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