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From: Herbert Xu <herbert@gondor.apana.org.au>
To: Fabio Estevam <festevam@gmail.com>
Cc: marex@denx.de, s.trumtrar@pengutronix.de,
	thomas.lendacky@amd.com, linux@arm.linux.org.uk,
	linux-crypto@vger.kernel.org,
	Fabio Estevam <fabio.estevam@nxp.com>
Subject: Re: [PATCH v2 1/3] crypto: sahara - avoid needlessly saving and restoring sahara_ctx
Date: Mon, 25 Jan 2016 22:07:28 +0800	[thread overview]
Message-ID: <20160125140728.GA8414@gondor.apana.org.au> (raw)
In-Reply-To: <1452707524-7695-1-git-send-email-festevam@gmail.com>

On Wed, Jan 13, 2016 at 03:52:02PM -0200, Fabio Estevam wrote:
> From: Fabio Estevam <fabio.estevam@nxp.com>
> 
> Based on commit 434b421241f2d0 ("crypto: caam - avoid needlessly saving and
> restoring caam_hash_ctx") from Russell King.
> 
> When exporting and importing the hash state, we will only export and
> import into hashes which share the same struct crypto_ahash pointer.
> (See hash_accept->af_alg_accept->hash_accept_parent.)
>     
> This means that saving the sahara_ctx structure on export, and
> restoring it on import is a waste of resources.  So, remove this code.
> 
> Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>

Very good.  Not only is it a waste, it's a gaping security hole
because modifying the tfm from import will corrupt it.

But this is not enough, you're still copying things like the mutex
which should not be copied but instead should be reinitialised in
import.

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

  parent reply	other threads:[~2016-01-25 14:07 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-01-13 17:52 [PATCH v2 1/3] crypto: sahara - avoid needlessly saving and restoring sahara_ctx Fabio Estevam
2016-01-13 17:52 ` [PATCH v2 2/3] crypto: sahara - fill the statesize field Fabio Estevam
2016-01-13 17:52 ` [PATCH v2 3/3] crypto: mxs-dcp - provide statesize and import/export() Fabio Estevam
2016-01-25 14:10   ` Herbert Xu
2016-01-25 14:07 ` Herbert Xu [this message]
2016-02-02 13:41   ` [PATCH v2 1/3] crypto: sahara - avoid needlessly saving and restoring sahara_ctx Fabio Estevam
2016-02-02 14:43     ` Herbert Xu
2016-02-02 17:18       ` Fabio Estevam
2016-02-03 11:22         ` Herbert Xu

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