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if (audit_initialized == AUDIT_INITIALIZED) {
audit_ever_enabled |= !!audit_default;
} else if (audit_initialized == AUDIT_UNINITIALIZED) {
printk(" (after initialization)");
} else {
printk(" (until reboot)");
static void audit_buffer_free(struct audit_buffer *ab)
{
unsigned long flags;
if (ab->skb)
kfree_skb(ab->skb);
spin_lock_irqsave(&audit_freelist_lock, flags);
if (audit_freelist_count > AUDIT_MAXFREE)
kfree(ab);
list_add(&ab->list, &audit_freelist);
spin_unlock_irqrestore(&audit_freelist_lock, flags);
}
static struct audit_buffer * audit_buffer_alloc(struct audit_context *ctx,
{
unsigned long flags;
struct audit_buffer *ab = 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_mask);
if (!ab)
ab->ctx = ctx;
ab->gfp_mask = gfp_mask;
ab->skb = nlmsg_new(AUDIT_BUFSIZ, gfp_mask);
if (!ab->skb)
goto nlmsg_failure;
nlh = NLMSG_NEW(ab->skb, 0, 0, type, 0, 0);
return ab;
nlmsg_failure: /* Used by NLMSG_NEW */
kfree_skb(ab->skb);
ab->skb = NULL;
err:
audit_buffer_free(ab);
return NULL;
/**
* audit_serial - compute a serial number for the audit record
*
* Compute a serial number for the audit record. Audit records are
* written to user-space as soon as they are generated, so a complete
* audit record may be written in several pieces. The timestamp of the
* record and this serial number are used by the user-space tools to
* determine which pieces belong to the same audit record. The
* (timestamp,serial) tuple is unique for each syscall and is live from
* syscall entry to syscall exit.
*
* NOTE: Another possibility is to store the formatted records off the
* audit context (for those records that have a context), and emit them
* all at syscall exit. However, this could delay the reporting of
* significant errors until syscall exit (or never, if the system
unsigned int audit_serial(void)
{
static unsigned int serial = 0;
unsigned long flags;
unsigned int ret;
spin_lock_irqsave(&serial_lock, flags);
ret = ++serial;
} while (unlikely(!ret));
spin_unlock_irqrestore(&serial_lock, flags);
static inline void audit_get_stamp(struct audit_context *ctx,
struct timespec *t, unsigned int *serial)
{
if (!ctx || !auditsc_get_stamp(ctx, t, serial)) {
*t = CURRENT_TIME;
*serial = audit_serial();
}
}
/* 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. */
/**
* audit_log_start - obtain an audit buffer
* @ctx: audit_context (may be NULL)
* @gfp_mask: type of allocation
* @type: audit message type
*
* Returns audit_buffer pointer on success or NULL on error.
*
* 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 task (ctx) 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, then
* task context (ctx) should be NULL.
*/
struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
{
struct audit_buffer *ab = NULL;
struct timespec t;
unsigned int uninitialized_var(serial);
int reserve;
unsigned long timeout_start = jiffies;
if (audit_initialized != AUDIT_INITIALIZED)
if (unlikely(audit_filter_type(type)))
return NULL;
if (gfp_mask & __GFP_WAIT)
reserve = 0;
else
reserve = 5; /* Allow atomic callers to go up to five
entries over the normal backlog limit */
while (audit_backlog_limit
&& skb_queue_len(&audit_skb_queue) > audit_backlog_limit + reserve) {
if (gfp_mask & __GFP_WAIT && audit_backlog_wait_time
&& time_before(jiffies, timeout_start + audit_backlog_wait_time)) {
/* Wait for auditd to drain the queue a little */
DECLARE_WAITQUEUE(wait, current);
set_current_state(TASK_INTERRUPTIBLE);
add_wait_queue(&audit_backlog_wait, &wait);
if (audit_backlog_limit &&
skb_queue_len(&audit_skb_queue) > audit_backlog_limit)
schedule_timeout(timeout_start + audit_backlog_wait_time - jiffies);
__set_current_state(TASK_RUNNING);
remove_wait_queue(&audit_backlog_wait, &wait);
continue;
if (audit_rate_check() && printk_ratelimit())
printk(KERN_WARNING
"audit: audit_backlog=%d > "
"audit_backlog_limit=%d\n",
skb_queue_len(&audit_skb_queue),
audit_backlog_limit);
audit_log_lost("backlog limit exceeded");
audit_backlog_wait_time = audit_backlog_wait_overflow;
wake_up(&audit_backlog_wait);
ab = audit_buffer_alloc(ctx, gfp_mask, type);
if (!ab) {
audit_log_lost("out of memory in audit_log_start");
return NULL;
}
audit_get_stamp(ab->ctx, &t, &serial);
audit_log_format(ab, "audit(%lu.%03lu:%u): ",
t.tv_sec, t.tv_nsec/1000000, serial);
return ab;
}
* audit_expand - expand skb in the audit buffer
* @extra: space to add at tail of the skb
*
* Returns 0 (no space) on failed expansion, or available space if
* successful.
*/
static inline int audit_expand(struct audit_buffer *ab, int extra)
int oldtail = skb_tailroom(skb);
int ret = pskb_expand_head(skb, 0, extra, ab->gfp_mask);
int newtail = skb_tailroom(skb);
if (ret < 0) {
audit_log_lost("out of memory in audit_expand");
skb->truesize += newtail - oldtail;
return newtail;
/*
* 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;
BUG_ON(!ab->skb);
skb = ab->skb;
avail = skb_tailroom(skb);
if (avail == 0) {
avail = audit_expand(ab, AUDIT_BUFSIZ);
len = vsnprintf(skb_tail_pointer(skb), 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. */
avail = audit_expand(ab,
max_t(unsigned, AUDIT_BUFSIZ, 1+len-avail));
len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args2);
if (len > 0)
skb_put(skb, len);
/**
* audit_log_format - format a message into the audit buffer.
* @ab: audit_buffer
* @fmt: format string
* @...: optional parameters matching @fmt string
*
* 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);
}
/**
* audit_log_hex - convert a buffer to hex and append it to the audit skb
* @ab: the audit_buffer
* @buf: buffer to convert to hex
* @len: length of @buf to be converted
*
* No return value; failure to expand is silently ignored.
*
* This function will take the passed buf and convert it into a string of
* ascii hex digits. The new string is placed onto the skb.
*/
void audit_log_n_hex(struct audit_buffer *ab, const unsigned char *buf,
int i, avail, new_len;
unsigned char *ptr;
struct sk_buff *skb;
static const unsigned char *hex = "0123456789ABCDEF";
BUG_ON(!ab->skb);
skb = ab->skb;
avail = skb_tailroom(skb);
new_len = len<<1;
if (new_len >= avail) {
/* Round the buffer request up to the next multiple */
new_len = AUDIT_BUFSIZ*(((new_len-avail)/AUDIT_BUFSIZ) + 1);
avail = audit_expand(ab, new_len);
if (!avail)
return;
}
ptr = skb_tail_pointer(skb);
for (i=0; i<len; i++) {
*ptr++ = hex[(buf[i] & 0xF0)>>4]; /* Upper nibble */
*ptr++ = hex[buf[i] & 0x0F]; /* Lower nibble */
}
*ptr = 0;
skb_put(skb, len << 1); /* new string is twice the old string */
/*
* Format a string of no more than slen characters into the audit buffer,
* enclosed in quote marks.
*/
void audit_log_n_string(struct audit_buffer *ab, const char *string,
size_t slen)
{
int avail, new_len;
unsigned char *ptr;
struct sk_buff *skb;
BUG_ON(!ab->skb);
skb = ab->skb;
avail = skb_tailroom(skb);
new_len = slen + 3; /* enclosing quotes + null terminator */
if (new_len > avail) {
avail = audit_expand(ab, new_len);
if (!avail)
return;
}
ptr = skb_tail_pointer(skb);
*ptr++ = '"';
memcpy(ptr, string, slen);
ptr += slen;
*ptr++ = '"';
*ptr = 0;
skb_put(skb, slen + 2); /* don't include null terminator */
}
/**
* audit_string_contains_control - does a string need to be logged in hex
* @string: string to be checked
* @len: max length of the string to check
*/
int audit_string_contains_control(const char *string, size_t len)
{
const unsigned char *p;
for (p = string; p < (const unsigned char *)string + len; p++) {
if (*p == '"' || *p < 0x21 || *p > 0x7e)
return 1;
}
return 0;
}
* audit_log_n_untrustedstring - log a string that may contain random characters
* @len: length of string (not including trailing null)
* @string: string to be logged
*
* This code will escape a string that is passed to it if the string
* contains a control character, unprintable character, double quote mark,
* or a space. Unescaped strings will start and end with a double quote mark.
* Strings that are escaped are printed in hex (2 digits per char).
*
* The caller specifies the number of characters in the string to log, which may
* or may not be the entire string.
void audit_log_n_untrustedstring(struct audit_buffer *ab, const char *string,
size_t len)
if (audit_string_contains_control(string, len))
audit_log_n_hex(ab, string, len);
audit_log_n_string(ab, string, len);
* audit_log_untrustedstring - log a string that may contain random characters
* @ab: audit_buffer
* @string: string to be logged
*
* Same as audit_log_n_untrustedstring(), except that strlen is used to
* determine string length.
*/
void audit_log_untrustedstring(struct audit_buffer *ab, const char *string)
audit_log_n_untrustedstring(ab, string, strlen(string));
/* This is a helper-function to print the escaped d_path */
void audit_log_d_path(struct audit_buffer *ab, const char *prefix,
if (prefix)
audit_log_format(ab, " %s", prefix);
/* We will allow 11 spaces for ' (deleted)' to be appended */
pathname = kmalloc(PATH_MAX+11, ab->gfp_mask);
if (!pathname) {
audit_log_string(ab, "<no_memory>");
p = d_path(path, pathname, PATH_MAX+11);
if (IS_ERR(p)) { /* Should never happen since we send PATH_MAX */
/* FIXME: can we save some information here? */
audit_log_string(ab, "<too_long>");
audit_log_untrustedstring(ab, p);
void audit_log_key(struct audit_buffer *ab, char *key)
{
audit_log_format(ab, " key=");
if (key)
audit_log_untrustedstring(ab, key);
else
audit_log_format(ab, "(null)");
}
/**
* audit_log_end - end one audit record
* @ab: the audit_buffer
*
* The netlink_* functions cannot be called inside an irq context, so
* the audit buffer is placed on a queue and a tasklet is scheduled to
* remove them from the queue outside the irq context. May be called in
void audit_log_end(struct audit_buffer *ab)
{
if (!ab)
return;
if (!audit_rate_check()) {
audit_log_lost("rate limit exceeded");
} else {
struct nlmsghdr *nlh = nlmsg_hdr(ab->skb);
nlh->nlmsg_len = ab->skb->len - NLMSG_SPACE(0);
if (audit_pid) {
skb_queue_tail(&audit_skb_queue, ab->skb);
wake_up_interruptible(&kauditd_wait);
} else {
audit_printk_skb(ab->skb);
ab->skb = NULL;
audit_buffer_free(ab);
/**
* audit_log - Log an audit record
* @ctx: audit context
* @gfp_mask: type of allocation
* @type: audit message type
* @fmt: format string to use
* @...: variable parameters matching the format string
*
* 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, gfp_t gfp_mask, int type,
const char *fmt, ...)
{
struct audit_buffer *ab;
va_list args;
ab = audit_log_start(ctx, gfp_mask, type);
if (ab) {
va_start(args, fmt);
audit_log_vformat(ab, fmt, args);
va_end(args);
audit_log_end(ab);
}
}
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#ifdef CONFIG_SECURITY
/**
* audit_log_secctx - Converts and logs SELinux context
* @ab: audit_buffer
* @secid: security number
*
* This is a helper function that calls security_secid_to_secctx to convert
* secid to secctx and then adds the (converted) SELinux context to the audit
* log by calling audit_log_format, thus also preventing leak of internal secid
* to userspace. If secid cannot be converted audit_panic is called.
*/
void audit_log_secctx(struct audit_buffer *ab, u32 secid)
{
u32 len;
char *secctx;
if (security_secid_to_secctx(secid, &secctx, &len)) {
audit_panic("Cannot convert secid to context");
} else {
audit_log_format(ab, " obj=%s", secctx);
security_release_secctx(secctx, len);
}
}
EXPORT_SYMBOL(audit_log_secctx);
#endif
lorenzo@gnu.org
committed
EXPORT_SYMBOL(audit_log_start);
EXPORT_SYMBOL(audit_log_end);
EXPORT_SYMBOL(audit_log_format);
EXPORT_SYMBOL(audit_log);