kernel/audit.c

   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 SELinux.
  25  *        2) Minimal run-time overhead:
  26  *           a) Minimal when syscall auditing is disabled (audit_enable=0).
  27  *           b) Small when syscall auditing is enabled and no audit record
  28  *              is generated (defer as much work as possible to record
  29  *              generation time):
  30  *              i) context is allocated,
  31  *              ii) names from getname are stored without a copy, and
  32  *              iii) inode information stored from path_lookup.
  33  *        3) Ability to disable syscall auditing at boot time (audit=0).
  34  *        4) Usable by other parts of the kernel (if audit_log* is called,
  35  *           then a syscall record will be generated automatically for the
  36  *           current syscall).
  37  *        5) Netlink interface to user-space.
  38  *        6) Support low-overhead kernel-based filtering to minimize the
  39  *           information that must be passed to user-space.
  40  *
  41  * Example user-space utilities: http://people.redhat.com/sgrubb/audit/
  42  */
  43
  44 #include <linux/init.h>
  45 #include <asm/types.h>
  46 #include <asm/atomic.h>
  47 #include <linux/mm.h>
  48 #include <linux/module.h>
  49 #include <linux/err.h>
  50 #include <linux/kthread.h>
  51
  52 #include <linux/audit.h>
  53
  54 #include <net/sock.h>
  55 #include <net/netlink.h>
  56 #include <linux/skbuff.h>
  57 #include <linux/netlink.h>
  58 #include <linux/selinux.h>
  59 #include <linux/inotify.h>
  60 #include <linux/freezer.h>
  61 #include <linux/tty.h>
  62
  63 #include "audit.h"
  64
  65 /* No auditing will take place until audit_initialized != 0.
  66  * (Initialization happens after skb_init is called.) */
  67 static int      audit_initialized;
  68
  69 #define AUDIT_OFF       0
  70 #define AUDIT_ON        1
  71 #define AUDIT_LOCKED    2
  72 int             audit_enabled;
  73 int             audit_ever_enabled;
  74
  75 /* Default state when kernel boots without any parameters. */
  76 static int      audit_default;
  77
  78 /* If auditing cannot proceed, audit_failure selects what happens. */
  79 static int      audit_failure = AUDIT_FAIL_PRINTK;
  80
  81 /* If audit records are to be written to the netlink socket, audit_pid
  82  * contains the (non-zero) pid. */
  83 int             audit_pid;
  84
  85 /* If audit_rate_limit is non-zero, limit the rate of sending audit records
  86  * to that number per second.  This prevents DoS attacks, but results in
  87  * audit records being dropped. */
  88 static int      audit_rate_limit;
  89
  90 /* Number of outstanding audit_buffers allowed. */
  91 static int      audit_backlog_limit = 64;
  92 static int      audit_backlog_wait_time = 60 * HZ;
  93 static int      audit_backlog_wait_overflow = 0;
  94
  95 /* The identity of the user shutting down the audit system. */
  96 uid_t           audit_sig_uid = -1;
  97 pid_t           audit_sig_pid = -1;
  98 u32             audit_sig_sid = 0;
  99
 100 /* Records can be lost in several ways:
 101    0) [suppressed in audit_alloc]
 102    1) out of memory in audit_log_start [kmalloc of struct audit_buffer]
 103    2) out of memory in audit_log_move [alloc_skb]
 104    3) suppressed due to audit_rate_limit
 105    4) suppressed due to audit_backlog_limit
 106 */
 107 static atomic_t    audit_lost = ATOMIC_INIT(0);
 108
 109 /* The netlink socket. */
 110 static struct sock *audit_sock;
 111
 112 /* Inotify handle. */
 113 struct inotify_handle *audit_ih;
 114
 115 /* Hash for inode-based rules */
 116 struct list_head audit_inode_hash[AUDIT_INODE_BUCKETS];
 117
 118 /* The audit_freelist is a list of pre-allocated audit buffers (if more
 119  * than AUDIT_MAXFREE are in use, the audit buffer is freed instead of
 120  * being placed on the freelist). */
 121 static DEFINE_SPINLOCK(audit_freelist_lock);
 122 static int         audit_freelist_count;
 123 static LIST_HEAD(audit_freelist);
 124
 125 static struct sk_buff_head audit_skb_queue;
 126 static struct task_struct *kauditd_task;
 127 static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait);
 128 static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait);
 129
 130 /* Serialize requests from userspace. */
 131 static DEFINE_MUTEX(audit_cmd_mutex);
 132
 133 /* AUDIT_BUFSIZ is the size of the temporary buffer used for formatting
 134  * audit records.  Since printk uses a 1024 byte buffer, this buffer
 135  * should be at least that large. */
 136 #define AUDIT_BUFSIZ 1024
 137
 138 /* AUDIT_MAXFREE is the number of empty audit_buffers we keep on the
 139  * audit_freelist.  Doing so eliminates many kmalloc/kfree calls. */
 140 #define AUDIT_MAXFREE  (2*NR_CPUS)
 141
 142 /* The audit_buffer is used when formatting an audit record.  The caller
 143  * locks briefly to get the record off the freelist or to allocate the
 144  * buffer, and locks briefly to send the buffer to the netlink layer or
 145  * to place it on a transmit queue.  Multiple audit_buffers can be in
 146  * use simultaneously. */
 147 struct audit_buffer {
 148         struct list_head     list;
 149         struct sk_buff       *skb;      /* formatted skb ready to send */
 150         struct audit_context *ctx;      /* NULL or associated context */
 151         gfp_t                gfp_mask;
 152 };
 153
 154 static void audit_set_pid(struct audit_buffer *ab, pid_t pid)
 155 {
 156         if (ab) {
 157                 struct nlmsghdr *nlh = nlmsg_hdr(ab->skb);
 158                 nlh->nlmsg_pid = pid;
 159         }
 160 }
 161
 162 void audit_panic(const char *message)
 163 {
 164         switch (audit_failure)
 165         {
 166         case AUDIT_FAIL_SILENT:
 167                 break;
 168         case AUDIT_FAIL_PRINTK:
 169                 if (printk_ratelimit())
 170                         printk(KERN_ERR "audit: %s\n", message);
 171                 break;
 172         case AUDIT_FAIL_PANIC:
 173                 panic("audit: %s\n", message);
 174                 break;
 175         }
 176 }
 177
 178 static inline int audit_rate_check(void)
 179 {
 180         static unsigned long    last_check = 0;
 181         static int              messages   = 0;
 182         static DEFINE_SPINLOCK(lock);
 183         unsigned long           flags;
 184         unsigned long           now;
 185         unsigned long           elapsed;
 186         int                     retval     = 0;
 187
 188         if (!audit_rate_limit) return 1;
 189
 190         spin_lock_irqsave(&lock, flags);
 191         if (++messages < audit_rate_limit) {
 192                 retval = 1;
 193         } else {
 194                 now     = jiffies;
 195                 elapsed = now - last_check;
 196                 if (elapsed > HZ) {
 197                         last_check = now;
 198                         messages   = 0;
 199                         retval     = 1;
 200                 }
 201         }
 202         spin_unlock_irqrestore(&lock, flags);
 203
 204         return retval;
 205 }
 206
 207 /**
 208  * audit_log_lost - conditionally log lost audit message event
 209  * @message: the message stating reason for lost audit message
 210  *
 211  * Emit at least 1 message per second, even if audit_rate_check is
 212  * throttling.
 213  * Always increment the lost messages counter.
 214 */
 215 void audit_log_lost(const char *message)
 216 {
 217         static unsigned long    last_msg = 0;
 218         static DEFINE_SPINLOCK(lock);
 219         unsigned long           flags;
 220         unsigned long           now;
 221         int                     print;
 222
 223         atomic_inc(&audit_lost);
 224
 225         print = (audit_failure == AUDIT_FAIL_PANIC || !audit_rate_limit);
 226
 227         if (!print) {
 228                 spin_lock_irqsave(&lock, flags);
 229                 now = jiffies;
 230                 if (now - last_msg > HZ) {
 231                         print = 1;
 232                         last_msg = now;
 233                 }
 234                 spin_unlock_irqrestore(&lock, flags);
 235         }
 236
 237         if (print) {
 238                 if (printk_ratelimit())
 239                         printk(KERN_WARNING
 240                                 "audit: audit_lost=%d audit_rate_limit=%d "
 241                                 "audit_backlog_limit=%d\n",
 242                                 atomic_read(&audit_lost),
 243                                 audit_rate_limit,
 244                                 audit_backlog_limit);
 245                 audit_panic(message);
 246         }
 247 }
 248
 249 static int audit_log_config_change(char *function_name, int new, int old,
 250                                    uid_t loginuid, u32 sid, int allow_changes)
 251 {
 252         struct audit_buffer *ab;
 253         int rc = 0;
 254
 255         ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
 256         audit_log_format(ab, "%s=%d old=%d by auid=%u", function_name, new,
 257                          old, loginuid);
 258         if (sid) {
 259                 char *ctx = NULL;
 260                 u32 len;
 261
 262                 rc = selinux_sid_to_string(sid, &ctx, &len);
 263                 if (rc) {
 264                         audit_log_format(ab, " sid=%u", sid);
 265                         allow_changes = 0; /* Something weird, deny request */
 266                 } else {
 267                         audit_log_format(ab, " subj=%s", ctx);
 268                         kfree(ctx);
 269                 }
 270         }
 271         audit_log_format(ab, " res=%d", allow_changes);
 272         audit_log_end(ab);
 273         return rc;
 274 }
 275
 276 static int audit_do_config_change(char *function_name, int *to_change,
 277                                   int new, uid_t loginuid, u32 sid)
 278 {
 279         int allow_changes, rc = 0, old = *to_change;
 280
 281         /* check if we are locked */
 282         if (audit_enabled == AUDIT_LOCKED)
 283                 allow_changes = 0;
 284         else
 285                 allow_changes = 1;
 286
 287         if (audit_enabled != AUDIT_OFF) {
 288                 rc = audit_log_config_change(function_name, new, old,
 289                                              loginuid, sid, allow_changes);
 290                 if (rc)
 291                         allow_changes = 0;
 292         }
 293
 294         /* If we are allowed, make the change */
 295         if (allow_changes == 1)
 296                 *to_change = new;
 297         /* Not allowed, update reason */
 298         else if (rc == 0)
 299                 rc = -EPERM;
 300         return rc;
 301 }
 302
 303 static int audit_set_rate_limit(int limit, uid_t loginuid, u32 sid)
 304 {
 305         return audit_do_config_change("audit_rate_limit", &audit_rate_limit,
 306                                       limit, loginuid, sid);
 307 }
 308
 309 static int audit_set_backlog_limit(int limit, uid_t loginuid, u32 sid)
 310 {
 311         return audit_do_config_change("audit_backlog_limit", &audit_backlog_limit,
 312                                       limit, loginuid, sid);
 313 }
 314
 315 static int audit_set_enabled(int state, uid_t loginuid, u32 sid)
 316 {
 317         int rc;
 318         if (state < AUDIT_OFF || state > AUDIT_LOCKED)
 319                 return -EINVAL;
 320
 321         rc =  audit_do_config_change("audit_enabled", &audit_enabled, state,
 322                                      loginuid, sid);
 323
 324         if (!rc)
 325                 audit_ever_enabled |= !!state;
 326
 327         return rc;
 328 }
 329
 330 static int audit_set_failure(int state, uid_t loginuid, u32 sid)
 331 {
 332         if (state != AUDIT_FAIL_SILENT
 333             && state != AUDIT_FAIL_PRINTK
 334             && state != AUDIT_FAIL_PANIC)
 335                 return -EINVAL;
 336
 337         return audit_do_config_change("audit_failure", &audit_failure, state,
 338                                       loginuid, sid);
 339 }
 340
 341 static int kauditd_thread(void *dummy)
 342 {
 343         struct sk_buff *skb;
 344
 345         set_freezable();
 346         while (!kthread_should_stop()) {
 347                 skb = skb_dequeue(&audit_skb_queue);
 348                 wake_up(&audit_backlog_wait);
 349                 if (skb) {
 350                         if (audit_pid) {
 351                                 int err = netlink_unicast(audit_sock, skb, audit_pid, 0);
 352                                 if (err < 0) {
 353                                         BUG_ON(err != -ECONNREFUSED); /* Shoudn't happen */
 354                                         printk(KERN_ERR "audit: *NO* daemon at audit_pid=%d\n", audit_pid);
 355                                         audit_pid = 0;
 356                                 }
 357                         } else {
 358                                 if (printk_ratelimit())
 359                                         printk(KERN_NOTICE "%s\n", skb->data +
 360                                                 NLMSG_SPACE(0));
 361                                 else
 362                                         audit_log_lost("printk limit exceeded\n");
 363                                 kfree_skb(skb);
 364                         }
 365                 } else {
 366                         DECLARE_WAITQUEUE(wait, current);
 367                         set_current_state(TASK_INTERRUPTIBLE);
 368                         add_wait_queue(&kauditd_wait, &wait);
 369
 370                         if (!skb_queue_len(&audit_skb_queue)) {
 371                                 try_to_freeze();
 372                                 schedule();
 373                         }
 374
 375                         __set_current_state(TASK_RUNNING);
 376                         remove_wait_queue(&kauditd_wait, &wait);
 377                 }
 378         }
 379         return 0;
 380 }
 381
 382 static int audit_prepare_user_tty(pid_t pid, uid_t loginuid)
 383 {
 384         struct task_struct *tsk;
 385         int err;
 386
 387         read_lock(&tasklist_lock);
 388         tsk = find_task_by_pid(pid);
 389         err = -ESRCH;
 390         if (!tsk)
 391                 goto out;
 392         err = 0;
 393
 394         spin_lock_irq(&tsk->sighand->siglock);
 395         if (!tsk->signal->audit_tty)
 396                 err = -EPERM;
 397         spin_unlock_irq(&tsk->sighand->siglock);
 398         if (err)
 399                 goto out;
 400
 401         tty_audit_push_task(tsk, loginuid);
 402 out:
 403         read_unlock(&tasklist_lock);
 404         return err;
 405 }
 406
 407 int audit_send_list(void *_dest)
 408 {
 409         struct audit_netlink_list *dest = _dest;
 410         int pid = dest->pid;
 411         struct sk_buff *skb;
 412
 413         /* wait for parent to finish and send an ACK */
 414         mutex_lock(&audit_cmd_mutex);
 415         mutex_unlock(&audit_cmd_mutex);
 416
 417         while ((skb = __skb_dequeue(&dest->q)) != NULL)
 418                 netlink_unicast(audit_sock, skb, pid, 0);
 419
 420         kfree(dest);
 421
 422         return 0;
 423 }
 424
 425 #ifdef CONFIG_AUDIT_TREE
 426 static int prune_tree_thread(void *unused)
 427 {
 428         mutex_lock(&audit_cmd_mutex);
 429         audit_prune_trees();
 430         mutex_unlock(&audit_cmd_mutex);
 431         return 0;
 432 }
 433
 434 void audit_schedule_prune(void)
 435 {
 436         kthread_run(prune_tree_thread, NULL, "audit_prune_tree");
 437 }
 438 #endif
 439
 440 struct sk_buff *audit_make_reply(int pid, int seq, int type, int done,
 441                                  int multi, void *payload, int size)
 442 {
 443         struct sk_buff  *skb;
 444         struct nlmsghdr *nlh;
 445         int             len = NLMSG_SPACE(size);
 446         void            *data;
 447         int             flags = multi ? NLM_F_MULTI : 0;
 448         int             t     = done  ? NLMSG_DONE  : type;
 449
 450         skb = alloc_skb(len, GFP_KERNEL);
 451         if (!skb)
 452                 return NULL;
 453
 454         nlh              = NLMSG_PUT(skb, pid, seq, t, size);
 455         nlh->nlmsg_flags = flags;
 456         data             = NLMSG_DATA(nlh);
 457         memcpy(data, payload, size);
 458         return skb;
 459
 460 nlmsg_failure:                  /* Used by NLMSG_PUT */
 461         if (skb)
 462                 kfree_skb(skb);
 463         return NULL;
 464 }
 465
 466 /**
 467  * audit_send_reply - send an audit reply message via netlink
 468  * @pid: process id to send reply to
 469  * @seq: sequence number
 470  * @type: audit message type
 471  * @done: done (last) flag
 472  * @multi: multi-part message flag
 473  * @payload: payload data
 474  * @size: payload size
 475  *
 476  * Allocates an skb, builds the netlink message, and sends it to the pid.
 477  * No failure notifications.
 478  */
 479 void audit_send_reply(int pid, int seq, int type, int done, int multi,
 480                       void *payload, int size)
 481 {
 482         struct sk_buff  *skb;
 483         skb = audit_make_reply(pid, seq, type, done, multi, payload, size);
 484         if (!skb)
 485                 return;
 486         /* Ignore failure. It'll only happen if the sender goes away,
 487            because our timeout is set to infinite. */
 488         netlink_unicast(audit_sock, skb, pid, 0);
 489         return;
 490 }
 491
 492 /*
 493  * Check for appropriate CAP_AUDIT_ capabilities on incoming audit
 494  * control messages.
 495  */
 496 static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type)
 497 {
 498         int err = 0;
 499
 500         switch (msg_type) {
 501         case AUDIT_GET:
 502         case AUDIT_LIST:
 503         case AUDIT_LIST_RULES:
 504         case AUDIT_SET:
 505         case AUDIT_ADD:
 506         case AUDIT_ADD_RULE:
 507         case AUDIT_DEL:
 508         case AUDIT_DEL_RULE:
 509         case AUDIT_SIGNAL_INFO:
 510         case AUDIT_TTY_GET:
 511         case AUDIT_TTY_SET:
 512         case AUDIT_TRIM:
 513         case AUDIT_MAKE_EQUIV:
 514                 if (security_netlink_recv(skb, CAP_AUDIT_CONTROL))
 515                         err = -EPERM;
 516                 break;
 517         case AUDIT_USER:
 518         case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
 519         case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
 520                 if (security_netlink_recv(skb, CAP_AUDIT_WRITE))
 521                         err = -EPERM;
 522                 break;
 523         default:  /* bad msg */
 524                 err = -EINVAL;
 525         }
 526
 527         return err;
 528 }
 529
 530 static int audit_log_common_recv_msg(struct audit_buffer **ab, u16 msg_type,
 531                                      u32 pid, u32 uid, uid_t auid, u32 sid)
 532 {
 533         int rc = 0;
 534         char *ctx = NULL;
 535         u32 len;
 536
 537         if (!audit_enabled) {
 538                 *ab = NULL;
 539                 return rc;
 540         }
 541
 542         *ab = audit_log_start(NULL, GFP_KERNEL, msg_type);
 543         audit_log_format(*ab, "user pid=%d uid=%u auid=%u",
 544                          pid, uid, auid);
 545         if (sid) {
 546                 rc = selinux_sid_to_string(sid, &ctx, &len);
 547                 if (rc)
 548                         audit_log_format(*ab, " ssid=%u", sid);
 549                 else
 550                         audit_log_format(*ab, " subj=%s", ctx);
 551                 kfree(ctx);
 552         }
 553
 554         return rc;
 555 }
 556
 557 static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 558 {
 559         u32                     uid, pid, seq, sid;
 560         void                    *data;
 561         struct audit_status     *status_get, status_set;
 562         int                     err;
 563         struct audit_buffer     *ab;
 564         u16                     msg_type = nlh->nlmsg_type;
 565         uid_t                   loginuid; /* loginuid of sender */
 566         struct audit_sig_info   *sig_data;
 567         char                    *ctx = NULL;
 568         u32                     len;
 569
 570         err = audit_netlink_ok(skb, msg_type);
 571         if (err)
 572                 return err;
 573
 574         /* As soon as there's any sign of userspace auditd,
 575          * start kauditd to talk to it */
 576         if (!kauditd_task)
 577                 kauditd_task = kthread_run(kauditd_thread, NULL, "kauditd");
 578         if (IS_ERR(kauditd_task)) {
 579                 err = PTR_ERR(kauditd_task);
 580                 kauditd_task = NULL;
 581                 return err;
 582         }
 583
 584         pid  = NETLINK_CREDS(skb)->pid;
 585         uid  = NETLINK_CREDS(skb)->uid;
 586         loginuid = NETLINK_CB(skb).loginuid;
 587         sid  = NETLINK_CB(skb).sid;
 588         seq  = nlh->nlmsg_seq;
 589         data = NLMSG_DATA(nlh);
 590
 591         switch (msg_type) {
 592         case AUDIT_GET:
 593                 status_set.enabled       = audit_enabled;
 594                 status_set.failure       = audit_failure;
 595                 status_set.pid           = audit_pid;
 596                 status_set.rate_limit    = audit_rate_limit;
 597                 status_set.backlog_limit = audit_backlog_limit;
 598                 status_set.lost          = atomic_read(&audit_lost);
 599                 status_set.backlog       = skb_queue_len(&audit_skb_queue);
 600                 audit_send_reply(NETLINK_CB(skb).pid, seq, AUDIT_GET, 0, 0,
 601                                  &status_set, sizeof(status_set));
 602                 break;
 603         case AUDIT_SET:
 604                 if (nlh->nlmsg_len < sizeof(struct audit_status))
 605                         return -EINVAL;
 606                 status_get   = (struct audit_status *)data;
 607                 if (status_get->mask & AUDIT_STATUS_ENABLED) {
 608                         err = audit_set_enabled(status_get->enabled,
 609                                                         loginuid, sid);
 610                         if (err < 0) return err;
 611                 }
 612                 if (status_get->mask & AUDIT_STATUS_FAILURE) {
 613                         err = audit_set_failure(status_get->failure,
 614                                                          loginuid, sid);
 615                         if (err < 0) return err;
 616                 }
 617                 if (status_get->mask & AUDIT_STATUS_PID) {
 618                         int new_pid = status_get->pid;
 619
 620                         if (audit_enabled != AUDIT_OFF)
 621                                 audit_log_config_change("audit_pid", new_pid,
 622                                                         audit_pid, loginuid,
 623                                                         sid, 1);
 624
 625                         audit_pid = new_pid;
 626                 }
 627                 if (status_get->mask & AUDIT_STATUS_RATE_LIMIT)
 628                         err = audit_set_rate_limit(status_get->rate_limit,
 629                                                          loginuid, sid);
 630                 if (status_get->mask & AUDIT_STATUS_BACKLOG_LIMIT)
 631                         err = audit_set_backlog_limit(status_get->backlog_limit,
 632                                                         loginuid, sid);
 633                 break;
 634         case AUDIT_USER:
 635         case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
 636         case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
 637                 if (!audit_enabled && msg_type != AUDIT_USER_AVC)
 638                         return 0;
 639
 640                 err = audit_filter_user(&NETLINK_CB(skb), msg_type);
 641                 if (err == 1) {
 642                         err = 0;
 643                         if (msg_type == AUDIT_USER_TTY) {
 644                                 err = audit_prepare_user_tty(pid, loginuid);
 645                                 if (err)
 646                                         break;
 647                         }
 648                         audit_log_common_recv_msg(&ab, msg_type, pid, uid,
 649                                                   loginuid, sid);
 650
 651                         if (msg_type != AUDIT_USER_TTY)
 652                                 audit_log_format(ab, " msg='%.1024s'",
 653                                                  (char *)data);
 654                         else {
 655                                 int size;
 656
 657                                 audit_log_format(ab, " msg=");
 658                                 size = nlmsg_len(nlh);
 659                                 audit_log_n_untrustedstring(ab, size,
 660                                                             data);
 661                         }
 662                         audit_set_pid(ab, pid);
 663                         audit_log_end(ab);
 664                 }
 665                 break;
 666         case AUDIT_ADD:
 667         case AUDIT_DEL:
 668                 if (nlmsg_len(nlh) < sizeof(struct audit_rule))
 669                         return -EINVAL;
 670                 if (audit_enabled == AUDIT_LOCKED) {
 671                         audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE, pid,
 672                                                   uid, loginuid, sid);
 673
 674                         audit_log_format(ab, " audit_enabled=%d res=0",
 675                                          audit_enabled);
 676                         audit_log_end(ab);
 677                         return -EPERM;
 678                 }
 679                 /* fallthrough */
 680         case AUDIT_LIST:
 681                 err = audit_receive_filter(nlh->nlmsg_type, NETLINK_CB(skb).pid,
 682                                            uid, seq, data, nlmsg_len(nlh),
 683                                            loginuid, sid);
 684                 break;
 685         case AUDIT_ADD_RULE:
 686         case AUDIT_DEL_RULE:
 687                 if (nlmsg_len(nlh) < sizeof(struct audit_rule_data))
 688                         return -EINVAL;
 689                 if (audit_enabled == AUDIT_LOCKED) {
 690                         audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE, pid,
 691                                                   uid, loginuid, sid);
 692
 693                         audit_log_format(ab, " audit_enabled=%d res=0",
 694                                          audit_enabled);
 695                         audit_log_end(ab);
 696                         return -EPERM;
 697                 }
 698                 /* fallthrough */
 699         case AUDIT_LIST_RULES:
 700                 err = audit_receive_filter(nlh->nlmsg_type, NETLINK_CB(skb).pid,
 701                                            uid, seq, data, nlmsg_len(nlh),
 702                                            loginuid, sid);
 703                 break;
 704         case AUDIT_TRIM:
 705                 audit_trim_trees();
 706
 707                 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE, pid,
 708                                           uid, loginuid, sid);
 709
 710                 audit_log_format(ab, " op=trim res=1");
 711                 audit_log_end(ab);
 712                 break;
 713         case AUDIT_MAKE_EQUIV: {
 714                 void *bufp = data;
 715                 u32 sizes[2];
 716                 size_t len = nlmsg_len(nlh);
 717                 char *old, *new;
 718
 719                 err = -EINVAL;
 720                 if (len < 2 * sizeof(u32))
 721                         break;
 722                 memcpy(sizes, bufp, 2 * sizeof(u32));
 723                 bufp += 2 * sizeof(u32);
 724                 len -= 2 * sizeof(u32);
 725                 old = audit_unpack_string(&bufp, &len, sizes[0]);
 726                 if (IS_ERR(old)) {
 727                         err = PTR_ERR(old);
 728                         break;
 729                 }
 730                 new = audit_unpack_string(&bufp, &len, sizes[1]);
 731                 if (IS_ERR(new)) {
 732                         err = PTR_ERR(new);
 733                         kfree(old);
 734                         break;
 735                 }
 736                 /* OK, here comes... */
 737                 err = audit_tag_tree(old, new);
 738
 739                 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE, pid,
 740                                           uid, loginuid, sid);
 741
 742                 audit_log_format(ab, " op=make_equiv old=");
 743                 audit_log_untrustedstring(ab, old);
 744                 audit_log_format(ab, " new=");
 745                 audit_log_untrustedstring(ab, new);
 746                 audit_log_format(ab, " res=%d", !err);
 747                 audit_log_end(ab);
 748                 kfree(old);
 749                 kfree(new);
 750                 break;
 751         }
 752         case AUDIT_SIGNAL_INFO:
 753                 err = selinux_sid_to_string(audit_sig_sid, &ctx, &len);
 754                 if (err)
 755                         return err;
 756                 sig_data = kmalloc(sizeof(*sig_data) + len, GFP_KERNEL);
 757                 if (!sig_data) {
 758                         kfree(ctx);
 759                         return -ENOMEM;
 760                 }
 761                 sig_data->uid = audit_sig_uid;
 762                 sig_data->pid = audit_sig_pid;
 763                 memcpy(sig_data->ctx, ctx, len);
 764                 kfree(ctx);
 765                 audit_send_reply(NETLINK_CB(skb).pid, seq, AUDIT_SIGNAL_INFO,
 766                                 0, 0, sig_data, sizeof(*sig_data) + len);
 767                 kfree(sig_data);
 768                 break;
 769         case AUDIT_TTY_GET: {
 770                 struct audit_tty_status s;
 771                 struct task_struct *tsk;
 772
 773                 read_lock(&tasklist_lock);
 774                 tsk = find_task_by_pid(pid);
 775                 if (!tsk)
 776                         err = -ESRCH;
 777                 else {
 778                         spin_lock_irq(&tsk->sighand->siglock);
 779                         s.enabled = tsk->signal->audit_tty != 0;
 780                         spin_unlock_irq(&tsk->sighand->siglock);
 781                 }
 782                 read_unlock(&tasklist_lock);
 783                 audit_send_reply(NETLINK_CB(skb).pid, seq, AUDIT_TTY_GET, 0, 0,
 784                                  &s, sizeof(s));
 785                 break;
 786         }
 787         case AUDIT_TTY_SET: {
 788                 struct audit_tty_status *s;
 789                 struct task_struct *tsk;
 790
 791                 if (nlh->nlmsg_len < sizeof(struct audit_tty_status))
 792                         return -EINVAL;
 793                 s = data;
 794                 if (s->enabled != 0 && s->enabled != 1)
 795                         return -EINVAL;
 796                 read_lock(&tasklist_lock);
 797                 tsk = find_task_by_pid(pid);
 798                 if (!tsk)
 799                         err = -ESRCH;
 800                 else {
 801                         spin_lock_irq(&tsk->sighand->siglock);
 802                         tsk->signal->audit_tty = s->enabled != 0;
 803                         spin_unlock_irq(&tsk->sighand->siglock);
 804                 }
 805                 read_unlock(&tasklist_lock);
 806                 break;
 807         }
 808         default:
 809                 err = -EINVAL;
 810                 break;
 811         }
 812
 813         return err < 0 ? err : 0;
 814 }
 815
 816 /*
 817  * Get message from skb (based on rtnetlink_rcv_skb).  Each message is
 818  * processed by audit_receive_msg.  Malformed skbs with wrong length are
 819  * discarded silently.
 820  */
 821 static void audit_receive_skb(struct sk_buff *skb)
 822 {
 823         int             err;
 824         struct nlmsghdr *nlh;
 825         u32             rlen;
 826
 827         while (skb->len >= NLMSG_SPACE(0)) {
 828                 nlh = nlmsg_hdr(skb);
 829                 if (nlh->nlmsg_len < sizeof(*nlh) || skb->len < nlh->nlmsg_len)
 830                         return;
 831                 rlen = NLMSG_ALIGN(nlh->nlmsg_len);
 832                 if (rlen > skb->len)
 833                         rlen = skb->len;
 834                 if ((err = audit_receive_msg(skb, nlh))) {
 835                         netlink_ack(skb, nlh, err);
 836                 } else if (nlh->nlmsg_flags & NLM_F_ACK)
 837                         netlink_ack(skb, nlh, 0);
 838                 skb_pull(skb, rlen);
 839         }
 840 }
 841
 842 /* Receive messages from netlink socket. */
 843 static void audit_receive(struct sk_buff  *skb)
 844 {
 845         mutex_lock(&audit_cmd_mutex);
 846         audit_receive_skb(skb);
 847         mutex_unlock(&audit_cmd_mutex);
 848 }
 849
 850 #ifdef CONFIG_AUDITSYSCALL
 851 static const struct inotify_operations audit_inotify_ops = {
 852         .handle_event   = audit_handle_ievent,
 853         .destroy_watch  = audit_free_parent,
 854 };
 855 #endif
 856
 857 /* Initialize audit support at boot time. */
 858 static int __init audit_init(void)
 859 {
 860         int i;
 861
 862         printk(KERN_INFO "audit: initializing netlink socket (%s)\n",
 863                audit_default ? "enabled" : "disabled");
 864         audit_sock = netlink_kernel_create(&init_net, NETLINK_AUDIT, 0,
 865                                            audit_receive, NULL, THIS_MODULE);
 866         if (!audit_sock)
 867                 audit_panic("cannot initialize netlink socket");
 868         else
 869                 audit_sock->sk_sndtimeo = MAX_SCHEDULE_TIMEOUT;
 870
 871         skb_queue_head_init(&audit_skb_queue);
 872         audit_initialized = 1;
 873         audit_enabled = audit_default;
 874         audit_ever_enabled |= !!audit_default;
 875
 876         /* Register the callback with selinux.  This callback will be invoked
 877          * when a new policy is loaded. */
 878         selinux_audit_set_callback(&selinux_audit_rule_update);
 879
 880         audit_log(NULL, GFP_KERNEL, AUDIT_KERNEL, "initialized");
 881
 882 #ifdef CONFIG_AUDITSYSCALL
 883         audit_ih = inotify_init(&audit_inotify_ops);
 884         if (IS_ERR(audit_ih))
 885                 audit_panic("cannot initialize inotify handle");
 886 #endif
 887
 888         for (i = 0; i < AUDIT_INODE_BUCKETS; i++)
 889                 INIT_LIST_HEAD(&audit_inode_hash[i]);
 890
 891         return 0;
 892 }
 893 __initcall(audit_init);
 894
 895 /* Process kernel command-line parameter at boot time.  audit=0 or audit=1. */
 896 static int __init audit_enable(char *str)
 897 {
 898         audit_default = !!simple_strtol(str, NULL, 0);
 899         printk(KERN_INFO "audit: %s%s\n",
 900                audit_default ? "enabled" : "disabled",
 901                audit_initialized ? "" : " (after initialization)");
 902         if (audit_initialized) {
 903                 audit_enabled = audit_default;
 904                 audit_ever_enabled |= !!audit_default;
 905         }
 906         return 1;
 907 }
 908
 909 __setup("audit=", audit_enable);
 910
 911 static void audit_buffer_free(struct audit_buffer *ab)
 912 {
 913         unsigned long flags;
 914
 915         if (!ab)
 916                 return;
 917
 918         if (ab->skb)
 919                 kfree_skb(ab->skb);
 920
 921         spin_lock_irqsave(&audit_freelist_lock, flags);
 922         if (audit_freelist_count > AUDIT_MAXFREE)
 923                 kfree(ab);
 924         else {
 925                 audit_freelist_count++;
 926                 list_add(&ab->list, &audit_freelist);
 927         }
 928         spin_unlock_irqrestore(&audit_freelist_lock, flags);
 929 }
 930
 931 static struct audit_buffer * audit_buffer_alloc(struct audit_context *ctx,
 932                                                 gfp_t gfp_mask, int type)
 933 {
 934         unsigned long flags;
 935         struct audit_buffer *ab = NULL;
 936         struct nlmsghdr *nlh;
 937
 938         spin_lock_irqsave(&audit_freelist_lock, flags);
 939         if (!list_empty(&audit_freelist)) {
 940                 ab = list_entry(audit_freelist.next,
 941                                 struct audit_buffer, list);
 942                 list_del(&ab->list);
 943                 --audit_freelist_count;
 944         }
 945         spin_unlock_irqrestore(&audit_freelist_lock, flags);
 946
 947         if (!ab) {
 948                 ab = kmalloc(sizeof(*ab), gfp_mask);
 949                 if (!ab)
 950                         goto err;
 951         }
 952
 953         ab->skb = alloc_skb(AUDIT_BUFSIZ, gfp_mask);
 954         if (!ab->skb)
 955                 goto err;
 956
 957         ab->ctx = ctx;
 958         ab->gfp_mask = gfp_mask;
 959         nlh = (struct nlmsghdr *)skb_put(ab->skb, NLMSG_SPACE(0));
 960         nlh->nlmsg_type = type;
 961         nlh->nlmsg_flags = 0;
 962         nlh->nlmsg_pid = 0;
 963         nlh->nlmsg_seq = 0;
 964         return ab;
 965 err:
 966         audit_buffer_free(ab);
 967         return NULL;
 968 }
 969
 970 /**
 971  * audit_serial - compute a serial number for the audit record
 972  *
 973  * Compute a serial number for the audit record.  Audit records are
 974  * written to user-space as soon as they are generated, so a complete
 975  * audit record may be written in several pieces.  The timestamp of the
 976  * record and this serial number are used by the user-space tools to
 977  * determine which pieces belong to the same audit record.  The
 978  * (timestamp,serial) tuple is unique for each syscall and is live from
 979  * syscall entry to syscall exit.
 980  *
 981  * NOTE: Another possibility is to store the formatted records off the
 982  * audit context (for those records that have a context), and emit them
 983  * all at syscall exit.  However, this could delay the reporting of
 984  * significant errors until syscall exit (or never, if the system
 985  * halts).
 986  */
 987 unsigned int audit_serial(void)
 988 {
 989         static DEFINE_SPINLOCK(serial_lock);
 990         static unsigned int serial = 0;
 991
 992         unsigned long flags;
 993         unsigned int ret;
 994
 995         spin_lock_irqsave(&serial_lock, flags);
 996         do {
 997                 ret = ++serial;
 998         } while (unlikely(!ret));
 999         spin_unlock_irqrestore(&serial_lock, flags);
1000
1001         return ret;
1002 }
1003
1004 static inline void audit_get_stamp(struct audit_context *ctx,
1005                                    struct timespec *t, unsigned int *serial)
1006 {
1007         if (ctx)
1008                 auditsc_get_stamp(ctx, t, serial);
1009         else {
1010                 *t = CURRENT_TIME;
1011                 *serial = audit_serial();
1012         }
1013 }
1014
1015 /* Obtain an audit buffer.  This routine does locking to obtain the
1016  * audit buffer, but then no locking is required for calls to
1017  * audit_log_*format.  If the tsk is a task that is currently in a
1018  * syscall, then the syscall is marked as auditable and an audit record
1019  * will be written at syscall exit.  If there is no associated task, tsk
1020  * should be NULL. */
1021
1022 /**
1023  * audit_log_start - obtain an audit buffer
1024  * @ctx: audit_context (may be NULL)
1025  * @gfp_mask: type of allocation
1026  * @type: audit message type
1027  *
1028  * Returns audit_buffer pointer on success or NULL on error.
1029  *
1030  * Obtain an audit buffer.  This routine does locking to obtain the
1031  * audit buffer, but then no locking is required for calls to
1032  * audit_log_*format.  If the task (ctx) is a task that is currently in a
1033  * syscall, then the syscall is marked as auditable and an audit record
1034  * will be written at syscall exit.  If there is no associated task, then
1035  * task context (ctx) should be NULL.
1036  */
1037 struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
1038                                      int type)
1039 {
1040         struct audit_buffer     *ab     = NULL;
1041         struct timespec         t;
1042         unsigned int            uninitialized_var(serial);
1043         int reserve;
1044         unsigned long timeout_start = jiffies;
1045
1046         if (!audit_initialized)
1047                 return NULL;
1048
1049         if (unlikely(audit_filter_type(type)))
1050                 return NULL;
1051
1052         if (gfp_mask & __GFP_WAIT)
1053                 reserve = 0;
1054         else
1055                 reserve = 5; /* Allow atomic callers to go up to five
1056                                 entries over the normal backlog limit */
1057
1058         while (audit_backlog_limit
1059                && skb_queue_len(&audit_skb_queue) > audit_backlog_limit + reserve) {
1060                 if (gfp_mask & __GFP_WAIT && audit_backlog_wait_time
1061                     && time_before(jiffies, timeout_start + audit_backlog_wait_time)) {
1062
1063                         /* Wait for auditd to drain the queue a little */
1064                         DECLARE_WAITQUEUE(wait, current);
1065                         set_current_state(TASK_INTERRUPTIBLE);
1066                         add_wait_queue(&audit_backlog_wait, &wait);
1067
1068                         if (audit_backlog_limit &&
1069                             skb_queue_len(&audit_skb_queue) > audit_backlog_limit)
1070                                 schedule_timeout(timeout_start + audit_backlog_wait_time - jiffies);
1071
1072                         __set_current_state(TASK_RUNNING);
1073                         remove_wait_queue(&audit_backlog_wait, &wait);
1074                         continue;
1075                 }
1076                 if (audit_rate_check() && printk_ratelimit())
1077                         printk(KERN_WARNING
1078                                "audit: audit_backlog=%d > "
1079                                "audit_backlog_limit=%d\n",
1080                                skb_queue_len(&audit_skb_queue),
1081                                audit_backlog_limit);
1082                 audit_log_lost("backlog limit exceeded");
1083                 audit_backlog_wait_time = audit_backlog_wait_overflow;
1084                 wake_up(&audit_backlog_wait);
1085                 return NULL;
1086         }
1087
1088         ab = audit_buffer_alloc(ctx, gfp_mask, type);
1089         if (!ab) {
1090                 audit_log_lost("out of memory in audit_log_start");
1091                 return NULL;
1092         }
1093
1094         audit_get_stamp(ab->ctx, &t, &serial);
1095
1096         audit_log_format(ab, "audit(%lu.%03lu:%u): ",
1097                          t.tv_sec, t.tv_nsec/1000000, serial);
1098         return ab;
1099 }
1100
1101 /**
1102  * audit_expand - expand skb in the audit buffer
1103  * @ab: audit_buffer
1104  * @extra: space to add at tail of the skb
1105  *
1106  * Returns 0 (no space) on failed expansion, or available space if
1107  * successful.
1108  */
1109 static inline int audit_expand(struct audit_buffer *ab, int extra)
1110 {
1111         struct sk_buff *skb = ab->skb;
1112         int oldtail = skb_tailroom(skb);
1113         int ret = pskb_expand_head(skb, 0, extra, ab->gfp_mask);
1114         int newtail = skb_tailroom(skb);
1115
1116         if (ret < 0) {
1117                 audit_log_lost("out of memory in audit_expand");
1118                 return 0;
1119         }
1120
1121         skb->truesize += newtail - oldtail;
1122         return newtail;
1123 }
1124
1125 /*
1126  * Format an audit message into the audit buffer.  If there isn't enough
1127  * room in the audit buffer, more room will be allocated and vsnprint
1128  * will be called a second time.  Currently, we assume that a printk
1129  * can't format message larger than 1024 bytes, so we don't either.
1130  */
1131 static void audit_log_vformat(struct audit_buffer *ab, const char *fmt,
1132                               va_list args)
1133 {
1134         int len, avail;
1135         struct sk_buff *skb;
1136         va_list args2;
1137
1138         if (!ab)
1139                 return;
1140
1141         BUG_ON(!ab->skb);
1142         skb = ab->skb;
1143         avail = skb_tailroom(skb);
1144         if (avail == 0) {
1145                 avail = audit_expand(ab, AUDIT_BUFSIZ);
1146                 if (!avail)
1147                         goto out;
1148         }
1149         va_copy(args2, args);
1150         len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args);
1151         if (len >= avail) {
1152                 /* The printk buffer is 1024 bytes long, so if we get
1153                  * here and AUDIT_BUFSIZ is at least 1024, then we can
1154                  * log everything that printk could have logged. */
1155                 avail = audit_expand(ab,
1156                         max_t(unsigned, AUDIT_BUFSIZ, 1+len-avail));
1157                 if (!avail)
1158                         goto out;
1159                 len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args2);
1160         }
1161         va_end(args2);
1162         if (len > 0)
1163                 skb_put(skb, len);
1164 out:
1165         return;
1166 }
1167
1168 /**
1169  * audit_log_format - format a message into the audit buffer.
1170  * @ab: audit_buffer
1171  * @fmt: format string
1172  * @...: optional parameters matching @fmt string
1173  *
1174  * All the work is done in audit_log_vformat.
1175  */
1176 void audit_log_format(struct audit_buffer *ab, const char *fmt, ...)
1177 {
1178         va_list args;
1179
1180         if (!ab)
1181                 return;
1182         va_start(args, fmt);
1183         audit_log_vformat(ab, fmt, args);
1184         va_end(args);
1185 }
1186
1187 /**
1188  * audit_log_hex - convert a buffer to hex and append it to the audit skb
1189  * @ab: the audit_buffer
1190  * @buf: buffer to convert to hex
1191  * @len: length of @buf to be converted
1192  *
1193  * No return value; failure to expand is silently ignored.
1194  *
1195  * This function will take the passed buf and convert it into a string of
1196  * ascii hex digits. The new string is placed onto the skb.
1197  */
1198 void audit_log_hex(struct audit_buffer *ab, const unsigned char *buf,
1199                 size_t len)
1200 {
1201         int i, avail, new_len;
1202         unsigned char *ptr;
1203         struct sk_buff *skb;
1204         static const unsigned char *hex = "0123456789ABCDEF";
1205
1206         if (!ab)
1207                 return;
1208
1209         BUG_ON(!ab->skb);
1210         skb = ab->skb;
1211         avail = skb_tailroom(skb);
1212         new_len = len<<1;
1213         if (new_len >= avail) {
1214                 /* Round the buffer request up to the next multiple */
1215                 new_len = AUDIT_BUFSIZ*(((new_len-avail)/AUDIT_BUFSIZ) + 1);
1216                 avail = audit_expand(ab, new_len);
1217                 if (!avail)
1218                         return;
1219         }
1220
1221         ptr = skb_tail_pointer(skb);
1222         for (i=0; i<len; i++) {
1223                 *ptr++ = hex[(buf[i] & 0xF0)>>4]; /* Upper nibble */
1224                 *ptr++ = hex[buf[i] & 0x0F];      /* Lower nibble */
1225         }
1226         *ptr = 0;
1227         skb_put(skb, len << 1); /* new string is twice the old string */
1228 }
1229
1230 /*
1231  * Format a string of no more than slen characters into the audit buffer,
1232  * enclosed in quote marks.
1233  */
1234 static void audit_log_n_string(struct audit_buffer *ab, size_t slen,
1235                                const char *string)
1236 {
1237         int avail, new_len;
1238         unsigned char *ptr;
1239         struct sk_buff *skb;
1240
1241         if (!ab)
1242                 return;
1243
1244         BUG_ON(!ab->skb);
1245         skb = ab->skb;
1246         avail = skb_tailroom(skb);
1247         new_len = slen + 3;     /* enclosing quotes + null terminator */
1248         if (new_len > avail) {
1249                 avail = audit_expand(ab, new_len);
1250                 if (!avail)
1251                         return;
1252         }
1253         ptr = skb_tail_pointer(skb);
1254         *ptr++ = '"';
1255         memcpy(ptr, string, slen);
1256         ptr += slen;
1257         *ptr++ = '"';
1258         *ptr = 0;
1259         skb_put(skb, slen + 2); /* don't include null terminator */
1260 }
1261
1262 /**
1263  * audit_string_contains_control - does a string need to be logged in hex
1264  * @string - string to be checked
1265  * @len - max length of the string to check
1266  */
1267 int audit_string_contains_control(const char *string, size_t len)
1268 {
1269         const unsigned char *p;
1270         for (p = string; p < (const unsigned char *)string + len && *p; p++) {
1271                 if (*p == '"' || *p < 0x21 || *p > 0x7f)
1272                         return 1;
1273         }
1274         return 0;
1275 }
1276
1277 /**
1278  * audit_log_n_untrustedstring - log a string that may contain random characters
1279  * @ab: audit_buffer
1280  * @len: lenth of string (not including trailing null)
1281  * @string: string to be logged
1282  *
1283  * This code will escape a string that is passed to it if the string
1284  * contains a control character, unprintable character, double quote mark,
1285  * or a space. Unescaped strings will start and end with a double quote mark.
1286  * Strings that are escaped are printed in hex (2 digits per char).
1287  *
1288  * The caller specifies the number of characters in the string to log, which may
1289  * or may not be the entire string.
1290  */
1291 void audit_log_n_untrustedstring(struct audit_buffer *ab, size_t len,
1292                                  const char *string)
1293 {
1294         if (audit_string_contains_control(string, len))
1295                 audit_log_hex(ab, string, len);
1296         else
1297                 audit_log_n_string(ab, len, string);
1298 }
1299
1300 /**
1301  * audit_log_untrustedstring - log a string that may contain random characters
1302  * @ab: audit_buffer
1303  * @string: string to be logged
1304  *
1305  * Same as audit_log_n_untrustedstring(), except that strlen is used to
1306  * determine string length.
1307  */
1308 void audit_log_untrustedstring(struct audit_buffer *ab, const char *string)
1309 {
1310         audit_log_n_untrustedstring(ab, strlen(string), string);
1311 }
1312
1313 /* This is a helper-function to print the escaped d_path */
1314 void audit_log_d_path(struct audit_buffer *ab, const char *prefix,
1315                       struct dentry *dentry, struct vfsmount *vfsmnt)
1316 {
1317         char *p, *path;
1318
1319         if (prefix)
1320                 audit_log_format(ab, " %s", prefix);
1321
1322         /* We will allow 11 spaces for ' (deleted)' to be appended */
1323         path = kmalloc(PATH_MAX+11, ab->gfp_mask);
1324         if (!path) {
1325                 audit_log_format(ab, "<no memory>");
1326                 return;
1327         }
1328         p = d_path(dentry, vfsmnt, path, PATH_MAX+11);
1329         if (IS_ERR(p)) { /* Should never happen since we send PATH_MAX */
1330                 /* FIXME: can we save some information here? */
1331                 audit_log_format(ab, "<too long>");
1332         } else
1333                 audit_log_untrustedstring(ab, p);
1334         kfree(path);
1335 }
1336
1337 /**
1338  * audit_log_end - end one audit record
1339  * @ab: the audit_buffer
1340  *
1341  * The netlink_* functions cannot be called inside an irq context, so
1342  * the audit buffer is placed on a queue and a tasklet is scheduled to
1343  * remove them from the queue outside the irq context.  May be called in
1344  * any context.
1345  */
1346 void audit_log_end(struct audit_buffer *ab)
1347 {
1348         if (!ab)
1349                 return;
1350         if (!audit_rate_check()) {
1351                 audit_log_lost("rate limit exceeded");
1352         } else {
1353                 if (audit_pid) {
1354                         struct nlmsghdr *nlh = nlmsg_hdr(ab->skb);
1355                         nlh->nlmsg_len = ab->skb->len - NLMSG_SPACE(0);
1356                         skb_queue_tail(&audit_skb_queue, ab->skb);
1357                         ab->skb = NULL;
1358                         wake_up_interruptible(&kauditd_wait);
1359                 } else if (printk_ratelimit()) {
1360                         struct nlmsghdr *nlh = nlmsg_hdr(ab->skb);
1361                         printk(KERN_NOTICE "type=%d %s\n", nlh->nlmsg_type, ab->skb->data + NLMSG_SPACE(0));
1362                 } else {
1363                         audit_log_lost("printk limit exceeded\n");
1364                 }
1365         }
1366         audit_buffer_free(ab);
1367 }
1368
1369 /**
1370  * audit_log - Log an audit record
1371  * @ctx: audit context
1372  * @gfp_mask: type of allocation
1373  * @type: audit message type
1374  * @fmt: format string to use
1375  * @...: variable parameters matching the format string
1376  *
1377  * This is a convenience function that calls audit_log_start,
1378  * audit_log_vformat, and audit_log_end.  It may be called
1379  * in any context.
1380  */
1381 void audit_log(struct audit_context *ctx, gfp_t gfp_mask, int type,
1382                const char *fmt, ...)
1383 {
1384         struct audit_buffer *ab;
1385         va_list args;
1386
1387         ab = audit_log_start(ctx, gfp_mask, type);
1388         if (ab) {
1389                 va_start(args, fmt);
1390                 audit_log_vformat(ab, fmt, args);
1391                 va_end(args);
1392                 audit_log_end(ab);
1393         }
1394 }
1395
1396 EXPORT_SYMBOL(audit_log_start);
1397 EXPORT_SYMBOL(audit_log_end);
1398 EXPORT_SYMBOL(audit_log_format);
1399 EXPORT_SYMBOL(audit_log);