASSES; i++) {
291 int bit = AUDIT_BITMASK_SIZE * 32 - i - 1;
292 __u32 *p = &entry->rule.mask[AUDIT_WORD(bit)];
293 __u32 *class;
294
295 if (!(*p & AUDIT_BIT(bit)))
296 continue;
297 *p &= ~AUDIT_BIT(bit);
298 class = classes[i];
299 if (class) {
300 int j;
301 for (j = 0; j < AUDIT_BITMASK_SIZE; j++)
302 entry->rule.mask[j] |= class[j];
303 }
304 }
305
306 return entry;
307
308 exit_err:
309 return ERR_PTR(err);
310 }
311
312 static u32 audit_ops[] =
313 {
314 [Audit_equal] = AUDIT_EQUAL,
315 [Audit_not_equal] = AUDIT_NOT_EQUAL,
316 [Audit_bitmask] = AUDIT_BIT_MASK,
317 [Audit_bittest] = AUDIT_BIT_TEST,
318 [Audit_lt] = AUDIT_LESS_THAN,
319 [Audit_gt] = AUDIT_GREATER_THAN,
320 [Audit_le] = AUDIT_LESS_THAN_OR_EQUAL,
321 [Audit_ge] = AUDIT_GREATER_THAN_OR_EQUAL,
322 };
323
324 static u32 audit_to_op(u32 op)
325 {
326 u32 n;
327 for (n = Audit_equal; n < Audit_bad && audit_ops[n] != op; n++)
328 ;
329 return n;
330 }
331
332 /* check if an audit field is valid */
333 static int audit_field_valid(struct audit_entry *entry, struct audit_field *f)
334 {
335 switch(f->type) {
336 case AUDIT_MSGTYPE:
337 if (entry->rule.listnr != AUDIT_FILTER_TYPE &&
338 entry->rule.listnr != AUDIT_FILTER_USER)
339 return -EINVAL;
340 break;
341 }
342
343 switch(f->type) {
344 default:
345 return -EINVAL;
346 case AUDIT_UID:
347 case AUDIT_EUID:
348 case AUDIT_SUID:
349 case AUDIT_FSUID:
350 case AUDIT_LOGINUID:
351 case AUDIT_OBJ_UID:
352 case AUDIT_GID:
353 case AUDIT_EGID:
354 case AUDIT_SGID:
355 case AUDIT_FSGID:
356 case AUDIT_OBJ_GID:
357 case AUDIT_PID:
358 case AUDIT_PERS:
359 case AUDIT_MSGTYPE:
360 case AUDIT_PPID:
361 case AUDIT_DEVMAJOR:
362 case AUDIT_DEVMINOR:
363 case AUDIT_EXIT:
364 case AUDIT_SUCCESS:
365 case AUDIT_INODE:
366 case AUDIT_SESSIONID:
367 /* bit ops are only useful on syscall args */
368 if (f->op == Audit_bitmask || f->op == Audit_bittest)
369 return -EINVAL;
370 break;
371 case AUDIT_ARG0:
372 case AUDIT_ARG1:
373 case AUDIT_ARG2:
374 case AUDIT_ARG3:
375 case AUDIT_SUBJ_USER:
376 case AUDIT_SUBJ_ROLE:
377 case AUDIT_SUBJ_TYPE:
378 case AUDIT_SUBJ_SEN:
379 case AUDIT_SUBJ_CLR:
380 case AUDIT_OBJ_USER:
381 case AUDIT_OBJ_ROLE:
382 case AUDIT_OBJ_TYPE:
383 case AUDIT_OBJ_LEV_LOW:
384 case AUDIT_OBJ_LEV_HIGH:
385 case AUDIT_WATCH:
386 case AUDIT_DIR:
387 case AUDIT_FILTERKEY:
388 break;
389 case AUDIT_LOGINUID_SET:
390 if ((f->val != 0) && (f->val != 1))
391 return -EINVAL;
392 /* FALL THROUGH */
393 case AUDIT_ARCH:
394 if (f->op != Audit_not_equal && f->op != Audit_equal)
395 return -EINVAL;
396 break;
397 case AUDIT_PERM:
398 if (f->val & ~15)
399 return -EINVAL;
400 break;
401 case AUDIT_FILETYPE:
402 if (f->val & ~S_IFMT)
403 return -EINVAL;
404 break;
405 case AUDIT_FIELD_COMPARE:
406 if (f->val > AUDIT_MAX_FIELD_COMPARE)
407 return -EINVAL;
408 break;
409 case AUDIT_EXE:
410 if (f->op != Audit_equal)
411 return -EINVAL;
412 if (entry->rule.listnr != AUDIT_FILTER_EXIT)
413 return -EINVAL;
414 break;
415 }
416 return 0;
417 }
418
419 /* Translate struct audit_rule_data to kernel's rule representation. */
420 static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
421 size_t datasz)
422 {
423 int err = 0;
424 struct audit_entry *entry;
425 void *bufp;
426 size_t remain = datasz - sizeof(struct audit_rule_data);
427 int i;
428 char *str;
429 struct audit_fsnotify_mark *audit_mark;
430
431 entry = audit_to_entry_common(data);
432 if (IS_ERR(entry))
433 goto exit_nofree;
434
435 bufp = data->buf;
436 for (i = 0; i < data->field_count; i++) {
437 struct audit_field *f = &entry->rule.fields[i];
438
439 err = -EINVAL;
440
441 f->op = audit_to_op(data->fieldflags[i]);
442 if (f->op == Audit_bad)
443 goto exit_free;
444
445 f->type = data->fields[i];
446 f->val = data->values[i];
447
448 /* Support legacy tests for a valid loginuid */
449 if ((f->type == AUDIT_LOGINUID) && (f->val == AUDIT_UID_UNSET)) {
450 f->type = AUDIT_LOGINUID_SET;
451 f->val = 0;
452 entry->rule.pflags |= AUDIT_LOGINUID_LEGACY;
453 }
454
455 err = audit_field_valid(entry, f);
456 if (err)
457 goto exit_free;
458
459 err = -EINVAL;
460 switch (f->type) {
461 case AUDIT_LOGINUID:
462 case AUDIT_UID:
463 case AUDIT_EUID:
464 case AUDIT_SUID:
465 case AUDIT_FSUID:
466 case AUDIT_OBJ_UID:
467 f->uid = make_kuid(current_user_ns(), f->val);
468 if (!uid_valid(f->uid))
469 goto exit_free;
470 break;
471 case AUDIT_GID:
472 case AUDIT_EGID:
473 case AUDIT_SGID:
474 case AUDIT_FSGID:
475 case AUDIT_OBJ_GID:
476 f->gid = make_kgid(current_user_ns(), f->val);
477 if (!gid_valid(f->gid))
478 goto exit_free;
479 break;
480 case AUDIT_SESSIONID:
481 case AUDIT_ARCH:
482 entry->rule.arch_f = f;
483 break;
484 case AUDIT_SUBJ_USER:
485 case AUDIT_SUBJ_ROLE:
486 case AUDIT_SUBJ_TYPE:
487 case AUDIT_SUBJ_SEN:
488 case AUDIT_SUBJ_CLR:
489 case AUDIT_OBJ_USER:
490 case AUDIT_OBJ_ROLE:
491 case AUDIT_OBJ_TYPE:
492 case AUDIT_OBJ_LEV_LOW:
493 case AUDIT_OBJ_LEV_HIGH:
494 str = audit_unpack_string(&bufp, &remain, f->val);
495 if (IS_ERR(str))
496 goto exit_free;
497 entry->rule.buflen += f->val;
498
499 err = security_audit_rule_init(f->type, f->op, str,
500 (void **)&f->lsm_rule);
501 /* Keep currently invalid fields around in case they
502 * become valid after a policy reload. */
503 if (err == -EINVAL) {
504 pr_warn("audit rule for LSM \'%s\' is invalid\n",
505 str);
506 err = 0;
507 }
508 if (err) {
509 kfree(str);
510 goto exit_free;
511 } else
512 f->lsm_str = str;
513 break;
514 case AUDIT_WATCH:
515 str = audit_unpack_string(&bufp, &remain, f->val);
516 if (IS_ERR(str))
517 goto exit_free;
518 entry->rule.buflen += f->val;
519
520 err = audit_to_watch(&entry->rule, str, f->val, f->op);
521 if (err) {
522 kfree(str);
523 goto exit_free;
524 }
525 break;
526 case AUDIT_DIR:
527 str = audit_unpack_string(&bufp, &remain, f->val);
528 if (IS_ERR(str))
529 goto exit_free;
530 entry->rule.buflen += f->val;
531
532 err = audit_make_tree(&entry->rule, str, f->op);
533 kfree(str);
534 if (err)
535 goto exit_free;
536 break;
537 case AUDIT_INODE:
538 err = audit_to_inode(&entry->rule, f);
539 if (err)
540 goto exit_free;
541 break;
542 case AUDIT_FILTERKEY:
543 if (entry->rule.filterkey || f->val > AUDIT_MAX_KEY_LEN)
544 goto exit_free;
545 str = audit_unpack_string(&bufp, &remain, f->val);
546 if (IS_ERR(str))
547 goto exit_free;
548 entry->rule.buflen += f->val;
549 entry->rule.filterkey = str;
550 break;
551 case AUDIT_EXE:
552 if (entry->rule.exe || f->val > PATH_MAX)
553 goto exit_free;
554 str = audit_unpack_string(&bufp, &remain, f->val);
555 if (IS_ERR(str)) {
556 err = PTR_ERR(str);
557 goto exit_free;
558 }
559 entry->rule.buflen += f->val;
560
561 audit_mark = audit_alloc_mark(&entry->rule, str, f->val);
562 if (IS_ERR(audit_mark)) {
563 kfree(str);
564 err = PTR_ERR(audit_mark);
565 goto exit_free;
566 }
567 entry->rule.exe = audit_mark;
568 break;
569 }
570 }
571
572 if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal)
573 entry->rule.inode_f = NULL;
574
575 exit_nofree:
576 return entry;
577
578 exit_free:
579 if (entry->rule.tree)
580 audit_put_tree(entry->rule.tree); /* that's the temporary one */
581 if (entry->rule.exe)
582 audit_remove_mark(entry->rule.exe); /* that's the template one */
583 audit_free_rule(entry);
584 return ERR_PTR(err);
585 }
586
587 /* Pack a filter field's string representation into data block. */
588 static inline size_t audit_pack_string(void **bufp, const char *str)
589 {
590 size_t len = strlen(str);
591
592 memcpy(*bufp, str, len);
593 *bufp += len;
594
595 return len;
596 }
597
598 /* Translate kernel rule representation to struct audit_rule_data. */
599 static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule)
600 {
601 struct audit_rule_data *data;
602 void *bufp;
603 int i;
604
605 data = kmalloc(sizeof(*data) + krule->buflen, GFP_KERNEL);
606 if (unlikely(!data))
607 return NULL;
608 memset(data, 0, sizeof(*data));
609
610 data->flags = krule->flags | krule->listnr;
611 data->action = krule->action;
612 data->field_count = krule->field_count;
613 bufp = data->buf;
614 for (i = 0; i < data->field_count; i++) {
615 struct audit_field *f = &krule->fields[i];
616
617 data->fields[i] = f->type;
618 data->fieldflags[i] = audit_ops[f->op];
619 switch(f->type) {
620 case AUDIT_SUBJ_USER:
621 case AUDIT_SUBJ_ROLE:
622 case AUDIT_SUBJ_TYPE:
623 case AUDIT_SUBJ_SEN:
624 case AUDIT_SUBJ_CLR:
625 case AUDIT_OBJ_USER:
626 case AUDIT_OBJ_ROLE:
627 case AUDIT_OBJ_TYPE:
628 case AUDIT_OBJ_LEV_LOW:
629 case AUDIT_OBJ_LEV_HIGH:
630 data->buflen += data->values[i] =
631 audit_pack_string(&bufp, f->lsm_str);
632 break;
633 case AUDIT_WATCH:
634 data->buflen += data->values[i] =
635 audit_pack_string(&bufp,
636 audit_watch_path(krule->watch));
637 break;
638 case AUDIT_DIR:
639 data->buflen += data->values[i] =
640 audit_pack_string(&bufp,
641 audit_tree_path(krule->tree));
642 break;
643 case AUDIT_FILTERKEY:
644 data->buflen += data->values[i] =
645 audit_pack_string(&bufp, krule->filterkey);
646 break;
647 case AUDIT_EXE:
648 data->buflen += data->values[i] =
649 audit_pack_string(&bufp, audit_mark_path(krule->exe));
650 break;
651 case AUDIT_LOGINUID_SET:
652 if (krule->pflags & AUDIT_LOGINUID_LEGACY && !f->val) {
653 data->fields[i] = AUDIT_LOGINUID;
654 data->values[i] = AUDIT_UID_UNSET;
655 break;
656 }
657 /* fallthrough if set */
658 default:
659 data->values[i] = f->val;
660 }
661 }
662 for (i = 0; i < AUDIT_BITMASK_SIZE; i++) data->mask[i] = krule->mask[i];
663
664 return data;
665 }
666
667 /* Compare two rules in kernel format. Considered success if rules
668 * don't match. */
669 static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
670 {
671 int i;
672
673 if (a->flags != b->flags ||
674 a->pflags != b->pflags ||
675 a->listnr != b->listnr ||
676 a->action != b->action ||
677 a->field_count != b->field_count)
678 return 1;
679
680 for (i = 0; i < a->field_count; i++) {
681 if (a->fields[i].type != b->fields[i].type ||
682 a->fields[i].op != b->fields[i].op)
683 return 1;
684
685 switch(a->fields[i].type) {
686 case AUDIT_SUBJ_USER:
687 case AUDIT_SUBJ_ROLE:
688 case AUDIT_SUBJ_TYPE:
689 case AUDIT_SUBJ_SEN:
690 case AUDIT_SUBJ_CLR:
691 case AUDIT_OBJ_USER:
692 case AUDIT_OBJ_ROLE:
693 case AUDIT_OBJ_TYPE:
694 case AUDIT_OBJ_LEV_LOW:
695 case AUDIT_OBJ_LEV_HIGH:
696 if (strcmp(a->fields[i].lsm_str, b->fields[i].lsm_str))
697 return 1;
698 break;
699 case AUDIT_WATCH:
700 if (strcmp(audit_watch_path(a->watch),
701 audit_watch_path(b->watch)))
702 return 1;
703 break;
704 case AUDIT_DIR:
705 if (strcmp(audit_tree_path(a->tree),
706 audit_tree_path(b->tree)))
707 return 1;
708 break;
709 case AUDIT_FILTERKEY:
710 /* both filterkeys exist based on above type compare */
711 if (strcmp(a->filterkey, b->filterkey))
712 return 1;
713 break;
714 case AUDIT_EXE:
715 /* both paths exist based on above type compare */
716 if (strcmp(audit_mark_path(a->exe),
717 audit_mark_path(b->exe)))
718 return 1;
719 break;
720 case AUDIT_UID:
721 case AUDIT_EUID:
722 case AUDIT_SUID:
723 case AUDIT_FSUID:
724 case AUDIT_LOGINUID:
725 case AUDIT_OBJ_UID:
726 if (!uid_eq(a->fields[i].uid, b->fields[i].uid))
727 return 1;
728 break;
729 case AUDIT_GID:
730 case AUDIT_EGID:
731 case AUDIT_SGID:
732 case AUDIT_FSGID:
733 case AUDIT_OBJ_GID:
734 if (!gid_eq(a->fields[i].gid, b->fields[i].gid))
735 return 1;
736 break;
737 default:
738 if (a->fields[i].val != b->fields[i].val)
739 return 1;
740 }
741 }
742
743 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
744 if (a->mask[i] != b->mask[i])
745 return 1;
746
747 return 0;
748 }
749
750 /* Duplicate LSM field information. The lsm_rule is opaque, so must be
751 * re-initialized. */
752 static inline int audit_dupe_lsm_field(struct audit_field *df,
753 struct audit_field *sf)
754 {
755 int ret = 0;
756 char *lsm_str;
757
758 /* our own copy of lsm_str */
759 lsm_str = kstrdup(sf->lsm_str, GFP_KERNEL);
760 if (unlikely(!lsm_str))
761 return -ENOMEM;
762 df->lsm_str = lsm_str;
763
764 /* our own (refreshed) copy of lsm_rule */
765 ret = security_audit_rule_init(df->type, df->op, df->lsm_str,
766 (void **)&df->lsm_rule);
767 /* Keep currently invalid fields around in case they
768 * become valid after a policy reload. */
769 if (ret == -EINVAL) {
770 pr_warn("audit rule for LSM \'%s\' is invalid\n",
771 df->lsm_str);
772 ret = 0;
773 }
774
775 return ret;
776 }
777
778 /* Duplicate an audit rule. This will be a deep copy with the exception
779 * of the watch - that pointer is carried over. The LSM specific fields
780 * will be updated in the copy. The point is to be able to replace the old
781 * rule with the new rule in the filterlist, then free the old rule.
782 * The rlist element is undefined; list manipulations are handled apart from
783 * the initial copy. */
784 struct audit_entry *audit_dupe_rule(struct audit_krule *old)
785 {
786 u32 fcount = old->field_count;
787 struct audit_entry *entry;
788 struct audit_krule *new;
789 char *fk;
790 int i, err = 0;
791
792 entry = audit_init_entry(fcount);
793 if (unlikely(!entry))
794 return ERR_PTR(-ENOMEM);
795
796 new = &entry->rule;
797 new->flags = old->flags;
798 new->pflags = old->pflags;
799 new->listnr = old->listnr;
800 new->action = old->action;
801 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
802 new->mask[i] = old->mask[i];
803 new->prio = old->prio;
804 new->buflen = old->buflen;
805 new->inode_f = old->inode_f;
806 new->field_count = old->field_count;
807
808 /*
809 * note that we are OK with not refcounting here; audit_match_tree()
810 * never dereferences tree and we can't get false positives there
811 * since we'd have to have rule gone from the list *and* removed
812 * before the chunks found by lookup had been allocated, i.e. before
813 * the beginning of list scan.
814 */
815 new->tree = old->tree;
816 memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount);
817
818 /* deep copy this information, updating the lsm_rule fields, because
819 * the originals will all be freed when the old rule is freed. */
820 for (i = 0; i < fcount; i++) {
821 switch (new->fields[i].type) {
822 case AUDIT_SUBJ_USER:
823 case AUDIT_SUBJ_ROLE:
824 case AUDIT_SUBJ_TYPE:
825 case AUDIT_SUBJ_SEN:
826 case AUDIT_SUBJ_CLR:
827 case AUDIT_OBJ_USER:
828 case AUDIT_OBJ_ROLE:
829 case AUDIT_OBJ_TYPE:
830 case AUDIT_OBJ_LEV_LOW:
831 case AUDIT_OBJ_LEV_HIGH:
832 err = audit_dupe_lsm_field(&new->fields[i],
833 &old->fields[i]);
834 break;
835 case AUDIT_FILTERKEY:
836 fk = kstrdup(old->filterkey, GFP_KERNEL);
837 if (unlikely(!fk))
838 err = -ENOMEM;
839 else
840 new->filterkey = fk;
841 break;
842 case AUDIT_EXE:
843 err = audit_dupe_exe(new, old);
844 break;
845 }
846 if (err) {
847 if (new->exe)
848 audit_remove_mark(new->exe);
849 audit_free_rule(entry);
850 return ERR_PTR(err);
851 }
852 }
853
854 if (old->watch) {
855 audit_get_watch(old->watch);
856 new->watch = old->watch;
857 }
858
859 return entry;
860 }
861
862 /* Find an existing audit rule.
863 * Caller must hold audit_filter_mutex to prevent stale rule data. */
864 static struct audit_entry *audit_find_rule(struct audit_entry *entry,
865 struct list_head **p)
866 {
867 struct audit_entry *e, *found = NULL;
868 struct list_head *list;
869 int h;
870
871 if (entry->rule.inode_f) {
872 h = audit_hash_ino(entry->rule.inode_f->val);
873 *p = list = &audit_inode_hash[h];
874 } else if (entry->rule.watch) {
875 /* we don't know the inode number, so must walk entire hash */
876 for (h = 0; h < AUDIT_INODE_BUCKETS; h++) {
877 list = &audit_inode_hash[h];
878 list_for_each_entry(e, list, list)
879 if (!audit_compare_rule(&entry->rule, &e->rule)) {
880 found = e;
881 goto out;
882 }
883 }
884 goto out;
885 } else {
886 *p = list = &audit_filter_list[entry->rule.listnr];
887 }
888
889 list_for_each_entry(e, list, list)
890 if (!audit_compare_rule(&entry->rule, &e->rule)) {
891 found = e;
892 goto out;
893 }
894
895 out:
896 return found;
897 }
898
899 static u64 prio_low = ~0ULL/2;
900 static u64 prio_high = ~0ULL/2 - 1;
901
902 /* Add rule to given filterlist if not a duplicate. */
903 static inline int audit_add_rule(struct audit_entry *entry)
904 {
905 struct audit_entry *e;
906 struct audit_watch *watch = entry->rule.watch;
907 struct audit_tree *tree = entry->rule.tree;
908 struct list_head *list;
909 int err = 0;
910 #ifdef CONFIG_AUDITSYSCALL
911 int dont_count = 0;
912
913 /* If either of these, don't count towards total */
914 if (entry->rule.listnr == AUDIT_FILTER_USER ||
915 entry->rule.listnr == AUDIT_FILTER_TYPE)
916 dont_count = 1;
917 #endif
918
919 mutex_lock(&audit_filter_mutex);
920 e = audit_find_rule(entry, &list);
921 if (e) {
922 mutex_unlock(&audit_filter_mutex);
923 err = -EEXIST;
924 /* normally audit_add_tree_rule() will free it on failure */
925 if (tree)
926 audit_put_tree(tree);
927 return err;
928 }
929
930 if (watch) {
931 /* audit_filter_mutex is dropped and re-taken during this call */
932 err = audit_add_watch(&entry->rule, &list);
933 if (err) {
934 mutex_unlock(&audit_filter_mutex);
935 /*
936 * normally audit_add_tree_rule() will free it
937 * on failure
938 */
939 if (tree)
940 audit_put_tree(tree);
941 return err;
942 }
943 }
944 if (tree) {
945 err = audit_add_tree_rule(&entry->rule);
946 if (err) {
947 mutex_unlock(&audit_filter_mutex);
948 return err;
949 }
950 }
951
952 entry->rule.prio = ~0ULL;
953 if (entry->rule.listnr == AUDIT_FILTER_EXIT) {
954 if (entry->rule.flags & AUDIT_FILTER_PREPEND)
955 entry->rule.prio = ++prio_high;
956 else
957 entry->rule.prio = --prio_low;
958 }
959
960 if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
961 list_add(&entry->rule.list,
962 &audit_rules_list[entry->rule.listnr]);
963 list_add_rcu(&entry->list, list);
964 entry->rule.flags &= ~AUDIT_FILTER_PREPEND;
965 } else {
966 list_add_tail(&entry->rule.list,
967 &audit_rules_list[entry->rule.listnr]);
968 list_add_tail_rcu(&entry->list, list);
969 }
970 #ifdef CONFIG_AUDITSYSCALL
971 if (!dont_count)
972 audit_n_rules++;
973
974 if (!audit_match_signal(entry))
975 audit_signals++;
976 #endif
977 mutex_unlock(&audit_filter_mutex);
978
979 return err;
980 }
981
982 /* Remove an existing rule from filterlist. */
983 int audit_del_rule(struct audit_entry *entry)
984 {
985 struct audit_entry *e;
986 struct audit_tree *tree = entry->rule.tree;
987 struct list_head *list;
988 int ret = 0;
989 #ifdef CONFIG_AUDITSYSCALL
990 int dont_count = 0;
991
992 /* If either of these, don't count towards total */
993 if (entry->rule.listnr == AUDIT_FILTER_USER ||
994 entry->rule.listnr == AUDIT_FILTER_TYPE)
995 dont_count = 1;
996 #endif
997
998 mutex_lock(&audit_filter_mutex);
999 e = audit_find_rule(entry, &list);
1000 if (!e) {
1001 ret = -ENOENT;
1002 goto out;
1003 }
1004
1005 if (e->rule.watch)
1006 audit_remove_watch_rule(&e->rule);
1007
1008 if (e->rule.tree)
1009 audit_remove_tree_rule(&e->rule);
1010
1011 if (e->rule.exe)
1012 audit_remove_mark_rule(&e->rule);
1013
1014 #ifdef CONFIG_AUDITSYSCALL
1015 if (!dont_count)
1016 audit_n_rules--;
1017
1018 if (!audit_match_signal(entry))
1019 audit_signals--;
1020 #endif
1021
1022 list_del_rcu(&e->list);
1023 list_del(&e->rule.list);
1024 call_rcu(&e->rcu, audit_free_rule_rcu);
1025
1026 out:
1027 mutex_unlock(&audit_filter_mutex);
1028
1029 if (tree)
1030 audit_put_tree(tree); /* that's the temporary one */
1031
1032 return ret;
1033 }
1034
1035 /* List rules using struct audit_rule_data. */
1036 static void audit_list_rules(int seq, struct sk_buff_head *q)
1037 {
1038 struct sk_buff *skb;
1039 struct audit_krule *r;
1040 int i;
1041
1042 /* This is a blocking read, so use audit_filter_mutex instead of rcu
1043 * iterator to sync with list writers. */
1044 for (i=0; i<AUDIT_NR_FILTERS; i++) {
1045 list_for_each_entry(r, &audit_rules_list[i], list) {
1046 struct audit_rule_data *data;
1047
1048 data = audit_krule_to_data(r);
1049 if (unlikely(!data))
1050 break;
1051 skb = audit_make_reply(seq, AUDIT_LIST_RULES, 0, 1,
1052 data,
1053 sizeof(*data) + data->buflen);
1054 if (skb)
1055 skb_queue_tail(q, skb);
1056 kfree(data);
1057 }
1058 }
1059 skb = audit_make_reply(seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);
1060 if (skb)
1061 skb_queue_tail(q, skb);
1062 }
1063
1064 /* Log rule additions and removals */
1065 static void audit_log_rule_change(char *action, struct audit_krule *rule, int res)
1066 {
1067 struct audit_buffer *ab;
1068 uid_t loginuid = from_kuid(&init_user_ns, audit_get_loginuid(current));
1069 unsigned int sessionid = audit_get_sessionid(current);
1070
1071 if (!audit_enabled)
1072 return;
1073
1074 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
1075 if (!ab)
1076 return;
1077 audit_log_format(ab, "auid=%u ses=%u" ,loginuid, sessionid);
1078 audit_log_task_context(ab);
1079 audit_log_format(ab, " op=%s", action);
1080 audit_log_key(ab, rule->filterkey);
1081 audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
1082 audit_log_end(ab);
1083 }
1084
1085 /**
1086 * audit_rule_change - apply all rules to the specified message type
1087 * @type: audit message type
1088 * @seq: netlink audit message sequence (serial) number
1089 * @data: payload data
1090 * @datasz: size of payload data
1091 */
1092 int audit_rule_change(int type, int seq, void *data, size_t datasz)
1093 {
1094 int err = 0;
1095 struct audit_entry *entry;
1096
1097 entry = audit_data_to_entry(data, datasz);
1098 if (IS_ERR(entry))
1099 return PTR_ERR(entry);
1100
1101 switch (type) {
1102 case AUDIT_ADD_RULE:
1103 err = audit_add_rule(entry);
1104 audit_log_rule_change("add_rule", &entry->rule, !err);
1105 break;
1106 case AUDIT_DEL_RULE:
1107 err = audit_del_rule(entry);
1108 audit_log_rule_change("remove_rule", &entry->rule, !err);
1109 break;
1110 default:
1111 err = -EINVAL;
1112 WARN_ON(1);
1113 }
1114
1115 if (err || type == AUDIT_DEL_RULE) {
1116 if (entry->rule.exe)
1117 audit_remove_mark(entry->rule.exe);
1118 audit_free_rule(entry);
1119 }
1120
1121 return err;
1122 }
1123
1124 /**
1125 * audit_list_rules_send - list the audit rules
1126 * @request_skb: skb of request we are replying to (used to target the reply)
1127 * @seq: netlink audit message sequence (serial) number
1128 */
1129 int audit_list_rules_send(struct sk_buff *request_skb, int seq)
1130 {
1131 u32 portid = NETLINK_CB(request_skb).portid;
1132 struct net *net = sock_net(NETLINK_CB(request_skb).sk);
1133 struct task_struct *tsk;
1134 struct audit_netlink_list *dest;
1135 int err = 0;
1136
1137 /* We can't just spew out the rules here because we might fill
1138 * the available socket buffer space and deadlock waiting for
1139 * auditctl to read from it... which isn't ever going to
1140 * happen if we're actually running in the context of auditctl
1141 * trying to _send_ the stuff */
1142
1143 dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL);
1144 if (!dest)
1145 return -ENOMEM;
1146 dest->net = get_net(net);
1147 dest->portid = portid;
1148 skb_queue_head_init(&dest->q);
1149
1150 mutex_lock(&audit_filter_mutex);
1151 audit_list_rules(seq, &dest->q);
1152 mutex_unlock(&audit_filter_mutex);
1153
1154 tsk = kthread_run(audit_send_list, dest, "audit_send_list");
1155 if (IS_ERR(tsk)) {
1156 skb_queue_purge(&dest->q);
1157 kfree(dest);
1158 err = PTR_ERR(tsk);
1159 }
1160
1161 return err;
1162 }
1163
1164 int audit_comparator(u32 left, u32 op, u32 right)
1165 {
1166 switch (op) {
1167 case Audit_equal:
1168 return (left == right);
1169 case Audit_not_equal:
1170 return (left != right);
1171 case Audit_lt:
1172 return (left < right);
1173 case Audit_le:
1174 return (left <= right);
1175 case Audit_gt:
1176 return (left > right);
1177 case Audit_ge:
1178 return (left >= right);
1179 case Audit_bitmask:
1180 return (left & right);
1181 case Audit_bittest:
1182 return ((left & right) == right);
1183 default:
1184 BUG();
1185 return 0;
1186 }
1187 }
1188
1189 int audit_uid_comparator(kuid_t left, u32 op, kuid_t right)
1190 {
1191 switch (op) {
1192 case Audit_equal:
1193 return uid_eq(left, right);
1194 case Audit_not_equal:
1195 return !uid_eq(left, right);
1196 case Audit_lt:
1197 return uid_lt(left, right);
1198 case Audit_le:
1199 return uid_lte(left, right);
1200 case Audit_gt:
1201 return uid_gt(left, right);
1202 case Audit_ge:
1203 return uid_gte(left, right);
1204 case Audit_bitmask:
1205 case Audit_bittest:
1206 default:
1207 BUG();
1208 return 0;
1209 }
1210 }
1211
1212 int audit_gid_comparator(kgid_t left, u32 op, kgid_t right)
1213 {
1214 switch (op) {
1215 case Audit_equal:
1216 return gid_eq(left, right);
1217 case Audit_not_equal:
1218 return !gid_eq(left, right);
1219 case Audit_lt:
1220 return gid_lt(left, right);
1221 case Audit_le:
1222 return gid_lte(left, right);
1223 case Audit_gt:
1224 return gid_gt(left, right);
1225 case Audit_ge:
1226 return gid_gte(left, right);
1227 case Audit_bitmask:
1228 case Audit_bittest:
1229 default:
1230 BUG();
1231 return 0;
1232 }
1233 }
1234
1235 /**
1236 * parent_len - find the length of the parent portion of a pathname
1237 * @path: pathname of which to determine length
1238 */
1239 int parent_len(const char *path)
1240 {
1241 int plen;
1242 const char *p;
1243
1244 plen = strlen(path);
1245
1246 if (plen == 0)
1247 return plen;
1248
1249 /* disregard trailing slashes */
1250 p = path + plen - 1;
1251 while ((*p == '/') && (p > path))
1252 p--;
1253
1254 /* walk backward until we find the next slash or hit beginning */
1255 while ((*p != '/') && (p > path))
1256 p--;
1257
1258 /* did we find a slash? Then increment to include it in path */
1259 if (*p == '/')
1260 p++;
1261
1262 return p - path;
1263 }
1264
1265 /**
1266 * audit_compare_dname_path - compare given dentry name with last component in
1267 * given path. Return of 0 indicates a match.
1268 * @dname: dentry name that we're comparing
1269 * @path: full pathname that we're comparing
1270 * @parentlen: length of the parent if known. Passing in AUDIT_NAME_FULL
1271 * here indicates that we must compute this value.
1272 */
1273 int audit_compare_dname_path(const char *dname, const char *path, int parentlen)
1274 {
1275 int dlen, pathlen;
1276 const char *p;
1277
1278 dlen = strlen(dname);
1279 pathlen = strlen(path);
1280 if (pathlen < dlen)
1281 return 1;
1282
1283 parentlen = parentlen == AUDIT_NAME_FULL ? parent_len(path) : parentlen;
1284 if (pathlen - parentlen != dlen)
1285 return 1;
1286
1287 p = path + parentlen;
1288
1289 return strncmp(p, dname, dlen);
1290 }
1291
1292 int audit_filter(int msgtype, unsigned int listtype)
1293 {
1294 struct audit_entry *e;
1295 int ret = 1; /* Audit by default */
1296
1297 rcu_read_lock();
1298 if (list_empty(&audit_filter_list[listtype]))
1299 goto unlock_and_return;
1300 list_for_each_entry_rcu(e, &audit_filter_list[listtype], list) {
1301 int i, result = 0;
1302
1303 for (i = 0; i < e->rule.field_count; i++) {
1304 struct audit_field *f = &e->rule.fields[i];
1305 pid_t pid;
1306 u32 sid;
1307
1308 switch (f->type) {
1309 case AUDIT_PID:
1310 pid = task_pid_nr(current);
1311 result = audit_comparator(pid, f->op, f->val);
1312 break;
1313 case AUDIT_UID:
1314 result = audit_uid_comparator(current_uid(), f->op, f->uid);
1315 break;
1316 case AUDIT_GID:
1317 result = audit_gid_comparator(current_gid(), f->op, f->gid);
1318 break;
1319 case AUDIT_LOGINUID:
1320 result = audit_uid_comparator(audit_get_loginuid(current),
1321 f->op, f->uid);
1322 break;
1323 case AUDIT_LOGINUID_SET:
1324 result = audit_comparator(audit_loginuid_set(current),
1325 f->op, f->val);
1326 break;
1327 case AUDIT_MSGTYPE:
1328 result = audit_comparator(msgtype, f->op, f->val);
1329 break;
1330 case AUDIT_SUBJ_USER:
1331 case AUDIT_SUBJ_ROLE:
1332 case AUDIT_SUBJ_TYPE:
1333 case AUDIT_SUBJ_SEN:
1334 case AUDIT_SUBJ_CLR:
1335 if (f->lsm_rule) {
1336 security_task_getsecid(current, &sid);
1337 result = security_audit_rule_match(sid,
1338 f->type, f->op, f->lsm_rule, NULL);
1339 }
1340 break;
1341 default:
1342 goto unlock_and_return;
1343 }
1344 if (result < 0) /* error */
1345 goto unlock_and_return;
1346 if (!result)
1347 break;
1348 }
1349 if (result > 0) {
1350 if (e->rule.action == AUDIT_NEVER || listtype == AUDIT_FILTER_TYPE)
1351 ret = 0;
1352 break;
1353 }
1354 }
1355 unlock_and_return:
1356 rcu_read_unlock();
1357 return ret;
1358 }
1359
1360 static 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 (entry->rule.exe)
1371 audit_remove_mark(entry->rule.exe);
1372 if (IS_ERR(nentry)) {
1373 /* save the first error encountered for the
1374 * return value */
1375 err = PTR_ERR(nentry);
1376 audit_panic("error updating LSM filters");
1377 if (r->watch)
1378 list_del(&r->rlist);
1379 list_del_rcu(&entry->list);
1380 list_del(&r->list);
1381 } else {
1382 if (r->watch || r->tree)
1383 list_replace_init(&r->rlist, &nentry->rule.rlist);
1384 list_replace_rcu(&entry->list, &nentry->list);
1385 list_replace(&r->list, &nentry->rule.list);
1386 }
1387 call_rcu(&entry->rcu, audit_free_rule_rcu);
1388
1389 return err;
1390 }
1391
1392 /* This function will re-initialize the lsm_rule field of all applicable rules.
1393 * It will traverse the filter lists serarching for rules that contain LSM
1394 * specific filter fields. When such a rule is found, it is copied, the
1395 * LSM field is re-initialized, and the old rule is replaced with the
1396 * updated rule. */
1397 int audit_update_lsm_rules(void)
1398 {
1399 struct audit_krule *r, *n;
1400 int i, err = 0;
1401
1402 /* audit_filter_mutex synchronizes the writers */
1403 mutex_lock(&audit_filter_mutex);
1404
1405 for (i = 0; i < AUDIT_NR_FILTERS; i++) {
1406 list_for_each_entry_safe(r, n, &audit_rules_list[i], list) {
1407 int res = update_lsm_rule(r);
1408 if (!err)
1409 err = res;
1410 }
1411 }
1412 mutex_unlock(&audit_filter_mutex);
1413
1414 return err;
1415 }
Linux with added FPC-III support