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authorRainer Weikusat <rweikusat@mobileactivedefense.com>2016-02-08 18:47:19 +0000
committerDavid S. Miller <davem@davemloft.net>2016-02-16 12:48:04 -0500
commit1b92ee3d03af6643df395300ba7748f19ecdb0c5 (patch)
tree174da5394bc86b1f6a66a69ce9da19a688dae40a /net
parentdb92ea5d4df00271b57d79c2d03dae5a5d60fcc1 (diff)
downloadlinux-1b92ee3d03af6643df395300ba7748f19ecdb0c5.tar.bz2
af_unix: Don't set err in unix_stream_read_generic unless there was an error
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@canonical.com> Signed-off-by: Rainer Weikusat <rweikusat@mobileactivedefense.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/unix/af_unix.c16
1 files changed, 10 insertions, 6 deletions
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 29be035f9c65..df923caa8389 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -2277,13 +2277,15 @@ static int unix_stream_read_generic(struct unix_stream_read_state *state)
size_t size = state->size;
unsigned int last_len;
- 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);
@@ -2329,9 +2331,11 @@ 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,