1 files changed, 41 insertions, 18 deletions

diff --git a/net/llc/af_llc.c b/net/llc/af_llc.c
index bcba579e292f..5cba9199c3c9 100644
--- a/net/llc/af_llc.c
+++ b/net/llc/af_llc.c
@@ -98,8 +98,16 @@ static inline u8 llc_ui_header_len(struct sock *sk, struct sockaddr_llc *addr)
 {
 	u8 rc = LLC_PDU_LEN_U;
 
-	if (addr->sllc_test || addr->sllc_xid)
+	if (addr->sllc_test)
 		rc = LLC_PDU_LEN_U;
+	else if (addr->sllc_xid)
+		/* We need to expand header to sizeof(struct llc_xid_info)
+		 * since llc_pdu_init_as_xid_cmd() sets 4,5,6 bytes of LLC header
+		 * as XID PDU. In llc_ui_sendmsg() we reserved header size and then
+		 * filled all other space with user data. If we won't reserve this
+		 * bytes, llc_pdu_init_as_xid_cmd() will overwrite user data
+		 */
+		rc = LLC_PDU_LEN_U_XID;
 	else if (sk->sk_type == SOCK_STREAM)
 		rc = LLC_PDU_LEN_I;
 	return rc;
@@ -268,6 +276,7 @@ static int llc_ui_autobind(struct socket *sock, struct sockaddr_llc *addr)
 {
 	struct sock *sk = sock->sk;
 	struct llc_sock *llc = llc_sk(sk);
+	struct net_device *dev = NULL;
 	struct llc_sap *sap;
 	int rc = -EINVAL;
 
@@ -279,14 +288,14 @@ static int llc_ui_autobind(struct socket *sock, struct sockaddr_llc *addr)
 		goto out;
 	rc = -ENODEV;
 	if (sk->sk_bound_dev_if) {
-		llc->dev = dev_get_by_index(&init_net, sk->sk_bound_dev_if);
-		if (llc->dev && addr->sllc_arphrd != llc->dev->type) {
-			dev_put(llc->dev);
-			llc->dev = NULL;
+		dev = dev_get_by_index(&init_net, sk->sk_bound_dev_if);
+		if (dev && addr->sllc_arphrd != dev->type) {
+			dev_put(dev);
+			dev = NULL;
 		}
 	} else
-		llc->dev = dev_getfirstbyhwtype(&init_net, addr->sllc_arphrd);
-	if (!llc->dev)
+		dev = dev_getfirstbyhwtype(&init_net, addr->sllc_arphrd);
+	if (!dev)
 		goto out;
 	rc = -EUSERS;
 	llc->laddr.lsap = llc_ui_autoport();
@@ -296,6 +305,11 @@ static int llc_ui_autobind(struct socket *sock, struct sockaddr_llc *addr)
 	sap = llc_sap_open(llc->laddr.lsap, NULL);
 	if (!sap)
 		goto out;
+
+	/* Note: We do not expect errors from this point. */
+	llc->dev = dev;
+	dev = NULL;
+
 	memcpy(llc->laddr.mac, llc->dev->dev_addr, IFHWADDRLEN);
 	memcpy(&llc->addr, addr, sizeof(llc->addr));
 	/* assign new connection to its SAP */
@@ -303,6 +317,7 @@ static int llc_ui_autobind(struct socket *sock, struct sockaddr_llc *addr)
 	sock_reset_flag(sk, SOCK_ZAPPED);
 	rc = 0;
 out:
+	dev_put(dev);
 	return rc;
 }
 
@@ -325,6 +340,7 @@ static int llc_ui_bind(struct socket *sock, struct sockaddr *uaddr, int addrlen)
 	struct sockaddr_llc *addr = (struct sockaddr_llc *)uaddr;
 	struct sock *sk = sock->sk;
 	struct llc_sock *llc = llc_sk(sk);
+	struct net_device *dev = NULL;
 	struct llc_sap *sap;
 	int rc = -EINVAL;
 
@@ -341,25 +357,26 @@ static int llc_ui_bind(struct socket *sock, struct sockaddr *uaddr, int addrlen)
 	rc = -ENODEV;
 	rcu_read_lock();
 	if (sk->sk_bound_dev_if) {
-		llc->dev = dev_get_by_index_rcu(&init_net, sk->sk_bound_dev_if);
-		if (llc->dev) {
+		dev = dev_get_by_index_rcu(&init_net, sk->sk_bound_dev_if);
+		if (dev) {
 			if (is_zero_ether_addr(addr->sllc_mac))
-				memcpy(addr->sllc_mac, llc->dev->dev_addr,
+				memcpy(addr->sllc_mac, dev->dev_addr,
 				       IFHWADDRLEN);
-			if (addr->sllc_arphrd != llc->dev->type ||
+			if (addr->sllc_arphrd != dev->type ||
 			    !ether_addr_equal(addr->sllc_mac,
-					      llc->dev->dev_addr)) {
+					      dev->dev_addr)) {
 				rc = -EINVAL;
-				llc->dev = NULL;
+				dev = NULL;
 			}
 		}
-	} else
-		llc->dev = dev_getbyhwaddr_rcu(&init_net, addr->sllc_arphrd,
+	} else {
+		dev = dev_getbyhwaddr_rcu(&init_net, addr->sllc_arphrd,
 					   addr->sllc_mac);
-	if (llc->dev)
-		dev_hold(llc->dev);
+	}
+	if (dev)
+		dev_hold(dev);
 	rcu_read_unlock();
-	if (!llc->dev)
+	if (!dev)
 		goto out;
 	if (!addr->sllc_sap) {
 		rc = -EUSERS;
@@ -392,6 +409,11 @@ static int llc_ui_bind(struct socket *sock, struct sockaddr *uaddr, int addrlen)
 			goto out_put;
 		}
 	}
+
+	/* Note: We do not expect errors from this point. */
+	llc->dev = dev;
+	dev = NULL;
+
 	llc->laddr.lsap = addr->sllc_sap;
 	memcpy(llc->laddr.mac, addr->sllc_mac, IFHWADDRLEN);
 	memcpy(&llc->addr, addr, sizeof(llc->addr));
@@ -402,6 +424,7 @@ static int llc_ui_bind(struct socket *sock, struct sockaddr *uaddr, int addrlen)
 out_put:
 	llc_sap_put(sap);
 out:
+	dev_put(dev);
 	release_sock(sk);
 	return rc;
 }