From: David Miller <davem@davemloft.net>
To: mschmidt@redhat.com
Cc: netdev@vger.kernel.org
Subject: Re: uninterruptible sleep in unix_dgram_recvmsg
Date: Mon, 08 Mar 2010 12:48:48 -0800 (PST) [thread overview]
Message-ID: <20100308.124848.117951181.davem@davemloft.net> (raw)
In-Reply-To: <20100304184114.62881b21@leela>
From: Michal Schmidt <mschmidt@redhat.com>
Date: Thu, 4 Mar 2010 18:41:14 +0100
> So instead of that I started to think about why u->readlock is held
> across skb_recv_datagram() anyway. I found that it was added in 2.6.10
> by your patch "[AF_UNIX]: Serialize dgram read using semaphore just
> like stream" which apparently fixed an exploitable race condition
> (CAN-2004-1068).
>
> I don't know what exactly u->readlock protects here.
> IOW, what race would this patch cause?:
Unfortunately I can't find any discussions about that change
and I can't find my own personal email archives from that far
back.
This is what irks me about handling security issues off-list
and in private.
In any event, I'm pretty sure we need to protect the dequeue
of SKBs from the datagram recv_queue with that mutex. So
I'm weary to apply your patch.
Can you find a way to fix this without moving the SKB
dequeue outside of the lock?
Thanks.
prev parent reply other threads:[~2010-03-08 20:48 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-04 17:41 uninterruptible sleep in unix_dgram_recvmsg Michal Schmidt
2010-03-08 20:48 ` David Miller [this message]
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