[3.13.y-ckt stable] Patch "af_unix: Don't set err in unix_stream_read_generic unless there was an error" has been added to the 3.13.y-ckt tree
Kamal Mostafa
kamal at canonical.com
Wed Mar 9 23:13:05 UTC 2016
This is a note to let you know that I have just added a patch titled
af_unix: Don't set err in unix_stream_read_generic unless there was an error
to the linux-3.13.y-queue branch of the 3.13.y-ckt extended stable tree
which can be found at:
http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.13.y-queue
This patch is scheduled to be released in version 3.13.11-ckt36.
If you, or anyone else, feels it should not be added to this tree, please
reply to this email.
For more information about the 3.13.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable
Thanks.
-Kamal
---8<------------------------------------------------------------
>From 7861b964ad07c91eebf52c61d263aacf1dd15371 Mon Sep 17 00:00:00 2001
From: Rainer Weikusat <rweikusat at mobileactivedefense.com>
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
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 at canonical.com>
Signed-off-by: Rainer Weikusat <rweikusat at mobileactivedefense.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
[ luis: backported to 3.16:
- modify unix_stream_recvmsg() instead of unix_stream_read_generic()
- adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
Signed-off-by: Kamal Mostafa <kamal at 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 3974413..17a824b 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -2089,13 +2089,15 @@ 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);
@@ -2143,9 +2145,11 @@ 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
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