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85c8721f | 1 | /* auditsc.c -- System-call auditing support |
1da177e4 LT |
2 | * Handles all system-call specific auditing features. |
3 | * | |
4 | * Copyright 2003-2004 Red Hat Inc., Durham, North Carolina. | |
5 | * All Rights Reserved. | |
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 | * Written by Rickard E. (Rik) Faith <faith@redhat.com> | |
22 | * | |
23 | * Many of the ideas implemented here are from Stephen C. Tweedie, | |
24 | * especially the idea of avoiding a copy by using getname. | |
25 | * | |
26 | * The method for actual interception of syscall entry and exit (not in | |
27 | * this file -- see entry.S) is based on a GPL'd patch written by | |
28 | * okir@suse.de and Copyright 2003 SuSE Linux AG. | |
29 | * | |
30 | */ | |
31 | ||
32 | #include <linux/init.h> | |
33 | #include <asm/atomic.h> | |
34 | #include <asm/types.h> | |
35 | #include <linux/mm.h> | |
36 | #include <linux/module.h> | |
3ec3b2fb | 37 | #include <linux/socket.h> |
1da177e4 LT |
38 | #include <linux/audit.h> |
39 | #include <linux/personality.h> | |
40 | #include <linux/time.h> | |
41 | #include <asm/unistd.h> | |
42 | ||
43 | /* 0 = no checking | |
44 | 1 = put_count checking | |
45 | 2 = verbose put_count checking | |
46 | */ | |
47 | #define AUDIT_DEBUG 0 | |
48 | ||
49 | /* No syscall auditing will take place unless audit_enabled != 0. */ | |
50 | extern int audit_enabled; | |
51 | ||
52 | /* AUDIT_NAMES is the number of slots we reserve in the audit_context | |
53 | * for saving names from getname(). */ | |
54 | #define AUDIT_NAMES 20 | |
55 | ||
56 | /* AUDIT_NAMES_RESERVED is the number of slots we reserve in the | |
57 | * audit_context from being used for nameless inodes from | |
58 | * path_lookup. */ | |
59 | #define AUDIT_NAMES_RESERVED 7 | |
60 | ||
61 | /* At task start time, the audit_state is set in the audit_context using | |
62 | a per-task filter. At syscall entry, the audit_state is augmented by | |
63 | the syscall filter. */ | |
64 | enum audit_state { | |
65 | AUDIT_DISABLED, /* Do not create per-task audit_context. | |
66 | * No syscall-specific audit records can | |
67 | * be generated. */ | |
68 | AUDIT_SETUP_CONTEXT, /* Create the per-task audit_context, | |
69 | * but don't necessarily fill it in at | |
70 | * syscall entry time (i.e., filter | |
71 | * instead). */ | |
72 | AUDIT_BUILD_CONTEXT, /* Create the per-task audit_context, | |
73 | * and always fill it in at syscall | |
74 | * entry time. This makes a full | |
75 | * syscall record available if some | |
76 | * other part of the kernel decides it | |
77 | * should be recorded. */ | |
78 | AUDIT_RECORD_CONTEXT /* Create the per-task audit_context, | |
79 | * always fill it in at syscall entry | |
80 | * time, and always write out the audit | |
81 | * record at syscall exit time. */ | |
82 | }; | |
83 | ||
84 | /* When fs/namei.c:getname() is called, we store the pointer in name and | |
85 | * we don't let putname() free it (instead we free all of the saved | |
86 | * pointers at syscall exit time). | |
87 | * | |
88 | * Further, in fs/namei.c:path_lookup() we store the inode and device. */ | |
89 | struct audit_names { | |
90 | const char *name; | |
91 | unsigned long ino; | |
92 | dev_t dev; | |
93 | umode_t mode; | |
94 | uid_t uid; | |
95 | gid_t gid; | |
96 | dev_t rdev; | |
97 | }; | |
98 | ||
99 | struct audit_aux_data { | |
100 | struct audit_aux_data *next; | |
101 | int type; | |
102 | }; | |
103 | ||
104 | #define AUDIT_AUX_IPCPERM 0 | |
105 | ||
106 | struct audit_aux_data_ipcctl { | |
107 | struct audit_aux_data d; | |
108 | struct ipc_perm p; | |
109 | unsigned long qbytes; | |
110 | uid_t uid; | |
111 | gid_t gid; | |
112 | mode_t mode; | |
113 | }; | |
114 | ||
3ec3b2fb DW |
115 | struct audit_aux_data_socketcall { |
116 | struct audit_aux_data d; | |
117 | int nargs; | |
118 | unsigned long args[0]; | |
119 | }; | |
120 | ||
121 | struct audit_aux_data_sockaddr { | |
122 | struct audit_aux_data d; | |
123 | int len; | |
124 | char a[0]; | |
125 | }; | |
126 | ||
1da177e4 LT |
127 | |
128 | /* The per-task audit context. */ | |
129 | struct audit_context { | |
130 | int in_syscall; /* 1 if task is in a syscall */ | |
131 | enum audit_state state; | |
132 | unsigned int serial; /* serial number for record */ | |
133 | struct timespec ctime; /* time of syscall entry */ | |
134 | uid_t loginuid; /* login uid (identity) */ | |
135 | int major; /* syscall number */ | |
136 | unsigned long argv[4]; /* syscall arguments */ | |
137 | int return_valid; /* return code is valid */ | |
2fd6f58b | 138 | long return_code;/* syscall return code */ |
1da177e4 LT |
139 | int auditable; /* 1 if record should be written */ |
140 | int name_count; | |
141 | struct audit_names names[AUDIT_NAMES]; | |
142 | struct audit_context *previous; /* For nested syscalls */ | |
143 | struct audit_aux_data *aux; | |
144 | ||
145 | /* Save things to print about task_struct */ | |
146 | pid_t pid; | |
147 | uid_t uid, euid, suid, fsuid; | |
148 | gid_t gid, egid, sgid, fsgid; | |
149 | unsigned long personality; | |
2fd6f58b | 150 | int arch; |
1da177e4 LT |
151 | |
152 | #if AUDIT_DEBUG | |
153 | int put_count; | |
154 | int ino_count; | |
155 | #endif | |
156 | }; | |
157 | ||
158 | /* Public API */ | |
159 | /* There are three lists of rules -- one to search at task creation | |
160 | * time, one to search at syscall entry time, and another to search at | |
161 | * syscall exit time. */ | |
162 | static LIST_HEAD(audit_tsklist); | |
163 | static LIST_HEAD(audit_entlist); | |
164 | static LIST_HEAD(audit_extlist); | |
165 | ||
166 | struct audit_entry { | |
167 | struct list_head list; | |
168 | struct rcu_head rcu; | |
169 | struct audit_rule rule; | |
170 | }; | |
171 | ||
7ca00264 DW |
172 | extern int audit_pid; |
173 | ||
1da177e4 LT |
174 | /* Check to see if two rules are identical. It is called from |
175 | * audit_del_rule during AUDIT_DEL. */ | |
176 | static int audit_compare_rule(struct audit_rule *a, struct audit_rule *b) | |
177 | { | |
178 | int i; | |
179 | ||
180 | if (a->flags != b->flags) | |
181 | return 1; | |
182 | ||
183 | if (a->action != b->action) | |
184 | return 1; | |
185 | ||
186 | if (a->field_count != b->field_count) | |
187 | return 1; | |
188 | ||
189 | for (i = 0; i < a->field_count; i++) { | |
190 | if (a->fields[i] != b->fields[i] | |
191 | || a->values[i] != b->values[i]) | |
192 | return 1; | |
193 | } | |
194 | ||
195 | for (i = 0; i < AUDIT_BITMASK_SIZE; i++) | |
196 | if (a->mask[i] != b->mask[i]) | |
197 | return 1; | |
198 | ||
199 | return 0; | |
200 | } | |
201 | ||
202 | /* Note that audit_add_rule and audit_del_rule are called via | |
203 | * audit_receive() in audit.c, and are protected by | |
204 | * audit_netlink_sem. */ | |
205 | static inline int audit_add_rule(struct audit_entry *entry, | |
206 | struct list_head *list) | |
207 | { | |
208 | if (entry->rule.flags & AUDIT_PREPEND) { | |
209 | entry->rule.flags &= ~AUDIT_PREPEND; | |
210 | list_add_rcu(&entry->list, list); | |
211 | } else { | |
212 | list_add_tail_rcu(&entry->list, list); | |
213 | } | |
214 | return 0; | |
215 | } | |
216 | ||
217 | static void audit_free_rule(struct rcu_head *head) | |
218 | { | |
219 | struct audit_entry *e = container_of(head, struct audit_entry, rcu); | |
220 | kfree(e); | |
221 | } | |
222 | ||
223 | /* Note that audit_add_rule and audit_del_rule are called via | |
224 | * audit_receive() in audit.c, and are protected by | |
225 | * audit_netlink_sem. */ | |
226 | static inline int audit_del_rule(struct audit_rule *rule, | |
227 | struct list_head *list) | |
228 | { | |
229 | struct audit_entry *e; | |
230 | ||
231 | /* Do not use the _rcu iterator here, since this is the only | |
232 | * deletion routine. */ | |
233 | list_for_each_entry(e, list, list) { | |
234 | if (!audit_compare_rule(rule, &e->rule)) { | |
235 | list_del_rcu(&e->list); | |
236 | call_rcu(&e->rcu, audit_free_rule); | |
237 | return 0; | |
238 | } | |
239 | } | |
240 | return -EFAULT; /* No matching rule */ | |
241 | } | |
242 | ||
1da177e4 LT |
243 | /* Copy rule from user-space to kernel-space. Called during |
244 | * AUDIT_ADD. */ | |
245 | static int audit_copy_rule(struct audit_rule *d, struct audit_rule *s) | |
246 | { | |
247 | int i; | |
248 | ||
249 | if (s->action != AUDIT_NEVER | |
250 | && s->action != AUDIT_POSSIBLE | |
251 | && s->action != AUDIT_ALWAYS) | |
252 | return -1; | |
253 | if (s->field_count < 0 || s->field_count > AUDIT_MAX_FIELDS) | |
254 | return -1; | |
255 | ||
256 | d->flags = s->flags; | |
257 | d->action = s->action; | |
258 | d->field_count = s->field_count; | |
259 | for (i = 0; i < d->field_count; i++) { | |
260 | d->fields[i] = s->fields[i]; | |
261 | d->values[i] = s->values[i]; | |
262 | } | |
263 | for (i = 0; i < AUDIT_BITMASK_SIZE; i++) d->mask[i] = s->mask[i]; | |
264 | return 0; | |
265 | } | |
266 | ||
c94c257c SH |
267 | int audit_receive_filter(int type, int pid, int uid, int seq, void *data, |
268 | uid_t loginuid) | |
1da177e4 LT |
269 | { |
270 | u32 flags; | |
271 | struct audit_entry *entry; | |
272 | int err = 0; | |
273 | ||
274 | switch (type) { | |
275 | case AUDIT_LIST: | |
276 | /* The *_rcu iterators not needed here because we are | |
277 | always called with audit_netlink_sem held. */ | |
278 | list_for_each_entry(entry, &audit_tsklist, list) | |
279 | audit_send_reply(pid, seq, AUDIT_LIST, 0, 1, | |
280 | &entry->rule, sizeof(entry->rule)); | |
281 | list_for_each_entry(entry, &audit_entlist, list) | |
282 | audit_send_reply(pid, seq, AUDIT_LIST, 0, 1, | |
283 | &entry->rule, sizeof(entry->rule)); | |
284 | list_for_each_entry(entry, &audit_extlist, list) | |
285 | audit_send_reply(pid, seq, AUDIT_LIST, 0, 1, | |
286 | &entry->rule, sizeof(entry->rule)); | |
287 | audit_send_reply(pid, seq, AUDIT_LIST, 1, 1, NULL, 0); | |
288 | break; | |
289 | case AUDIT_ADD: | |
290 | if (!(entry = kmalloc(sizeof(*entry), GFP_KERNEL))) | |
291 | return -ENOMEM; | |
292 | if (audit_copy_rule(&entry->rule, data)) { | |
293 | kfree(entry); | |
294 | return -EINVAL; | |
295 | } | |
296 | flags = entry->rule.flags; | |
297 | if (!err && (flags & AUDIT_PER_TASK)) | |
298 | err = audit_add_rule(entry, &audit_tsklist); | |
299 | if (!err && (flags & AUDIT_AT_ENTRY)) | |
300 | err = audit_add_rule(entry, &audit_entlist); | |
301 | if (!err && (flags & AUDIT_AT_EXIT)) | |
302 | err = audit_add_rule(entry, &audit_extlist); | |
c0404993 SG |
303 | audit_log(NULL, AUDIT_CONFIG_CHANGE, |
304 | "auid %u added an audit rule\n", loginuid); | |
1da177e4 LT |
305 | break; |
306 | case AUDIT_DEL: | |
307 | flags =((struct audit_rule *)data)->flags; | |
308 | if (!err && (flags & AUDIT_PER_TASK)) | |
309 | err = audit_del_rule(data, &audit_tsklist); | |
310 | if (!err && (flags & AUDIT_AT_ENTRY)) | |
311 | err = audit_del_rule(data, &audit_entlist); | |
312 | if (!err && (flags & AUDIT_AT_EXIT)) | |
313 | err = audit_del_rule(data, &audit_extlist); | |
c0404993 SG |
314 | audit_log(NULL, AUDIT_CONFIG_CHANGE, |
315 | "auid %u removed an audit rule\n", loginuid); | |
1da177e4 LT |
316 | break; |
317 | default: | |
318 | return -EINVAL; | |
319 | } | |
320 | ||
321 | return err; | |
322 | } | |
1da177e4 LT |
323 | |
324 | /* Compare a task_struct with an audit_rule. Return 1 on match, 0 | |
325 | * otherwise. */ | |
326 | static int audit_filter_rules(struct task_struct *tsk, | |
327 | struct audit_rule *rule, | |
328 | struct audit_context *ctx, | |
329 | enum audit_state *state) | |
330 | { | |
331 | int i, j; | |
332 | ||
333 | for (i = 0; i < rule->field_count; i++) { | |
334 | u32 field = rule->fields[i] & ~AUDIT_NEGATE; | |
335 | u32 value = rule->values[i]; | |
336 | int result = 0; | |
337 | ||
338 | switch (field) { | |
339 | case AUDIT_PID: | |
340 | result = (tsk->pid == value); | |
341 | break; | |
342 | case AUDIT_UID: | |
343 | result = (tsk->uid == value); | |
344 | break; | |
345 | case AUDIT_EUID: | |
346 | result = (tsk->euid == value); | |
347 | break; | |
348 | case AUDIT_SUID: | |
349 | result = (tsk->suid == value); | |
350 | break; | |
351 | case AUDIT_FSUID: | |
352 | result = (tsk->fsuid == value); | |
353 | break; | |
354 | case AUDIT_GID: | |
355 | result = (tsk->gid == value); | |
356 | break; | |
357 | case AUDIT_EGID: | |
358 | result = (tsk->egid == value); | |
359 | break; | |
360 | case AUDIT_SGID: | |
361 | result = (tsk->sgid == value); | |
362 | break; | |
363 | case AUDIT_FSGID: | |
364 | result = (tsk->fsgid == value); | |
365 | break; | |
366 | case AUDIT_PERS: | |
367 | result = (tsk->personality == value); | |
368 | break; | |
2fd6f58b DW |
369 | case AUDIT_ARCH: |
370 | if (ctx) | |
371 | result = (ctx->arch == value); | |
372 | break; | |
1da177e4 LT |
373 | |
374 | case AUDIT_EXIT: | |
375 | if (ctx && ctx->return_valid) | |
376 | result = (ctx->return_code == value); | |
377 | break; | |
378 | case AUDIT_SUCCESS: | |
379 | if (ctx && ctx->return_valid) | |
2fd6f58b | 380 | result = (ctx->return_valid == AUDITSC_SUCCESS); |
1da177e4 LT |
381 | break; |
382 | case AUDIT_DEVMAJOR: | |
383 | if (ctx) { | |
384 | for (j = 0; j < ctx->name_count; j++) { | |
385 | if (MAJOR(ctx->names[j].dev)==value) { | |
386 | ++result; | |
387 | break; | |
388 | } | |
389 | } | |
390 | } | |
391 | break; | |
392 | case AUDIT_DEVMINOR: | |
393 | if (ctx) { | |
394 | for (j = 0; j < ctx->name_count; j++) { | |
395 | if (MINOR(ctx->names[j].dev)==value) { | |
396 | ++result; | |
397 | break; | |
398 | } | |
399 | } | |
400 | } | |
401 | break; | |
402 | case AUDIT_INODE: | |
403 | if (ctx) { | |
404 | for (j = 0; j < ctx->name_count; j++) { | |
405 | if (ctx->names[j].ino == value) { | |
406 | ++result; | |
407 | break; | |
408 | } | |
409 | } | |
410 | } | |
411 | break; | |
412 | case AUDIT_LOGINUID: | |
413 | result = 0; | |
414 | if (ctx) | |
415 | result = (ctx->loginuid == value); | |
416 | break; | |
417 | case AUDIT_ARG0: | |
418 | case AUDIT_ARG1: | |
419 | case AUDIT_ARG2: | |
420 | case AUDIT_ARG3: | |
421 | if (ctx) | |
422 | result = (ctx->argv[field-AUDIT_ARG0]==value); | |
423 | break; | |
424 | } | |
425 | ||
426 | if (rule->fields[i] & AUDIT_NEGATE) | |
427 | result = !result; | |
428 | if (!result) | |
429 | return 0; | |
430 | } | |
431 | switch (rule->action) { | |
432 | case AUDIT_NEVER: *state = AUDIT_DISABLED; break; | |
433 | case AUDIT_POSSIBLE: *state = AUDIT_BUILD_CONTEXT; break; | |
434 | case AUDIT_ALWAYS: *state = AUDIT_RECORD_CONTEXT; break; | |
435 | } | |
436 | return 1; | |
437 | } | |
438 | ||
439 | /* At process creation time, we can determine if system-call auditing is | |
440 | * completely disabled for this task. Since we only have the task | |
441 | * structure at this point, we can only check uid and gid. | |
442 | */ | |
443 | static enum audit_state audit_filter_task(struct task_struct *tsk) | |
444 | { | |
445 | struct audit_entry *e; | |
446 | enum audit_state state; | |
447 | ||
448 | rcu_read_lock(); | |
449 | list_for_each_entry_rcu(e, &audit_tsklist, list) { | |
450 | if (audit_filter_rules(tsk, &e->rule, NULL, &state)) { | |
451 | rcu_read_unlock(); | |
452 | return state; | |
453 | } | |
454 | } | |
455 | rcu_read_unlock(); | |
456 | return AUDIT_BUILD_CONTEXT; | |
457 | } | |
458 | ||
459 | /* At syscall entry and exit time, this filter is called if the | |
460 | * audit_state is not low enough that auditing cannot take place, but is | |
23f32d18 | 461 | * also not high enough that we already know we have to write an audit |
1da177e4 LT |
462 | * record (i.e., the state is AUDIT_SETUP_CONTEXT or AUDIT_BUILD_CONTEXT). |
463 | */ | |
464 | static enum audit_state audit_filter_syscall(struct task_struct *tsk, | |
465 | struct audit_context *ctx, | |
466 | struct list_head *list) | |
467 | { | |
468 | struct audit_entry *e; | |
469 | enum audit_state state; | |
470 | int word = AUDIT_WORD(ctx->major); | |
471 | int bit = AUDIT_BIT(ctx->major); | |
472 | ||
473 | rcu_read_lock(); | |
474 | list_for_each_entry_rcu(e, list, list) { | |
475 | if ((e->rule.mask[word] & bit) == bit | |
476 | && audit_filter_rules(tsk, &e->rule, ctx, &state)) { | |
477 | rcu_read_unlock(); | |
478 | return state; | |
479 | } | |
480 | } | |
481 | rcu_read_unlock(); | |
482 | return AUDIT_BUILD_CONTEXT; | |
483 | } | |
484 | ||
485 | /* This should be called with task_lock() held. */ | |
486 | static inline struct audit_context *audit_get_context(struct task_struct *tsk, | |
487 | int return_valid, | |
488 | int return_code) | |
489 | { | |
490 | struct audit_context *context = tsk->audit_context; | |
491 | ||
492 | if (likely(!context)) | |
493 | return NULL; | |
494 | context->return_valid = return_valid; | |
495 | context->return_code = return_code; | |
496 | ||
497 | if (context->in_syscall && !context->auditable) { | |
498 | enum audit_state state; | |
499 | state = audit_filter_syscall(tsk, context, &audit_extlist); | |
500 | if (state == AUDIT_RECORD_CONTEXT) | |
501 | context->auditable = 1; | |
502 | } | |
503 | ||
504 | context->pid = tsk->pid; | |
505 | context->uid = tsk->uid; | |
506 | context->gid = tsk->gid; | |
507 | context->euid = tsk->euid; | |
508 | context->suid = tsk->suid; | |
509 | context->fsuid = tsk->fsuid; | |
510 | context->egid = tsk->egid; | |
511 | context->sgid = tsk->sgid; | |
512 | context->fsgid = tsk->fsgid; | |
513 | context->personality = tsk->personality; | |
514 | tsk->audit_context = NULL; | |
515 | return context; | |
516 | } | |
517 | ||
518 | static inline void audit_free_names(struct audit_context *context) | |
519 | { | |
520 | int i; | |
521 | ||
522 | #if AUDIT_DEBUG == 2 | |
523 | if (context->auditable | |
524 | ||context->put_count + context->ino_count != context->name_count) { | |
525 | printk(KERN_ERR "audit.c:%d(:%d): major=%d in_syscall=%d" | |
526 | " name_count=%d put_count=%d" | |
527 | " ino_count=%d [NOT freeing]\n", | |
528 | __LINE__, | |
529 | context->serial, context->major, context->in_syscall, | |
530 | context->name_count, context->put_count, | |
531 | context->ino_count); | |
532 | for (i = 0; i < context->name_count; i++) | |
533 | printk(KERN_ERR "names[%d] = %p = %s\n", i, | |
534 | context->names[i].name, | |
535 | context->names[i].name); | |
536 | dump_stack(); | |
537 | return; | |
538 | } | |
539 | #endif | |
540 | #if AUDIT_DEBUG | |
541 | context->put_count = 0; | |
542 | context->ino_count = 0; | |
543 | #endif | |
544 | ||
545 | for (i = 0; i < context->name_count; i++) | |
546 | if (context->names[i].name) | |
547 | __putname(context->names[i].name); | |
548 | context->name_count = 0; | |
549 | } | |
550 | ||
551 | static inline void audit_free_aux(struct audit_context *context) | |
552 | { | |
553 | struct audit_aux_data *aux; | |
554 | ||
555 | while ((aux = context->aux)) { | |
556 | context->aux = aux->next; | |
557 | kfree(aux); | |
558 | } | |
559 | } | |
560 | ||
561 | static inline void audit_zero_context(struct audit_context *context, | |
562 | enum audit_state state) | |
563 | { | |
564 | uid_t loginuid = context->loginuid; | |
565 | ||
566 | memset(context, 0, sizeof(*context)); | |
567 | context->state = state; | |
568 | context->loginuid = loginuid; | |
569 | } | |
570 | ||
571 | static inline struct audit_context *audit_alloc_context(enum audit_state state) | |
572 | { | |
573 | struct audit_context *context; | |
574 | ||
575 | if (!(context = kmalloc(sizeof(*context), GFP_KERNEL))) | |
576 | return NULL; | |
577 | audit_zero_context(context, state); | |
578 | return context; | |
579 | } | |
580 | ||
581 | /* Filter on the task information and allocate a per-task audit context | |
582 | * if necessary. Doing so turns on system call auditing for the | |
583 | * specified task. This is called from copy_process, so no lock is | |
584 | * needed. */ | |
585 | int audit_alloc(struct task_struct *tsk) | |
586 | { | |
587 | struct audit_context *context; | |
588 | enum audit_state state; | |
589 | ||
590 | if (likely(!audit_enabled)) | |
591 | return 0; /* Return if not auditing. */ | |
592 | ||
593 | state = audit_filter_task(tsk); | |
594 | if (likely(state == AUDIT_DISABLED)) | |
595 | return 0; | |
596 | ||
597 | if (!(context = audit_alloc_context(state))) { | |
598 | audit_log_lost("out of memory in audit_alloc"); | |
599 | return -ENOMEM; | |
600 | } | |
601 | ||
602 | /* Preserve login uid */ | |
603 | context->loginuid = -1; | |
604 | if (current->audit_context) | |
605 | context->loginuid = current->audit_context->loginuid; | |
606 | ||
607 | tsk->audit_context = context; | |
608 | set_tsk_thread_flag(tsk, TIF_SYSCALL_AUDIT); | |
609 | return 0; | |
610 | } | |
611 | ||
612 | static inline void audit_free_context(struct audit_context *context) | |
613 | { | |
614 | struct audit_context *previous; | |
615 | int count = 0; | |
616 | ||
617 | do { | |
618 | previous = context->previous; | |
619 | if (previous || (count && count < 10)) { | |
620 | ++count; | |
621 | printk(KERN_ERR "audit(:%d): major=%d name_count=%d:" | |
622 | " freeing multiple contexts (%d)\n", | |
623 | context->serial, context->major, | |
624 | context->name_count, count); | |
625 | } | |
626 | audit_free_names(context); | |
627 | audit_free_aux(context); | |
628 | kfree(context); | |
629 | context = previous; | |
630 | } while (context); | |
631 | if (count >= 10) | |
632 | printk(KERN_ERR "audit: freed %d contexts\n", count); | |
633 | } | |
634 | ||
219f0817 SS |
635 | static void audit_log_task_info(struct audit_buffer *ab) |
636 | { | |
637 | char name[sizeof(current->comm)]; | |
638 | struct mm_struct *mm = current->mm; | |
639 | struct vm_area_struct *vma; | |
640 | ||
641 | get_task_comm(name, current); | |
642 | audit_log_format(ab, " comm=%s", name); | |
643 | ||
644 | if (!mm) | |
645 | return; | |
646 | ||
647 | down_read(&mm->mmap_sem); | |
648 | vma = mm->mmap; | |
649 | while (vma) { | |
650 | if ((vma->vm_flags & VM_EXECUTABLE) && | |
651 | vma->vm_file) { | |
652 | audit_log_d_path(ab, "exe=", | |
653 | vma->vm_file->f_dentry, | |
654 | vma->vm_file->f_vfsmnt); | |
655 | break; | |
656 | } | |
657 | vma = vma->vm_next; | |
658 | } | |
659 | up_read(&mm->mmap_sem); | |
660 | } | |
661 | ||
1da177e4 LT |
662 | static void audit_log_exit(struct audit_context *context) |
663 | { | |
664 | int i; | |
665 | struct audit_buffer *ab; | |
666 | ||
c0404993 | 667 | ab = audit_log_start(context, AUDIT_SYSCALL); |
1da177e4 LT |
668 | if (!ab) |
669 | return; /* audit_panic has been called */ | |
670 | audit_log_format(ab, "syscall=%d", context->major); | |
671 | if (context->personality != PER_LINUX) | |
672 | audit_log_format(ab, " per=%lx", context->personality); | |
2fd6f58b | 673 | audit_log_format(ab, " arch=%x", context->arch); |
1da177e4 | 674 | if (context->return_valid) |
2fd6f58b DW |
675 | audit_log_format(ab, " success=%s exit=%ld", |
676 | (context->return_valid==AUDITSC_SUCCESS)?"yes":"no", | |
677 | context->return_code); | |
1da177e4 LT |
678 | audit_log_format(ab, |
679 | " a0=%lx a1=%lx a2=%lx a3=%lx items=%d" | |
680 | " pid=%d loginuid=%d uid=%d gid=%d" | |
681 | " euid=%d suid=%d fsuid=%d" | |
682 | " egid=%d sgid=%d fsgid=%d", | |
683 | context->argv[0], | |
684 | context->argv[1], | |
685 | context->argv[2], | |
686 | context->argv[3], | |
687 | context->name_count, | |
688 | context->pid, | |
689 | context->loginuid, | |
690 | context->uid, | |
691 | context->gid, | |
692 | context->euid, context->suid, context->fsuid, | |
693 | context->egid, context->sgid, context->fsgid); | |
219f0817 | 694 | audit_log_task_info(ab); |
1da177e4 LT |
695 | audit_log_end(ab); |
696 | while (context->aux) { | |
697 | struct audit_aux_data *aux; | |
698 | ||
c0404993 SG |
699 | aux = context->aux; |
700 | ||
701 | ab = audit_log_start(context, aux->type); | |
1da177e4 LT |
702 | if (!ab) |
703 | continue; /* audit_panic has been called */ | |
704 | ||
1da177e4 | 705 | switch (aux->type) { |
c0404993 | 706 | case AUDIT_IPC: { |
1da177e4 LT |
707 | struct audit_aux_data_ipcctl *axi = (void *)aux; |
708 | audit_log_format(ab, | |
c0404993 | 709 | " qbytes=%lx iuid=%d igid=%d mode=%x", |
1da177e4 | 710 | axi->qbytes, axi->uid, axi->gid, axi->mode); |
3ec3b2fb DW |
711 | break; } |
712 | ||
713 | case AUDIT_SOCKETCALL: { | |
714 | int i; | |
715 | struct audit_aux_data_socketcall *axs = (void *)aux; | |
716 | audit_log_format(ab, "nargs=%d", axs->nargs); | |
717 | for (i=0; i<axs->nargs; i++) | |
718 | audit_log_format(ab, " a%d=%lx", i, axs->args[i]); | |
719 | break; } | |
720 | ||
721 | case AUDIT_SOCKADDR: { | |
722 | struct audit_aux_data_sockaddr *axs = (void *)aux; | |
723 | ||
724 | audit_log_format(ab, "saddr="); | |
725 | audit_log_hex(ab, axs->a, axs->len); | |
726 | break; } | |
1da177e4 LT |
727 | } |
728 | audit_log_end(ab); | |
c0404993 SG |
729 | |
730 | context->aux = aux->next; | |
1da177e4 LT |
731 | kfree(aux); |
732 | } | |
733 | ||
734 | for (i = 0; i < context->name_count; i++) { | |
c0404993 | 735 | ab = audit_log_start(context, AUDIT_PATH); |
1da177e4 LT |
736 | if (!ab) |
737 | continue; /* audit_panic has been called */ | |
738 | audit_log_format(ab, "item=%d", i); | |
83c7d091 DW |
739 | if (context->names[i].name) { |
740 | audit_log_format(ab, " name="); | |
741 | audit_log_untrustedstring(ab, context->names[i].name); | |
742 | } | |
1da177e4 LT |
743 | if (context->names[i].ino != (unsigned long)-1) |
744 | audit_log_format(ab, " inode=%lu dev=%02x:%02x mode=%#o" | |
c0404993 | 745 | " ouid=%d ogid=%d rdev=%02x:%02x", |
1da177e4 LT |
746 | context->names[i].ino, |
747 | MAJOR(context->names[i].dev), | |
748 | MINOR(context->names[i].dev), | |
749 | context->names[i].mode, | |
750 | context->names[i].uid, | |
751 | context->names[i].gid, | |
752 | MAJOR(context->names[i].rdev), | |
753 | MINOR(context->names[i].rdev)); | |
754 | audit_log_end(ab); | |
755 | } | |
756 | } | |
757 | ||
758 | /* Free a per-task audit context. Called from copy_process and | |
759 | * __put_task_struct. */ | |
760 | void audit_free(struct task_struct *tsk) | |
761 | { | |
762 | struct audit_context *context; | |
763 | ||
764 | task_lock(tsk); | |
765 | context = audit_get_context(tsk, 0, 0); | |
766 | task_unlock(tsk); | |
767 | ||
768 | if (likely(!context)) | |
769 | return; | |
770 | ||
771 | /* Check for system calls that do not go through the exit | |
772 | * function (e.g., exit_group), then free context block. */ | |
7ca00264 | 773 | if (context->in_syscall && context->auditable && context->pid != audit_pid) |
1da177e4 LT |
774 | audit_log_exit(context); |
775 | ||
776 | audit_free_context(context); | |
777 | } | |
778 | ||
779 | /* Compute a serial number for the audit record. Audit records are | |
780 | * written to user-space as soon as they are generated, so a complete | |
781 | * audit record may be written in several pieces. The timestamp of the | |
23f32d18 | 782 | * record and this serial number are used by the user-space tools to |
1da177e4 LT |
783 | * determine which pieces belong to the same audit record. The |
784 | * (timestamp,serial) tuple is unique for each syscall and is live from | |
785 | * syscall entry to syscall exit. | |
786 | * | |
787 | * Atomic values are only guaranteed to be 24-bit, so we count down. | |
788 | * | |
789 | * NOTE: Another possibility is to store the formatted records off the | |
790 | * audit context (for those records that have a context), and emit them | |
791 | * all at syscall exit. However, this could delay the reporting of | |
792 | * significant errors until syscall exit (or never, if the system | |
793 | * halts). */ | |
794 | static inline unsigned int audit_serial(void) | |
795 | { | |
796 | static atomic_t serial = ATOMIC_INIT(0xffffff); | |
797 | unsigned int a, b; | |
798 | ||
799 | do { | |
800 | a = atomic_read(&serial); | |
801 | if (atomic_dec_and_test(&serial)) | |
802 | atomic_set(&serial, 0xffffff); | |
803 | b = atomic_read(&serial); | |
804 | } while (b != a - 1); | |
805 | ||
806 | return 0xffffff - b; | |
807 | } | |
808 | ||
809 | /* Fill in audit context at syscall entry. This only happens if the | |
810 | * audit context was created when the task was created and the state or | |
811 | * filters demand the audit context be built. If the state from the | |
812 | * per-task filter or from the per-syscall filter is AUDIT_RECORD_CONTEXT, | |
813 | * then the record will be written at syscall exit time (otherwise, it | |
814 | * will only be written if another part of the kernel requests that it | |
815 | * be written). */ | |
2fd6f58b | 816 | void audit_syscall_entry(struct task_struct *tsk, int arch, int major, |
1da177e4 LT |
817 | unsigned long a1, unsigned long a2, |
818 | unsigned long a3, unsigned long a4) | |
819 | { | |
820 | struct audit_context *context = tsk->audit_context; | |
821 | enum audit_state state; | |
822 | ||
823 | BUG_ON(!context); | |
824 | ||
825 | /* This happens only on certain architectures that make system | |
826 | * calls in kernel_thread via the entry.S interface, instead of | |
827 | * with direct calls. (If you are porting to a new | |
828 | * architecture, hitting this condition can indicate that you | |
829 | * got the _exit/_leave calls backward in entry.S.) | |
830 | * | |
831 | * i386 no | |
832 | * x86_64 no | |
833 | * ppc64 yes (see arch/ppc64/kernel/misc.S) | |
834 | * | |
835 | * This also happens with vm86 emulation in a non-nested manner | |
836 | * (entries without exits), so this case must be caught. | |
837 | */ | |
838 | if (context->in_syscall) { | |
839 | struct audit_context *newctx; | |
840 | ||
841 | #if defined(__NR_vm86) && defined(__NR_vm86old) | |
842 | /* vm86 mode should only be entered once */ | |
843 | if (major == __NR_vm86 || major == __NR_vm86old) | |
844 | return; | |
845 | #endif | |
846 | #if AUDIT_DEBUG | |
847 | printk(KERN_ERR | |
848 | "audit(:%d) pid=%d in syscall=%d;" | |
849 | " entering syscall=%d\n", | |
850 | context->serial, tsk->pid, context->major, major); | |
851 | #endif | |
852 | newctx = audit_alloc_context(context->state); | |
853 | if (newctx) { | |
854 | newctx->previous = context; | |
855 | context = newctx; | |
856 | tsk->audit_context = newctx; | |
857 | } else { | |
858 | /* If we can't alloc a new context, the best we | |
859 | * can do is to leak memory (any pending putname | |
860 | * will be lost). The only other alternative is | |
861 | * to abandon auditing. */ | |
862 | audit_zero_context(context, context->state); | |
863 | } | |
864 | } | |
865 | BUG_ON(context->in_syscall || context->name_count); | |
866 | ||
867 | if (!audit_enabled) | |
868 | return; | |
869 | ||
2fd6f58b | 870 | context->arch = arch; |
1da177e4 LT |
871 | context->major = major; |
872 | context->argv[0] = a1; | |
873 | context->argv[1] = a2; | |
874 | context->argv[2] = a3; | |
875 | context->argv[3] = a4; | |
876 | ||
877 | state = context->state; | |
878 | if (state == AUDIT_SETUP_CONTEXT || state == AUDIT_BUILD_CONTEXT) | |
879 | state = audit_filter_syscall(tsk, context, &audit_entlist); | |
880 | if (likely(state == AUDIT_DISABLED)) | |
881 | return; | |
882 | ||
883 | context->serial = audit_serial(); | |
884 | context->ctime = CURRENT_TIME; | |
885 | context->in_syscall = 1; | |
886 | context->auditable = !!(state == AUDIT_RECORD_CONTEXT); | |
887 | } | |
888 | ||
889 | /* Tear down after system call. If the audit context has been marked as | |
890 | * auditable (either because of the AUDIT_RECORD_CONTEXT state from | |
891 | * filtering, or because some other part of the kernel write an audit | |
892 | * message), then write out the syscall information. In call cases, | |
893 | * free the names stored from getname(). */ | |
2fd6f58b | 894 | void audit_syscall_exit(struct task_struct *tsk, int valid, long return_code) |
1da177e4 LT |
895 | { |
896 | struct audit_context *context; | |
897 | ||
898 | get_task_struct(tsk); | |
899 | task_lock(tsk); | |
2fd6f58b | 900 | context = audit_get_context(tsk, valid, return_code); |
1da177e4 LT |
901 | task_unlock(tsk); |
902 | ||
903 | /* Not having a context here is ok, since the parent may have | |
904 | * called __put_task_struct. */ | |
905 | if (likely(!context)) | |
906 | return; | |
907 | ||
7ca00264 | 908 | if (context->in_syscall && context->auditable && context->pid != audit_pid) |
1da177e4 LT |
909 | audit_log_exit(context); |
910 | ||
911 | context->in_syscall = 0; | |
912 | context->auditable = 0; | |
2fd6f58b | 913 | |
1da177e4 LT |
914 | if (context->previous) { |
915 | struct audit_context *new_context = context->previous; | |
916 | context->previous = NULL; | |
917 | audit_free_context(context); | |
918 | tsk->audit_context = new_context; | |
919 | } else { | |
920 | audit_free_names(context); | |
921 | audit_free_aux(context); | |
922 | audit_zero_context(context, context->state); | |
923 | tsk->audit_context = context; | |
924 | } | |
925 | put_task_struct(tsk); | |
926 | } | |
927 | ||
928 | /* Add a name to the list. Called from fs/namei.c:getname(). */ | |
929 | void audit_getname(const char *name) | |
930 | { | |
931 | struct audit_context *context = current->audit_context; | |
932 | ||
933 | if (!context || IS_ERR(name) || !name) | |
934 | return; | |
935 | ||
936 | if (!context->in_syscall) { | |
937 | #if AUDIT_DEBUG == 2 | |
938 | printk(KERN_ERR "%s:%d(:%d): ignoring getname(%p)\n", | |
939 | __FILE__, __LINE__, context->serial, name); | |
940 | dump_stack(); | |
941 | #endif | |
942 | return; | |
943 | } | |
944 | BUG_ON(context->name_count >= AUDIT_NAMES); | |
945 | context->names[context->name_count].name = name; | |
946 | context->names[context->name_count].ino = (unsigned long)-1; | |
947 | ++context->name_count; | |
948 | } | |
949 | ||
950 | /* Intercept a putname request. Called from | |
951 | * include/linux/fs.h:putname(). If we have stored the name from | |
952 | * getname in the audit context, then we delay the putname until syscall | |
953 | * exit. */ | |
954 | void audit_putname(const char *name) | |
955 | { | |
956 | struct audit_context *context = current->audit_context; | |
957 | ||
958 | BUG_ON(!context); | |
959 | if (!context->in_syscall) { | |
960 | #if AUDIT_DEBUG == 2 | |
961 | printk(KERN_ERR "%s:%d(:%d): __putname(%p)\n", | |
962 | __FILE__, __LINE__, context->serial, name); | |
963 | if (context->name_count) { | |
964 | int i; | |
965 | for (i = 0; i < context->name_count; i++) | |
966 | printk(KERN_ERR "name[%d] = %p = %s\n", i, | |
967 | context->names[i].name, | |
968 | context->names[i].name); | |
969 | } | |
970 | #endif | |
971 | __putname(name); | |
972 | } | |
973 | #if AUDIT_DEBUG | |
974 | else { | |
975 | ++context->put_count; | |
976 | if (context->put_count > context->name_count) { | |
977 | printk(KERN_ERR "%s:%d(:%d): major=%d" | |
978 | " in_syscall=%d putname(%p) name_count=%d" | |
979 | " put_count=%d\n", | |
980 | __FILE__, __LINE__, | |
981 | context->serial, context->major, | |
982 | context->in_syscall, name, context->name_count, | |
983 | context->put_count); | |
984 | dump_stack(); | |
985 | } | |
986 | } | |
987 | #endif | |
988 | } | |
989 | ||
990 | /* Store the inode and device from a lookup. Called from | |
991 | * fs/namei.c:path_lookup(). */ | |
992 | void audit_inode(const char *name, const struct inode *inode) | |
993 | { | |
994 | int idx; | |
995 | struct audit_context *context = current->audit_context; | |
996 | ||
997 | if (!context->in_syscall) | |
998 | return; | |
999 | if (context->name_count | |
1000 | && context->names[context->name_count-1].name | |
1001 | && context->names[context->name_count-1].name == name) | |
1002 | idx = context->name_count - 1; | |
1003 | else if (context->name_count > 1 | |
1004 | && context->names[context->name_count-2].name | |
1005 | && context->names[context->name_count-2].name == name) | |
1006 | idx = context->name_count - 2; | |
1007 | else { | |
1008 | /* FIXME: how much do we care about inodes that have no | |
1009 | * associated name? */ | |
1010 | if (context->name_count >= AUDIT_NAMES - AUDIT_NAMES_RESERVED) | |
1011 | return; | |
1012 | idx = context->name_count++; | |
1013 | context->names[idx].name = NULL; | |
1014 | #if AUDIT_DEBUG | |
1015 | ++context->ino_count; | |
1016 | #endif | |
1017 | } | |
1018 | context->names[idx].ino = inode->i_ino; | |
1019 | context->names[idx].dev = inode->i_sb->s_dev; | |
1020 | context->names[idx].mode = inode->i_mode; | |
1021 | context->names[idx].uid = inode->i_uid; | |
1022 | context->names[idx].gid = inode->i_gid; | |
1023 | context->names[idx].rdev = inode->i_rdev; | |
1024 | } | |
1025 | ||
197c69c6 | 1026 | int audit_get_stamp(struct audit_context *ctx, |
d812ddbb | 1027 | struct timespec *t, unsigned int *serial) |
1da177e4 LT |
1028 | { |
1029 | if (ctx) { | |
1030 | t->tv_sec = ctx->ctime.tv_sec; | |
1031 | t->tv_nsec = ctx->ctime.tv_nsec; | |
1032 | *serial = ctx->serial; | |
1033 | ctx->auditable = 1; | |
197c69c6 | 1034 | return 1; |
1da177e4 | 1035 | } |
197c69c6 | 1036 | return 0; |
1da177e4 LT |
1037 | } |
1038 | ||
456be6cd | 1039 | int audit_set_loginuid(struct task_struct *task, uid_t loginuid) |
1da177e4 | 1040 | { |
456be6cd | 1041 | if (task->audit_context) { |
c0404993 SG |
1042 | struct audit_buffer *ab; |
1043 | ||
1044 | ab = audit_log_start(NULL, AUDIT_LOGIN); | |
1045 | if (ab) { | |
1046 | audit_log_format(ab, "login pid=%d uid=%u " | |
1047 | "old loginuid=%u new loginuid=%u", | |
1048 | task->pid, task->uid, | |
1049 | task->audit_context->loginuid, loginuid); | |
1050 | audit_log_end(ab); | |
1051 | } | |
456be6cd | 1052 | task->audit_context->loginuid = loginuid; |
1da177e4 LT |
1053 | } |
1054 | return 0; | |
1055 | } | |
1056 | ||
1057 | uid_t audit_get_loginuid(struct audit_context *ctx) | |
1058 | { | |
1059 | return ctx ? ctx->loginuid : -1; | |
1060 | } | |
1061 | ||
1062 | int audit_ipc_perms(unsigned long qbytes, uid_t uid, gid_t gid, mode_t mode) | |
1063 | { | |
1064 | struct audit_aux_data_ipcctl *ax; | |
1065 | struct audit_context *context = current->audit_context; | |
1066 | ||
1067 | if (likely(!context)) | |
1068 | return 0; | |
1069 | ||
1070 | ax = kmalloc(sizeof(*ax), GFP_KERNEL); | |
1071 | if (!ax) | |
1072 | return -ENOMEM; | |
1073 | ||
1074 | ax->qbytes = qbytes; | |
1075 | ax->uid = uid; | |
1076 | ax->gid = gid; | |
1077 | ax->mode = mode; | |
1078 | ||
c0404993 | 1079 | ax->d.type = AUDIT_IPC; |
1da177e4 LT |
1080 | ax->d.next = context->aux; |
1081 | context->aux = (void *)ax; | |
1082 | return 0; | |
1083 | } | |
c2f0c7c3 | 1084 | |
3ec3b2fb DW |
1085 | int audit_socketcall(int nargs, unsigned long *args) |
1086 | { | |
1087 | struct audit_aux_data_socketcall *ax; | |
1088 | struct audit_context *context = current->audit_context; | |
1089 | ||
1090 | if (likely(!context)) | |
1091 | return 0; | |
1092 | ||
1093 | ax = kmalloc(sizeof(*ax) + nargs * sizeof(unsigned long), GFP_KERNEL); | |
1094 | if (!ax) | |
1095 | return -ENOMEM; | |
1096 | ||
1097 | ax->nargs = nargs; | |
1098 | memcpy(ax->args, args, nargs * sizeof(unsigned long)); | |
1099 | ||
1100 | ax->d.type = AUDIT_SOCKETCALL; | |
1101 | ax->d.next = context->aux; | |
1102 | context->aux = (void *)ax; | |
1103 | return 0; | |
1104 | } | |
1105 | ||
1106 | int audit_sockaddr(int len, void *a) | |
1107 | { | |
1108 | struct audit_aux_data_sockaddr *ax; | |
1109 | struct audit_context *context = current->audit_context; | |
1110 | ||
1111 | if (likely(!context)) | |
1112 | return 0; | |
1113 | ||
1114 | ax = kmalloc(sizeof(*ax) + len, GFP_KERNEL); | |
1115 | if (!ax) | |
1116 | return -ENOMEM; | |
1117 | ||
1118 | ax->len = len; | |
1119 | memcpy(ax->a, a, len); | |
1120 | ||
1121 | ax->d.type = AUDIT_SOCKADDR; | |
1122 | ax->d.next = context->aux; | |
1123 | context->aux = (void *)ax; | |
1124 | return 0; | |
1125 | } | |
1126 | ||
c2f0c7c3 SG |
1127 | void audit_signal_info(int sig, struct task_struct *t) |
1128 | { | |
1129 | extern pid_t audit_sig_pid; | |
1130 | extern uid_t audit_sig_uid; | |
c2f0c7c3 SG |
1131 | |
1132 | if (unlikely(audit_pid && t->pid == audit_pid)) { | |
1133 | if (sig == SIGTERM || sig == SIGHUP) { | |
1134 | struct audit_context *ctx = current->audit_context; | |
1135 | audit_sig_pid = current->pid; | |
1136 | if (ctx) | |
1137 | audit_sig_uid = ctx->loginuid; | |
1138 | else | |
1139 | audit_sig_uid = current->uid; | |
1140 | } | |
1141 | } | |
1142 | } | |
1143 |