From: Herbert Xu <herbert@gondor.apana.org.au>
To: Eric Biggers <ebiggers3@gmail.com>
Cc: Stephan Mueller <smueller@chronox.de>,
syzbot
<bot+6fbc13c3b1ed2105e7a2e516be43d6a0624a59c0@syzkaller.appspotmail.com>,
davem@davemloft.net, linux-crypto@vger.kernel.org,
linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com
Subject: Re: KASAN: use-after-free Read in aead_recvmsg
Date: Wed, 29 Nov 2017 16:23:05 +1100 [thread overview]
Message-ID: <20171129052305.GA19831@gondor.apana.org.au> (raw)
In-Reply-To: <20171128072944.GA23565@zzz.localdomain>
On Mon, Nov 27, 2017 at 11:29:44PM -0800, Eric Biggers wrote:
>
> >From 453b54793e843c0d5b8fd2d5e33fcc5427ec038e Mon Sep 17 00:00:00 2001
> From: Eric Biggers <ebiggers@google.com>
> Date: Mon, 27 Nov 2017 23:23:05 -0800
> Subject: [PATCH] crypto: algif_aead - fix reference counting of null skcipher
>
> In the AEAD interface for AF_ALG, the reference to the "null skcipher"
> held by each tfm was being dropped in the wrong place -- when each
> af_alg_ctx was freed instead of when the aead_tfm was freed. As
> discovered by syzkaller, a specially crafted program could use this to
> cause the null skcipher to be freed while it is still in use.
>
> Fix it by dropping the reference in the right place.
>
> Fixes: 72548b093ee3 ("crypto: algif_aead - copy AAD from src to dst")
> Reported-by: syzbot <syzkaller@googlegroups.com>
> Cc: <stable@vger.kernel.org> # v4.14+
> Signed-off-by: Eric Biggers <ebiggers@google.com>
Patch applied. Thanks.
--
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
next prev parent reply other threads:[~2017-11-29 5:23 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-27 18:56 KASAN: use-after-free Read in aead_recvmsg syzbot
2017-11-27 22:02 ` Stephan Müller
2017-11-27 22:43 ` Eric Biggers
2017-11-28 6:30 ` Stephan Mueller
2017-11-28 7:29 ` Eric Biggers
2017-11-28 7:43 ` Stephan Mueller
2017-11-29 5:23 ` Herbert Xu [this message]
2017-12-01 19:11 ` Eric Biggers
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