Bluetooth: Fix potential NULL dereference in RFCOMM bind callback

addr can be NULL and it should not be dereferenced before NULL checking.

Signed-off-by: Jaganath Kanakkassery <jaganath.k@samsung.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
[sw0312.kim: cherry-pick from mainline to fix CVE-2015-8956]
Signed-off-by: Seung-Woo Kim <sw0312.kim@samsung.com>
Change-Id: Ie2d6b563f5c5835486fd5dca119b676d58a2a37c

diff --git a/net/bluetooth/rfcomm/sock.c b/net/bluetooth/rfcomm/sock.c
index 9355027..f47d00f 100644 (file)
--- a/net/bluetooth/rfcomm/sock.c
+++ b/net/bluetooth/rfcomm/sock.c
@@ -344,16 +344,19 @@ static int rfcomm_sock_create(struct net *net, struct socket *sock,
 
 static int rfcomm_sock_bind(struct socket *sock, struct sockaddr *addr, int addr_len)
 {
-       struct sockaddr_rc *sa = (struct sockaddr_rc *) addr;
+       struct sockaddr_rc sa;
        struct sock *sk = sock->sk;
-       int chan = sa->rc_channel;
-       int err = 0;
-
-       BT_DBG("sk %p %pMR", sk, &sa->rc_bdaddr);
+       int len, err = 0;
 
        if (!addr || addr->sa_family != AF_BLUETOOTH)
                return -EINVAL;
 
+       memset(&sa, 0, sizeof(sa));
+       len = min_t(unsigned int, sizeof(sa), addr_len);
+       memcpy(&sa, addr, len);
+
+       BT_DBG("sk %p %pMR", sk, &sa.rc_bdaddr);
+
        lock_sock(sk);
 
        if (sk->sk_state != BT_OPEN) {
@@ -368,12 +371,13 @@ static int rfcomm_sock_bind(struct socket *sock, struct sockaddr *addr, int addr
 
        write_lock(&rfcomm_sk_list.lock);
 
-       if (chan && __rfcomm_get_listen_sock_by_addr(chan, &sa->rc_bdaddr)) {
+       if (sa.rc_channel &&
+           __rfcomm_get_listen_sock_by_addr(sa.rc_channel, &sa.rc_bdaddr)) {
                err = -EADDRINUSE;
        } else {
                /* Save source address */
-               bacpy(&rfcomm_pi(sk)->src, &sa->rc_bdaddr);
-               rfcomm_pi(sk)->channel = chan;
+               bacpy(&rfcomm_pi(sk)->src, &sa.rc_bdaddr);
+               rfcomm_pi(sk)->channel = sa.rc_channel;
                sk->sk_state = BT_BOUND;
        }