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