1 files changed, 79 insertions, 42 deletions

diff --git a/kernel/audit.c b/kernel/audit.c
index 121d37e700a6..9bc0b0301198 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -321,7 +321,6 @@ static inline int audit_rate_check(void)
 	static DEFINE_SPINLOCK(lock);
 	unsigned long		flags;
 	unsigned long		now;
-	unsigned long		elapsed;
 	int			retval	   = 0;
 
 	if (!audit_rate_limit) return 1;
@@ -330,9 +329,8 @@ static inline int audit_rate_check(void)
 	if (++messages < audit_rate_limit) {
 		retval = 1;
 	} else {
-		now     = jiffies;
-		elapsed = now - last_check;
-		if (elapsed > HZ) {
+		now = jiffies;
+		if (time_after(now, last_check + HZ)) {
 			last_check = now;
 			messages   = 0;
 			retval     = 1;
@@ -366,7 +364,7 @@ void audit_log_lost(const char *message)
 	if (!print) {
 		spin_lock_irqsave(&lock, flags);
 		now = jiffies;
-		if (now - last_msg > HZ) {
+		if (time_after(now, last_msg + HZ)) {
 			print = 1;
 			last_msg = now;
 		}
@@ -541,20 +539,22 @@ static void kauditd_printk_skb(struct sk_buff *skb)
 /**
  * kauditd_rehold_skb - Handle a audit record send failure in the hold queue
  * @skb: audit record
+ * @error: error code (unused)
  *
  * Description:
  * This should only be used by the kauditd_thread when it fails to flush the
  * hold queue.
  */
-static void kauditd_rehold_skb(struct sk_buff *skb)
+static void kauditd_rehold_skb(struct sk_buff *skb, __always_unused int error)
 {
-	/* put the record back in the queue at the same place */
-	skb_queue_head(&audit_hold_queue, skb);
+	/* put the record back in the queue */
+	skb_queue_tail(&audit_hold_queue, skb);
 }
 
 /**
  * kauditd_hold_skb - Queue an audit record, waiting for auditd
  * @skb: audit record
+ * @error: error code
  *
  * Description:
  * Queue the audit record, waiting for an instance of auditd.  When this
@@ -564,19 +564,31 @@ static void kauditd_rehold_skb(struct sk_buff *skb)
  * and queue it, if we have room.  If we want to hold on to the record, but we
  * don't have room, record a record lost message.
  */
-static void kauditd_hold_skb(struct sk_buff *skb)
+static void kauditd_hold_skb(struct sk_buff *skb, int error)
 {
 	/* at this point it is uncertain if we will ever send this to auditd so
 	 * try to send the message via printk before we go any further */
 	kauditd_printk_skb(skb);
 
 	/* can we just silently drop the message? */
-	if (!audit_default) {
-		kfree_skb(skb);
-		return;
+	if (!audit_default)
+		goto drop;
+
+	/* the hold queue is only for when the daemon goes away completely,
+	 * not -EAGAIN failures; if we are in a -EAGAIN state requeue the
+	 * record on the retry queue unless it's full, in which case drop it
+	 */
+	if (error == -EAGAIN) {
+		if (!audit_backlog_limit ||
+		    skb_queue_len(&audit_retry_queue) < audit_backlog_limit) {
+			skb_queue_tail(&audit_retry_queue, skb);
+			return;
+		}
+		audit_log_lost("kauditd retry queue overflow");
+		goto drop;
 	}
 
-	/* if we have room, queue the message */
+	/* if we have room in the hold queue, queue the message */
 	if (!audit_backlog_limit ||
 	    skb_queue_len(&audit_hold_queue) < audit_backlog_limit) {
 		skb_queue_tail(&audit_hold_queue, skb);
@@ -585,24 +597,32 @@ static void kauditd_hold_skb(struct sk_buff *skb)
 
 	/* we have no other options - drop the message */
 	audit_log_lost("kauditd hold queue overflow");
+drop:
 	kfree_skb(skb);
 }
 
 /**
  * kauditd_retry_skb - Queue an audit record, attempt to send again to auditd
  * @skb: audit record
+ * @error: error code (unused)
  *
  * Description:
  * Not as serious as kauditd_hold_skb() as we still have a connected auditd,
  * but for some reason we are having problems sending it audit records so
  * queue the given record and attempt to resend.
  */
-static void kauditd_retry_skb(struct sk_buff *skb)
+static void kauditd_retry_skb(struct sk_buff *skb, __always_unused int error)
 {
-	/* NOTE: because records should only live in the retry queue for a
-	 * short period of time, before either being sent or moved to the hold
-	 * queue, we don't currently enforce a limit on this queue */
-	skb_queue_tail(&audit_retry_queue, skb);
+	if (!audit_backlog_limit ||
+	    skb_queue_len(&audit_retry_queue) < audit_backlog_limit) {
+		skb_queue_tail(&audit_retry_queue, skb);
+		return;
+	}
+
+	/* we have to drop the record, send it via printk as a last effort */
+	kauditd_printk_skb(skb);
+	audit_log_lost("kauditd retry queue overflow");
+	kfree_skb(skb);
 }
 
 /**
@@ -640,7 +660,7 @@ static void auditd_reset(const struct auditd_connection *ac)
 	/* flush the retry queue to the hold queue, but don't touch the main
 	 * queue since we need to process that normally for multicast */
 	while ((skb = skb_dequeue(&audit_retry_queue)))
-		kauditd_hold_skb(skb);
+		kauditd_hold_skb(skb, -ECONNREFUSED);
 }
 
 /**
@@ -714,16 +734,18 @@ static int kauditd_send_queue(struct sock *sk, u32 portid,
 			      struct sk_buff_head *queue,
 			      unsigned int retry_limit,
 			      void (*skb_hook)(struct sk_buff *skb),
-			      void (*err_hook)(struct sk_buff *skb))
+			      void (*err_hook)(struct sk_buff *skb, int error))
 {
 	int rc = 0;
-	struct sk_buff *skb;
-	static unsigned int failed = 0;
+	struct sk_buff *skb = NULL;
+	struct sk_buff *skb_tail;
+	unsigned int failed = 0;
 
 	/* NOTE: kauditd_thread takes care of all our locking, we just use
 	 *       the netlink info passed to us (e.g. sk and portid) */
 
-	while ((skb = skb_dequeue(queue))) {
+	skb_tail = skb_peek_tail(queue);
+	while ((skb != skb_tail) && (skb = skb_dequeue(queue))) {
 		/* call the skb_hook for each skb we touch */
 		if (skb_hook)
 			(*skb_hook)(skb);
@@ -731,36 +753,34 @@ static int kauditd_send_queue(struct sock *sk, u32 portid,
 		/* can we send to anyone via unicast? */
 		if (!sk) {
 			if (err_hook)
-				(*err_hook)(skb);
+				(*err_hook)(skb, -ECONNREFUSED);
 			continue;
 		}
 
+retry:
 		/* grab an extra skb reference in case of error */
 		skb_get(skb);
 		rc = netlink_unicast(sk, skb, portid, 0);
 		if (rc < 0) {
-			/* fatal failure for our queue flush attempt? */
+			/* send failed - try a few times unless fatal error */
 			if (++failed >= retry_limit ||
 			    rc == -ECONNREFUSED || rc == -EPERM) {
-				/* yes - error processing for the queue */
 				sk = NULL;
 				if (err_hook)
-					(*err_hook)(skb);
-				if (!skb_hook)
-					goto out;
-				/* keep processing with the skb_hook */
+					(*err_hook)(skb, rc);
+				if (rc == -EAGAIN)
+					rc = 0;
+				/* continue to drain the queue */
 				continue;
 			} else
-				/* no - requeue to preserve ordering */
-				skb_queue_head(queue, skb);
+				goto retry;
 		} else {
-			/* it worked - drop the extra reference and continue */
+			/* skb sent - drop the extra reference and continue */
 			consume_skb(skb);
 			failed = 0;
 		}
 	}
 
-out:
 	return (rc >= 0 ? 0 : rc);
 }
 
@@ -1078,7 +1098,7 @@ static inline void audit_log_user_recv_msg(struct audit_buffer **ab,
 	audit_log_common_recv_msg(NULL, ab, msg_type);
 }
 
-int is_audit_feature_set(int i)
+static int is_audit_feature_set(int i)
 {
 	return af.features & AUDIT_FEATURE_TO_MASK(i);
 }
@@ -1368,7 +1388,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 						 str);
 			} else {
 				audit_log_format(ab, " data=");
-				if (data_len > 0 && str[data_len - 1] == '\0')
+				if (str[data_len - 1] == '\0')
 					data_len--;
 				audit_log_n_untrustedstring(ab, str, data_len);
 			}
@@ -1446,7 +1466,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 			if (err)
 				return err;
 		}
-		sig_data = kmalloc(sizeof(*sig_data) + len, GFP_KERNEL);
+		sig_data = kmalloc(struct_size(sig_data, ctx, len), GFP_KERNEL);
 		if (!sig_data) {
 			if (audit_sig_sid)
 				security_release_secctx(ctx, len);
@@ -1459,7 +1479,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 			security_release_secctx(ctx, len);
 		}
 		audit_send_reply(skb, seq, AUDIT_SIGNAL_INFO, 0, 0,
-				 sig_data, sizeof(*sig_data) + len);
+				 sig_data, struct_size(sig_data, ctx, len));
 		kfree(sig_data);
 		break;
 	case AUDIT_TTY_GET: {
@@ -1542,6 +1562,20 @@ static void audit_receive(struct sk_buff  *skb)
 		nlh = nlmsg_next(nlh, &len);
 	}
 	audit_ctl_unlock();
+
+	/* can't block with the ctrl lock, so penalize the sender now */
+	if (audit_backlog_limit &&
+	    (skb_queue_len(&audit_queue) > audit_backlog_limit)) {
+		DECLARE_WAITQUEUE(wait, current);
+
+		/* wake kauditd to try and flush the queue */
+		wake_up_interruptible(&kauditd_wait);
+
+		add_wait_queue_exclusive(&audit_backlog_wait, &wait);
+		set_current_state(TASK_UNINTERRUPTIBLE);
+		schedule_timeout(audit_backlog_wait_time);
+		remove_wait_queue(&audit_backlog_wait, &wait);
+	}
 }
 
 /* Log information about who is connecting to the audit multicast socket */
@@ -1609,7 +1643,8 @@ static int __net_init audit_net_init(struct net *net)
 		audit_panic("cannot initialize netlink socket in namespace");
 		return -ENOMEM;
 	}
-	aunet->sk->sk_sndtimeo = MAX_SCHEDULE_TIMEOUT;
+	/* limit the timeout in case auditd is blocked/stopped */
+	aunet->sk->sk_sndtimeo = HZ / 10;
 
 	return 0;
 }
@@ -1825,7 +1860,9 @@ struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
 	 *    task_tgid_vnr() since auditd_pid is set in audit_receive_msg()
 	 *    using a PID anchored in the caller's namespace
 	 * 2. generator holding the audit_cmd_mutex - we don't want to block
-	 *    while holding the mutex */
+	 *    while holding the mutex, although we do penalize the sender
+	 *    later in audit_receive() when it is safe to block
+	 */
 	if (!(auditd_test_task(current) || audit_ctl_owner_current())) {
 		long stime = audit_backlog_wait_time;
 
@@ -2132,7 +2169,7 @@ int audit_log_task_context(struct audit_buffer *ab)
 	int error;
 	u32 sid;
 
-	security_task_getsecid_subj(current, &sid);
+	security_current_getsecid_subj(&sid);
 	if (!sid)
 		return 0;
 
@@ -2353,7 +2390,7 @@ int audit_signal_info(int sig, struct task_struct *t)
 			audit_sig_uid = auid;
 		else
 			audit_sig_uid = uid;
-		security_task_getsecid_subj(current, &audit_sig_sid);
+		security_current_getsecid_subj(&audit_sig_sid);
 	}
 
 	return audit_signal_info_syscall(t);