/* audit.c -- Auditing support -*- linux-c -*-
* Gateway between the kernel (e.g., selinux) and the user-space audit daemon.
* System-call specific features have moved to auditsc.c
*
* Copyright 2003-2004 Red Hat Inc., Durham, North Carolina.
* All Rights Reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* Written by Rickard E. (Rik) Faith <faith@redhat.com>
*
* Goals: 1) Integrate fully with SELinux.
* 2) Minimal run-time overhead:
* a) Minimal when syscall auditing is disabled (audit_enable=0).
* b) Small when syscall auditing is enabled and no audit record
* is generated (defer as much work as possible to record
* generation time):
* i) context is allocated,
* ii) names from getname are stored without a copy, and
* iii) inode information stored from path_lookup.
* 3) Ability to disable syscall auditing at boot time (audit=0).
* 4) Usable by other parts of the kernel (if audit_log* is called,
* then a syscall record will be generated automatically for the
* current syscall).
* 5) Netlink interface to user-space.
* 6) Support low-overhead kernel-based filtering to minimize the
* information that must be passed to user-space.
*
* Example user-space utilities: http://people.redhat.com/faith/audit/
*/
#include <linux/init.h>
#include <asm/atomic.h>
#include <asm/types.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/audit.h>
#include <net/sock.h>
#include <linux/skbuff.h>
#include <linux/netlink.h>
/* No auditing will take place until audit_initialized != 0.
* (Initialization happens after skb_init is called.) */
static int audit_initialized;
/* No syscall auditing will take place unless audit_enabled != 0. */
int audit_enabled;
/* Default state when kernel boots without any parameters. */
static int audit_default;
/* If auditing cannot proceed, audit_failure selects what happens. */
static int audit_failure = AUDIT_FAIL_PRINTK;
/* If audit records are to be written to the netlink socket, audit_pid
* contains the (non-zero) pid. */
static int audit_pid;
/* If audit_limit is non-zero, limit the rate of sending audit records
* to that number per second. This prevents DoS attacks, but results in
* audit records being dropped. */
static int audit_rate_limit;
/* Number of outstanding audit_buffers allowed. */
static int audit_backlog_limit = 64;
static atomic_t audit_backlog = ATOMIC_INIT(0);
/* Records can be lost in several ways:
0) [suppressed in audit_alloc]
1) out of memory in audit_log_start [kmalloc of struct audit_buffer]
2) out of memory in audit_log_move [alloc_skb]
3) suppressed due to audit_rate_limit
4) suppressed due to audit_backlog_limit
*/
static atomic_t audit_lost = ATOMIC_INIT(0);
/* The netlink socket. */
static struct sock *audit_sock;
/* There are two lists of audit buffers. The txlist contains audit
* buffers that cannot be sent immediately to the netlink device because
* we are in an irq context (these are sent later in a tasklet).
*
* The second list is a list of pre-allocated audit buffers (if more
* than AUDIT_MAXFREE are in use, the audit buffer is freed instead of
* being placed on the freelist). */
static DEFINE_SPINLOCK(audit_txlist_lock);
static DEFINE_SPINLOCK(audit_freelist_lock);
static int audit_freelist_count = 0;
static LIST_HEAD(audit_txlist);
static LIST_HEAD(audit_freelist);
/* There are three lists of rules -- one to search at task creation
* time, one to search at syscall entry time, and another to search at
* syscall exit time. */
static LIST_HEAD(audit_tsklist);
static LIST_HEAD(audit_entlist);
static LIST_HEAD(audit_extlist);
/* The netlink socket is only to be read by 1 CPU, which lets us assume
* that list additions and deletions never happen simultaneiously in
* auditsc.c */
static DECLARE_MUTEX(audit_netlink_sem);
/* AUDIT_BUFSIZ is the size of the temporary buffer used for formatting
* audit records. Since printk uses a 1024 byte buffer, this buffer
* should be at least that large. */
#define AUDIT_BUFSIZ 1024
/* AUDIT_MAXFREE is the number of empty audit_buffers we keep on the
* audit_freelist. Doing so eliminates many kmalloc/kfree calls. */
#define AUDIT_MAXFREE (2*NR_CPUS)
/* The audit_buffer is used when formatting an audit record. The caller
* locks briefly to get the record off the freelist or to allocate the
* buffer, and locks briefly to send the buffer to the netlink layer or
* to place it on a transmit queue. Multiple audit_buffers can be in
* use simultaneously. */
struct audit_buffer {
struct list_head list;
struct sk_buff_head sklist; /* formatted skbs ready to send */
struct audit_context *ctx; /* NULL or associated context */
int len; /* used area of tmp */
char tmp[AUDIT_BUFSIZ];
/* Pointer to header and contents */
struct nlmsghdr *nlh;
int total;
int type;
int pid;
int count; /* Times requeued */
};
void audit_set_type(struct audit_buffer *ab, int type)
{
ab->type = type;
}
struct audit_entry {
struct list_head list;
struct audit_rule rule;
};
static void audit_log_end_irq(struct audit_buffer *ab);
static void audit_log_end_fast(struct audit_buffer *ab);
static void audit_panic(const char *message)
{
switch (audit_failure)
{
case AUDIT_FAIL_SILENT:
break;
case AUDIT_FAIL_PRINTK:
printk(KERN_ERR "audit: %s\n", message);
break;
case AUDIT_FAIL_PANIC:
panic("audit: %s\n", message);
break;
}
}
static inline int audit_rate_check(void)
{
static unsigned long last_check = 0;
static int messages = 0;
static DEFINE_SPINLOCK(lock);
unsigned long flags;
unsigned long now;
unsigned long elapsed;
int retval = 0;
if (!audit_rate_limit) return 1;
spin_lock_irqsave(&lock, flags);
if (++messages < audit_rate_limit) {
retval = 1;
} else {
now = jiffies;
elapsed = now - last_check;
if (elapsed > HZ) {
last_check = now;
messages = 0;
retval = 1;
}
}
spin_unlock_irqrestore(&lock, flags);
return retval;
}
/* Emit at least 1 message per second, even if audit_rate_check is
* throttling. */
void audit_log_lost(const char *message)
{
static unsigned long last_msg = 0;
static DEFINE_SPINLOCK(lock);
unsigned long flags;
unsigned long now;
int print;
atomic_inc(&audit_lost);
print = (audit_failure == AUDIT_FAIL_PANIC || !audit_rate_limit);
if (!print) {
spin_lock_irqsave(&lock, flags);
now = jiffies;
if (now - last_msg > HZ) {
print = 1;
last_msg = now;
}
spin_unlock_irqrestore(&lock, flags);
}
if (print) {
printk(KERN_WARNING
"audit: audit_lost=%d audit_backlog=%d"
" audit_rate_limit=%d audit_backlog_limit=%d\n",
atomic_read(&audit_lost),
atomic_read(&audit_backlog),
audit_rate_limit,
audit_backlog_limit);
audit_panic(message);
}
}
static int audit_set_rate_limit(int limit)
{
int old = audit_rate_limit;
audit_rate_limit = limit;
audit_log(current->audit_context, "audit_rate_limit=%d old=%d",
audit_rate_limit, old);
return old;
}
static int audit_set_backlog_limit(int limit)
{
int old = audit_backlog_limit;
audit_backlog_limit = limit;
audit_log(current->audit_context, "audit_backlog_limit=%d old=%d",
audit_backlog_limit, old);
return old;
}
static int audit_set_enabled(int state)
{
int old = audit_enabled;
if (state != 0 && state != 1)
return -EINVAL;
audit_enabled = state;
audit_log(current->audit_context, "audit_enabled=%d old=%d",
audit_enabled, old);
return old;
}
static int audit_set_failure(int state)
{
int old = audit_failure;
if (state != AUDIT_FAIL_SILENT
&& state != AUDIT_FAIL_PRINTK
&& state != AUDIT_FAIL_PANIC)
return -EINVAL;
audit_failure = state;
audit_log(current->audit_context, "audit_failure=%d old=%d",
audit_failure, old);
return old;
}
#ifdef CONFIG_NET
void audit_send_reply(int pid, int seq, int type, int done, int multi,
void *payload, int size)
{
struct sk_buff *skb;
struct nlmsghdr *nlh;
int len = NLMSG_SPACE(size);
void *data;
int flags = multi ? NLM_F_MULTI : 0;
int t = done ? NLMSG_DONE : type;
skb = alloc_skb(len, GFP_KERNEL);
if (!skb)
goto nlmsg_failure;
nlh = NLMSG_PUT(skb, pid, seq, t, len - sizeof(*nlh));
nlh->nlmsg_flags = flags;
data = NLMSG_DATA(nlh);
memcpy(data, payload, size);
netlink_unicast(audit_sock, skb, pid, MSG_DONTWAIT);
return;
nlmsg_failure: /* Used by NLMSG_PUT */
if (skb)
kfree_skb(skb);
}
/*
* Check for appropriate CAP_AUDIT_ capabilities on incoming audit
* control messages.
*/
static int audit_netlink_ok(kernel_cap_t eff_cap, u16 msg_type)
{
int err = 0;
switch (msg_type) {
case AUDIT_GET:
case AUDIT_LIST:
case AUDIT_SET:
case AUDIT_ADD:
case AUDIT_DEL:
if (!cap_raised(eff_cap, CAP_AUDIT_CONTROL))
err = -EPERM;
break;
case AUDIT_USER:
if (!cap_raised(eff_cap, CAP_AUDIT_WRITE))
err = -EPERM;
break;
default: /* bad msg */
err = -EINVAL;
}
return err;
}
static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
{
u32 uid, pid, seq;
void *data;
struct audit_status *status_get, status_set;
int err;
struct audit_buffer *ab;
u16 msg_type = nlh->nlmsg_type;
err = audit_netlink_ok(NETLINK_CB(skb).eff_cap, msg_type);
if (err)
return err;
pid = NETLINK_CREDS(skb)->pid;
uid = NETLINK_CREDS(skb)->uid;
seq = nlh->nlmsg_seq;
data = NLMSG_DATA(nlh);
switch (msg_type) {
case AUDIT_GET:
status_set.enabled = audit_enabled;
status_set.failure = audit_failure;
status_set.pid = audit_pid;
status_set.rate_limit = audit_rate_limit;
status_set.backlog_limit = audit_backlog_limit;
status_set.lost = atomic_read(&audit_lost);
status_set.backlog = atomic_read(&audit_backlog);
audit_send_reply(NETLINK_CB(skb).pid, seq, AUDIT_GET, 0, 0,
&status_set, sizeof(status_set));
break;
case AUDIT_SET:
if (nlh->nlmsg_len < sizeof(struct audit_status))
return -EINVAL;
status_get = (struct audit_status *)data;
if (status_get->mask & AUDIT_STATUS_ENABLED) {
err = audit_set_enabled(status_get->enabled);
if (err < 0) return err;
}
if (status_get->mask & AUDIT_STATUS_FAILURE) {
err = audit_set_failure(status_get->failure);
if (err < 0) return err;
}
if (status_get->mask & AUDIT_STATUS_PID) {
int old = audit_pid;
audit_pid = status_get->pid;
audit_log(current->audit_context,
"audit_pid=%d old=%d", audit_pid, old);
}
if (status_get->mask & AUDIT_STATUS_RATE_LIMIT)
audit_set_rate_limit(status_get->rate_limit);
if (status_get->mask & AUDIT_STATUS_BACKLOG_LIMIT)
audit_set_backlog_limit(status_get->backlog_limit);
break;
case AUDIT_USER:
ab = audit_log_start(NULL);
if (!ab)
break; /* audit_panic has been called */
audit_log_format(ab,
"user pid=%d uid=%d length=%d msg='%.1024s'",
pid, uid,
(int)(nlh->nlmsg_len
- ((char *)data - (char *)nlh)),
(char *)data);
ab->type = AUDIT_USER;
ab->pid = pid;
audit_log_end(ab);
break;
case AUDIT_ADD:
case AUDIT_DEL:
if (nlh->nlmsg_len < sizeof(struct audit_rule))
return -EINVAL;
/* fallthrough */
case AUDIT_LIST:
#ifdef CONFIG_AUDITSYSCALL
err = audit_receive_filter(nlh->nlmsg_type, NETLINK_CB(skb).pid,
uid, seq, data);
#else
err = -EOPNOTSUPP;
#endif
break;
default:
err = -EINVAL;
break;
}
return err < 0 ? err : 0;
}
/* Get message from skb (based on rtnetlink_rcv_skb). Each message is
* processed by audit_receive_msg. Malformed skbs with wrong length are
* discarded silently. */
static void audit_receive_skb(struct sk_buff *skb)
{
int err;
struct nlmsghdr *nlh;
u32 rlen;
while (skb->len >= NLMSG_SPACE(0)) {
nlh = (struct nlmsghdr *)skb->data;
if (nlh->nlmsg_len < sizeof(*nlh) || skb->len < nlh->nlmsg_len)
return;
rlen = NLMSG_ALIGN(nlh->nlmsg_len);
if (rlen > skb->len)
rlen = skb->len;
if ((err = audit_receive_msg(skb, nlh))) {
netlink_ack(skb, nlh, err);
} else if (nlh->nlmsg_flags & NLM_F_ACK)
netlink_ack(skb, nlh, 0);
skb_pull(skb, rlen);
}
}
/* Receive messages from netlink socket. */
static void audit_receive(struct sock *sk, int length)
{
struct sk_buff *skb;
unsigned int qlen;
down(&audit_netlink_sem);
for (qlen = skb_queue_len(&sk->sk_receive_queue); qlen; qlen--) {
skb = skb_dequeue(&sk->sk_receive_queue);
audit_receive_skb(skb);
kfree_skb(skb);
}
up(&audit_netlink_sem);
}
/* Move data from tmp buffer into an skb. This is an extra copy, and
* that is unfortunate. However, the copy will only occur when a record
* is being written to user space, which is already a high-overhead
* operation. (Elimination of the copy is possible, for example, by
* writing directly into a pre-allocated skb, at the cost of wasting
* memory. */
static void audit_log_move(struct audit_buffer *ab)
{
struct sk_buff *skb;
char *start;
int extra = ab->nlh ? 0 : NLMSG_SPACE(0);
/* possible resubmission */
if (ab->len == 0)
return;
skb = skb_peek(&ab->sklist);
if (!skb || skb_tailroom(skb) <= ab->len + extra) {
skb = alloc_skb(2 * ab->len + extra, GFP_ATOMIC);
if (!skb) {
ab->len = 0; /* Lose information in ab->tmp */
audit_log_lost("out of memory in audit_log_move");
return;
}
__skb_queue_tail(&ab->sklist, skb);
if (!ab->nlh)
ab->nlh = (struct nlmsghdr *)skb_put(skb,
NLMSG_SPACE(0));
}
start = skb_put(skb, ab->len);
memcpy(start, ab->tmp, ab->len);
ab->len = 0;
}
/* Iterate over the skbuff in the audit_buffer, sending their contents
* to user space. */
static inline int audit_log_drain(struct audit_buffer *ab)
{
struct sk_buff *skb;
while ((skb = skb_dequeue(&ab->sklist))) {
int retval = 0;
if (audit_pid) {
if (ab->nlh) {
ab->nlh->nlmsg_len = ab->total;
ab->nlh->nlmsg_type = ab->type;
ab->nlh->nlmsg_flags = 0;
ab->nlh->nlmsg_seq = 0;
ab->nlh->nlmsg_pid = ab->pid;
}
skb_get(skb); /* because netlink_* frees */
retval = netlink_unicast(audit_sock, skb, audit_pid,
MSG_DONTWAIT);
}
if (retval == -EAGAIN && ab->count < 5) {
++ab->count;
skb_queue_tail(&ab->sklist, skb);
audit_log_end_irq(ab);
return 1;
}
if (retval < 0) {
if (retval == -ECONNREFUSED) {
printk(KERN_ERR
"audit: *NO* daemon at audit_pid=%d\n",
audit_pid);
audit_pid = 0;
} else
audit_log_lost("netlink socket too busy");
}
if (!audit_pid) { /* No daemon */
int offset = ab->nlh ? NLMSG_SPACE(0) : 0;
int len = skb->len - offset;
printk(KERN_ERR "%*.*s\n",
len, len, skb->data + offset);
}
kfree_skb(skb);
ab->nlh = NULL;
}
return 0;
}
/* Initialize audit support at boot time. */
static int __init audit_init(void)
{
printk(KERN_INFO "audit: initializing netlink socket (%s)\n",
audit_default ? "enabled" : "disabled");
audit_sock = netlink_kernel_create(NETLINK_AUDIT, audit_receive);
if (!audit_sock)
audit_panic("cannot initialize netlink socket");
audit_initialized = 1;
audit_enabled = audit_default;
audit_log(NULL, "initialized");
return 0;
}
#else
/* Without CONFIG_NET, we have no skbuffs. For now, print what we have
* in the buffer. */
static void audit_log_move(struct audit_buffer *ab)
{
printk(KERN_ERR "%*.*s\n", ab->len, ab->len, ab->tmp);
ab->len = 0;
}
static inline int audit_log_drain(struct audit_buffer *ab)
{
return 0;
}
/* Initialize audit support at boot time. */
int __init audit_init(void)
{
printk(KERN_INFO "audit: initializing WITHOUT netlink support\n");
audit_sock = NULL;
audit_pid = 0;
audit_initialized = 1;
audit_enabled = audit_default;
audit_log(NULL, "initialized");
return 0;
}
#endif
__initcall(audit_init);
/* Process kernel command-line parameter at boot time. audit=0 or audit=1. */
static int __init audit_enable(char *str)
{
audit_default = !!simple_strtol(str, NULL, 0);
printk(KERN_INFO "audit: %s%s\n",
audit_default ? "enabled" : "disabled",
audit_initialized ? "" : " (after initialization)");
if (audit_initialized)
audit_enabled = audit_default;
return 0;
}
__setup("audit=", audit_enable);
/* Obtain an audit buffer. This routine does locking to obtain the
* audit buffer, but then no locking is required for calls to
* audit_log_*format. If the tsk is a task that is currently in a
* syscall, then the syscall is marked as auditable and an audit record
* will be written at syscall exit. If there is no associated task, tsk
* should be NULL. */
struct audit_buffer *audit_log_start(struct audit_context *ctx)
{
struct audit_buffer *ab = NULL;
unsigned long flags;
struct timespec t;
int serial = 0;
if (!audit_initialized)
return NULL;
if (audit_backlog_limit
&& atomic_read(&audit_backlog) > audit_backlog_limit) {
if (audit_rate_check())
printk(KERN_WARNING
"audit: audit_backlog=%d > "
"audit_backlog_limit=%d\n",
atomic_read(&audit_backlog),
audit_backlog_limit);
audit_log_lost("backlog limit exceeded");
return NULL;
}
spin_lock_irqsave(&audit_freelist_lock, flags);
if (!list_empty(&audit_freelist)) {
ab = list_entry(audit_freelist.next,
struct audit_buffer, list);
list_del(&ab->list);
--audit_freelist_count;
}
spin_unlock_irqrestore(&audit_freelist_lock, flags);
if (!ab)
ab = kmalloc(sizeof(*ab), GFP_ATOMIC);
if (!ab) {
audit_log_lost("out of memory in audit_log_start");
return NULL;
}
atomic_inc(&audit_backlog);
skb_queue_head_init(&ab->sklist);
ab->ctx = ctx;
ab->len = 0;
ab->nlh = NULL;
ab->total = 0;
ab->type = AUDIT_KERNEL;
ab->pid = 0;
ab->count = 0;
#ifdef CONFIG_AUDITSYSCALL
if (ab->ctx)
audit_get_stamp(ab->ctx, &t, &serial);
else
#endif
t = CURRENT_TIME;
audit_log_format(ab, "audit(%lu.%03lu:%u): ",
t.tv_sec, t.tv_nsec/1000000, serial);
return ab;
}
/* Format an audit message into the audit buffer. If there isn't enough
* room in the audit buffer, more room will be allocated and vsnprint
* will be called a second time. Currently, we assume that a printk
* can't format message larger than 1024 bytes, so we don't either. */
static void audit_log_vformat(struct audit_buffer *ab, const char *fmt,
va_list args)
{
int len, avail;
if (!ab)
return;
avail = sizeof(ab->tmp) - ab->len;
if (avail <= 0) {
audit_log_move(ab);
avail = sizeof(ab->tmp) - ab->len;
}
len = vsnprintf(ab->tmp + ab->len, avail, fmt, args);
if (len >= avail) {
/* The printk buffer is 1024 bytes long, so if we get
* here and AUDIT_BUFSIZ is at least 1024, then we can
* log everything that printk could have logged. */
audit_log_move(ab);
avail = sizeof(ab->tmp) - ab->len;
len = vsnprintf(ab->tmp + ab->len, avail, fmt, args);
}
ab->len += (len < avail) ? len : avail;
ab->total += (len < avail) ? len : avail;
}
/* Format a message into the audit buffer. All the work is done in
* audit_log_vformat. */
void audit_log_format(struct audit_buffer *ab, const char *fmt, ...)
{
va_list args;
if (!ab)
return;
va_start(args, fmt);
audit_log_vformat(ab, fmt, args);
va_end(args);
}
/* This is a helper-function to print the d_path without using a static
* buffer or allocating another buffer in addition to the one in
* audit_buffer. */
void audit_log_d_path(struct audit_buffer *ab, const char *prefix,
struct dentry *dentry, struct vfsmount *vfsmnt)
{
char *p;
int len, avail;
if (prefix) audit_log_format(ab, " %s", prefix);
if (ab->len > 128)
audit_log_move(ab);
avail = sizeof(ab->tmp) - ab->len;
p = d_path(dentry, vfsmnt, ab->tmp + ab->len, avail);
if (IS_ERR(p)) {
/* FIXME: can we save some information here? */
audit_log_format(ab, "<toolong>");
} else {
/* path isn't at start of buffer */
len = (ab->tmp + sizeof(ab->tmp) - 1) - p;
memmove(ab->tmp + ab->len, p, len);
ab->len += len;
ab->total += len;
}
}
/* Remove queued messages from the audit_txlist and send them to userspace. */
static void audit_tasklet_handler(unsigned long arg)
{
LIST_HEAD(list);
struct audit_buffer *ab;
unsigned long flags;
spin_lock_irqsave(&audit_txlist_lock, flags);
list_splice_init(&audit_txlist, &list);
spin_unlock_irqrestore(&audit_txlist_lock, flags);
while (!list_empty(&list)) {
ab = list_entry(list.next, struct audit_buffer, list);
list_del(&ab->list);
audit_log_end_fast(ab);
}
}
static DECLARE_TASKLET(audit_tasklet, audit_tasklet_handler, 0);
/* The netlink_* functions cannot be called inside an irq context, so
* the audit buffer is places on a queue and a tasklet is scheduled to
* remove them from the queue outside the irq context. May be called in
* any context. */
static void audit_log_end_irq(struct audit_buffer *ab)
{
unsigned long flags;
if (!ab)
return;
spin_lock_irqsave(&audit_txlist_lock, flags);
list_add_tail(&ab->list, &audit_txlist);
spin_unlock_irqrestore(&audit_txlist_lock, flags);
tasklet_schedule(&audit_tasklet);
}
/* Send the message in the audit buffer directly to user space. May not
* be called in an irq context. */
static void audit_log_end_fast(struct audit_buffer *ab)
{
unsigned long flags;
BUG_ON(in_irq());
if (!ab)
return;
if (!audit_rate_check()) {
audit_log_lost("rate limit exceeded");
} else {
audit_log_move(ab);
if (audit_log_drain(ab))
return;
}
atomic_dec(&audit_backlog);
spin_lock_irqsave(&audit_freelist_lock, flags);
if (++audit_freelist_count > AUDIT_MAXFREE)
kfree(ab);
else
list_add(&ab->list, &audit_freelist);
spin_unlock_irqrestore(&audit_freelist_lock, flags);
}
/* Send or queue the message in the audit buffer, depending on the
* current context. (A convenience function that may be called in any
* context.) */
void audit_log_end(struct audit_buffer *ab)
{
if (in_irq())
audit_log_end_irq(ab);
else
audit_log_end_fast(ab);
}
/* Log an audit record. This is a convenience function that calls
* audit_log_start, audit_log_vformat, and audit_log_end. It may be
* called in any context. */
void audit_log(struct audit_context *ctx, const char *fmt, ...)
{
struct audit_buffer *ab;
va_list args;
ab = audit_log_start(ctx);
if (ab) {
va_start(args, fmt);
audit_log_vformat(ab, fmt, args);
va_end(args);
audit_log_end(ab);
}
}
