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/slab.h> 50 #include <linux/err.h> 51 #include <linux/kthread.h> 52 53 #include <linux/audit.h> 54 55 #include <net/sock.h> 56 #include <net/netlink.h> 57 #include <linux/skbuff.h> 58 #include <linux/netlink.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 == AUDIT_INITIALIZED. 65 * (Initialization happens after skb_init is called.) */ 66 #define AUDIT_DISABLED -1 67 #define AUDIT_UNINITIALIZED 0 68 #define AUDIT_INITIALIZED 1 69 static int audit_initialized; 70 71 #define AUDIT_OFF 0 72 #define AUDIT_ON 1 73 #define AUDIT_LOCKED 2 74 int audit_enabled; 75 int audit_ever_enabled; 76 77 /* Default state when kernel boots without any parameters. */ 78 static int audit_default; 79 80 /* If auditing cannot proceed, audit_failure selects what happens. */ 81 static int audit_failure = AUDIT_FAIL_PRINTK; 82 83 /* 84 * If audit records are to be written to the netlink socket, audit_pid 85 * contains the pid of the auditd process and audit_nlk_pid contains 86 * the pid to use to send netlink messages to that process. 87 */ 88 int audit_pid; 89 static int audit_nlk_pid; 90 91 /* If audit_rate_limit is non-zero, limit the rate of sending audit records 92 * to that number per second. This prevents DoS attacks, but results in 93 * audit records being dropped. */ 94 static int audit_rate_limit; 95 96 /* Number of outstanding audit_buffers allowed. */ 97 static int audit_backlog_limit = 64; 98 static int audit_backlog_wait_time = 60 * HZ; 99 static int audit_backlog_wait_overflow = 0; 100 101 /* The identity of the user shutting down the audit system. */ 102 uid_t audit_sig_uid = -1; 103 pid_t audit_sig_pid = -1; 104 u32 audit_sig_sid = 0; 105 106 /* Records can be lost in several ways: 107 0) [suppressed in audit_alloc] 108 1) out of memory in audit_log_start [kmalloc of struct audit_buffer] 109 2) out of memory in audit_log_move [alloc_skb] 110 3) suppressed due to audit_rate_limit 111 4) suppressed due to audit_backlog_limit 112 */ 113 static atomic_t audit_lost = ATOMIC_INIT(0); 114 115 /* The netlink socket. */ 116 static struct sock *audit_sock; 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 /* queue of skbs to send to auditd when/if it comes back */ 130 static struct sk_buff_head audit_skb_hold_queue; 131 static struct task_struct *kauditd_task; 132 static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait); 133 static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait); 134 135 /* Serialize requests from userspace. */ 136 DEFINE_MUTEX(audit_cmd_mutex); 137 138 /* AUDIT_BUFSIZ is the size of the temporary buffer used for formatting 139 * audit records. Since printk uses a 1024 byte buffer, this buffer 140 * should be at least that large. */ 141 #define AUDIT_BUFSIZ 1024 142 143 /* AUDIT_MAXFREE is the number of empty audit_buffers we keep on the 144 * audit_freelist. Doing so eliminates many kmalloc/kfree calls. */ 145 #define AUDIT_MAXFREE (2*NR_CPUS) 146 147 /* The audit_buffer is used when formatting an audit record. The caller 148 * locks briefly to get the record off the freelist or to allocate the 149 * buffer, and locks briefly to send the buffer to the netlink layer or 150 * to place it on a transmit queue. Multiple audit_buffers can be in 151 * use simultaneously. */ 152 struct audit_buffer { 153 struct list_head list; 154 struct sk_buff *skb; /* formatted skb ready to send */ 155 struct audit_context *ctx; /* NULL or associated context */ 156 gfp_t gfp_mask; 157 }; 158 159 struct audit_reply { 160 int pid; 161 struct sk_buff *skb; 162 }; 163 164 static void audit_set_pid(struct audit_buffer *ab, pid_t pid) 165 { 166 if (ab) { 167 struct nlmsghdr *nlh = nlmsg_hdr(ab->skb); 168 nlh->nlmsg_pid = pid; 169 } 170 } 171 172 void audit_panic(const char *message) 173 { 174 switch (audit_failure) 175 { 176 case AUDIT_FAIL_SILENT: 177 break; 178 case AUDIT_FAIL_PRINTK: 179 if (printk_ratelimit()) 180 printk(KERN_ERR "audit: %s\n", message); 181 break; 182 case AUDIT_FAIL_PANIC: 183 /* test audit_pid since printk is always losey, why bother? */ 184 if (audit_pid) 185 panic("audit: %s\n", message); 186 break; 187 } 188 } 189 190 static inline int audit_rate_check(void) 191 { 192 static unsigned long last_check = 0; 193 static int messages = 0; 194 static DEFINE_SPINLOCK(lock); 195 unsigned long flags; 196 unsigned long now; 197 unsigned long elapsed; 198 int retval = 0; 199 200 if (!audit_rate_limit) return 1; 201 202 spin_lock_irqsave(&lock, flags); 203 if (++messages < audit_rate_limit) { 204 retval = 1; 205 } else { 206 now = jiffies; 207 elapsed = now - last_check; 208 if (elapsed > HZ) { 209 last_check = now; 210 messages = 0; 211 retval = 1; 212 } 213 } 214 spin_unlock_irqrestore(&lock, flags); 215 216 return retval; 217 } 218 219 /** 220 * audit_log_lost - conditionally log lost audit message event 221 * @message: the message stating reason for lost audit message 222 * 223 * Emit at least 1 message per second, even if audit_rate_check is 224 * throttling. 225 * Always increment the lost messages counter. 226 */ 227 void audit_log_lost(const char *message) 228 { 229 static unsigned long last_msg = 0; 230 static DEFINE_SPINLOCK(lock); 231 unsigned long flags; 232 unsigned long now; 233 int print; 234 235 atomic_inc(&audit_lost); 236 237 print = (audit_failure == AUDIT_FAIL_PANIC || !audit_rate_limit); 238 239 if (!print) { 240 spin_lock_irqsave(&lock, flags); 241 now = jiffies; 242 if (now - last_msg > HZ) { 243 print = 1; 244 last_msg = now; 245 } 246 spin_unlock_irqrestore(&lock, flags); 247 } 248 249 if (print) { 250 if (printk_ratelimit()) 251 printk(KERN_WARNING 252 "audit: audit_lost=%d audit_rate_limit=%d " 253 "audit_backlog_limit=%d\n", 254 atomic_read(&audit_lost), 255 audit_rate_limit, 256 audit_backlog_limit); 257 audit_panic(message); 258 } 259 } 260 261 static int audit_log_config_change(char *function_name, int new, int old, 262 uid_t loginuid, u32 sessionid, u32 sid, 263 int allow_changes) 264 { 265 struct audit_buffer *ab; 266 int rc = 0; 267 268 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE); 269 audit_log_format(ab, "%s=%d old=%d auid=%u ses=%u", function_name, new, 270 old, loginuid, sessionid); 271 if (sid) { 272 char *ctx = NULL; 273 u32 len; 274 275 rc = security_secid_to_secctx(sid, &ctx, &len); 276 if (rc) { 277 audit_log_format(ab, " sid=%u", sid); 278 allow_changes = 0; /* Something weird, deny request */ 279 } else { 280 audit_log_format(ab, " subj=%s", ctx); 281 security_release_secctx(ctx, len); 282 } 283 } 284 audit_log_format(ab, " res=%d", allow_changes); 285 audit_log_end(ab); 286 return rc; 287 } 288 289 static int audit_do_config_change(char *function_name, int *to_change, 290 int new, uid_t loginuid, u32 sessionid, 291 u32 sid) 292 { 293 int allow_changes, rc = 0, old = *to_change; 294 295 /* check if we are locked */ 296 if (audit_enabled == AUDIT_LOCKED) 297 allow_changes = 0; 298 else 299 allow_changes = 1; 300 301 if (audit_enabled != AUDIT_OFF) { 302 rc = audit_log_config_change(function_name, new, old, loginuid, 303 sessionid, sid, allow_changes); 304 if (rc) 305 allow_changes = 0; 306 } 307 308 /* If we are allowed, make the change */ 309 if (allow_changes == 1) 310 *to_change = new; 311 /* Not allowed, update reason */ 312 else if (rc == 0) 313 rc = -EPERM; 314 return rc; 315 } 316 317 static int audit_set_rate_limit(int limit, uid_t loginuid, u32 sessionid, 318 u32 sid) 319 { 320 return audit_do_config_change("audit_rate_limit", &audit_rate_limit, 321 limit, loginuid, sessionid, sid); 322 } 323 324 static int audit_set_backlog_limit(int limit, uid_t loginuid, u32 sessionid, 325 u32 sid) 326 { 327 return audit_do_config_change("audit_backlog_limit", &audit_backlog_limit, 328 limit, loginuid, sessionid, sid); 329 } 330 331 static int audit_set_enabled(int state, uid_t loginuid, u32 sessionid, u32 sid) 332 { 333 int rc; 334 if (state < AUDIT_OFF || state > AUDIT_LOCKED) 335 return -EINVAL; 336 337 rc = audit_do_config_change("audit_enabled", &audit_enabled, state, 338 loginuid, sessionid, sid); 339 340 if (!rc) 341 audit_ever_enabled |= !!state; 342 343 return rc; 344 } 345 346 static int audit_set_failure(int state, uid_t loginuid, u32 sessionid, u32 sid) 347 { 348 if (state != AUDIT_FAIL_SILENT 349 && state != AUDIT_FAIL_PRINTK 350 && state != AUDIT_FAIL_PANIC) 351 return -EINVAL; 352 353 return audit_do_config_change("audit_failure", &audit_failure, state, 354 loginuid, sessionid, sid); 355 } 356 357 /* 358 * Queue skbs to be sent to auditd when/if it comes back. These skbs should 359 * already have been sent via prink/syslog and so if these messages are dropped 360 * it is not a huge concern since we already passed the audit_log_lost() 361 * notification and stuff. This is just nice to get audit messages during 362 * boot before auditd is running or messages generated while auditd is stopped. 363 * This only holds messages is audit_default is set, aka booting with audit=1 364 * or building your kernel that way. 365 */ 366 static void audit_hold_skb(struct sk_buff *skb) 367 { 368 if (audit_default && 369 skb_queue_len(&audit_skb_hold_queue) < audit_backlog_limit) 370 skb_queue_tail(&audit_skb_hold_queue, skb); 371 else 372 kfree_skb(skb); 373 } 374 375 /* 376 * For one reason or another this nlh isn't getting delivered to the userspace 377 * audit daemon, just send it to printk. 378 */ 379 static void audit_printk_skb(struct sk_buff *skb) 380 { 381 struct nlmsghdr *nlh = nlmsg_hdr(skb); 382 char *data = NLMSG_DATA(nlh); 383 384 if (nlh->nlmsg_type != AUDIT_EOE) { 385 if (printk_ratelimit()) 386 printk(KERN_NOTICE "type=%d %s\n", nlh->nlmsg_type, data); 387 else 388 audit_log_lost("printk limit exceeded\n"); 389 } 390 391 audit_hold_skb(skb); 392 } 393 394 static void kauditd_send_skb(struct sk_buff *skb) 395 { 396 int err; 397 /* take a reference in case we can't send it and we want to hold it */ 398 skb_get(skb); 399 err = netlink_unicast(audit_sock, skb, audit_nlk_pid, 0); 400 if (err < 0) { 401 BUG_ON(err != -ECONNREFUSED); /* Shouldn't happen */ 402 printk(KERN_ERR "audit: *NO* daemon at audit_pid=%d\n", audit_pid); 403 audit_log_lost("auditd disappeared\n"); 404 audit_pid = 0; 405 /* we might get lucky and get this in the next auditd */ 406 audit_hold_skb(skb); 407 } else 408 /* drop the extra reference if sent ok */ 409 consume_skb(skb); 410 } 411 412 static int kauditd_thread(void *dummy) 413 { 414 struct sk_buff *skb; 415 416 set_freezable(); 417 while (!kthread_should_stop()) { 418 /* 419 * if auditd just started drain the queue of messages already 420 * sent to syslog/printk. remember loss here is ok. we already 421 * called audit_log_lost() if it didn't go out normally. so the 422 * race between the skb_dequeue and the next check for audit_pid 423 * doesn't matter. 424 * 425 * if you ever find kauditd to be too slow we can get a perf win 426 * by doing our own locking and keeping better track if there 427 * are messages in this queue. I don't see the need now, but 428 * in 5 years when I want to play with this again I'll see this 429 * note and still have no friggin idea what i'm thinking today. 430 */ 431 if (audit_default && audit_pid) { 432 skb = skb_dequeue(&audit_skb_hold_queue); 433 if (unlikely(skb)) { 434 while (skb && audit_pid) { 435 kauditd_send_skb(skb); 436 skb = skb_dequeue(&audit_skb_hold_queue); 437 } 438 } 439 } 440 441 skb = skb_dequeue(&audit_skb_queue); 442 wake_up(&audit_backlog_wait); 443 if (skb) { 444 if (audit_pid) 445 kauditd_send_skb(skb); 446 else 447 audit_printk_skb(skb); 448 } else { 449 DECLARE_WAITQUEUE(wait, current); 450 set_current_state(TASK_INTERRUPTIBLE); 451 add_wait_queue(&kauditd_wait, &wait); 452 453 if (!skb_queue_len(&audit_skb_queue)) { 454 try_to_freeze(); 455 schedule(); 456 } 457 458 __set_current_state(TASK_RUNNING); 459 remove_wait_queue(&kauditd_wait, &wait); 460 } 461 } 462 return 0; 463 } 464 465 static int audit_prepare_user_tty(pid_t pid, uid_t loginuid, u32 sessionid) 466 { 467 struct task_struct *tsk; 468 int err; 469 470 rcu_read_lock(); 471 tsk = find_task_by_vpid(pid); 472 if (!tsk) { 473 rcu_read_unlock(); 474 return -ESRCH; 475 } 476 get_task_struct(tsk); 477 rcu_read_unlock(); 478 err = tty_audit_push_task(tsk, loginuid, sessionid); 479 put_task_struct(tsk); 480 return err; 481 } 482 483 int audit_send_list(void *_dest) 484 { 485 struct audit_netlink_list *dest = _dest; 486 int pid = dest->pid; 487 struct sk_buff *skb; 488 489 /* wait for parent to finish and send an ACK */ 490 mutex_lock(&audit_cmd_mutex); 491 mutex_unlock(&audit_cmd_mutex); 492 493 while ((skb = __skb_dequeue(&dest->q)) != NULL) 494 netlink_unicast(audit_sock, skb, pid, 0); 495 496 kfree(dest); 497 498 return 0; 499 } 500 501 struct sk_buff *audit_make_reply(int pid, int seq, int type, int done, 502 int multi, const void *payload, int size) 503 { 504 struct sk_buff *skb; 505 struct nlmsghdr *nlh; 506 void *data; 507 int flags = multi ? NLM_F_MULTI : 0; 508 int t = done ? NLMSG_DONE : type; 509 510 skb = nlmsg_new(size, GFP_KERNEL); 511 if (!skb) 512 return NULL; 513 514 nlh = NLMSG_NEW(skb, pid, seq, t, size, flags); 515 data = NLMSG_DATA(nlh); 516 memcpy(data, payload, size); 517 return skb; 518 519 nlmsg_failure: /* Used by NLMSG_NEW */ 520 if (skb) 521 kfree_skb(skb); 522 return NULL; 523 } 524 525 static int audit_send_reply_thread(void *arg) 526 { 527 struct audit_reply *reply = (struct audit_reply *)arg; 528 529 mutex_lock(&audit_cmd_mutex); 530 mutex_unlock(&audit_cmd_mutex); 531 532 /* Ignore failure. It'll only happen if the sender goes away, 533 because our timeout is set to infinite. */ 534 netlink_unicast(audit_sock, reply->skb, reply->pid, 0); 535 kfree(reply); 536 return 0; 537 } 538 /** 539 * audit_send_reply - send an audit reply message via netlink 540 * @pid: process id to send reply to 541 * @seq: sequence number 542 * @type: audit message type 543 * @done: done (last) flag 544 * @multi: multi-part message flag 545 * @payload: payload data 546 * @size: payload size 547 * 548 * Allocates an skb, builds the netlink message, and sends it to the pid. 549 * No failure notifications. 550 */ 551 static void audit_send_reply(int pid, int seq, int type, int done, int multi, 552 const void *payload, int size) 553 { 554 struct sk_buff *skb; 555 struct task_struct *tsk; 556 struct audit_reply *reply = kmalloc(sizeof(struct audit_reply), 557 GFP_KERNEL); 558 559 if (!reply) 560 return; 561 562 skb = audit_make_reply(pid, seq, type, done, multi, payload, size); 563 if (!skb) 564 goto out; 565 566 reply->pid = pid; 567 reply->skb = skb; 568 569 tsk = kthread_run(audit_send_reply_thread, reply, "audit_send_reply"); 570 if (!IS_ERR(tsk)) 571 return; 572 kfree_skb(skb); 573 out: 574 kfree(reply); 575 } 576 577 /* 578 * Check for appropriate CAP_AUDIT_ capabilities on incoming audit 579 * control messages. 580 */ 581 static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type) 582 { 583 int err = 0; 584 585 switch (msg_type) { 586 case AUDIT_GET: 587 case AUDIT_LIST: 588 case AUDIT_LIST_RULES: 589 case AUDIT_SET: 590 case AUDIT_ADD: 591 case AUDIT_ADD_RULE: 592 case AUDIT_DEL: 593 case AUDIT_DEL_RULE: 594 case AUDIT_SIGNAL_INFO: 595 case AUDIT_TTY_GET: 596 case AUDIT_TTY_SET: 597 case AUDIT_TRIM: 598 case AUDIT_MAKE_EQUIV: 599 if (security_netlink_recv(skb, CAP_AUDIT_CONTROL)) 600 err = -EPERM; 601 break; 602 case AUDIT_USER: 603 case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG: 604 case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2: 605 if (security_netlink_recv(skb, CAP_AUDIT_WRITE)) 606 err = -EPERM; 607 break; 608 default: /* bad msg */ 609 err = -EINVAL; 610 } 611 612 return err; 613 } 614 615 static int audit_log_common_recv_msg(struct audit_buffer **ab, u16 msg_type, 616 u32 pid, u32 uid, uid_t auid, u32 ses, 617 u32 sid) 618 { 619 int rc = 0; 620 char *ctx = NULL; 621 u32 len; 622 623 if (!audit_enabled) { 624 *ab = NULL; 625 return rc; 626 } 627 628 *ab = audit_log_start(NULL, GFP_KERNEL, msg_type); 629 audit_log_format(*ab, "user pid=%d uid=%u auid=%u ses=%u", 630 pid, uid, auid, ses); 631 if (sid) { 632 rc = security_secid_to_secctx(sid, &ctx, &len); 633 if (rc) 634 audit_log_format(*ab, " ssid=%u", sid); 635 else { 636 audit_log_format(*ab, " subj=%s", ctx); 637 security_release_secctx(ctx, len); 638 } 639 } 640 641 return rc; 642 } 643 644 static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) 645 { 646 u32 uid, pid, seq, sid; 647 void *data; 648 struct audit_status *status_get, status_set; 649 int err; 650 struct audit_buffer *ab; 651 u16 msg_type = nlh->nlmsg_type; 652 uid_t loginuid; /* loginuid of sender */ 653 u32 sessionid; 654 struct audit_sig_info *sig_data; 655 char *ctx = NULL; 656 u32 len; 657 658 err = audit_netlink_ok(skb, msg_type); 659 if (err) 660 return err; 661 662 /* As soon as there's any sign of userspace auditd, 663 * start kauditd to talk to it */ 664 if (!kauditd_task) 665 kauditd_task = kthread_run(kauditd_thread, NULL, "kauditd"); 666 if (IS_ERR(kauditd_task)) { 667 err = PTR_ERR(kauditd_task); 668 kauditd_task = NULL; 669 return err; 670 } 671 672 pid = NETLINK_CREDS(skb)->pid; 673 uid = NETLINK_CREDS(skb)->uid; 674 loginuid = NETLINK_CB(skb).loginuid; 675 sessionid = NETLINK_CB(skb).sessionid; 676 sid = NETLINK_CB(skb).sid; 677 seq = nlh->nlmsg_seq; 678 data = NLMSG_DATA(nlh); 679 680 switch (msg_type) { 681 case AUDIT_GET: 682 status_set.enabled = audit_enabled; 683 status_set.failure = audit_failure; 684 status_set.pid = audit_pid; 685 status_set.rate_limit = audit_rate_limit; 686 status_set.backlog_limit = audit_backlog_limit; 687 status_set.lost = atomic_read(&audit_lost); 688 status_set.backlog = skb_queue_len(&audit_skb_queue); 689 audit_send_reply(NETLINK_CB(skb).pid, seq, AUDIT_GET, 0, 0, 690 &status_set, sizeof(status_set)); 691 break; 692 case AUDIT_SET: 693 if (nlh->nlmsg_len < sizeof(struct audit_status)) 694 return -EINVAL; 695 status_get = (struct audit_status *)data; 696 if (status_get->mask & AUDIT_STATUS_ENABLED) { 697 err = audit_set_enabled(status_get->enabled, 698 loginuid, sessionid, sid); 699 if (err < 0) 700 return err; 701 } 702 if (status_get->mask & AUDIT_STATUS_FAILURE) { 703 err = audit_set_failure(status_get->failure, 704 loginuid, sessionid, sid); 705 if (err < 0) 706 return err; 707 } 708 if (status_get->mask & AUDIT_STATUS_PID) { 709 int new_pid = status_get->pid; 710 711 if (audit_enabled != AUDIT_OFF) 712 audit_log_config_change("audit_pid", new_pid, 713 audit_pid, loginuid, 714 sessionid, sid, 1); 715 716 audit_pid = new_pid; 717 audit_nlk_pid = NETLINK_CB(skb).pid; 718 } 719 if (status_get->mask & AUDIT_STATUS_RATE_LIMIT) { 720 err = audit_set_rate_limit(status_get->rate_limit, 721 loginuid, sessionid, sid); 722 if (err < 0) 723 return err; 724 } 725 if (status_get->mask & AUDIT_STATUS_BACKLOG_LIMIT) 726 err = audit_set_backlog_limit(status_get->backlog_limit, 727 loginuid, sessionid, sid); 728 break; 729 case AUDIT_USER: 730 case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG: 731 case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2: 732 if (!audit_enabled && msg_type != AUDIT_USER_AVC) 733 return 0; 734 735 err = audit_filter_user(&NETLINK_CB(skb)); 736 if (err == 1) { 737 err = 0; 738 if (msg_type == AUDIT_USER_TTY) { 739 err = audit_prepare_user_tty(pid, loginuid, 740 sessionid); 741 if (err) 742 break; 743 } 744 audit_log_common_recv_msg(&ab, msg_type, pid, uid, 745 loginuid, sessionid, sid); 746 747 if (msg_type != AUDIT_USER_TTY) 748 audit_log_format(ab, " msg='%.1024s'", 749 (char *)data); 750 else { 751 int size; 752 753 audit_log_format(ab, " msg="); 754 size = nlmsg_len(nlh); 755 if (size > 0 && 756 ((unsigned char *)data)[size - 1] == '\0') 757 size--; 758 audit_log_n_untrustedstring(ab, data, size); 759 } 760 audit_set_pid(ab, pid); 761 audit_log_end(ab); 762 } 763 break; 764 case AUDIT_ADD: 765 case AUDIT_DEL: 766 if (nlmsg_len(nlh) < sizeof(struct audit_rule)) 767 return -EINVAL; 768 if (audit_enabled == AUDIT_LOCKED) { 769 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE, pid, 770 uid, loginuid, sessionid, sid); 771 772 audit_log_format(ab, " audit_enabled=%d res=0", 773 audit_enabled); 774 audit_log_end(ab); 775 return -EPERM; 776 } 777 /* fallthrough */ 778 case AUDIT_LIST: 779 err = audit_receive_filter(msg_type, NETLINK_CB(skb).pid, 780 uid, seq, data, nlmsg_len(nlh), 781 loginuid, sessionid, sid); 782 break; 783 case AUDIT_ADD_RULE: 784 case AUDIT_DEL_RULE: 785 if (nlmsg_len(nlh) < sizeof(struct audit_rule_data)) 786 return -EINVAL; 787 if (audit_enabled == AUDIT_LOCKED) { 788 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE, pid, 789 uid, loginuid, sessionid, sid); 790 791 audit_log_format(ab, " audit_enabled=%d res=0", 792 audit_enabled); 793 audit_log_end(ab); 794 return -EPERM; 795 } 796 /* fallthrough */ 797 case AUDIT_LIST_RULES: 798 err = audit_receive_filter(msg_type, NETLINK_CB(skb).pid, 799 uid, seq, data, nlmsg_len(nlh), 800 loginuid, sessionid, sid); 801 break; 802 case AUDIT_TRIM: 803 audit_trim_trees(); 804 805 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE, pid, 806 uid, loginuid, sessionid, sid); 807 808 audit_log_format(ab, " op=trim res=1"); 809 audit_log_end(ab); 810 break; 811 case AUDIT_MAKE_EQUIV: { 812 void *bufp = data; 813 u32 sizes[2]; 814 size_t msglen = nlmsg_len(nlh); 815 char *old, *new; 816 817 err = -EINVAL; 818 if (msglen < 2 * sizeof(u32)) 819 break; 820 memcpy(sizes, bufp, 2 * sizeof(u32)); 821 bufp += 2 * sizeof(u32); 822 msglen -= 2 * sizeof(u32); 823 old = audit_unpack_string(&bufp, &msglen, sizes[0]); 824 if (IS_ERR(old)) { 825 err = PTR_ERR(old); 826 break; 827 } 828 new = audit_unpack_string(&bufp, &msglen, sizes[1]); 829 if (IS_ERR(new)) { 830 err = PTR_ERR(new); 831 kfree(old); 832 break; 833 } 834 /* OK, here comes... */ 835 err = audit_tag_tree(old, new); 836 837 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE, pid, 838 uid, loginuid, sessionid, sid); 839 840 audit_log_format(ab, " op=make_equiv old="); 841 audit_log_untrustedstring(ab, old); 842 audit_log_format(ab, " new="); 843 audit_log_untrustedstring(ab, new); 844 audit_log_format(ab, " res=%d", !err); 845 audit_log_end(ab); 846 kfree(old); 847 kfree(new); 848 break; 849 } 850 case AUDIT_SIGNAL_INFO: 851 len = 0; 852 if (audit_sig_sid) { 853 err = security_secid_to_secctx(audit_sig_sid, &ctx, &len); 854 if (err) 855 return err; 856 } 857 sig_data = kmalloc(sizeof(*sig_data) + len, GFP_KERNEL); 858 if (!sig_data) { 859 if (audit_sig_sid) 860 security_release_secctx(ctx, len); 861 return -ENOMEM; 862 } 863 sig_data->uid = audit_sig_uid; 864 sig_data->pid = audit_sig_pid; 865 if (audit_sig_sid) { 866 memcpy(sig_data->ctx, ctx, len); 867 security_release_secctx(ctx, len); 868 } 869 audit_send_reply(NETLINK_CB(skb).pid, seq, AUDIT_SIGNAL_INFO, 870 0, 0, sig_data, sizeof(*sig_data) + len); 871 kfree(sig_data); 872 break; 873 case AUDIT_TTY_GET: { 874 struct audit_tty_status s; 875 struct task_struct *tsk; 876 unsigned long flags; 877 878 rcu_read_lock(); 879 tsk = find_task_by_vpid(pid); 880 if (tsk && lock_task_sighand(tsk, &flags)) { 881 s.enabled = tsk->signal->audit_tty != 0; 882 unlock_task_sighand(tsk, &flags); 883 } else 884 err = -ESRCH; 885 rcu_read_unlock(); 886 887 if (!err) 888 audit_send_reply(NETLINK_CB(skb).pid, seq, 889 AUDIT_TTY_GET, 0, 0, &s, sizeof(s)); 890 break; 891 } 892 case AUDIT_TTY_SET: { 893 struct audit_tty_status *s; 894 struct task_struct *tsk; 895 unsigned long flags; 896 897 if (nlh->nlmsg_len < sizeof(struct audit_tty_status)) 898 return -EINVAL; 899 s = data; 900 if (s->enabled != 0 && s->enabled != 1) 901 return -EINVAL; 902 rcu_read_lock(); 903 tsk = find_task_by_vpid(pid); 904 if (tsk && lock_task_sighand(tsk, &flags)) { 905 tsk->signal->audit_tty = s->enabled != 0; 906 unlock_task_sighand(tsk, &flags); 907 } else 908 err = -ESRCH; 909 rcu_read_unlock(); 910 break; 911 } 912 default: 913 err = -EINVAL; 914 break; 915 } 916 917 return err < 0 ? err : 0; 918 } 919 920 /* 921 * Get message from skb. Each message is processed by audit_receive_msg. 922 * Malformed skbs with wrong length are discarded silently. 923 */ 924 static void audit_receive_skb(struct sk_buff *skb) 925 { 926 struct nlmsghdr *nlh; 927 /* 928 * len MUST be signed for NLMSG_NEXT to be able to dec it below 0 929 * if the nlmsg_len was not aligned 930 */ 931 int len; 932 int err; 933 934 nlh = nlmsg_hdr(skb); 935 len = skb->len; 936 937 while (NLMSG_OK(nlh, len)) { 938 err = audit_receive_msg(skb, nlh); 939 /* if err or if this message says it wants a response */ 940 if (err || (nlh->nlmsg_flags & NLM_F_ACK)) 941 netlink_ack(skb, nlh, err); 942 943 nlh = NLMSG_NEXT(nlh, len); 944 } 945 } 946 947 /* Receive messages from netlink socket. */ 948 static void audit_receive(struct sk_buff *skb) 949 { 950 mutex_lock(&audit_cmd_mutex); 951 audit_receive_skb(skb); 952 mutex_unlock(&audit_cmd_mutex); 953 } 954 955 /* Initialize audit support at boot time. */ 956 static int __init audit_init(void) 957 { 958 int i; 959 960 if (audit_initialized == AUDIT_DISABLED) 961 return 0; 962 963 printk(KERN_INFO "audit: initializing netlink socket (%s)\n", 964 audit_default ? "enabled" : "disabled"); 965 audit_sock = netlink_kernel_create(&init_net, NETLINK_AUDIT, 0, 966 audit_receive, NULL, THIS_MODULE); 967 if (!audit_sock) 968 audit_panic("cannot initialize netlink socket"); 969 else 970 audit_sock->sk_sndtimeo = MAX_SCHEDULE_TIMEOUT; 971 972 skb_queue_head_init(&audit_skb_queue); 973 skb_queue_head_init(&audit_skb_hold_queue); 974 audit_initialized = AUDIT_INITIALIZED; 975 audit_enabled = audit_default; 976 audit_ever_enabled |= !!audit_default; 977 978 audit_log(NULL, GFP_KERNEL, AUDIT_KERNEL, "initialized"); 979 980 for (i = 0; i < AUDIT_INODE_BUCKETS; i++) 981 INIT_LIST_HEAD(&audit_inode_hash[i]); 982 983 return 0; 984 } 985 __initcall(audit_init); 986 987 /* Process kernel command-line parameter at boot time. audit=0 or audit=1. */ 988 static int __init audit_enable(char *str) 989 { 990 audit_default = !!simple_strtol(str, NULL, 0); 991 if (!audit_default) 992 audit_initialized = AUDIT_DISABLED; 993 994 printk(KERN_INFO "audit: %s", audit_default ? "enabled" : "disabled"); 995 996 if (audit_initialized == AUDIT_INITIALIZED) { 997 audit_enabled = audit_default; 998 audit_ever_enabled |= !!audit_default; 999 } else if (audit_initialized == AUDIT_UNINITIALIZED) { 1000 printk(" (after initialization)"); 1001 } else { 1002 printk(" (until reboot)"); 1003 } 1004 printk("\n"); 1005 1006 return 1; 1007 } 1008 1009 __setup("audit=", audit_enable); 1010 1011 static void audit_buffer_free(struct audit_buffer *ab) 1012 { 1013 unsigned long flags; 1014 1015 if (!ab) 1016 return; 1017 1018 if (ab->skb) 1019 kfree_skb(ab->skb); 1020 1021 spin_lock_irqsave(&audit_freelist_lock, flags); 1022 if (audit_freelist_count > AUDIT_MAXFREE) 1023 kfree(ab); 1024 else { 1025 audit_freelist_count++; 1026 list_add(&ab->list, &audit_freelist); 1027 } 1028 spin_unlock_irqrestore(&audit_freelist_lock, flags); 1029 } 1030 1031 static struct audit_buffer * audit_buffer_alloc(struct audit_context *ctx, 1032 gfp_t gfp_mask, int type) 1033 { 1034 unsigned long flags; 1035 struct audit_buffer *ab = NULL; 1036 struct nlmsghdr *nlh; 1037 1038 spin_lock_irqsave(&audit_freelist_lock, flags); 1039 if (!list_empty(&audit_freelist)) { 1040 ab = list_entry(audit_freelist.next, 1041 struct audit_buffer, list); 1042 list_del(&ab->list); 1043 --audit_freelist_count; 1044 } 1045 spin_unlock_irqrestore(&audit_freelist_lock, flags); 1046 1047 if (!ab) { 1048 ab = kmalloc(sizeof(*ab), gfp_mask); 1049 if (!ab) 1050 goto err; 1051 } 1052 1053 ab->ctx = ctx; 1054 ab->gfp_mask = gfp_mask; 1055 1056 ab->skb = nlmsg_new(AUDIT_BUFSIZ, gfp_mask); 1057 if (!ab->skb) 1058 goto nlmsg_failure; 1059 1060 nlh = NLMSG_NEW(ab->skb, 0, 0, type, 0, 0); 1061 1062 return ab; 1063 1064 nlmsg_failure: /* Used by NLMSG_NEW */ 1065 kfree_skb(ab->skb); 1066 ab->skb = NULL; 1067 err: 1068 audit_buffer_free(ab); 1069 return NULL; 1070 } 1071 1072 /** 1073 * audit_serial - compute a serial number for the audit record 1074 * 1075 * Compute a serial number for the audit record. Audit records are 1076 * written to user-space as soon as they are generated, so a complete 1077 * audit record may be written in several pieces. The timestamp of the 1078 * record and this serial number are used by the user-space tools to 1079 * determine which pieces belong to the same audit record. The 1080 * (timestamp,serial) tuple is unique for each syscall and is live from 1081 * syscall entry to syscall exit. 1082 * 1083 * NOTE: Another possibility is to store the formatted records off the 1084 * audit context (for those records that have a context), and emit them 1085 * all at syscall exit. However, this could delay the reporting of 1086 * significant errors until syscall exit (or never, if the system 1087 * halts). 1088 */ 1089 unsigned int audit_serial(void) 1090 { 1091 static DEFINE_SPINLOCK(serial_lock); 1092 static unsigned int serial = 0; 1093 1094 unsigned long flags; 1095 unsigned int ret; 1096 1097 spin_lock_irqsave(&serial_lock, flags); 1098 do { 1099 ret = ++serial; 1100 } while (unlikely(!ret)); 1101 spin_unlock_irqrestore(&serial_lock, flags); 1102 1103 return ret; 1104 } 1105 1106 static inline void audit_get_stamp(struct audit_context *ctx, 1107 struct timespec *t, unsigned int *serial) 1108 { 1109 if (!ctx || !auditsc_get_stamp(ctx, t, serial)) { 1110 *t = CURRENT_TIME; 1111 *serial = audit_serial(); 1112 } 1113 } 1114 1115 /* Obtain an audit buffer. This routine does locking to obtain the 1116 * audit buffer, but then no locking is required for calls to 1117 * audit_log_*format. If the tsk is a task that is currently in a 1118 * syscall, then the syscall is marked as auditable and an audit record 1119 * will be written at syscall exit. If there is no associated task, tsk 1120 * should be NULL. */ 1121 1122 /** 1123 * audit_log_start - obtain an audit buffer 1124 * @ctx: audit_context (may be NULL) 1125 * @gfp_mask: type of allocation 1126 * @type: audit message type 1127 * 1128 * Returns audit_buffer pointer on success or NULL on error. 1129 * 1130 * Obtain an audit buffer. This routine does locking to obtain the 1131 * audit buffer, but then no locking is required for calls to 1132 * audit_log_*format. If the task (ctx) is a task that is currently in a 1133 * syscall, then the syscall is marked as auditable and an audit record 1134 * will be written at syscall exit. If there is no associated task, then 1135 * task context (ctx) should be NULL. 1136 */ 1137 struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask, 1138 int type) 1139 { 1140 struct audit_buffer *ab = NULL; 1141 struct timespec t; 1142 unsigned int uninitialized_var(serial); 1143 int reserve; 1144 unsigned long timeout_start = jiffies; 1145 1146 if (audit_initialized != AUDIT_INITIALIZED) 1147 return NULL; 1148 1149 if (unlikely(audit_filter_type(type))) 1150 return NULL; 1151 1152 if (gfp_mask & __GFP_WAIT) 1153 reserve = 0; 1154 else 1155 reserve = 5; /* Allow atomic callers to go up to five 1156 entries over the normal backlog limit */ 1157 1158 while (audit_backlog_limit 1159 && skb_queue_len(&audit_skb_queue) > audit_backlog_limit + reserve) { 1160 if (gfp_mask & __GFP_WAIT && audit_backlog_wait_time 1161 && time_before(jiffies, timeout_start + audit_backlog_wait_time)) { 1162 1163 /* Wait for auditd to drain the queue a little */ 1164 DECLARE_WAITQUEUE(wait, current); 1165 set_current_state(TASK_INTERRUPTIBLE); 1166 add_wait_queue(&audit_backlog_wait, &wait); 1167 1168 if (audit_backlog_limit && 1169 skb_queue_len(&audit_skb_queue) > audit_backlog_limit) 1170 schedule_timeout(timeout_start + audit_backlog_wait_time - jiffies); 1171 1172 __set_current_state(TASK_RUNNING); 1173 remove_wait_queue(&audit_backlog_wait, &wait); 1174 continue; 1175 } 1176 if (audit_rate_check() && printk_ratelimit()) 1177 printk(KERN_WARNING 1178 "audit: audit_backlog=%d > " 1179 "audit_backlog_limit=%d\n", 1180 skb_queue_len(&audit_skb_queue), 1181 audit_backlog_limit); 1182 audit_log_lost("backlog limit exceeded"); 1183 audit_backlog_wait_time = audit_backlog_wait_overflow; 1184 wake_up(&audit_backlog_wait); 1185 return NULL; 1186 } 1187 1188 ab = audit_buffer_alloc(ctx, gfp_mask, type); 1189 if (!ab) { 1190 audit_log_lost("out of memory in audit_log_start"); 1191 return NULL; 1192 } 1193 1194 audit_get_stamp(ab->ctx, &t, &serial); 1195 1196 audit_log_format(ab, "audit(%lu.%03lu:%u): ", 1197 t.tv_sec, t.tv_nsec/1000000, serial); 1198 return ab; 1199 } 1200 1201 /** 1202 * audit_expand - expand skb in the audit buffer 1203 * @ab: audit_buffer 1204 * @extra: space to add at tail of the skb 1205 * 1206 * Returns 0 (no space) on failed expansion, or available space if 1207 * successful. 1208 */ 1209 static inline int audit_expand(struct audit_buffer *ab, int extra) 1210 { 1211 struct sk_buff *skb = ab->skb; 1212 int oldtail = skb_tailroom(skb); 1213 int ret = pskb_expand_head(skb, 0, extra, ab->gfp_mask); 1214 int newtail = skb_tailroom(skb); 1215 1216 if (ret < 0) { 1217 audit_log_lost("out of memory in audit_expand"); 1218 return 0; 1219 } 1220 1221 skb->truesize += newtail - oldtail; 1222 return newtail; 1223 } 1224 1225 /* 1226 * Format an audit message into the audit buffer. If there isn't enough 1227 * room in the audit buffer, more room will be allocated and vsnprint 1228 * will be called a second time. Currently, we assume that a printk 1229 * can't format message larger than 1024 bytes, so we don't either. 1230 */ 1231 static void audit_log_vformat(struct audit_buffer *ab, const char *fmt, 1232 va_list args) 1233 { 1234 int len, avail; 1235 struct sk_buff *skb; 1236 va_list args2; 1237 1238 if (!ab) 1239 return; 1240 1241 BUG_ON(!ab->skb); 1242 skb = ab->skb; 1243 avail = skb_tailroom(skb); 1244 if (avail == 0) { 1245 avail = audit_expand(ab, AUDIT_BUFSIZ); 1246 if (!avail) 1247 goto out; 1248 } 1249 va_copy(args2, args); 1250 len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args); 1251 if (len >= avail) { 1252 /* The printk buffer is 1024 bytes long, so if we get 1253 * here and AUDIT_BUFSIZ is at least 1024, then we can 1254 * log everything that printk could have logged. */ 1255 avail = audit_expand(ab, 1256 max_t(unsigned, AUDIT_BUFSIZ, 1+len-avail)); 1257 if (!avail) 1258 goto out; 1259 len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args2); 1260 } 1261 va_end(args2); 1262 if (len > 0) 1263 skb_put(skb, len); 1264 out: 1265 return; 1266 } 1267 1268 /** 1269 * audit_log_format - format a message into the audit buffer. 1270 * @ab: audit_buffer 1271 * @fmt: format string 1272 * @...: optional parameters matching @fmt string 1273 * 1274 * All the work is done in audit_log_vformat. 1275 */ 1276 void audit_log_format(struct audit_buffer *ab, const char *fmt, ...) 1277 { 1278 va_list args; 1279 1280 if (!ab) 1281 return; 1282 va_start(args, fmt); 1283 audit_log_vformat(ab, fmt, args); 1284 va_end(args); 1285 } 1286 1287 /** 1288 * audit_log_hex - convert a buffer to hex and append it to the audit skb 1289 * @ab: the audit_buffer 1290 * @buf: buffer to convert to hex 1291 * @len: length of @buf to be converted 1292 * 1293 * No return value; failure to expand is silently ignored. 1294 * 1295 * This function will take the passed buf and convert it into a string of 1296 * ascii hex digits. The new string is placed onto the skb. 1297 */ 1298 void audit_log_n_hex(struct audit_buffer *ab, const unsigned char *buf, 1299 size_t len) 1300 { 1301 int i, avail, new_len; 1302 unsigned char *ptr; 1303 struct sk_buff *skb; 1304 static const unsigned char *hex = "0123456789ABCDEF"; 1305 1306 if (!ab) 1307 return; 1308 1309 BUG_ON(!ab->skb); 1310 skb = ab->skb; 1311 avail = skb_tailroom(skb); 1312 new_len = len<<1; 1313 if (new_len >= avail) { 1314 /* Round the buffer request up to the next multiple */ 1315 new_len = AUDIT_BUFSIZ*(((new_len-avail)/AUDIT_BUFSIZ) + 1); 1316 avail = audit_expand(ab, new_len); 1317 if (!avail) 1318 return; 1319 } 1320 1321 ptr = skb_tail_pointer(skb); 1322 for (i=0; i<len; i++) { 1323 *ptr++ = hex[(buf[i] & 0xF0)>>4]; /* Upper nibble */ 1324 *ptr++ = hex[buf[i] & 0x0F]; /* Lower nibble */ 1325 } 1326 *ptr = 0; 1327 skb_put(skb, len << 1); /* new string is twice the old string */ 1328 } 1329 1330 /* 1331 * Format a string of no more than slen characters into the audit buffer, 1332 * enclosed in quote marks. 1333 */ 1334 void audit_log_n_string(struct audit_buffer *ab, const char *string, 1335 size_t slen) 1336 { 1337 int avail, new_len; 1338 unsigned char *ptr; 1339 struct sk_buff *skb; 1340 1341 if (!ab) 1342 return; 1343 1344 BUG_ON(!ab->skb); 1345 skb = ab->skb; 1346 avail = skb_tailroom(skb); 1347 new_len = slen + 3; /* enclosing quotes + null terminator */ 1348 if (new_len > avail) { 1349 avail = audit_expand(ab, new_len); 1350 if (!avail) 1351 return; 1352 } 1353 ptr = skb_tail_pointer(skb); 1354 *ptr++ = '"'; 1355 memcpy(ptr, string, slen); 1356 ptr += slen; 1357 *ptr++ = '"'; 1358 *ptr = 0; 1359 skb_put(skb, slen + 2); /* don't include null terminator */ 1360 } 1361 1362 /** 1363 * audit_string_contains_control - does a string need to be logged in hex 1364 * @string: string to be checked 1365 * @len: max length of the string to check 1366 */ 1367 int audit_string_contains_control(const char *string, size_t len) 1368 { 1369 const unsigned char *p; 1370 for (p = string; p < (const unsigned char *)string + len; p++) { 1371 if (*p == '"' || *p < 0x21 || *p > 0x7e) 1372 return 1; 1373 } 1374 return 0; 1375 } 1376 1377 /** 1378 * audit_log_n_untrustedstring - log a string that may contain random characters 1379 * @ab: audit_buffer 1380 * @len: length of string (not including trailing null) 1381 * @string: string to be logged 1382 * 1383 * This code will escape a string that is passed to it if the string 1384 * contains a control character, unprintable character, double quote mark, 1385 * or a space. Unescaped strings will start and end with a double quote mark. 1386 * Strings that are escaped are printed in hex (2 digits per char). 1387 * 1388 * The caller specifies the number of characters in the string to log, which may 1389 * or may not be the entire string. 1390 */ 1391 void audit_log_n_untrustedstring(struct audit_buffer *ab, const char *string, 1392 size_t len) 1393 { 1394 if (audit_string_contains_control(string, len)) 1395 audit_log_n_hex(ab, string, len); 1396 else 1397 audit_log_n_string(ab, string, len); 1398 } 1399 1400 /** 1401 * audit_log_untrustedstring - log a string that may contain random characters 1402 * @ab: audit_buffer 1403 * @string: string to be logged 1404 * 1405 * Same as audit_log_n_untrustedstring(), except that strlen is used to 1406 * determine string length. 1407 */ 1408 void audit_log_untrustedstring(struct audit_buffer *ab, const char *string) 1409 { 1410 audit_log_n_untrustedstring(ab, string, strlen(string)); 1411 } 1412 1413 /* This is a helper-function to print the escaped d_path */ 1414 void audit_log_d_path(struct audit_buffer *ab, const char *prefix, 1415 struct path *path) 1416 { 1417 char *p, *pathname; 1418 1419 if (prefix) 1420 audit_log_format(ab, " %s", prefix); 1421 1422 /* We will allow 11 spaces for ' (deleted)' to be appended */ 1423 pathname = kmalloc(PATH_MAX+11, ab->gfp_mask); 1424 if (!pathname) { 1425 audit_log_string(ab, "<no_memory>"); 1426 return; 1427 } 1428 p = d_path(path, pathname, PATH_MAX+11); 1429 if (IS_ERR(p)) { /* Should never happen since we send PATH_MAX */ 1430 /* FIXME: can we save some information here? */ 1431 audit_log_string(ab, "<too_long>"); 1432 } else 1433 audit_log_untrustedstring(ab, p); 1434 kfree(pathname); 1435 } 1436 1437 void audit_log_key(struct audit_buffer *ab, char *key) 1438 { 1439 audit_log_format(ab, " key="); 1440 if (key) 1441 audit_log_untrustedstring(ab, key); 1442 else 1443 audit_log_format(ab, "(null)"); 1444 } 1445 1446 /** 1447 * audit_log_end - end one audit record 1448 * @ab: the audit_buffer 1449 * 1450 * The netlink_* functions cannot be called inside an irq context, so 1451 * the audit buffer is placed on a queue and a tasklet is scheduled to 1452 * remove them from the queue outside the irq context. May be called in 1453 * any context. 1454 */ 1455 void audit_log_end(struct audit_buffer *ab) 1456 { 1457 if (!ab) 1458 return; 1459 if (!audit_rate_check()) { 1460 audit_log_lost("rate limit exceeded"); 1461 } else { 1462 struct nlmsghdr *nlh = nlmsg_hdr(ab->skb); 1463 nlh->nlmsg_len = ab->skb->len - NLMSG_SPACE(0); 1464 1465 if (audit_pid) { 1466 skb_queue_tail(&audit_skb_queue, ab->skb); 1467 wake_up_interruptible(&kauditd_wait); 1468 } else { 1469 audit_printk_skb(ab->skb); 1470 } 1471 ab->skb = NULL; 1472 } 1473 audit_buffer_free(ab); 1474 } 1475 1476 /** 1477 * audit_log - Log an audit record 1478 * @ctx: audit context 1479 * @gfp_mask: type of allocation 1480 * @type: audit message type 1481 * @fmt: format string to use 1482 * @...: variable parameters matching the format string 1483 * 1484 * This is a convenience function that calls audit_log_start, 1485 * audit_log_vformat, and audit_log_end. It may be called 1486 * in any context. 1487 */ 1488 void audit_log(struct audit_context *ctx, gfp_t gfp_mask, int type, 1489 const char *fmt, ...) 1490 { 1491 struct audit_buffer *ab; 1492 va_list args; 1493 1494 ab = audit_log_start(ctx, gfp_mask, type); 1495 if (ab) { 1496 va_start(args, fmt); 1497 audit_log_vformat(ab, fmt, args); 1498 va_end(args); 1499 audit_log_end(ab); 1500 } 1501 } 1502 1503 EXPORT_SYMBOL(audit_log_start); 1504 EXPORT_SYMBOL(audit_log_end); 1505 EXPORT_SYMBOL(audit_log_format); 1506 EXPORT_SYMBOL(audit_log); 1507