1 /* audit.c -- Auditing support 2 * Gateway between the kernel (e.g., selinux) and the user-space audit daemon. 3 * System-call specific features have moved to auditsc.c 4 * 5 * Copyright 2003-2007 Red Hat Inc., Durham, North Carolina. 6 * All Rights Reserved. 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License as published by 10 * the Free Software Foundation; either version 2 of the License, or 11 * (at your option) any later version. 12 * 13 * This program is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 * GNU General Public License for more details. 17 * 18 * You should have received a copy of the GNU General Public License 19 * along with this program; if not, write to the Free Software 20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 21 * 22 * Written by Rickard E. (Rik) Faith <faith@redhat.com> 23 * 24 * Goals: 1) Integrate fully with Security Modules. 25 * 2) Minimal run-time overhead: 26 * a) Minimal when syscall auditing is disabled (audit_enable=0). 27 * b) Small when syscall auditing is enabled and no audit record 28 * is generated (defer as much work as possible to record 29 * generation time): 30 * i) context is allocated, 31 * ii) names from getname are stored without a copy, and 32 * iii) inode information stored from path_lookup. 33 * 3) Ability to disable syscall auditing at boot time (audit=0). 34 * 4) Usable by other parts of the kernel (if audit_log* is called, 35 * then a syscall record will be generated automatically for the 36 * current syscall). 37 * 5) Netlink interface to user-space. 38 * 6) Support low-overhead kernel-based filtering to minimize the 39 * information that must be passed to user-space. 40 * 41 * Example user-space utilities: http://people.redhat.com/sgrubb/audit/ 42 */ 43 44 #include <linux/init.h> 45 #include <asm/types.h> 46 #include <linux/atomic.h> 47 #include <linux/mm.h> 48 #include <linux/export.h> 49 #include <linux/slab.h> 50 #include <linux/err.h> 51 #include <linux/kthread.h> 52 53 #include <linux/audit.h> 54 55 #include <net/sock.h> 56 #include <net/netlink.h> 57 #include <linux/skbuff.h> 58 #ifdef CONFIG_SECURITY 59 #include <linux/security.h> 60 #endif 61 #include <linux/netlink.h> 62 #include <linux/freezer.h> 63 #include <linux/tty.h> 64 #include <linux/pid_namespace.h> 65 66 #include "audit.h" 67 68 /* No auditing will take place until audit_initialized == AUDIT_INITIALIZED. 69 * (Initialization happens after skb_init is called.) */ 70 #define AUDIT_DISABLED -1 71 #define AUDIT_UNINITIALIZED 0 72 #define AUDIT_INITIALIZED 1 73 static int audit_initialized; 74 75 #define AUDIT_OFF 0 76 #define AUDIT_ON 1 77 #define AUDIT_LOCKED 2 78 int audit_enabled; 79 int audit_ever_enabled; 80 81 EXPORT_SYMBOL_GPL(audit_enabled); 82 83 /* Default state when kernel boots without any parameters. */ 84 static int audit_default; 85 86 /* If auditing cannot proceed, audit_failure selects what happens. */ 87 static int audit_failure = AUDIT_FAIL_PRINTK; 88 89 /* 90 * If audit records are to be written to the netlink socket, audit_pid 91 * contains the pid of the auditd process and audit_nlk_portid contains 92 * the portid to use to send netlink messages to that process. 93 */ 94 int audit_pid; 95 static int audit_nlk_portid; 96 97 /* If audit_rate_limit is non-zero, limit the rate of sending audit records 98 * to that number per second. This prevents DoS attacks, but results in 99 * audit records being dropped. */ 100 static int audit_rate_limit; 101 102 /* Number of outstanding audit_buffers allowed. */ 103 static int audit_backlog_limit = 64; 104 static int audit_backlog_wait_time = 60 * HZ; 105 static int audit_backlog_wait_overflow = 0; 106 107 /* The identity of the user shutting down the audit system. */ 108 kuid_t audit_sig_uid = INVALID_UID; 109 pid_t audit_sig_pid = -1; 110 u32 audit_sig_sid = 0; 111 112 /* Records can be lost in several ways: 113 0) [suppressed in audit_alloc] 114 1) out of memory in audit_log_start [kmalloc of struct audit_buffer] 115 2) out of memory in audit_log_move [alloc_skb] 116 3) suppressed due to audit_rate_limit 117 4) suppressed due to audit_backlog_limit 118 */ 119 static atomic_t audit_lost = ATOMIC_INIT(0); 120 121 /* The netlink socket. */ 122 static struct sock *audit_sock; 123 124 /* Hash for inode-based rules */ 125 struct list_head audit_inode_hash[AUDIT_INODE_BUCKETS]; 126 127 /* The audit_freelist is a list of pre-allocated audit buffers (if more 128 * than AUDIT_MAXFREE are in use, the audit buffer is freed instead of 129 * being placed on the freelist). */ 130 static DEFINE_SPINLOCK(audit_freelist_lock); 131 static int audit_freelist_count; 132 static LIST_HEAD(audit_freelist); 133 134 static struct sk_buff_head audit_skb_queue; 135 /* queue of skbs to send to auditd when/if it comes back */ 136 static struct sk_buff_head audit_skb_hold_queue; 137 static struct task_struct *kauditd_task; 138 static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait); 139 static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait); 140 141 /* Serialize requests from userspace. */ 142 DEFINE_MUTEX(audit_cmd_mutex); 143 144 /* AUDIT_BUFSIZ is the size of the temporary buffer used for formatting 145 * audit records. Since printk uses a 1024 byte buffer, this buffer 146 * should be at least that large. */ 147 #define AUDIT_BUFSIZ 1024 148 149 /* AUDIT_MAXFREE is the number of empty audit_buffers we keep on the 150 * audit_freelist. Doing so eliminates many kmalloc/kfree calls. */ 151 #define AUDIT_MAXFREE (2*NR_CPUS) 152 153 /* The audit_buffer is used when formatting an audit record. The caller 154 * locks briefly to get the record off the freelist or to allocate the 155 * buffer, and locks briefly to send the buffer to the netlink layer or 156 * to place it on a transmit queue. Multiple audit_buffers can be in 157 * use simultaneously. */ 158 struct audit_buffer { 159 struct list_head list; 160 struct sk_buff *skb; /* formatted skb ready to send */ 161 struct audit_context *ctx; /* NULL or associated context */ 162 gfp_t gfp_mask; 163 }; 164 165 struct audit_reply { 166 int pid; 167 struct sk_buff *skb; 168 }; 169 170 static void audit_set_pid(struct audit_buffer *ab, pid_t pid) 171 { 172 if (ab) { 173 struct nlmsghdr *nlh = nlmsg_hdr(ab->skb); 174 nlh->nlmsg_pid = pid; 175 } 176 } 177 178 void audit_panic(const char *message) 179 { 180 switch (audit_failure) 181 { 182 case AUDIT_FAIL_SILENT: 183 break; 184 case AUDIT_FAIL_PRINTK: 185 if (printk_ratelimit()) 186 printk(KERN_ERR "audit: %s\n", message); 187 break; 188 case AUDIT_FAIL_PANIC: 189 /* test audit_pid since printk is always losey, why bother? */ 190 if (audit_pid) 191 panic("audit: %s\n", message); 192 break; 193 } 194 } 195 196 static inline int audit_rate_check(void) 197 { 198 static unsigned long last_check = 0; 199 static int messages = 0; 200 static DEFINE_SPINLOCK(lock); 201 unsigned long flags; 202 unsigned long now; 203 unsigned long elapsed; 204 int retval = 0; 205 206 if (!audit_rate_limit) return 1; 207 208 spin_lock_irqsave(&lock, flags); 209 if (++messages < audit_rate_limit) { 210 retval = 1; 211 } else { 212 now = jiffies; 213 elapsed = now - last_check; 214 if (elapsed > HZ) { 215 last_check = now; 216 messages = 0; 217 retval = 1; 218 } 219 } 220 spin_unlock_irqrestore(&lock, flags); 221 222 return retval; 223 } 224 225 /** 226 * audit_log_lost - conditionally log lost audit message event 227 * @message: the message stating reason for lost audit message 228 * 229 * Emit at least 1 message per second, even if audit_rate_check is 230 * throttling. 231 * Always increment the lost messages counter. 232 */ 233 void audit_log_lost(const char *message) 234 { 235 static unsigned long last_msg = 0; 236 static DEFINE_SPINLOCK(lock); 237 unsigned long flags; 238 unsigned long now; 239 int print; 240 241 atomic_inc(&audit_lost); 242 243 print = (audit_failure == AUDIT_FAIL_PANIC || !audit_rate_limit); 244 245 if (!print) { 246 spin_lock_irqsave(&lock, flags); 247 now = jiffies; 248 if (now - last_msg > HZ) { 249 print = 1; 250 last_msg = now; 251 } 252 spin_unlock_irqrestore(&lock, flags); 253 } 254 255 if (print) { 256 if (printk_ratelimit()) 257 printk(KERN_WARNING 258 "audit: audit_lost=%d audit_rate_limit=%d " 259 "audit_backlog_limit=%d\n", 260 atomic_read(&audit_lost), 261 audit_rate_limit, 262 audit_backlog_limit); 263 audit_panic(message); 264 } 265 } 266 267 static int audit_log_config_change(char *function_name, int new, int old, 268 kuid_t loginuid, u32 sessionid, u32 sid, 269 int allow_changes) 270 { 271 struct audit_buffer *ab; 272 int rc = 0; 273 274 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE); 275 if (unlikely(!ab)) 276 return rc; 277 audit_log_format(ab, "%s=%d old=%d auid=%u ses=%u", function_name, new, 278 old, from_kuid(&init_user_ns, loginuid), sessionid); 279 if (sid) { 280 char *ctx = NULL; 281 u32 len; 282 283 rc = security_secid_to_secctx(sid, &ctx, &len); 284 if (rc) { 285 audit_log_format(ab, " sid=%u", sid); 286 allow_changes = 0; /* Something weird, deny request */ 287 } else { 288 audit_log_format(ab, " subj=%s", ctx); 289 security_release_secctx(ctx, len); 290 } 291 } 292 audit_log_format(ab, " res=%d", allow_changes); 293 audit_log_end(ab); 294 return rc; 295 } 296 297 static int audit_do_config_change(char *function_name, int *to_change, 298 int new, kuid_t loginuid, u32 sessionid, 299 u32 sid) 300 { 301 int allow_changes, rc = 0, old = *to_change; 302 303 /* check if we are locked */ 304 if (audit_enabled == AUDIT_LOCKED) 305 allow_changes = 0; 306 else 307 allow_changes = 1; 308 309 if (audit_enabled != AUDIT_OFF) { 310 rc = audit_log_config_change(function_name, new, old, loginuid, 311 sessionid, sid, allow_changes); 312 if (rc) 313 allow_changes = 0; 314 } 315 316 /* If we are allowed, make the change */ 317 if (allow_changes == 1) 318 *to_change = new; 319 /* Not allowed, update reason */ 320 else if (rc == 0) 321 rc = -EPERM; 322 return rc; 323 } 324 325 static int audit_set_rate_limit(int limit, kuid_t loginuid, u32 sessionid, 326 u32 sid) 327 { 328 return audit_do_config_change("audit_rate_limit", &audit_rate_limit, 329 limit, loginuid, sessionid, sid); 330 } 331 332 static int audit_set_backlog_limit(int limit, kuid_t loginuid, u32 sessionid, 333 u32 sid) 334 { 335 return audit_do_config_change("audit_backlog_limit", &audit_backlog_limit, 336 limit, loginuid, sessionid, sid); 337 } 338 339 static int audit_set_enabled(int state, kuid_t loginuid, u32 sessionid, u32 sid) 340 { 341 int rc; 342 if (state < AUDIT_OFF || state > AUDIT_LOCKED) 343 return -EINVAL; 344 345 rc = audit_do_config_change("audit_enabled", &audit_enabled, state, 346 loginuid, sessionid, sid); 347 348 if (!rc) 349 audit_ever_enabled |= !!state; 350 351 return rc; 352 } 353 354 static int audit_set_failure(int state, kuid_t loginuid, u32 sessionid, u32 sid) 355 { 356 if (state != AUDIT_FAIL_SILENT 357 && state != AUDIT_FAIL_PRINTK 358 && state != AUDIT_FAIL_PANIC) 359 return -EINVAL; 360 361 return audit_do_config_change("audit_failure", &audit_failure, state, 362 loginuid, sessionid, sid); 363 } 364 365 /* 366 * Queue skbs to be sent to auditd when/if it comes back. These skbs should 367 * already have been sent via prink/syslog and so if these messages are dropped 368 * it is not a huge concern since we already passed the audit_log_lost() 369 * notification and stuff. This is just nice to get audit messages during 370 * boot before auditd is running or messages generated while auditd is stopped. 371 * This only holds messages is audit_default is set, aka booting with audit=1 372 * or building your kernel that way. 373 */ 374 static void audit_hold_skb(struct sk_buff *skb) 375 { 376 if (audit_default && 377 skb_queue_len(&audit_skb_hold_queue) < audit_backlog_limit) 378 skb_queue_tail(&audit_skb_hold_queue, skb); 379 else 380 kfree_skb(skb); 381 } 382 383 /* 384 * For one reason or another this nlh isn't getting delivered to the userspace 385 * audit daemon, just send it to printk. 386 */ 387 static void audit_printk_skb(struct sk_buff *skb) 388 { 389 struct nlmsghdr *nlh = nlmsg_hdr(skb); 390 char *data = nlmsg_data(nlh); 391 392 if (nlh->nlmsg_type != AUDIT_EOE) { 393 if (printk_ratelimit()) 394 printk(KERN_NOTICE "type=%d %s\n", nlh->nlmsg_type, data); 395 else 396 audit_log_lost("printk limit exceeded\n"); 397 } 398 399 audit_hold_skb(skb); 400 } 401 402 static void kauditd_send_skb(struct sk_buff *skb) 403 { 404 int err; 405 /* take a reference in case we can't send it and we want to hold it */ 406 skb_get(skb); 407 err = netlink_unicast(audit_sock, skb, audit_nlk_portid, 0); 408 if (err < 0) { 409 BUG_ON(err != -ECONNREFUSED); /* Shouldn't happen */ 410 printk(KERN_ERR "audit: *NO* daemon at audit_pid=%d\n", audit_pid); 411 audit_log_lost("auditd disappeared\n"); 412 audit_pid = 0; 413 /* we might get lucky and get this in the next auditd */ 414 audit_hold_skb(skb); 415 } else 416 /* drop the extra reference if sent ok */ 417 consume_skb(skb); 418 } 419 420 static int kauditd_thread(void *dummy) 421 { 422 struct sk_buff *skb; 423 424 set_freezable(); 425 while (!kthread_should_stop()) { 426 /* 427 * if auditd just started drain the queue of messages already 428 * sent to syslog/printk. remember loss here is ok. we already 429 * called audit_log_lost() if it didn't go out normally. so the 430 * race between the skb_dequeue and the next check for audit_pid 431 * doesn't matter. 432 * 433 * if you ever find kauditd to be too slow we can get a perf win 434 * by doing our own locking and keeping better track if there 435 * are messages in this queue. I don't see the need now, but 436 * in 5 years when I want to play with this again I'll see this 437 * note and still have no friggin idea what i'm thinking today. 438 */ 439 if (audit_default && audit_pid) { 440 skb = skb_dequeue(&audit_skb_hold_queue); 441 if (unlikely(skb)) { 442 while (skb && audit_pid) { 443 kauditd_send_skb(skb); 444 skb = skb_dequeue(&audit_skb_hold_queue); 445 } 446 } 447 } 448 449 skb = skb_dequeue(&audit_skb_queue); 450 wake_up(&audit_backlog_wait); 451 if (skb) { 452 if (audit_pid) 453 kauditd_send_skb(skb); 454 else 455 audit_printk_skb(skb); 456 } else { 457 DECLARE_WAITQUEUE(wait, current); 458 set_current_state(TASK_INTERRUPTIBLE); 459 add_wait_queue(&kauditd_wait, &wait); 460 461 if (!skb_queue_len(&audit_skb_queue)) { 462 try_to_freeze(); 463 schedule(); 464 } 465 466 __set_current_state(TASK_RUNNING); 467 remove_wait_queue(&kauditd_wait, &wait); 468 } 469 } 470 return 0; 471 } 472 473 int audit_send_list(void *_dest) 474 { 475 struct audit_netlink_list *dest = _dest; 476 int pid = dest->pid; 477 struct sk_buff *skb; 478 479 /* wait for parent to finish and send an ACK */ 480 mutex_lock(&audit_cmd_mutex); 481 mutex_unlock(&audit_cmd_mutex); 482 483 while ((skb = __skb_dequeue(&dest->q)) != NULL) 484 netlink_unicast(audit_sock, skb, pid, 0); 485 486 kfree(dest); 487 488 return 0; 489 } 490 491 struct sk_buff *audit_make_reply(int pid, int seq, int type, int done, 492 int multi, const void *payload, int size) 493 { 494 struct sk_buff *skb; 495 struct nlmsghdr *nlh; 496 void *data; 497 int flags = multi ? NLM_F_MULTI : 0; 498 int t = done ? NLMSG_DONE : type; 499 500 skb = nlmsg_new(size, GFP_KERNEL); 501 if (!skb) 502 return NULL; 503 504 nlh = nlmsg_put(skb, pid, seq, t, size, flags); 505 if (!nlh) 506 goto out_kfree_skb; 507 data = nlmsg_data(nlh); 508 memcpy(data, payload, size); 509 return skb; 510 511 out_kfree_skb: 512 kfree_skb(skb); 513 return NULL; 514 } 515 516 static int audit_send_reply_thread(void *arg) 517 { 518 struct audit_reply *reply = (struct audit_reply *)arg; 519 520 mutex_lock(&audit_cmd_mutex); 521 mutex_unlock(&audit_cmd_mutex); 522 523 /* Ignore failure. It'll only happen if the sender goes away, 524 because our timeout is set to infinite. */ 525 netlink_unicast(audit_sock, reply->skb, reply->pid, 0); 526 kfree(reply); 527 return 0; 528 } 529 /** 530 * audit_send_reply - send an audit reply message via netlink 531 * @pid: process id to send reply to 532 * @seq: sequence number 533 * @type: audit message type 534 * @done: done (last) flag 535 * @multi: multi-part message flag 536 * @payload: payload data 537 * @size: payload size 538 * 539 * Allocates an skb, builds the netlink message, and sends it to the pid. 540 * No failure notifications. 541 */ 542 static void audit_send_reply(int pid, int seq, int type, int done, int multi, 543 const void *payload, int size) 544 { 545 struct sk_buff *skb; 546 struct task_struct *tsk; 547 struct audit_reply *reply = kmalloc(sizeof(struct audit_reply), 548 GFP_KERNEL); 549 550 if (!reply) 551 return; 552 553 skb = audit_make_reply(pid, seq, type, done, multi, payload, size); 554 if (!skb) 555 goto out; 556 557 reply->pid = pid; 558 reply->skb = skb; 559 560 tsk = kthread_run(audit_send_reply_thread, reply, "audit_send_reply"); 561 if (!IS_ERR(tsk)) 562 return; 563 kfree_skb(skb); 564 out: 565 kfree(reply); 566 } 567 568 /* 569 * Check for appropriate CAP_AUDIT_ capabilities on incoming audit 570 * control messages. 571 */ 572 static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type) 573 { 574 int err = 0; 575 576 /* Only support the initial namespaces for now. */ 577 if ((current_user_ns() != &init_user_ns) || 578 (task_active_pid_ns(current) != &init_pid_ns)) 579 return -EPERM; 580 581 switch (msg_type) { 582 case AUDIT_GET: 583 case AUDIT_LIST: 584 case AUDIT_LIST_RULES: 585 case AUDIT_SET: 586 case AUDIT_ADD: 587 case AUDIT_ADD_RULE: 588 case AUDIT_DEL: 589 case AUDIT_DEL_RULE: 590 case AUDIT_SIGNAL_INFO: 591 case AUDIT_TTY_GET: 592 case AUDIT_TTY_SET: 593 case AUDIT_TRIM: 594 case AUDIT_MAKE_EQUIV: 595 if (!capable(CAP_AUDIT_CONTROL)) 596 err = -EPERM; 597 break; 598 case AUDIT_USER: 599 case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG: 600 case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2: 601 if (!capable(CAP_AUDIT_WRITE)) 602 err = -EPERM; 603 break; 604 default: /* bad msg */ 605 err = -EINVAL; 606 } 607 608 return err; 609 } 610 611 static int audit_log_common_recv_msg(struct audit_buffer **ab, u16 msg_type, 612 kuid_t auid, u32 ses, u32 sid) 613 { 614 int rc = 0; 615 char *ctx = NULL; 616 u32 len; 617 618 if (!audit_enabled) { 619 *ab = NULL; 620 return rc; 621 } 622 623 *ab = audit_log_start(NULL, GFP_KERNEL, msg_type); 624 if (unlikely(!*ab)) 625 return rc; 626 audit_log_format(*ab, "pid=%d uid=%u auid=%u ses=%u", 627 task_tgid_vnr(current), 628 from_kuid(&init_user_ns, current_uid()), 629 from_kuid(&init_user_ns, auid), ses); 630 if (sid) { 631 rc = security_secid_to_secctx(sid, &ctx, &len); 632 if (rc) 633 audit_log_format(*ab, " ssid=%u", sid); 634 else { 635 audit_log_format(*ab, " subj=%s", ctx); 636 security_release_secctx(ctx, len); 637 } 638 } 639 640 return rc; 641 } 642 643 static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) 644 { 645 u32 seq, sid; 646 void *data; 647 struct audit_status *status_get, status_set; 648 int err; 649 struct audit_buffer *ab; 650 u16 msg_type = nlh->nlmsg_type; 651 kuid_t loginuid; /* loginuid of sender */ 652 u32 sessionid; 653 struct audit_sig_info *sig_data; 654 char *ctx = NULL; 655 u32 len; 656 657 err = audit_netlink_ok(skb, msg_type); 658 if (err) 659 return err; 660 661 /* As soon as there's any sign of userspace auditd, 662 * start kauditd to talk to it */ 663 if (!kauditd_task) 664 kauditd_task = kthread_run(kauditd_thread, NULL, "kauditd"); 665 if (IS_ERR(kauditd_task)) { 666 err = PTR_ERR(kauditd_task); 667 kauditd_task = NULL; 668 return err; 669 } 670 671 loginuid = audit_get_loginuid(current); 672 sessionid = audit_get_sessionid(current); 673 security_task_getsecid(current, &sid); 674 seq = nlh->nlmsg_seq; 675 data = nlmsg_data(nlh); 676 677 switch (msg_type) { 678 case AUDIT_GET: 679 status_set.enabled = audit_enabled; 680 status_set.failure = audit_failure; 681 status_set.pid = audit_pid; 682 status_set.rate_limit = audit_rate_limit; 683 status_set.backlog_limit = audit_backlog_limit; 684 status_set.lost = atomic_read(&audit_lost); 685 status_set.backlog = skb_queue_len(&audit_skb_queue); 686 audit_send_reply(NETLINK_CB(skb).portid, seq, AUDIT_GET, 0, 0, 687 &status_set, sizeof(status_set)); 688 break; 689 case AUDIT_SET: 690 if (nlh->nlmsg_len < sizeof(struct audit_status)) 691 return -EINVAL; 692 status_get = (struct audit_status *)data; 693 if (status_get->mask & AUDIT_STATUS_ENABLED) { 694 err = audit_set_enabled(status_get->enabled, 695 loginuid, sessionid, sid); 696 if (err < 0) 697 return err; 698 } 699 if (status_get->mask & AUDIT_STATUS_FAILURE) { 700 err = audit_set_failure(status_get->failure, 701 loginuid, sessionid, sid); 702 if (err < 0) 703 return err; 704 } 705 if (status_get->mask & AUDIT_STATUS_PID) { 706 int new_pid = status_get->pid; 707 708 if (audit_enabled != AUDIT_OFF) 709 audit_log_config_change("audit_pid", new_pid, 710 audit_pid, loginuid, 711 sessionid, sid, 1); 712 713 audit_pid = new_pid; 714 audit_nlk_portid = NETLINK_CB(skb).portid; 715 } 716 if (status_get->mask & AUDIT_STATUS_RATE_LIMIT) { 717 err = audit_set_rate_limit(status_get->rate_limit, 718 loginuid, sessionid, sid); 719 if (err < 0) 720 return err; 721 } 722 if (status_get->mask & AUDIT_STATUS_BACKLOG_LIMIT) 723 err = audit_set_backlog_limit(status_get->backlog_limit, 724 loginuid, sessionid, sid); 725 break; 726 case AUDIT_USER: 727 case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG: 728 case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2: 729 if (!audit_enabled && msg_type != AUDIT_USER_AVC) 730 return 0; 731 732 err = audit_filter_user(); 733 if (err == 1) { 734 err = 0; 735 if (msg_type == AUDIT_USER_TTY) { 736 err = tty_audit_push_task(current, loginuid, 737 sessionid); 738 if (err) 739 break; 740 } 741 audit_log_common_recv_msg(&ab, msg_type, 742 loginuid, sessionid, sid); 743 744 if (msg_type != AUDIT_USER_TTY) 745 audit_log_format(ab, " msg='%.1024s'", 746 (char *)data); 747 else { 748 int size; 749 750 audit_log_format(ab, " msg="); 751 size = nlmsg_len(nlh); 752 if (size > 0 && 753 ((unsigned char *)data)[size - 1] == '\0') 754 size--; 755 audit_log_n_untrustedstring(ab, data, size); 756 } 757 audit_set_pid(ab, NETLINK_CB(skb).portid); 758 audit_log_end(ab); 759 } 760 break; 761 case AUDIT_ADD: 762 case AUDIT_DEL: 763 if (nlmsg_len(nlh) < sizeof(struct audit_rule)) 764 return -EINVAL; 765 if (audit_enabled == AUDIT_LOCKED) { 766 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE, 767 loginuid, sessionid, sid); 768 769 audit_log_format(ab, " audit_enabled=%d res=0", 770 audit_enabled); 771 audit_log_end(ab); 772 return -EPERM; 773 } 774 /* fallthrough */ 775 case AUDIT_LIST: 776 err = audit_receive_filter(msg_type, NETLINK_CB(skb).portid, 777 seq, data, nlmsg_len(nlh), 778 loginuid, sessionid, sid); 779 break; 780 case AUDIT_ADD_RULE: 781 case AUDIT_DEL_RULE: 782 if (nlmsg_len(nlh) < sizeof(struct audit_rule_data)) 783 return -EINVAL; 784 if (audit_enabled == AUDIT_LOCKED) { 785 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE, 786 loginuid, sessionid, sid); 787 788 audit_log_format(ab, " audit_enabled=%d res=0", 789 audit_enabled); 790 audit_log_end(ab); 791 return -EPERM; 792 } 793 /* fallthrough */ 794 case AUDIT_LIST_RULES: 795 err = audit_receive_filter(msg_type, NETLINK_CB(skb).portid, 796 seq, data, nlmsg_len(nlh), 797 loginuid, sessionid, sid); 798 break; 799 case AUDIT_TRIM: 800 audit_trim_trees(); 801 802 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE, 803 loginuid, sessionid, sid); 804 805 audit_log_format(ab, " op=trim res=1"); 806 audit_log_end(ab); 807 break; 808 case AUDIT_MAKE_EQUIV: { 809 void *bufp = data; 810 u32 sizes[2]; 811 size_t msglen = nlmsg_len(nlh); 812 char *old, *new; 813 814 err = -EINVAL; 815 if (msglen < 2 * sizeof(u32)) 816 break; 817 memcpy(sizes, bufp, 2 * sizeof(u32)); 818 bufp += 2 * sizeof(u32); 819 msglen -= 2 * sizeof(u32); 820 old = audit_unpack_string(&bufp, &msglen, sizes[0]); 821 if (IS_ERR(old)) { 822 err = PTR_ERR(old); 823 break; 824 } 825 new = audit_unpack_string(&bufp, &msglen, sizes[1]); 826 if (IS_ERR(new)) { 827 err = PTR_ERR(new); 828 kfree(old); 829 break; 830 } 831 /* OK, here comes... */ 832 err = audit_tag_tree(old, new); 833 834 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE, 835 loginuid, sessionid, sid); 836 837 audit_log_format(ab, " op=make_equiv old="); 838 audit_log_untrustedstring(ab, old); 839 audit_log_format(ab, " new="); 840 audit_log_untrustedstring(ab, new); 841 audit_log_format(ab, " res=%d", !err); 842 audit_log_end(ab); 843 kfree(old); 844 kfree(new); 845 break; 846 } 847 case AUDIT_SIGNAL_INFO: 848 len = 0; 849 if (audit_sig_sid) { 850 err = security_secid_to_secctx(audit_sig_sid, &ctx, &len); 851 if (err) 852 return err; 853 } 854 sig_data = kmalloc(sizeof(*sig_data) + len, GFP_KERNEL); 855 if (!sig_data) { 856 if (audit_sig_sid) 857 security_release_secctx(ctx, len); 858 return -ENOMEM; 859 } 860 sig_data->uid = from_kuid(&init_user_ns, audit_sig_uid); 861 sig_data->pid = audit_sig_pid; 862 if (audit_sig_sid) { 863 memcpy(sig_data->ctx, ctx, len); 864 security_release_secctx(ctx, len); 865 } 866 audit_send_reply(NETLINK_CB(skb).portid, seq, AUDIT_SIGNAL_INFO, 867 0, 0, sig_data, sizeof(*sig_data) + len); 868 kfree(sig_data); 869 break; 870 case AUDIT_TTY_GET: { 871 struct audit_tty_status s; 872 struct task_struct *tsk = current; 873 874 spin_lock_irq(&tsk->sighand->siglock); 875 s.enabled = tsk->signal->audit_tty != 0; 876 spin_unlock_irq(&tsk->sighand->siglock); 877 878 audit_send_reply(NETLINK_CB(skb).portid, seq, 879 AUDIT_TTY_GET, 0, 0, &s, sizeof(s)); 880 break; 881 } 882 case AUDIT_TTY_SET: { 883 struct audit_tty_status *s; 884 struct task_struct *tsk = current; 885 886 if (nlh->nlmsg_len < sizeof(struct audit_tty_status)) 887 return -EINVAL; 888 s = data; 889 if (s->enabled != 0 && s->enabled != 1) 890 return -EINVAL; 891 892 spin_lock_irq(&tsk->sighand->siglock); 893 tsk->signal->audit_tty = s->enabled != 0; 894 spin_unlock_irq(&tsk->sighand->siglock); 895 break; 896 } 897 default: 898 err = -EINVAL; 899 break; 900 } 901 902 return err < 0 ? err : 0; 903 } 904 905 /* 906 * Get message from skb. Each message is processed by audit_receive_msg. 907 * Malformed skbs with wrong length are discarded silently. 908 */ 909 static void audit_receive_skb(struct sk_buff *skb) 910 { 911 struct nlmsghdr *nlh; 912 /* 913 * len MUST be signed for NLMSG_NEXT to be able to dec it below 0 914 * if the nlmsg_len was not aligned 915 */ 916 int len; 917 int err; 918 919 nlh = nlmsg_hdr(skb); 920 len = skb->len; 921 922 while (NLMSG_OK(nlh, len)) { 923 err = audit_receive_msg(skb, nlh); 924 /* if err or if this message says it wants a response */ 925 if (err || (nlh->nlmsg_flags & NLM_F_ACK)) 926 netlink_ack(skb, nlh, err); 927 928 nlh = NLMSG_NEXT(nlh, len); 929 } 930 } 931 932 /* Receive messages from netlink socket. */ 933 static void audit_receive(struct sk_buff *skb) 934 { 935 mutex_lock(&audit_cmd_mutex); 936 audit_receive_skb(skb); 937 mutex_unlock(&audit_cmd_mutex); 938 } 939 940 /* Initialize audit support at boot time. */ 941 static int __init audit_init(void) 942 { 943 int i; 944 struct netlink_kernel_cfg cfg = { 945 .input = audit_receive, 946 }; 947 948 if (audit_initialized == AUDIT_DISABLED) 949 return 0; 950 951 printk(KERN_INFO "audit: initializing netlink socket (%s)\n", 952 audit_default ? "enabled" : "disabled"); 953 audit_sock = netlink_kernel_create(&init_net, NETLINK_AUDIT, &cfg); 954 if (!audit_sock) 955 audit_panic("cannot initialize netlink socket"); 956 else 957 audit_sock->sk_sndtimeo = MAX_SCHEDULE_TIMEOUT; 958 959 skb_queue_head_init(&audit_skb_queue); 960 skb_queue_head_init(&audit_skb_hold_queue); 961 audit_initialized = AUDIT_INITIALIZED; 962 audit_enabled = audit_default; 963 audit_ever_enabled |= !!audit_default; 964 965 audit_log(NULL, GFP_KERNEL, AUDIT_KERNEL, "initialized"); 966 967 for (i = 0; i < AUDIT_INODE_BUCKETS; i++) 968 INIT_LIST_HEAD(&audit_inode_hash[i]); 969 970 return 0; 971 } 972 __initcall(audit_init); 973 974 /* Process kernel command-line parameter at boot time. audit=0 or audit=1. */ 975 static int __init audit_enable(char *str) 976 { 977 audit_default = !!simple_strtol(str, NULL, 0); 978 if (!audit_default) 979 audit_initialized = AUDIT_DISABLED; 980 981 printk(KERN_INFO "audit: %s", audit_default ? "enabled" : "disabled"); 982 983 if (audit_initialized == AUDIT_INITIALIZED) { 984 audit_enabled = audit_default; 985 audit_ever_enabled |= !!audit_default; 986 } else if (audit_initialized == AUDIT_UNINITIALIZED) { 987 printk(" (after initialization)"); 988 } else { 989 printk(" (until reboot)"); 990 } 991 printk("\n"); 992 993 return 1; 994 } 995 996 __setup("audit=", audit_enable); 997 998 static void audit_buffer_free(struct audit_buffer *ab) 999 { 1000 unsigned long flags; 1001 1002 if (!ab) 1003 return; 1004 1005 if (ab->skb) 1006 kfree_skb(ab->skb); 1007 1008 spin_lock_irqsave(&audit_freelist_lock, flags); 1009 if (audit_freelist_count > AUDIT_MAXFREE) 1010 kfree(ab); 1011 else { 1012 audit_freelist_count++; 1013 list_add(&ab->list, &audit_freelist); 1014 } 1015 spin_unlock_irqrestore(&audit_freelist_lock, flags); 1016 } 1017 1018 static struct audit_buffer * audit_buffer_alloc(struct audit_context *ctx, 1019 gfp_t gfp_mask, int type) 1020 { 1021 unsigned long flags; 1022 struct audit_buffer *ab = NULL; 1023 struct nlmsghdr *nlh; 1024 1025 spin_lock_irqsave(&audit_freelist_lock, flags); 1026 if (!list_empty(&audit_freelist)) { 1027 ab = list_entry(audit_freelist.next, 1028 struct audit_buffer, list); 1029 list_del(&ab->list); 1030 --audit_freelist_count; 1031 } 1032 spin_unlock_irqrestore(&audit_freelist_lock, flags); 1033 1034 if (!ab) { 1035 ab = kmalloc(sizeof(*ab), gfp_mask); 1036 if (!ab) 1037 goto err; 1038 } 1039 1040 ab->ctx = ctx; 1041 ab->gfp_mask = gfp_mask; 1042 1043 ab->skb = nlmsg_new(AUDIT_BUFSIZ, gfp_mask); 1044 if (!ab->skb) 1045 goto err; 1046 1047 nlh = nlmsg_put(ab->skb, 0, 0, type, 0, 0); 1048 if (!nlh) 1049 goto out_kfree_skb; 1050 1051 return ab; 1052 1053 out_kfree_skb: 1054 kfree_skb(ab->skb); 1055 ab->skb = NULL; 1056 err: 1057 audit_buffer_free(ab); 1058 return NULL; 1059 } 1060 1061 /** 1062 * audit_serial - compute a serial number for the audit record 1063 * 1064 * Compute a serial number for the audit record. Audit records are 1065 * written to user-space as soon as they are generated, so a complete 1066 * audit record may be written in several pieces. The timestamp of the 1067 * record and this serial number are used by the user-space tools to 1068 * determine which pieces belong to the same audit record. The 1069 * (timestamp,serial) tuple is unique for each syscall and is live from 1070 * syscall entry to syscall exit. 1071 * 1072 * NOTE: Another possibility is to store the formatted records off the 1073 * audit context (for those records that have a context), and emit them 1074 * all at syscall exit. However, this could delay the reporting of 1075 * significant errors until syscall exit (or never, if the system 1076 * halts). 1077 */ 1078 unsigned int audit_serial(void) 1079 { 1080 static DEFINE_SPINLOCK(serial_lock); 1081 static unsigned int serial = 0; 1082 1083 unsigned long flags; 1084 unsigned int ret; 1085 1086 spin_lock_irqsave(&serial_lock, flags); 1087 do { 1088 ret = ++serial; 1089 } while (unlikely(!ret)); 1090 spin_unlock_irqrestore(&serial_lock, flags); 1091 1092 return ret; 1093 } 1094 1095 static inline void audit_get_stamp(struct audit_context *ctx, 1096 struct timespec *t, unsigned int *serial) 1097 { 1098 if (!ctx || !auditsc_get_stamp(ctx, t, serial)) { 1099 *t = CURRENT_TIME; 1100 *serial = audit_serial(); 1101 } 1102 } 1103 1104 /* 1105 * Wait for auditd to drain the queue a little 1106 */ 1107 static void wait_for_auditd(unsigned long sleep_time) 1108 { 1109 DECLARE_WAITQUEUE(wait, current); 1110 set_current_state(TASK_INTERRUPTIBLE); 1111 add_wait_queue(&audit_backlog_wait, &wait); 1112 1113 if (audit_backlog_limit && 1114 skb_queue_len(&audit_skb_queue) > audit_backlog_limit) 1115 schedule_timeout(sleep_time); 1116 1117 __set_current_state(TASK_RUNNING); 1118 remove_wait_queue(&audit_backlog_wait, &wait); 1119 } 1120 1121 /* Obtain an audit buffer. This routine does locking to obtain the 1122 * audit buffer, but then no locking is required for calls to 1123 * audit_log_*format. If the tsk is a task that is currently in a 1124 * syscall, then the syscall is marked as auditable and an audit record 1125 * will be written at syscall exit. If there is no associated task, tsk 1126 * should be NULL. */ 1127 1128 /** 1129 * audit_log_start - obtain an audit buffer 1130 * @ctx: audit_context (may be NULL) 1131 * @gfp_mask: type of allocation 1132 * @type: audit message type 1133 * 1134 * Returns audit_buffer pointer on success or NULL on error. 1135 * 1136 * Obtain an audit buffer. This routine does locking to obtain the 1137 * audit buffer, but then no locking is required for calls to 1138 * audit_log_*format. If the task (ctx) is a task that is currently in a 1139 * syscall, then the syscall is marked as auditable and an audit record 1140 * will be written at syscall exit. If there is no associated task, then 1141 * task context (ctx) should be NULL. 1142 */ 1143 struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask, 1144 int type) 1145 { 1146 struct audit_buffer *ab = NULL; 1147 struct timespec t; 1148 unsigned int uninitialized_var(serial); 1149 int reserve; 1150 unsigned long timeout_start = jiffies; 1151 1152 if (audit_initialized != AUDIT_INITIALIZED) 1153 return NULL; 1154 1155 if (unlikely(audit_filter_type(type))) 1156 return NULL; 1157 1158 if (gfp_mask & __GFP_WAIT) 1159 reserve = 0; 1160 else 1161 reserve = 5; /* Allow atomic callers to go up to five 1162 entries over the normal backlog limit */ 1163 1164 while (audit_backlog_limit 1165 && skb_queue_len(&audit_skb_queue) > audit_backlog_limit + reserve) { 1166 if (gfp_mask & __GFP_WAIT && audit_backlog_wait_time) { 1167 unsigned long sleep_time; 1168 1169 sleep_time = timeout_start + audit_backlog_wait_time - 1170 jiffies; 1171 if ((long)sleep_time > 0) 1172 wait_for_auditd(sleep_time); 1173 continue; 1174 } 1175 if (audit_rate_check() && printk_ratelimit()) 1176 printk(KERN_WARNING 1177 "audit: audit_backlog=%d > " 1178 "audit_backlog_limit=%d\n", 1179 skb_queue_len(&audit_skb_queue), 1180 audit_backlog_limit); 1181 audit_log_lost("backlog limit exceeded"); 1182 audit_backlog_wait_time = audit_backlog_wait_overflow; 1183 wake_up(&audit_backlog_wait); 1184 return NULL; 1185 } 1186 1187 ab = audit_buffer_alloc(ctx, gfp_mask, type); 1188 if (!ab) { 1189 audit_log_lost("out of memory in audit_log_start"); 1190 return NULL; 1191 } 1192 1193 audit_get_stamp(ab->ctx, &t, &serial); 1194 1195 audit_log_format(ab, "audit(%lu.%03lu:%u): ", 1196 t.tv_sec, t.tv_nsec/1000000, serial); 1197 return ab; 1198 } 1199 1200 /** 1201 * audit_expand - expand skb in the audit buffer 1202 * @ab: audit_buffer 1203 * @extra: space to add at tail of the skb 1204 * 1205 * Returns 0 (no space) on failed expansion, or available space if 1206 * successful. 1207 */ 1208 static inline int audit_expand(struct audit_buffer *ab, int extra) 1209 { 1210 struct sk_buff *skb = ab->skb; 1211 int oldtail = skb_tailroom(skb); 1212 int ret = pskb_expand_head(skb, 0, extra, ab->gfp_mask); 1213 int newtail = skb_tailroom(skb); 1214 1215 if (ret < 0) { 1216 audit_log_lost("out of memory in audit_expand"); 1217 return 0; 1218 } 1219 1220 skb->truesize += newtail - oldtail; 1221 return newtail; 1222 } 1223 1224 /* 1225 * Format an audit message into the audit buffer. If there isn't enough 1226 * room in the audit buffer, more room will be allocated and vsnprint 1227 * will be called a second time. Currently, we assume that a printk 1228 * can't format message larger than 1024 bytes, so we don't either. 1229 */ 1230 static void audit_log_vformat(struct audit_buffer *ab, const char *fmt, 1231 va_list args) 1232 { 1233 int len, avail; 1234 struct sk_buff *skb; 1235 va_list args2; 1236 1237 if (!ab) 1238 return; 1239 1240 BUG_ON(!ab->skb); 1241 skb = ab->skb; 1242 avail = skb_tailroom(skb); 1243 if (avail == 0) { 1244 avail = audit_expand(ab, AUDIT_BUFSIZ); 1245 if (!avail) 1246 goto out; 1247 } 1248 va_copy(args2, args); 1249 len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args); 1250 if (len >= avail) { 1251 /* The printk buffer is 1024 bytes long, so if we get 1252 * here and AUDIT_BUFSIZ is at least 1024, then we can 1253 * log everything that printk could have logged. */ 1254 avail = audit_expand(ab, 1255 max_t(unsigned, AUDIT_BUFSIZ, 1+len-avail)); 1256 if (!avail) 1257 goto out_va_end; 1258 len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args2); 1259 } 1260 if (len > 0) 1261 skb_put(skb, len); 1262 out_va_end: 1263 va_end(args2); 1264 out: 1265 return; 1266 } 1267 1268 /** 1269 * audit_log_format - format a message into the audit buffer. 1270 * @ab: audit_buffer 1271 * @fmt: format string 1272 * @...: optional parameters matching @fmt string 1273 * 1274 * All the work is done in audit_log_vformat. 1275 */ 1276 void audit_log_format(struct audit_buffer *ab, const char *fmt, ...) 1277 { 1278 va_list args; 1279 1280 if (!ab) 1281 return; 1282 va_start(args, fmt); 1283 audit_log_vformat(ab, fmt, args); 1284 va_end(args); 1285 } 1286 1287 /** 1288 * audit_log_hex - convert a buffer to hex and append it to the audit skb 1289 * @ab: the audit_buffer 1290 * @buf: buffer to convert to hex 1291 * @len: length of @buf to be converted 1292 * 1293 * No return value; failure to expand is silently ignored. 1294 * 1295 * This function will take the passed buf and convert it into a string of 1296 * ascii hex digits. The new string is placed onto the skb. 1297 */ 1298 void audit_log_n_hex(struct audit_buffer *ab, const unsigned char *buf, 1299 size_t len) 1300 { 1301 int i, avail, new_len; 1302 unsigned char *ptr; 1303 struct sk_buff *skb; 1304 static const unsigned char *hex = "0123456789ABCDEF"; 1305 1306 if (!ab) 1307 return; 1308 1309 BUG_ON(!ab->skb); 1310 skb = ab->skb; 1311 avail = skb_tailroom(skb); 1312 new_len = len<<1; 1313 if (new_len >= avail) { 1314 /* Round the buffer request up to the next multiple */ 1315 new_len = AUDIT_BUFSIZ*(((new_len-avail)/AUDIT_BUFSIZ) + 1); 1316 avail = audit_expand(ab, new_len); 1317 if (!avail) 1318 return; 1319 } 1320 1321 ptr = skb_tail_pointer(skb); 1322 for (i=0; i<len; i++) { 1323 *ptr++ = hex[(buf[i] & 0xF0)>>4]; /* Upper nibble */ 1324 *ptr++ = hex[buf[i] & 0x0F]; /* Lower nibble */ 1325 } 1326 *ptr = 0; 1327 skb_put(skb, len << 1); /* new string is twice the old string */ 1328 } 1329 1330 /* 1331 * Format a string of no more than slen characters into the audit buffer, 1332 * enclosed in quote marks. 1333 */ 1334 void audit_log_n_string(struct audit_buffer *ab, const char *string, 1335 size_t slen) 1336 { 1337 int avail, new_len; 1338 unsigned char *ptr; 1339 struct sk_buff *skb; 1340 1341 if (!ab) 1342 return; 1343 1344 BUG_ON(!ab->skb); 1345 skb = ab->skb; 1346 avail = skb_tailroom(skb); 1347 new_len = slen + 3; /* enclosing quotes + null terminator */ 1348 if (new_len > avail) { 1349 avail = audit_expand(ab, new_len); 1350 if (!avail) 1351 return; 1352 } 1353 ptr = skb_tail_pointer(skb); 1354 *ptr++ = '"'; 1355 memcpy(ptr, string, slen); 1356 ptr += slen; 1357 *ptr++ = '"'; 1358 *ptr = 0; 1359 skb_put(skb, slen + 2); /* don't include null terminator */ 1360 } 1361 1362 /** 1363 * audit_string_contains_control - does a string need to be logged in hex 1364 * @string: string to be checked 1365 * @len: max length of the string to check 1366 */ 1367 int audit_string_contains_control(const char *string, size_t len) 1368 { 1369 const unsigned char *p; 1370 for (p = string; p < (const unsigned char *)string + len; p++) { 1371 if (*p == '"' || *p < 0x21 || *p > 0x7e) 1372 return 1; 1373 } 1374 return 0; 1375 } 1376 1377 /** 1378 * audit_log_n_untrustedstring - log a string that may contain random characters 1379 * @ab: audit_buffer 1380 * @len: length of string (not including trailing null) 1381 * @string: string to be logged 1382 * 1383 * This code will escape a string that is passed to it if the string 1384 * contains a control character, unprintable character, double quote mark, 1385 * or a space. Unescaped strings will start and end with a double quote mark. 1386 * Strings that are escaped are printed in hex (2 digits per char). 1387 * 1388 * The caller specifies the number of characters in the string to log, which may 1389 * or may not be the entire string. 1390 */ 1391 void audit_log_n_untrustedstring(struct audit_buffer *ab, const char *string, 1392 size_t len) 1393 { 1394 if (audit_string_contains_control(string, len)) 1395 audit_log_n_hex(ab, string, len); 1396 else 1397 audit_log_n_string(ab, string, len); 1398 } 1399 1400 /** 1401 * audit_log_untrustedstring - log a string that may contain random characters 1402 * @ab: audit_buffer 1403 * @string: string to be logged 1404 * 1405 * Same as audit_log_n_untrustedstring(), except that strlen is used to 1406 * determine string length. 1407 */ 1408 void audit_log_untrustedstring(struct audit_buffer *ab, const char *string) 1409 { 1410 audit_log_n_untrustedstring(ab, string, strlen(string)); 1411 } 1412 1413 /* This is a helper-function to print the escaped d_path */ 1414 void audit_log_d_path(struct audit_buffer *ab, const char *prefix, 1415 const struct path *path) 1416 { 1417 char *p, *pathname; 1418 1419 if (prefix) 1420 audit_log_format(ab, "%s", prefix); 1421 1422 /* We will allow 11 spaces for ' (deleted)' to be appended */ 1423 pathname = kmalloc(PATH_MAX+11, ab->gfp_mask); 1424 if (!pathname) { 1425 audit_log_string(ab, "<no_memory>"); 1426 return; 1427 } 1428 p = d_path(path, pathname, PATH_MAX+11); 1429 if (IS_ERR(p)) { /* Should never happen since we send PATH_MAX */ 1430 /* FIXME: can we save some information here? */ 1431 audit_log_string(ab, "<too_long>"); 1432 } else 1433 audit_log_untrustedstring(ab, p); 1434 kfree(pathname); 1435 } 1436 1437 void audit_log_key(struct audit_buffer *ab, char *key) 1438 { 1439 audit_log_format(ab, " key="); 1440 if (key) 1441 audit_log_untrustedstring(ab, key); 1442 else 1443 audit_log_format(ab, "(null)"); 1444 } 1445 1446 /** 1447 * audit_log_link_denied - report a link restriction denial 1448 * @operation: specific link opreation 1449 * @link: the path that triggered the restriction 1450 */ 1451 void audit_log_link_denied(const char *operation, struct path *link) 1452 { 1453 struct audit_buffer *ab; 1454 1455 ab = audit_log_start(current->audit_context, GFP_KERNEL, 1456 AUDIT_ANOM_LINK); 1457 if (!ab) 1458 return; 1459 audit_log_format(ab, "op=%s action=denied", operation); 1460 audit_log_format(ab, " pid=%d comm=", current->pid); 1461 audit_log_untrustedstring(ab, current->comm); 1462 audit_log_d_path(ab, " path=", link); 1463 audit_log_format(ab, " dev="); 1464 audit_log_untrustedstring(ab, link->dentry->d_inode->i_sb->s_id); 1465 audit_log_format(ab, " ino=%lu", link->dentry->d_inode->i_ino); 1466 audit_log_end(ab); 1467 } 1468 1469 /** 1470 * audit_log_end - end one audit record 1471 * @ab: the audit_buffer 1472 * 1473 * The netlink_* functions cannot be called inside an irq context, so 1474 * the audit buffer is placed on a queue and a tasklet is scheduled to 1475 * remove them from the queue outside the irq context. May be called in 1476 * any context. 1477 */ 1478 void audit_log_end(struct audit_buffer *ab) 1479 { 1480 if (!ab) 1481 return; 1482 if (!audit_rate_check()) { 1483 audit_log_lost("rate limit exceeded"); 1484 } else { 1485 struct nlmsghdr *nlh = nlmsg_hdr(ab->skb); 1486 nlh->nlmsg_len = ab->skb->len - NLMSG_SPACE(0); 1487 1488 if (audit_pid) { 1489 skb_queue_tail(&audit_skb_queue, ab->skb); 1490 wake_up_interruptible(&kauditd_wait); 1491 } else { 1492 audit_printk_skb(ab->skb); 1493 } 1494 ab->skb = NULL; 1495 } 1496 audit_buffer_free(ab); 1497 } 1498 1499 /** 1500 * audit_log - Log an audit record 1501 * @ctx: audit context 1502 * @gfp_mask: type of allocation 1503 * @type: audit message type 1504 * @fmt: format string to use 1505 * @...: variable parameters matching the format string 1506 * 1507 * This is a convenience function that calls audit_log_start, 1508 * audit_log_vformat, and audit_log_end. It may be called 1509 * in any context. 1510 */ 1511 void audit_log(struct audit_context *ctx, gfp_t gfp_mask, int type, 1512 const char *fmt, ...) 1513 { 1514 struct audit_buffer *ab; 1515 va_list args; 1516 1517 ab = audit_log_start(ctx, gfp_mask, type); 1518 if (ab) { 1519 va_start(args, fmt); 1520 audit_log_vformat(ab, fmt, args); 1521 va_end(args); 1522 audit_log_end(ab); 1523 } 1524 } 1525 1526 #ifdef CONFIG_SECURITY 1527 /** 1528 * audit_log_secctx - Converts and logs SELinux context 1529 * @ab: audit_buffer 1530 * @secid: security number 1531 * 1532 * This is a helper function that calls security_secid_to_secctx to convert 1533 * secid to secctx and then adds the (converted) SELinux context to the audit 1534 * log by calling audit_log_format, thus also preventing leak of internal secid 1535 * to userspace. If secid cannot be converted audit_panic is called. 1536 */ 1537 void audit_log_secctx(struct audit_buffer *ab, u32 secid) 1538 { 1539 u32 len; 1540 char *secctx; 1541 1542 if (security_secid_to_secctx(secid, &secctx, &len)) { 1543 audit_panic("Cannot convert secid to context"); 1544 } else { 1545 audit_log_format(ab, " obj=%s", secctx); 1546 security_release_secctx(secctx, len); 1547 } 1548 } 1549 EXPORT_SYMBOL(audit_log_secctx); 1550 #endif 1551 1552 EXPORT_SYMBOL(audit_log_start); 1553 EXPORT_SYMBOL(audit_log_end); 1554 EXPORT_SYMBOL(audit_log_format); 1555 EXPORT_SYMBOL(audit_log); 1556