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

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