[Bluetooth] Fix uninitialized return value for RFCOMM sendmsg()

When calling send() with a zero length parameter on a RFCOMM socket
it returns a positive value. In this rare case the variable err is
used uninitialized and unfortunately its value is returned.

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

diff --git a/net/bluetooth/rfcomm/sock.c b/net/bluetooth/rfcomm/sock.c
index 544d65b..cb7e855 100644 (file)
--- a/net/bluetooth/rfcomm/sock.c
+++ b/net/bluetooth/rfcomm/sock.c
@@ -557,7 +557,6 @@ static int rfcomm_sock_sendmsg(struct kiocb *iocb, struct socket *sock,
        struct sock *sk = sock->sk;
        struct rfcomm_dlc *d = rfcomm_pi(sk)->dlc;
        struct sk_buff *skb;
-       int err;
        int sent = 0;
 
        if (msg->msg_flags & MSG_OOB)
@@ -572,6 +571,7 @@ static int rfcomm_sock_sendmsg(struct kiocb *iocb, struct socket *sock,
 
        while (len) {
                size_t size = min_t(size_t, len, d->mtu);
+               int err;
                
                skb = sock_alloc_send_skb(sk, size + RFCOMM_SKB_RESERVE,
                                msg->msg_flags & MSG_DONTWAIT, &err);
@@ -582,13 +582,16 @@ static int rfcomm_sock_sendmsg(struct kiocb *iocb, struct socket *sock,
                err = memcpy_fromiovec(skb_put(skb, size), msg->msg_iov, size);
                if (err) {
                        kfree_skb(skb);
-                       sent = err;
+                       if (sent == 0)
+                               sent = err;
                        break;
                }
 
                err = rfcomm_dlc_send(d, skb);
                if (err < 0) {
                        kfree_skb(skb);
+                       if (sent == 0)
+                               sent = err;
                        break;
                }
 
@@ -598,7 +601,7 @@ static int rfcomm_sock_sendmsg(struct kiocb *iocb, struct socket *sock,
 
        release_sock(sk);
 
-       return sent ? sent : err;
+       return sent;
 }
 
 static long rfcomm_sock_data_wait(struct sock *sk, long timeo)