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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 45 46 #include <linux/file.h> 47 #include <linux/init.h> 48 #include <linux/types.h> 49 #include <linux/atomic.h> 50 #include <linux/mm.h> 51 #include <linux/export.h> 52 #include <linux/slab.h> 53 #include <linux/err.h> 54 #include <linux/kthread.h> 55 #include <linux/kernel.h> 56 #include <linux/syscalls.h> 57 58 #include <linux/audit.h> 59 60 #include <net/sock.h> 61 #include <net/netlink.h> 62 #include <linux/skbuff.h> 63 #ifdef CONFIG_SECURITY 64 #include <linux/security.h> 65 #endif 66 #include <linux/freezer.h> 67 #include <linux/pid_namespace.h> 68 #include <net/netns/generic.h> 69 70 #include "audit.h" 71 72 /* No auditing will take place until audit_initialized == AUDIT_INITIALIZED. 73 * (Initialization happens after skb_init is called.) */ 74 #define AUDIT_DISABLED -1 75 #define AUDIT_UNINITIALIZED 0 76 #define AUDIT_INITIALIZED 1 77 static int audit_initialized; 78 79 #define AUDIT_OFF 0 80 #define AUDIT_ON 1 81 #define AUDIT_LOCKED 2 82 u32 audit_enabled; 83 u32 audit_ever_enabled; 84 85 EXPORT_SYMBOL_GPL(audit_enabled); 86 87 /* Default state when kernel boots without any parameters. */ 88 static u32 audit_default; 89 90 /* If auditing cannot proceed, audit_failure selects what happens. */ 91 static u32 audit_failure = AUDIT_FAIL_PRINTK; 92 93 /* 94 * If audit records are to be written to the netlink socket, audit_pid 95 * contains the pid of the auditd process and audit_nlk_portid contains 96 * the portid to use to send netlink messages to that process. 97 */ 98 int audit_pid; 99 static __u32 audit_nlk_portid; 100 101 /* If audit_rate_limit is non-zero, limit the rate of sending audit records 102 * to that number per second. This prevents DoS attacks, but results in 103 * audit records being dropped. */ 104 static u32 audit_rate_limit; 105 106 /* Number of outstanding audit_buffers allowed. 107 * When set to zero, this means unlimited. */ 108 static u32 audit_backlog_limit = 64; 109 #define AUDIT_BACKLOG_WAIT_TIME (60 * HZ) 110 static u32 audit_backlog_wait_time_master = AUDIT_BACKLOG_WAIT_TIME; 111 static u32 audit_backlog_wait_time = AUDIT_BACKLOG_WAIT_TIME; 112 113 /* The identity of the user shutting down the audit system. */ 114 kuid_t audit_sig_uid = INVALID_UID; 115 pid_t audit_sig_pid = -1; 116 u32 audit_sig_sid = 0; 117 118 /* Records can be lost in several ways: 119 0) [suppressed in audit_alloc] 120 1) out of memory in audit_log_start [kmalloc of struct audit_buffer] 121 2) out of memory in audit_log_move [alloc_skb] 122 3) suppressed due to audit_rate_limit 123 4) suppressed due to audit_backlog_limit 124 */ 125 static atomic_t audit_lost = ATOMIC_INIT(0); 126 127 /* The netlink socket. */ 128 static struct sock *audit_sock; 129 static int audit_net_id; 130 131 /* Hash for inode-based rules */ 132 struct list_head audit_inode_hash[AUDIT_INODE_BUCKETS]; 133 134 /* The audit_freelist is a list of pre-allocated audit buffers (if more 135 * than AUDIT_MAXFREE are in use, the audit buffer is freed instead of 136 * being placed on the freelist). */ 137 static DEFINE_SPINLOCK(audit_freelist_lock); 138 static int audit_freelist_count; 139 static LIST_HEAD(audit_freelist); 140 141 static struct sk_buff_head audit_skb_queue; 142 /* queue of skbs to send to auditd when/if it comes back */ 143 static struct sk_buff_head audit_skb_hold_queue; 144 static struct task_struct *kauditd_task; 145 static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait); 146 static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait); 147 148 static struct audit_features af = {.vers = AUDIT_FEATURE_VERSION, 149 .mask = -1, 150 .features = 0, 151 .lock = 0,}; 152 153 static char *audit_feature_names[2] = { 154 "only_unset_loginuid", 155 "loginuid_immutable", 156 }; 157 158 159 /* Serialize requests from userspace. */ 160 DEFINE_MUTEX(audit_cmd_mutex); 161 162 /* AUDIT_BUFSIZ is the size of the temporary buffer used for formatting 163 * audit records. Since printk uses a 1024 byte buffer, this buffer 164 * should be at least that large. */ 165 #define AUDIT_BUFSIZ 1024 166 167 /* AUDIT_MAXFREE is the number of empty audit_buffers we keep on the 168 * audit_freelist. Doing so eliminates many kmalloc/kfree calls. */ 169 #define AUDIT_MAXFREE (2*NR_CPUS) 170 171 /* The audit_buffer is used when formatting an audit record. The caller 172 * locks briefly to get the record off the freelist or to allocate the 173 * buffer, and locks briefly to send the buffer to the netlink layer or 174 * to place it on a transmit queue. Multiple audit_buffers can be in 175 * use simultaneously. */ 176 struct audit_buffer { 177 struct list_head list; 178 struct sk_buff *skb; /* formatted skb ready to send */ 179 struct audit_context *ctx; /* NULL or associated context */ 180 gfp_t gfp_mask; 181 }; 182 183 struct audit_reply { 184 __u32 portid; 185 struct net *net; 186 struct sk_buff *skb; 187 }; 188 189 static void audit_set_portid(struct audit_buffer *ab, __u32 portid) 190 { 191 if (ab) { 192 struct nlmsghdr *nlh = nlmsg_hdr(ab->skb); 193 nlh->nlmsg_pid = portid; 194 } 195 } 196 197 void audit_panic(const char *message) 198 { 199 switch (audit_failure) { 200 case AUDIT_FAIL_SILENT: 201 break; 202 case AUDIT_FAIL_PRINTK: 203 if (printk_ratelimit()) 204 pr_err("%s\n", message); 205 break; 206 case AUDIT_FAIL_PANIC: 207 /* test audit_pid since printk is always losey, why bother? */ 208 if (audit_pid) 209 panic("audit: %s\n", message); 210 break; 211 } 212 } 213 214 static inline int audit_rate_check(void) 215 { 216 static unsigned long last_check = 0; 217 static int messages = 0; 218 static DEFINE_SPINLOCK(lock); 219 unsigned long flags; 220 unsigned long now; 221 unsigned long elapsed; 222 int retval = 0; 223 224 if (!audit_rate_limit) return 1; 225 226 spin_lock_irqsave(&lock, flags); 227 if (++messages < audit_rate_limit) { 228 retval = 1; 229 } else { 230 now = jiffies; 231 elapsed = now - last_check; 232 if (elapsed > HZ) { 233 last_check = now; 234 messages = 0; 235 retval = 1; 236 } 237 } 238 spin_unlock_irqrestore(&lock, flags); 239 240 return retval; 241 } 242 243 /** 244 * audit_log_lost - conditionally log lost audit message event 245 * @message: the message stating reason for lost audit message 246 * 247 * Emit at least 1 message per second, even if audit_rate_check is 248 * throttling. 249 * Always increment the lost messages counter. 250 */ 251 void audit_log_lost(const char *message) 252 { 253 static unsigned long last_msg = 0; 254 static DEFINE_SPINLOCK(lock); 255 unsigned long flags; 256 unsigned long now; 257 int print; 258 259 atomic_inc(&audit_lost); 260 261 print = (audit_failure == AUDIT_FAIL_PANIC || !audit_rate_limit); 262 263 if (!print) { 264 spin_lock_irqsave(&lock, flags); 265 now = jiffies; 266 if (now - last_msg > HZ) { 267 print = 1; 268 last_msg = now; 269 } 270 spin_unlock_irqrestore(&lock, flags); 271 } 272 273 if (print) { 274 if (printk_ratelimit()) 275 pr_warn("audit_lost=%u audit_rate_limit=%u audit_backlog_limit=%u\n", 276 atomic_read(&audit_lost), 277 audit_rate_limit, 278 audit_backlog_limit); 279 audit_panic(message); 280 } 281 } 282 283 static int audit_log_config_change(char *function_name, u32 new, u32 old, 284 int allow_changes) 285 { 286 struct audit_buffer *ab; 287 int rc = 0; 288 289 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE); 290 if (unlikely(!ab)) 291 return rc; 292 audit_log_format(ab, "%s=%u old=%u", function_name, new, old); 293 audit_log_session_info(ab); 294 rc = audit_log_task_context(ab); 295 if (rc) 296 allow_changes = 0; /* Something weird, deny request */ 297 audit_log_format(ab, " res=%d", allow_changes); 298 audit_log_end(ab); 299 return rc; 300 } 301 302 static int audit_do_config_change(char *function_name, u32 *to_change, u32 new) 303 { 304 int allow_changes, rc = 0; 305 u32 old = *to_change; 306 307 /* check if we are locked */ 308 if (audit_enabled == AUDIT_LOCKED) 309 allow_changes = 0; 310 else 311 allow_changes = 1; 312 313 if (audit_enabled != AUDIT_OFF) { 314 rc = audit_log_config_change(function_name, new, old, allow_changes); 315 if (rc) 316 allow_changes = 0; 317 } 318 319 /* If we are allowed, make the change */ 320 if (allow_changes == 1) 321 *to_change = new; 322 /* Not allowed, update reason */ 323 else if (rc == 0) 324 rc = -EPERM; 325 return rc; 326 } 327 328 static int audit_set_rate_limit(u32 limit) 329 { 330 return audit_do_config_change("audit_rate_limit", &audit_rate_limit, limit); 331 } 332 333 static int audit_set_backlog_limit(u32 limit) 334 { 335 return audit_do_config_change("audit_backlog_limit", &audit_backlog_limit, limit); 336 } 337 338 static int audit_set_backlog_wait_time(u32 timeout) 339 { 340 return audit_do_config_change("audit_backlog_wait_time", 341 &audit_backlog_wait_time_master, timeout); 342 } 343 344 static int audit_set_enabled(u32 state) 345 { 346 int rc; 347 if (state > AUDIT_LOCKED) 348 return -EINVAL; 349 350 rc = audit_do_config_change("audit_enabled", &audit_enabled, state); 351 if (!rc) 352 audit_ever_enabled |= !!state; 353 354 return rc; 355 } 356 357 static int audit_set_failure(u32 state) 358 { 359 if (state != AUDIT_FAIL_SILENT 360 && state != AUDIT_FAIL_PRINTK 361 && state != AUDIT_FAIL_PANIC) 362 return -EINVAL; 363 364 return audit_do_config_change("audit_failure", &audit_failure, state); 365 } 366 367 /* 368 * Queue skbs to be sent to auditd when/if it comes back. These skbs should 369 * already have been sent via prink/syslog and so if these messages are dropped 370 * it is not a huge concern since we already passed the audit_log_lost() 371 * notification and stuff. This is just nice to get audit messages during 372 * boot before auditd is running or messages generated while auditd is stopped. 373 * This only holds messages is audit_default is set, aka booting with audit=1 374 * or building your kernel that way. 375 */ 376 static void audit_hold_skb(struct sk_buff *skb) 377 { 378 if (audit_default && 379 (!audit_backlog_limit || 380 skb_queue_len(&audit_skb_hold_queue) < audit_backlog_limit)) 381 skb_queue_tail(&audit_skb_hold_queue, skb); 382 else 383 kfree_skb(skb); 384 } 385 386 /* 387 * For one reason or another this nlh isn't getting delivered to the userspace 388 * audit daemon, just send it to printk. 389 */ 390 static void audit_printk_skb(struct sk_buff *skb) 391 { 392 struct nlmsghdr *nlh = nlmsg_hdr(skb); 393 char *data = nlmsg_data(nlh); 394 395 if (nlh->nlmsg_type != AUDIT_EOE) { 396 if (printk_ratelimit()) 397 pr_notice("type=%d %s\n", nlh->nlmsg_type, data); 398 else 399 audit_log_lost("printk limit exceeded"); 400 } 401 402 audit_hold_skb(skb); 403 } 404 405 static void kauditd_send_skb(struct sk_buff *skb) 406 { 407 int err; 408 int attempts = 0; 409 #define AUDITD_RETRIES 5 410 411 restart: 412 /* take a reference in case we can't send it and we want to hold it */ 413 skb_get(skb); 414 err = netlink_unicast(audit_sock, skb, audit_nlk_portid, 0); 415 if (err < 0) { 416 pr_err("netlink_unicast sending to audit_pid=%d returned error: %d\n", 417 audit_pid, err); 418 if (audit_pid) { 419 if (err == -ECONNREFUSED || err == -EPERM 420 || ++attempts >= AUDITD_RETRIES) { 421 char s[32]; 422 423 snprintf(s, sizeof(s), "audit_pid=%d reset", audit_pid); 424 audit_log_lost(s); 425 audit_pid = 0; 426 audit_sock = NULL; 427 } else { 428 pr_warn("re-scheduling(#%d) write to audit_pid=%d\n", 429 attempts, audit_pid); 430 set_current_state(TASK_INTERRUPTIBLE); 431 schedule(); 432 goto restart; 433 } 434 } 435 /* we might get lucky and get this in the next auditd */ 436 audit_hold_skb(skb); 437 } else 438 /* drop the extra reference if sent ok */ 439 consume_skb(skb); 440 } 441 442 /* 443 * kauditd_send_multicast_skb - send the skb to multicast userspace listeners 444 * 445 * This function doesn't consume an skb as might be expected since it has to 446 * copy it anyways. 447 */ 448 static void kauditd_send_multicast_skb(struct sk_buff *skb, gfp_t gfp_mask) 449 { 450 struct sk_buff *copy; 451 struct audit_net *aunet = net_generic(&init_net, audit_net_id); 452 struct sock *sock = aunet->nlsk; 453 454 if (!netlink_has_listeners(sock, AUDIT_NLGRP_READLOG)) 455 return; 456 457 /* 458 * The seemingly wasteful skb_copy() rather than bumping the refcount 459 * using skb_get() is necessary because non-standard mods are made to 460 * the skb by the original kaudit unicast socket send routine. The 461 * existing auditd daemon assumes this breakage. Fixing this would 462 * require co-ordinating a change in the established protocol between 463 * the kaudit kernel subsystem and the auditd userspace code. There is 464 * no reason for new multicast clients to continue with this 465 * non-compliance. 466 */ 467 copy = skb_copy(skb, gfp_mask); 468 if (!copy) 469 return; 470 471 nlmsg_multicast(sock, copy, 0, AUDIT_NLGRP_READLOG, gfp_mask); 472 } 473 474 /* 475 * flush_hold_queue - empty the hold queue if auditd appears 476 * 477 * If auditd just started, drain the queue of messages already 478 * sent to syslog/printk. Remember loss here is ok. We already 479 * called audit_log_lost() if it didn't go out normally. so the 480 * race between the skb_dequeue and the next check for audit_pid 481 * doesn't matter. 482 * 483 * If you ever find kauditd to be too slow we can get a perf win 484 * by doing our own locking and keeping better track if there 485 * are messages in this queue. I don't see the need now, but 486 * in 5 years when I want to play with this again I'll see this 487 * note and still have no friggin idea what i'm thinking today. 488 */ 489 static void flush_hold_queue(void) 490 { 491 struct sk_buff *skb; 492 493 if (!audit_default || !audit_pid) 494 return; 495 496 skb = skb_dequeue(&audit_skb_hold_queue); 497 if (likely(!skb)) 498 return; 499 500 while (skb && audit_pid) { 501 kauditd_send_skb(skb); 502 skb = skb_dequeue(&audit_skb_hold_queue); 503 } 504 505 /* 506 * if auditd just disappeared but we 507 * dequeued an skb we need to drop ref 508 */ 509 consume_skb(skb); 510 } 511 512 static int kauditd_thread(void *dummy) 513 { 514 set_freezable(); 515 while (!kthread_should_stop()) { 516 struct sk_buff *skb; 517 518 flush_hold_queue(); 519 520 skb = skb_dequeue(&audit_skb_queue); 521 522 if (skb) { 523 if (!audit_backlog_limit || 524 (skb_queue_len(&audit_skb_queue) <= audit_backlog_limit)) 525 wake_up(&audit_backlog_wait); 526 if (audit_pid) 527 kauditd_send_skb(skb); 528 else 529 audit_printk_skb(skb); 530 continue; 531 } 532 533 wait_event_freezable(kauditd_wait, skb_queue_len(&audit_skb_queue)); 534 } 535 return 0; 536 } 537 538 int audit_send_list(void *_dest) 539 { 540 struct audit_netlink_list *dest = _dest; 541 struct sk_buff *skb; 542 struct net *net = dest->net; 543 struct audit_net *aunet = net_generic(net, audit_net_id); 544 545 /* wait for parent to finish and send an ACK */ 546 mutex_lock(&audit_cmd_mutex); 547 mutex_unlock(&audit_cmd_mutex); 548 549 while ((skb = __skb_dequeue(&dest->q)) != NULL) 550 netlink_unicast(aunet->nlsk, skb, dest->portid, 0); 551 552 put_net(net); 553 kfree(dest); 554 555 return 0; 556 } 557 558 struct sk_buff *audit_make_reply(__u32 portid, int seq, int type, int done, 559 int multi, const void *payload, int size) 560 { 561 struct sk_buff *skb; 562 struct nlmsghdr *nlh; 563 void *data; 564 int flags = multi ? NLM_F_MULTI : 0; 565 int t = done ? NLMSG_DONE : type; 566 567 skb = nlmsg_new(size, GFP_KERNEL); 568 if (!skb) 569 return NULL; 570 571 nlh = nlmsg_put(skb, portid, seq, t, size, flags); 572 if (!nlh) 573 goto out_kfree_skb; 574 data = nlmsg_data(nlh); 575 memcpy(data, payload, size); 576 return skb; 577 578 out_kfree_skb: 579 kfree_skb(skb); 580 return NULL; 581 } 582 583 static int audit_send_reply_thread(void *arg) 584 { 585 struct audit_reply *reply = (struct audit_reply *)arg; 586 struct net *net = reply->net; 587 struct audit_net *aunet = net_generic(net, audit_net_id); 588 589 mutex_lock(&audit_cmd_mutex); 590 mutex_unlock(&audit_cmd_mutex); 591 592 /* Ignore failure. It'll only happen if the sender goes away, 593 because our timeout is set to infinite. */ 594 netlink_unicast(aunet->nlsk , reply->skb, reply->portid, 0); 595 put_net(net); 596 kfree(reply); 597 return 0; 598 } 599 /** 600 * audit_send_reply - send an audit reply message via netlink 601 * @request_skb: skb of request we are replying to (used to target the reply) 602 * @seq: sequence number 603 * @type: audit message type 604 * @done: done (last) flag 605 * @multi: multi-part message flag 606 * @payload: payload data 607 * @size: payload size 608 * 609 * Allocates an skb, builds the netlink message, and sends it to the port id. 610 * No failure notifications. 611 */ 612 static void audit_send_reply(struct sk_buff *request_skb, int seq, int type, int done, 613 int multi, const void *payload, int size) 614 { 615 u32 portid = NETLINK_CB(request_skb).portid; 616 struct net *net = sock_net(NETLINK_CB(request_skb).sk); 617 struct sk_buff *skb; 618 struct task_struct *tsk; 619 struct audit_reply *reply = kmalloc(sizeof(struct audit_reply), 620 GFP_KERNEL); 621 622 if (!reply) 623 return; 624 625 skb = audit_make_reply(portid, seq, type, done, multi, payload, size); 626 if (!skb) 627 goto out; 628 629 reply->net = get_net(net); 630 reply->portid = portid; 631 reply->skb = skb; 632 633 tsk = kthread_run(audit_send_reply_thread, reply, "audit_send_reply"); 634 if (!IS_ERR(tsk)) 635 return; 636 kfree_skb(skb); 637 out: 638 kfree(reply); 639 } 640 641 /* 642 * Check for appropriate CAP_AUDIT_ capabilities on incoming audit 643 * control messages. 644 */ 645 static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type) 646 { 647 int err = 0; 648 649 /* Only support initial user namespace for now. */ 650 /* 651 * We return ECONNREFUSED because it tricks userspace into thinking 652 * that audit was not configured into the kernel. Lots of users 653 * configure their PAM stack (because that's what the distro does) 654 * to reject login if unable to send messages to audit. If we return 655 * ECONNREFUSED the PAM stack thinks the kernel does not have audit 656 * configured in and will let login proceed. If we return EPERM 657 * userspace will reject all logins. This should be removed when we 658 * support non init namespaces!! 659 */ 660 if (current_user_ns() != &init_user_ns) 661 return -ECONNREFUSED; 662 663 switch (msg_type) { 664 case AUDIT_LIST: 665 case AUDIT_ADD: 666 case AUDIT_DEL: 667 return -EOPNOTSUPP; 668 case AUDIT_GET: 669 case AUDIT_SET: 670 case AUDIT_GET_FEATURE: 671 case AUDIT_SET_FEATURE: 672 case AUDIT_LIST_RULES: 673 case AUDIT_ADD_RULE: 674 case AUDIT_DEL_RULE: 675 case AUDIT_SIGNAL_INFO: 676 case AUDIT_TTY_GET: 677 case AUDIT_TTY_SET: 678 case AUDIT_TRIM: 679 case AUDIT_MAKE_EQUIV: 680 /* Only support auditd and auditctl in initial pid namespace 681 * for now. */ 682 if (task_active_pid_ns(current) != &init_pid_ns) 683 return -EPERM; 684 685 if (!netlink_capable(skb, CAP_AUDIT_CONTROL)) 686 err = -EPERM; 687 break; 688 case AUDIT_USER: 689 case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG: 690 case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2: 691 if (!netlink_capable(skb, CAP_AUDIT_WRITE)) 692 err = -EPERM; 693 break; 694 default: /* bad msg */ 695 err = -EINVAL; 696 } 697 698 return err; 699 } 700 701 static void audit_log_common_recv_msg(struct audit_buffer **ab, u16 msg_type) 702 { 703 uid_t uid = from_kuid(&init_user_ns, current_uid()); 704 pid_t pid = task_tgid_nr(current); 705 706 if (!audit_enabled && msg_type != AUDIT_USER_AVC) { 707 *ab = NULL; 708 return; 709 } 710 711 *ab = audit_log_start(NULL, GFP_KERNEL, msg_type); 712 if (unlikely(!*ab)) 713 return; 714 audit_log_format(*ab, "pid=%d uid=%u", pid, uid); 715 audit_log_session_info(*ab); 716 audit_log_task_context(*ab); 717 } 718 719 int is_audit_feature_set(int i) 720 { 721 return af.features & AUDIT_FEATURE_TO_MASK(i); 722 } 723 724 725 static int audit_get_feature(struct sk_buff *skb) 726 { 727 u32 seq; 728 729 seq = nlmsg_hdr(skb)->nlmsg_seq; 730 731 audit_send_reply(skb, seq, AUDIT_GET_FEATURE, 0, 0, &af, sizeof(af)); 732 733 return 0; 734 } 735 736 static void audit_log_feature_change(int which, u32 old_feature, u32 new_feature, 737 u32 old_lock, u32 new_lock, int res) 738 { 739 struct audit_buffer *ab; 740 741 if (audit_enabled == AUDIT_OFF) 742 return; 743 744 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_FEATURE_CHANGE); 745 audit_log_task_info(ab, current); 746 audit_log_format(ab, " feature=%s old=%u new=%u old_lock=%u new_lock=%u res=%d", 747 audit_feature_names[which], !!old_feature, !!new_feature, 748 !!old_lock, !!new_lock, res); 749 audit_log_end(ab); 750 } 751 752 static int audit_set_feature(struct sk_buff *skb) 753 { 754 struct audit_features *uaf; 755 int i; 756 757 BUILD_BUG_ON(AUDIT_LAST_FEATURE + 1 > ARRAY_SIZE(audit_feature_names)); 758 uaf = nlmsg_data(nlmsg_hdr(skb)); 759 760 /* if there is ever a version 2 we should handle that here */ 761 762 for (i = 0; i <= AUDIT_LAST_FEATURE; i++) { 763 u32 feature = AUDIT_FEATURE_TO_MASK(i); 764 u32 old_feature, new_feature, old_lock, new_lock; 765 766 /* if we are not changing this feature, move along */ 767 if (!(feature & uaf->mask)) 768 continue; 769 770 old_feature = af.features & feature; 771 new_feature = uaf->features & feature; 772 new_lock = (uaf->lock | af.lock) & feature; 773 old_lock = af.lock & feature; 774 775 /* are we changing a locked feature? */ 776 if (old_lock && (new_feature != old_feature)) { 777 audit_log_feature_change(i, old_feature, new_feature, 778 old_lock, new_lock, 0); 779 return -EPERM; 780 } 781 } 782 /* nothing invalid, do the changes */ 783 for (i = 0; i <= AUDIT_LAST_FEATURE; i++) { 784 u32 feature = AUDIT_FEATURE_TO_MASK(i); 785 u32 old_feature, new_feature, old_lock, new_lock; 786 787 /* if we are not changing this feature, move along */ 788 if (!(feature & uaf->mask)) 789 continue; 790 791 old_feature = af.features & feature; 792 new_feature = uaf->features & feature; 793 old_lock = af.lock & feature; 794 new_lock = (uaf->lock | af.lock) & feature; 795 796 if (new_feature != old_feature) 797 audit_log_feature_change(i, old_feature, new_feature, 798 old_lock, new_lock, 1); 799 800 if (new_feature) 801 af.features |= feature; 802 else 803 af.features &= ~feature; 804 af.lock |= new_lock; 805 } 806 807 return 0; 808 } 809 810 static int audit_replace(pid_t pid) 811 { 812 struct sk_buff *skb = audit_make_reply(0, 0, AUDIT_REPLACE, 0, 0, 813 &pid, sizeof(pid)); 814 815 if (!skb) 816 return -ENOMEM; 817 return netlink_unicast(audit_sock, skb, audit_nlk_portid, 0); 818 } 819 820 static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) 821 { 822 u32 seq; 823 void *data; 824 int err; 825 struct audit_buffer *ab; 826 u16 msg_type = nlh->nlmsg_type; 827 struct audit_sig_info *sig_data; 828 char *ctx = NULL; 829 u32 len; 830 831 err = audit_netlink_ok(skb, msg_type); 832 if (err) 833 return err; 834 835 /* As soon as there's any sign of userspace auditd, 836 * start kauditd to talk to it */ 837 if (!kauditd_task) { 838 kauditd_task = kthread_run(kauditd_thread, NULL, "kauditd"); 839 if (IS_ERR(kauditd_task)) { 840 err = PTR_ERR(kauditd_task); 841 kauditd_task = NULL; 842 return err; 843 } 844 } 845 seq = nlh->nlmsg_seq; 846 data = nlmsg_data(nlh); 847 848 switch (msg_type) { 849 case AUDIT_GET: { 850 struct audit_status s; 851 memset(&s, 0, sizeof(s)); 852 s.enabled = audit_enabled; 853 s.failure = audit_failure; 854 s.pid = audit_pid; 855 s.rate_limit = audit_rate_limit; 856 s.backlog_limit = audit_backlog_limit; 857 s.lost = atomic_read(&audit_lost); 858 s.backlog = skb_queue_len(&audit_skb_queue); 859 s.feature_bitmap = AUDIT_FEATURE_BITMAP_ALL; 860 s.backlog_wait_time = audit_backlog_wait_time_master; 861 audit_send_reply(skb, seq, AUDIT_GET, 0, 0, &s, sizeof(s)); 862 break; 863 } 864 case AUDIT_SET: { 865 struct audit_status s; 866 memset(&s, 0, sizeof(s)); 867 /* guard against past and future API changes */ 868 memcpy(&s, data, min_t(size_t, sizeof(s), nlmsg_len(nlh))); 869 if (s.mask & AUDIT_STATUS_ENABLED) { 870 err = audit_set_enabled(s.enabled); 871 if (err < 0) 872 return err; 873 } 874 if (s.mask & AUDIT_STATUS_FAILURE) { 875 err = audit_set_failure(s.failure); 876 if (err < 0) 877 return err; 878 } 879 if (s.mask & AUDIT_STATUS_PID) { 880 /* NOTE: we are using task_tgid_vnr() below because 881 * the s.pid value is relative to the namespace 882 * of the caller; at present this doesn't matter 883 * much since you can really only run auditd 884 * from the initial pid namespace, but something 885 * to keep in mind if this changes */ 886 int new_pid = s.pid; 887 pid_t requesting_pid = task_tgid_vnr(current); 888 889 if ((!new_pid) && (requesting_pid != audit_pid)) { 890 audit_log_config_change("audit_pid", new_pid, audit_pid, 0); 891 return -EACCES; 892 } 893 if (audit_pid && new_pid && 894 audit_replace(requesting_pid) != -ECONNREFUSED) { 895 audit_log_config_change("audit_pid", new_pid, audit_pid, 0); 896 return -EEXIST; 897 } 898 if (audit_enabled != AUDIT_OFF) 899 audit_log_config_change("audit_pid", new_pid, audit_pid, 1); 900 audit_pid = new_pid; 901 audit_nlk_portid = NETLINK_CB(skb).portid; 902 audit_sock = skb->sk; 903 } 904 if (s.mask & AUDIT_STATUS_RATE_LIMIT) { 905 err = audit_set_rate_limit(s.rate_limit); 906 if (err < 0) 907 return err; 908 } 909 if (s.mask & AUDIT_STATUS_BACKLOG_LIMIT) { 910 err = audit_set_backlog_limit(s.backlog_limit); 911 if (err < 0) 912 return err; 913 } 914 if (s.mask & AUDIT_STATUS_BACKLOG_WAIT_TIME) { 915 if (sizeof(s) > (size_t)nlh->nlmsg_len) 916 return -EINVAL; 917 if (s.backlog_wait_time > 10*AUDIT_BACKLOG_WAIT_TIME) 918 return -EINVAL; 919 err = audit_set_backlog_wait_time(s.backlog_wait_time); 920 if (err < 0) 921 return err; 922 } 923 break; 924 } 925 case AUDIT_GET_FEATURE: 926 err = audit_get_feature(skb); 927 if (err) 928 return err; 929 break; 930 case AUDIT_SET_FEATURE: 931 err = audit_set_feature(skb); 932 if (err) 933 return err; 934 break; 935 case AUDIT_USER: 936 case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG: 937 case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2: 938 if (!audit_enabled && msg_type != AUDIT_USER_AVC) 939 return 0; 940 941 err = audit_filter(msg_type, AUDIT_FILTER_USER); 942 if (err == 1) { /* match or error */ 943 err = 0; 944 if (msg_type == AUDIT_USER_TTY) { 945 err = tty_audit_push(); 946 if (err) 947 break; 948 } 949 mutex_unlock(&audit_cmd_mutex); 950 audit_log_common_recv_msg(&ab, msg_type); 951 if (msg_type != AUDIT_USER_TTY) 952 audit_log_format(ab, " msg='%.*s'", 953 AUDIT_MESSAGE_TEXT_MAX, 954 (char *)data); 955 else { 956 int size; 957 958 audit_log_format(ab, " data="); 959 size = nlmsg_len(nlh); 960 if (size > 0 && 961 ((unsigned char *)data)[size - 1] == '\0') 962 size--; 963 audit_log_n_untrustedstring(ab, data, size); 964 } 965 audit_set_portid(ab, NETLINK_CB(skb).portid); 966 audit_log_end(ab); 967 mutex_lock(&audit_cmd_mutex); 968 } 969 break; 970 case AUDIT_ADD_RULE: 971 case AUDIT_DEL_RULE: 972 if (nlmsg_len(nlh) < sizeof(struct audit_rule_data)) 973 return -EINVAL; 974 if (audit_enabled == AUDIT_LOCKED) { 975 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE); 976 audit_log_format(ab, " audit_enabled=%d res=0", audit_enabled); 977 audit_log_end(ab); 978 return -EPERM; 979 } 980 err = audit_rule_change(msg_type, NETLINK_CB(skb).portid, 981 seq, data, nlmsg_len(nlh)); 982 break; 983 case AUDIT_LIST_RULES: 984 err = audit_list_rules_send(skb, seq); 985 break; 986 case AUDIT_TRIM: 987 audit_trim_trees(); 988 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE); 989 audit_log_format(ab, " op=trim res=1"); 990 audit_log_end(ab); 991 break; 992 case AUDIT_MAKE_EQUIV: { 993 void *bufp = data; 994 u32 sizes[2]; 995 size_t msglen = nlmsg_len(nlh); 996 char *old, *new; 997 998 err = -EINVAL; 999 if (msglen < 2 * sizeof(u32)) 1000 break; 1001 memcpy(sizes, bufp, 2 * sizeof(u32)); 1002 bufp += 2 * sizeof(u32); 1003 msglen -= 2 * sizeof(u32); 1004 old = audit_unpack_string(&bufp, &msglen, sizes[0]); 1005 if (IS_ERR(old)) { 1006 err = PTR_ERR(old); 1007 break; 1008 } 1009 new = audit_unpack_string(&bufp, &msglen, sizes[1]); 1010 if (IS_ERR(new)) { 1011 err = PTR_ERR(new); 1012 kfree(old); 1013 break; 1014 } 1015 /* OK, here comes... */ 1016 err = audit_tag_tree(old, new); 1017 1018 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE); 1019 1020 audit_log_format(ab, " op=make_equiv old="); 1021 audit_log_untrustedstring(ab, old); 1022 audit_log_format(ab, " new="); 1023 audit_log_untrustedstring(ab, new); 1024 audit_log_format(ab, " res=%d", !err); 1025 audit_log_end(ab); 1026 kfree(old); 1027 kfree(new); 1028 break; 1029 } 1030 case AUDIT_SIGNAL_INFO: 1031 len = 0; 1032 if (audit_sig_sid) { 1033 err = security_secid_to_secctx(audit_sig_sid, &ctx, &len); 1034 if (err) 1035 return err; 1036 } 1037 sig_data = kmalloc(sizeof(*sig_data) + len, GFP_KERNEL); 1038 if (!sig_data) { 1039 if (audit_sig_sid) 1040 security_release_secctx(ctx, len); 1041 return -ENOMEM; 1042 } 1043 sig_data->uid = from_kuid(&init_user_ns, audit_sig_uid); 1044 sig_data->pid = audit_sig_pid; 1045 if (audit_sig_sid) { 1046 memcpy(sig_data->ctx, ctx, len); 1047 security_release_secctx(ctx, len); 1048 } 1049 audit_send_reply(skb, seq, AUDIT_SIGNAL_INFO, 0, 0, 1050 sig_data, sizeof(*sig_data) + len); 1051 kfree(sig_data); 1052 break; 1053 case AUDIT_TTY_GET: { 1054 struct audit_tty_status s; 1055 unsigned int t; 1056 1057 t = READ_ONCE(current->signal->audit_tty); 1058 s.enabled = t & AUDIT_TTY_ENABLE; 1059 s.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD); 1060 1061 audit_send_reply(skb, seq, AUDIT_TTY_GET, 0, 0, &s, sizeof(s)); 1062 break; 1063 } 1064 case AUDIT_TTY_SET: { 1065 struct audit_tty_status s, old; 1066 struct audit_buffer *ab; 1067 unsigned int t; 1068 1069 memset(&s, 0, sizeof(s)); 1070 /* guard against past and future API changes */ 1071 memcpy(&s, data, min_t(size_t, sizeof(s), nlmsg_len(nlh))); 1072 /* check if new data is valid */ 1073 if ((s.enabled != 0 && s.enabled != 1) || 1074 (s.log_passwd != 0 && s.log_passwd != 1)) 1075 err = -EINVAL; 1076 1077 if (err) 1078 t = READ_ONCE(current->signal->audit_tty); 1079 else { 1080 t = s.enabled | (-s.log_passwd & AUDIT_TTY_LOG_PASSWD); 1081 t = xchg(¤t->signal->audit_tty, t); 1082 } 1083 old.enabled = t & AUDIT_TTY_ENABLE; 1084 old.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD); 1085 1086 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE); 1087 audit_log_format(ab, " op=tty_set old-enabled=%d new-enabled=%d" 1088 " old-log_passwd=%d new-log_passwd=%d res=%d", 1089 old.enabled, s.enabled, old.log_passwd, 1090 s.log_passwd, !err); 1091 audit_log_end(ab); 1092 break; 1093 } 1094 default: 1095 err = -EINVAL; 1096 break; 1097 } 1098 1099 return err < 0 ? err : 0; 1100 } 1101 1102 /* 1103 * Get message from skb. Each message is processed by audit_receive_msg. 1104 * Malformed skbs with wrong length are discarded silently. 1105 */ 1106 static void audit_receive_skb(struct sk_buff *skb) 1107 { 1108 struct nlmsghdr *nlh; 1109 /* 1110 * len MUST be signed for nlmsg_next to be able to dec it below 0 1111 * if the nlmsg_len was not aligned 1112 */ 1113 int len; 1114 int err; 1115 1116 nlh = nlmsg_hdr(skb); 1117 len = skb->len; 1118 1119 while (nlmsg_ok(nlh, len)) { 1120 err = audit_receive_msg(skb, nlh); 1121 /* if err or if this message says it wants a response */ 1122 if (err || (nlh->nlmsg_flags & NLM_F_ACK)) 1123 netlink_ack(skb, nlh, err); 1124 1125 nlh = nlmsg_next(nlh, &len); 1126 } 1127 } 1128 1129 /* Receive messages from netlink socket. */ 1130 static void audit_receive(struct sk_buff *skb) 1131 { 1132 mutex_lock(&audit_cmd_mutex); 1133 audit_receive_skb(skb); 1134 mutex_unlock(&audit_cmd_mutex); 1135 } 1136 1137 /* Run custom bind function on netlink socket group connect or bind requests. */ 1138 static int audit_bind(struct net *net, int group) 1139 { 1140 if (!capable(CAP_AUDIT_READ)) 1141 return -EPERM; 1142 1143 return 0; 1144 } 1145 1146 static int __net_init audit_net_init(struct net *net) 1147 { 1148 struct netlink_kernel_cfg cfg = { 1149 .input = audit_receive, 1150 .bind = audit_bind, 1151 .flags = NL_CFG_F_NONROOT_RECV, 1152 .groups = AUDIT_NLGRP_MAX, 1153 }; 1154 1155 struct audit_net *aunet = net_generic(net, audit_net_id); 1156 1157 aunet->nlsk = netlink_kernel_create(net, NETLINK_AUDIT, &cfg); 1158 if (aunet->nlsk == NULL) { 1159 audit_panic("cannot initialize netlink socket in namespace"); 1160 return -ENOMEM; 1161 } 1162 aunet->nlsk->sk_sndtimeo = MAX_SCHEDULE_TIMEOUT; 1163 return 0; 1164 } 1165 1166 static void __net_exit audit_net_exit(struct net *net) 1167 { 1168 struct audit_net *aunet = net_generic(net, audit_net_id); 1169 struct sock *sock = aunet->nlsk; 1170 if (sock == audit_sock) { 1171 audit_pid = 0; 1172 audit_sock = NULL; 1173 } 1174 1175 RCU_INIT_POINTER(aunet->nlsk, NULL); 1176 synchronize_net(); 1177 netlink_kernel_release(sock); 1178 } 1179 1180 static struct pernet_operations audit_net_ops __net_initdata = { 1181 .init = audit_net_init, 1182 .exit = audit_net_exit, 1183 .id = &audit_net_id, 1184 .size = sizeof(struct audit_net), 1185 }; 1186 1187 /* Initialize audit support at boot time. */ 1188 static int __init audit_init(void) 1189 { 1190 int i; 1191 1192 if (audit_initialized == AUDIT_DISABLED) 1193 return 0; 1194 1195 pr_info("initializing netlink subsys (%s)\n", 1196 audit_default ? "enabled" : "disabled"); 1197 register_pernet_subsys(&audit_net_ops); 1198 1199 skb_queue_head_init(&audit_skb_queue); 1200 skb_queue_head_init(&audit_skb_hold_queue); 1201 audit_initialized = AUDIT_INITIALIZED; 1202 audit_enabled = audit_default; 1203 audit_ever_enabled |= !!audit_default; 1204 1205 audit_log(NULL, GFP_KERNEL, AUDIT_KERNEL, "initialized"); 1206 1207 for (i = 0; i < AUDIT_INODE_BUCKETS; i++) 1208 INIT_LIST_HEAD(&audit_inode_hash[i]); 1209 1210 return 0; 1211 } 1212 __initcall(audit_init); 1213 1214 /* Process kernel command-line parameter at boot time. audit=0 or audit=1. */ 1215 static int __init audit_enable(char *str) 1216 { 1217 audit_default = !!simple_strtol(str, NULL, 0); 1218 if (!audit_default) 1219 audit_initialized = AUDIT_DISABLED; 1220 1221 pr_info("%s\n", audit_default ? 1222 "enabled (after initialization)" : "disabled (until reboot)"); 1223 1224 return 1; 1225 } 1226 __setup("audit=", audit_enable); 1227 1228 /* Process kernel command-line parameter at boot time. 1229 * audit_backlog_limit=<n> */ 1230 static int __init audit_backlog_limit_set(char *str) 1231 { 1232 u32 audit_backlog_limit_arg; 1233 1234 pr_info("audit_backlog_limit: "); 1235 if (kstrtouint(str, 0, &audit_backlog_limit_arg)) { 1236 pr_cont("using default of %u, unable to parse %s\n", 1237 audit_backlog_limit, str); 1238 return 1; 1239 } 1240 1241 audit_backlog_limit = audit_backlog_limit_arg; 1242 pr_cont("%d\n", audit_backlog_limit); 1243 1244 return 1; 1245 } 1246 __setup("audit_backlog_limit=", audit_backlog_limit_set); 1247 1248 static void audit_buffer_free(struct audit_buffer *ab) 1249 { 1250 unsigned long flags; 1251 1252 if (!ab) 1253 return; 1254 1255 kfree_skb(ab->skb); 1256 spin_lock_irqsave(&audit_freelist_lock, flags); 1257 if (audit_freelist_count > AUDIT_MAXFREE) 1258 kfree(ab); 1259 else { 1260 audit_freelist_count++; 1261 list_add(&ab->list, &audit_freelist); 1262 } 1263 spin_unlock_irqrestore(&audit_freelist_lock, flags); 1264 } 1265 1266 static struct audit_buffer * audit_buffer_alloc(struct audit_context *ctx, 1267 gfp_t gfp_mask, int type) 1268 { 1269 unsigned long flags; 1270 struct audit_buffer *ab = NULL; 1271 struct nlmsghdr *nlh; 1272 1273 spin_lock_irqsave(&audit_freelist_lock, flags); 1274 if (!list_empty(&audit_freelist)) { 1275 ab = list_entry(audit_freelist.next, 1276 struct audit_buffer, list); 1277 list_del(&ab->list); 1278 --audit_freelist_count; 1279 } 1280 spin_unlock_irqrestore(&audit_freelist_lock, flags); 1281 1282 if (!ab) { 1283 ab = kmalloc(sizeof(*ab), gfp_mask); 1284 if (!ab) 1285 goto err; 1286 } 1287 1288 ab->ctx = ctx; 1289 ab->gfp_mask = gfp_mask; 1290 1291 ab->skb = nlmsg_new(AUDIT_BUFSIZ, gfp_mask); 1292 if (!ab->skb) 1293 goto err; 1294 1295 nlh = nlmsg_put(ab->skb, 0, 0, type, 0, 0); 1296 if (!nlh) 1297 goto out_kfree_skb; 1298 1299 return ab; 1300 1301 out_kfree_skb: 1302 kfree_skb(ab->skb); 1303 ab->skb = NULL; 1304 err: 1305 audit_buffer_free(ab); 1306 return NULL; 1307 } 1308 1309 /** 1310 * audit_serial - compute a serial number for the audit record 1311 * 1312 * Compute a serial number for the audit record. Audit records are 1313 * written to user-space as soon as they are generated, so a complete 1314 * audit record may be written in several pieces. The timestamp of the 1315 * record and this serial number are used by the user-space tools to 1316 * determine which pieces belong to the same audit record. The 1317 * (timestamp,serial) tuple is unique for each syscall and is live from 1318 * syscall entry to syscall exit. 1319 * 1320 * NOTE: Another possibility is to store the formatted records off the 1321 * audit context (for those records that have a context), and emit them 1322 * all at syscall exit. However, this could delay the reporting of 1323 * significant errors until syscall exit (or never, if the system 1324 * halts). 1325 */ 1326 unsigned int audit_serial(void) 1327 { 1328 static atomic_t serial = ATOMIC_INIT(0); 1329 1330 return atomic_add_return(1, &serial); 1331 } 1332 1333 static inline void audit_get_stamp(struct audit_context *ctx, 1334 struct timespec *t, unsigned int *serial) 1335 { 1336 if (!ctx || !auditsc_get_stamp(ctx, t, serial)) { 1337 *t = CURRENT_TIME; 1338 *serial = audit_serial(); 1339 } 1340 } 1341 1342 /* 1343 * Wait for auditd to drain the queue a little 1344 */ 1345 static long wait_for_auditd(long sleep_time) 1346 { 1347 DECLARE_WAITQUEUE(wait, current); 1348 1349 if (audit_backlog_limit && 1350 skb_queue_len(&audit_skb_queue) > audit_backlog_limit) { 1351 add_wait_queue_exclusive(&audit_backlog_wait, &wait); 1352 set_current_state(TASK_UNINTERRUPTIBLE); 1353 sleep_time = schedule_timeout(sleep_time); 1354 remove_wait_queue(&audit_backlog_wait, &wait); 1355 } 1356 1357 return sleep_time; 1358 } 1359 1360 /** 1361 * audit_log_start - obtain an audit buffer 1362 * @ctx: audit_context (may be NULL) 1363 * @gfp_mask: type of allocation 1364 * @type: audit message type 1365 * 1366 * Returns audit_buffer pointer on success or NULL on error. 1367 * 1368 * Obtain an audit buffer. This routine does locking to obtain the 1369 * audit buffer, but then no locking is required for calls to 1370 * audit_log_*format. If the task (ctx) is a task that is currently in a 1371 * syscall, then the syscall is marked as auditable and an audit record 1372 * will be written at syscall exit. If there is no associated task, then 1373 * task context (ctx) should be NULL. 1374 */ 1375 struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask, 1376 int type) 1377 { 1378 struct audit_buffer *ab = NULL; 1379 struct timespec t; 1380 unsigned int uninitialized_var(serial); 1381 int reserve = 5; /* Allow atomic callers to go up to five 1382 entries over the normal backlog limit */ 1383 unsigned long timeout_start = jiffies; 1384 1385 if (audit_initialized != AUDIT_INITIALIZED) 1386 return NULL; 1387 1388 if (unlikely(!audit_filter(type, AUDIT_FILTER_TYPE))) 1389 return NULL; 1390 1391 if (gfp_mask & __GFP_DIRECT_RECLAIM) { 1392 if (audit_pid && audit_pid == current->tgid) 1393 gfp_mask &= ~__GFP_DIRECT_RECLAIM; 1394 else 1395 reserve = 0; 1396 } 1397 1398 while (audit_backlog_limit 1399 && skb_queue_len(&audit_skb_queue) > audit_backlog_limit + reserve) { 1400 if (gfp_mask & __GFP_DIRECT_RECLAIM && audit_backlog_wait_time) { 1401 long sleep_time; 1402 1403 sleep_time = timeout_start + audit_backlog_wait_time - jiffies; 1404 if (sleep_time > 0) { 1405 sleep_time = wait_for_auditd(sleep_time); 1406 if (sleep_time > 0) 1407 continue; 1408 } 1409 } 1410 if (audit_rate_check() && printk_ratelimit()) 1411 pr_warn("audit_backlog=%d > audit_backlog_limit=%d\n", 1412 skb_queue_len(&audit_skb_queue), 1413 audit_backlog_limit); 1414 audit_log_lost("backlog limit exceeded"); 1415 audit_backlog_wait_time = 0; 1416 wake_up(&audit_backlog_wait); 1417 return NULL; 1418 } 1419 1420 if (!reserve && !audit_backlog_wait_time) 1421 audit_backlog_wait_time = audit_backlog_wait_time_master; 1422 1423 ab = audit_buffer_alloc(ctx, gfp_mask, type); 1424 if (!ab) { 1425 audit_log_lost("out of memory in audit_log_start"); 1426 return NULL; 1427 } 1428 1429 audit_get_stamp(ab->ctx, &t, &serial); 1430 1431 audit_log_format(ab, "audit(%lu.%03lu:%u): ", 1432 t.tv_sec, t.tv_nsec/1000000, serial); 1433 return ab; 1434 } 1435 1436 /** 1437 * audit_expand - expand skb in the audit buffer 1438 * @ab: audit_buffer 1439 * @extra: space to add at tail of the skb 1440 * 1441 * Returns 0 (no space) on failed expansion, or available space if 1442 * successful. 1443 */ 1444 static inline int audit_expand(struct audit_buffer *ab, int extra) 1445 { 1446 struct sk_buff *skb = ab->skb; 1447 int oldtail = skb_tailroom(skb); 1448 int ret = pskb_expand_head(skb, 0, extra, ab->gfp_mask); 1449 int newtail = skb_tailroom(skb); 1450 1451 if (ret < 0) { 1452 audit_log_lost("out of memory in audit_expand"); 1453 return 0; 1454 } 1455 1456 skb->truesize += newtail - oldtail; 1457 return newtail; 1458 } 1459 1460 /* 1461 * Format an audit message into the audit buffer. If there isn't enough 1462 * room in the audit buffer, more room will be allocated and vsnprint 1463 * will be called a second time. Currently, we assume that a printk 1464 * can't format message larger than 1024 bytes, so we don't either. 1465 */ 1466 static void audit_log_vformat(struct audit_buffer *ab, const char *fmt, 1467 va_list args) 1468 { 1469 int len, avail; 1470 struct sk_buff *skb; 1471 va_list args2; 1472 1473 if (!ab) 1474 return; 1475 1476 BUG_ON(!ab->skb); 1477 skb = ab->skb; 1478 avail = skb_tailroom(skb); 1479 if (avail == 0) { 1480 avail = audit_expand(ab, AUDIT_BUFSIZ); 1481 if (!avail) 1482 goto out; 1483 } 1484 va_copy(args2, args); 1485 len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args); 1486 if (len >= avail) { 1487 /* The printk buffer is 1024 bytes long, so if we get 1488 * here and AUDIT_BUFSIZ is at least 1024, then we can 1489 * log everything that printk could have logged. */ 1490 avail = audit_expand(ab, 1491 max_t(unsigned, AUDIT_BUFSIZ, 1+len-avail)); 1492 if (!avail) 1493 goto out_va_end; 1494 len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args2); 1495 } 1496 if (len > 0) 1497 skb_put(skb, len); 1498 out_va_end: 1499 va_end(args2); 1500 out: 1501 return; 1502 } 1503 1504 /** 1505 * audit_log_format - format a message into the audit buffer. 1506 * @ab: audit_buffer 1507 * @fmt: format string 1508 * @...: optional parameters matching @fmt string 1509 * 1510 * All the work is done in audit_log_vformat. 1511 */ 1512 void audit_log_format(struct audit_buffer *ab, const char *fmt, ...) 1513 { 1514 va_list args; 1515 1516 if (!ab) 1517 return; 1518 va_start(args, fmt); 1519 audit_log_vformat(ab, fmt, args); 1520 va_end(args); 1521 } 1522 1523 /** 1524 * audit_log_hex - convert a buffer to hex and append it to the audit skb 1525 * @ab: the audit_buffer 1526 * @buf: buffer to convert to hex 1527 * @len: length of @buf to be converted 1528 * 1529 * No return value; failure to expand is silently ignored. 1530 * 1531 * This function will take the passed buf and convert it into a string of 1532 * ascii hex digits. The new string is placed onto the skb. 1533 */ 1534 void audit_log_n_hex(struct audit_buffer *ab, const unsigned char *buf, 1535 size_t len) 1536 { 1537 int i, avail, new_len; 1538 unsigned char *ptr; 1539 struct sk_buff *skb; 1540 1541 if (!ab) 1542 return; 1543 1544 BUG_ON(!ab->skb); 1545 skb = ab->skb; 1546 avail = skb_tailroom(skb); 1547 new_len = len<<1; 1548 if (new_len >= avail) { 1549 /* Round the buffer request up to the next multiple */ 1550 new_len = AUDIT_BUFSIZ*(((new_len-avail)/AUDIT_BUFSIZ) + 1); 1551 avail = audit_expand(ab, new_len); 1552 if (!avail) 1553 return; 1554 } 1555 1556 ptr = skb_tail_pointer(skb); 1557 for (i = 0; i < len; i++) 1558 ptr = hex_byte_pack_upper(ptr, buf[i]); 1559 *ptr = 0; 1560 skb_put(skb, len << 1); /* new string is twice the old string */ 1561 } 1562 1563 /* 1564 * Format a string of no more than slen characters into the audit buffer, 1565 * enclosed in quote marks. 1566 */ 1567 void audit_log_n_string(struct audit_buffer *ab, const char *string, 1568 size_t slen) 1569 { 1570 int avail, new_len; 1571 unsigned char *ptr; 1572 struct sk_buff *skb; 1573 1574 if (!ab) 1575 return; 1576 1577 BUG_ON(!ab->skb); 1578 skb = ab->skb; 1579 avail = skb_tailroom(skb); 1580 new_len = slen + 3; /* enclosing quotes + null terminator */ 1581 if (new_len > avail) { 1582 avail = audit_expand(ab, new_len); 1583 if (!avail) 1584 return; 1585 } 1586 ptr = skb_tail_pointer(skb); 1587 *ptr++ = '"'; 1588 memcpy(ptr, string, slen); 1589 ptr += slen; 1590 *ptr++ = '"'; 1591 *ptr = 0; 1592 skb_put(skb, slen + 2); /* don't include null terminator */ 1593 } 1594 1595 /** 1596 * audit_string_contains_control - does a string need to be logged in hex 1597 * @string: string to be checked 1598 * @len: max length of the string to check 1599 */ 1600 bool audit_string_contains_control(const char *string, size_t len) 1601 { 1602 const unsigned char *p; 1603 for (p = string; p < (const unsigned char *)string + len; p++) { 1604 if (*p == '"' || *p < 0x21 || *p > 0x7e) 1605 return true; 1606 } 1607 return false; 1608 } 1609 1610 /** 1611 * audit_log_n_untrustedstring - log a string that may contain random characters 1612 * @ab: audit_buffer 1613 * @len: length of string (not including trailing null) 1614 * @string: string to be logged 1615 * 1616 * This code will escape a string that is passed to it if the string 1617 * contains a control character, unprintable character, double quote mark, 1618 * or a space. Unescaped strings will start and end with a double quote mark. 1619 * Strings that are escaped are printed in hex (2 digits per char). 1620 * 1621 * The caller specifies the number of characters in the string to log, which may 1622 * or may not be the entire string. 1623 */ 1624 void audit_log_n_untrustedstring(struct audit_buffer *ab, const char *string, 1625 size_t len) 1626 { 1627 if (audit_string_contains_control(string, len)) 1628 audit_log_n_hex(ab, string, len); 1629 else 1630 audit_log_n_string(ab, string, len); 1631 } 1632 1633 /** 1634 * audit_log_untrustedstring - log a string that may contain random characters 1635 * @ab: audit_buffer 1636 * @string: string to be logged 1637 * 1638 * Same as audit_log_n_untrustedstring(), except that strlen is used to 1639 * determine string length. 1640 */ 1641 void audit_log_untrustedstring(struct audit_buffer *ab, const char *string) 1642 { 1643 audit_log_n_untrustedstring(ab, string, strlen(string)); 1644 } 1645 1646 /* This is a helper-function to print the escaped d_path */ 1647 void audit_log_d_path(struct audit_buffer *ab, const char *prefix, 1648 const struct path *path) 1649 { 1650 char *p, *pathname; 1651 1652 if (prefix) 1653 audit_log_format(ab, "%s", prefix); 1654 1655 /* We will allow 11 spaces for ' (deleted)' to be appended */ 1656 pathname = kmalloc(PATH_MAX+11, ab->gfp_mask); 1657 if (!pathname) { 1658 audit_log_string(ab, "<no_memory>"); 1659 return; 1660 } 1661 p = d_path(path, pathname, PATH_MAX+11); 1662 if (IS_ERR(p)) { /* Should never happen since we send PATH_MAX */ 1663 /* FIXME: can we save some information here? */ 1664 audit_log_string(ab, "<too_long>"); 1665 } else 1666 audit_log_untrustedstring(ab, p); 1667 kfree(pathname); 1668 } 1669 1670 void audit_log_session_info(struct audit_buffer *ab) 1671 { 1672 unsigned int sessionid = audit_get_sessionid(current); 1673 uid_t auid = from_kuid(&init_user_ns, audit_get_loginuid(current)); 1674 1675 audit_log_format(ab, " auid=%u ses=%u", auid, sessionid); 1676 } 1677 1678 void audit_log_key(struct audit_buffer *ab, char *key) 1679 { 1680 audit_log_format(ab, " key="); 1681 if (key) 1682 audit_log_untrustedstring(ab, key); 1683 else 1684 audit_log_format(ab, "(null)"); 1685 } 1686 1687 void audit_log_cap(struct audit_buffer *ab, char *prefix, kernel_cap_t *cap) 1688 { 1689 int i; 1690 1691 audit_log_format(ab, " %s=", prefix); 1692 CAP_FOR_EACH_U32(i) { 1693 audit_log_format(ab, "%08x", 1694 cap->cap[CAP_LAST_U32 - i]); 1695 } 1696 } 1697 1698 static void audit_log_fcaps(struct audit_buffer *ab, struct audit_names *name) 1699 { 1700 kernel_cap_t *perm = &name->fcap.permitted; 1701 kernel_cap_t *inh = &name->fcap.inheritable; 1702 int log = 0; 1703 1704 if (!cap_isclear(*perm)) { 1705 audit_log_cap(ab, "cap_fp", perm); 1706 log = 1; 1707 } 1708 if (!cap_isclear(*inh)) { 1709 audit_log_cap(ab, "cap_fi", inh); 1710 log = 1; 1711 } 1712 1713 if (log) 1714 audit_log_format(ab, " cap_fe=%d cap_fver=%x", 1715 name->fcap.fE, name->fcap_ver); 1716 } 1717 1718 static inline int audit_copy_fcaps(struct audit_names *name, 1719 const struct dentry *dentry) 1720 { 1721 struct cpu_vfs_cap_data caps; 1722 int rc; 1723 1724 if (!dentry) 1725 return 0; 1726 1727 rc = get_vfs_caps_from_disk(dentry, &caps); 1728 if (rc) 1729 return rc; 1730 1731 name->fcap.permitted = caps.permitted; 1732 name->fcap.inheritable = caps.inheritable; 1733 name->fcap.fE = !!(caps.magic_etc & VFS_CAP_FLAGS_EFFECTIVE); 1734 name->fcap_ver = (caps.magic_etc & VFS_CAP_REVISION_MASK) >> 1735 VFS_CAP_REVISION_SHIFT; 1736 1737 return 0; 1738 } 1739 1740 /* Copy inode data into an audit_names. */ 1741 void audit_copy_inode(struct audit_names *name, const struct dentry *dentry, 1742 struct inode *inode) 1743 { 1744 name->ino = inode->i_ino; 1745 name->dev = inode->i_sb->s_dev; 1746 name->mode = inode->i_mode; 1747 name->uid = inode->i_uid; 1748 name->gid = inode->i_gid; 1749 name->rdev = inode->i_rdev; 1750 security_inode_getsecid(inode, &name->osid); 1751 audit_copy_fcaps(name, dentry); 1752 } 1753 1754 /** 1755 * audit_log_name - produce AUDIT_PATH record from struct audit_names 1756 * @context: audit_context for the task 1757 * @n: audit_names structure with reportable details 1758 * @path: optional path to report instead of audit_names->name 1759 * @record_num: record number to report when handling a list of names 1760 * @call_panic: optional pointer to int that will be updated if secid fails 1761 */ 1762 void audit_log_name(struct audit_context *context, struct audit_names *n, 1763 struct path *path, int record_num, int *call_panic) 1764 { 1765 struct audit_buffer *ab; 1766 ab = audit_log_start(context, GFP_KERNEL, AUDIT_PATH); 1767 if (!ab) 1768 return; 1769 1770 audit_log_format(ab, "item=%d", record_num); 1771 1772 if (path) 1773 audit_log_d_path(ab, " name=", path); 1774 else if (n->name) { 1775 switch (n->name_len) { 1776 case AUDIT_NAME_FULL: 1777 /* log the full path */ 1778 audit_log_format(ab, " name="); 1779 audit_log_untrustedstring(ab, n->name->name); 1780 break; 1781 case 0: 1782 /* name was specified as a relative path and the 1783 * directory component is the cwd */ 1784 audit_log_d_path(ab, " name=", &context->pwd); 1785 break; 1786 default: 1787 /* log the name's directory component */ 1788 audit_log_format(ab, " name="); 1789 audit_log_n_untrustedstring(ab, n->name->name, 1790 n->name_len); 1791 } 1792 } else 1793 audit_log_format(ab, " name=(null)"); 1794 1795 if (n->ino != AUDIT_INO_UNSET) 1796 audit_log_format(ab, " inode=%lu" 1797 " dev=%02x:%02x mode=%#ho" 1798 " ouid=%u ogid=%u rdev=%02x:%02x", 1799 n->ino, 1800 MAJOR(n->dev), 1801 MINOR(n->dev), 1802 n->mode, 1803 from_kuid(&init_user_ns, n->uid), 1804 from_kgid(&init_user_ns, n->gid), 1805 MAJOR(n->rdev), 1806 MINOR(n->rdev)); 1807 if (n->osid != 0) { 1808 char *ctx = NULL; 1809 u32 len; 1810 if (security_secid_to_secctx( 1811 n->osid, &ctx, &len)) { 1812 audit_log_format(ab, " osid=%u", n->osid); 1813 if (call_panic) 1814 *call_panic = 2; 1815 } else { 1816 audit_log_format(ab, " obj=%s", ctx); 1817 security_release_secctx(ctx, len); 1818 } 1819 } 1820 1821 /* log the audit_names record type */ 1822 audit_log_format(ab, " nametype="); 1823 switch(n->type) { 1824 case AUDIT_TYPE_NORMAL: 1825 audit_log_format(ab, "NORMAL"); 1826 break; 1827 case AUDIT_TYPE_PARENT: 1828 audit_log_format(ab, "PARENT"); 1829 break; 1830 case AUDIT_TYPE_CHILD_DELETE: 1831 audit_log_format(ab, "DELETE"); 1832 break; 1833 case AUDIT_TYPE_CHILD_CREATE: 1834 audit_log_format(ab, "CREATE"); 1835 break; 1836 default: 1837 audit_log_format(ab, "UNKNOWN"); 1838 break; 1839 } 1840 1841 audit_log_fcaps(ab, n); 1842 audit_log_end(ab); 1843 } 1844 1845 int audit_log_task_context(struct audit_buffer *ab) 1846 { 1847 char *ctx = NULL; 1848 unsigned len; 1849 int error; 1850 u32 sid; 1851 1852 security_task_getsecid(current, &sid); 1853 if (!sid) 1854 return 0; 1855 1856 error = security_secid_to_secctx(sid, &ctx, &len); 1857 if (error) { 1858 if (error != -EINVAL) 1859 goto error_path; 1860 return 0; 1861 } 1862 1863 audit_log_format(ab, " subj=%s", ctx); 1864 security_release_secctx(ctx, len); 1865 return 0; 1866 1867 error_path: 1868 audit_panic("error in audit_log_task_context"); 1869 return error; 1870 } 1871 EXPORT_SYMBOL(audit_log_task_context); 1872 1873 void audit_log_d_path_exe(struct audit_buffer *ab, 1874 struct mm_struct *mm) 1875 { 1876 struct file *exe_file; 1877 1878 if (!mm) 1879 goto out_null; 1880 1881 exe_file = get_mm_exe_file(mm); 1882 if (!exe_file) 1883 goto out_null; 1884 1885 audit_log_d_path(ab, " exe=", &exe_file->f_path); 1886 fput(exe_file); 1887 return; 1888 out_null: 1889 audit_log_format(ab, " exe=(null)"); 1890 } 1891 1892 struct tty_struct *audit_get_tty(struct task_struct *tsk) 1893 { 1894 struct tty_struct *tty = NULL; 1895 unsigned long flags; 1896 1897 spin_lock_irqsave(&tsk->sighand->siglock, flags); 1898 if (tsk->signal) 1899 tty = tty_kref_get(tsk->signal->tty); 1900 spin_unlock_irqrestore(&tsk->sighand->siglock, flags); 1901 return tty; 1902 } 1903 1904 void audit_put_tty(struct tty_struct *tty) 1905 { 1906 tty_kref_put(tty); 1907 } 1908 1909 void audit_log_task_info(struct audit_buffer *ab, struct task_struct *tsk) 1910 { 1911 const struct cred *cred; 1912 char comm[sizeof(tsk->comm)]; 1913 struct tty_struct *tty; 1914 1915 if (!ab) 1916 return; 1917 1918 /* tsk == current */ 1919 cred = current_cred(); 1920 tty = audit_get_tty(tsk); 1921 audit_log_format(ab, 1922 " ppid=%d pid=%d auid=%u uid=%u gid=%u" 1923 " euid=%u suid=%u fsuid=%u" 1924 " egid=%u sgid=%u fsgid=%u tty=%s ses=%u", 1925 task_ppid_nr(tsk), 1926 task_tgid_nr(tsk), 1927 from_kuid(&init_user_ns, audit_get_loginuid(tsk)), 1928 from_kuid(&init_user_ns, cred->uid), 1929 from_kgid(&init_user_ns, cred->gid), 1930 from_kuid(&init_user_ns, cred->euid), 1931 from_kuid(&init_user_ns, cred->suid), 1932 from_kuid(&init_user_ns, cred->fsuid), 1933 from_kgid(&init_user_ns, cred->egid), 1934 from_kgid(&init_user_ns, cred->sgid), 1935 from_kgid(&init_user_ns, cred->fsgid), 1936 tty ? tty_name(tty) : "(none)", 1937 audit_get_sessionid(tsk)); 1938 audit_put_tty(tty); 1939 audit_log_format(ab, " comm="); 1940 audit_log_untrustedstring(ab, get_task_comm(comm, tsk)); 1941 audit_log_d_path_exe(ab, tsk->mm); 1942 audit_log_task_context(ab); 1943 } 1944 EXPORT_SYMBOL(audit_log_task_info); 1945 1946 /** 1947 * audit_log_link_denied - report a link restriction denial 1948 * @operation: specific link operation 1949 * @link: the path that triggered the restriction 1950 */ 1951 void audit_log_link_denied(const char *operation, struct path *link) 1952 { 1953 struct audit_buffer *ab; 1954 struct audit_names *name; 1955 1956 name = kzalloc(sizeof(*name), GFP_NOFS); 1957 if (!name) 1958 return; 1959 1960 /* Generate AUDIT_ANOM_LINK with subject, operation, outcome. */ 1961 ab = audit_log_start(current->audit_context, GFP_KERNEL, 1962 AUDIT_ANOM_LINK); 1963 if (!ab) 1964 goto out; 1965 audit_log_format(ab, "op=%s", operation); 1966 audit_log_task_info(ab, current); 1967 audit_log_format(ab, " res=0"); 1968 audit_log_end(ab); 1969 1970 /* Generate AUDIT_PATH record with object. */ 1971 name->type = AUDIT_TYPE_NORMAL; 1972 audit_copy_inode(name, link->dentry, d_backing_inode(link->dentry)); 1973 audit_log_name(current->audit_context, name, link, 0, NULL); 1974 out: 1975 kfree(name); 1976 } 1977 1978 /** 1979 * audit_log_end - end one audit record 1980 * @ab: the audit_buffer 1981 * 1982 * netlink_unicast() cannot be called inside an irq context because it blocks 1983 * (last arg, flags, is not set to MSG_DONTWAIT), so the audit buffer is placed 1984 * on a queue and a tasklet is scheduled to remove them from the queue outside 1985 * the irq context. May be called in any context. 1986 */ 1987 void audit_log_end(struct audit_buffer *ab) 1988 { 1989 if (!ab) 1990 return; 1991 if (!audit_rate_check()) { 1992 audit_log_lost("rate limit exceeded"); 1993 } else { 1994 struct nlmsghdr *nlh = nlmsg_hdr(ab->skb); 1995 1996 nlh->nlmsg_len = ab->skb->len; 1997 kauditd_send_multicast_skb(ab->skb, ab->gfp_mask); 1998 1999 /* 2000 * The original kaudit unicast socket sends up messages with 2001 * nlmsg_len set to the payload length rather than the entire 2002 * message length. This breaks the standard set by netlink. 2003 * The existing auditd daemon assumes this breakage. Fixing 2004 * this would require co-ordinating a change in the established 2005 * protocol between the kaudit kernel subsystem and the auditd 2006 * userspace code. 2007 */ 2008 nlh->nlmsg_len -= NLMSG_HDRLEN; 2009 2010 if (audit_pid) { 2011 skb_queue_tail(&audit_skb_queue, ab->skb); 2012 wake_up_interruptible(&kauditd_wait); 2013 } else { 2014 audit_printk_skb(ab->skb); 2015 } 2016 ab->skb = NULL; 2017 } 2018 audit_buffer_free(ab); 2019 } 2020 2021 /** 2022 * audit_log - Log an audit record 2023 * @ctx: audit context 2024 * @gfp_mask: type of allocation 2025 * @type: audit message type 2026 * @fmt: format string to use 2027 * @...: variable parameters matching the format string 2028 * 2029 * This is a convenience function that calls audit_log_start, 2030 * audit_log_vformat, and audit_log_end. It may be called 2031 * in any context. 2032 */ 2033 void audit_log(struct audit_context *ctx, gfp_t gfp_mask, int type, 2034 const char *fmt, ...) 2035 { 2036 struct audit_buffer *ab; 2037 va_list args; 2038 2039 ab = audit_log_start(ctx, gfp_mask, type); 2040 if (ab) { 2041 va_start(args, fmt); 2042 audit_log_vformat(ab, fmt, args); 2043 va_end(args); 2044 audit_log_end(ab); 2045 } 2046 } 2047 2048 #ifdef CONFIG_SECURITY 2049 /** 2050 * audit_log_secctx - Converts and logs SELinux context 2051 * @ab: audit_buffer 2052 * @secid: security number 2053 * 2054 * This is a helper function that calls security_secid_to_secctx to convert 2055 * secid to secctx and then adds the (converted) SELinux context to the audit 2056 * log by calling audit_log_format, thus also preventing leak of internal secid 2057 * to userspace. If secid cannot be converted audit_panic is called. 2058 */ 2059 void audit_log_secctx(struct audit_buffer *ab, u32 secid) 2060 { 2061 u32 len; 2062 char *secctx; 2063 2064 if (security_secid_to_secctx(secid, &secctx, &len)) { 2065 audit_panic("Cannot convert secid to context"); 2066 } else { 2067 audit_log_format(ab, " obj=%s", secctx); 2068 security_release_secctx(secctx, len); 2069 } 2070 } 2071 EXPORT_SYMBOL(audit_log_secctx); 2072 #endif 2073 2074 EXPORT_SYMBOL(audit_log_start); 2075 EXPORT_SYMBOL(audit_log_end); 2076 EXPORT_SYMBOL(audit_log_format); 2077 EXPORT_SYMBOL(audit_log); 2078