4.2.8-ckt5 -stable review patch. If anyone has any objections, please let me
know.
---8<------------------------------------------------------------
From: Rainer Weikusat <rweiku...@mobileactivedefense.com>
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.salisb...@canonical.com>
Signed-off-by: Rainer Weikusat <rweiku...@mobileactivedefense.com>
Signed-off-by: David S. Miller <da...@davemloft.net>
Signed-off-by: Kamal Mostafa <ka...@canonical.com>
---
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 b5f9049..18a0116 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -2274,13 +2274,15 @@ 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);
@@ -2326,9 +2328,11 @@ 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,
--
2.7.0
