1 /* audit.c -- Auditing support 2 * Gateway between the kernel (e.g., selinux) and the user-space audit daemon. 3 * System-call specific features have moved to auditsc.c 4 * 5 * Copyright 2003-2007 Red Hat Inc., Durham, North Carolina. 6 * All Rights Reserved. 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License as published by 10 * the Free Software Foundation; either version 2 of the License, or 11 * (at your option) any later version. 12 * 13 * This program is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 * GNU General Public License for more details. 17 * 18 * You should have received a copy of the GNU General Public License 19 * along with this program; if not, write to the Free Software 20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 21 * 22 * Written by Rickard E. (Rik) Faith <faith@redhat.com> 23 * 24 * Goals: 1) Integrate fully with Security Modules. 25 * 2) Minimal run-time overhead: 26 * a) Minimal when syscall auditing is disabled (audit_enable=0). 27 * b) Small when syscall auditing is enabled and no audit record 28 * is generated (defer as much work as possible to record 29 * generation time): 30 * i) context is allocated, 31 * ii) names from getname are stored without a copy, and 32 * iii) inode information stored from path_lookup. 33 * 3) Ability to disable syscall auditing at boot time (audit=0). 34 * 4) Usable by other parts of the kernel (if audit_log* is called, 35 * then a syscall record will be generated automatically for the 36 * current syscall). 37 * 5) Netlink interface to user-space. 38 * 6) Support low-overhead kernel-based filtering to minimize the 39 * information that must be passed to user-space. 40 * 41 * Example user-space utilities: http://people.redhat.com/sgrubb/audit/ 42 */ 43 44 #include <linux/init.h> 45 #include <asm/types.h> 46 #include <asm/atomic.h> 47 #include <linux/mm.h> 48 #include <linux/module.h> 49 #include <linux/err.h> 50 #include <linux/kthread.h> 51 52 #include <linux/audit.h> 53 54 #include <net/sock.h> 55 #include <net/netlink.h> 56 #include <linux/skbuff.h> 57 #include <linux/netlink.h> 58 #include <linux/inotify.h> 59 #include <linux/freezer.h> 60 #include <linux/tty.h> 61 62 #include "audit.h" 63 64 /* No auditing will take place until audit_initialized != 0. 65 * (Initialization happens after skb_init is called.) */ 66 static int audit_initialized; 67 68 #define AUDIT_OFF 0 69 #define AUDIT_ON 1 70 #define AUDIT_LOCKED 2 71 int audit_enabled; 72 int audit_ever_enabled; 73 74 /* Default state when kernel boots without any parameters. */ 75 static int audit_default; 76 77 /* If auditing cannot proceed, audit_failure selects what happens. */ 78 static int audit_failure = AUDIT_FAIL_PRINTK; 79 80 /* 81 * If audit records are to be written to the netlink socket, audit_pid 82 * contains the pid of the auditd process and audit_nlk_pid contains 83 * the pid to use to send netlink messages to that process. 84 */ 85 int audit_pid; 86 static int audit_nlk_pid; 87 88 /* If audit_rate_limit is non-zero, limit the rate of sending audit records 89 * to that number per second. This prevents DoS attacks, but results in 90 * audit records being dropped. */ 91 static int audit_rate_limit; 92 93 /* Number of outstanding audit_buffers allowed. */ 94 static int audit_backlog_limit = 64; 95 static int audit_backlog_wait_time = 60 * HZ; 96 static int audit_backlog_wait_overflow = 0; 97 98 /* The identity of the user shutting down the audit system. */ 99 uid_t audit_sig_uid = -1; 100 pid_t audit_sig_pid = -1; 101 u32 audit_sig_sid = 0; 102 103 /* Records can be lost in several ways: 104 0) [suppressed in audit_alloc] 105 1) out of memory in audit_log_start [kmalloc of struct audit_buffer] 106 2) out of memory in audit_log_move [alloc_skb] 107 3) suppressed due to audit_rate_limit 108 4) suppressed due to audit_backlog_limit 109 */ 110 static atomic_t audit_lost = ATOMIC_INIT(0); 111 112 /* The netlink socket. */ 113 static struct sock *audit_sock; 114 115 /* Inotify handle. */ 116 struct inotify_handle *audit_ih; 117 118 /* Hash for inode-based rules */ 119 struct list_head audit_inode_hash[AUDIT_INODE_BUCKETS]; 120 121 /* The audit_freelist is a list of pre-allocated audit buffers (if more 122 * than AUDIT_MAXFREE are in use, the audit buffer is freed instead of 123 * being placed on the freelist). */ 124 static DEFINE_SPINLOCK(audit_freelist_lock); 125 static int audit_freelist_count; 126 static LIST_HEAD(audit_freelist); 127 128 static struct sk_buff_head audit_skb_queue; 129 static struct task_struct *kauditd_task; 130 static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait); 131 static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait); 132 133 /* Serialize requests from userspace. */ 134 static DEFINE_MUTEX(audit_cmd_mutex); 135 136 /* AUDIT_BUFSIZ is the size of the temporary buffer used for formatting 137 * audit records. Since printk uses a 1024 byte buffer, this buffer 138 * should be at least that large. */ 139 #define AUDIT_BUFSIZ 1024 140 141 /* AUDIT_MAXFREE is the number of empty audit_buffers we keep on the 142 * audit_freelist. Doing so eliminates many kmalloc/kfree calls. */ 143 #define AUDIT_MAXFREE (2*NR_CPUS) 144 145 /* The audit_buffer is used when formatting an audit record. The caller 146 * locks briefly to get the record off the freelist or to allocate the 147 * buffer, and locks briefly to send the buffer to the netlink layer or 148 * to place it on a transmit queue. Multiple audit_buffers can be in 149 * use simultaneously. */ 150 struct audit_buffer { 151 struct list_head list; 152 struct sk_buff *skb; /* formatted skb ready to send */ 153 struct audit_context *ctx; /* NULL or associated context */ 154 gfp_t gfp_mask; 155 }; 156 157 static void audit_set_pid(struct audit_buffer *ab, pid_t pid) 158 { 159 if (ab) { 160 struct nlmsghdr *nlh = nlmsg_hdr(ab->skb); 161 nlh->nlmsg_pid = pid; 162 } 163 } 164 165 void audit_panic(const char *message) 166 { 167 switch (audit_failure) 168 { 169 case AUDIT_FAIL_SILENT: 170 break; 171 case AUDIT_FAIL_PRINTK: 172 if (printk_ratelimit()) 173 printk(KERN_ERR "audit: %s\n", message); 174 break; 175 case AUDIT_FAIL_PANIC: 176 /* test audit_pid since printk is always losey, why bother? */ 177 if (audit_pid) 178 panic("audit: %s\n", message); 179 break; 180 } 181 } 182 183 static inline int audit_rate_check(void) 184 { 185 static unsigned long last_check = 0; 186 static int messages = 0; 187 static DEFINE_SPINLOCK(lock); 188 unsigned long flags; 189 unsigned long now; 190 unsigned long elapsed; 191 int retval = 0; 192 193 if (!audit_rate_limit) return 1; 194 195 spin_lock_irqsave(&lock, flags); 196 if (++messages < audit_rate_limit) { 197 retval = 1; 198 } else { 199 now = jiffies; 200 elapsed = now - last_check; 201 if (elapsed > HZ) { 202 last_check = now; 203 messages = 0; 204 retval = 1; 205 } 206 } 207 spin_unlock_irqrestore(&lock, flags); 208 209 return retval; 210 } 211 212 /** 213 * audit_log_lost - conditionally log lost audit message event 214 * @message: the message stating reason for lost audit message 215 * 216 * Emit at least 1 message per second, even if audit_rate_check is 217 * throttling. 218 * Always increment the lost messages counter. 219 */ 220 void audit_log_lost(const char *message) 221 { 222 static unsigned long last_msg = 0; 223 static DEFINE_SPINLOCK(lock); 224 unsigned long flags; 225 unsigned long now; 226 int print; 227 228 atomic_inc(&audit_lost); 229 230 print = (audit_failure == AUDIT_FAIL_PANIC || !audit_rate_limit); 231 232 if (!print) { 233 spin_lock_irqsave(&lock, flags); 234 now = jiffies; 235 if (now - last_msg > HZ) { 236 print = 1; 237 last_msg = now; 238 } 239 spin_unlock_irqrestore(&lock, flags); 240 } 241 242 if (print) { 243 if (printk_ratelimit()) 244 printk(KERN_WARNING 245 "audit: audit_lost=%d audit_rate_limit=%d " 246 "audit_backlog_limit=%d\n", 247 atomic_read(&audit_lost), 248 audit_rate_limit, 249 audit_backlog_limit); 250 audit_panic(message); 251 } 252 } 253 254 static int audit_log_config_change(char *function_name, int new, int old, 255 uid_t loginuid, u32 sid, int allow_changes) 256 { 257 struct audit_buffer *ab; 258 int rc = 0; 259 260 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE); 261 audit_log_format(ab, "%s=%d old=%d by auid=%u", function_name, new, 262 old, loginuid); 263 if (sid) { 264 char *ctx = NULL; 265 u32 len; 266 267 rc = security_secid_to_secctx(sid, &ctx, &len); 268 if (rc) { 269 audit_log_format(ab, " sid=%u", sid); 270 allow_changes = 0; /* Something weird, deny request */ 271 } else { 272 audit_log_format(ab, " subj=%s", ctx); 273 security_release_secctx(ctx, len); 274 } 275 } 276 audit_log_format(ab, " res=%d", allow_changes); 277 audit_log_end(ab); 278 return rc; 279 } 280 281 static int audit_do_config_change(char *function_name, int *to_change, 282 int new, uid_t loginuid, u32 sid) 283 { 284 int allow_changes, rc = 0, old = *to_change; 285 286 /* check if we are locked */ 287 if (audit_enabled == AUDIT_LOCKED) 288 allow_changes = 0; 289 else 290 allow_changes = 1; 291 292 if (audit_enabled != AUDIT_OFF) { 293 rc = audit_log_config_change(function_name, new, old, 294 loginuid, sid, allow_changes); 295 if (rc) 296 allow_changes = 0; 297 } 298 299 /* If we are allowed, make the change */ 300 if (allow_changes == 1) 301 *to_change = new; 302 /* Not allowed, update reason */ 303 else if (rc == 0) 304 rc = -EPERM; 305 return rc; 306 } 307 308 static int audit_set_rate_limit(int limit, uid_t loginuid, u32 sid) 309 { 310 return audit_do_config_change("audit_rate_limit", &audit_rate_limit, 311 limit, loginuid, sid); 312 } 313 314 static int audit_set_backlog_limit(int limit, uid_t loginuid, u32 sid) 315 { 316 return audit_do_config_change("audit_backlog_limit", &audit_backlog_limit, 317 limit, loginuid, sid); 318 } 319 320 static int audit_set_enabled(int state, uid_t loginuid, u32 sid) 321 { 322 int rc; 323 if (state < AUDIT_OFF || state > AUDIT_LOCKED) 324 return -EINVAL; 325 326 rc = audit_do_config_change("audit_enabled", &audit_enabled, state, 327 loginuid, sid); 328 329 if (!rc) 330 audit_ever_enabled |= !!state; 331 332 return rc; 333 } 334 335 static int audit_set_failure(int state, uid_t loginuid, u32 sid) 336 { 337 if (state != AUDIT_FAIL_SILENT 338 && state != AUDIT_FAIL_PRINTK 339 && state != AUDIT_FAIL_PANIC) 340 return -EINVAL; 341 342 return audit_do_config_change("audit_failure", &audit_failure, state, 343 loginuid, sid); 344 } 345 346 static int kauditd_thread(void *dummy) 347 { 348 struct sk_buff *skb; 349 350 set_freezable(); 351 while (!kthread_should_stop()) { 352 skb = skb_dequeue(&audit_skb_queue); 353 wake_up(&audit_backlog_wait); 354 if (skb) { 355 if (audit_pid) { 356 int err = netlink_unicast(audit_sock, skb, audit_nlk_pid, 0); 357 if (err < 0) { 358 BUG_ON(err != -ECONNREFUSED); /* Shoudn't happen */ 359 printk(KERN_ERR "audit: *NO* daemon at audit_pid=%d\n", audit_pid); 360 audit_log_lost("auditd dissapeared\n"); 361 audit_pid = 0; 362 } 363 } else { 364 if (printk_ratelimit()) 365 printk(KERN_NOTICE "%s\n", skb->data + 366 NLMSG_SPACE(0)); 367 else 368 audit_log_lost("printk limit exceeded\n"); 369 kfree_skb(skb); 370 } 371 } else { 372 DECLARE_WAITQUEUE(wait, current); 373 set_current_state(TASK_INTERRUPTIBLE); 374 add_wait_queue(&kauditd_wait, &wait); 375 376 if (!skb_queue_len(&audit_skb_queue)) { 377 try_to_freeze(); 378 schedule(); 379 } 380 381 __set_current_state(TASK_RUNNING); 382 remove_wait_queue(&kauditd_wait, &wait); 383 } 384 } 385 return 0; 386 } 387 388 static int audit_prepare_user_tty(pid_t pid, uid_t loginuid) 389 { 390 struct task_struct *tsk; 391 int err; 392 393 read_lock(&tasklist_lock); 394 tsk = find_task_by_pid(pid); 395 err = -ESRCH; 396 if (!tsk) 397 goto out; 398 err = 0; 399 400 spin_lock_irq(&tsk->sighand->siglock); 401 if (!tsk->signal->audit_tty) 402 err = -EPERM; 403 spin_unlock_irq(&tsk->sighand->siglock); 404 if (err) 405 goto out; 406 407 tty_audit_push_task(tsk, loginuid); 408 out: 409 read_unlock(&tasklist_lock); 410 return err; 411 } 412 413 int audit_send_list(void *_dest) 414 { 415 struct audit_netlink_list *dest = _dest; 416 int pid = dest->pid; 417 struct sk_buff *skb; 418 419 /* wait for parent to finish and send an ACK */ 420 mutex_lock(&audit_cmd_mutex); 421 mutex_unlock(&audit_cmd_mutex); 422 423 while ((skb = __skb_dequeue(&dest->q)) != NULL) 424 netlink_unicast(audit_sock, skb, pid, 0); 425 426 kfree(dest); 427 428 return 0; 429 } 430 431 #ifdef CONFIG_AUDIT_TREE 432 static int prune_tree_thread(void *unused) 433 { 434 mutex_lock(&audit_cmd_mutex); 435 audit_prune_trees(); 436 mutex_unlock(&audit_cmd_mutex); 437 return 0; 438 } 439 440 void audit_schedule_prune(void) 441 { 442 kthread_run(prune_tree_thread, NULL, "audit_prune_tree"); 443 } 444 #endif 445 446 struct sk_buff *audit_make_reply(int pid, int seq, int type, int done, 447 int multi, void *payload, int size) 448 { 449 struct sk_buff *skb; 450 struct nlmsghdr *nlh; 451 int len = NLMSG_SPACE(size); 452 void *data; 453 int flags = multi ? NLM_F_MULTI : 0; 454 int t = done ? NLMSG_DONE : type; 455 456 skb = alloc_skb(len, GFP_KERNEL); 457 if (!skb) 458 return NULL; 459 460 nlh = NLMSG_PUT(skb, pid, seq, t, size); 461 nlh->nlmsg_flags = flags; 462 data = NLMSG_DATA(nlh); 463 memcpy(data, payload, size); 464 return skb; 465 466 nlmsg_failure: /* Used by NLMSG_PUT */ 467 if (skb) 468 kfree_skb(skb); 469 return NULL; 470 } 471 472 /** 473 * audit_send_reply - send an audit reply message via netlink 474 * @pid: process id to send reply to 475 * @seq: sequence number 476 * @type: audit message type 477 * @done: done (last) flag 478 * @multi: multi-part message flag 479 * @payload: payload data 480 * @size: payload size 481 * 482 * Allocates an skb, builds the netlink message, and sends it to the pid. 483 * No failure notifications. 484 */ 485 void audit_send_reply(int pid, int seq, int type, int done, int multi, 486 void *payload, int size) 487 { 488 struct sk_buff *skb; 489 skb = audit_make_reply(pid, seq, type, done, multi, payload, size); 490 if (!skb) 491 return; 492 /* Ignore failure. It'll only happen if the sender goes away, 493 because our timeout is set to infinite. */ 494 netlink_unicast(audit_sock, skb, pid, 0); 495 return; 496 } 497 498 /* 499 * Check for appropriate CAP_AUDIT_ capabilities on incoming audit 500 * control messages. 501 */ 502 static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type) 503 { 504 int err = 0; 505 506 switch (msg_type) { 507 case AUDIT_GET: 508 case AUDIT_LIST: 509 case AUDIT_LIST_RULES: 510 case AUDIT_SET: 511 case AUDIT_ADD: 512 case AUDIT_ADD_RULE: 513 case AUDIT_DEL: 514 case AUDIT_DEL_RULE: 515 case AUDIT_SIGNAL_INFO: 516 case AUDIT_TTY_GET: 517 case AUDIT_TTY_SET: 518 case AUDIT_TRIM: 519 case AUDIT_MAKE_EQUIV: 520 if (security_netlink_recv(skb, CAP_AUDIT_CONTROL)) 521 err = -EPERM; 522 break; 523 case AUDIT_USER: 524 case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG: 525 case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2: 526 if (security_netlink_recv(skb, CAP_AUDIT_WRITE)) 527 err = -EPERM; 528 break; 529 default: /* bad msg */ 530 err = -EINVAL; 531 } 532 533 return err; 534 } 535 536 static int audit_log_common_recv_msg(struct audit_buffer **ab, u16 msg_type, 537 u32 pid, u32 uid, uid_t auid, u32 sid) 538 { 539 int rc = 0; 540 char *ctx = NULL; 541 u32 len; 542 543 if (!audit_enabled) { 544 *ab = NULL; 545 return rc; 546 } 547 548 *ab = audit_log_start(NULL, GFP_KERNEL, msg_type); 549 audit_log_format(*ab, "user pid=%d uid=%u auid=%u", 550 pid, uid, auid); 551 if (sid) { 552 rc = security_secid_to_secctx(sid, &ctx, &len); 553 if (rc) 554 audit_log_format(*ab, " ssid=%u", sid); 555 else { 556 audit_log_format(*ab, " subj=%s", ctx); 557 security_release_secctx(ctx, len); 558 } 559 } 560 561 return rc; 562 } 563 564 static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) 565 { 566 u32 uid, pid, seq, sid; 567 void *data; 568 struct audit_status *status_get, status_set; 569 int err; 570 struct audit_buffer *ab; 571 u16 msg_type = nlh->nlmsg_type; 572 uid_t loginuid; /* loginuid of sender */ 573 struct audit_sig_info *sig_data; 574 char *ctx = NULL; 575 u32 len; 576 577 err = audit_netlink_ok(skb, msg_type); 578 if (err) 579 return err; 580 581 /* As soon as there's any sign of userspace auditd, 582 * start kauditd to talk to it */ 583 if (!kauditd_task) 584 kauditd_task = kthread_run(kauditd_thread, NULL, "kauditd"); 585 if (IS_ERR(kauditd_task)) { 586 err = PTR_ERR(kauditd_task); 587 kauditd_task = NULL; 588 return err; 589 } 590 591 pid = NETLINK_CREDS(skb)->pid; 592 uid = NETLINK_CREDS(skb)->uid; 593 loginuid = NETLINK_CB(skb).loginuid; 594 sid = NETLINK_CB(skb).sid; 595 seq = nlh->nlmsg_seq; 596 data = NLMSG_DATA(nlh); 597 598 switch (msg_type) { 599 case AUDIT_GET: 600 status_set.enabled = audit_enabled; 601 status_set.failure = audit_failure; 602 status_set.pid = audit_pid; 603 status_set.rate_limit = audit_rate_limit; 604 status_set.backlog_limit = audit_backlog_limit; 605 status_set.lost = atomic_read(&audit_lost); 606 status_set.backlog = skb_queue_len(&audit_skb_queue); 607 audit_send_reply(NETLINK_CB(skb).pid, seq, AUDIT_GET, 0, 0, 608 &status_set, sizeof(status_set)); 609 break; 610 case AUDIT_SET: 611 if (nlh->nlmsg_len < sizeof(struct audit_status)) 612 return -EINVAL; 613 status_get = (struct audit_status *)data; 614 if (status_get->mask & AUDIT_STATUS_ENABLED) { 615 err = audit_set_enabled(status_get->enabled, 616 loginuid, sid); 617 if (err < 0) return err; 618 } 619 if (status_get->mask & AUDIT_STATUS_FAILURE) { 620 err = audit_set_failure(status_get->failure, 621 loginuid, sid); 622 if (err < 0) return err; 623 } 624 if (status_get->mask & AUDIT_STATUS_PID) { 625 int new_pid = status_get->pid; 626 627 if (audit_enabled != AUDIT_OFF) 628 audit_log_config_change("audit_pid", new_pid, 629 audit_pid, loginuid, 630 sid, 1); 631 632 audit_pid = new_pid; 633 audit_nlk_pid = NETLINK_CB(skb).pid; 634 } 635 if (status_get->mask & AUDIT_STATUS_RATE_LIMIT) 636 err = audit_set_rate_limit(status_get->rate_limit, 637 loginuid, sid); 638 if (status_get->mask & AUDIT_STATUS_BACKLOG_LIMIT) 639 err = audit_set_backlog_limit(status_get->backlog_limit, 640 loginuid, sid); 641 break; 642 case AUDIT_USER: 643 case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG: 644 case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2: 645 if (!audit_enabled && msg_type != AUDIT_USER_AVC) 646 return 0; 647 648 err = audit_filter_user(&NETLINK_CB(skb), msg_type); 649 if (err == 1) { 650 err = 0; 651 if (msg_type == AUDIT_USER_TTY) { 652 err = audit_prepare_user_tty(pid, loginuid); 653 if (err) 654 break; 655 } 656 audit_log_common_recv_msg(&ab, msg_type, pid, uid, 657 loginuid, sid); 658 659 if (msg_type != AUDIT_USER_TTY) 660 audit_log_format(ab, " msg='%.1024s'", 661 (char *)data); 662 else { 663 int size; 664 665 audit_log_format(ab, " msg="); 666 size = nlmsg_len(nlh); 667 audit_log_n_untrustedstring(ab, size, 668 data); 669 } 670 audit_set_pid(ab, pid); 671 audit_log_end(ab); 672 } 673 break; 674 case AUDIT_ADD: 675 case AUDIT_DEL: 676 if (nlmsg_len(nlh) < sizeof(struct audit_rule)) 677 return -EINVAL; 678 if (audit_enabled == AUDIT_LOCKED) { 679 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE, pid, 680 uid, loginuid, sid); 681 682 audit_log_format(ab, " audit_enabled=%d res=0", 683 audit_enabled); 684 audit_log_end(ab); 685 return -EPERM; 686 } 687 /* fallthrough */ 688 case AUDIT_LIST: 689 err = audit_receive_filter(nlh->nlmsg_type, NETLINK_CB(skb).pid, 690 uid, seq, data, nlmsg_len(nlh), 691 loginuid, sid); 692 break; 693 case AUDIT_ADD_RULE: 694 case AUDIT_DEL_RULE: 695 if (nlmsg_len(nlh) < sizeof(struct audit_rule_data)) 696 return -EINVAL; 697 if (audit_enabled == AUDIT_LOCKED) { 698 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE, pid, 699 uid, loginuid, sid); 700 701 audit_log_format(ab, " audit_enabled=%d res=0", 702 audit_enabled); 703 audit_log_end(ab); 704 return -EPERM; 705 } 706 /* fallthrough */ 707 case AUDIT_LIST_RULES: 708 err = audit_receive_filter(nlh->nlmsg_type, NETLINK_CB(skb).pid, 709 uid, seq, data, nlmsg_len(nlh), 710 loginuid, sid); 711 break; 712 case AUDIT_TRIM: 713 audit_trim_trees(); 714 715 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE, pid, 716 uid, loginuid, sid); 717 718 audit_log_format(ab, " op=trim res=1"); 719 audit_log_end(ab); 720 break; 721 case AUDIT_MAKE_EQUIV: { 722 void *bufp = data; 723 u32 sizes[2]; 724 size_t len = nlmsg_len(nlh); 725 char *old, *new; 726 727 err = -EINVAL; 728 if (len < 2 * sizeof(u32)) 729 break; 730 memcpy(sizes, bufp, 2 * sizeof(u32)); 731 bufp += 2 * sizeof(u32); 732 len -= 2 * sizeof(u32); 733 old = audit_unpack_string(&bufp, &len, sizes[0]); 734 if (IS_ERR(old)) { 735 err = PTR_ERR(old); 736 break; 737 } 738 new = audit_unpack_string(&bufp, &len, sizes[1]); 739 if (IS_ERR(new)) { 740 err = PTR_ERR(new); 741 kfree(old); 742 break; 743 } 744 /* OK, here comes... */ 745 err = audit_tag_tree(old, new); 746 747 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE, pid, 748 uid, loginuid, sid); 749 750 audit_log_format(ab, " op=make_equiv old="); 751 audit_log_untrustedstring(ab, old); 752 audit_log_format(ab, " new="); 753 audit_log_untrustedstring(ab, new); 754 audit_log_format(ab, " res=%d", !err); 755 audit_log_end(ab); 756 kfree(old); 757 kfree(new); 758 break; 759 } 760 case AUDIT_SIGNAL_INFO: 761 err = security_secid_to_secctx(audit_sig_sid, &ctx, &len); 762 if (err) 763 return err; 764 sig_data = kmalloc(sizeof(*sig_data) + len, GFP_KERNEL); 765 if (!sig_data) { 766 security_release_secctx(ctx, len); 767 return -ENOMEM; 768 } 769 sig_data->uid = audit_sig_uid; 770 sig_data->pid = audit_sig_pid; 771 memcpy(sig_data->ctx, ctx, len); 772 security_release_secctx(ctx, len); 773 audit_send_reply(NETLINK_CB(skb).pid, seq, AUDIT_SIGNAL_INFO, 774 0, 0, sig_data, sizeof(*sig_data) + len); 775 kfree(sig_data); 776 break; 777 case AUDIT_TTY_GET: { 778 struct audit_tty_status s; 779 struct task_struct *tsk; 780 781 read_lock(&tasklist_lock); 782 tsk = find_task_by_pid(pid); 783 if (!tsk) 784 err = -ESRCH; 785 else { 786 spin_lock_irq(&tsk->sighand->siglock); 787 s.enabled = tsk->signal->audit_tty != 0; 788 spin_unlock_irq(&tsk->sighand->siglock); 789 } 790 read_unlock(&tasklist_lock); 791 audit_send_reply(NETLINK_CB(skb).pid, seq, AUDIT_TTY_GET, 0, 0, 792 &s, sizeof(s)); 793 break; 794 } 795 case AUDIT_TTY_SET: { 796 struct audit_tty_status *s; 797 struct task_struct *tsk; 798 799 if (nlh->nlmsg_len < sizeof(struct audit_tty_status)) 800 return -EINVAL; 801 s = data; 802 if (s->enabled != 0 && s->enabled != 1) 803 return -EINVAL; 804 read_lock(&tasklist_lock); 805 tsk = find_task_by_pid(pid); 806 if (!tsk) 807 err = -ESRCH; 808 else { 809 spin_lock_irq(&tsk->sighand->siglock); 810 tsk->signal->audit_tty = s->enabled != 0; 811 spin_unlock_irq(&tsk->sighand->siglock); 812 } 813 read_unlock(&tasklist_lock); 814 break; 815 } 816 default: 817 err = -EINVAL; 818 break; 819 } 820 821 return err < 0 ? err : 0; 822 } 823 824 /* 825 * Get message from skb (based on rtnetlink_rcv_skb). Each message is 826 * processed by audit_receive_msg. Malformed skbs with wrong length are 827 * discarded silently. 828 */ 829 static void audit_receive_skb(struct sk_buff *skb) 830 { 831 int err; 832 struct nlmsghdr *nlh; 833 u32 rlen; 834 835 while (skb->len >= NLMSG_SPACE(0)) { 836 nlh = nlmsg_hdr(skb); 837 if (nlh->nlmsg_len < sizeof(*nlh) || skb->len < nlh->nlmsg_len) 838 return; 839 rlen = NLMSG_ALIGN(nlh->nlmsg_len); 840 if (rlen > skb->len) 841 rlen = skb->len; 842 if ((err = audit_receive_msg(skb, nlh))) { 843 netlink_ack(skb, nlh, err); 844 } else if (nlh->nlmsg_flags & NLM_F_ACK) 845 netlink_ack(skb, nlh, 0); 846 skb_pull(skb, rlen); 847 } 848 } 849 850 /* Receive messages from netlink socket. */ 851 static void audit_receive(struct sk_buff *skb) 852 { 853 mutex_lock(&audit_cmd_mutex); 854 audit_receive_skb(skb); 855 mutex_unlock(&audit_cmd_mutex); 856 } 857 858 #ifdef CONFIG_AUDITSYSCALL 859 static const struct inotify_operations audit_inotify_ops = { 860 .handle_event = audit_handle_ievent, 861 .destroy_watch = audit_free_parent, 862 }; 863 #endif 864 865 /* Initialize audit support at boot time. */ 866 static int __init audit_init(void) 867 { 868 int i; 869 870 printk(KERN_INFO "audit: initializing netlink socket (%s)\n", 871 audit_default ? "enabled" : "disabled"); 872 audit_sock = netlink_kernel_create(&init_net, NETLINK_AUDIT, 0, 873 audit_receive, NULL, THIS_MODULE); 874 if (!audit_sock) 875 audit_panic("cannot initialize netlink socket"); 876 else 877 audit_sock->sk_sndtimeo = MAX_SCHEDULE_TIMEOUT; 878 879 skb_queue_head_init(&audit_skb_queue); 880 audit_initialized = 1; 881 audit_enabled = audit_default; 882 audit_ever_enabled |= !!audit_default; 883 884 audit_log(NULL, GFP_KERNEL, AUDIT_KERNEL, "initialized"); 885 886 #ifdef CONFIG_AUDITSYSCALL 887 audit_ih = inotify_init(&audit_inotify_ops); 888 if (IS_ERR(audit_ih)) 889 audit_panic("cannot initialize inotify handle"); 890 #endif 891 892 for (i = 0; i < AUDIT_INODE_BUCKETS; i++) 893 INIT_LIST_HEAD(&audit_inode_hash[i]); 894 895 return 0; 896 } 897 __initcall(audit_init); 898 899 /* Process kernel command-line parameter at boot time. audit=0 or audit=1. */ 900 static int __init audit_enable(char *str) 901 { 902 audit_default = !!simple_strtol(str, NULL, 0); 903 printk(KERN_INFO "audit: %s%s\n", 904 audit_default ? "enabled" : "disabled", 905 audit_initialized ? "" : " (after initialization)"); 906 if (audit_initialized) { 907 audit_enabled = audit_default; 908 audit_ever_enabled |= !!audit_default; 909 } 910 return 1; 911 } 912 913 __setup("audit=", audit_enable); 914 915 static void audit_buffer_free(struct audit_buffer *ab) 916 { 917 unsigned long flags; 918 919 if (!ab) 920 return; 921 922 if (ab->skb) 923 kfree_skb(ab->skb); 924 925 spin_lock_irqsave(&audit_freelist_lock, flags); 926 if (audit_freelist_count > AUDIT_MAXFREE) 927 kfree(ab); 928 else { 929 audit_freelist_count++; 930 list_add(&ab->list, &audit_freelist); 931 } 932 spin_unlock_irqrestore(&audit_freelist_lock, flags); 933 } 934 935 static struct audit_buffer * audit_buffer_alloc(struct audit_context *ctx, 936 gfp_t gfp_mask, int type) 937 { 938 unsigned long flags; 939 struct audit_buffer *ab = NULL; 940 struct nlmsghdr *nlh; 941 942 spin_lock_irqsave(&audit_freelist_lock, flags); 943 if (!list_empty(&audit_freelist)) { 944 ab = list_entry(audit_freelist.next, 945 struct audit_buffer, list); 946 list_del(&ab->list); 947 --audit_freelist_count; 948 } 949 spin_unlock_irqrestore(&audit_freelist_lock, flags); 950 951 if (!ab) { 952 ab = kmalloc(sizeof(*ab), gfp_mask); 953 if (!ab) 954 goto err; 955 } 956 957 ab->skb = alloc_skb(AUDIT_BUFSIZ, gfp_mask); 958 if (!ab->skb) 959 goto err; 960 961 ab->ctx = ctx; 962 ab->gfp_mask = gfp_mask; 963 nlh = (struct nlmsghdr *)skb_put(ab->skb, NLMSG_SPACE(0)); 964 nlh->nlmsg_type = type; 965 nlh->nlmsg_flags = 0; 966 nlh->nlmsg_pid = 0; 967 nlh->nlmsg_seq = 0; 968 return ab; 969 err: 970 audit_buffer_free(ab); 971 return NULL; 972 } 973 974 /** 975 * audit_serial - compute a serial number for the audit record 976 * 977 * Compute a serial number for the audit record. Audit records are 978 * written to user-space as soon as they are generated, so a complete 979 * audit record may be written in several pieces. The timestamp of the 980 * record and this serial number are used by the user-space tools to 981 * determine which pieces belong to the same audit record. The 982 * (timestamp,serial) tuple is unique for each syscall and is live from 983 * syscall entry to syscall exit. 984 * 985 * NOTE: Another possibility is to store the formatted records off the 986 * audit context (for those records that have a context), and emit them 987 * all at syscall exit. However, this could delay the reporting of 988 * significant errors until syscall exit (or never, if the system 989 * halts). 990 */ 991 unsigned int audit_serial(void) 992 { 993 static DEFINE_SPINLOCK(serial_lock); 994 static unsigned int serial = 0; 995 996 unsigned long flags; 997 unsigned int ret; 998 999 spin_lock_irqsave(&serial_lock, flags); 1000 do { 1001 ret = ++serial; 1002 } while (unlikely(!ret)); 1003 spin_unlock_irqrestore(&serial_lock, flags); 1004 1005 return ret; 1006 } 1007 1008 static inline void audit_get_stamp(struct audit_context *ctx, 1009 struct timespec *t, unsigned int *serial) 1010 { 1011 if (ctx) 1012 auditsc_get_stamp(ctx, t, serial); 1013 else { 1014 *t = CURRENT_TIME; 1015 *serial = audit_serial(); 1016 } 1017 } 1018 1019 /* Obtain an audit buffer. This routine does locking to obtain the 1020 * audit buffer, but then no locking is required for calls to 1021 * audit_log_*format. If the tsk is a task that is currently in a 1022 * syscall, then the syscall is marked as auditable and an audit record 1023 * will be written at syscall exit. If there is no associated task, tsk 1024 * should be NULL. */ 1025 1026 /** 1027 * audit_log_start - obtain an audit buffer 1028 * @ctx: audit_context (may be NULL) 1029 * @gfp_mask: type of allocation 1030 * @type: audit message type 1031 * 1032 * Returns audit_buffer pointer on success or NULL on error. 1033 * 1034 * Obtain an audit buffer. This routine does locking to obtain the 1035 * audit buffer, but then no locking is required for calls to 1036 * audit_log_*format. If the task (ctx) is a task that is currently in a 1037 * syscall, then the syscall is marked as auditable and an audit record 1038 * will be written at syscall exit. If there is no associated task, then 1039 * task context (ctx) should be NULL. 1040 */ 1041 struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask, 1042 int type) 1043 { 1044 struct audit_buffer *ab = NULL; 1045 struct timespec t; 1046 unsigned int uninitialized_var(serial); 1047 int reserve; 1048 unsigned long timeout_start = jiffies; 1049 1050 if (!audit_initialized) 1051 return NULL; 1052 1053 if (unlikely(audit_filter_type(type))) 1054 return NULL; 1055 1056 if (gfp_mask & __GFP_WAIT) 1057 reserve = 0; 1058 else 1059 reserve = 5; /* Allow atomic callers to go up to five 1060 entries over the normal backlog limit */ 1061 1062 while (audit_backlog_limit 1063 && skb_queue_len(&audit_skb_queue) > audit_backlog_limit + reserve) { 1064 if (gfp_mask & __GFP_WAIT && audit_backlog_wait_time 1065 && time_before(jiffies, timeout_start + audit_backlog_wait_time)) { 1066 1067 /* Wait for auditd to drain the queue a little */ 1068 DECLARE_WAITQUEUE(wait, current); 1069 set_current_state(TASK_INTERRUPTIBLE); 1070 add_wait_queue(&audit_backlog_wait, &wait); 1071 1072 if (audit_backlog_limit && 1073 skb_queue_len(&audit_skb_queue) > audit_backlog_limit) 1074 schedule_timeout(timeout_start + audit_backlog_wait_time - jiffies); 1075 1076 __set_current_state(TASK_RUNNING); 1077 remove_wait_queue(&audit_backlog_wait, &wait); 1078 continue; 1079 } 1080 if (audit_rate_check() && printk_ratelimit()) 1081 printk(KERN_WARNING 1082 "audit: audit_backlog=%d > " 1083 "audit_backlog_limit=%d\n", 1084 skb_queue_len(&audit_skb_queue), 1085 audit_backlog_limit); 1086 audit_log_lost("backlog limit exceeded"); 1087 audit_backlog_wait_time = audit_backlog_wait_overflow; 1088 wake_up(&audit_backlog_wait); 1089 return NULL; 1090 } 1091 1092 ab = audit_buffer_alloc(ctx, gfp_mask, type); 1093 if (!ab) { 1094 audit_log_lost("out of memory in audit_log_start"); 1095 return NULL; 1096 } 1097 1098 audit_get_stamp(ab->ctx, &t, &serial); 1099 1100 audit_log_format(ab, "audit(%lu.%03lu:%u): ", 1101 t.tv_sec, t.tv_nsec/1000000, serial); 1102 return ab; 1103 } 1104 1105 /** 1106 * audit_expand - expand skb in the audit buffer 1107 * @ab: audit_buffer 1108 * @extra: space to add at tail of the skb 1109 * 1110 * Returns 0 (no space) on failed expansion, or available space if 1111 * successful. 1112 */ 1113 static inline int audit_expand(struct audit_buffer *ab, int extra) 1114 { 1115 struct sk_buff *skb = ab->skb; 1116 int oldtail = skb_tailroom(skb); 1117 int ret = pskb_expand_head(skb, 0, extra, ab->gfp_mask); 1118 int newtail = skb_tailroom(skb); 1119 1120 if (ret < 0) { 1121 audit_log_lost("out of memory in audit_expand"); 1122 return 0; 1123 } 1124 1125 skb->truesize += newtail - oldtail; 1126 return newtail; 1127 } 1128 1129 /* 1130 * Format an audit message into the audit buffer. If there isn't enough 1131 * room in the audit buffer, more room will be allocated and vsnprint 1132 * will be called a second time. Currently, we assume that a printk 1133 * can't format message larger than 1024 bytes, so we don't either. 1134 */ 1135 static void audit_log_vformat(struct audit_buffer *ab, const char *fmt, 1136 va_list args) 1137 { 1138 int len, avail; 1139 struct sk_buff *skb; 1140 va_list args2; 1141 1142 if (!ab) 1143 return; 1144 1145 BUG_ON(!ab->skb); 1146 skb = ab->skb; 1147 avail = skb_tailroom(skb); 1148 if (avail == 0) { 1149 avail = audit_expand(ab, AUDIT_BUFSIZ); 1150 if (!avail) 1151 goto out; 1152 } 1153 va_copy(args2, args); 1154 len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args); 1155 if (len >= avail) { 1156 /* The printk buffer is 1024 bytes long, so if we get 1157 * here and AUDIT_BUFSIZ is at least 1024, then we can 1158 * log everything that printk could have logged. */ 1159 avail = audit_expand(ab, 1160 max_t(unsigned, AUDIT_BUFSIZ, 1+len-avail)); 1161 if (!avail) 1162 goto out; 1163 len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args2); 1164 } 1165 va_end(args2); 1166 if (len > 0) 1167 skb_put(skb, len); 1168 out: 1169 return; 1170 } 1171 1172 /** 1173 * audit_log_format - format a message into the audit buffer. 1174 * @ab: audit_buffer 1175 * @fmt: format string 1176 * @...: optional parameters matching @fmt string 1177 * 1178 * All the work is done in audit_log_vformat. 1179 */ 1180 void audit_log_format(struct audit_buffer *ab, const char *fmt, ...) 1181 { 1182 va_list args; 1183 1184 if (!ab) 1185 return; 1186 va_start(args, fmt); 1187 audit_log_vformat(ab, fmt, args); 1188 va_end(args); 1189 } 1190 1191 /** 1192 * audit_log_hex - convert a buffer to hex and append it to the audit skb 1193 * @ab: the audit_buffer 1194 * @buf: buffer to convert to hex 1195 * @len: length of @buf to be converted 1196 * 1197 * No return value; failure to expand is silently ignored. 1198 * 1199 * This function will take the passed buf and convert it into a string of 1200 * ascii hex digits. The new string is placed onto the skb. 1201 */ 1202 void audit_log_hex(struct audit_buffer *ab, const unsigned char *buf, 1203 size_t len) 1204 { 1205 int i, avail, new_len; 1206 unsigned char *ptr; 1207 struct sk_buff *skb; 1208 static const unsigned char *hex = "0123456789ABCDEF"; 1209 1210 if (!ab) 1211 return; 1212 1213 BUG_ON(!ab->skb); 1214 skb = ab->skb; 1215 avail = skb_tailroom(skb); 1216 new_len = len<<1; 1217 if (new_len >= avail) { 1218 /* Round the buffer request up to the next multiple */ 1219 new_len = AUDIT_BUFSIZ*(((new_len-avail)/AUDIT_BUFSIZ) + 1); 1220 avail = audit_expand(ab, new_len); 1221 if (!avail) 1222 return; 1223 } 1224 1225 ptr = skb_tail_pointer(skb); 1226 for (i=0; i<len; i++) { 1227 *ptr++ = hex[(buf[i] & 0xF0)>>4]; /* Upper nibble */ 1228 *ptr++ = hex[buf[i] & 0x0F]; /* Lower nibble */ 1229 } 1230 *ptr = 0; 1231 skb_put(skb, len << 1); /* new string is twice the old string */ 1232 } 1233 1234 /* 1235 * Format a string of no more than slen characters into the audit buffer, 1236 * enclosed in quote marks. 1237 */ 1238 static void audit_log_n_string(struct audit_buffer *ab, size_t slen, 1239 const char *string) 1240 { 1241 int avail, new_len; 1242 unsigned char *ptr; 1243 struct sk_buff *skb; 1244 1245 if (!ab) 1246 return; 1247 1248 BUG_ON(!ab->skb); 1249 skb = ab->skb; 1250 avail = skb_tailroom(skb); 1251 new_len = slen + 3; /* enclosing quotes + null terminator */ 1252 if (new_len > avail) { 1253 avail = audit_expand(ab, new_len); 1254 if (!avail) 1255 return; 1256 } 1257 ptr = skb_tail_pointer(skb); 1258 *ptr++ = '"'; 1259 memcpy(ptr, string, slen); 1260 ptr += slen; 1261 *ptr++ = '"'; 1262 *ptr = 0; 1263 skb_put(skb, slen + 2); /* don't include null terminator */ 1264 } 1265 1266 /** 1267 * audit_string_contains_control - does a string need to be logged in hex 1268 * @string: string to be checked 1269 * @len: max length of the string to check 1270 */ 1271 int audit_string_contains_control(const char *string, size_t len) 1272 { 1273 const unsigned char *p; 1274 for (p = string; p < (const unsigned char *)string + len && *p; p++) { 1275 if (*p == '"' || *p < 0x21 || *p > 0x7f) 1276 return 1; 1277 } 1278 return 0; 1279 } 1280 1281 /** 1282 * audit_log_n_untrustedstring - log a string that may contain random characters 1283 * @ab: audit_buffer 1284 * @len: length of string (not including trailing null) 1285 * @string: string to be logged 1286 * 1287 * This code will escape a string that is passed to it if the string 1288 * contains a control character, unprintable character, double quote mark, 1289 * or a space. Unescaped strings will start and end with a double quote mark. 1290 * Strings that are escaped are printed in hex (2 digits per char). 1291 * 1292 * The caller specifies the number of characters in the string to log, which may 1293 * or may not be the entire string. 1294 */ 1295 void audit_log_n_untrustedstring(struct audit_buffer *ab, size_t len, 1296 const char *string) 1297 { 1298 if (audit_string_contains_control(string, len)) 1299 audit_log_hex(ab, string, len); 1300 else 1301 audit_log_n_string(ab, len, string); 1302 } 1303 1304 /** 1305 * audit_log_untrustedstring - log a string that may contain random characters 1306 * @ab: audit_buffer 1307 * @string: string to be logged 1308 * 1309 * Same as audit_log_n_untrustedstring(), except that strlen is used to 1310 * determine string length. 1311 */ 1312 void audit_log_untrustedstring(struct audit_buffer *ab, const char *string) 1313 { 1314 audit_log_n_untrustedstring(ab, strlen(string), string); 1315 } 1316 1317 /* This is a helper-function to print the escaped d_path */ 1318 void audit_log_d_path(struct audit_buffer *ab, const char *prefix, 1319 struct path *path) 1320 { 1321 char *p, *pathname; 1322 1323 if (prefix) 1324 audit_log_format(ab, " %s", prefix); 1325 1326 /* We will allow 11 spaces for ' (deleted)' to be appended */ 1327 pathname = kmalloc(PATH_MAX+11, ab->gfp_mask); 1328 if (!pathname) { 1329 audit_log_format(ab, "<no memory>"); 1330 return; 1331 } 1332 p = d_path(path, pathname, PATH_MAX+11); 1333 if (IS_ERR(p)) { /* Should never happen since we send PATH_MAX */ 1334 /* FIXME: can we save some information here? */ 1335 audit_log_format(ab, "<too long>"); 1336 } else 1337 audit_log_untrustedstring(ab, p); 1338 kfree(pathname); 1339 } 1340 1341 /** 1342 * audit_log_end - end one audit record 1343 * @ab: the audit_buffer 1344 * 1345 * The netlink_* functions cannot be called inside an irq context, so 1346 * the audit buffer is placed on a queue and a tasklet is scheduled to 1347 * remove them from the queue outside the irq context. May be called in 1348 * any context. 1349 */ 1350 void audit_log_end(struct audit_buffer *ab) 1351 { 1352 if (!ab) 1353 return; 1354 if (!audit_rate_check()) { 1355 audit_log_lost("rate limit exceeded"); 1356 } else { 1357 struct nlmsghdr *nlh = nlmsg_hdr(ab->skb); 1358 if (audit_pid) { 1359 nlh->nlmsg_len = ab->skb->len - NLMSG_SPACE(0); 1360 skb_queue_tail(&audit_skb_queue, ab->skb); 1361 ab->skb = NULL; 1362 wake_up_interruptible(&kauditd_wait); 1363 } else if (nlh->nlmsg_type != AUDIT_EOE) { 1364 if (printk_ratelimit()) { 1365 printk(KERN_NOTICE "type=%d %s\n", 1366 nlh->nlmsg_type, 1367 ab->skb->data + NLMSG_SPACE(0)); 1368 } else 1369 audit_log_lost("printk limit exceeded\n"); 1370 } 1371 } 1372 audit_buffer_free(ab); 1373 } 1374 1375 /** 1376 * audit_log - Log an audit record 1377 * @ctx: audit context 1378 * @gfp_mask: type of allocation 1379 * @type: audit message type 1380 * @fmt: format string to use 1381 * @...: variable parameters matching the format string 1382 * 1383 * This is a convenience function that calls audit_log_start, 1384 * audit_log_vformat, and audit_log_end. It may be called 1385 * in any context. 1386 */ 1387 void audit_log(struct audit_context *ctx, gfp_t gfp_mask, int type, 1388 const char *fmt, ...) 1389 { 1390 struct audit_buffer *ab; 1391 va_list args; 1392 1393 ab = audit_log_start(ctx, gfp_mask, type); 1394 if (ab) { 1395 va_start(args, fmt); 1396 audit_log_vformat(ab, fmt, args); 1397 va_end(args); 1398 audit_log_end(ab); 1399 } 1400 } 1401 1402 EXPORT_SYMBOL(audit_log_start); 1403 EXPORT_SYMBOL(audit_log_end); 1404 EXPORT_SYMBOL(audit_log_format); 1405 EXPORT_SYMBOL(audit_log); 1406