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