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net: cpsw: catch of_get_phy_mode failing and propagate error
[linux/fpc-iii.git] / kernel / auditfilter.c
blob14a78cca384edb9cf8f36dc3f7fb5340c267c623
1 /* auditfilter.c -- filtering of audit events
2 *
3 * Copyright 2003-2004 Red Hat, Inc.
4 * Copyright 2005 Hewlett-Packard Development Company, L.P.
5 * Copyright 2005 IBM Corporation
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 */
21
22 #include <linux/kernel.h>
23 #include <linux/audit.h>
24 #include <linux/kthread.h>
25 #include <linux/mutex.h>
26 #include <linux/fs.h>
27 #include <linux/namei.h>
28 #include <linux/netlink.h>
29 #include <linux/sched.h>
30 #include <linux/slab.h>
31 #include <linux/security.h>
32 #include "audit.h"
33
34 /*
35 * Locking model:
36 *
37 * audit_filter_mutex:
38 * Synchronizes writes and blocking reads of audit's filterlist
39 * data. Rcu is used to traverse the filterlist and access
40 * contents of structs audit_entry, audit_watch and opaque
41 * LSM rules during filtering. If modified, these structures
42 * must be copied and replace their counterparts in the filterlist.
43 * An audit_parent struct is not accessed during filtering, so may
44 * be written directly provided audit_filter_mutex is held.
45 */
46
47 /* Audit filter lists, defined in <linux/audit.h> */
48 struct list_head audit_filter_list[AUDIT_NR_FILTERS] = {
49 LIST_HEAD_INIT(audit_filter_list[0]),
50 LIST_HEAD_INIT(audit_filter_list[1]),
51 LIST_HEAD_INIT(audit_filter_list[2]),
52 LIST_HEAD_INIT(audit_filter_list[3]),
53 LIST_HEAD_INIT(audit_filter_list[4]),
54 LIST_HEAD_INIT(audit_filter_list[5]),
55 #if AUDIT_NR_FILTERS != 6
56 #error Fix audit_filter_list initialiser
57 #endif
58 };
59 static struct list_head audit_rules_list[AUDIT_NR_FILTERS] = {
60 LIST_HEAD_INIT(audit_rules_list[0]),
61 LIST_HEAD_INIT(audit_rules_list[1]),
62 LIST_HEAD_INIT(audit_rules_list[2]),
63 LIST_HEAD_INIT(audit_rules_list[3]),
64 LIST_HEAD_INIT(audit_rules_list[4]),
65 LIST_HEAD_INIT(audit_rules_list[5]),
66 };
67
68 DEFINE_MUTEX(audit_filter_mutex);
69
70 static inline void audit_free_rule(struct audit_entry *e)
71 {
72 int i;
73 struct audit_krule *erule = &e->rule;
74
75 /* some rules don't have associated watches */
76 if (erule->watch)
77 audit_put_watch(erule->watch);
78 if (erule->fields)
79 for (i = 0; i < erule->field_count; i++) {
80 struct audit_field *f = &erule->fields[i];
81 kfree(f->lsm_str);
82 security_audit_rule_free(f->lsm_rule);
83 }
84 kfree(erule->fields);
85 kfree(erule->filterkey);
86 kfree(e);
87 }
88
89 void audit_free_rule_rcu(struct rcu_head *head)
90 {
91 struct audit_entry *e = container_of(head, struct audit_entry, rcu);
92 audit_free_rule(e);
93 }
94
95 /* Initialize an audit filterlist entry. */
96 static inline struct audit_entry *audit_init_entry(u32 field_count)
97 {
98 struct audit_entry *entry;
99 struct audit_field *fields;
100
101 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
102 if (unlikely(!entry))
103 return NULL;
104
105 fields = kzalloc(sizeof(*fields) * field_count, GFP_KERNEL);
106 if (unlikely(!fields)) {
107 kfree(entry);
108 return NULL;
109 }
110 entry->rule.fields = fields;
111
112 return entry;
113 }
114
115 /* Unpack a filter field's string representation from user-space
116 * buffer. */
117 char *audit_unpack_string(void **bufp, size_t *remain, size_t len)
118 {
119 char *str;
120
121 if (!*bufp || (len == 0) || (len > *remain))
122 return ERR_PTR(-EINVAL);
123
124 /* Of the currently implemented string fields, PATH_MAX
125 * defines the longest valid length.
126 */
127 if (len > PATH_MAX)
128 return ERR_PTR(-ENAMETOOLONG);
129
130 str = kmalloc(len + 1, GFP_KERNEL);
131 if (unlikely(!str))
132 return ERR_PTR(-ENOMEM);
133
134 memcpy(str, *bufp, len);
135 str[len] = 0;
136 *bufp += len;
137 *remain -= len;
138
139 return str;
140 }
141
142 /* Translate an inode field to kernel respresentation. */
143 static inline int audit_to_inode(struct audit_krule *krule,
144 struct audit_field *f)
145 {
146 if (krule->listnr != AUDIT_FILTER_EXIT ||
147 krule->watch || krule->inode_f || krule->tree ||
148 (f->op != Audit_equal && f->op != Audit_not_equal))
149 return -EINVAL;
150
151 krule->inode_f = f;
152 return 0;
153 }
154
155 static __u32 *classes[AUDIT_SYSCALL_CLASSES];
156
157 int __init audit_register_class(int class, unsigned *list)
158 {
159 __u32 *p = kzalloc(AUDIT_BITMASK_SIZE * sizeof(__u32), GFP_KERNEL);
160 if (!p)
161 return -ENOMEM;
162 while (*list != ~0U) {
163 unsigned n = *list++;
164 if (n >= AUDIT_BITMASK_SIZE * 32 - AUDIT_SYSCALL_CLASSES) {
165 kfree(p);
166 return -EINVAL;
167 }
168 p[AUDIT_WORD(n)] |= AUDIT_BIT(n);
169 }
170 if (class >= AUDIT_SYSCALL_CLASSES || classes[class]) {
171 kfree(p);
172 return -EINVAL;
173 }
174 classes[class] = p;
175 return 0;
176 }
177
178 int audit_match_class(int class, unsigned syscall)
179 {
180 if (unlikely(syscall >= AUDIT_BITMASK_SIZE * 32))
181 return 0;
182 if (unlikely(class >= AUDIT_SYSCALL_CLASSES || !classes[class]))
183 return 0;
184 return classes[class][AUDIT_WORD(syscall)] & AUDIT_BIT(syscall);
185 }
186
187 #ifdef CONFIG_AUDITSYSCALL
188 static inline int audit_match_class_bits(int class, u32 *mask)
189 {
190 int i;
191
192 if (classes[class]) {
193 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
194 if (mask[i] & classes[class][i])
195 return 0;
196 }
197 return 1;
198 }
199
200 static int audit_match_signal(struct audit_entry *entry)
201 {
202 struct audit_field *arch = entry->rule.arch_f;
203
204 if (!arch) {
205 /* When arch is unspecified, we must check both masks on biarch
206 * as syscall number alone is ambiguous. */
207 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
208 entry->rule.mask) &&
209 audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
210 entry->rule.mask));
211 }
212
213 switch(audit_classify_arch(arch->val)) {
214 case 0: /* native */
215 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
216 entry->rule.mask));
217 case 1: /* 32bit on biarch */
218 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
219 entry->rule.mask));
220 default:
221 return 1;
222 }
223 }
224 #endif
225
226 /* Common user-space to kernel rule translation. */
227 static inline struct audit_entry *audit_to_entry_common(struct audit_rule *rule)
228 {
229 unsigned listnr;
230 struct audit_entry *entry;
231 int i, err;
232
233 err = -EINVAL;
234 listnr = rule->flags & ~AUDIT_FILTER_PREPEND;
235 switch(listnr) {
236 default:
237 goto exit_err;
238 #ifdef CONFIG_AUDITSYSCALL
239 case AUDIT_FILTER_ENTRY:
240 if (rule->action == AUDIT_ALWAYS)
241 goto exit_err;
242 case AUDIT_FILTER_EXIT:
243 case AUDIT_FILTER_TASK:
244 #endif
245 case AUDIT_FILTER_USER:
246 case AUDIT_FILTER_TYPE:
247 ;
248 }
249 if (unlikely(rule->action == AUDIT_POSSIBLE)) {
250 printk(KERN_ERR "AUDIT_POSSIBLE is deprecated\n");
251 goto exit_err;
252 }
253 if (rule->action != AUDIT_NEVER && rule->action != AUDIT_ALWAYS)
254 goto exit_err;
255 if (rule->field_count > AUDIT_MAX_FIELDS)
256 goto exit_err;
257
258 err = -ENOMEM;
259 entry = audit_init_entry(rule->field_count);
260 if (!entry)
261 goto exit_err;
262
263 entry->rule.flags = rule->flags & AUDIT_FILTER_PREPEND;
264 entry->rule.listnr = listnr;
265 entry->rule.action = rule->action;
266 entry->rule.field_count = rule->field_count;
267
268 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
269 entry->rule.mask[i] = rule->mask[i];
270
271 for (i = 0; i < AUDIT_SYSCALL_CLASSES; i++) {
272 int bit = AUDIT_BITMASK_SIZE * 32 - i - 1;
273 __u32 *p = &entry->rule.mask[AUDIT_WORD(bit)];
274 __u32 *class;
275
276 if (!(*p & AUDIT_BIT(bit)))
277 continue;
278 *p &= ~AUDIT_BIT(bit);
279 class = classes[i];
280 if (class) {
281 int j;
282 for (j = 0; j < AUDIT_BITMASK_SIZE; j++)
283 entry->rule.mask[j] |= class[j];
284 }
285 }
286
287 return entry;
288
289 exit_err:
290 return ERR_PTR(err);
291 }
292
293 static u32 audit_ops[] =
294 {
295 [Audit_equal] = AUDIT_EQUAL,
296 [Audit_not_equal] = AUDIT_NOT_EQUAL,
297 [Audit_bitmask] = AUDIT_BIT_MASK,
298 [Audit_bittest] = AUDIT_BIT_TEST,
299 [Audit_lt] = AUDIT_LESS_THAN,
300 [Audit_gt] = AUDIT_GREATER_THAN,
301 [Audit_le] = AUDIT_LESS_THAN_OR_EQUAL,
302 [Audit_ge] = AUDIT_GREATER_THAN_OR_EQUAL,
303 };
304
305 static u32 audit_to_op(u32 op)
306 {
307 u32 n;
308 for (n = Audit_equal; n < Audit_bad && audit_ops[n] != op; n++)
309 ;
310 return n;
311 }
312
313 /* check if an audit field is valid */
314 static int audit_field_valid(struct audit_entry *entry, struct audit_field *f)
315 {
316 switch(f->type) {
317 case AUDIT_MSGTYPE:
318 if (entry->rule.listnr != AUDIT_FILTER_TYPE &&
319 entry->rule.listnr != AUDIT_FILTER_USER)
320 return -EINVAL;
321 break;
322 };
323
324 switch(f->type) {
325 default:
326 return -EINVAL;
327 case AUDIT_UID:
328 case AUDIT_EUID:
329 case AUDIT_SUID:
330 case AUDIT_FSUID:
331 case AUDIT_LOGINUID:
332 case AUDIT_OBJ_UID:
333 case AUDIT_GID:
334 case AUDIT_EGID:
335 case AUDIT_SGID:
336 case AUDIT_FSGID:
337 case AUDIT_OBJ_GID:
338 case AUDIT_PID:
339 case AUDIT_PERS:
340 case AUDIT_MSGTYPE:
341 case AUDIT_PPID:
342 case AUDIT_DEVMAJOR:
343 case AUDIT_DEVMINOR:
344 case AUDIT_EXIT:
345 case AUDIT_SUCCESS:
346 case AUDIT_INODE:
347 /* bit ops are only useful on syscall args */
348 if (f->op == Audit_bitmask || f->op == Audit_bittest)
349 return -EINVAL;
350 break;
351 case AUDIT_ARG0:
352 case AUDIT_ARG1:
353 case AUDIT_ARG2:
354 case AUDIT_ARG3:
355 case AUDIT_SUBJ_USER:
356 case AUDIT_SUBJ_ROLE:
357 case AUDIT_SUBJ_TYPE:
358 case AUDIT_SUBJ_SEN:
359 case AUDIT_SUBJ_CLR:
360 case AUDIT_OBJ_USER:
361 case AUDIT_OBJ_ROLE:
362 case AUDIT_OBJ_TYPE:
363 case AUDIT_OBJ_LEV_LOW:
364 case AUDIT_OBJ_LEV_HIGH:
365 case AUDIT_WATCH:
366 case AUDIT_DIR:
367 case AUDIT_FILTERKEY:
368 break;
369 case AUDIT_LOGINUID_SET:
370 if ((f->val != 0) && (f->val != 1))
371 return -EINVAL;
372 /* FALL THROUGH */
373 case AUDIT_ARCH:
374 if (f->op != Audit_not_equal && f->op != Audit_equal)
375 return -EINVAL;
376 break;
377 case AUDIT_PERM:
378 if (f->val & ~15)
379 return -EINVAL;
380 break;
381 case AUDIT_FILETYPE:
382 if (f->val & ~S_IFMT)
383 return -EINVAL;
384 break;
385 case AUDIT_FIELD_COMPARE:
386 if (f->val > AUDIT_MAX_FIELD_COMPARE)
387 return -EINVAL;
388 break;
389 };
390 return 0;
391 }
392
393 /* Translate struct audit_rule_data to kernel's rule respresentation. */
394 static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
395 size_t datasz)
396 {
397 int err = 0;
398 struct audit_entry *entry;
399 void *bufp;
400 size_t remain = datasz - sizeof(struct audit_rule_data);
401 int i;
402 char *str;
403
404 entry = audit_to_entry_common((struct audit_rule *)data);
405 if (IS_ERR(entry))
406 goto exit_nofree;
407
408 bufp = data->buf;
409 entry->rule.vers_ops = 2;
410 for (i = 0; i < data->field_count; i++) {
411 struct audit_field *f = &entry->rule.fields[i];
412
413 err = -EINVAL;
414
415 f->op = audit_to_op(data->fieldflags[i]);
416 if (f->op == Audit_bad)
417 goto exit_free;
418
419 f->type = data->fields[i];
420 f->val = data->values[i];
421 f->uid = INVALID_UID;
422 f->gid = INVALID_GID;
423 f->lsm_str = NULL;
424 f->lsm_rule = NULL;
425
426 /* Support legacy tests for a valid loginuid */
427 if ((f->type == AUDIT_LOGINUID) && (f->val == AUDIT_UID_UNSET)) {
428 f->type = AUDIT_LOGINUID_SET;
429 f->val = 0;
430 }
431
432 err = audit_field_valid(entry, f);
433 if (err)
434 goto exit_free;
435
436 err = -EINVAL;
437 switch (f->type) {
438 case AUDIT_LOGINUID:
439 case AUDIT_UID:
440 case AUDIT_EUID:
441 case AUDIT_SUID:
442 case AUDIT_FSUID:
443 case AUDIT_OBJ_UID:
444 f->uid = make_kuid(current_user_ns(), f->val);
445 if (!uid_valid(f->uid))
446 goto exit_free;
447 break;
448 case AUDIT_GID:
449 case AUDIT_EGID:
450 case AUDIT_SGID:
451 case AUDIT_FSGID:
452 case AUDIT_OBJ_GID:
453 f->gid = make_kgid(current_user_ns(), f->val);
454 if (!gid_valid(f->gid))
455 goto exit_free;
456 break;
457 case AUDIT_ARCH:
458 entry->rule.arch_f = f;
459 break;
460 case AUDIT_SUBJ_USER:
461 case AUDIT_SUBJ_ROLE:
462 case AUDIT_SUBJ_TYPE:
463 case AUDIT_SUBJ_SEN:
464 case AUDIT_SUBJ_CLR:
465 case AUDIT_OBJ_USER:
466 case AUDIT_OBJ_ROLE:
467 case AUDIT_OBJ_TYPE:
468 case AUDIT_OBJ_LEV_LOW:
469 case AUDIT_OBJ_LEV_HIGH:
470 str = audit_unpack_string(&bufp, &remain, f->val);
471 if (IS_ERR(str))
472 goto exit_free;
473 entry->rule.buflen += f->val;
474
475 err = security_audit_rule_init(f->type, f->op, str,
476 (void **)&f->lsm_rule);
477 /* Keep currently invalid fields around in case they
478 * become valid after a policy reload. */
479 if (err == -EINVAL) {
480 printk(KERN_WARNING "audit rule for LSM "
481 "\'%s\' is invalid\n", str);
482 err = 0;
483 }
484 if (err) {
485 kfree(str);
486 goto exit_free;
487 } else
488 f->lsm_str = str;
489 break;
490 case AUDIT_WATCH:
491 str = audit_unpack_string(&bufp, &remain, f->val);
492 if (IS_ERR(str))
493 goto exit_free;
494 entry->rule.buflen += f->val;
495
496 err = audit_to_watch(&entry->rule, str, f->val, f->op);
497 if (err) {
498 kfree(str);
499 goto exit_free;
500 }
501 break;
502 case AUDIT_DIR:
503 str = audit_unpack_string(&bufp, &remain, f->val);
504 if (IS_ERR(str))
505 goto exit_free;
506 entry->rule.buflen += f->val;
507
508 err = audit_make_tree(&entry->rule, str, f->op);
509 kfree(str);
510 if (err)
511 goto exit_free;
512 break;
513 case AUDIT_INODE:
514 err = audit_to_inode(&entry->rule, f);
515 if (err)
516 goto exit_free;
517 break;
518 case AUDIT_FILTERKEY:
519 if (entry->rule.filterkey || f->val > AUDIT_MAX_KEY_LEN)
520 goto exit_free;
521 str = audit_unpack_string(&bufp, &remain, f->val);
522 if (IS_ERR(str))
523 goto exit_free;
524 entry->rule.buflen += f->val;
525 entry->rule.filterkey = str;
526 break;
527 }
528 }
529
530 if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal)
531 entry->rule.inode_f = NULL;
532
533 exit_nofree:
534 return entry;
535
536 exit_free:
537 if (entry->rule.watch)
538 audit_put_watch(entry->rule.watch); /* matches initial get */
539 if (entry->rule.tree)
540 audit_put_tree(entry->rule.tree); /* that's the temporary one */
541 audit_free_rule(entry);
542 return ERR_PTR(err);
543 }
544
545 /* Pack a filter field's string representation into data block. */
546 static inline size_t audit_pack_string(void **bufp, const char *str)
547 {
548 size_t len = strlen(str);
549
550 memcpy(*bufp, str, len);
551 *bufp += len;
552
553 return len;
554 }
555
556 /* Translate kernel rule respresentation to struct audit_rule_data. */
557 static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule)
558 {
559 struct audit_rule_data *data;
560 void *bufp;
561 int i;
562
563 data = kmalloc(sizeof(*data) + krule->buflen, GFP_KERNEL);
564 if (unlikely(!data))
565 return NULL;
566 memset(data, 0, sizeof(*data));
567
568 data->flags = krule->flags | krule->listnr;
569 data->action = krule->action;
570 data->field_count = krule->field_count;
571 bufp = data->buf;
572 for (i = 0; i < data->field_count; i++) {
573 struct audit_field *f = &krule->fields[i];
574
575 data->fields[i] = f->type;
576 data->fieldflags[i] = audit_ops[f->op];
577 switch(f->type) {
578 case AUDIT_SUBJ_USER:
579 case AUDIT_SUBJ_ROLE:
580 case AUDIT_SUBJ_TYPE:
581 case AUDIT_SUBJ_SEN:
582 case AUDIT_SUBJ_CLR:
583 case AUDIT_OBJ_USER:
584 case AUDIT_OBJ_ROLE:
585 case AUDIT_OBJ_TYPE:
586 case AUDIT_OBJ_LEV_LOW:
587 case AUDIT_OBJ_LEV_HIGH:
588 data->buflen += data->values[i] =
589 audit_pack_string(&bufp, f->lsm_str);
590 break;
591 case AUDIT_WATCH:
592 data->buflen += data->values[i] =
593 audit_pack_string(&bufp,
594 audit_watch_path(krule->watch));
595 break;
596 case AUDIT_DIR:
597 data->buflen += data->values[i] =
598 audit_pack_string(&bufp,
599 audit_tree_path(krule->tree));
600 break;
601 case AUDIT_FILTERKEY:
602 data->buflen += data->values[i] =
603 audit_pack_string(&bufp, krule->filterkey);
604 break;
605 default:
606 data->values[i] = f->val;
607 }
608 }
609 for (i = 0; i < AUDIT_BITMASK_SIZE; i++) data->mask[i] = krule->mask[i];
610
611 return data;
612 }
613
614 /* Compare two rules in kernel format. Considered success if rules
615 * don't match. */
616 static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
617 {
618 int i;
619
620 if (a->flags != b->flags ||
621 a->listnr != b->listnr ||
622 a->action != b->action ||
623 a->field_count != b->field_count)
624 return 1;
625
626 for (i = 0; i < a->field_count; i++) {
627 if (a->fields[i].type != b->fields[i].type ||
628 a->fields[i].op != b->fields[i].op)
629 return 1;
630
631 switch(a->fields[i].type) {
632 case AUDIT_SUBJ_USER:
633 case AUDIT_SUBJ_ROLE:
634 case AUDIT_SUBJ_TYPE:
635 case AUDIT_SUBJ_SEN:
636 case AUDIT_SUBJ_CLR:
637 case AUDIT_OBJ_USER:
638 case AUDIT_OBJ_ROLE:
639 case AUDIT_OBJ_TYPE:
640 case AUDIT_OBJ_LEV_LOW:
641 case AUDIT_OBJ_LEV_HIGH:
642 if (strcmp(a->fields[i].lsm_str, b->fields[i].lsm_str))
643 return 1;
644 break;
645 case AUDIT_WATCH:
646 if (strcmp(audit_watch_path(a->watch),
647 audit_watch_path(b->watch)))
648 return 1;
649 break;
650 case AUDIT_DIR:
651 if (strcmp(audit_tree_path(a->tree),
652 audit_tree_path(b->tree)))
653 return 1;
654 break;
655 case AUDIT_FILTERKEY:
656 /* both filterkeys exist based on above type compare */
657 if (strcmp(a->filterkey, b->filterkey))
658 return 1;
659 break;
660 case AUDIT_UID:
661 case AUDIT_EUID:
662 case AUDIT_SUID:
663 case AUDIT_FSUID:
664 case AUDIT_LOGINUID:
665 case AUDIT_OBJ_UID:
666 if (!uid_eq(a->fields[i].uid, b->fields[i].uid))
667 return 1;
668 break;
669 case AUDIT_GID:
670 case AUDIT_EGID:
671 case AUDIT_SGID:
672 case AUDIT_FSGID:
673 case AUDIT_OBJ_GID:
674 if (!gid_eq(a->fields[i].gid, b->fields[i].gid))
675 return 1;
676 break;
677 default:
678 if (a->fields[i].val != b->fields[i].val)
679 return 1;
680 }
681 }
682
683 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
684 if (a->mask[i] != b->mask[i])
685 return 1;
686
687 return 0;
688 }
689
690 /* Duplicate LSM field information. The lsm_rule is opaque, so must be
691 * re-initialized. */
692 static inline int audit_dupe_lsm_field(struct audit_field *df,
693 struct audit_field *sf)
694 {
695 int ret = 0;
696 char *lsm_str;
697
698 /* our own copy of lsm_str */
699 lsm_str = kstrdup(sf->lsm_str, GFP_KERNEL);
700 if (unlikely(!lsm_str))
701 return -ENOMEM;
702 df->lsm_str = lsm_str;
703
704 /* our own (refreshed) copy of lsm_rule */
705 ret = security_audit_rule_init(df->type, df->op, df->lsm_str,
706 (void **)&df->lsm_rule);
707 /* Keep currently invalid fields around in case they
708 * become valid after a policy reload. */
709 if (ret == -EINVAL) {
710 printk(KERN_WARNING "audit rule for LSM \'%s\' is "
711 "invalid\n", df->lsm_str);
712 ret = 0;
713 }
714
715 return ret;
716 }
717
718 /* Duplicate an audit rule. This will be a deep copy with the exception
719 * of the watch - that pointer is carried over. The LSM specific fields
720 * will be updated in the copy. The point is to be able to replace the old
721 * rule with the new rule in the filterlist, then free the old rule.
722 * The rlist element is undefined; list manipulations are handled apart from
723 * the initial copy. */
724 struct audit_entry *audit_dupe_rule(struct audit_krule *old)
725 {
726 u32 fcount = old->field_count;
727 struct audit_entry *entry;
728 struct audit_krule *new;
729 char *fk;
730 int i, err = 0;
731
732 entry = audit_init_entry(fcount);
733 if (unlikely(!entry))
734 return ERR_PTR(-ENOMEM);
735
736 new = &entry->rule;
737 new->vers_ops = old->vers_ops;
738 new->flags = old->flags;
739 new->listnr = old->listnr;
740 new->action = old->action;
741 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
742 new->mask[i] = old->mask[i];
743 new->prio = old->prio;
744 new->buflen = old->buflen;
745 new->inode_f = old->inode_f;
746 new->field_count = old->field_count;
747
748 /*
749 * note that we are OK with not refcounting here; audit_match_tree()
750 * never dereferences tree and we can't get false positives there
751 * since we'd have to have rule gone from the list *and* removed
752 * before the chunks found by lookup had been allocated, i.e. before
753 * the beginning of list scan.
754 */
755 new->tree = old->tree;
756 memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount);
757
758 /* deep copy this information, updating the lsm_rule fields, because
759 * the originals will all be freed when the old rule is freed. */
760 for (i = 0; i < fcount; i++) {
761 switch (new->fields[i].type) {
762 case AUDIT_SUBJ_USER:
763 case AUDIT_SUBJ_ROLE:
764 case AUDIT_SUBJ_TYPE:
765 case AUDIT_SUBJ_SEN:
766 case AUDIT_SUBJ_CLR:
767 case AUDIT_OBJ_USER:
768 case AUDIT_OBJ_ROLE:
769 case AUDIT_OBJ_TYPE:
770 case AUDIT_OBJ_LEV_LOW:
771 case AUDIT_OBJ_LEV_HIGH:
772 err = audit_dupe_lsm_field(&new->fields[i],
773 &old->fields[i]);
774 break;
775 case AUDIT_FILTERKEY:
776 fk = kstrdup(old->filterkey, GFP_KERNEL);
777 if (unlikely(!fk))
778 err = -ENOMEM;
779 else
780 new->filterkey = fk;
781 }
782 if (err) {
783 audit_free_rule(entry);
784 return ERR_PTR(err);
785 }
786 }
787
788 if (old->watch) {
789 audit_get_watch(old->watch);
790 new->watch = old->watch;
791 }
792
793 return entry;
794 }
795
796 /* Find an existing audit rule.
797 * Caller must hold audit_filter_mutex to prevent stale rule data. */
798 static struct audit_entry *audit_find_rule(struct audit_entry *entry,
799 struct list_head **p)
800 {
801 struct audit_entry *e, *found = NULL;
802 struct list_head *list;
803 int h;
804
805 if (entry->rule.inode_f) {
806 h = audit_hash_ino(entry->rule.inode_f->val);
807 *p = list = &audit_inode_hash[h];
808 } else if (entry->rule.watch) {
809 /* we don't know the inode number, so must walk entire hash */
810 for (h = 0; h < AUDIT_INODE_BUCKETS; h++) {
811 list = &audit_inode_hash[h];
812 list_for_each_entry(e, list, list)
813 if (!audit_compare_rule(&entry->rule, &e->rule)) {
814 found = e;
815 goto out;
816 }
817 }
818 goto out;
819 } else {
820 *p = list = &audit_filter_list[entry->rule.listnr];
821 }
822
823 list_for_each_entry(e, list, list)
824 if (!audit_compare_rule(&entry->rule, &e->rule)) {
825 found = e;
826 goto out;
827 }
828
829 out:
830 return found;
831 }
832
833 static u64 prio_low = ~0ULL/2;
834 static u64 prio_high = ~0ULL/2 - 1;
835
836 /* Add rule to given filterlist if not a duplicate. */
837 static inline int audit_add_rule(struct audit_entry *entry)
838 {
839 struct audit_entry *e;
840 struct audit_watch *watch = entry->rule.watch;
841 struct audit_tree *tree = entry->rule.tree;
842 struct list_head *list;
843 int err;
844 #ifdef CONFIG_AUDITSYSCALL
845 int dont_count = 0;
846
847 /* If either of these, don't count towards total */
848 if (entry->rule.listnr == AUDIT_FILTER_USER ||
849 entry->rule.listnr == AUDIT_FILTER_TYPE)
850 dont_count = 1;
851 #endif
852
853 mutex_lock(&audit_filter_mutex);
854 e = audit_find_rule(entry, &list);
855 if (e) {
856 mutex_unlock(&audit_filter_mutex);
857 err = -EEXIST;
858 /* normally audit_add_tree_rule() will free it on failure */
859 if (tree)
860 audit_put_tree(tree);
861 goto error;
862 }
863
864 if (watch) {
865 /* audit_filter_mutex is dropped and re-taken during this call */
866 err = audit_add_watch(&entry->rule, &list);
867 if (err) {
868 mutex_unlock(&audit_filter_mutex);
869 /*
870 * normally audit_add_tree_rule() will free it
871 * on failure
872 */
873 if (tree)
874 audit_put_tree(tree);
875 goto error;
876 }
877 }
878 if (tree) {
879 err = audit_add_tree_rule(&entry->rule);
880 if (err) {
881 mutex_unlock(&audit_filter_mutex);
882 goto error;
883 }
884 }
885
886 entry->rule.prio = ~0ULL;
887 if (entry->rule.listnr == AUDIT_FILTER_EXIT) {
888 if (entry->rule.flags & AUDIT_FILTER_PREPEND)
889 entry->rule.prio = ++prio_high;
890 else
891 entry->rule.prio = --prio_low;
892 }
893
894 if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
895 list_add(&entry->rule.list,
896 &audit_rules_list[entry->rule.listnr]);
897 list_add_rcu(&entry->list, list);
898 entry->rule.flags &= ~AUDIT_FILTER_PREPEND;
899 } else {
900 list_add_tail(&entry->rule.list,
901 &audit_rules_list[entry->rule.listnr]);
902 list_add_tail_rcu(&entry->list, list);
903 }
904 #ifdef CONFIG_AUDITSYSCALL
905 if (!dont_count)
906 audit_n_rules++;
907
908 if (!audit_match_signal(entry))
909 audit_signals++;
910 #endif
911 mutex_unlock(&audit_filter_mutex);
912
913 return 0;
914
915 error:
916 if (watch)
917 audit_put_watch(watch); /* tmp watch, matches initial get */
918 return err;
919 }
920
921 /* Remove an existing rule from filterlist. */
922 static inline int audit_del_rule(struct audit_entry *entry)
923 {
924 struct audit_entry *e;
925 struct audit_watch *watch = entry->rule.watch;
926 struct audit_tree *tree = entry->rule.tree;
927 struct list_head *list;
928 int ret = 0;
929 #ifdef CONFIG_AUDITSYSCALL
930 int dont_count = 0;
931
932 /* If either of these, don't count towards total */
933 if (entry->rule.listnr == AUDIT_FILTER_USER ||
934 entry->rule.listnr == AUDIT_FILTER_TYPE)
935 dont_count = 1;
936 #endif
937
938 mutex_lock(&audit_filter_mutex);
939 e = audit_find_rule(entry, &list);
940 if (!e) {
941 mutex_unlock(&audit_filter_mutex);
942 ret = -ENOENT;
943 goto out;
944 }
945
946 if (e->rule.watch)
947 audit_remove_watch_rule(&e->rule);
948
949 if (e->rule.tree)
950 audit_remove_tree_rule(&e->rule);
951
952 list_del_rcu(&e->list);
953 list_del(&e->rule.list);
954 call_rcu(&e->rcu, audit_free_rule_rcu);
955
956 #ifdef CONFIG_AUDITSYSCALL
957 if (!dont_count)
958 audit_n_rules--;
959
960 if (!audit_match_signal(entry))
961 audit_signals--;
962 #endif
963 mutex_unlock(&audit_filter_mutex);
964
965 out:
966 if (watch)
967 audit_put_watch(watch); /* match initial get */
968 if (tree)
969 audit_put_tree(tree); /* that's the temporary one */
970
971 return ret;
972 }
973
974 /* List rules using struct audit_rule_data. */
975 static void audit_list_rules(__u32 portid, int seq, struct sk_buff_head *q)
976 {
977 struct sk_buff *skb;
978 struct audit_krule *r;
979 int i;
980
981 /* This is a blocking read, so use audit_filter_mutex instead of rcu
982 * iterator to sync with list writers. */
983 for (i=0; i<AUDIT_NR_FILTERS; i++) {
984 list_for_each_entry(r, &audit_rules_list[i], list) {
985 struct audit_rule_data *data;
986
987 data = audit_krule_to_data(r);
988 if (unlikely(!data))
989 break;
990 skb = audit_make_reply(portid, seq, AUDIT_LIST_RULES,
991 0, 1, data,
992 sizeof(*data) + data->buflen);
993 if (skb)
994 skb_queue_tail(q, skb);
995 kfree(data);
996 }
997 }
998 skb = audit_make_reply(portid, seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);
999 if (skb)
1000 skb_queue_tail(q, skb);
1001 }
1002
1003 /* Log rule additions and removals */
1004 static void audit_log_rule_change(char *action, struct audit_krule *rule, int res)
1005 {
1006 struct audit_buffer *ab;
1007 uid_t loginuid = from_kuid(&init_user_ns, audit_get_loginuid(current));
1008 unsigned int sessionid = audit_get_sessionid(current);
1009
1010 if (!audit_enabled)
1011 return;
1012
1013 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
1014 if (!ab)
1015 return;
1016 audit_log_format(ab, "auid=%u ses=%u" ,loginuid, sessionid);
1017 audit_log_task_context(ab);
1018 audit_log_format(ab, " op=");
1019 audit_log_string(ab, action);
1020 audit_log_key(ab, rule->filterkey);
1021 audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
1022 audit_log_end(ab);
1023 }
1024
1025 /**
1026 * audit_rule_change - apply all rules to the specified message type
1027 * @type: audit message type
1028 * @portid: target port id for netlink audit messages
1029 * @seq: netlink audit message sequence (serial) number
1030 * @data: payload data
1031 * @datasz: size of payload data
1032 */
1033 int audit_rule_change(int type, __u32 portid, int seq, void *data,
1034 size_t datasz)
1035 {
1036 int err = 0;
1037 struct audit_entry *entry;
1038
1039 switch (type) {
1040 case AUDIT_ADD_RULE:
1041 entry = audit_data_to_entry(data, datasz);
1042 if (IS_ERR(entry))
1043 return PTR_ERR(entry);
1044
1045 err = audit_add_rule(entry);
1046 audit_log_rule_change("add rule", &entry->rule, !err);
1047 if (err)
1048 audit_free_rule(entry);
1049 break;
1050 case AUDIT_DEL_RULE:
1051 entry = audit_data_to_entry(data, datasz);
1052 if (IS_ERR(entry))
1053 return PTR_ERR(entry);
1054
1055 err = audit_del_rule(entry);
1056 audit_log_rule_change("remove rule", &entry->rule, !err);
1057 audit_free_rule(entry);
1058 break;
1059 default:
1060 return -EINVAL;
1061 }
1062
1063 return err;
1064 }
1065
1066 /**
1067 * audit_list_rules_send - list the audit rules
1068 * @portid: target portid for netlink audit messages
1069 * @seq: netlink audit message sequence (serial) number
1070 */
1071 int audit_list_rules_send(__u32 portid, int seq)
1072 {
1073 struct task_struct *tsk;
1074 struct audit_netlink_list *dest;
1075 int err = 0;
1076
1077 /* We can't just spew out the rules here because we might fill
1078 * the available socket buffer space and deadlock waiting for
1079 * auditctl to read from it... which isn't ever going to
1080 * happen if we're actually running in the context of auditctl
1081 * trying to _send_ the stuff */
1082
1083 dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL);
1084 if (!dest)
1085 return -ENOMEM;
1086 dest->portid = portid;
1087 dest->pid = task_pid_vnr(current);
1088 skb_queue_head_init(&dest->q);
1089
1090 mutex_lock(&audit_filter_mutex);
1091 audit_list_rules(portid, seq, &dest->q);
1092 mutex_unlock(&audit_filter_mutex);
1093
1094 tsk = kthread_run(audit_send_list, dest, "audit_send_list");
1095 if (IS_ERR(tsk)) {
1096 skb_queue_purge(&dest->q);
1097 kfree(dest);
1098 err = PTR_ERR(tsk);
1099 }
1100
1101 return err;
1102 }
1103
1104 int audit_comparator(u32 left, u32 op, u32 right)
1105 {
1106 switch (op) {
1107 case Audit_equal:
1108 return (left == right);
1109 case Audit_not_equal:
1110 return (left != right);
1111 case Audit_lt:
1112 return (left < right);
1113 case Audit_le:
1114 return (left <= right);
1115 case Audit_gt:
1116 return (left > right);
1117 case Audit_ge:
1118 return (left >= right);
1119 case Audit_bitmask:
1120 return (left & right);
1121 case Audit_bittest:
1122 return ((left & right) == right);
1123 default:
1124 BUG();
1125 return 0;
1126 }
1127 }
1128
1129 int audit_uid_comparator(kuid_t left, u32 op, kuid_t right)
1130 {
1131 switch (op) {
1132 case Audit_equal:
1133 return uid_eq(left, right);
1134 case Audit_not_equal:
1135 return !uid_eq(left, right);
1136 case Audit_lt:
1137 return uid_lt(left, right);
1138 case Audit_le:
1139 return uid_lte(left, right);
1140 case Audit_gt:
1141 return uid_gt(left, right);
1142 case Audit_ge:
1143 return uid_gte(left, right);
1144 case Audit_bitmask:
1145 case Audit_bittest:
1146 default:
1147 BUG();
1148 return 0;
1149 }
1150 }
1151
1152 int audit_gid_comparator(kgid_t left, u32 op, kgid_t right)
1153 {
1154 switch (op) {
1155 case Audit_equal:
1156 return gid_eq(left, right);
1157 case Audit_not_equal:
1158 return !gid_eq(left, right);
1159 case Audit_lt:
1160 return gid_lt(left, right);
1161 case Audit_le:
1162 return gid_lte(left, right);
1163 case Audit_gt:
1164 return gid_gt(left, right);
1165 case Audit_ge:
1166 return gid_gte(left, right);
1167 case Audit_bitmask:
1168 case Audit_bittest:
1169 default:
1170 BUG();
1171 return 0;
1172 }
1173 }
1174
1175 /**
1176 * parent_len - find the length of the parent portion of a pathname
1177 * @path: pathname of which to determine length
1178 */
1179 int parent_len(const char *path)
1180 {
1181 int plen;
1182 const char *p;
1183
1184 plen = strlen(path);
1185
1186 if (plen == 0)
1187 return plen;
1188
1189 /* disregard trailing slashes */
1190 p = path + plen - 1;
1191 while ((*p == '/') && (p > path))
1192 p--;
1193
1194 /* walk backward until we find the next slash or hit beginning */
1195 while ((*p != '/') && (p > path))
1196 p--;
1197
1198 /* did we find a slash? Then increment to include it in path */
1199 if (*p == '/')
1200 p++;
1201
1202 return p - path;
1203 }
1204
1205 /**
1206 * audit_compare_dname_path - compare given dentry name with last component in
1207 * given path. Return of 0 indicates a match.
1208 * @dname: dentry name that we're comparing
1209 * @path: full pathname that we're comparing
1210 * @parentlen: length of the parent if known. Passing in AUDIT_NAME_FULL
1211 * here indicates that we must compute this value.
1212 */
1213 int audit_compare_dname_path(const char *dname, const char *path, int parentlen)
1214 {
1215 int dlen, pathlen;
1216 const char *p;
1217
1218 dlen = strlen(dname);
1219 pathlen = strlen(path);
1220 if (pathlen < dlen)
1221 return 1;
1222
1223 parentlen = parentlen == AUDIT_NAME_FULL ? parent_len(path) : parentlen;
1224 if (pathlen - parentlen != dlen)
1225 return 1;
1226
1227 p = path + parentlen;
1228
1229 return strncmp(p, dname, dlen);
1230 }
1231
1232 static int audit_filter_user_rules(struct audit_krule *rule, int type,
1233 enum audit_state *state)
1234 {
1235 int i;
1236
1237 for (i = 0; i < rule->field_count; i++) {
1238 struct audit_field *f = &rule->fields[i];
1239 int result = 0;
1240 u32 sid;
1241
1242 switch (f->type) {
1243 case AUDIT_PID:
1244 result = audit_comparator(task_pid_vnr(current), f->op, f->val);
1245 break;
1246 case AUDIT_UID:
1247 result = audit_uid_comparator(current_uid(), f->op, f->uid);
1248 break;
1249 case AUDIT_GID:
1250 result = audit_gid_comparator(current_gid(), f->op, f->gid);
1251 break;
1252 case AUDIT_LOGINUID:
1253 result = audit_uid_comparator(audit_get_loginuid(current),
1254 f->op, f->uid);
1255 break;
1256 case AUDIT_LOGINUID_SET:
1257 result = audit_comparator(audit_loginuid_set(current),
1258 f->op, f->val);
1259 break;
1260 case AUDIT_MSGTYPE:
1261 result = audit_comparator(type, f->op, f->val);
1262 break;
1263 case AUDIT_SUBJ_USER:
1264 case AUDIT_SUBJ_ROLE:
1265 case AUDIT_SUBJ_TYPE:
1266 case AUDIT_SUBJ_SEN:
1267 case AUDIT_SUBJ_CLR:
1268 if (f->lsm_rule) {
1269 security_task_getsecid(current, &sid);
1270 result = security_audit_rule_match(sid,
1271 f->type,
1272 f->op,
1273 f->lsm_rule,
1274 NULL);
1275 }
1276 break;
1277 }
1278
1279 if (!result)
1280 return 0;
1281 }
1282 switch (rule->action) {
1283 case AUDIT_NEVER: *state = AUDIT_DISABLED; break;
1284 case AUDIT_ALWAYS: *state = AUDIT_RECORD_CONTEXT; break;
1285 }
1286 return 1;
1287 }
1288
1289 int audit_filter_user(int type)
1290 {
1291 enum audit_state state = AUDIT_DISABLED;
1292 struct audit_entry *e;
1293 int rc, ret;
1294
1295 ret = 1; /* Audit by default */
1296
1297 rcu_read_lock();
1298 list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_USER], list) {
1299 rc = audit_filter_user_rules(&e->rule, type, &state);
1300 if (rc) {
1301 if (rc > 0 && state == AUDIT_DISABLED)
1302 ret = 0;
1303 break;
1304 }
1305 }
1306 rcu_read_unlock();
1307
1308 return ret;
1309 }
1310
1311 int audit_filter_type(int type)
1312 {
1313 struct audit_entry *e;
1314 int result = 0;
1315
1316 rcu_read_lock();
1317 if (list_empty(&audit_filter_list[AUDIT_FILTER_TYPE]))
1318 goto unlock_and_return;
1319
1320 list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_TYPE],
1321 list) {
1322 int i;
1323 for (i = 0; i < e->rule.field_count; i++) {
1324 struct audit_field *f = &e->rule.fields[i];
1325 if (f->type == AUDIT_MSGTYPE) {
1326 result = audit_comparator(type, f->op, f->val);
1327 if (!result)
1328 break;
1329 }
1330 }
1331 if (result)
1332 goto unlock_and_return;
1333 }
1334 unlock_and_return:
1335 rcu_read_unlock();
1336 return result;
1337 }
1338
1339 static int update_lsm_rule(struct audit_krule *r)
1340 {
1341 struct audit_entry *entry = container_of(r, struct audit_entry, rule);
1342 struct audit_entry *nentry;
1343 int err = 0;
1344
1345 if (!security_audit_rule_known(r))
1346 return 0;
1347
1348 nentry = audit_dupe_rule(r);
1349 if (IS_ERR(nentry)) {
1350 /* save the first error encountered for the
1351 * return value */
1352 err = PTR_ERR(nentry);
1353 audit_panic("error updating LSM filters");
1354 if (r->watch)
1355 list_del(&r->rlist);
1356 list_del_rcu(&entry->list);
1357 list_del(&r->list);
1358 } else {
1359 if (r->watch || r->tree)
1360 list_replace_init(&r->rlist, &nentry->rule.rlist);
1361 list_replace_rcu(&entry->list, &nentry->list);
1362 list_replace(&r->list, &nentry->rule.list);
1363 }
1364 call_rcu(&entry->rcu, audit_free_rule_rcu);
1365
1366 return err;
1367 }
1368
1369 /* This function will re-initialize the lsm_rule field of all applicable rules.
1370 * It will traverse the filter lists serarching for rules that contain LSM
1371 * specific filter fields. When such a rule is found, it is copied, the
1372 * LSM field is re-initialized, and the old rule is replaced with the
1373 * updated rule. */
1374 int audit_update_lsm_rules(void)
1375 {
1376 struct audit_krule *r, *n;
1377 int i, err = 0;
1378
1379 /* audit_filter_mutex synchronizes the writers */
1380 mutex_lock(&audit_filter_mutex);
1381
1382 for (i = 0; i < AUDIT_NR_FILTERS; i++) {
1383 list_for_each_entry_safe(r, n, &audit_rules_list[i], list) {
1384 int res = update_lsm_rule(r);
1385 if (!err)
1386 err = res;
1387 }
1388 }
1389 mutex_unlock(&audit_filter_mutex);
1390
1391 return err;
1392 }
Linux with added FPC-III support