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 <linux/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 #ifdef CONFIG_SECURITY 59 #include <linux/security.h> 60 #endif 61 #include <linux/netlink.h> 62 #include <linux/freezer.h> 63 #include <linux/tty.h> 64 65 #include "audit.h" 66 67 /* No auditing will take place until audit_initialized == AUDIT_INITIALIZED. 68 * (Initialization happens after skb_init is called.) */ 69 #define AUDIT_DISABLED -1 70 #define AUDIT_UNINITIALIZED 0 71 #define AUDIT_INITIALIZED 1 72 static int audit_initialized; 73 74 #define AUDIT_OFF 0 75 #define AUDIT_ON 1 76 #define AUDIT_LOCKED 2 77 int audit_enabled; 78 int audit_ever_enabled; 79 80 EXPORT_SYMBOL_GPL(audit_enabled); 81 82 /* Default state when kernel boots without any parameters. */ 83 static int audit_default; 84 85 /* If auditing cannot proceed, audit_failure selects what happens. */ 86 static int audit_failure = AUDIT_FAIL_PRINTK; 87 88 /* 89 * If audit records are to be written to the netlink socket, audit_pid 90 * contains the pid of the auditd process and audit_nlk_pid contains 91 * the pid to use to send netlink messages to that process. 92 */ 93 int audit_pid; 94 static int audit_nlk_pid; 95 96 /* If audit_rate_limit is non-zero, limit the rate of sending audit records 97 * to that number per second. This prevents DoS attacks, but results in 98 * audit records being dropped. */ 99 static int audit_rate_limit; 100 101 /* Number of outstanding audit_buffers allowed. */ 102 static int audit_backlog_limit = 64; 103 static int audit_backlog_wait_time = 60 * HZ; 104 static int audit_backlog_wait_overflow = 0; 105 106 /* The identity of the user shutting down the audit system. */ 107 uid_t audit_sig_uid = -1; 108 pid_t audit_sig_pid = -1; 109 u32 audit_sig_sid = 0; 110 111 /* Records can be lost in several ways: 112 0) [suppressed in audit_alloc] 113 1) out of memory in audit_log_start [kmalloc of struct audit_buffer] 114 2) out of memory in audit_log_move [alloc_skb] 115 3) suppressed due to audit_rate_limit 116 4) suppressed due to audit_backlog_limit 117 */ 118 static atomic_t audit_lost = ATOMIC_INIT(0); 119 120 /* The netlink socket. */ 121 static struct sock *audit_sock; 122 123 /* Hash for inode-based rules */ 124 struct list_head audit_inode_hash[AUDIT_INODE_BUCKETS]; 125 126 /* The audit_freelist is a list of pre-allocated audit buffers (if more 127 * than AUDIT_MAXFREE are in use, the audit buffer is freed instead of 128 * being placed on the freelist). */ 129 static DEFINE_SPINLOCK(audit_freelist_lock); 130 static int audit_freelist_count; 131 static LIST_HEAD(audit_freelist); 132 133 static struct sk_buff_head audit_skb_queue; 134 /* queue of skbs to send to auditd when/if it comes back */ 135 static struct sk_buff_head audit_skb_hold_queue; 136 static struct task_struct *kauditd_task; 137 static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait); 138 static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait); 139 140 /* Serialize requests from userspace. */ 141 DEFINE_MUTEX(audit_cmd_mutex); 142 143 /* AUDIT_BUFSIZ is the size of the temporary buffer used for formatting 144 * audit records. Since printk uses a 1024 byte buffer, this buffer 145 * should be at least that large. */ 146 #define AUDIT_BUFSIZ 1024 147 148 /* AUDIT_MAXFREE is the number of empty audit_buffers we keep on the 149 * audit_freelist. Doing so eliminates many kmalloc/kfree calls. */ 150 #define AUDIT_MAXFREE (2*NR_CPUS) 151 152 /* The audit_buffer is used when formatting an audit record. The caller 153 * locks briefly to get the record off the freelist or to allocate the 154 * buffer, and locks briefly to send the buffer to the netlink layer or 155 * to place it on a transmit queue. Multiple audit_buffers can be in 156 * use simultaneously. */ 157 struct audit_buffer { 158 struct list_head list; 159 struct sk_buff *skb; /* formatted skb ready to send */ 160 struct audit_context *ctx; /* NULL or associated context */ 161 gfp_t gfp_mask; 162 }; 163 164 struct audit_reply { 165 int pid; 166 struct sk_buff *skb; 167 }; 168 169 static void audit_set_pid(struct audit_buffer *ab, pid_t pid) 170 { 171 if (ab) { 172 struct nlmsghdr *nlh = nlmsg_hdr(ab->skb); 173 nlh->nlmsg_pid = pid; 174 } 175 } 176 177 void audit_panic(const char *message) 178 { 179 switch (audit_failure) 180 { 181 case AUDIT_FAIL_SILENT: 182 break; 183 case AUDIT_FAIL_PRINTK: 184 if (printk_ratelimit()) 185 printk(KERN_ERR "audit: %s\n", message); 186 break; 187 case AUDIT_FAIL_PANIC: 188 /* test audit_pid since printk is always losey, why bother? */ 189 if (audit_pid) 190 panic("audit: %s\n", message); 191 break; 192 } 193 } 194 195 static inline int audit_rate_check(void) 196 { 197 static unsigned long last_check = 0; 198 static int messages = 0; 199 static DEFINE_SPINLOCK(lock); 200 unsigned long flags; 201 unsigned long now; 202 unsigned long elapsed; 203 int retval = 0; 204 205 if (!audit_rate_limit) return 1; 206 207 spin_lock_irqsave(&lock, flags); 208 if (++messages < audit_rate_limit) { 209 retval = 1; 210 } else { 211 now = jiffies; 212 elapsed = now - last_check; 213 if (elapsed > HZ) { 214 last_check = now; 215 messages = 0; 216 retval = 1; 217 } 218 } 219 spin_unlock_irqrestore(&lock, flags); 220 221 return retval; 222 } 223 224 /** 225 * audit_log_lost - conditionally log lost audit message event 226 * @message: the message stating reason for lost audit message 227 * 228 * Emit at least 1 message per second, even if audit_rate_check is 229 * throttling. 230 * Always increment the lost messages counter. 231 */ 232 void audit_log_lost(const char *message) 233 { 234 static unsigned long last_msg = 0; 235 static DEFINE_SPINLOCK(lock); 236 unsigned long flags; 237 unsigned long now; 238 int print; 239 240 atomic_inc(&audit_lost); 241 242 print = (audit_failure == AUDIT_FAIL_PANIC || !audit_rate_limit); 243 244 if (!print) { 245 spin_lock_irqsave(&lock, flags); 246 now = jiffies; 247 if (now - last_msg > HZ) { 248 print = 1; 249 last_msg = now; 250 } 251 spin_unlock_irqrestore(&lock, flags); 252 } 253 254 if (print) { 255 if (printk_ratelimit()) 256 printk(KERN_WARNING 257 "audit: audit_lost=%d audit_rate_limit=%d " 258 "audit_backlog_limit=%d\n", 259 atomic_read(&audit_lost), 260 audit_rate_limit, 261 audit_backlog_limit); 262 audit_panic(message); 263 } 264 } 265 266 static int audit_log_config_change(char *function_name, int new, int old, 267 uid_t loginuid, u32 sessionid, u32 sid, 268 int allow_changes) 269 { 270 struct audit_buffer *ab; 271 int rc = 0; 272 273 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE); 274 audit_log_format(ab, "%s=%d old=%d auid=%u ses=%u", function_name, new, 275 old, loginuid, sessionid); 276 if (sid) { 277 char *ctx = NULL; 278 u32 len; 279 280 rc = security_secid_to_secctx(sid, &ctx, &len); 281 if (rc) { 282 audit_log_format(ab, " sid=%u", sid); 283 allow_changes = 0; /* Something weird, deny request */ 284 } else { 285 audit_log_format(ab, " subj=%s", ctx); 286 security_release_secctx(ctx, len); 287 } 288 } 289 audit_log_format(ab, " res=%d", allow_changes); 290 audit_log_end(ab); 291 return rc; 292 } 293 294 static int audit_do_config_change(char *function_name, int *to_change, 295 int new, uid_t loginuid, u32 sessionid, 296 u32 sid) 297 { 298 int allow_changes, rc = 0, old = *to_change; 299 300 /* check if we are locked */ 301 if (audit_enabled == AUDIT_LOCKED) 302 allow_changes = 0; 303 else 304 allow_changes = 1; 305 306 if (audit_enabled != AUDIT_OFF) { 307 rc = audit_log_config_change(function_name, new, old, loginuid, 308 sessionid, sid, allow_changes); 309 if (rc) 310 allow_changes = 0; 311 } 312 313 /* If we are allowed, make the change */ 314 if (allow_changes == 1) 315 *to_change = new; 316 /* Not allowed, update reason */ 317 else if (rc == 0) 318 rc = -EPERM; 319 return rc; 320 } 321 322 static int audit_set_rate_limit(int limit, uid_t loginuid, u32 sessionid, 323 u32 sid) 324 { 325 return audit_do_config_change("audit_rate_limit", &audit_rate_limit, 326 limit, loginuid, sessionid, sid); 327 } 328 329 static int audit_set_backlog_limit(int limit, uid_t loginuid, u32 sessionid, 330 u32 sid) 331 { 332 return audit_do_config_change("audit_backlog_limit", &audit_backlog_limit, 333 limit, loginuid, sessionid, sid); 334 } 335 336 static int audit_set_enabled(int state, uid_t loginuid, u32 sessionid, u32 sid) 337 { 338 int rc; 339 if (state < AUDIT_OFF || state > AUDIT_LOCKED) 340 return -EINVAL; 341 342 rc = audit_do_config_change("audit_enabled", &audit_enabled, state, 343 loginuid, sessionid, sid); 344 345 if (!rc) 346 audit_ever_enabled |= !!state; 347 348 return rc; 349 } 350 351 static int audit_set_failure(int state, uid_t loginuid, u32 sessionid, u32 sid) 352 { 353 if (state != AUDIT_FAIL_SILENT 354 && state != AUDIT_FAIL_PRINTK 355 && state != AUDIT_FAIL_PANIC) 356 return -EINVAL; 357 358 return audit_do_config_change("audit_failure", &audit_failure, state, 359 loginuid, sessionid, sid); 360 } 361 362 /* 363 * Queue skbs to be sent to auditd when/if it comes back. These skbs should 364 * already have been sent via prink/syslog and so if these messages are dropped 365 * it is not a huge concern since we already passed the audit_log_lost() 366 * notification and stuff. This is just nice to get audit messages during 367 * boot before auditd is running or messages generated while auditd is stopped. 368 * This only holds messages is audit_default is set, aka booting with audit=1 369 * or building your kernel that way. 370 */ 371 static void audit_hold_skb(struct sk_buff *skb) 372 { 373 if (audit_default && 374 skb_queue_len(&audit_skb_hold_queue) < audit_backlog_limit) 375 skb_queue_tail(&audit_skb_hold_queue, skb); 376 else 377 kfree_skb(skb); 378 } 379 380 /* 381 * For one reason or another this nlh isn't getting delivered to the userspace 382 * audit daemon, just send it to printk. 383 */ 384 static void audit_printk_skb(struct sk_buff *skb) 385 { 386 struct nlmsghdr *nlh = nlmsg_hdr(skb); 387 char *data = NLMSG_DATA(nlh); 388 389 if (nlh->nlmsg_type != AUDIT_EOE) { 390 if (printk_ratelimit()) 391 printk(KERN_NOTICE "type=%d %s\n", nlh->nlmsg_type, data); 392 else 393 audit_log_lost("printk limit exceeded\n"); 394 } 395 396 audit_hold_skb(skb); 397 } 398 399 static void kauditd_send_skb(struct sk_buff *skb) 400 { 401 int err; 402 /* take a reference in case we can't send it and we want to hold it */ 403 skb_get(skb); 404 err = netlink_unicast(audit_sock, skb, audit_nlk_pid, 0); 405 if (err < 0) { 406 BUG_ON(err != -ECONNREFUSED); /* Shouldn't happen */ 407 printk(KERN_ERR "audit: *NO* daemon at audit_pid=%d\n", audit_pid); 408 audit_log_lost("auditd disappeared\n"); 409 audit_pid = 0; 410 /* we might get lucky and get this in the next auditd */ 411 audit_hold_skb(skb); 412 } else 413 /* drop the extra reference if sent ok */ 414 consume_skb(skb); 415 } 416 417 static int kauditd_thread(void *dummy) 418 { 419 struct sk_buff *skb; 420 421 set_freezable(); 422 while (!kthread_should_stop()) { 423 /* 424 * if auditd just started drain the queue of messages already 425 * sent to syslog/printk. remember loss here is ok. we already 426 * called audit_log_lost() if it didn't go out normally. so the 427 * race between the skb_dequeue and the next check for audit_pid 428 * doesn't matter. 429 * 430 * if you ever find kauditd to be too slow we can get a perf win 431 * by doing our own locking and keeping better track if there 432 * are messages in this queue. I don't see the need now, but 433 * in 5 years when I want to play with this again I'll see this 434 * note and still have no friggin idea what i'm thinking today. 435 */ 436 if (audit_default && audit_pid) { 437 skb = skb_dequeue(&audit_skb_hold_queue); 438 if (unlikely(skb)) { 439 while (skb && audit_pid) { 440 kauditd_send_skb(skb); 441 skb = skb_dequeue(&audit_skb_hold_queue); 442 } 443 } 444 } 445 446 skb = skb_dequeue(&audit_skb_queue); 447 wake_up(&audit_backlog_wait); 448 if (skb) { 449 if (audit_pid) 450 kauditd_send_skb(skb); 451 else 452 audit_printk_skb(skb); 453 } else { 454 DECLARE_WAITQUEUE(wait, current); 455 set_current_state(TASK_INTERRUPTIBLE); 456 add_wait_queue(&kauditd_wait, &wait); 457 458 if (!skb_queue_len(&audit_skb_queue)) { 459 try_to_freeze(); 460 schedule(); 461 } 462 463 __set_current_state(TASK_RUNNING); 464 remove_wait_queue(&kauditd_wait, &wait); 465 } 466 } 467 return 0; 468 } 469 470 static int audit_prepare_user_tty(pid_t pid, uid_t loginuid, u32 sessionid) 471 { 472 struct task_struct *tsk; 473 int err; 474 475 rcu_read_lock(); 476 tsk = find_task_by_vpid(pid); 477 if (!tsk) { 478 rcu_read_unlock(); 479 return -ESRCH; 480 } 481 get_task_struct(tsk); 482 rcu_read_unlock(); 483 err = tty_audit_push_task(tsk, loginuid, sessionid); 484 put_task_struct(tsk); 485 return err; 486 } 487 488 int audit_send_list(void *_dest) 489 { 490 struct audit_netlink_list *dest = _dest; 491 int pid = dest->pid; 492 struct sk_buff *skb; 493 494 /* wait for parent to finish and send an ACK */ 495 mutex_lock(&audit_cmd_mutex); 496 mutex_unlock(&audit_cmd_mutex); 497 498 while ((skb = __skb_dequeue(&dest->q)) != NULL) 499 netlink_unicast(audit_sock, skb, pid, 0); 500 501 kfree(dest); 502 503 return 0; 504 } 505 506 struct sk_buff *audit_make_reply(int pid, int seq, int type, int done, 507 int multi, const void *payload, int size) 508 { 509 struct sk_buff *skb; 510 struct nlmsghdr *nlh; 511 void *data; 512 int flags = multi ? NLM_F_MULTI : 0; 513 int t = done ? NLMSG_DONE : type; 514 515 skb = nlmsg_new(size, GFP_KERNEL); 516 if (!skb) 517 return NULL; 518 519 nlh = NLMSG_NEW(skb, pid, seq, t, size, flags); 520 data = NLMSG_DATA(nlh); 521 memcpy(data, payload, size); 522 return skb; 523 524 nlmsg_failure: /* Used by NLMSG_NEW */ 525 if (skb) 526 kfree_skb(skb); 527 return NULL; 528 } 529 530 static int audit_send_reply_thread(void *arg) 531 { 532 struct audit_reply *reply = (struct audit_reply *)arg; 533 534 mutex_lock(&audit_cmd_mutex); 535 mutex_unlock(&audit_cmd_mutex); 536 537 /* Ignore failure. It'll only happen if the sender goes away, 538 because our timeout is set to infinite. */ 539 netlink_unicast(audit_sock, reply->skb, reply->pid, 0); 540 kfree(reply); 541 return 0; 542 } 543 /** 544 * audit_send_reply - send an audit reply message via netlink 545 * @pid: process id to send reply to 546 * @seq: sequence number 547 * @type: audit message type 548 * @done: done (last) flag 549 * @multi: multi-part message flag 550 * @payload: payload data 551 * @size: payload size 552 * 553 * Allocates an skb, builds the netlink message, and sends it to the pid. 554 * No failure notifications. 555 */ 556 static void audit_send_reply(int pid, int seq, int type, int done, int multi, 557 const void *payload, int size) 558 { 559 struct sk_buff *skb; 560 struct task_struct *tsk; 561 struct audit_reply *reply = kmalloc(sizeof(struct audit_reply), 562 GFP_KERNEL); 563 564 if (!reply) 565 return; 566 567 skb = audit_make_reply(pid, seq, type, done, multi, payload, size); 568 if (!skb) 569 goto out; 570 571 reply->pid = pid; 572 reply->skb = skb; 573 574 tsk = kthread_run(audit_send_reply_thread, reply, "audit_send_reply"); 575 if (!IS_ERR(tsk)) 576 return; 577 kfree_skb(skb); 578 out: 579 kfree(reply); 580 } 581 582 /* 583 * Check for appropriate CAP_AUDIT_ capabilities on incoming audit 584 * control messages. 585 */ 586 static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type) 587 { 588 int err = 0; 589 590 switch (msg_type) { 591 case AUDIT_GET: 592 case AUDIT_LIST: 593 case AUDIT_LIST_RULES: 594 case AUDIT_SET: 595 case AUDIT_ADD: 596 case AUDIT_ADD_RULE: 597 case AUDIT_DEL: 598 case AUDIT_DEL_RULE: 599 case AUDIT_SIGNAL_INFO: 600 case AUDIT_TTY_GET: 601 case AUDIT_TTY_SET: 602 case AUDIT_TRIM: 603 case AUDIT_MAKE_EQUIV: 604 if (security_netlink_recv(skb, CAP_AUDIT_CONTROL)) 605 err = -EPERM; 606 break; 607 case AUDIT_USER: 608 case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG: 609 case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2: 610 if (security_netlink_recv(skb, CAP_AUDIT_WRITE)) 611 err = -EPERM; 612 break; 613 default: /* bad msg */ 614 err = -EINVAL; 615 } 616 617 return err; 618 } 619 620 static int audit_log_common_recv_msg(struct audit_buffer **ab, u16 msg_type, 621 u32 pid, u32 uid, uid_t auid, u32 ses, 622 u32 sid) 623 { 624 int rc = 0; 625 char *ctx = NULL; 626 u32 len; 627 628 if (!audit_enabled) { 629 *ab = NULL; 630 return rc; 631 } 632 633 *ab = audit_log_start(NULL, GFP_KERNEL, msg_type); 634 audit_log_format(*ab, "user pid=%d uid=%u auid=%u ses=%u", 635 pid, uid, auid, ses); 636 if (sid) { 637 rc = security_secid_to_secctx(sid, &ctx, &len); 638 if (rc) 639 audit_log_format(*ab, " ssid=%u", sid); 640 else { 641 audit_log_format(*ab, " subj=%s", ctx); 642 security_release_secctx(ctx, len); 643 } 644 } 645 646 return rc; 647 } 648 649 static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) 650 { 651 u32 uid, pid, seq, sid; 652 void *data; 653 struct audit_status *status_get, status_set; 654 int err; 655 struct audit_buffer *ab; 656 u16 msg_type = nlh->nlmsg_type; 657 uid_t loginuid; /* loginuid of sender */ 658 u32 sessionid; 659 struct audit_sig_info *sig_data; 660 char *ctx = NULL; 661 u32 len; 662 663 err = audit_netlink_ok(skb, msg_type); 664 if (err) 665 return err; 666 667 /* As soon as there's any sign of userspace auditd, 668 * start kauditd to talk to it */ 669 if (!kauditd_task) 670 kauditd_task = kthread_run(kauditd_thread, NULL, "kauditd"); 671 if (IS_ERR(kauditd_task)) { 672 err = PTR_ERR(kauditd_task); 673 kauditd_task = NULL; 674 return err; 675 } 676 677 pid = NETLINK_CREDS(skb)->pid; 678 uid = NETLINK_CREDS(skb)->uid; 679 loginuid = audit_get_loginuid(current); 680 sessionid = audit_get_sessionid(current); 681 security_task_getsecid(current, &sid); 682 seq = nlh->nlmsg_seq; 683 data = NLMSG_DATA(nlh); 684 685 switch (msg_type) { 686 case AUDIT_GET: 687 status_set.enabled = audit_enabled; 688 status_set.failure = audit_failure; 689 status_set.pid = audit_pid; 690 status_set.rate_limit = audit_rate_limit; 691 status_set.backlog_limit = audit_backlog_limit; 692 status_set.lost = atomic_read(&audit_lost); 693 status_set.backlog = skb_queue_len(&audit_skb_queue); 694 audit_send_reply(NETLINK_CB(skb).pid, seq, AUDIT_GET, 0, 0, 695 &status_set, sizeof(status_set)); 696 break; 697 case AUDIT_SET: 698 if (nlh->nlmsg_len < sizeof(struct audit_status)) 699 return -EINVAL; 700 status_get = (struct audit_status *)data; 701 if (status_get->mask & AUDIT_STATUS_ENABLED) { 702 err = audit_set_enabled(status_get->enabled, 703 loginuid, sessionid, sid); 704 if (err < 0) 705 return err; 706 } 707 if (status_get->mask & AUDIT_STATUS_FAILURE) { 708 err = audit_set_failure(status_get->failure, 709 loginuid, sessionid, sid); 710 if (err < 0) 711 return err; 712 } 713 if (status_get->mask & AUDIT_STATUS_PID) { 714 int new_pid = status_get->pid; 715 716 if (audit_enabled != AUDIT_OFF) 717 audit_log_config_change("audit_pid", new_pid, 718 audit_pid, loginuid, 719 sessionid, sid, 1); 720 721 audit_pid = new_pid; 722 audit_nlk_pid = NETLINK_CB(skb).pid; 723 } 724 if (status_get->mask & AUDIT_STATUS_RATE_LIMIT) { 725 err = audit_set_rate_limit(status_get->rate_limit, 726 loginuid, sessionid, sid); 727 if (err < 0) 728 return err; 729 } 730 if (status_get->mask & AUDIT_STATUS_BACKLOG_LIMIT) 731 err = audit_set_backlog_limit(status_get->backlog_limit, 732 loginuid, sessionid, sid); 733 break; 734 case AUDIT_USER: 735 case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG: 736 case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2: 737 if (!audit_enabled && msg_type != AUDIT_USER_AVC) 738 return 0; 739 740 err = audit_filter_user(&NETLINK_CB(skb)); 741 if (err == 1) { 742 err = 0; 743 if (msg_type == AUDIT_USER_TTY) { 744 err = audit_prepare_user_tty(pid, loginuid, 745 sessionid); 746 if (err) 747 break; 748 } 749 audit_log_common_recv_msg(&ab, msg_type, pid, uid, 750 loginuid, sessionid, sid); 751 752 if (msg_type != AUDIT_USER_TTY) 753 audit_log_format(ab, " msg='%.1024s'", 754 (char *)data); 755 else { 756 int size; 757 758 audit_log_format(ab, " msg="); 759 size = nlmsg_len(nlh); 760 if (size > 0 && 761 ((unsigned char *)data)[size - 1] == '\0') 762 size--; 763 audit_log_n_untrustedstring(ab, data, size); 764 } 765 audit_set_pid(ab, pid); 766 audit_log_end(ab); 767 } 768 break; 769 case AUDIT_ADD: 770 case AUDIT_DEL: 771 if (nlmsg_len(nlh) < sizeof(struct audit_rule)) 772 return -EINVAL; 773 if (audit_enabled == AUDIT_LOCKED) { 774 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE, pid, 775 uid, loginuid, sessionid, sid); 776 777 audit_log_format(ab, " audit_enabled=%d res=0", 778 audit_enabled); 779 audit_log_end(ab); 780 return -EPERM; 781 } 782 /* fallthrough */ 783 case AUDIT_LIST: 784 err = audit_receive_filter(msg_type, NETLINK_CB(skb).pid, 785 uid, seq, data, nlmsg_len(nlh), 786 loginuid, sessionid, sid); 787 break; 788 case AUDIT_ADD_RULE: 789 case AUDIT_DEL_RULE: 790 if (nlmsg_len(nlh) < sizeof(struct audit_rule_data)) 791 return -EINVAL; 792 if (audit_enabled == AUDIT_LOCKED) { 793 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE, pid, 794 uid, loginuid, sessionid, sid); 795 796 audit_log_format(ab, " audit_enabled=%d res=0", 797 audit_enabled); 798 audit_log_end(ab); 799 return -EPERM; 800 } 801 /* fallthrough */ 802 case AUDIT_LIST_RULES: 803 err = audit_receive_filter(msg_type, NETLINK_CB(skb).pid, 804 uid, seq, data, nlmsg_len(nlh), 805 loginuid, sessionid, sid); 806 break; 807 case AUDIT_TRIM: 808 audit_trim_trees(); 809 810 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE, pid, 811 uid, loginuid, sessionid, sid); 812 813 audit_log_format(ab, " op=trim res=1"); 814 audit_log_end(ab); 815 break; 816 case AUDIT_MAKE_EQUIV: { 817 void *bufp = data; 818 u32 sizes[2]; 819 size_t msglen = nlmsg_len(nlh); 820 char *old, *new; 821 822 err = -EINVAL; 823 if (msglen < 2 * sizeof(u32)) 824 break; 825 memcpy(sizes, bufp, 2 * sizeof(u32)); 826 bufp += 2 * sizeof(u32); 827 msglen -= 2 * sizeof(u32); 828 old = audit_unpack_string(&bufp, &msglen, sizes[0]); 829 if (IS_ERR(old)) { 830 err = PTR_ERR(old); 831 break; 832 } 833 new = audit_unpack_string(&bufp, &msglen, sizes[1]); 834 if (IS_ERR(new)) { 835 err = PTR_ERR(new); 836 kfree(old); 837 break; 838 } 839 /* OK, here comes... */ 840 err = audit_tag_tree(old, new); 841 842 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE, pid, 843 uid, loginuid, sessionid, sid); 844 845 audit_log_format(ab, " op=make_equiv old="); 846 audit_log_untrustedstring(ab, old); 847 audit_log_format(ab, " new="); 848 audit_log_untrustedstring(ab, new); 849 audit_log_format(ab, " res=%d", !err); 850 audit_log_end(ab); 851 kfree(old); 852 kfree(new); 853 break; 854 } 855 case AUDIT_SIGNAL_INFO: 856 len = 0; 857 if (audit_sig_sid) { 858 err = security_secid_to_secctx(audit_sig_sid, &ctx, &len); 859 if (err) 860 return err; 861 } 862 sig_data = kmalloc(sizeof(*sig_data) + len, GFP_KERNEL); 863 if (!sig_data) { 864 if (audit_sig_sid) 865 security_release_secctx(ctx, len); 866 return -ENOMEM; 867 } 868 sig_data->uid = audit_sig_uid; 869 sig_data->pid = audit_sig_pid; 870 if (audit_sig_sid) { 871 memcpy(sig_data->ctx, ctx, len); 872 security_release_secctx(ctx, len); 873 } 874 audit_send_reply(NETLINK_CB(skb).pid, seq, AUDIT_SIGNAL_INFO, 875 0, 0, sig_data, sizeof(*sig_data) + len); 876 kfree(sig_data); 877 break; 878 case AUDIT_TTY_GET: { 879 struct audit_tty_status s; 880 struct task_struct *tsk; 881 unsigned long flags; 882 883 rcu_read_lock(); 884 tsk = find_task_by_vpid(pid); 885 if (tsk && lock_task_sighand(tsk, &flags)) { 886 s.enabled = tsk->signal->audit_tty != 0; 887 unlock_task_sighand(tsk, &flags); 888 } else 889 err = -ESRCH; 890 rcu_read_unlock(); 891 892 if (!err) 893 audit_send_reply(NETLINK_CB(skb).pid, seq, 894 AUDIT_TTY_GET, 0, 0, &s, sizeof(s)); 895 break; 896 } 897 case AUDIT_TTY_SET: { 898 struct audit_tty_status *s; 899 struct task_struct *tsk; 900 unsigned long flags; 901 902 if (nlh->nlmsg_len < sizeof(struct audit_tty_status)) 903 return -EINVAL; 904 s = data; 905 if (s->enabled != 0 && s->enabled != 1) 906 return -EINVAL; 907 rcu_read_lock(); 908 tsk = find_task_by_vpid(pid); 909 if (tsk && lock_task_sighand(tsk, &flags)) { 910 tsk->signal->audit_tty = s->enabled != 0; 911 unlock_task_sighand(tsk, &flags); 912 } else 913 err = -ESRCH; 914 rcu_read_unlock(); 915 break; 916 } 917 default: 918 err = -EINVAL; 919 break; 920 } 921 922 return err < 0 ? err : 0; 923 } 924 925 /* 926 * Get message from skb. Each message is processed by audit_receive_msg. 927 * Malformed skbs with wrong length are discarded silently. 928 */ 929 static void audit_receive_skb(struct sk_buff *skb) 930 { 931 struct nlmsghdr *nlh; 932 /* 933 * len MUST be signed for NLMSG_NEXT to be able to dec it below 0 934 * if the nlmsg_len was not aligned 935 */ 936 int len; 937 int err; 938 939 nlh = nlmsg_hdr(skb); 940 len = skb->len; 941 942 while (NLMSG_OK(nlh, len)) { 943 err = audit_receive_msg(skb, nlh); 944 /* if err or if this message says it wants a response */ 945 if (err || (nlh->nlmsg_flags & NLM_F_ACK)) 946 netlink_ack(skb, nlh, err); 947 948 nlh = NLMSG_NEXT(nlh, len); 949 } 950 } 951 952 /* Receive messages from netlink socket. */ 953 static void audit_receive(struct sk_buff *skb) 954 { 955 mutex_lock(&audit_cmd_mutex); 956 audit_receive_skb(skb); 957 mutex_unlock(&audit_cmd_mutex); 958 } 959 960 /* Initialize audit support at boot time. */ 961 static int __init audit_init(void) 962 { 963 int i; 964 965 if (audit_initialized == AUDIT_DISABLED) 966 return 0; 967 968 printk(KERN_INFO "audit: initializing netlink socket (%s)\n", 969 audit_default ? "enabled" : "disabled"); 970 audit_sock = netlink_kernel_create(&init_net, NETLINK_AUDIT, 0, 971 audit_receive, NULL, THIS_MODULE); 972 if (!audit_sock) 973 audit_panic("cannot initialize netlink socket"); 974 else 975 audit_sock->sk_sndtimeo = MAX_SCHEDULE_TIMEOUT; 976 977 skb_queue_head_init(&audit_skb_queue); 978 skb_queue_head_init(&audit_skb_hold_queue); 979 audit_initialized = AUDIT_INITIALIZED; 980 audit_enabled = audit_default; 981 audit_ever_enabled |= !!audit_default; 982 983 audit_log(NULL, GFP_KERNEL, AUDIT_KERNEL, "initialized"); 984 985 for (i = 0; i < AUDIT_INODE_BUCKETS; i++) 986 INIT_LIST_HEAD(&audit_inode_hash[i]); 987 988 return 0; 989 } 990 __initcall(audit_init); 991 992 /* Process kernel command-line parameter at boot time. audit=0 or audit=1. */ 993 static int __init audit_enable(char *str) 994 { 995 audit_default = !!simple_strtol(str, NULL, 0); 996 if (!audit_default) 997 audit_initialized = AUDIT_DISABLED; 998 999 printk(KERN_INFO "audit: %s", audit_default ? "enabled" : "disabled"); 1000 1001 if (audit_initialized == AUDIT_INITIALIZED) { 1002 audit_enabled = audit_default; 1003 audit_ever_enabled |= !!audit_default; 1004 } else if (audit_initialized == AUDIT_UNINITIALIZED) { 1005 printk(" (after initialization)"); 1006 } else { 1007 printk(" (until reboot)"); 1008 } 1009 printk("\n"); 1010 1011 return 1; 1012 } 1013 1014 __setup("audit=", audit_enable); 1015 1016 static void audit_buffer_free(struct audit_buffer *ab) 1017 { 1018 unsigned long flags; 1019 1020 if (!ab) 1021 return; 1022 1023 if (ab->skb) 1024 kfree_skb(ab->skb); 1025 1026 spin_lock_irqsave(&audit_freelist_lock, flags); 1027 if (audit_freelist_count > AUDIT_MAXFREE) 1028 kfree(ab); 1029 else { 1030 audit_freelist_count++; 1031 list_add(&ab->list, &audit_freelist); 1032 } 1033 spin_unlock_irqrestore(&audit_freelist_lock, flags); 1034 } 1035 1036 static struct audit_buffer * audit_buffer_alloc(struct audit_context *ctx, 1037 gfp_t gfp_mask, int type) 1038 { 1039 unsigned long flags; 1040 struct audit_buffer *ab = NULL; 1041 struct nlmsghdr *nlh; 1042 1043 spin_lock_irqsave(&audit_freelist_lock, flags); 1044 if (!list_empty(&audit_freelist)) { 1045 ab = list_entry(audit_freelist.next, 1046 struct audit_buffer, list); 1047 list_del(&ab->list); 1048 --audit_freelist_count; 1049 } 1050 spin_unlock_irqrestore(&audit_freelist_lock, flags); 1051 1052 if (!ab) { 1053 ab = kmalloc(sizeof(*ab), gfp_mask); 1054 if (!ab) 1055 goto err; 1056 } 1057 1058 ab->ctx = ctx; 1059 ab->gfp_mask = gfp_mask; 1060 1061 ab->skb = nlmsg_new(AUDIT_BUFSIZ, gfp_mask); 1062 if (!ab->skb) 1063 goto nlmsg_failure; 1064 1065 nlh = NLMSG_NEW(ab->skb, 0, 0, type, 0, 0); 1066 1067 return ab; 1068 1069 nlmsg_failure: /* Used by NLMSG_NEW */ 1070 kfree_skb(ab->skb); 1071 ab->skb = NULL; 1072 err: 1073 audit_buffer_free(ab); 1074 return NULL; 1075 } 1076 1077 /** 1078 * audit_serial - compute a serial number for the audit record 1079 * 1080 * Compute a serial number for the audit record. Audit records are 1081 * written to user-space as soon as they are generated, so a complete 1082 * audit record may be written in several pieces. The timestamp of the 1083 * record and this serial number are used by the user-space tools to 1084 * determine which pieces belong to the same audit record. The 1085 * (timestamp,serial) tuple is unique for each syscall and is live from 1086 * syscall entry to syscall exit. 1087 * 1088 * NOTE: Another possibility is to store the formatted records off the 1089 * audit context (for those records that have a context), and emit them 1090 * all at syscall exit. However, this could delay the reporting of 1091 * significant errors until syscall exit (or never, if the system 1092 * halts). 1093 */ 1094 unsigned int audit_serial(void) 1095 { 1096 static DEFINE_SPINLOCK(serial_lock); 1097 static unsigned int serial = 0; 1098 1099 unsigned long flags; 1100 unsigned int ret; 1101 1102 spin_lock_irqsave(&serial_lock, flags); 1103 do { 1104 ret = ++serial; 1105 } while (unlikely(!ret)); 1106 spin_unlock_irqrestore(&serial_lock, flags); 1107 1108 return ret; 1109 } 1110 1111 static inline void audit_get_stamp(struct audit_context *ctx, 1112 struct timespec *t, unsigned int *serial) 1113 { 1114 if (!ctx || !auditsc_get_stamp(ctx, t, serial)) { 1115 *t = CURRENT_TIME; 1116 *serial = audit_serial(); 1117 } 1118 } 1119 1120 /* Obtain an audit buffer. This routine does locking to obtain the 1121 * audit buffer, but then no locking is required for calls to 1122 * audit_log_*format. If the tsk is a task that is currently in a 1123 * syscall, then the syscall is marked as auditable and an audit record 1124 * will be written at syscall exit. If there is no associated task, tsk 1125 * should be NULL. */ 1126 1127 /** 1128 * audit_log_start - obtain an audit buffer 1129 * @ctx: audit_context (may be NULL) 1130 * @gfp_mask: type of allocation 1131 * @type: audit message type 1132 * 1133 * Returns audit_buffer pointer on success or NULL on error. 1134 * 1135 * Obtain an audit buffer. This routine does locking to obtain the 1136 * audit buffer, but then no locking is required for calls to 1137 * audit_log_*format. If the task (ctx) is a task that is currently in a 1138 * syscall, then the syscall is marked as auditable and an audit record 1139 * will be written at syscall exit. If there is no associated task, then 1140 * task context (ctx) should be NULL. 1141 */ 1142 struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask, 1143 int type) 1144 { 1145 struct audit_buffer *ab = NULL; 1146 struct timespec t; 1147 unsigned int uninitialized_var(serial); 1148 int reserve; 1149 unsigned long timeout_start = jiffies; 1150 1151 if (audit_initialized != AUDIT_INITIALIZED) 1152 return NULL; 1153 1154 if (unlikely(audit_filter_type(type))) 1155 return NULL; 1156 1157 if (gfp_mask & __GFP_WAIT) 1158 reserve = 0; 1159 else 1160 reserve = 5; /* Allow atomic callers to go up to five 1161 entries over the normal backlog limit */ 1162 1163 while (audit_backlog_limit 1164 && skb_queue_len(&audit_skb_queue) > audit_backlog_limit + reserve) { 1165 if (gfp_mask & __GFP_WAIT && audit_backlog_wait_time 1166 && time_before(jiffies, timeout_start + audit_backlog_wait_time)) { 1167 1168 /* Wait for auditd to drain the queue a little */ 1169 DECLARE_WAITQUEUE(wait, current); 1170 set_current_state(TASK_INTERRUPTIBLE); 1171 add_wait_queue(&audit_backlog_wait, &wait); 1172 1173 if (audit_backlog_limit && 1174 skb_queue_len(&audit_skb_queue) > audit_backlog_limit) 1175 schedule_timeout(timeout_start + audit_backlog_wait_time - jiffies); 1176 1177 __set_current_state(TASK_RUNNING); 1178 remove_wait_queue(&audit_backlog_wait, &wait); 1179 continue; 1180 } 1181 if (audit_rate_check() && printk_ratelimit()) 1182 printk(KERN_WARNING 1183 "audit: audit_backlog=%d > " 1184 "audit_backlog_limit=%d\n", 1185 skb_queue_len(&audit_skb_queue), 1186 audit_backlog_limit); 1187 audit_log_lost("backlog limit exceeded"); 1188 audit_backlog_wait_time = audit_backlog_wait_overflow; 1189 wake_up(&audit_backlog_wait); 1190 return NULL; 1191 } 1192 1193 ab = audit_buffer_alloc(ctx, gfp_mask, type); 1194 if (!ab) { 1195 audit_log_lost("out of memory in audit_log_start"); 1196 return NULL; 1197 } 1198 1199 audit_get_stamp(ab->ctx, &t, &serial); 1200 1201 audit_log_format(ab, "audit(%lu.%03lu:%u): ", 1202 t.tv_sec, t.tv_nsec/1000000, serial); 1203 return ab; 1204 } 1205 1206 /** 1207 * audit_expand - expand skb in the audit buffer 1208 * @ab: audit_buffer 1209 * @extra: space to add at tail of the skb 1210 * 1211 * Returns 0 (no space) on failed expansion, or available space if 1212 * successful. 1213 */ 1214 static inline int audit_expand(struct audit_buffer *ab, int extra) 1215 { 1216 struct sk_buff *skb = ab->skb; 1217 int oldtail = skb_tailroom(skb); 1218 int ret = pskb_expand_head(skb, 0, extra, ab->gfp_mask); 1219 int newtail = skb_tailroom(skb); 1220 1221 if (ret < 0) { 1222 audit_log_lost("out of memory in audit_expand"); 1223 return 0; 1224 } 1225 1226 skb->truesize += newtail - oldtail; 1227 return newtail; 1228 } 1229 1230 /* 1231 * Format an audit message into the audit buffer. If there isn't enough 1232 * room in the audit buffer, more room will be allocated and vsnprint 1233 * will be called a second time. Currently, we assume that a printk 1234 * can't format message larger than 1024 bytes, so we don't either. 1235 */ 1236 static void audit_log_vformat(struct audit_buffer *ab, const char *fmt, 1237 va_list args) 1238 { 1239 int len, avail; 1240 struct sk_buff *skb; 1241 va_list args2; 1242 1243 if (!ab) 1244 return; 1245 1246 BUG_ON(!ab->skb); 1247 skb = ab->skb; 1248 avail = skb_tailroom(skb); 1249 if (avail == 0) { 1250 avail = audit_expand(ab, AUDIT_BUFSIZ); 1251 if (!avail) 1252 goto out; 1253 } 1254 va_copy(args2, args); 1255 len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args); 1256 if (len >= avail) { 1257 /* The printk buffer is 1024 bytes long, so if we get 1258 * here and AUDIT_BUFSIZ is at least 1024, then we can 1259 * log everything that printk could have logged. */ 1260 avail = audit_expand(ab, 1261 max_t(unsigned, AUDIT_BUFSIZ, 1+len-avail)); 1262 if (!avail) 1263 goto out; 1264 len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args2); 1265 } 1266 va_end(args2); 1267 if (len > 0) 1268 skb_put(skb, len); 1269 out: 1270 return; 1271 } 1272 1273 /** 1274 * audit_log_format - format a message into the audit buffer. 1275 * @ab: audit_buffer 1276 * @fmt: format string 1277 * @...: optional parameters matching @fmt string 1278 * 1279 * All the work is done in audit_log_vformat. 1280 */ 1281 void audit_log_format(struct audit_buffer *ab, const char *fmt, ...) 1282 { 1283 va_list args; 1284 1285 if (!ab) 1286 return; 1287 va_start(args, fmt); 1288 audit_log_vformat(ab, fmt, args); 1289 va_end(args); 1290 } 1291 1292 /** 1293 * audit_log_hex - convert a buffer to hex and append it to the audit skb 1294 * @ab: the audit_buffer 1295 * @buf: buffer to convert to hex 1296 * @len: length of @buf to be converted 1297 * 1298 * No return value; failure to expand is silently ignored. 1299 * 1300 * This function will take the passed buf and convert it into a string of 1301 * ascii hex digits. The new string is placed onto the skb. 1302 */ 1303 void audit_log_n_hex(struct audit_buffer *ab, const unsigned char *buf, 1304 size_t len) 1305 { 1306 int i, avail, new_len; 1307 unsigned char *ptr; 1308 struct sk_buff *skb; 1309 static const unsigned char *hex = "0123456789ABCDEF"; 1310 1311 if (!ab) 1312 return; 1313 1314 BUG_ON(!ab->skb); 1315 skb = ab->skb; 1316 avail = skb_tailroom(skb); 1317 new_len = len<<1; 1318 if (new_len >= avail) { 1319 /* Round the buffer request up to the next multiple */ 1320 new_len = AUDIT_BUFSIZ*(((new_len-avail)/AUDIT_BUFSIZ) + 1); 1321 avail = audit_expand(ab, new_len); 1322 if (!avail) 1323 return; 1324 } 1325 1326 ptr = skb_tail_pointer(skb); 1327 for (i=0; i<len; i++) { 1328 *ptr++ = hex[(buf[i] & 0xF0)>>4]; /* Upper nibble */ 1329 *ptr++ = hex[buf[i] & 0x0F]; /* Lower nibble */ 1330 } 1331 *ptr = 0; 1332 skb_put(skb, len << 1); /* new string is twice the old string */ 1333 } 1334 1335 /* 1336 * Format a string of no more than slen characters into the audit buffer, 1337 * enclosed in quote marks. 1338 */ 1339 void audit_log_n_string(struct audit_buffer *ab, const char *string, 1340 size_t slen) 1341 { 1342 int avail, new_len; 1343 unsigned char *ptr; 1344 struct sk_buff *skb; 1345 1346 if (!ab) 1347 return; 1348 1349 BUG_ON(!ab->skb); 1350 skb = ab->skb; 1351 avail = skb_tailroom(skb); 1352 new_len = slen + 3; /* enclosing quotes + null terminator */ 1353 if (new_len > avail) { 1354 avail = audit_expand(ab, new_len); 1355 if (!avail) 1356 return; 1357 } 1358 ptr = skb_tail_pointer(skb); 1359 *ptr++ = '"'; 1360 memcpy(ptr, string, slen); 1361 ptr += slen; 1362 *ptr++ = '"'; 1363 *ptr = 0; 1364 skb_put(skb, slen + 2); /* don't include null terminator */ 1365 } 1366 1367 /** 1368 * audit_string_contains_control - does a string need to be logged in hex 1369 * @string: string to be checked 1370 * @len: max length of the string to check 1371 */ 1372 int audit_string_contains_control(const char *string, size_t len) 1373 { 1374 const unsigned char *p; 1375 for (p = string; p < (const unsigned char *)string + len; p++) { 1376 if (*p == '"' || *p < 0x21 || *p > 0x7e) 1377 return 1; 1378 } 1379 return 0; 1380 } 1381 1382 /** 1383 * audit_log_n_untrustedstring - log a string that may contain random characters 1384 * @ab: audit_buffer 1385 * @len: length of string (not including trailing null) 1386 * @string: string to be logged 1387 * 1388 * This code will escape a string that is passed to it if the string 1389 * contains a control character, unprintable character, double quote mark, 1390 * or a space. Unescaped strings will start and end with a double quote mark. 1391 * Strings that are escaped are printed in hex (2 digits per char). 1392 * 1393 * The caller specifies the number of characters in the string to log, which may 1394 * or may not be the entire string. 1395 */ 1396 void audit_log_n_untrustedstring(struct audit_buffer *ab, const char *string, 1397 size_t len) 1398 { 1399 if (audit_string_contains_control(string, len)) 1400 audit_log_n_hex(ab, string, len); 1401 else 1402 audit_log_n_string(ab, string, len); 1403 } 1404 1405 /** 1406 * audit_log_untrustedstring - log a string that may contain random characters 1407 * @ab: audit_buffer 1408 * @string: string to be logged 1409 * 1410 * Same as audit_log_n_untrustedstring(), except that strlen is used to 1411 * determine string length. 1412 */ 1413 void audit_log_untrustedstring(struct audit_buffer *ab, const char *string) 1414 { 1415 audit_log_n_untrustedstring(ab, string, strlen(string)); 1416 } 1417 1418 /* This is a helper-function to print the escaped d_path */ 1419 void audit_log_d_path(struct audit_buffer *ab, const char *prefix, 1420 struct path *path) 1421 { 1422 char *p, *pathname; 1423 1424 if (prefix) 1425 audit_log_format(ab, " %s", prefix); 1426 1427 /* We will allow 11 spaces for ' (deleted)' to be appended */ 1428 pathname = kmalloc(PATH_MAX+11, ab->gfp_mask); 1429 if (!pathname) { 1430 audit_log_string(ab, "<no_memory>"); 1431 return; 1432 } 1433 p = d_path(path, pathname, PATH_MAX+11); 1434 if (IS_ERR(p)) { /* Should never happen since we send PATH_MAX */ 1435 /* FIXME: can we save some information here? */ 1436 audit_log_string(ab, "<too_long>"); 1437 } else 1438 audit_log_untrustedstring(ab, p); 1439 kfree(pathname); 1440 } 1441 1442 void audit_log_key(struct audit_buffer *ab, char *key) 1443 { 1444 audit_log_format(ab, " key="); 1445 if (key) 1446 audit_log_untrustedstring(ab, key); 1447 else 1448 audit_log_format(ab, "(null)"); 1449 } 1450 1451 /** 1452 * audit_log_end - end one audit record 1453 * @ab: the audit_buffer 1454 * 1455 * The netlink_* functions cannot be called inside an irq context, so 1456 * the audit buffer is placed on a queue and a tasklet is scheduled to 1457 * remove them from the queue outside the irq context. May be called in 1458 * any context. 1459 */ 1460 void audit_log_end(struct audit_buffer *ab) 1461 { 1462 if (!ab) 1463 return; 1464 if (!audit_rate_check()) { 1465 audit_log_lost("rate limit exceeded"); 1466 } else { 1467 struct nlmsghdr *nlh = nlmsg_hdr(ab->skb); 1468 nlh->nlmsg_len = ab->skb->len - NLMSG_SPACE(0); 1469 1470 if (audit_pid) { 1471 skb_queue_tail(&audit_skb_queue, ab->skb); 1472 wake_up_interruptible(&kauditd_wait); 1473 } else { 1474 audit_printk_skb(ab->skb); 1475 } 1476 ab->skb = NULL; 1477 } 1478 audit_buffer_free(ab); 1479 } 1480 1481 /** 1482 * audit_log - Log an audit record 1483 * @ctx: audit context 1484 * @gfp_mask: type of allocation 1485 * @type: audit message type 1486 * @fmt: format string to use 1487 * @...: variable parameters matching the format string 1488 * 1489 * This is a convenience function that calls audit_log_start, 1490 * audit_log_vformat, and audit_log_end. It may be called 1491 * in any context. 1492 */ 1493 void audit_log(struct audit_context *ctx, gfp_t gfp_mask, int type, 1494 const char *fmt, ...) 1495 { 1496 struct audit_buffer *ab; 1497 va_list args; 1498 1499 ab = audit_log_start(ctx, gfp_mask, type); 1500 if (ab) { 1501 va_start(args, fmt); 1502 audit_log_vformat(ab, fmt, args); 1503 va_end(args); 1504 audit_log_end(ab); 1505 } 1506 } 1507 1508 #ifdef CONFIG_SECURITY 1509 /** 1510 * audit_log_secctx - Converts and logs SELinux context 1511 * @ab: audit_buffer 1512 * @secid: security number 1513 * 1514 * This is a helper function that calls security_secid_to_secctx to convert 1515 * secid to secctx and then adds the (converted) SELinux context to the audit 1516 * log by calling audit_log_format, thus also preventing leak of internal secid 1517 * to userspace. If secid cannot be converted audit_panic is called. 1518 */ 1519 void audit_log_secctx(struct audit_buffer *ab, u32 secid) 1520 { 1521 u32 len; 1522 char *secctx; 1523 1524 if (security_secid_to_secctx(secid, &secctx, &len)) { 1525 audit_panic("Cannot convert secid to context"); 1526 } else { 1527 audit_log_format(ab, " obj=%s", secctx); 1528 security_release_secctx(secctx, len); 1529 } 1530 } 1531 EXPORT_SYMBOL(audit_log_secctx); 1532 #endif 1533 1534 EXPORT_SYMBOL(audit_log_start); 1535 EXPORT_SYMBOL(audit_log_end); 1536 EXPORT_SYMBOL(audit_log_format); 1537 EXPORT_SYMBOL(audit_log); 1538