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 Security Modules.
  25  *        2) Minimal run-time overhead:
  26  *           a) Minimal when syscall auditing is disabled (audit_enable=0).
  27  *           b) Small when syscall auditing is enabled and no audit record
  28  *              is generated (defer as much work as possible to record
  29  *              generation time):
  30  *              i) context is allocated,
  31  *              ii) names from getname are stored without a copy, and
  32  *              iii) inode information stored from path_lookup.
  33  *        3) Ability to disable syscall auditing at boot time (audit=0).
  34  *        4) Usable by other parts of the kernel (if audit_log* is called,
  35  *           then a syscall record will be generated automatically for the
  36  *           current syscall).
  37  *        5) Netlink interface to user-space.
  38  *        6) Support low-overhead kernel-based filtering to minimize the
  39  *           information that must be passed to user-space.
  40  *
  41  * Example user-space utilities: http://people.redhat.com/sgrubb/audit/
  42  */
  43
  44 #include <linux/init.h>
  45 #include <asm/types.h>
  46 #include <asm/atomic.h>
  47 #include <linux/mm.h>
  48 #include <linux/module.h>
  49 #include <linux/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/inotify.h>
  59 #include <linux/freezer.h>
  60 #include <linux/tty.h>
  61
  62 #include "audit.h"
  63
  64 /* No auditing will take place until audit_initialized != 0.
  65  * (Initialization happens after skb_init is called.) */
  66 static int      audit_initialized;
  67
  68 #define AUDIT_OFF       0
  69 #define AUDIT_ON        1
  70 #define AUDIT_LOCKED    2
  71 int             audit_enabled;
  72 int             audit_ever_enabled;
  73
  74 /* Default state when kernel boots without any parameters. */
  75 static int      audit_default;
  76
  77 /* If auditing cannot proceed, audit_failure selects what happens. */
  78 static int      audit_failure = AUDIT_FAIL_PRINTK;
  79
  80 /*
  81  * If audit records are to be written to the netlink socket, audit_pid
  82  * contains the pid of the auditd process and audit_nlk_pid contains
  83  * the pid to use to send netlink messages to that process.
  84  */
  85 int             audit_pid;
  86 static int      audit_nlk_pid;
  87
  88 /* If audit_rate_limit is non-zero, limit the rate of sending audit records
  89  * to that number per second.  This prevents DoS attacks, but results in
  90  * audit records being dropped. */
  91 static int      audit_rate_limit;
  92
  93 /* Number of outstanding audit_buffers allowed. */
  94 static int      audit_backlog_limit = 64;
  95 static int      audit_backlog_wait_time = 60 * HZ;
  96 static int      audit_backlog_wait_overflow = 0;
  97
  98 /* The identity of the user shutting down the audit system. */
  99 uid_t           audit_sig_uid = -1;
 100 pid_t           audit_sig_pid = -1;
 101 u32             audit_sig_sid = 0;
 102
 103 /* Records can be lost in several ways:
 104    0) [suppressed in audit_alloc]
 105    1) out of memory in audit_log_start [kmalloc of struct audit_buffer]
 106    2) out of memory in audit_log_move [alloc_skb]
 107    3) suppressed due to audit_rate_limit
 108    4) suppressed due to audit_backlog_limit
 109 */
 110 static atomic_t    audit_lost = ATOMIC_INIT(0);
 111
 112 /* The netlink socket. */
 113 static struct sock *audit_sock;
 114
 115 /* Inotify handle. */
 116 struct inotify_handle *audit_ih;
 117
 118 /* Hash for inode-based rules */
 119 struct list_head audit_inode_hash[AUDIT_INODE_BUCKETS];
 120
 121 /* The audit_freelist is a list of pre-allocated audit buffers (if more
 122  * than AUDIT_MAXFREE are in use, the audit buffer is freed instead of
 123  * being placed on the freelist). */
 124 static DEFINE_SPINLOCK(audit_freelist_lock);
 125 static int         audit_freelist_count;
 126 static LIST_HEAD(audit_freelist);
 127
 128 static struct sk_buff_head audit_skb_queue;
 129 static struct task_struct *kauditd_task;
 130 static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait);
 131 static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait);
 132
 133 /* Serialize requests from userspace. */
 134 static DEFINE_MUTEX(audit_cmd_mutex);
 135
 136 /* AUDIT_BUFSIZ is the size of the temporary buffer used for formatting
 137  * audit records.  Since printk uses a 1024 byte buffer, this buffer
 138  * should be at least that large. */
 139 #define AUDIT_BUFSIZ 1024
 140
 141 /* AUDIT_MAXFREE is the number of empty audit_buffers we keep on the
 142  * audit_freelist.  Doing so eliminates many kmalloc/kfree calls. */
 143 #define AUDIT_MAXFREE  (2*NR_CPUS)
 144
 145 /* The audit_buffer is used when formatting an audit record.  The caller
 146  * locks briefly to get the record off the freelist or to allocate the
 147  * buffer, and locks briefly to send the buffer to the netlink layer or
 148  * to place it on a transmit queue.  Multiple audit_buffers can be in
 149  * use simultaneously. */
 150 struct audit_buffer {
 151         struct list_head     list;
 152         struct sk_buff       *skb;      /* formatted skb ready to send */
 153         struct audit_context *ctx;      /* NULL or associated context */
 154         gfp_t                gfp_mask;
 155 };
 156
 157 static void audit_set_pid(struct audit_buffer *ab, pid_t pid)
 158 {
 159         if (ab) {
 160                 struct nlmsghdr *nlh = nlmsg_hdr(ab->skb);
 161                 nlh->nlmsg_pid = pid;
 162         }
 163 }
 164
 165 void audit_panic(const char *message)
 166 {
 167         switch (audit_failure)
 168         {
 169         case AUDIT_FAIL_SILENT:
 170                 break;
 171         case AUDIT_FAIL_PRINTK:
 172                 if (printk_ratelimit())
 173                         printk(KERN_ERR "audit: %s\n", message);
 174                 break;
 175         case AUDIT_FAIL_PANIC:
 176                 /* test audit_pid since printk is always losey, why bother? */
 177                 if (audit_pid)
 178                         panic("audit: %s\n", message);
 179                 break;
 180         }
 181 }
 182
 183 static inline int audit_rate_check(void)
 184 {
 185         static unsigned long    last_check = 0;
 186         static int              messages   = 0;
 187         static DEFINE_SPINLOCK(lock);
 188         unsigned long           flags;
 189         unsigned long           now;
 190         unsigned long           elapsed;
 191         int                     retval     = 0;
 192
 193         if (!audit_rate_limit) return 1;
 194
 195         spin_lock_irqsave(&lock, flags);
 196         if (++messages < audit_rate_limit) {
 197                 retval = 1;
 198         } else {
 199                 now     = jiffies;
 200                 elapsed = now - last_check;
 201                 if (elapsed > HZ) {
 202                         last_check = now;
 203                         messages   = 0;
 204                         retval     = 1;
 205                 }
 206         }
 207         spin_unlock_irqrestore(&lock, flags);
 208
 209         return retval;
 210 }
 211
 212 /**
 213  * audit_log_lost - conditionally log lost audit message event
 214  * @message: the message stating reason for lost audit message
 215  *
 216  * Emit at least 1 message per second, even if audit_rate_check is
 217  * throttling.
 218  * Always increment the lost messages counter.
 219 */
 220 void audit_log_lost(const char *message)
 221 {
 222         static unsigned long    last_msg = 0;
 223         static DEFINE_SPINLOCK(lock);
 224         unsigned long           flags;
 225         unsigned long           now;
 226         int                     print;
 227
 228         atomic_inc(&audit_lost);
 229
 230         print = (audit_failure == AUDIT_FAIL_PANIC || !audit_rate_limit);
 231
 232         if (!print) {
 233                 spin_lock_irqsave(&lock, flags);
 234                 now = jiffies;
 235                 if (now - last_msg > HZ) {
 236                         print = 1;
 237                         last_msg = now;
 238                 }
 239                 spin_unlock_irqrestore(&lock, flags);
 240         }
 241
 242         if (print) {
 243                 if (printk_ratelimit())
 244                         printk(KERN_WARNING
 245                                 "audit: audit_lost=%d audit_rate_limit=%d "
 246                                 "audit_backlog_limit=%d\n",
 247                                 atomic_read(&audit_lost),
 248                                 audit_rate_limit,
 249                                 audit_backlog_limit);
 250                 audit_panic(message);
 251         }
 252 }
 253
 254 static int audit_log_config_change(char *function_name, int new, int old,
 255                                    uid_t loginuid, u32 sid, int allow_changes)
 256 {
 257         struct audit_buffer *ab;
 258         int rc = 0;
 259
 260         ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
 261         audit_log_format(ab, "%s=%d old=%d by auid=%u", function_name, new,
 262                          old, loginuid);
 263         if (sid) {
 264                 char *ctx = NULL;
 265                 u32 len;
 266
 267                 rc = security_secid_to_secctx(sid, &ctx, &len);
 268                 if (rc) {
 269                         audit_log_format(ab, " sid=%u", sid);
 270                         allow_changes = 0; /* Something weird, deny request */
 271                 } else {
 272                         audit_log_format(ab, " subj=%s", ctx);
 273                         security_release_secctx(ctx, len);
 274                 }
 275         }
 276         audit_log_format(ab, " res=%d", allow_changes);
 277         audit_log_end(ab);
 278         return rc;
 279 }
 280
 281 static int audit_do_config_change(char *function_name, int *to_change,
 282                                   int new, uid_t loginuid, u32 sid)
 283 {
 284         int allow_changes, rc = 0, old = *to_change;
 285
 286         /* check if we are locked */
 287         if (audit_enabled == AUDIT_LOCKED)
 288                 allow_changes = 0;
 289         else
 290                 allow_changes = 1;
 291
 292         if (audit_enabled != AUDIT_OFF) {
 293                 rc = audit_log_config_change(function_name, new, old,
 294                                              loginuid, sid, allow_changes);
 295                 if (rc)
 296                         allow_changes = 0;
 297         }
 298
 299         /* If we are allowed, make the change */
 300         if (allow_changes == 1)
 301                 *to_change = new;
 302         /* Not allowed, update reason */
 303         else if (rc == 0)
 304                 rc = -EPERM;
 305         return rc;
 306 }
 307
 308 static int audit_set_rate_limit(int limit, uid_t loginuid, u32 sid)
 309 {
 310         return audit_do_config_change("audit_rate_limit", &audit_rate_limit,
 311                                       limit, loginuid, sid);
 312 }
 313
 314 static int audit_set_backlog_limit(int limit, uid_t loginuid, u32 sid)
 315 {
 316         return audit_do_config_change("audit_backlog_limit", &audit_backlog_limit,
 317                                       limit, loginuid, sid);
 318 }
 319
 320 static int audit_set_enabled(int state, uid_t loginuid, u32 sid)
 321 {
 322         int rc;
 323         if (state < AUDIT_OFF || state > AUDIT_LOCKED)
 324                 return -EINVAL;
 325
 326         rc =  audit_do_config_change("audit_enabled", &audit_enabled, state,
 327                                      loginuid, sid);
 328
 329         if (!rc)
 330                 audit_ever_enabled |= !!state;
 331
 332         return rc;
 333 }
 334
 335 static int audit_set_failure(int state, uid_t loginuid, u32 sid)
 336 {
 337         if (state != AUDIT_FAIL_SILENT
 338             && state != AUDIT_FAIL_PRINTK
 339             && state != AUDIT_FAIL_PANIC)
 340                 return -EINVAL;
 341
 342         return audit_do_config_change("audit_failure", &audit_failure, state,
 343                                       loginuid, sid);
 344 }
 345
 346 static int kauditd_thread(void *dummy)
 347 {
 348         struct sk_buff *skb;
 349
 350         set_freezable();
 351         while (!kthread_should_stop()) {
 352                 skb = skb_dequeue(&audit_skb_queue);
 353                 wake_up(&audit_backlog_wait);
 354                 if (skb) {
 355                         if (audit_pid) {
 356                                 int err = netlink_unicast(audit_sock, skb, audit_nlk_pid, 0);
 357                                 if (err < 0) {
 358                                         BUG_ON(err != -ECONNREFUSED); /* Shoudn't happen */
 359                                         printk(KERN_ERR "audit: *NO* daemon at audit_pid=%d\n", audit_pid);
 360                                         audit_log_lost("auditd dissapeared\n");
 361                                         audit_pid = 0;
 362                                 }
 363                         } else {
 364                                 if (printk_ratelimit())
 365                                         printk(KERN_NOTICE "%s\n", skb->data +
 366                                                 NLMSG_SPACE(0));
 367                                 else
 368                                         audit_log_lost("printk limit exceeded\n");
 369                                 kfree_skb(skb);
 370                         }
 371                 } else {
 372                         DECLARE_WAITQUEUE(wait, current);
 373                         set_current_state(TASK_INTERRUPTIBLE);
 374                         add_wait_queue(&kauditd_wait, &wait);
 375
 376                         if (!skb_queue_len(&audit_skb_queue)) {
 377                                 try_to_freeze();
 378                                 schedule();
 379                         }
 380
 381                         __set_current_state(TASK_RUNNING);
 382                         remove_wait_queue(&kauditd_wait, &wait);
 383                 }
 384         }
 385         return 0;
 386 }
 387
 388 static int audit_prepare_user_tty(pid_t pid, uid_t loginuid)
 389 {
 390         struct task_struct *tsk;
 391         int err;
 392
 393         read_lock(&tasklist_lock);
 394         tsk = find_task_by_pid(pid);
 395         err = -ESRCH;
 396         if (!tsk)
 397                 goto out;
 398         err = 0;
 399
 400         spin_lock_irq(&tsk->sighand->siglock);
 401         if (!tsk->signal->audit_tty)
 402                 err = -EPERM;
 403         spin_unlock_irq(&tsk->sighand->siglock);
 404         if (err)
 405                 goto out;
 406
 407         tty_audit_push_task(tsk, loginuid);
 408 out:
 409         read_unlock(&tasklist_lock);
 410         return err;
 411 }
 412
 413 int audit_send_list(void *_dest)
 414 {
 415         struct audit_netlink_list *dest = _dest;
 416         int pid = dest->pid;
 417         struct sk_buff *skb;
 418
 419         /* wait for parent to finish and send an ACK */
 420         mutex_lock(&audit_cmd_mutex);
 421         mutex_unlock(&audit_cmd_mutex);
 422
 423         while ((skb = __skb_dequeue(&dest->q)) != NULL)
 424                 netlink_unicast(audit_sock, skb, pid, 0);
 425
 426         kfree(dest);
 427
 428         return 0;
 429 }
 430
 431 #ifdef CONFIG_AUDIT_TREE
 432 static int prune_tree_thread(void *unused)
 433 {
 434         mutex_lock(&audit_cmd_mutex);
 435         audit_prune_trees();
 436         mutex_unlock(&audit_cmd_mutex);
 437         return 0;
 438 }
 439
 440 void audit_schedule_prune(void)
 441 {
 442         kthread_run(prune_tree_thread, NULL, "audit_prune_tree");
 443 }
 444 #endif
 445
 446 struct sk_buff *audit_make_reply(int pid, int seq, int type, int done,
 447                                  int multi, void *payload, int size)
 448 {
 449         struct sk_buff  *skb;
 450         struct nlmsghdr *nlh;
 451         int             len = NLMSG_SPACE(size);
 452         void            *data;
 453         int             flags = multi ? NLM_F_MULTI : 0;
 454         int             t     = done  ? NLMSG_DONE  : type;
 455
 456         skb = alloc_skb(len, GFP_KERNEL);
 457         if (!skb)
 458                 return NULL;
 459
 460         nlh              = NLMSG_PUT(skb, pid, seq, t, size);
 461         nlh->nlmsg_flags = flags;
 462         data             = NLMSG_DATA(nlh);
 463         memcpy(data, payload, size);
 464         return skb;
 465
 466 nlmsg_failure:                  /* Used by NLMSG_PUT */
 467         if (skb)
 468                 kfree_skb(skb);
 469         return NULL;
 470 }
 471
 472 /**
 473  * audit_send_reply - send an audit reply message via netlink
 474  * @pid: process id to send reply to
 475  * @seq: sequence number
 476  * @type: audit message type
 477  * @done: done (last) flag
 478  * @multi: multi-part message flag
 479  * @payload: payload data
 480  * @size: payload size
 481  *
 482  * Allocates an skb, builds the netlink message, and sends it to the pid.
 483  * No failure notifications.
 484  */
 485 void audit_send_reply(int pid, int seq, int type, int done, int multi,
 486                       void *payload, int size)
 487 {
 488         struct sk_buff  *skb;
 489         skb = audit_make_reply(pid, seq, type, done, multi, payload, size);
 490         if (!skb)
 491                 return;
 492         /* Ignore failure. It'll only happen if the sender goes away,
 493            because our timeout is set to infinite. */
 494         netlink_unicast(audit_sock, skb, pid, 0);
 495         return;
 496 }
 497
 498 /*
 499  * Check for appropriate CAP_AUDIT_ capabilities on incoming audit
 500  * control messages.
 501  */
 502 static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type)
 503 {
 504         int err = 0;
 505
 506         switch (msg_type) {
 507         case AUDIT_GET:
 508         case AUDIT_LIST:
 509         case AUDIT_LIST_RULES:
 510         case AUDIT_SET:
 511         case AUDIT_ADD:
 512         case AUDIT_ADD_RULE:
 513         case AUDIT_DEL:
 514         case AUDIT_DEL_RULE:
 515         case AUDIT_SIGNAL_INFO:
 516         case AUDIT_TTY_GET:
 517         case AUDIT_TTY_SET:
 518         case AUDIT_TRIM:
 519         case AUDIT_MAKE_EQUIV:
 520                 if (security_netlink_recv(skb, CAP_AUDIT_CONTROL))
 521                         err = -EPERM;
 522                 break;
 523         case AUDIT_USER:
 524         case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
 525         case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
 526                 if (security_netlink_recv(skb, CAP_AUDIT_WRITE))
 527                         err = -EPERM;
 528                 break;
 529         default:  /* bad msg */
 530                 err = -EINVAL;
 531         }
 532
 533         return err;
 534 }
 535
 536 static int audit_log_common_recv_msg(struct audit_buffer **ab, u16 msg_type,
 537                                      u32 pid, u32 uid, uid_t auid, u32 sid)
 538 {
 539         int rc = 0;
 540         char *ctx = NULL;
 541         u32 len;
 542
 543         if (!audit_enabled) {
 544                 *ab = NULL;
 545                 return rc;
 546         }
 547
 548         *ab = audit_log_start(NULL, GFP_KERNEL, msg_type);
 549         audit_log_format(*ab, "user pid=%d uid=%u auid=%u",
 550                          pid, uid, auid);
 551         if (sid) {
 552                 rc = security_secid_to_secctx(sid, &ctx, &len);
 553                 if (rc)
 554                         audit_log_format(*ab, " ssid=%u", sid);
 555                 else {
 556                         audit_log_format(*ab, " subj=%s", ctx);
 557                         security_release_secctx(ctx, len);
 558                 }
 559         }
 560
 561         return rc;
 562 }
 563
 564 static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 565 {
 566         u32                     uid, pid, seq, sid;
 567         void                    *data;
 568         struct audit_status     *status_get, status_set;
 569         int                     err;
 570         struct audit_buffer     *ab;
 571         u16                     msg_type = nlh->nlmsg_type;
 572         uid_t                   loginuid; /* loginuid of sender */
 573         struct audit_sig_info   *sig_data;
 574         char                    *ctx = NULL;
 575         u32                     len;
 576
 577         err = audit_netlink_ok(skb, msg_type);
 578         if (err)
 579                 return err;
 580
 581         /* As soon as there's any sign of userspace auditd,
 582          * start kauditd to talk to it */
 583         if (!kauditd_task)
 584                 kauditd_task = kthread_run(kauditd_thread, NULL, "kauditd");
 585         if (IS_ERR(kauditd_task)) {
 586                 err = PTR_ERR(kauditd_task);
 587                 kauditd_task = NULL;
 588                 return err;
 589         }
 590
 591         pid  = NETLINK_CREDS(skb)->pid;
 592         uid  = NETLINK_CREDS(skb)->uid;
 593         loginuid = NETLINK_CB(skb).loginuid;
 594         sid  = NETLINK_CB(skb).sid;
 595         seq  = nlh->nlmsg_seq;
 596         data = NLMSG_DATA(nlh);
 597
 598         switch (msg_type) {
 599         case AUDIT_GET:
 600                 status_set.enabled       = audit_enabled;
 601                 status_set.failure       = audit_failure;
 602                 status_set.pid           = audit_pid;
 603                 status_set.rate_limit    = audit_rate_limit;
 604                 status_set.backlog_limit = audit_backlog_limit;
 605                 status_set.lost          = atomic_read(&audit_lost);
 606                 status_set.backlog       = skb_queue_len(&audit_skb_queue);
 607                 audit_send_reply(NETLINK_CB(skb).pid, seq, AUDIT_GET, 0, 0,
 608                                  &status_set, sizeof(status_set));
 609                 break;
 610         case AUDIT_SET:
 611                 if (nlh->nlmsg_len < sizeof(struct audit_status))
 612                         return -EINVAL;
 613                 status_get   = (struct audit_status *)data;
 614                 if (status_get->mask & AUDIT_STATUS_ENABLED) {
 615                         err = audit_set_enabled(status_get->enabled,
 616                                                         loginuid, sid);
 617                         if (err < 0) return err;
 618                 }
 619                 if (status_get->mask & AUDIT_STATUS_FAILURE) {
 620                         err = audit_set_failure(status_get->failure,
 621                                                          loginuid, sid);
 622                         if (err < 0) return err;
 623                 }
 624                 if (status_get->mask & AUDIT_STATUS_PID) {
 625                         int new_pid = status_get->pid;
 626
 627                         if (audit_enabled != AUDIT_OFF)
 628                                 audit_log_config_change("audit_pid", new_pid,
 629                                                         audit_pid, loginuid,
 630                                                         sid, 1);
 631
 632                         audit_pid = new_pid;
 633                         audit_nlk_pid = NETLINK_CB(skb).pid;
 634                 }
 635                 if (status_get->mask & AUDIT_STATUS_RATE_LIMIT)
 636                         err = audit_set_rate_limit(status_get->rate_limit,
 637                                                          loginuid, sid);
 638                 if (status_get->mask & AUDIT_STATUS_BACKLOG_LIMIT)
 639                         err = audit_set_backlog_limit(status_get->backlog_limit,
 640                                                         loginuid, sid);
 641                 break;
 642         case AUDIT_USER:
 643         case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
 644         case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
 645                 if (!audit_enabled && msg_type != AUDIT_USER_AVC)
 646                         return 0;
 647
 648                 err = audit_filter_user(&NETLINK_CB(skb), msg_type);
 649                 if (err == 1) {
 650                         err = 0;
 651                         if (msg_type == AUDIT_USER_TTY) {
 652                                 err = audit_prepare_user_tty(pid, loginuid);
 653                                 if (err)
 654                                         break;
 655                         }
 656                         audit_log_common_recv_msg(&ab, msg_type, pid, uid,
 657                                                   loginuid, sid);
 658
 659                         if (msg_type != AUDIT_USER_TTY)
 660                                 audit_log_format(ab, " msg='%.1024s'",
 661                                                  (char *)data);
 662                         else {
 663                                 int size;
 664
 665                                 audit_log_format(ab, " msg=");
 666                                 size = nlmsg_len(nlh);
 667                                 audit_log_n_untrustedstring(ab, size,
 668                                                             data);
 669                         }
 670                         audit_set_pid(ab, pid);
 671                         audit_log_end(ab);
 672                 }
 673                 break;
 674         case AUDIT_ADD:
 675         case AUDIT_DEL:
 676                 if (nlmsg_len(nlh) < sizeof(struct audit_rule))
 677                         return -EINVAL;
 678                 if (audit_enabled == AUDIT_LOCKED) {
 679                         audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE, pid,
 680                                                   uid, loginuid, sid);
 681
 682                         audit_log_format(ab, " audit_enabled=%d res=0",
 683                                          audit_enabled);
 684                         audit_log_end(ab);
 685                         return -EPERM;
 686                 }
 687                 /* fallthrough */
 688         case AUDIT_LIST:
 689                 err = audit_receive_filter(nlh->nlmsg_type, NETLINK_CB(skb).pid,
 690                                            uid, seq, data, nlmsg_len(nlh),
 691                                            loginuid, sid);
 692                 break;
 693         case AUDIT_ADD_RULE:
 694         case AUDIT_DEL_RULE:
 695                 if (nlmsg_len(nlh) < sizeof(struct audit_rule_data))
 696                         return -EINVAL;
 697                 if (audit_enabled == AUDIT_LOCKED) {
 698                         audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE, pid,
 699                                                   uid, loginuid, sid);
 700
 701                         audit_log_format(ab, " audit_enabled=%d res=0",
 702                                          audit_enabled);
 703                         audit_log_end(ab);
 704                         return -EPERM;
 705                 }
 706                 /* fallthrough */
 707         case AUDIT_LIST_RULES:
 708                 err = audit_receive_filter(nlh->nlmsg_type, NETLINK_CB(skb).pid,
 709                                            uid, seq, data, nlmsg_len(nlh),
 710                                            loginuid, sid);
 711                 break;
 712         case AUDIT_TRIM:
 713                 audit_trim_trees();
 714
 715                 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE, pid,
 716                                           uid, loginuid, sid);
 717
 718                 audit_log_format(ab, " op=trim res=1");
 719                 audit_log_end(ab);
 720                 break;
 721         case AUDIT_MAKE_EQUIV: {
 722                 void *bufp = data;
 723                 u32 sizes[2];
 724                 size_t len = nlmsg_len(nlh);
 725                 char *old, *new;
 726
 727                 err = -EINVAL;
 728                 if (len < 2 * sizeof(u32))
 729                         break;
 730                 memcpy(sizes, bufp, 2 * sizeof(u32));
 731                 bufp += 2 * sizeof(u32);
 732                 len -= 2 * sizeof(u32);
 733                 old = audit_unpack_string(&bufp, &len, sizes[0]);
 734                 if (IS_ERR(old)) {
 735                         err = PTR_ERR(old);
 736                         break;
 737                 }
 738                 new = audit_unpack_string(&bufp, &len, sizes[1]);
 739                 if (IS_ERR(new)) {
 740                         err = PTR_ERR(new);
 741                         kfree(old);
 742                         break;
 743                 }
 744                 /* OK, here comes... */
 745                 err = audit_tag_tree(old, new);
 746
 747                 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE, pid,
 748                                           uid, loginuid, sid);
 749
 750                 audit_log_format(ab, " op=make_equiv old=");
 751                 audit_log_untrustedstring(ab, old);
 752                 audit_log_format(ab, " new=");
 753                 audit_log_untrustedstring(ab, new);
 754                 audit_log_format(ab, " res=%d", !err);
 755                 audit_log_end(ab);
 756                 kfree(old);
 757                 kfree(new);
 758                 break;
 759         }
 760         case AUDIT_SIGNAL_INFO:
 761                 err = security_secid_to_secctx(audit_sig_sid, &ctx, &len);
 762                 if (err)
 763                         return err;
 764                 sig_data = kmalloc(sizeof(*sig_data) + len, GFP_KERNEL);
 765                 if (!sig_data) {
 766                         security_release_secctx(ctx, len);
 767                         return -ENOMEM;
 768                 }
 769                 sig_data->uid = audit_sig_uid;
 770                 sig_data->pid = audit_sig_pid;
 771                 memcpy(sig_data->ctx, ctx, len);
 772                 security_release_secctx(ctx, len);
 773                 audit_send_reply(NETLINK_CB(skb).pid, seq, AUDIT_SIGNAL_INFO,
 774                                 0, 0, sig_data, sizeof(*sig_data) + len);
 775                 kfree(sig_data);
 776                 break;
 777         case AUDIT_TTY_GET: {
 778                 struct audit_tty_status s;
 779                 struct task_struct *tsk;
 780
 781                 read_lock(&tasklist_lock);
 782                 tsk = find_task_by_pid(pid);
 783                 if (!tsk)
 784                         err = -ESRCH;
 785                 else {
 786                         spin_lock_irq(&tsk->sighand->siglock);
 787                         s.enabled = tsk->signal->audit_tty != 0;
 788                         spin_unlock_irq(&tsk->sighand->siglock);
 789                 }
 790                 read_unlock(&tasklist_lock);
 791                 audit_send_reply(NETLINK_CB(skb).pid, seq, AUDIT_TTY_GET, 0, 0,
 792                                  &s, sizeof(s));
 793                 break;
 794         }
 795         case AUDIT_TTY_SET: {
 796                 struct audit_tty_status *s;
 797                 struct task_struct *tsk;
 798
 799                 if (nlh->nlmsg_len < sizeof(struct audit_tty_status))
 800                         return -EINVAL;
 801                 s = data;
 802                 if (s->enabled != 0 && s->enabled != 1)
 803                         return -EINVAL;
 804                 read_lock(&tasklist_lock);
 805                 tsk = find_task_by_pid(pid);
 806                 if (!tsk)
 807                         err = -ESRCH;
 808                 else {
 809                         spin_lock_irq(&tsk->sighand->siglock);
 810                         tsk->signal->audit_tty = s->enabled != 0;
 811                         spin_unlock_irq(&tsk->sighand->siglock);
 812                 }
 813                 read_unlock(&tasklist_lock);
 814                 break;
 815         }
 816         default:
 817                 err = -EINVAL;
 818                 break;
 819         }
 820
 821         return err < 0 ? err : 0;
 822 }
 823
 824 /*
 825  * Get message from skb (based on rtnetlink_rcv_skb).  Each message is
 826  * processed by audit_receive_msg.  Malformed skbs with wrong length are
 827  * discarded silently.
 828  */
 829 static void audit_receive_skb(struct sk_buff *skb)
 830 {
 831         int             err;
 832         struct nlmsghdr *nlh;
 833         u32             rlen;
 834
 835         while (skb->len >= NLMSG_SPACE(0)) {
 836                 nlh = nlmsg_hdr(skb);
 837                 if (nlh->nlmsg_len < sizeof(*nlh) || skb->len < nlh->nlmsg_len)
 838                         return;
 839                 rlen = NLMSG_ALIGN(nlh->nlmsg_len);
 840                 if (rlen > skb->len)
 841                         rlen = skb->len;
 842                 if ((err = audit_receive_msg(skb, nlh))) {
 843                         netlink_ack(skb, nlh, err);
 844                 } else if (nlh->nlmsg_flags & NLM_F_ACK)
 845                         netlink_ack(skb, nlh, 0);
 846                 skb_pull(skb, rlen);
 847         }
 848 }
 849
 850 /* Receive messages from netlink socket. */
 851 static void audit_receive(struct sk_buff  *skb)
 852 {
 853         mutex_lock(&audit_cmd_mutex);
 854         audit_receive_skb(skb);
 855         mutex_unlock(&audit_cmd_mutex);
 856 }
 857
 858 #ifdef CONFIG_AUDITSYSCALL
 859 static const struct inotify_operations audit_inotify_ops = {
 860         .handle_event   = audit_handle_ievent,
 861         .destroy_watch  = audit_free_parent,
 862 };
 863 #endif
 864
 865 /* Initialize audit support at boot time. */
 866 static int __init audit_init(void)
 867 {
 868         int i;
 869
 870         printk(KERN_INFO "audit: initializing netlink socket (%s)\n",
 871                audit_default ? "enabled" : "disabled");
 872         audit_sock = netlink_kernel_create(&init_net, NETLINK_AUDIT, 0,
 873                                            audit_receive, NULL, THIS_MODULE);
 874         if (!audit_sock)
 875                 audit_panic("cannot initialize netlink socket");
 876         else
 877                 audit_sock->sk_sndtimeo = MAX_SCHEDULE_TIMEOUT;
 878
 879         skb_queue_head_init(&audit_skb_queue);
 880         audit_initialized = 1;
 881         audit_enabled = audit_default;
 882         audit_ever_enabled |= !!audit_default;
 883
 884         audit_log(NULL, GFP_KERNEL, AUDIT_KERNEL, "initialized");
 885
 886 #ifdef CONFIG_AUDITSYSCALL
 887         audit_ih = inotify_init(&audit_inotify_ops);
 888         if (IS_ERR(audit_ih))
 889                 audit_panic("cannot initialize inotify handle");
 890 #endif
 891
 892         for (i = 0; i < AUDIT_INODE_BUCKETS; i++)
 893                 INIT_LIST_HEAD(&audit_inode_hash[i]);
 894
 895         return 0;
 896 }
 897 __initcall(audit_init);
 898
 899 /* Process kernel command-line parameter at boot time.  audit=0 or audit=1. */
 900 static int __init audit_enable(char *str)
 901 {
 902         audit_default = !!simple_strtol(str, NULL, 0);
 903         printk(KERN_INFO "audit: %s%s\n",
 904                audit_default ? "enabled" : "disabled",
 905                audit_initialized ? "" : " (after initialization)");
 906         if (audit_initialized) {
 907                 audit_enabled = audit_default;
 908                 audit_ever_enabled |= !!audit_default;
 909         }
 910         return 1;
 911 }
 912
 913 __setup("audit=", audit_enable);
 914
 915 static void audit_buffer_free(struct audit_buffer *ab)
 916 {
 917         unsigned long flags;
 918
 919         if (!ab)
 920                 return;
 921
 922         if (ab->skb)
 923                 kfree_skb(ab->skb);
 924
 925         spin_lock_irqsave(&audit_freelist_lock, flags);
 926         if (audit_freelist_count > AUDIT_MAXFREE)
 927                 kfree(ab);
 928         else {
 929                 audit_freelist_count++;
 930                 list_add(&ab->list, &audit_freelist);
 931         }
 932         spin_unlock_irqrestore(&audit_freelist_lock, flags);
 933 }
 934
 935 static struct audit_buffer * audit_buffer_alloc(struct audit_context *ctx,
 936                                                 gfp_t gfp_mask, int type)
 937 {
 938         unsigned long flags;
 939         struct audit_buffer *ab = NULL;
 940         struct nlmsghdr *nlh;
 941
 942         spin_lock_irqsave(&audit_freelist_lock, flags);
 943         if (!list_empty(&audit_freelist)) {
 944                 ab = list_entry(audit_freelist.next,
 945                                 struct audit_buffer, list);
 946                 list_del(&ab->list);
 947                 --audit_freelist_count;
 948         }
 949         spin_unlock_irqrestore(&audit_freelist_lock, flags);
 950
 951         if (!ab) {
 952                 ab = kmalloc(sizeof(*ab), gfp_mask);
 953                 if (!ab)
 954                         goto err;
 955         }
 956
 957         ab->skb = alloc_skb(AUDIT_BUFSIZ, gfp_mask);
 958         if (!ab->skb)
 959                 goto err;
 960
 961         ab->ctx = ctx;
 962         ab->gfp_mask = gfp_mask;
 963         nlh = (struct nlmsghdr *)skb_put(ab->skb, NLMSG_SPACE(0));
 964         nlh->nlmsg_type = type;
 965         nlh->nlmsg_flags = 0;
 966         nlh->nlmsg_pid = 0;
 967         nlh->nlmsg_seq = 0;
 968         return ab;
 969 err:
 970         audit_buffer_free(ab);
 971         return NULL;
 972 }
 973
 974 /**
 975  * audit_serial - compute a serial number for the audit record
 976  *
 977  * Compute a serial number for the audit record.  Audit records are
 978  * written to user-space as soon as they are generated, so a complete
 979  * audit record may be written in several pieces.  The timestamp of the
 980  * record and this serial number are used by the user-space tools to
 981  * determine which pieces belong to the same audit record.  The
 982  * (timestamp,serial) tuple is unique for each syscall and is live from
 983  * syscall entry to syscall exit.
 984  *
 985  * NOTE: Another possibility is to store the formatted records off the
 986  * audit context (for those records that have a context), and emit them
 987  * all at syscall exit.  However, this could delay the reporting of
 988  * significant errors until syscall exit (or never, if the system
 989  * halts).
 990  */
 991 unsigned int audit_serial(void)
 992 {
 993         static DEFINE_SPINLOCK(serial_lock);
 994         static unsigned int serial = 0;
 995
 996         unsigned long flags;
 997         unsigned int ret;
 998
 999         spin_lock_irqsave(&serial_lock, flags);
1000         do {
1001                 ret = ++serial;
1002         } while (unlikely(!ret));
1003         spin_unlock_irqrestore(&serial_lock, flags);
1004
1005         return ret;
1006 }
1007
1008 static inline void audit_get_stamp(struct audit_context *ctx,
1009                                    struct timespec *t, unsigned int *serial)
1010 {
1011         if (ctx)
1012                 auditsc_get_stamp(ctx, t, serial);
1013         else {
1014                 *t = CURRENT_TIME;
1015                 *serial = audit_serial();
1016         }
1017 }
1018
1019 /* Obtain an audit buffer.  This routine does locking to obtain the
1020  * audit buffer, but then no locking is required for calls to
1021  * audit_log_*format.  If the tsk is a task that is currently in a
1022  * syscall, then the syscall is marked as auditable and an audit record
1023  * will be written at syscall exit.  If there is no associated task, tsk
1024  * should be NULL. */
1025
1026 /**
1027  * audit_log_start - obtain an audit buffer
1028  * @ctx: audit_context (may be NULL)
1029  * @gfp_mask: type of allocation
1030  * @type: audit message type
1031  *
1032  * Returns audit_buffer pointer on success or NULL on error.
1033  *
1034  * Obtain an audit buffer.  This routine does locking to obtain the
1035  * audit buffer, but then no locking is required for calls to
1036  * audit_log_*format.  If the task (ctx) is a task that is currently in a
1037  * syscall, then the syscall is marked as auditable and an audit record
1038  * will be written at syscall exit.  If there is no associated task, then
1039  * task context (ctx) should be NULL.
1040  */
1041 struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
1042                                      int type)
1043 {
1044         struct audit_buffer     *ab     = NULL;
1045         struct timespec         t;
1046         unsigned int            uninitialized_var(serial);
1047         int reserve;
1048         unsigned long timeout_start = jiffies;
1049
1050         if (!audit_initialized)
1051                 return NULL;
1052
1053         if (unlikely(audit_filter_type(type)))
1054                 return NULL;
1055
1056         if (gfp_mask & __GFP_WAIT)
1057                 reserve = 0;
1058         else
1059                 reserve = 5; /* Allow atomic callers to go up to five
1060                                 entries over the normal backlog limit */
1061
1062         while (audit_backlog_limit
1063                && skb_queue_len(&audit_skb_queue) > audit_backlog_limit + reserve) {
1064                 if (gfp_mask & __GFP_WAIT && audit_backlog_wait_time
1065                     && time_before(jiffies, timeout_start + audit_backlog_wait_time)) {
1066
1067                         /* Wait for auditd to drain the queue a little */
1068                         DECLARE_WAITQUEUE(wait, current);
1069                         set_current_state(TASK_INTERRUPTIBLE);
1070                         add_wait_queue(&audit_backlog_wait, &wait);
1071
1072                         if (audit_backlog_limit &&
1073                             skb_queue_len(&audit_skb_queue) > audit_backlog_limit)
1074                                 schedule_timeout(timeout_start + audit_backlog_wait_time - jiffies);
1075
1076                         __set_current_state(TASK_RUNNING);
1077                         remove_wait_queue(&audit_backlog_wait, &wait);
1078                         continue;
1079                 }
1080                 if (audit_rate_check() && printk_ratelimit())
1081                         printk(KERN_WARNING
1082                                "audit: audit_backlog=%d > "
1083                                "audit_backlog_limit=%d\n",
1084                                skb_queue_len(&audit_skb_queue),
1085                                audit_backlog_limit);
1086                 audit_log_lost("backlog limit exceeded");
1087                 audit_backlog_wait_time = audit_backlog_wait_overflow;
1088                 wake_up(&audit_backlog_wait);
1089                 return NULL;
1090         }
1091
1092         ab = audit_buffer_alloc(ctx, gfp_mask, type);
1093         if (!ab) {
1094                 audit_log_lost("out of memory in audit_log_start");
1095                 return NULL;
1096         }
1097
1098         audit_get_stamp(ab->ctx, &t, &serial);
1099
1100         audit_log_format(ab, "audit(%lu.%03lu:%u): ",
1101                          t.tv_sec, t.tv_nsec/1000000, serial);
1102         return ab;
1103 }
1104
1105 /**
1106  * audit_expand - expand skb in the audit buffer
1107  * @ab: audit_buffer
1108  * @extra: space to add at tail of the skb
1109  *
1110  * Returns 0 (no space) on failed expansion, or available space if
1111  * successful.
1112  */
1113 static inline int audit_expand(struct audit_buffer *ab, int extra)
1114 {
1115         struct sk_buff *skb = ab->skb;
1116         int oldtail = skb_tailroom(skb);
1117         int ret = pskb_expand_head(skb, 0, extra, ab->gfp_mask);
1118         int newtail = skb_tailroom(skb);
1119
1120         if (ret < 0) {
1121                 audit_log_lost("out of memory in audit_expand");
1122                 return 0;
1123         }
1124
1125         skb->truesize += newtail - oldtail;
1126         return newtail;
1127 }
1128
1129 /*
1130  * Format an audit message into the audit buffer.  If there isn't enough
1131  * room in the audit buffer, more room will be allocated and vsnprint
1132  * will be called a second time.  Currently, we assume that a printk
1133  * can't format message larger than 1024 bytes, so we don't either.
1134  */
1135 static void audit_log_vformat(struct audit_buffer *ab, const char *fmt,
1136                               va_list args)
1137 {
1138         int len, avail;
1139         struct sk_buff *skb;
1140         va_list args2;
1141
1142         if (!ab)
1143                 return;
1144
1145         BUG_ON(!ab->skb);
1146         skb = ab->skb;
1147         avail = skb_tailroom(skb);
1148         if (avail == 0) {
1149                 avail = audit_expand(ab, AUDIT_BUFSIZ);
1150                 if (!avail)
1151                         goto out;
1152         }
1153         va_copy(args2, args);
1154         len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args);
1155         if (len >= avail) {
1156                 /* The printk buffer is 1024 bytes long, so if we get
1157                  * here and AUDIT_BUFSIZ is at least 1024, then we can
1158                  * log everything that printk could have logged. */
1159                 avail = audit_expand(ab,
1160                         max_t(unsigned, AUDIT_BUFSIZ, 1+len-avail));
1161                 if (!avail)
1162                         goto out;
1163                 len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args2);
1164         }
1165         va_end(args2);
1166         if (len > 0)
1167                 skb_put(skb, len);
1168 out:
1169         return;
1170 }
1171
1172 /**
1173  * audit_log_format - format a message into the audit buffer.
1174  * @ab: audit_buffer
1175  * @fmt: format string
1176  * @...: optional parameters matching @fmt string
1177  *
1178  * All the work is done in audit_log_vformat.
1179  */
1180 void audit_log_format(struct audit_buffer *ab, const char *fmt, ...)
1181 {
1182         va_list args;
1183
1184         if (!ab)
1185                 return;
1186         va_start(args, fmt);
1187         audit_log_vformat(ab, fmt, args);
1188         va_end(args);
1189 }
1190
1191 /**
1192  * audit_log_hex - convert a buffer to hex and append it to the audit skb
1193  * @ab: the audit_buffer
1194  * @buf: buffer to convert to hex
1195  * @len: length of @buf to be converted
1196  *
1197  * No return value; failure to expand is silently ignored.
1198  *
1199  * This function will take the passed buf and convert it into a string of
1200  * ascii hex digits. The new string is placed onto the skb.
1201  */
1202 void audit_log_hex(struct audit_buffer *ab, const unsigned char *buf,
1203                 size_t len)
1204 {
1205         int i, avail, new_len;
1206         unsigned char *ptr;
1207         struct sk_buff *skb;
1208         static const unsigned char *hex = "0123456789ABCDEF";
1209
1210         if (!ab)
1211                 return;
1212
1213         BUG_ON(!ab->skb);
1214         skb = ab->skb;
1215         avail = skb_tailroom(skb);
1216         new_len = len<<1;
1217         if (new_len >= avail) {
1218                 /* Round the buffer request up to the next multiple */
1219                 new_len = AUDIT_BUFSIZ*(((new_len-avail)/AUDIT_BUFSIZ) + 1);
1220                 avail = audit_expand(ab, new_len);
1221                 if (!avail)
1222                         return;
1223         }
1224
1225         ptr = skb_tail_pointer(skb);
1226         for (i=0; i<len; i++) {
1227                 *ptr++ = hex[(buf[i] & 0xF0)>>4]; /* Upper nibble */
1228                 *ptr++ = hex[buf[i] & 0x0F];      /* Lower nibble */
1229         }
1230         *ptr = 0;
1231         skb_put(skb, len << 1); /* new string is twice the old string */
1232 }
1233
1234 /*
1235  * Format a string of no more than slen characters into the audit buffer,
1236  * enclosed in quote marks.
1237  */
1238 static void audit_log_n_string(struct audit_buffer *ab, size_t slen,
1239                                const char *string)
1240 {
1241         int avail, new_len;
1242         unsigned char *ptr;
1243         struct sk_buff *skb;
1244
1245         if (!ab)
1246                 return;
1247
1248         BUG_ON(!ab->skb);
1249         skb = ab->skb;
1250         avail = skb_tailroom(skb);
1251         new_len = slen + 3;     /* enclosing quotes + null terminator */
1252         if (new_len > avail) {
1253                 avail = audit_expand(ab, new_len);
1254                 if (!avail)
1255                         return;
1256         }
1257         ptr = skb_tail_pointer(skb);
1258         *ptr++ = '"';
1259         memcpy(ptr, string, slen);
1260         ptr += slen;
1261         *ptr++ = '"';
1262         *ptr = 0;
1263         skb_put(skb, slen + 2); /* don't include null terminator */
1264 }
1265
1266 /**
1267  * audit_string_contains_control - does a string need to be logged in hex
1268  * @string: string to be checked
1269  * @len: max length of the string to check
1270  */
1271 int audit_string_contains_control(const char *string, size_t len)
1272 {
1273         const unsigned char *p;
1274         for (p = string; p < (const unsigned char *)string + len && *p; p++) {
1275                 if (*p == '"' || *p < 0x21 || *p > 0x7f)
1276                         return 1;
1277         }
1278         return 0;
1279 }
1280
1281 /**
1282  * audit_log_n_untrustedstring - log a string that may contain random characters
1283  * @ab: audit_buffer
1284  * @len: length of string (not including trailing null)
1285  * @string: string to be logged
1286  *
1287  * This code will escape a string that is passed to it if the string
1288  * contains a control character, unprintable character, double quote mark,
1289  * or a space. Unescaped strings will start and end with a double quote mark.
1290  * Strings that are escaped are printed in hex (2 digits per char).
1291  *
1292  * The caller specifies the number of characters in the string to log, which may
1293  * or may not be the entire string.
1294  */
1295 void audit_log_n_untrustedstring(struct audit_buffer *ab, size_t len,
1296                                  const char *string)
1297 {
1298         if (audit_string_contains_control(string, len))
1299                 audit_log_hex(ab, string, len);
1300         else
1301                 audit_log_n_string(ab, len, string);
1302 }
1303
1304 /**
1305  * audit_log_untrustedstring - log a string that may contain random characters
1306  * @ab: audit_buffer
1307  * @string: string to be logged
1308  *
1309  * Same as audit_log_n_untrustedstring(), except that strlen is used to
1310  * determine string length.
1311  */
1312 void audit_log_untrustedstring(struct audit_buffer *ab, const char *string)
1313 {
1314         audit_log_n_untrustedstring(ab, strlen(string), string);
1315 }
1316
1317 /* This is a helper-function to print the escaped d_path */
1318 void audit_log_d_path(struct audit_buffer *ab, const char *prefix,
1319                       struct path *path)
1320 {
1321         char *p, *pathname;
1322
1323         if (prefix)
1324                 audit_log_format(ab, " %s", prefix);
1325
1326         /* We will allow 11 spaces for ' (deleted)' to be appended */
1327         pathname = kmalloc(PATH_MAX+11, ab->gfp_mask);
1328         if (!pathname) {
1329                 audit_log_format(ab, "<no memory>");
1330                 return;
1331         }
1332         p = d_path(path, pathname, PATH_MAX+11);
1333         if (IS_ERR(p)) { /* Should never happen since we send PATH_MAX */
1334                 /* FIXME: can we save some information here? */
1335                 audit_log_format(ab, "<too long>");
1336         } else
1337                 audit_log_untrustedstring(ab, p);
1338         kfree(pathname);
1339 }
1340
1341 /**
1342  * audit_log_end - end one audit record
1343  * @ab: the audit_buffer
1344  *
1345  * The netlink_* functions cannot be called inside an irq context, so
1346  * the audit buffer is placed on a queue and a tasklet is scheduled to
1347  * remove them from the queue outside the irq context.  May be called in
1348  * any context.
1349  */
1350 void audit_log_end(struct audit_buffer *ab)
1351 {
1352         if (!ab)
1353                 return;
1354         if (!audit_rate_check()) {
1355                 audit_log_lost("rate limit exceeded");
1356         } else {
1357                 struct nlmsghdr *nlh = nlmsg_hdr(ab->skb);
1358                 if (audit_pid) {
1359                         nlh->nlmsg_len = ab->skb->len - NLMSG_SPACE(0);
1360                         skb_queue_tail(&audit_skb_queue, ab->skb);
1361                         ab->skb = NULL;
1362                         wake_up_interruptible(&kauditd_wait);
1363                 } else if (nlh->nlmsg_type != AUDIT_EOE) {
1364                         if (printk_ratelimit()) {
1365                                 printk(KERN_NOTICE "type=%d %s\n",
1366                                         nlh->nlmsg_type,
1367                                         ab->skb->data + NLMSG_SPACE(0));
1368                         } else
1369                                 audit_log_lost("printk limit exceeded\n");
1370                 }
1371         }
1372         audit_buffer_free(ab);
1373 }
1374
1375 /**
1376  * audit_log - Log an audit record
1377  * @ctx: audit context
1378  * @gfp_mask: type of allocation
1379  * @type: audit message type
1380  * @fmt: format string to use
1381  * @...: variable parameters matching the format string
1382  *
1383  * This is a convenience function that calls audit_log_start,
1384  * audit_log_vformat, and audit_log_end.  It may be called
1385  * in any context.
1386  */
1387 void audit_log(struct audit_context *ctx, gfp_t gfp_mask, int type,
1388                const char *fmt, ...)
1389 {
1390         struct audit_buffer *ab;
1391         va_list args;
1392
1393         ab = audit_log_start(ctx, gfp_mask, type);
1394         if (ab) {
1395                 va_start(args, fmt);
1396                 audit_log_vformat(ab, fmt, args);
1397                 va_end(args);
1398                 audit_log_end(ab);
1399         }
1400 }
1401
1402 EXPORT_SYMBOL(audit_log_start);
1403 EXPORT_SYMBOL(audit_log_end);
1404 EXPORT_SYMBOL(audit_log_format);
1405 EXPORT_SYMBOL(audit_log);