]> git.proxmox.com Git - mirror_ubuntu-kernels.git/commit
af_unix: Only allow recv on connected seqpacket sockets.
authorEric W. Biederman <ebiederm@xmission.com>
Sun, 24 Apr 2011 01:54:57 +0000 (01:54 +0000)
committerDavid S. Miller <davem@davemloft.net>
Mon, 2 May 2011 06:16:28 +0000 (23:16 -0700)
commita05d2ad1c1f391c7f514a1d1e09b5417968a7d07
tree911e711680c3328de540ec2530cd4bc3df3943b5
parent2b5a4ace664cfe05c17bee60c4da66263a05fccf
af_unix: Only allow recv on connected seqpacket sockets.

This fixes the following oops discovered by Dan Aloni:
> Anyway, the following is the output of the Oops that I got on the
> Ubuntu kernel on which I first detected the problem
> (2.6.37-12-generic). The Oops that followed will be more useful, I
> guess.

>[ 5594.669852] BUG: unable to handle kernel NULL pointer dereference
> at           (null)
> [ 5594.681606] IP: [<ffffffff81550b7b>] unix_dgram_recvmsg+0x1fb/0x420
> [ 5594.687576] PGD 2a05d067 PUD 2b951067 PMD 0
> [ 5594.693720] Oops: 0002 [#1] SMP
> [ 5594.699888] last sysfs file:

The bug was that unix domain sockets use a pseduo packet for
connecting and accept uses that psudo packet to get the socket.
In the buggy seqpacket case we were allowing unconnected
sockets to call recvmsg and try to receive the pseudo packet.

That is always wrong and as of commit 7361c36c5 the pseudo
packet had become enough different from a normal packet
that the kernel started oopsing.

Do for seqpacket_recv what was done for seqpacket_send in 2.5
and only allow it on connected seqpacket sockets.

Cc: stable@kernel.org
Tested-by: Dan Aloni <dan@aloni.org>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net/unix/af_unix.c