linux/kernel/audit.c
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   1/* audit.c -- Auditing support
   2 * Gateway between the kernel (e.g., selinux) and the user-space audit daemon.
   3 * System-call specific features have moved to auditsc.c
   4 *
   5 * Copyright 2003-2007 Red Hat Inc., Durham, North Carolina.
   6 * All Rights Reserved.
   7 *
   8 * This program is free software; you can redistribute it and/or modify
   9 * it under the terms of the GNU General Public License as published by
  10 * the Free Software Foundation; either version 2 of the License, or
  11 * (at your option) any later version.
  12 *
  13 * This program is distributed in the hope that it will be useful,
  14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 * GNU General Public License for more details.
  17 *
  18 * You should have received a copy of the GNU General Public License
  19 * along with this program; if not, write to the Free Software
  20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  21 *
  22 * Written by Rickard E. (Rik) Faith <faith@redhat.com>
  23 *
  24 * Goals: 1) Integrate fully with Security Modules.
  25 *        2) Minimal run-time overhead:
  26 *           a) Minimal when syscall auditing is disabled (audit_enable=0).
  27 *           b) Small when syscall auditing is enabled and no audit record
  28 *              is generated (defer as much work as possible to record
  29 *              generation time):
  30 *              i) context is allocated,
  31 *              ii) names from getname are stored without a copy, and
  32 *              iii) inode information stored from path_lookup.
  33 *        3) Ability to disable syscall auditing at boot time (audit=0).
  34 *        4) Usable by other parts of the kernel (if audit_log* is called,
  35 *           then a syscall record will be generated automatically for the
  36 *           current syscall).
  37 *        5) Netlink interface to user-space.
  38 *        6) Support low-overhead kernel-based filtering to minimize the
  39 *           information that must be passed to user-space.
  40 *
  41 * Example user-space utilities: http://people.redhat.com/sgrubb/audit/
  42 */
  43
  44#include <linux/init.h>
  45#include <asm/types.h>
  46#include <linux/atomic.h>
  47#include <linux/mm.h>
  48#include <linux/export.h>
  49#include <linux/slab.h>
  50#include <linux/err.h>
  51#include <linux/kthread.h>
  52#include <linux/kernel.h>
  53#include <linux/syscalls.h>
  54
  55#include <linux/audit.h>
  56
  57#include <net/sock.h>
  58#include <net/netlink.h>
  59#include <linux/skbuff.h>
  60#ifdef CONFIG_SECURITY
  61#include <linux/security.h>
  62#endif
  63#include <net/netlink.h>
  64#include <linux/freezer.h>
  65#include <linux/tty.h>
  66#include <linux/pid_namespace.h>
  67
  68#include "audit.h"
  69
  70/* No auditing will take place until audit_initialized == AUDIT_INITIALIZED.
  71 * (Initialization happens after skb_init is called.) */
  72#define AUDIT_DISABLED          -1
  73#define AUDIT_UNINITIALIZED     0
  74#define AUDIT_INITIALIZED       1
  75static int      audit_initialized;
  76
  77#define AUDIT_OFF       0
  78#define AUDIT_ON        1
  79#define AUDIT_LOCKED    2
  80int             audit_enabled;
  81int             audit_ever_enabled;
  82
  83EXPORT_SYMBOL_GPL(audit_enabled);
  84
  85/* Default state when kernel boots without any parameters. */
  86static int      audit_default;
  87
  88/* If auditing cannot proceed, audit_failure selects what happens. */
  89static int      audit_failure = AUDIT_FAIL_PRINTK;
  90
  91/*
  92 * If audit records are to be written to the netlink socket, audit_pid
  93 * contains the pid of the auditd process and audit_nlk_portid contains
  94 * the portid to use to send netlink messages to that process.
  95 */
  96int             audit_pid;
  97static int      audit_nlk_portid;
  98
  99/* If audit_rate_limit is non-zero, limit the rate of sending audit records
 100 * to that number per second.  This prevents DoS attacks, but results in
 101 * audit records being dropped. */
 102static int      audit_rate_limit;
 103
 104/* Number of outstanding audit_buffers allowed. */
 105static int      audit_backlog_limit = 64;
 106static int      audit_backlog_wait_time = 60 * HZ;
 107static int      audit_backlog_wait_overflow = 0;
 108
 109/* The identity of the user shutting down the audit system. */
 110kuid_t          audit_sig_uid = INVALID_UID;
 111pid_t           audit_sig_pid = -1;
 112u32             audit_sig_sid = 0;
 113
 114/* Records can be lost in several ways:
 115   0) [suppressed in audit_alloc]
 116   1) out of memory in audit_log_start [kmalloc of struct audit_buffer]
 117   2) out of memory in audit_log_move [alloc_skb]
 118   3) suppressed due to audit_rate_limit
 119   4) suppressed due to audit_backlog_limit
 120*/
 121static atomic_t    audit_lost = ATOMIC_INIT(0);
 122
 123/* The netlink socket. */
 124static struct sock *audit_sock;
 125
 126/* Hash for inode-based rules */
 127struct list_head audit_inode_hash[AUDIT_INODE_BUCKETS];
 128
 129/* The audit_freelist is a list of pre-allocated audit buffers (if more
 130 * than AUDIT_MAXFREE are in use, the audit buffer is freed instead of
 131 * being placed on the freelist). */
 132static DEFINE_SPINLOCK(audit_freelist_lock);
 133static int         audit_freelist_count;
 134static LIST_HEAD(audit_freelist);
 135
 136static struct sk_buff_head audit_skb_queue;
 137/* queue of skbs to send to auditd when/if it comes back */
 138static struct sk_buff_head audit_skb_hold_queue;
 139static struct task_struct *kauditd_task;
 140static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait);
 141static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait);
 142
 143/* Serialize requests from userspace. */
 144DEFINE_MUTEX(audit_cmd_mutex);
 145
 146/* AUDIT_BUFSIZ is the size of the temporary buffer used for formatting
 147 * audit records.  Since printk uses a 1024 byte buffer, this buffer
 148 * should be at least that large. */
 149#define AUDIT_BUFSIZ 1024
 150
 151/* AUDIT_MAXFREE is the number of empty audit_buffers we keep on the
 152 * audit_freelist.  Doing so eliminates many kmalloc/kfree calls. */
 153#define AUDIT_MAXFREE  (2*NR_CPUS)
 154
 155/* The audit_buffer is used when formatting an audit record.  The caller
 156 * locks briefly to get the record off the freelist or to allocate the
 157 * buffer, and locks briefly to send the buffer to the netlink layer or
 158 * to place it on a transmit queue.  Multiple audit_buffers can be in
 159 * use simultaneously. */
 160struct audit_buffer {
 161        struct list_head     list;
 162        struct sk_buff       *skb;      /* formatted skb ready to send */
 163        struct audit_context *ctx;      /* NULL or associated context */
 164        gfp_t                gfp_mask;
 165};
 166
 167struct audit_reply {
 168        int pid;
 169        struct sk_buff *skb;
 170};
 171
 172static void audit_set_pid(struct audit_buffer *ab, pid_t pid)
 173{
 174        if (ab) {
 175                struct nlmsghdr *nlh = nlmsg_hdr(ab->skb);
 176                nlh->nlmsg_pid = pid;
 177        }
 178}
 179
 180void audit_panic(const char *message)
 181{
 182        switch (audit_failure)
 183        {
 184        case AUDIT_FAIL_SILENT:
 185                break;
 186        case AUDIT_FAIL_PRINTK:
 187                if (printk_ratelimit())
 188                        printk(KERN_ERR "audit: %s\n", message);
 189                break;
 190        case AUDIT_FAIL_PANIC:
 191                /* test audit_pid since printk is always losey, why bother? */
 192                if (audit_pid)
 193                        panic("audit: %s\n", message);
 194                break;
 195        }
 196}
 197
 198static inline int audit_rate_check(void)
 199{
 200        static unsigned long    last_check = 0;
 201        static int              messages   = 0;
 202        static DEFINE_SPINLOCK(lock);
 203        unsigned long           flags;
 204        unsigned long           now;
 205        unsigned long           elapsed;
 206        int                     retval     = 0;
 207
 208        if (!audit_rate_limit) return 1;
 209
 210        spin_lock_irqsave(&lock, flags);
 211        if (++messages < audit_rate_limit) {
 212                retval = 1;
 213        } else {
 214                now     = jiffies;
 215                elapsed = now - last_check;
 216                if (elapsed > HZ) {
 217                        last_check = now;
 218                        messages   = 0;
 219                        retval     = 1;
 220                }
 221        }
 222        spin_unlock_irqrestore(&lock, flags);
 223
 224        return retval;
 225}
 226
 227/**
 228 * audit_log_lost - conditionally log lost audit message event
 229 * @message: the message stating reason for lost audit message
 230 *
 231 * Emit at least 1 message per second, even if audit_rate_check is
 232 * throttling.
 233 * Always increment the lost messages counter.
 234*/
 235void audit_log_lost(const char *message)
 236{
 237        static unsigned long    last_msg = 0;
 238        static DEFINE_SPINLOCK(lock);
 239        unsigned long           flags;
 240        unsigned long           now;
 241        int                     print;
 242
 243        atomic_inc(&audit_lost);
 244
 245        print = (audit_failure == AUDIT_FAIL_PANIC || !audit_rate_limit);
 246
 247        if (!print) {
 248                spin_lock_irqsave(&lock, flags);
 249                now = jiffies;
 250                if (now - last_msg > HZ) {
 251                        print = 1;
 252                        last_msg = now;
 253                }
 254                spin_unlock_irqrestore(&lock, flags);
 255        }
 256
 257        if (print) {
 258                if (printk_ratelimit())
 259                        printk(KERN_WARNING
 260                                "audit: audit_lost=%d audit_rate_limit=%d "
 261                                "audit_backlog_limit=%d\n",
 262                                atomic_read(&audit_lost),
 263                                audit_rate_limit,
 264                                audit_backlog_limit);
 265                audit_panic(message);
 266        }
 267}
 268
 269static int audit_log_config_change(char *function_name, int new, int old,
 270                                   int allow_changes)
 271{
 272        struct audit_buffer *ab;
 273        int rc = 0;
 274
 275        ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
 276        if (unlikely(!ab))
 277                return rc;
 278        audit_log_format(ab, "%s=%d old=%d", function_name, new, old);
 279        audit_log_session_info(ab);
 280        rc = audit_log_task_context(ab);
 281        if (rc)
 282                allow_changes = 0; /* Something weird, deny request */
 283        audit_log_format(ab, " res=%d", allow_changes);
 284        audit_log_end(ab);
 285        return rc;
 286}
 287
 288static int audit_do_config_change(char *function_name, int *to_change, int new)
 289{
 290        int allow_changes, rc = 0, old = *to_change;
 291
 292        /* check if we are locked */
 293        if (audit_enabled == AUDIT_LOCKED)
 294                allow_changes = 0;
 295        else
 296                allow_changes = 1;
 297
 298        if (audit_enabled != AUDIT_OFF) {
 299                rc = audit_log_config_change(function_name, new, old, allow_changes);
 300                if (rc)
 301                        allow_changes = 0;
 302        }
 303
 304        /* If we are allowed, make the change */
 305        if (allow_changes == 1)
 306                *to_change = new;
 307        /* Not allowed, update reason */
 308        else if (rc == 0)
 309                rc = -EPERM;
 310        return rc;
 311}
 312
 313static int audit_set_rate_limit(int limit)
 314{
 315        return audit_do_config_change("audit_rate_limit", &audit_rate_limit, limit);
 316}
 317
 318static int audit_set_backlog_limit(int limit)
 319{
 320        return audit_do_config_change("audit_backlog_limit", &audit_backlog_limit, limit);
 321}
 322
 323static int audit_set_enabled(int state)
 324{
 325        int rc;
 326        if (state < AUDIT_OFF || state > AUDIT_LOCKED)
 327                return -EINVAL;
 328
 329        rc =  audit_do_config_change("audit_enabled", &audit_enabled, state);
 330        if (!rc)
 331                audit_ever_enabled |= !!state;
 332
 333        return rc;
 334}
 335
 336static int audit_set_failure(int state)
 337{
 338        if (state != AUDIT_FAIL_SILENT
 339            && state != AUDIT_FAIL_PRINTK
 340            && state != AUDIT_FAIL_PANIC)
 341                return -EINVAL;
 342
 343        return audit_do_config_change("audit_failure", &audit_failure, state);
 344}
 345
 346/*
 347 * Queue skbs to be sent to auditd when/if it comes back.  These skbs should
 348 * already have been sent via prink/syslog and so if these messages are dropped
 349 * it is not a huge concern since we already passed the audit_log_lost()
 350 * notification and stuff.  This is just nice to get audit messages during
 351 * boot before auditd is running or messages generated while auditd is stopped.
 352 * This only holds messages is audit_default is set, aka booting with audit=1
 353 * or building your kernel that way.
 354 */
 355static void audit_hold_skb(struct sk_buff *skb)
 356{
 357        if (audit_default &&
 358            skb_queue_len(&audit_skb_hold_queue) < audit_backlog_limit)
 359                skb_queue_tail(&audit_skb_hold_queue, skb);
 360        else
 361                kfree_skb(skb);
 362}
 363
 364/*
 365 * For one reason or another this nlh isn't getting delivered to the userspace
 366 * audit daemon, just send it to printk.
 367 */
 368static void audit_printk_skb(struct sk_buff *skb)
 369{
 370        struct nlmsghdr *nlh = nlmsg_hdr(skb);
 371        char *data = nlmsg_data(nlh);
 372
 373        if (nlh->nlmsg_type != AUDIT_EOE) {
 374                if (printk_ratelimit())
 375                        printk(KERN_NOTICE "type=%d %s\n", nlh->nlmsg_type, data);
 376                else
 377                        audit_log_lost("printk limit exceeded\n");
 378        }
 379
 380        audit_hold_skb(skb);
 381}
 382
 383static void kauditd_send_skb(struct sk_buff *skb)
 384{
 385        int err;
 386        /* take a reference in case we can't send it and we want to hold it */
 387        skb_get(skb);
 388        err = netlink_unicast(audit_sock, skb, audit_nlk_portid, 0);
 389        if (err < 0) {
 390                BUG_ON(err != -ECONNREFUSED); /* Shouldn't happen */
 391                printk(KERN_ERR "audit: *NO* daemon at audit_pid=%d\n", audit_pid);
 392                audit_log_lost("auditd disappeared\n");
 393                audit_pid = 0;
 394                /* we might get lucky and get this in the next auditd */
 395                audit_hold_skb(skb);
 396        } else
 397                /* drop the extra reference if sent ok */
 398                consume_skb(skb);
 399}
 400
 401/*
 402 * flush_hold_queue - empty the hold queue if auditd appears
 403 *
 404 * If auditd just started, drain the queue of messages already
 405 * sent to syslog/printk.  Remember loss here is ok.  We already
 406 * called audit_log_lost() if it didn't go out normally.  so the
 407 * race between the skb_dequeue and the next check for audit_pid
 408 * doesn't matter.
 409 *
 410 * If you ever find kauditd to be too slow we can get a perf win
 411 * by doing our own locking and keeping better track if there
 412 * are messages in this queue.  I don't see the need now, but
 413 * in 5 years when I want to play with this again I'll see this
 414 * note and still have no friggin idea what i'm thinking today.
 415 */
 416static void flush_hold_queue(void)
 417{
 418        struct sk_buff *skb;
 419
 420        if (!audit_default || !audit_pid)
 421                return;
 422
 423        skb = skb_dequeue(&audit_skb_hold_queue);
 424        if (likely(!skb))
 425                return;
 426
 427        while (skb && audit_pid) {
 428                kauditd_send_skb(skb);
 429                skb = skb_dequeue(&audit_skb_hold_queue);
 430        }
 431
 432        /*
 433         * if auditd just disappeared but we
 434         * dequeued an skb we need to drop ref
 435         */
 436        if (skb)
 437                consume_skb(skb);
 438}
 439
 440static int kauditd_thread(void *dummy)
 441{
 442        set_freezable();
 443        while (!kthread_should_stop()) {
 444                struct sk_buff *skb;
 445                DECLARE_WAITQUEUE(wait, current);
 446
 447                flush_hold_queue();
 448
 449                skb = skb_dequeue(&audit_skb_queue);
 450                wake_up(&audit_backlog_wait);
 451                if (skb) {
 452                        if (audit_pid)
 453                                kauditd_send_skb(skb);
 454                        else
 455                                audit_printk_skb(skb);
 456                        continue;
 457                }
 458                set_current_state(TASK_INTERRUPTIBLE);
 459                add_wait_queue(&kauditd_wait, &wait);
 460
 461                if (!skb_queue_len(&audit_skb_queue)) {
 462                        try_to_freeze();
 463                        schedule();
 464                }
 465
 466                __set_current_state(TASK_RUNNING);
 467                remove_wait_queue(&kauditd_wait, &wait);
 468        }
 469        return 0;
 470}
 471
 472int audit_send_list(void *_dest)
 473{
 474        struct audit_netlink_list *dest = _dest;
 475        int pid = dest->pid;
 476        struct sk_buff *skb;
 477
 478        /* wait for parent to finish and send an ACK */
 479        mutex_lock(&audit_cmd_mutex);
 480        mutex_unlock(&audit_cmd_mutex);
 481
 482        while ((skb = __skb_dequeue(&dest->q)) != NULL)
 483                netlink_unicast(audit_sock, skb, pid, 0);
 484
 485        kfree(dest);
 486
 487        return 0;
 488}
 489
 490struct sk_buff *audit_make_reply(int pid, int seq, int type, int done,
 491                                 int multi, const void *payload, int size)
 492{
 493        struct sk_buff  *skb;
 494        struct nlmsghdr *nlh;
 495        void            *data;
 496        int             flags = multi ? NLM_F_MULTI : 0;
 497        int             t     = done  ? NLMSG_DONE  : type;
 498
 499        skb = nlmsg_new(size, GFP_KERNEL);
 500        if (!skb)
 501                return NULL;
 502
 503        nlh     = nlmsg_put(skb, pid, seq, t, size, flags);
 504        if (!nlh)
 505                goto out_kfree_skb;
 506        data = nlmsg_data(nlh);
 507        memcpy(data, payload, size);
 508        return skb;
 509
 510out_kfree_skb:
 511        kfree_skb(skb);
 512        return NULL;
 513}
 514
 515static int audit_send_reply_thread(void *arg)
 516{
 517        struct audit_reply *reply = (struct audit_reply *)arg;
 518
 519        mutex_lock(&audit_cmd_mutex);
 520        mutex_unlock(&audit_cmd_mutex);
 521
 522        /* Ignore failure. It'll only happen if the sender goes away,
 523           because our timeout is set to infinite. */
 524        netlink_unicast(audit_sock, reply->skb, reply->pid, 0);
 525        kfree(reply);
 526        return 0;
 527}
 528/**
 529 * audit_send_reply - send an audit reply message via netlink
 530 * @pid: process id to send reply to
 531 * @seq: sequence number
 532 * @type: audit message type
 533 * @done: done (last) flag
 534 * @multi: multi-part message flag
 535 * @payload: payload data
 536 * @size: payload size
 537 *
 538 * Allocates an skb, builds the netlink message, and sends it to the pid.
 539 * No failure notifications.
 540 */
 541static void audit_send_reply(int pid, int seq, int type, int done, int multi,
 542                             const void *payload, int size)
 543{
 544        struct sk_buff *skb;
 545        struct task_struct *tsk;
 546        struct audit_reply *reply = kmalloc(sizeof(struct audit_reply),
 547                                            GFP_KERNEL);
 548
 549        if (!reply)
 550                return;
 551
 552        skb = audit_make_reply(pid, seq, type, done, multi, payload, size);
 553        if (!skb)
 554                goto out;
 555
 556        reply->pid = pid;
 557        reply->skb = skb;
 558
 559        tsk = kthread_run(audit_send_reply_thread, reply, "audit_send_reply");
 560        if (!IS_ERR(tsk))
 561                return;
 562        kfree_skb(skb);
 563out:
 564        kfree(reply);
 565}
 566
 567/*
 568 * Check for appropriate CAP_AUDIT_ capabilities on incoming audit
 569 * control messages.
 570 */
 571static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type)
 572{
 573        int err = 0;
 574
 575        /* Only support the initial namespaces for now. */
 576        if ((current_user_ns() != &init_user_ns) ||
 577            (task_active_pid_ns(current) != &init_pid_ns))
 578                return -EPERM;
 579
 580        switch (msg_type) {
 581        case AUDIT_LIST:
 582        case AUDIT_ADD:
 583        case AUDIT_DEL:
 584                return -EOPNOTSUPP;
 585        case AUDIT_GET:
 586        case AUDIT_SET:
 587        case AUDIT_LIST_RULES:
 588        case AUDIT_ADD_RULE:
 589        case AUDIT_DEL_RULE:
 590        case AUDIT_SIGNAL_INFO:
 591        case AUDIT_TTY_GET:
 592        case AUDIT_TTY_SET:
 593        case AUDIT_TRIM:
 594        case AUDIT_MAKE_EQUIV:
 595                if (!capable(CAP_AUDIT_CONTROL))
 596                        err = -EPERM;
 597                break;
 598        case AUDIT_USER:
 599        case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
 600        case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
 601                if (!capable(CAP_AUDIT_WRITE))
 602                        err = -EPERM;
 603                break;
 604        default:  /* bad msg */
 605                err = -EINVAL;
 606        }
 607
 608        return err;
 609}
 610
 611static int audit_log_common_recv_msg(struct audit_buffer **ab, u16 msg_type)
 612{
 613        int rc = 0;
 614        uid_t uid = from_kuid(&init_user_ns, current_uid());
 615
 616        if (!audit_enabled) {
 617                *ab = NULL;
 618                return rc;
 619        }
 620
 621        *ab = audit_log_start(NULL, GFP_KERNEL, msg_type);
 622        if (unlikely(!*ab))
 623                return rc;
 624        audit_log_format(*ab, "pid=%d uid=%u", task_tgid_vnr(current), uid);
 625        audit_log_session_info(*ab);
 626        audit_log_task_context(*ab);
 627
 628        return rc;
 629}
 630
 631static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 632{
 633        u32                     seq;
 634        void                    *data;
 635        struct audit_status     *status_get, status_set;
 636        int                     err;
 637        struct audit_buffer     *ab;
 638        u16                     msg_type = nlh->nlmsg_type;
 639        struct audit_sig_info   *sig_data;
 640        char                    *ctx = NULL;
 641        u32                     len;
 642
 643        err = audit_netlink_ok(skb, msg_type);
 644        if (err)
 645                return err;
 646
 647        /* As soon as there's any sign of userspace auditd,
 648         * start kauditd to talk to it */
 649        if (!kauditd_task) {
 650                kauditd_task = kthread_run(kauditd_thread, NULL, "kauditd");
 651                if (IS_ERR(kauditd_task)) {
 652                        err = PTR_ERR(kauditd_task);
 653                        kauditd_task = NULL;
 654                        return err;
 655                }
 656        }
 657        seq  = nlh->nlmsg_seq;
 658        data = nlmsg_data(nlh);
 659
 660        switch (msg_type) {
 661        case AUDIT_GET:
 662                status_set.enabled       = audit_enabled;
 663                status_set.failure       = audit_failure;
 664                status_set.pid           = audit_pid;
 665                status_set.rate_limit    = audit_rate_limit;
 666                status_set.backlog_limit = audit_backlog_limit;
 667                status_set.lost          = atomic_read(&audit_lost);
 668                status_set.backlog       = skb_queue_len(&audit_skb_queue);
 669                audit_send_reply(NETLINK_CB(skb).portid, seq, AUDIT_GET, 0, 0,
 670                                 &status_set, sizeof(status_set));
 671                break;
 672        case AUDIT_SET:
 673                if (nlh->nlmsg_len < sizeof(struct audit_status))
 674                        return -EINVAL;
 675                status_get   = (struct audit_status *)data;
 676                if (status_get->mask & AUDIT_STATUS_ENABLED) {
 677                        err = audit_set_enabled(status_get->enabled);
 678                        if (err < 0)
 679                                return err;
 680                }
 681                if (status_get->mask & AUDIT_STATUS_FAILURE) {
 682                        err = audit_set_failure(status_get->failure);
 683                        if (err < 0)
 684                                return err;
 685                }
 686                if (status_get->mask & AUDIT_STATUS_PID) {
 687                        int new_pid = status_get->pid;
 688
 689                        if (audit_enabled != AUDIT_OFF)
 690                                audit_log_config_change("audit_pid", new_pid, audit_pid, 1);
 691                        audit_pid = new_pid;
 692                        audit_nlk_portid = NETLINK_CB(skb).portid;
 693                }
 694                if (status_get->mask & AUDIT_STATUS_RATE_LIMIT) {
 695                        err = audit_set_rate_limit(status_get->rate_limit);
 696                        if (err < 0)
 697                                return err;
 698                }
 699                if (status_get->mask & AUDIT_STATUS_BACKLOG_LIMIT)
 700                        err = audit_set_backlog_limit(status_get->backlog_limit);
 701                break;
 702        case AUDIT_USER:
 703        case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
 704        case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
 705                if (!audit_enabled && msg_type != AUDIT_USER_AVC)
 706                        return 0;
 707
 708                err = audit_filter_user(msg_type);
 709                if (err == 1) {
 710                        err = 0;
 711                        if (msg_type == AUDIT_USER_TTY) {
 712                                err = tty_audit_push_current();
 713                                if (err)
 714                                        break;
 715                        }
 716                        audit_log_common_recv_msg(&ab, msg_type);
 717                        if (msg_type != AUDIT_USER_TTY)
 718                                audit_log_format(ab, " msg='%.1024s'",
 719                                                 (char *)data);
 720                        else {
 721                                int size;
 722
 723                                audit_log_format(ab, " data=");
 724                                size = nlmsg_len(nlh);
 725                                if (size > 0 &&
 726                                    ((unsigned char *)data)[size - 1] == '\0')
 727                                        size--;
 728                                audit_log_n_untrustedstring(ab, data, size);
 729                        }
 730                        audit_set_pid(ab, NETLINK_CB(skb).portid);
 731                        audit_log_end(ab);
 732                }
 733                break;
 734        case AUDIT_ADD_RULE:
 735        case AUDIT_DEL_RULE:
 736                if (nlmsg_len(nlh) < sizeof(struct audit_rule_data))
 737                        return -EINVAL;
 738                if (audit_enabled == AUDIT_LOCKED) {
 739                        audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
 740                        audit_log_format(ab, " audit_enabled=%d res=0", audit_enabled);
 741                        audit_log_end(ab);
 742                        return -EPERM;
 743                }
 744                /* fallthrough */
 745        case AUDIT_LIST_RULES:
 746                err = audit_receive_filter(msg_type, NETLINK_CB(skb).portid,
 747                                           seq, data, nlmsg_len(nlh));
 748                break;
 749        case AUDIT_TRIM:
 750                audit_trim_trees();
 751                audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
 752                audit_log_format(ab, " op=trim res=1");
 753                audit_log_end(ab);
 754                break;
 755        case AUDIT_MAKE_EQUIV: {
 756                void *bufp = data;
 757                u32 sizes[2];
 758                size_t msglen = nlmsg_len(nlh);
 759                char *old, *new;
 760
 761                err = -EINVAL;
 762                if (msglen < 2 * sizeof(u32))
 763                        break;
 764                memcpy(sizes, bufp, 2 * sizeof(u32));
 765                bufp += 2 * sizeof(u32);
 766                msglen -= 2 * sizeof(u32);
 767                old = audit_unpack_string(&bufp, &msglen, sizes[0]);
 768                if (IS_ERR(old)) {
 769                        err = PTR_ERR(old);
 770                        break;
 771                }
 772                new = audit_unpack_string(&bufp, &msglen, sizes[1]);
 773                if (IS_ERR(new)) {
 774                        err = PTR_ERR(new);
 775                        kfree(old);
 776                        break;
 777                }
 778                /* OK, here comes... */
 779                err = audit_tag_tree(old, new);
 780
 781                audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
 782
 783                audit_log_format(ab, " op=make_equiv old=");
 784                audit_log_untrustedstring(ab, old);
 785                audit_log_format(ab, " new=");
 786                audit_log_untrustedstring(ab, new);
 787                audit_log_format(ab, " res=%d", !err);
 788                audit_log_end(ab);
 789                kfree(old);
 790                kfree(new);
 791                break;
 792        }
 793        case AUDIT_SIGNAL_INFO:
 794                len = 0;
 795                if (audit_sig_sid) {
 796                        err = security_secid_to_secctx(audit_sig_sid, &ctx, &len);
 797                        if (err)
 798                                return err;
 799                }
 800                sig_data = kmalloc(sizeof(*sig_data) + len, GFP_KERNEL);
 801                if (!sig_data) {
 802                        if (audit_sig_sid)
 803                                security_release_secctx(ctx, len);
 804                        return -ENOMEM;
 805                }
 806                sig_data->uid = from_kuid(&init_user_ns, audit_sig_uid);
 807                sig_data->pid = audit_sig_pid;
 808                if (audit_sig_sid) {
 809                        memcpy(sig_data->ctx, ctx, len);
 810                        security_release_secctx(ctx, len);
 811                }
 812                audit_send_reply(NETLINK_CB(skb).portid, seq, AUDIT_SIGNAL_INFO,
 813                                0, 0, sig_data, sizeof(*sig_data) + len);
 814                kfree(sig_data);
 815                break;
 816        case AUDIT_TTY_GET: {
 817                struct audit_tty_status s;
 818                struct task_struct *tsk = current;
 819
 820                spin_lock(&tsk->sighand->siglock);
 821                s.enabled = tsk->signal->audit_tty != 0;
 822                s.log_passwd = tsk->signal->audit_tty_log_passwd;
 823                spin_unlock(&tsk->sighand->siglock);
 824
 825                audit_send_reply(NETLINK_CB(skb).portid, seq,
 826                                 AUDIT_TTY_GET, 0, 0, &s, sizeof(s));
 827                break;
 828        }
 829        case AUDIT_TTY_SET: {
 830                struct audit_tty_status s;
 831                struct task_struct *tsk = current;
 832
 833                memset(&s, 0, sizeof(s));
 834                /* guard against past and future API changes */
 835                memcpy(&s, data, min(sizeof(s), (size_t)nlh->nlmsg_len));
 836                if ((s.enabled != 0 && s.enabled != 1) ||
 837                    (s.log_passwd != 0 && s.log_passwd != 1))
 838                        return -EINVAL;
 839
 840                spin_lock(&tsk->sighand->siglock);
 841                tsk->signal->audit_tty = s.enabled;
 842                tsk->signal->audit_tty_log_passwd = s.log_passwd;
 843                spin_unlock(&tsk->sighand->siglock);
 844                break;
 845        }
 846        default:
 847                err = -EINVAL;
 848                break;
 849        }
 850
 851        return err < 0 ? err : 0;
 852}
 853
 854/*
 855 * Get message from skb.  Each message is processed by audit_receive_msg.
 856 * Malformed skbs with wrong length are discarded silently.
 857 */
 858static void audit_receive_skb(struct sk_buff *skb)
 859{
 860        struct nlmsghdr *nlh;
 861        /*
 862         * len MUST be signed for nlmsg_next to be able to dec it below 0
 863         * if the nlmsg_len was not aligned
 864         */
 865        int len;
 866        int err;
 867
 868        nlh = nlmsg_hdr(skb);
 869        len = skb->len;
 870
 871        while (nlmsg_ok(nlh, len)) {
 872                err = audit_receive_msg(skb, nlh);
 873                /* if err or if this message says it wants a response */
 874                if (err || (nlh->nlmsg_flags & NLM_F_ACK))
 875                        netlink_ack(skb, nlh, err);
 876
 877                nlh = nlmsg_next(nlh, &len);
 878        }
 879}
 880
 881/* Receive messages from netlink socket. */
 882static void audit_receive(struct sk_buff  *skb)
 883{
 884        mutex_lock(&audit_cmd_mutex);
 885        audit_receive_skb(skb);
 886        mutex_unlock(&audit_cmd_mutex);
 887}
 888
 889/* Initialize audit support at boot time. */
 890static int __init audit_init(void)
 891{
 892        int i;
 893        struct netlink_kernel_cfg cfg = {
 894                .input  = audit_receive,
 895        };
 896
 897        if (audit_initialized == AUDIT_DISABLED)
 898                return 0;
 899
 900        printk(KERN_INFO "audit: initializing netlink socket (%s)\n",
 901               audit_default ? "enabled" : "disabled");
 902        audit_sock = netlink_kernel_create(&init_net, NETLINK_AUDIT, &cfg);
 903        if (!audit_sock)
 904                audit_panic("cannot initialize netlink socket");
 905        else
 906                audit_sock->sk_sndtimeo = MAX_SCHEDULE_TIMEOUT;
 907
 908        skb_queue_head_init(&audit_skb_queue);
 909        skb_queue_head_init(&audit_skb_hold_queue);
 910        audit_initialized = AUDIT_INITIALIZED;
 911        audit_enabled = audit_default;
 912        audit_ever_enabled |= !!audit_default;
 913
 914        audit_log(NULL, GFP_KERNEL, AUDIT_KERNEL, "initialized");
 915
 916        for (i = 0; i < AUDIT_INODE_BUCKETS; i++)
 917                INIT_LIST_HEAD(&audit_inode_hash[i]);
 918
 919        return 0;
 920}
 921__initcall(audit_init);
 922
 923/* Process kernel command-line parameter at boot time.  audit=0 or audit=1. */
 924static int __init audit_enable(char *str)
 925{
 926        audit_default = !!simple_strtol(str, NULL, 0);
 927        if (!audit_default)
 928                audit_initialized = AUDIT_DISABLED;
 929
 930        printk(KERN_INFO "audit: %s", audit_default ? "enabled" : "disabled");
 931
 932        if (audit_initialized == AUDIT_INITIALIZED) {
 933                audit_enabled = audit_default;
 934                audit_ever_enabled |= !!audit_default;
 935        } else if (audit_initialized == AUDIT_UNINITIALIZED) {
 936                printk(" (after initialization)");
 937        } else {
 938                printk(" (until reboot)");
 939        }
 940        printk("\n");
 941
 942        return 1;
 943}
 944
 945__setup("audit=", audit_enable);
 946
 947static void audit_buffer_free(struct audit_buffer *ab)
 948{
 949        unsigned long flags;
 950
 951        if (!ab)
 952                return;
 953
 954        if (ab->skb)
 955                kfree_skb(ab->skb);
 956
 957        spin_lock_irqsave(&audit_freelist_lock, flags);
 958        if (audit_freelist_count > AUDIT_MAXFREE)
 959                kfree(ab);
 960        else {
 961                audit_freelist_count++;
 962                list_add(&ab->list, &audit_freelist);
 963        }
 964        spin_unlock_irqrestore(&audit_freelist_lock, flags);
 965}
 966
 967static struct audit_buffer * audit_buffer_alloc(struct audit_context *ctx,
 968                                                gfp_t gfp_mask, int type)
 969{
 970        unsigned long flags;
 971        struct audit_buffer *ab = NULL;
 972        struct nlmsghdr *nlh;
 973
 974        spin_lock_irqsave(&audit_freelist_lock, flags);
 975        if (!list_empty(&audit_freelist)) {
 976                ab = list_entry(audit_freelist.next,
 977                                struct audit_buffer, list);
 978                list_del(&ab->list);
 979                --audit_freelist_count;
 980        }
 981        spin_unlock_irqrestore(&audit_freelist_lock, flags);
 982
 983        if (!ab) {
 984                ab = kmalloc(sizeof(*ab), gfp_mask);
 985                if (!ab)
 986                        goto err;
 987        }
 988
 989        ab->ctx = ctx;
 990        ab->gfp_mask = gfp_mask;
 991
 992        ab->skb = nlmsg_new(AUDIT_BUFSIZ, gfp_mask);
 993        if (!ab->skb)
 994                goto err;
 995
 996        nlh = nlmsg_put(ab->skb, 0, 0, type, 0, 0);
 997        if (!nlh)
 998                goto out_kfree_skb;
 999
1000        return ab;
1001
1002out_kfree_skb:
1003        kfree_skb(ab->skb);
1004        ab->skb = NULL;
1005err:
1006        audit_buffer_free(ab);
1007        return NULL;
1008}
1009
1010/**
1011 * audit_serial - compute a serial number for the audit record
1012 *
1013 * Compute a serial number for the audit record.  Audit records are
1014 * written to user-space as soon as they are generated, so a complete
1015 * audit record may be written in several pieces.  The timestamp of the
1016 * record and this serial number are used by the user-space tools to
1017 * determine which pieces belong to the same audit record.  The
1018 * (timestamp,serial) tuple is unique for each syscall and is live from
1019 * syscall entry to syscall exit.
1020 *
1021 * NOTE: Another possibility is to store the formatted records off the
1022 * audit context (for those records that have a context), and emit them
1023 * all at syscall exit.  However, this could delay the reporting of
1024 * significant errors until syscall exit (or never, if the system
1025 * halts).
1026 */
1027unsigned int audit_serial(void)
1028{
1029        static DEFINE_SPINLOCK(serial_lock);
1030        static unsigned int serial = 0;
1031
1032        unsigned long flags;
1033        unsigned int ret;
1034
1035        spin_lock_irqsave(&serial_lock, flags);
1036        do {
1037                ret = ++serial;
1038        } while (unlikely(!ret));
1039        spin_unlock_irqrestore(&serial_lock, flags);
1040
1041        return ret;
1042}
1043
1044static inline void audit_get_stamp(struct audit_context *ctx,
1045                                   struct timespec *t, unsigned int *serial)
1046{
1047        if (!ctx || !auditsc_get_stamp(ctx, t, serial)) {
1048                *t = CURRENT_TIME;
1049                *serial = audit_serial();
1050        }
1051}
1052
1053/*
1054 * Wait for auditd to drain the queue a little
1055 */
1056static void wait_for_auditd(unsigned long sleep_time)
1057{
1058        DECLARE_WAITQUEUE(wait, current);
1059        set_current_state(TASK_UNINTERRUPTIBLE);
1060        add_wait_queue(&audit_backlog_wait, &wait);
1061
1062        if (audit_backlog_limit &&
1063            skb_queue_len(&audit_skb_queue) > audit_backlog_limit)
1064                schedule_timeout(sleep_time);
1065
1066        __set_current_state(TASK_RUNNING);
1067        remove_wait_queue(&audit_backlog_wait, &wait);
1068}
1069
1070/* Obtain an audit buffer.  This routine does locking to obtain the
1071 * audit buffer, but then no locking is required for calls to
1072 * audit_log_*format.  If the tsk is a task that is currently in a
1073 * syscall, then the syscall is marked as auditable and an audit record
1074 * will be written at syscall exit.  If there is no associated task, tsk
1075 * should be NULL. */
1076
1077/**
1078 * audit_log_start - obtain an audit buffer
1079 * @ctx: audit_context (may be NULL)
1080 * @gfp_mask: type of allocation
1081 * @type: audit message type
1082 *
1083 * Returns audit_buffer pointer on success or NULL on error.
1084 *
1085 * Obtain an audit buffer.  This routine does locking to obtain the
1086 * audit buffer, but then no locking is required for calls to
1087 * audit_log_*format.  If the task (ctx) is a task that is currently in a
1088 * syscall, then the syscall is marked as auditable and an audit record
1089 * will be written at syscall exit.  If there is no associated task, then
1090 * task context (ctx) should be NULL.
1091 */
1092struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
1093                                     int type)
1094{
1095        struct audit_buffer     *ab     = NULL;
1096        struct timespec         t;
1097        unsigned int            uninitialized_var(serial);
1098        int reserve;
1099        unsigned long timeout_start = jiffies;
1100
1101        if (audit_initialized != AUDIT_INITIALIZED)
1102                return NULL;
1103
1104        if (unlikely(audit_filter_type(type)))
1105                return NULL;
1106
1107        if (gfp_mask & __GFP_WAIT)
1108                reserve = 0;
1109        else
1110                reserve = 5; /* Allow atomic callers to go up to five
1111                                entries over the normal backlog limit */
1112
1113        while (audit_backlog_limit
1114               && skb_queue_len(&audit_skb_queue) > audit_backlog_limit + reserve) {
1115                if (gfp_mask & __GFP_WAIT && audit_backlog_wait_time) {
1116                        unsigned long sleep_time;
1117
1118                        sleep_time = timeout_start + audit_backlog_wait_time -
1119                                        jiffies;
1120                        if ((long)sleep_time > 0)
1121                                wait_for_auditd(sleep_time);
1122                        continue;
1123                }
1124                if (audit_rate_check() && printk_ratelimit())
1125                        printk(KERN_WARNING
1126                               "audit: audit_backlog=%d > "
1127                               "audit_backlog_limit=%d\n",
1128                               skb_queue_len(&audit_skb_queue),
1129                               audit_backlog_limit);
1130                audit_log_lost("backlog limit exceeded");
1131                audit_backlog_wait_time = audit_backlog_wait_overflow;
1132                wake_up(&audit_backlog_wait);
1133                return NULL;
1134        }
1135
1136        ab = audit_buffer_alloc(ctx, gfp_mask, type);
1137        if (!ab) {
1138                audit_log_lost("out of memory in audit_log_start");
1139                return NULL;
1140        }
1141
1142        audit_get_stamp(ab->ctx, &t, &serial);
1143
1144        audit_log_format(ab, "audit(%lu.%03lu:%u): ",
1145                         t.tv_sec, t.tv_nsec/1000000, serial);
1146        return ab;
1147}
1148
1149/**
1150 * audit_expand - expand skb in the audit buffer
1151 * @ab: audit_buffer
1152 * @extra: space to add at tail of the skb
1153 *
1154 * Returns 0 (no space) on failed expansion, or available space if
1155 * successful.
1156 */
1157static inline int audit_expand(struct audit_buffer *ab, int extra)
1158{
1159        struct sk_buff *skb = ab->skb;
1160        int oldtail = skb_tailroom(skb);
1161        int ret = pskb_expand_head(skb, 0, extra, ab->gfp_mask);
1162        int newtail = skb_tailroom(skb);
1163
1164        if (ret < 0) {
1165                audit_log_lost("out of memory in audit_expand");
1166                return 0;
1167        }
1168
1169        skb->truesize += newtail - oldtail;
1170        return newtail;
1171}
1172
1173/*
1174 * Format an audit message into the audit buffer.  If there isn't enough
1175 * room in the audit buffer, more room will be allocated and vsnprint
1176 * will be called a second time.  Currently, we assume that a printk
1177 * can't format message larger than 1024 bytes, so we don't either.
1178 */
1179static void audit_log_vformat(struct audit_buffer *ab, const char *fmt,
1180                              va_list args)
1181{
1182        int len, avail;
1183        struct sk_buff *skb;
1184        va_list args2;
1185
1186        if (!ab)
1187                return;
1188
1189        BUG_ON(!ab->skb);
1190        skb = ab->skb;
1191        avail = skb_tailroom(skb);
1192        if (avail == 0) {
1193                avail = audit_expand(ab, AUDIT_BUFSIZ);
1194                if (!avail)
1195                        goto out;
1196        }
1197        va_copy(args2, args);
1198        len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args);
1199        if (len >= avail) {
1200                /* The printk buffer is 1024 bytes long, so if we get
1201                 * here and AUDIT_BUFSIZ is at least 1024, then we can
1202                 * log everything that printk could have logged. */
1203                avail = audit_expand(ab,
1204                        max_t(unsigned, AUDIT_BUFSIZ, 1+len-avail));
1205                if (!avail)
1206                        goto out_va_end;
1207                len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args2);
1208        }
1209        if (len > 0)
1210                skb_put(skb, len);
1211out_va_end:
1212        va_end(args2);
1213out:
1214        return;
1215}
1216
1217/**
1218 * audit_log_format - format a message into the audit buffer.
1219 * @ab: audit_buffer
1220 * @fmt: format string
1221 * @...: optional parameters matching @fmt string
1222 *
1223 * All the work is done in audit_log_vformat.
1224 */
1225void audit_log_format(struct audit_buffer *ab, const char *fmt, ...)
1226{
1227        va_list args;
1228
1229        if (!ab)
1230                return;
1231        va_start(args, fmt);
1232        audit_log_vformat(ab, fmt, args);
1233        va_end(args);
1234}
1235
1236/**
1237 * audit_log_hex - convert a buffer to hex and append it to the audit skb
1238 * @ab: the audit_buffer
1239 * @buf: buffer to convert to hex
1240 * @len: length of @buf to be converted
1241 *
1242 * No return value; failure to expand is silently ignored.
1243 *
1244 * This function will take the passed buf and convert it into a string of
1245 * ascii hex digits. The new string is placed onto the skb.
1246 */
1247void audit_log_n_hex(struct audit_buffer *ab, const unsigned char *buf,
1248                size_t len)
1249{
1250        int i, avail, new_len;
1251        unsigned char *ptr;
1252        struct sk_buff *skb;
1253        static const unsigned char *hex = "0123456789ABCDEF";
1254
1255        if (!ab)
1256                return;
1257
1258        BUG_ON(!ab->skb);
1259        skb = ab->skb;
1260        avail = skb_tailroom(skb);
1261        new_len = len<<1;
1262        if (new_len >= avail) {
1263                /* Round the buffer request up to the next multiple */
1264                new_len = AUDIT_BUFSIZ*(((new_len-avail)/AUDIT_BUFSIZ) + 1);
1265                avail = audit_expand(ab, new_len);
1266                if (!avail)
1267                        return;
1268        }
1269
1270        ptr = skb_tail_pointer(skb);
1271        for (i=0; i<len; i++) {
1272                *ptr++ = hex[(buf[i] & 0xF0)>>4]; /* Upper nibble */
1273                *ptr++ = hex[buf[i] & 0x0F];      /* Lower nibble */
1274        }
1275        *ptr = 0;
1276        skb_put(skb, len << 1); /* new string is twice the old string */
1277}
1278
1279/*
1280 * Format a string of no more than slen characters into the audit buffer,
1281 * enclosed in quote marks.
1282 */
1283void audit_log_n_string(struct audit_buffer *ab, const char *string,
1284                        size_t slen)
1285{
1286        int avail, new_len;
1287        unsigned char *ptr;
1288        struct sk_buff *skb;
1289
1290        if (!ab)
1291                return;
1292
1293        BUG_ON(!ab->skb);
1294        skb = ab->skb;
1295        avail = skb_tailroom(skb);
1296        new_len = slen + 3;     /* enclosing quotes + null terminator */
1297        if (new_len > avail) {
1298                avail = audit_expand(ab, new_len);
1299                if (!avail)
1300                        return;
1301        }
1302        ptr = skb_tail_pointer(skb);
1303        *ptr++ = '"';
1304        memcpy(ptr, string, slen);
1305        ptr += slen;
1306        *ptr++ = '"';
1307        *ptr = 0;
1308        skb_put(skb, slen + 2); /* don't include null terminator */
1309}
1310
1311/**
1312 * audit_string_contains_control - does a string need to be logged in hex
1313 * @string: string to be checked
1314 * @len: max length of the string to check
1315 */
1316int audit_string_contains_control(const char *string, size_t len)
1317{
1318        const unsigned char *p;
1319        for (p = string; p < (const unsigned char *)string + len; p++) {
1320                if (*p == '"' || *p < 0x21 || *p > 0x7e)
1321                        return 1;
1322        }
1323        return 0;
1324}
1325
1326/**
1327 * audit_log_n_untrustedstring - log a string that may contain random characters
1328 * @ab: audit_buffer
1329 * @len: length of string (not including trailing null)
1330 * @string: string to be logged
1331 *
1332 * This code will escape a string that is passed to it if the string
1333 * contains a control character, unprintable character, double quote mark,
1334 * or a space. Unescaped strings will start and end with a double quote mark.
1335 * Strings that are escaped are printed in hex (2 digits per char).
1336 *
1337 * The caller specifies the number of characters in the string to log, which may
1338 * or may not be the entire string.
1339 */
1340void audit_log_n_untrustedstring(struct audit_buffer *ab, const char *string,
1341                                 size_t len)
1342{
1343        if (audit_string_contains_control(string, len))
1344                audit_log_n_hex(ab, string, len);
1345        else
1346                audit_log_n_string(ab, string, len);
1347}
1348
1349/**
1350 * audit_log_untrustedstring - log a string that may contain random characters
1351 * @ab: audit_buffer
1352 * @string: string to be logged
1353 *
1354 * Same as audit_log_n_untrustedstring(), except that strlen is used to
1355 * determine string length.
1356 */
1357void audit_log_untrustedstring(struct audit_buffer *ab, const char *string)
1358{
1359        audit_log_n_untrustedstring(ab, string, strlen(string));
1360}
1361
1362/* This is a helper-function to print the escaped d_path */
1363void audit_log_d_path(struct audit_buffer *ab, const char *prefix,
1364                      const struct path *path)
1365{
1366        char *p, *pathname;
1367
1368        if (prefix)
1369                audit_log_format(ab, "%s", prefix);
1370
1371        /* We will allow 11 spaces for ' (deleted)' to be appended */
1372        pathname = kmalloc(PATH_MAX+11, ab->gfp_mask);
1373        if (!pathname) {
1374                audit_log_string(ab, "<no_memory>");
1375                return;
1376        }
1377        p = d_path(path, pathname, PATH_MAX+11);
1378        if (IS_ERR(p)) { /* Should never happen since we send PATH_MAX */
1379                /* FIXME: can we save some information here? */
1380                audit_log_string(ab, "<too_long>");
1381        } else
1382                audit_log_untrustedstring(ab, p);
1383        kfree(pathname);
1384}
1385
1386void audit_log_session_info(struct audit_buffer *ab)
1387{
1388        u32 sessionid = audit_get_sessionid(current);
1389        uid_t auid = from_kuid(&init_user_ns, audit_get_loginuid(current));
1390
1391        audit_log_format(ab, " auid=%u ses=%u\n", auid, sessionid);
1392}
1393
1394void audit_log_key(struct audit_buffer *ab, char *key)
1395{
1396        audit_log_format(ab, " key=");
1397        if (key)
1398                audit_log_untrustedstring(ab, key);
1399        else
1400                audit_log_format(ab, "(null)");
1401}
1402
1403void audit_log_cap(struct audit_buffer *ab, char *prefix, kernel_cap_t *cap)
1404{
1405        int i;
1406
1407        audit_log_format(ab, " %s=", prefix);
1408        CAP_FOR_EACH_U32(i) {
1409                audit_log_format(ab, "%08x",
1410                                 cap->cap[(_KERNEL_CAPABILITY_U32S-1) - i]);
1411        }
1412}
1413
1414void audit_log_fcaps(struct audit_buffer *ab, struct audit_names *name)
1415{
1416        kernel_cap_t *perm = &name->fcap.permitted;
1417        kernel_cap_t *inh = &name->fcap.inheritable;
1418        int log = 0;
1419
1420        if (!cap_isclear(*perm)) {
1421                audit_log_cap(ab, "cap_fp", perm);
1422                log = 1;
1423        }
1424        if (!cap_isclear(*inh)) {
1425                audit_log_cap(ab, "cap_fi", inh);
1426                log = 1;
1427        }
1428
1429        if (log)
1430                audit_log_format(ab, " cap_fe=%d cap_fver=%x",
1431                                 name->fcap.fE, name->fcap_ver);
1432}
1433
1434static inline int audit_copy_fcaps(struct audit_names *name,
1435                                   const struct dentry *dentry)
1436{
1437        struct cpu_vfs_cap_data caps;
1438        int rc;
1439
1440        if (!dentry)
1441                return 0;
1442
1443        rc = get_vfs_caps_from_disk(dentry, &caps);
1444        if (rc)
1445                return rc;
1446
1447        name->fcap.permitted = caps.permitted;
1448        name->fcap.inheritable = caps.inheritable;
1449        name->fcap.fE = !!(caps.magic_etc & VFS_CAP_FLAGS_EFFECTIVE);
1450        name->fcap_ver = (caps.magic_etc & VFS_CAP_REVISION_MASK) >>
1451                                VFS_CAP_REVISION_SHIFT;
1452
1453        return 0;
1454}
1455
1456/* Copy inode data into an audit_names. */
1457void audit_copy_inode(struct audit_names *name, const struct dentry *dentry,
1458                      const struct inode *inode)
1459{
1460        name->ino   = inode->i_ino;
1461        name->dev   = inode->i_sb->s_dev;
1462        name->mode  = inode->i_mode;
1463        name->uid   = inode->i_uid;
1464        name->gid   = inode->i_gid;
1465        name->rdev  = inode->i_rdev;
1466        security_inode_getsecid(inode, &name->osid);
1467        audit_copy_fcaps(name, dentry);
1468}
1469
1470/**
1471 * audit_log_name - produce AUDIT_PATH record from struct audit_names
1472 * @context: audit_context for the task
1473 * @n: audit_names structure with reportable details
1474 * @path: optional path to report instead of audit_names->name
1475 * @record_num: record number to report when handling a list of names
1476 * @call_panic: optional pointer to int that will be updated if secid fails
1477 */
1478void audit_log_name(struct audit_context *context, struct audit_names *n,
1479                    struct path *path, int record_num, int *call_panic)
1480{
1481        struct audit_buffer *ab;
1482        ab = audit_log_start(context, GFP_KERNEL, AUDIT_PATH);
1483        if (!ab)
1484                return;
1485
1486        audit_log_format(ab, "item=%d", record_num);
1487
1488        if (path)
1489                audit_log_d_path(ab, " name=", path);
1490        else if (n->name) {
1491                switch (n->name_len) {
1492                case AUDIT_NAME_FULL:
1493                        /* log the full path */
1494                        audit_log_format(ab, " name=");
1495                        audit_log_untrustedstring(ab, n->name->name);
1496                        break;
1497                case 0:
1498                        /* name was specified as a relative path and the
1499                         * directory component is the cwd */
1500                        audit_log_d_path(ab, " name=", &context->pwd);
1501                        break;
1502                default:
1503                        /* log the name's directory component */
1504                        audit_log_format(ab, " name=");
1505                        audit_log_n_untrustedstring(ab, n->name->name,
1506                                                    n->name_len);
1507                }
1508        } else
1509                audit_log_format(ab, " name=(null)");
1510
1511        if (n->ino != (unsigned long)-1) {
1512                audit_log_format(ab, " inode=%lu"
1513                                 " dev=%02x:%02x mode=%#ho"
1514                                 " ouid=%u ogid=%u rdev=%02x:%02x",
1515                                 n->ino,
1516                                 MAJOR(n->dev),
1517                                 MINOR(n->dev),
1518                                 n->mode,
1519                                 from_kuid(&init_user_ns, n->uid),
1520                                 from_kgid(&init_user_ns, n->gid),
1521                                 MAJOR(n->rdev),
1522                                 MINOR(n->rdev));
1523        }
1524        if (n->osid != 0) {
1525                char *ctx = NULL;
1526                u32 len;
1527                if (security_secid_to_secctx(
1528                        n->osid, &ctx, &len)) {
1529                        audit_log_format(ab, " osid=%u", n->osid);
1530                        if (call_panic)
1531                                *call_panic = 2;
1532                } else {
1533                        audit_log_format(ab, " obj=%s", ctx);
1534                        security_release_secctx(ctx, len);
1535                }
1536        }
1537
1538        audit_log_fcaps(ab, n);
1539        audit_log_end(ab);
1540}
1541
1542int audit_log_task_context(struct audit_buffer *ab)
1543{
1544        char *ctx = NULL;
1545        unsigned len;
1546        int error;
1547        u32 sid;
1548
1549        security_task_getsecid(current, &sid);
1550        if (!sid)
1551                return 0;
1552
1553        error = security_secid_to_secctx(sid, &ctx, &len);
1554        if (error) {
1555                if (error != -EINVAL)
1556                        goto error_path;
1557                return 0;
1558        }
1559
1560        audit_log_format(ab, " subj=%s", ctx);
1561        security_release_secctx(ctx, len);
1562        return 0;
1563
1564error_path:
1565        audit_panic("error in audit_log_task_context");
1566        return error;
1567}
1568EXPORT_SYMBOL(audit_log_task_context);
1569
1570void audit_log_task_info(struct audit_buffer *ab, struct task_struct *tsk)
1571{
1572        const struct cred *cred;
1573        char name[sizeof(tsk->comm)];
1574        struct mm_struct *mm = tsk->mm;
1575        char *tty;
1576
1577        if (!ab)
1578                return;
1579
1580        /* tsk == current */
1581        cred = current_cred();
1582
1583        spin_lock_irq(&tsk->sighand->siglock);
1584        if (tsk->signal && tsk->signal->tty && tsk->signal->tty->name)
1585                tty = tsk->signal->tty->name;
1586        else
1587                tty = "(none)";
1588        spin_unlock_irq(&tsk->sighand->siglock);
1589
1590        audit_log_format(ab,
1591                         " ppid=%ld pid=%d auid=%u uid=%u gid=%u"
1592                         " euid=%u suid=%u fsuid=%u"
1593                         " egid=%u sgid=%u fsgid=%u ses=%u tty=%s",
1594                         sys_getppid(),
1595                         tsk->pid,
1596                         from_kuid(&init_user_ns, audit_get_loginuid(tsk)),
1597                         from_kuid(&init_user_ns, cred->uid),
1598                         from_kgid(&init_user_ns, cred->gid),
1599                         from_kuid(&init_user_ns, cred->euid),
1600                         from_kuid(&init_user_ns, cred->suid),
1601                         from_kuid(&init_user_ns, cred->fsuid),
1602                         from_kgid(&init_user_ns, cred->egid),
1603                         from_kgid(&init_user_ns, cred->sgid),
1604                         from_kgid(&init_user_ns, cred->fsgid),
1605                         audit_get_sessionid(tsk), tty);
1606
1607        get_task_comm(name, tsk);
1608        audit_log_format(ab, " comm=");
1609        audit_log_untrustedstring(ab, name);
1610
1611        if (mm) {
1612                down_read(&mm->mmap_sem);
1613                if (mm->exe_file)
1614                        audit_log_d_path(ab, " exe=", &mm->exe_file->f_path);
1615                up_read(&mm->mmap_sem);
1616        }
1617        audit_log_task_context(ab);
1618}
1619EXPORT_SYMBOL(audit_log_task_info);
1620
1621/**
1622 * audit_log_link_denied - report a link restriction denial
1623 * @operation: specific link opreation
1624 * @link: the path that triggered the restriction
1625 */
1626void audit_log_link_denied(const char *operation, struct path *link)
1627{
1628        struct audit_buffer *ab;
1629        struct audit_names *name;
1630
1631        name = kzalloc(sizeof(*name), GFP_NOFS);
1632        if (!name)
1633                return;
1634
1635        /* Generate AUDIT_ANOM_LINK with subject, operation, outcome. */
1636        ab = audit_log_start(current->audit_context, GFP_KERNEL,
1637                             AUDIT_ANOM_LINK);
1638        if (!ab)
1639                goto out;
1640        audit_log_format(ab, "op=%s", operation);
1641        audit_log_task_info(ab, current);
1642        audit_log_format(ab, " res=0");
1643        audit_log_end(ab);
1644
1645        /* Generate AUDIT_PATH record with object. */
1646        name->type = AUDIT_TYPE_NORMAL;
1647        audit_copy_inode(name, link->dentry, link->dentry->d_inode);
1648        audit_log_name(current->audit_context, name, link, 0, NULL);
1649out:
1650        kfree(name);
1651}
1652
1653/**
1654 * audit_log_end - end one audit record
1655 * @ab: the audit_buffer
1656 *
1657 * The netlink_* functions cannot be called inside an irq context, so
1658 * the audit buffer is placed on a queue and a tasklet is scheduled to
1659 * remove them from the queue outside the irq context.  May be called in
1660 * any context.
1661 */
1662void audit_log_end(struct audit_buffer *ab)
1663{
1664        if (!ab)
1665                return;
1666        if (!audit_rate_check()) {
1667                audit_log_lost("rate limit exceeded");
1668        } else {
1669                struct nlmsghdr *nlh = nlmsg_hdr(ab->skb);
1670                nlh->nlmsg_len = ab->skb->len - NLMSG_HDRLEN;
1671
1672                if (audit_pid) {
1673                        skb_queue_tail(&audit_skb_queue, ab->skb);
1674                        wake_up_interruptible(&kauditd_wait);
1675                } else {
1676                        audit_printk_skb(ab->skb);
1677                }
1678                ab->skb = NULL;
1679        }
1680        audit_buffer_free(ab);
1681}
1682
1683/**
1684 * audit_log - Log an audit record
1685 * @ctx: audit context
1686 * @gfp_mask: type of allocation
1687 * @type: audit message type
1688 * @fmt: format string to use
1689 * @...: variable parameters matching the format string
1690 *
1691 * This is a convenience function that calls audit_log_start,
1692 * audit_log_vformat, and audit_log_end.  It may be called
1693 * in any context.
1694 */
1695void audit_log(struct audit_context *ctx, gfp_t gfp_mask, int type,
1696               const char *fmt, ...)
1697{
1698        struct audit_buffer *ab;
1699        va_list args;
1700
1701        ab = audit_log_start(ctx, gfp_mask, type);
1702        if (ab) {
1703                va_start(args, fmt);
1704                audit_log_vformat(ab, fmt, args);
1705                va_end(args);
1706                audit_log_end(ab);
1707        }
1708}
1709
1710#ifdef CONFIG_SECURITY
1711/**
1712 * audit_log_secctx - Converts and logs SELinux context
1713 * @ab: audit_buffer
1714 * @secid: security number
1715 *
1716 * This is a helper function that calls security_secid_to_secctx to convert
1717 * secid to secctx and then adds the (converted) SELinux context to the audit
1718 * log by calling audit_log_format, thus also preventing leak of internal secid
1719 * to userspace. If secid cannot be converted audit_panic is called.
1720 */
1721void audit_log_secctx(struct audit_buffer *ab, u32 secid)
1722{
1723        u32 len;
1724        char *secctx;
1725
1726        if (security_secid_to_secctx(secid, &secctx, &len)) {
1727                audit_panic("Cannot convert secid to context");
1728        } else {
1729                audit_log_format(ab, " obj=%s", secctx);
1730                security_release_secctx(secctx, len);
1731        }
1732}
1733EXPORT_SYMBOL(audit_log_secctx);
1734#endif
1735
1736EXPORT_SYMBOL(audit_log_start);
1737EXPORT_SYMBOL(audit_log_end);
1738EXPORT_SYMBOL(audit_log_format);
1739EXPORT_SYMBOL(audit_log);
1740
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