Re: Oops in authenc: 2.6.26.3

[Matt LaPlante]

On Thu, 21 Aug 2008 18:36:15 +1000
Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> wrote:

> On Thu, Aug 21, 2008 at 07:02:25AM +0000, Sascha Biberhofer wrote:
> > I have the same problem on my system, starting with the release of
> > 2.6.26. Shortly afterwards I've had the same problem with the 2.6.25
> > series starting with 2.6.25.12. I've looked up the changes between
> > 2.6.25.11 and .12 and found commit
> > c2bd04d8040a91fe2ee2e9fee1a6562ca9792249 (it's commit
> > 872ac8743cb400192a9fce4ba2d3ffd7bb309685 in the 2.6.26 series).
> > Reverting the commit seems to solve the problem here, I've been running
> > a 2.6.25.12 kernel without this commit for some weeks now.
> > In case it's important: I'm using an IPSec ESP transport with AES-256
> > and sha-256 auth. 
> 
> Sorry, I was skimping on memory and ended up calling a clobbered
> function pointer.
> 
> This patch should fix it.
> 
> crypto: authenc - Avoid using clobbered request pointer
> 
> Authenc works in two stages for encryption, it first encrypts and
> then computes an ICV.  The context memory of the request is used
> by both operations.  The problem is that when an asynchronous
> encryption completes, we will compute the ICV and then reread the
> context memory of the encryption to get the original request.
> 
> It just happens that we have a buffer of 16 bytes in front of the
> request pointer, so ICVs of 16 bytes (such as SHA1) do not trigger
> the bug.  However, any attempt to uses a larger ICV instantly kills
> the machine when the first asynchronous encryption is completed.
> 
> This patch fixes this by saving the request pointer before we start
> the ICV computation.
> 
> Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>

Acked-by: Matt LaPlante <kernel1@xxxxxxxxxxxxxxxx>

Thanks for the quick fix!

-- 
Matt LaPlante

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