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1 | /* auditfilter.c -- filtering of audit events |
2 | * |
3 | * Copyright 2003-2004 Red Hat, Inc. |
4 | * Copyright 2005 Hewlett-Packard Development Company, L.P. |
5 | * Copyright 2005 IBM Corporation |
6 | * |
7 | * This program is free software; you can redistribute it and/or modify |
8 | * it under the terms of the GNU General Public License as published by |
9 | * the Free Software Foundation; either version 2 of the License, or |
10 | * (at your option) any later version. |
11 | * |
12 | * This program is distributed in the hope that it will be useful, |
13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
15 | * GNU General Public License for more details. |
16 | * |
17 | * You should have received a copy of the GNU General Public License |
18 | * along with this program; if not, write to the Free Software |
19 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
20 | */ |
21 | |
22 | #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 | |
314 | /* Translate struct audit_rule to kernel's rule respresentation. |
315 | * Exists for backward compatibility with userspace. */ |
316 | static struct audit_entry *audit_rule_to_entry(struct audit_rule *rule) |
317 | { |
318 | struct audit_entry *entry; |
319 | int err = 0; |
320 | int i; |
321 | |
322 | entry = audit_to_entry_common(rule); |
323 | if (IS_ERR(entry)) |
324 | goto exit_nofree; |
325 | |
326 | for (i = 0; i < rule->field_count; i++) { |
327 | struct audit_field *f = &entry->rule.fields[i]; |
328 | u32 n; |
329 | |
330 | n = rule->fields[i] & (AUDIT_NEGATE|AUDIT_OPERATORS); |
331 | |
332 | /* Support for legacy operators where |
333 | * AUDIT_NEGATE bit signifies != and otherwise assumes == */ |
334 | if (n & AUDIT_NEGATE) |
335 | f->op = Audit_not_equal; |
336 | else if (!n) |
337 | f->op = Audit_equal; |
338 | else |
339 | f->op = audit_to_op(n); |
340 | |
341 | entry->rule.vers_ops = (n & AUDIT_OPERATORS) ? 2 : 1; |
342 | |
343 | f->type = rule->fields[i] & ~(AUDIT_NEGATE|AUDIT_OPERATORS); |
344 | f->val = rule->values[i]; |
345 | f->uid = INVALID_UID; |
346 | f->gid = INVALID_GID; |
347 | |
348 | err = -EINVAL; |
349 | if (f->op == Audit_bad) |
350 | goto exit_free; |
351 | |
352 | switch(f->type) { |
353 | default: |
354 | goto exit_free; |
355 | case AUDIT_UID: |
356 | case AUDIT_EUID: |
357 | case AUDIT_SUID: |
358 | case AUDIT_FSUID: |
359 | case AUDIT_LOGINUID: |
360 | /* bit ops not implemented for uid comparisons */ |
361 | if (f->op == Audit_bitmask || f->op == Audit_bittest) |
362 | goto exit_free; |
363 | |
364 | f->uid = make_kuid(current_user_ns(), f->val); |
365 | if (!uid_valid(f->uid)) |
366 | goto exit_free; |
367 | break; |
368 | case AUDIT_GID: |
369 | case AUDIT_EGID: |
370 | case AUDIT_SGID: |
371 | case AUDIT_FSGID: |
372 | /* bit ops not implemented for gid comparisons */ |
373 | if (f->op == Audit_bitmask || f->op == Audit_bittest) |
374 | goto exit_free; |
375 | |
376 | f->gid = make_kgid(current_user_ns(), f->val); |
377 | if (!gid_valid(f->gid)) |
378 | goto exit_free; |
379 | break; |
380 | case AUDIT_PID: |
381 | case AUDIT_PERS: |
382 | case AUDIT_MSGTYPE: |
383 | case AUDIT_PPID: |
384 | case AUDIT_DEVMAJOR: |
385 | case AUDIT_DEVMINOR: |
386 | case AUDIT_EXIT: |
387 | case AUDIT_SUCCESS: |
388 | /* bit ops are only useful on syscall args */ |
389 | if (f->op == Audit_bitmask || f->op == Audit_bittest) |
390 | goto exit_free; |
391 | break; |
392 | case AUDIT_ARG0: |
393 | case AUDIT_ARG1: |
394 | case AUDIT_ARG2: |
395 | case AUDIT_ARG3: |
396 | break; |
397 | /* arch is only allowed to be = or != */ |
398 | case AUDIT_ARCH: |
399 | if (f->op != Audit_not_equal && f->op != Audit_equal) |
400 | goto exit_free; |
401 | entry->rule.arch_f = f; |
402 | break; |
403 | case AUDIT_PERM: |
404 | if (f->val & ~15) |
405 | goto exit_free; |
406 | break; |
407 | case AUDIT_FILETYPE: |
408 | if (f->val & ~S_IFMT) |
409 | goto exit_free; |
410 | break; |
411 | case AUDIT_INODE: |
412 | err = audit_to_inode(&entry->rule, f); |
413 | if (err) |
414 | goto exit_free; |
415 | break; |
416 | } |
417 | } |
418 | |
419 | if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal) |
420 | entry->rule.inode_f = NULL; |
421 | |
422 | exit_nofree: |
423 | return entry; |
424 | |
425 | exit_free: |
426 | audit_free_rule(entry); |
427 | return ERR_PTR(err); |
428 | } |
429 | |
430 | /* Translate struct audit_rule_data to kernel's rule respresentation. */ |
431 | static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data, |
432 | size_t datasz) |
433 | { |
434 | int err = 0; |
435 | struct audit_entry *entry; |
436 | void *bufp; |
437 | size_t remain = datasz - sizeof(struct audit_rule_data); |
438 | int i; |
439 | char *str; |
440 | |
441 | entry = audit_to_entry_common((struct audit_rule *)data); |
442 | if (IS_ERR(entry)) |
443 | goto exit_nofree; |
444 | |
445 | bufp = data->buf; |
446 | entry->rule.vers_ops = 2; |
447 | for (i = 0; i < data->field_count; i++) { |
448 | struct audit_field *f = &entry->rule.fields[i]; |
449 | |
450 | err = -EINVAL; |
451 | |
452 | f->op = audit_to_op(data->fieldflags[i]); |
453 | if (f->op == Audit_bad) |
454 | goto exit_free; |
455 | |
456 | f->type = data->fields[i]; |
457 | f->val = data->values[i]; |
458 | f->uid = INVALID_UID; |
459 | f->gid = INVALID_GID; |
460 | f->lsm_str = NULL; |
461 | f->lsm_rule = NULL; |
462 | switch(f->type) { |
463 | case AUDIT_UID: |
464 | case AUDIT_EUID: |
465 | case AUDIT_SUID: |
466 | case AUDIT_FSUID: |
467 | case AUDIT_LOGINUID: |
468 | case AUDIT_OBJ_UID: |
469 | /* bit ops not implemented for uid comparisons */ |
470 | if (f->op == Audit_bitmask || f->op == Audit_bittest) |
471 | goto exit_free; |
472 | |
473 | f->uid = make_kuid(current_user_ns(), f->val); |
474 | if (!uid_valid(f->uid)) |
475 | goto exit_free; |
476 | break; |
477 | case AUDIT_GID: |
478 | case AUDIT_EGID: |
479 | case AUDIT_SGID: |
480 | case AUDIT_FSGID: |
481 | case AUDIT_OBJ_GID: |
482 | /* bit ops not implemented for gid comparisons */ |
483 | if (f->op == Audit_bitmask || f->op == Audit_bittest) |
484 | goto exit_free; |
485 | |
486 | f->gid = make_kgid(current_user_ns(), f->val); |
487 | if (!gid_valid(f->gid)) |
488 | goto exit_free; |
489 | break; |
490 | case AUDIT_PID: |
491 | case AUDIT_PERS: |
492 | case AUDIT_MSGTYPE: |
493 | case AUDIT_PPID: |
494 | case AUDIT_DEVMAJOR: |
495 | case AUDIT_DEVMINOR: |
496 | case AUDIT_EXIT: |
497 | case AUDIT_SUCCESS: |
498 | case AUDIT_ARG0: |
499 | case AUDIT_ARG1: |
500 | case AUDIT_ARG2: |
501 | case AUDIT_ARG3: |
502 | break; |
503 | case AUDIT_ARCH: |
504 | entry->rule.arch_f = f; |
505 | break; |
506 | case AUDIT_SUBJ_USER: |
507 | case AUDIT_SUBJ_ROLE: |
508 | case AUDIT_SUBJ_TYPE: |
509 | case AUDIT_SUBJ_SEN: |
510 | case AUDIT_SUBJ_CLR: |
511 | case AUDIT_OBJ_USER: |
512 | case AUDIT_OBJ_ROLE: |
513 | case AUDIT_OBJ_TYPE: |
514 | case AUDIT_OBJ_LEV_LOW: |
515 | case AUDIT_OBJ_LEV_HIGH: |
516 | str = audit_unpack_string(&bufp, &remain, f->val); |
517 | if (IS_ERR(str)) |
518 | goto exit_free; |
519 | entry->rule.buflen += f->val; |
520 | |
521 | err = security_audit_rule_init(f->type, f->op, str, |
522 | (void **)&f->lsm_rule); |
523 | /* Keep currently invalid fields around in case they |
524 | * become valid after a policy reload. */ |
525 | if (err == -EINVAL) { |
526 | printk(KERN_WARNING "audit rule for LSM " |
527 | "\'%s\' is invalid\n", str); |
528 | err = 0; |
529 | } |
530 | if (err) { |
531 | kfree(str); |
532 | goto exit_free; |
533 | } else |
534 | f->lsm_str = str; |
535 | break; |
536 | case AUDIT_WATCH: |
537 | str = audit_unpack_string(&bufp, &remain, f->val); |
538 | if (IS_ERR(str)) |
539 | goto exit_free; |
540 | entry->rule.buflen += f->val; |
541 | |
542 | err = audit_to_watch(&entry->rule, str, f->val, f->op); |
543 | if (err) { |
544 | kfree(str); |
545 | goto exit_free; |
546 | } |
547 | break; |
548 | case AUDIT_DIR: |
549 | str = audit_unpack_string(&bufp, &remain, f->val); |
550 | if (IS_ERR(str)) |
551 | goto exit_free; |
552 | entry->rule.buflen += f->val; |
553 | |
554 | err = audit_make_tree(&entry->rule, str, f->op); |
555 | kfree(str); |
556 | if (err) |
557 | goto exit_free; |
558 | break; |
559 | case AUDIT_INODE: |
560 | err = audit_to_inode(&entry->rule, f); |
561 | if (err) |
562 | goto exit_free; |
563 | break; |
564 | case AUDIT_FILTERKEY: |
565 | if (entry->rule.filterkey || f->val > AUDIT_MAX_KEY_LEN) |
566 | goto exit_free; |
567 | str = audit_unpack_string(&bufp, &remain, f->val); |
568 | if (IS_ERR(str)) |
569 | goto exit_free; |
570 | entry->rule.buflen += f->val; |
571 | entry->rule.filterkey = str; |
572 | break; |
573 | case AUDIT_PERM: |
574 | if (f->val & ~15) |
575 | goto exit_free; |
576 | break; |
577 | case AUDIT_FILETYPE: |
578 | if (f->val & ~S_IFMT) |
579 | goto exit_free; |
580 | break; |
581 | case AUDIT_FIELD_COMPARE: |
582 | if (f->val > AUDIT_MAX_FIELD_COMPARE) |
583 | goto exit_free; |
584 | break; |
585 | default: |
586 | goto exit_free; |
587 | } |
588 | } |
589 | |
590 | if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal) |
591 | entry->rule.inode_f = NULL; |
592 | |
593 | exit_nofree: |
594 | return entry; |
595 | |
596 | exit_free: |
597 | audit_free_rule(entry); |
598 | return ERR_PTR(err); |
599 | } |
600 | |
601 | /* Pack a filter field's string representation into data block. */ |
602 | static inline size_t audit_pack_string(void **bufp, const char *str) |
603 | { |
604 | size_t len = strlen(str); |
605 | |
606 | memcpy(*bufp, str, len); |
607 | *bufp += len; |
608 | |
609 | return len; |
610 | } |
611 | |
612 | /* Translate kernel rule respresentation to struct audit_rule. |
613 | * Exists for backward compatibility with userspace. */ |
614 | static struct audit_rule *audit_krule_to_rule(struct audit_krule *krule) |
615 | { |
616 | struct audit_rule *rule; |
617 | int i; |
618 | |
619 | rule = kzalloc(sizeof(*rule), GFP_KERNEL); |
620 | if (unlikely(!rule)) |
621 | return NULL; |
622 | |
623 | rule->flags = krule->flags | krule->listnr; |
624 | rule->action = krule->action; |
625 | rule->field_count = krule->field_count; |
626 | for (i = 0; i < rule->field_count; i++) { |
627 | rule->values[i] = krule->fields[i].val; |
628 | rule->fields[i] = krule->fields[i].type; |
629 | |
630 | if (krule->vers_ops == 1) { |
631 | if (krule->fields[i].op == Audit_not_equal) |
632 | rule->fields[i] |= AUDIT_NEGATE; |
633 | } else { |
634 | rule->fields[i] |= audit_ops[krule->fields[i].op]; |
635 | } |
636 | } |
637 | for (i = 0; i < AUDIT_BITMASK_SIZE; i++) rule->mask[i] = krule->mask[i]; |
638 | |
639 | return rule; |
640 | } |
641 | |
642 | /* Translate kernel rule respresentation to struct audit_rule_data. */ |
643 | static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule) |
644 | { |
645 | struct audit_rule_data *data; |
646 | void *bufp; |
647 | int i; |
648 | |
649 | data = kmalloc(sizeof(*data) + krule->buflen, GFP_KERNEL); |
650 | if (unlikely(!data)) |
651 | return NULL; |
652 | memset(data, 0, sizeof(*data)); |
653 | |
654 | data->flags = krule->flags | krule->listnr; |
655 | data->action = krule->action; |
656 | data->field_count = krule->field_count; |
657 | bufp = data->buf; |
658 | for (i = 0; i < data->field_count; i++) { |
659 | struct audit_field *f = &krule->fields[i]; |
660 | |
661 | data->fields[i] = f->type; |
662 | data->fieldflags[i] = audit_ops[f->op]; |
663 | switch(f->type) { |
664 | case AUDIT_SUBJ_USER: |
665 | case AUDIT_SUBJ_ROLE: |
666 | case AUDIT_SUBJ_TYPE: |
667 | case AUDIT_SUBJ_SEN: |
668 | case AUDIT_SUBJ_CLR: |
669 | case AUDIT_OBJ_USER: |
670 | case AUDIT_OBJ_ROLE: |
671 | case AUDIT_OBJ_TYPE: |
672 | case AUDIT_OBJ_LEV_LOW: |
673 | case AUDIT_OBJ_LEV_HIGH: |
674 | data->buflen += data->values[i] = |
675 | audit_pack_string(&bufp, f->lsm_str); |
676 | break; |
677 | case AUDIT_WATCH: |
678 | data->buflen += data->values[i] = |
679 | audit_pack_string(&bufp, |
680 | audit_watch_path(krule->watch)); |
681 | break; |
682 | case AUDIT_DIR: |
683 | data->buflen += data->values[i] = |
684 | audit_pack_string(&bufp, |
685 | audit_tree_path(krule->tree)); |
686 | break; |
687 | case AUDIT_FILTERKEY: |
688 | data->buflen += data->values[i] = |
689 | audit_pack_string(&bufp, krule->filterkey); |
690 | break; |
691 | default: |
692 | data->values[i] = f->val; |
693 | } |
694 | } |
695 | for (i = 0; i < AUDIT_BITMASK_SIZE; i++) data->mask[i] = krule->mask[i]; |
696 | |
697 | return data; |
698 | } |
699 | |
700 | /* Compare two rules in kernel format. Considered success if rules |
701 | * don't match. */ |
702 | static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b) |
703 | { |
704 | int i; |
705 | |
706 | if (a->flags != b->flags || |
707 | a->listnr != b->listnr || |
708 | a->action != b->action || |
709 | a->field_count != b->field_count) |
710 | return 1; |
711 | |
712 | for (i = 0; i < a->field_count; i++) { |
713 | if (a->fields[i].type != b->fields[i].type || |
714 | a->fields[i].op != b->fields[i].op) |
715 | return 1; |
716 | |
717 | switch(a->fields[i].type) { |
718 | case AUDIT_SUBJ_USER: |
719 | case AUDIT_SUBJ_ROLE: |
720 | case AUDIT_SUBJ_TYPE: |
721 | case AUDIT_SUBJ_SEN: |
722 | case AUDIT_SUBJ_CLR: |
723 | case AUDIT_OBJ_USER: |
724 | case AUDIT_OBJ_ROLE: |
725 | case AUDIT_OBJ_TYPE: |
726 | case AUDIT_OBJ_LEV_LOW: |
727 | case AUDIT_OBJ_LEV_HIGH: |
728 | if (strcmp(a->fields[i].lsm_str, b->fields[i].lsm_str)) |
729 | return 1; |
730 | break; |
731 | case AUDIT_WATCH: |
732 | if (strcmp(audit_watch_path(a->watch), |
733 | audit_watch_path(b->watch))) |
734 | return 1; |
735 | break; |
736 | case AUDIT_DIR: |
737 | if (strcmp(audit_tree_path(a->tree), |
738 | audit_tree_path(b->tree))) |
739 | return 1; |
740 | break; |
741 | case AUDIT_FILTERKEY: |
742 | /* both filterkeys exist based on above type compare */ |
743 | if (strcmp(a->filterkey, b->filterkey)) |
744 | return 1; |
745 | break; |
746 | case AUDIT_UID: |
747 | case AUDIT_EUID: |
748 | case AUDIT_SUID: |
749 | case AUDIT_FSUID: |
750 | case AUDIT_LOGINUID: |
751 | case AUDIT_OBJ_UID: |
752 | if (!uid_eq(a->fields[i].uid, b->fields[i].uid)) |
753 | return 1; |
754 | break; |
755 | case AUDIT_GID: |
756 | case AUDIT_EGID: |
757 | case AUDIT_SGID: |
758 | case AUDIT_FSGID: |
759 | case AUDIT_OBJ_GID: |
760 | if (!gid_eq(a->fields[i].gid, b->fields[i].gid)) |
761 | return 1; |
762 | break; |
763 | default: |
764 | if (a->fields[i].val != b->fields[i].val) |
765 | return 1; |
766 | } |
767 | } |
768 | |
769 | for (i = 0; i < AUDIT_BITMASK_SIZE; i++) |
770 | if (a->mask[i] != b->mask[i]) |
771 | return 1; |
772 | |
773 | return 0; |
774 | } |
775 | |
776 | /* Duplicate LSM field information. The lsm_rule is opaque, so must be |
777 | * re-initialized. */ |
778 | static inline int audit_dupe_lsm_field(struct audit_field *df, |
779 | struct audit_field *sf) |
780 | { |
781 | int ret = 0; |
782 | char *lsm_str; |
783 | |
784 | /* our own copy of lsm_str */ |
785 | lsm_str = kstrdup(sf->lsm_str, GFP_KERNEL); |
786 | if (unlikely(!lsm_str)) |
787 | return -ENOMEM; |
788 | df->lsm_str = lsm_str; |
789 | |
790 | /* our own (refreshed) copy of lsm_rule */ |
791 | ret = security_audit_rule_init(df->type, df->op, df->lsm_str, |
792 | (void **)&df->lsm_rule); |
793 | /* Keep currently invalid fields around in case they |
794 | * become valid after a policy reload. */ |
795 | if (ret == -EINVAL) { |
796 | printk(KERN_WARNING "audit rule for LSM \'%s\' is " |
797 | "invalid\n", df->lsm_str); |
798 | ret = 0; |
799 | } |
800 | |
801 | return ret; |
802 | } |
803 | |
804 | /* Duplicate an audit rule. This will be a deep copy with the exception |
805 | * of the watch - that pointer is carried over. The LSM specific fields |
806 | * will be updated in the copy. The point is to be able to replace the old |
807 | * rule with the new rule in the filterlist, then free the old rule. |
808 | * The rlist element is undefined; list manipulations are handled apart from |
809 | * the initial copy. */ |
810 | struct audit_entry *audit_dupe_rule(struct audit_krule *old) |
811 | { |
812 | u32 fcount = old->field_count; |
813 | struct audit_entry *entry; |
814 | struct audit_krule *new; |
815 | char *fk; |
816 | int i, err = 0; |
817 | |
818 | entry = audit_init_entry(fcount); |
819 | if (unlikely(!entry)) |
820 | return ERR_PTR(-ENOMEM); |
821 | |
822 | new = &entry->rule; |
823 | new->vers_ops = old->vers_ops; |
824 | new->flags = old->flags; |
825 | new->listnr = old->listnr; |
826 | new->action = old->action; |
827 | for (i = 0; i < AUDIT_BITMASK_SIZE; i++) |
828 | new->mask[i] = old->mask[i]; |
829 | new->prio = old->prio; |
830 | new->buflen = old->buflen; |
831 | new->inode_f = old->inode_f; |
832 | new->field_count = old->field_count; |
833 | |
834 | /* |
835 | * note that we are OK with not refcounting here; audit_match_tree() |
836 | * never dereferences tree and we can't get false positives there |
837 | * since we'd have to have rule gone from the list *and* removed |
838 | * before the chunks found by lookup had been allocated, i.e. before |
839 | * the beginning of list scan. |
840 | */ |
841 | new->tree = old->tree; |
842 | memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount); |
843 | |
844 | /* deep copy this information, updating the lsm_rule fields, because |
845 | * the originals will all be freed when the old rule is freed. */ |
846 | for (i = 0; i < fcount; i++) { |
847 | switch (new->fields[i].type) { |
848 | case AUDIT_SUBJ_USER: |
849 | case AUDIT_SUBJ_ROLE: |
850 | case AUDIT_SUBJ_TYPE: |
851 | case AUDIT_SUBJ_SEN: |
852 | case AUDIT_SUBJ_CLR: |
853 | case AUDIT_OBJ_USER: |
854 | case AUDIT_OBJ_ROLE: |
855 | case AUDIT_OBJ_TYPE: |
856 | case AUDIT_OBJ_LEV_LOW: |
857 | case AUDIT_OBJ_LEV_HIGH: |
858 | err = audit_dupe_lsm_field(&new->fields[i], |
859 | &old->fields[i]); |
860 | break; |
861 | case AUDIT_FILTERKEY: |
862 | fk = kstrdup(old->filterkey, GFP_KERNEL); |
863 | if (unlikely(!fk)) |
864 | err = -ENOMEM; |
865 | else |
866 | new->filterkey = fk; |
867 | } |
868 | if (err) { |
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. */ |
884 | static 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 | |
915 | out: |
916 | return found; |
917 | } |
918 | |
919 | static u64 prio_low = ~0ULL/2; |
920 | static u64 prio_high = ~0ULL/2 - 1; |
921 | |
922 | /* Add rule to given filterlist if not a duplicate. */ |
923 | static 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; |
930 | #ifdef CONFIG_AUDITSYSCALL |
931 | int dont_count = 0; |
932 | |
933 | /* If either of these, don't count towards total */ |
934 | if (entry->rule.listnr == AUDIT_FILTER_USER || |
935 | entry->rule.listnr == AUDIT_FILTER_TYPE) |
936 | dont_count = 1; |
937 | #endif |
938 | |
939 | mutex_lock(&audit_filter_mutex); |
940 | e = audit_find_rule(entry, &list); |
941 | if (e) { |
942 | mutex_unlock(&audit_filter_mutex); |
943 | err = -EEXIST; |
944 | /* normally audit_add_tree_rule() will free it on failure */ |
945 | if (tree) |
946 | audit_put_tree(tree); |
947 | goto error; |
948 | } |
949 | |
950 | if (watch) { |
951 | /* audit_filter_mutex is dropped and re-taken during this call */ |
952 | err = audit_add_watch(&entry->rule, &list); |
953 | if (err) { |
954 | mutex_unlock(&audit_filter_mutex); |
955 | goto error; |
956 | } |
957 | } |
958 | if (tree) { |
959 | err = audit_add_tree_rule(&entry->rule); |
960 | if (err) { |
961 | mutex_unlock(&audit_filter_mutex); |
962 | goto error; |
963 | } |
964 | } |
965 | |
966 | entry->rule.prio = ~0ULL; |
967 | if (entry->rule.listnr == AUDIT_FILTER_EXIT) { |
968 | if (entry->rule.flags & AUDIT_FILTER_PREPEND) |
969 | entry->rule.prio = ++prio_high; |
970 | else |
971 | entry->rule.prio = --prio_low; |
972 | } |
973 | |
974 | if (entry->rule.flags & AUDIT_FILTER_PREPEND) { |
975 | list_add(&entry->rule.list, |
976 | &audit_rules_list[entry->rule.listnr]); |
977 | list_add_rcu(&entry->list, list); |
978 | entry->rule.flags &= ~AUDIT_FILTER_PREPEND; |
979 | } else { |
980 | list_add_tail(&entry->rule.list, |
981 | &audit_rules_list[entry->rule.listnr]); |
982 | list_add_tail_rcu(&entry->list, list); |
983 | } |
984 | #ifdef CONFIG_AUDITSYSCALL |
985 | if (!dont_count) |
986 | audit_n_rules++; |
987 | |
988 | if (!audit_match_signal(entry)) |
989 | audit_signals++; |
990 | #endif |
991 | mutex_unlock(&audit_filter_mutex); |
992 | |
993 | return 0; |
994 | |
995 | error: |
996 | if (watch) |
997 | audit_put_watch(watch); /* tmp watch, matches initial get */ |
998 | return err; |
999 | } |
1000 | |
1001 | /* Remove an existing rule from filterlist. */ |
1002 | static inline int audit_del_rule(struct audit_entry *entry) |
1003 | { |
1004 | struct audit_entry *e; |
1005 | struct audit_watch *watch = entry->rule.watch; |
1006 | struct audit_tree *tree = entry->rule.tree; |
1007 | struct list_head *list; |
1008 | int ret = 0; |
1009 | #ifdef CONFIG_AUDITSYSCALL |
1010 | int dont_count = 0; |
1011 | |
1012 | /* If either of these, don't count towards total */ |
1013 | if (entry->rule.listnr == AUDIT_FILTER_USER || |
1014 | entry->rule.listnr == AUDIT_FILTER_TYPE) |
1015 | dont_count = 1; |
1016 | #endif |
1017 | |
1018 | mutex_lock(&audit_filter_mutex); |
1019 | e = audit_find_rule(entry, &list); |
1020 | if (!e) { |
1021 | mutex_unlock(&audit_filter_mutex); |
1022 | ret = -ENOENT; |
1023 | goto out; |
1024 | } |
1025 | |
1026 | if (e->rule.watch) |
1027 | audit_remove_watch_rule(&e->rule); |
1028 | |
1029 | if (e->rule.tree) |
1030 | audit_remove_tree_rule(&e->rule); |
1031 | |
1032 | list_del_rcu(&e->list); |
1033 | list_del(&e->rule.list); |
1034 | call_rcu(&e->rcu, audit_free_rule_rcu); |
1035 | |
1036 | #ifdef CONFIG_AUDITSYSCALL |
1037 | if (!dont_count) |
1038 | audit_n_rules--; |
1039 | |
1040 | if (!audit_match_signal(entry)) |
1041 | audit_signals--; |
1042 | #endif |
1043 | mutex_unlock(&audit_filter_mutex); |
1044 | |
1045 | out: |
1046 | if (watch) |
1047 | audit_put_watch(watch); /* match initial get */ |
1048 | if (tree) |
1049 | audit_put_tree(tree); /* that's the temporary one */ |
1050 | |
1051 | return ret; |
1052 | } |
1053 | |
1054 | /* List rules using struct audit_rule. Exists for backward |
1055 | * compatibility with userspace. */ |
1056 | static void audit_list(int pid, int seq, struct sk_buff_head *q) |
1057 | { |
1058 | struct sk_buff *skb; |
1059 | struct audit_krule *r; |
1060 | int i; |
1061 | |
1062 | /* This is a blocking read, so use audit_filter_mutex instead of rcu |
1063 | * iterator to sync with list writers. */ |
1064 | for (i=0; i<AUDIT_NR_FILTERS; i++) { |
1065 | list_for_each_entry(r, &audit_rules_list[i], list) { |
1066 | struct audit_rule *rule; |
1067 | |
1068 | rule = audit_krule_to_rule(r); |
1069 | if (unlikely(!rule)) |
1070 | break; |
1071 | skb = audit_make_reply(pid, seq, AUDIT_LIST, 0, 1, |
1072 | rule, sizeof(*rule)); |
1073 | if (skb) |
1074 | skb_queue_tail(q, skb); |
1075 | kfree(rule); |
1076 | } |
1077 | } |
1078 | skb = audit_make_reply(pid, seq, AUDIT_LIST, 1, 1, NULL, 0); |
1079 | if (skb) |
1080 | skb_queue_tail(q, skb); |
1081 | } |
1082 | |
1083 | /* List rules using struct audit_rule_data. */ |
1084 | static void audit_list_rules(int pid, int seq, struct sk_buff_head *q) |
1085 | { |
1086 | struct sk_buff *skb; |
1087 | struct audit_krule *r; |
1088 | int i; |
1089 | |
1090 | /* This is a blocking read, so use audit_filter_mutex instead of rcu |
1091 | * iterator to sync with list writers. */ |
1092 | for (i=0; i<AUDIT_NR_FILTERS; i++) { |
1093 | list_for_each_entry(r, &audit_rules_list[i], list) { |
1094 | struct audit_rule_data *data; |
1095 | |
1096 | data = audit_krule_to_data(r); |
1097 | if (unlikely(!data)) |
1098 | break; |
1099 | skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 0, 1, |
1100 | data, sizeof(*data) + data->buflen); |
1101 | if (skb) |
1102 | skb_queue_tail(q, skb); |
1103 | kfree(data); |
1104 | } |
1105 | } |
1106 | skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 1, 1, NULL, 0); |
1107 | if (skb) |
1108 | skb_queue_tail(q, skb); |
1109 | } |
1110 | |
1111 | /* Log rule additions and removals */ |
1112 | static void audit_log_rule_change(kuid_t loginuid, u32 sessionid, u32 sid, |
1113 | char *action, struct audit_krule *rule, |
1114 | int res) |
1115 | { |
1116 | struct audit_buffer *ab; |
1117 | |
1118 | if (!audit_enabled) |
1119 | return; |
1120 | |
1121 | ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE); |
1122 | if (!ab) |
1123 | return; |
1124 | audit_log_format(ab, "auid=%u ses=%u", |
1125 | from_kuid(&init_user_ns, loginuid), sessionid); |
1126 | if (sid) { |
1127 | char *ctx = NULL; |
1128 | u32 len; |
1129 | if (security_secid_to_secctx(sid, &ctx, &len)) |
1130 | audit_log_format(ab, " ssid=%u", sid); |
1131 | else { |
1132 | audit_log_format(ab, " subj=%s", ctx); |
1133 | security_release_secctx(ctx, len); |
1134 | } |
1135 | } |
1136 | audit_log_format(ab, " op="); |
1137 | audit_log_string(ab, action); |
1138 | audit_log_key(ab, rule->filterkey); |
1139 | audit_log_format(ab, " list=%d res=%d", rule->listnr, res); |
1140 | audit_log_end(ab); |
1141 | } |
1142 | |
1143 | /** |
1144 | * audit_receive_filter - apply all rules to the specified message type |
1145 | * @type: audit message type |
1146 | * @pid: target pid for netlink audit messages |
1147 | * @seq: netlink audit message sequence (serial) number |
1148 | * @data: payload data |
1149 | * @datasz: size of payload data |
1150 | * @loginuid: loginuid of sender |
1151 | * @sessionid: sessionid for netlink audit message |
1152 | * @sid: SE Linux Security ID of sender |
1153 | */ |
1154 | int audit_receive_filter(int type, int pid, int seq, void *data, |
1155 | size_t datasz, kuid_t loginuid, u32 sessionid, u32 sid) |
1156 | { |
1157 | struct task_struct *tsk; |
1158 | struct audit_netlink_list *dest; |
1159 | int err = 0; |
1160 | struct audit_entry *entry; |
1161 | |
1162 | switch (type) { |
1163 | case AUDIT_LIST: |
1164 | case AUDIT_LIST_RULES: |
1165 | /* We can't just spew out the rules here because we might fill |
1166 | * the available socket buffer space and deadlock waiting for |
1167 | * auditctl to read from it... which isn't ever going to |
1168 | * happen if we're actually running in the context of auditctl |
1169 | * trying to _send_ the stuff */ |
1170 | |
1171 | dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL); |
1172 | if (!dest) |
1173 | return -ENOMEM; |
1174 | dest->pid = pid; |
1175 | skb_queue_head_init(&dest->q); |
1176 | |
1177 | mutex_lock(&audit_filter_mutex); |
1178 | if (type == AUDIT_LIST) |
1179 | audit_list(pid, seq, &dest->q); |
1180 | else |
1181 | audit_list_rules(pid, seq, &dest->q); |
1182 | mutex_unlock(&audit_filter_mutex); |
1183 | |
1184 | tsk = kthread_run(audit_send_list, dest, "audit_send_list"); |
1185 | if (IS_ERR(tsk)) { |
1186 | skb_queue_purge(&dest->q); |
1187 | kfree(dest); |
1188 | err = PTR_ERR(tsk); |
1189 | } |
1190 | break; |
1191 | case AUDIT_ADD: |
1192 | case AUDIT_ADD_RULE: |
1193 | if (type == AUDIT_ADD) |
1194 | entry = audit_rule_to_entry(data); |
1195 | else |
1196 | entry = audit_data_to_entry(data, datasz); |
1197 | if (IS_ERR(entry)) |
1198 | return PTR_ERR(entry); |
1199 | |
1200 | err = audit_add_rule(entry); |
1201 | audit_log_rule_change(loginuid, sessionid, sid, "add rule", |
1202 | &entry->rule, !err); |
1203 | |
1204 | if (err) |
1205 | audit_free_rule(entry); |
1206 | break; |
1207 | case AUDIT_DEL: |
1208 | case AUDIT_DEL_RULE: |
1209 | if (type == AUDIT_DEL) |
1210 | entry = audit_rule_to_entry(data); |
1211 | else |
1212 | entry = audit_data_to_entry(data, datasz); |
1213 | if (IS_ERR(entry)) |
1214 | return PTR_ERR(entry); |
1215 | |
1216 | err = audit_del_rule(entry); |
1217 | audit_log_rule_change(loginuid, sessionid, sid, "remove rule", |
1218 | &entry->rule, !err); |
1219 | |
1220 | audit_free_rule(entry); |
1221 | break; |
1222 | default: |
1223 | return -EINVAL; |
1224 | } |
1225 | |
1226 | return err; |
1227 | } |
1228 | |
1229 | int audit_comparator(u32 left, u32 op, u32 right) |
1230 | { |
1231 | switch (op) { |
1232 | case Audit_equal: |
1233 | return (left == right); |
1234 | case Audit_not_equal: |
1235 | return (left != right); |
1236 | case Audit_lt: |
1237 | return (left < right); |
1238 | case Audit_le: |
1239 | return (left <= right); |
1240 | case Audit_gt: |
1241 | return (left > right); |
1242 | case Audit_ge: |
1243 | return (left >= right); |
1244 | case Audit_bitmask: |
1245 | return (left & right); |
1246 | case Audit_bittest: |
1247 | return ((left & right) == right); |
1248 | default: |
1249 | BUG(); |
1250 | return 0; |
1251 | } |
1252 | } |
1253 | |
1254 | int audit_uid_comparator(kuid_t left, u32 op, kuid_t right) |
1255 | { |
1256 | switch (op) { |
1257 | case Audit_equal: |
1258 | return uid_eq(left, right); |
1259 | case Audit_not_equal: |
1260 | return !uid_eq(left, right); |
1261 | case Audit_lt: |
1262 | return uid_lt(left, right); |
1263 | case Audit_le: |
1264 | return uid_lte(left, right); |
1265 | case Audit_gt: |
1266 | return uid_gt(left, right); |
1267 | case Audit_ge: |
1268 | return uid_gte(left, right); |
1269 | case Audit_bitmask: |
1270 | case Audit_bittest: |
1271 | default: |
1272 | BUG(); |
1273 | return 0; |
1274 | } |
1275 | } |
1276 | |
1277 | int audit_gid_comparator(kgid_t left, u32 op, kgid_t right) |
1278 | { |
1279 | switch (op) { |
1280 | case Audit_equal: |
1281 | return gid_eq(left, right); |
1282 | case Audit_not_equal: |
1283 | return !gid_eq(left, right); |
1284 | case Audit_lt: |
1285 | return gid_lt(left, right); |
1286 | case Audit_le: |
1287 | return gid_lte(left, right); |
1288 | case Audit_gt: |
1289 | return gid_gt(left, right); |
1290 | case Audit_ge: |
1291 | return gid_gte(left, right); |
1292 | case Audit_bitmask: |
1293 | case Audit_bittest: |
1294 | default: |
1295 | BUG(); |
1296 | return 0; |
1297 | } |
1298 | } |
1299 | |
1300 | /** |
1301 | * parent_len - find the length of the parent portion of a pathname |
1302 | * @path: pathname of which to determine length |
1303 | */ |
1304 | int parent_len(const char *path) |
1305 | { |
1306 | int plen; |
1307 | const char *p; |
1308 | |
1309 | plen = strlen(path); |
1310 | |
1311 | if (plen == 0) |
1312 | return plen; |
1313 | |
1314 | /* disregard trailing slashes */ |
1315 | p = path + plen - 1; |
1316 | while ((*p == '/') && (p > path)) |
1317 | p--; |
1318 | |
1319 | /* walk backward until we find the next slash or hit beginning */ |
1320 | while ((*p != '/') && (p > path)) |
1321 | p--; |
1322 | |
1323 | /* did we find a slash? Then increment to include it in path */ |
1324 | if (*p == '/') |
1325 | p++; |
1326 | |
1327 | return p - path; |
1328 | } |
1329 | |
1330 | /** |
1331 | * audit_compare_dname_path - compare given dentry name with last component in |
1332 | * given path. Return of 0 indicates a match. |
1333 | * @dname: dentry name that we're comparing |
1334 | * @path: full pathname that we're comparing |
1335 | * @parentlen: length of the parent if known. Passing in AUDIT_NAME_FULL |
1336 | * here indicates that we must compute this value. |
1337 | */ |
1338 | int audit_compare_dname_path(const char *dname, const char *path, int parentlen) |
1339 | { |
1340 | int dlen, pathlen; |
1341 | const char *p; |
1342 | |
1343 | dlen = strlen(dname); |
1344 | pathlen = strlen(path); |
1345 | if (pathlen < dlen) |
1346 | return 1; |
1347 | |
1348 | parentlen = parentlen == AUDIT_NAME_FULL ? parent_len(path) : parentlen; |
1349 | if (pathlen - parentlen != dlen) |
1350 | return 1; |
1351 | |
1352 | p = path + parentlen; |
1353 | |
1354 | return strncmp(p, dname, dlen); |
1355 | } |
1356 | |
1357 | static int audit_filter_user_rules(struct audit_krule *rule, |
1358 | enum audit_state *state) |
1359 | { |
1360 | int i; |
1361 | |
1362 | for (i = 0; i < rule->field_count; i++) { |
1363 | struct audit_field *f = &rule->fields[i]; |
1364 | int result = 0; |
1365 | u32 sid; |
1366 | |
1367 | switch (f->type) { |
1368 | case AUDIT_PID: |
1369 | result = audit_comparator(task_pid_vnr(current), f->op, f->val); |
1370 | break; |
1371 | case AUDIT_UID: |
1372 | result = audit_uid_comparator(current_uid(), f->op, f->uid); |
1373 | break; |
1374 | case AUDIT_GID: |
1375 | result = audit_gid_comparator(current_gid(), f->op, f->gid); |
1376 | break; |
1377 | case AUDIT_LOGINUID: |
1378 | result = audit_uid_comparator(audit_get_loginuid(current), |
1379 | f->op, f->uid); |
1380 | break; |
1381 | case AUDIT_SUBJ_USER: |
1382 | case AUDIT_SUBJ_ROLE: |
1383 | case AUDIT_SUBJ_TYPE: |
1384 | case AUDIT_SUBJ_SEN: |
1385 | case AUDIT_SUBJ_CLR: |
1386 | if (f->lsm_rule) { |
1387 | security_task_getsecid(current, &sid); |
1388 | result = security_audit_rule_match(sid, |
1389 | f->type, |
1390 | f->op, |
1391 | f->lsm_rule, |
1392 | NULL); |
1393 | } |
1394 | break; |
1395 | } |
1396 | |
1397 | if (!result) |
1398 | return 0; |
1399 | } |
1400 | switch (rule->action) { |
1401 | case AUDIT_NEVER: *state = AUDIT_DISABLED; break; |
1402 | case AUDIT_ALWAYS: *state = AUDIT_RECORD_CONTEXT; break; |
1403 | } |
1404 | return 1; |
1405 | } |
1406 | |
1407 | int audit_filter_user(void) |
1408 | { |
1409 | enum audit_state state = AUDIT_DISABLED; |
1410 | struct audit_entry *e; |
1411 | int ret = 1; |
1412 | |
1413 | rcu_read_lock(); |
1414 | list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_USER], list) { |
1415 | if (audit_filter_user_rules(&e->rule, &state)) { |
1416 | if (state == AUDIT_DISABLED) |
1417 | ret = 0; |
1418 | break; |
1419 | } |
1420 | } |
1421 | rcu_read_unlock(); |
1422 | |
1423 | return ret; /* Audit by default */ |
1424 | } |
1425 | |
1426 | int audit_filter_type(int type) |
1427 | { |
1428 | struct audit_entry *e; |
1429 | int result = 0; |
1430 | |
1431 | rcu_read_lock(); |
1432 | if (list_empty(&audit_filter_list[AUDIT_FILTER_TYPE])) |
1433 | goto unlock_and_return; |
1434 | |
1435 | list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_TYPE], |
1436 | list) { |
1437 | int i; |
1438 | for (i = 0; i < e->rule.field_count; i++) { |
1439 | struct audit_field *f = &e->rule.fields[i]; |
1440 | if (f->type == AUDIT_MSGTYPE) { |
1441 | result = audit_comparator(type, f->op, f->val); |
1442 | if (!result) |
1443 | break; |
1444 | } |
1445 | } |
1446 | if (result) |
1447 | goto unlock_and_return; |
1448 | } |
1449 | unlock_and_return: |
1450 | rcu_read_unlock(); |
1451 | return result; |
1452 | } |
1453 | |
1454 | static int update_lsm_rule(struct audit_krule *r) |
1455 | { |
1456 | struct audit_entry *entry = container_of(r, struct audit_entry, rule); |
1457 | struct audit_entry *nentry; |
1458 | int err = 0; |
1459 | |
1460 | if (!security_audit_rule_known(r)) |
1461 | return 0; |
1462 | |
1463 | nentry = audit_dupe_rule(r); |
1464 | if (IS_ERR(nentry)) { |
1465 | /* save the first error encountered for the |
1466 | * return value */ |
1467 | err = PTR_ERR(nentry); |
1468 | audit_panic("error updating LSM filters"); |
1469 | if (r->watch) |
1470 | list_del(&r->rlist); |
1471 | list_del_rcu(&entry->list); |
1472 | list_del(&r->list); |
1473 | } else { |
1474 | if (r->watch || r->tree) |
1475 | list_replace_init(&r->rlist, &nentry->rule.rlist); |
1476 | list_replace_rcu(&entry->list, &nentry->list); |
1477 | list_replace(&r->list, &nentry->rule.list); |
1478 | } |
1479 | call_rcu(&entry->rcu, audit_free_rule_rcu); |
1480 | |
1481 | return err; |
1482 | } |
1483 | |
1484 | /* This function will re-initialize the lsm_rule field of all applicable rules. |
1485 | * It will traverse the filter lists serarching for rules that contain LSM |
1486 | * specific filter fields. When such a rule is found, it is copied, the |
1487 | * LSM field is re-initialized, and the old rule is replaced with the |
1488 | * updated rule. */ |
1489 | int audit_update_lsm_rules(void) |
1490 | { |
1491 | struct audit_krule *r, *n; |
1492 | int i, err = 0; |
1493 | |
1494 | /* audit_filter_mutex synchronizes the writers */ |
1495 | mutex_lock(&audit_filter_mutex); |
1496 | |
1497 | for (i = 0; i < AUDIT_NR_FILTERS; i++) { |
1498 | list_for_each_entry_safe(r, n, &audit_rules_list[i], list) { |
1499 | int res = update_lsm_rule(r); |
1500 | if (!err) |
1501 | err = res; |
1502 | } |
1503 | } |
1504 | mutex_unlock(&audit_filter_mutex); |
1505 | |
1506 | return err; |
1507 | } |
1508 |
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Tags:
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od-2011-09-18
v2.6.34-rc5
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