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

From: Stephan Mueller
Date: Thu Jul 03 2014 - 23:37:51 EST


Am Freitag, 4. Juli 2014, 11:12:35 schrieb Herbert Xu:

Hi Herbert,

> 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>
>
> BTW your patches were all corrupted by your mailer so I had to
> fix them by hand. Please check the cryptodev tree to ensure
> that my fixes are correct.

The patch fixing the memory corruption is completely and correctly applied.

Apologies for sending broken patches. If I shall resend them corrected, please
let me know.
>
> In future please test your patches by applying your own patches
> returned via the list.

I will do that.

--
Ciao
Stephan
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