linux-kernel - Re: [PATCH v2] crypto: AF_ALG - wait for data at beginning of recvmsg

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Date:   Mon, 11 Dec 2017 22:45:24 +1100
From:   Herbert Xu <herbert@...dor.apana.org.au>
To:     Stephan Müller <smueller@...onox.de>
Cc:     Eric Biggers <ebiggers3@...il.com>,
        syzbot 
        <bot+3401d9494b9380f7244bcc7fec49680878fccba6@...kaller.appspotmail.com>,
        davem@...emloft.net, linux-crypto@...r.kernel.org,
        linux-kernel@...r.kernel.org, syzkaller-bugs@...glegroups.com
Subject: Re: [PATCH v2] crypto: AF_ALG - wait for data at beginning of recvmsg

On Wed, Nov 29, 2017 at 12:02:23PM +0100, Stephan Müller wrote:
> The wait for data is a non-atomic operation that can sleep and therefore
> potentially release the socket lock. The release of the socket lock
> allows another thread to modify the context data structure. The waiting
> operation for new data therefore must be called at the beginning of
> recvmsg. This prevents a race condition where checks of the members of
> the context data structure are performed by recvmsg while there is a
> potential for modification of these values.
> 
> Fixes: e870456d8e7c ("crypto: algif_skcipher - overhaul memory management")
> Fixes: d887c52d6ae4 ("crypto: algif_aead - overhaul memory management")
> Reported-by: syzbot <syzkaller@...glegroups.com>
> Cc: <stable@...r.kernel.org> # v4.14+
> Signed-off-by: Stephan Mueller <smueller@...onox.de>

Patch applied.  Thanks.
-- 
Email: Herbert Xu <herbert@...dor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt