Re: [v2.6.34-stable 004/213] crypto: ghash - Avoid null pointerdereference if no key is set

From: Nick Bowler
Date: Wed Feb 05 2014 - 15:42:49 EST

On 2014-02-05 14:59 -0500, Paul Gortmaker wrote:
> From: Nick Bowler <nbowler@xxxxxxxxxxxxxxxx>
> -------------------
> This is a commit scheduled for the next v2.6.34 longterm release.
> If you see a problem with using this for longterm, please comment.
> -------------------
> commit 7ed47b7d142ec99ad6880bbbec51e9f12b3af74c upstream.
> The ghash_update function passes a pointer to gf128mul_4k_lle which will
> be NULL if ghash_setkey is not called or if the most recent call to
> ghash_setkey failed to allocate memory. This causes an oops. Fix this
> up by returning an error code in the null case.
> This is trivially triggered from unprivileged userspace through the
> AF_ALG interface by simply writing to the socket without setting a key.

After all this time, I see this patch still manages to find its way,
occasionally, into the patch queue for older -stable. :)

It should be harmless to apply, but this patch doesn't actually fix
any real problem on kernels previous to 2.6.38 because the AF_ALG
userspace interface does not exist in these kernels.

Nick Bowler, Elliptic Technologies (
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