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