This is a note to let you know that I've just added the patch titled
af_unix: Don't set err in unix_stream_read_generic unless there was an error
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
af_unix-don-t-set-err-in-unix_stream_read_generic-unless-there-was-an-error.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Mon Feb 29 14:33:50 PST 2016
From: Rainer Weikusat <rweikusat@xxxxxxxxxxxxxxxxxxxxxxx>
Date: Mon, 8 Feb 2016 18:47:19 +0000
Subject: af_unix: Don't set err in unix_stream_read_generic unless there was an error
From: Rainer Weikusat <rweikusat@xxxxxxxxxxxxxxxxxxxxxxx>
[ Upstream commit 1b92ee3d03af6643df395300ba7748f19ecdb0c5 ]
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/unix/af_unix.c | 16 ++++++++++------
1 file changed, 10 insertions(+), 6 deletions(-)
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -2270,13 +2270,15 @@ static int unix_stream_read_generic(stru
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);
@@ -2322,9 +2324,11 @@ 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,
Patches currently in stable-queue which might be from rweikusat@xxxxxxxxxxxxxxxxxxxxxxx are
queue-4.4/af_unix-don-t-set-err-in-unix_stream_read_generic-unless-there-was-an-error.patch
queue-4.4/af_unix-fix-struct-pid-memory-leak.patch
queue-4.4/af_unix-guard-against-other-sk-in-unix_dgram_sendmsg.patch
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