3.16.7-ckt26 -stable review patch. If anyone has any objections, please let me know. ---8<------------------------------------------------------------ From: Rainer Weikusat <rweikusat@xxxxxxxxxxxxxxxxxxxxxxx> commit 1b92ee3d03af6643df395300ba7748f19ecdb0c5 upstream. The present unix_stream_read_generic contains various code sequences of the form err = -EDISASTER; if (<test>) goto out; This has the unfortunate side effect of possibly causing the error code to bleed through to the final out: return copied ? : err; and then to be wrongly returned if no data was copied because the caller didn't supply a data buffer, as demonstrated by the program available at http://pad.lv/1540731 Change it such that err is only set if an error condition was detected. Fixes: 3822b5c2fc62 ("af_unix: Revert 'lock_interruptible' in stream receive code") Reported-by: Joseph Salisbury <joseph.salisbury@xxxxxxxxxxxxx> Signed-off-by: Rainer Weikusat <rweikusat@xxxxxxxxxxxxxxxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> [ luis: backported to 3.16: - modify unix_stream_recvmsg() instead of unix_stream_read_generic() - adjusted context ] Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx> --- net/unix/af_unix.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c index bfc5f03889a9..5a5721a7f9e0 100644 --- a/net/unix/af_unix.c +++ b/net/unix/af_unix.c @@ -2092,13 +2092,15 @@ static int unix_stream_recvmsg(struct kiocb *iocb, struct socket *sock, long timeo; int skip; - err = -EINVAL; - if (sk->sk_state != TCP_ESTABLISHED) + if (unlikely(sk->sk_state != TCP_ESTABLISHED)) { + err = -EINVAL; goto out; + } - err = -EOPNOTSUPP; - if (flags&MSG_OOB) + if (unlikely(flags & MSG_OOB)) { + err = -EOPNOTSUPP; goto out; + } target = sock_rcvlowat(sk, flags&MSG_WAITALL, size); timeo = sock_rcvtimeo(sk, noblock); @@ -2146,9 +2148,11 @@ again: goto unlock; unix_state_unlock(sk); - err = -EAGAIN; - if (!timeo) + if (!timeo) { + err = -EAGAIN; break; + } + mutex_unlock(&u->readlock); timeo = unix_stream_data_wait(sk, timeo, last); -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html