Re: [PATCH 3/4] DRBG: fix memory corruption for AES192

From: Herbert Xu
Date: Thu Jul 03 2014 - 23:08:34 EST


On Tue, Jul 01, 2014 at 05:08:48PM +0200, Stephan Mueller wrote:
> For the CTR DRBG, the drbg_state->scratchpad temp buffer (i.e. the
> memory location immediately before the drbg_state->tfm variable
> is the buffer that the BCC function operates on. BCC operates
> blockwise. Making the temp buffer drbg_statelen(drbg) in size is
> sufficient when the DRBG state length is a multiple of the block
> size. For AES192 this is not the case and the length for temp is
> insufficient (yes, that also means for such ciphers, the final
> output of all BCC rounds are truncated before used to update the
> state of the DRBG!!).
>
> The patch enlarges the temp buffer from drbg_statelen to
> drbg_statelen + drbg_blocklen to have sufficient space.
>
> Reported-by: Fengguang Wu <fengguang.wu@xxxxxxxxx>
> Signed-off-by: Stephan Mueller <smueller@xxxxxxxxxx>

I have applied just this patch out of your series. You patches
depend on the previous four patches which I have not yet applied
since there are still outstanding issues with two of them.

Cheers,
--
Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
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