From: Pascal Van Leeuwen <pvanleeuwen@insidesecure.com>
To: Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Herbert Xu <herbert@gondor.apana.org.au>
Cc: Iuliana Prodan <iuliana.prodan@nxp.com>,
Eric Biggers <ebiggers@kernel.org>,
"David S. Miller" <davem@davemloft.net>,
Horia Geanta <horia.geanta@nxp.com>,
Sascha Hauer <s.hauer@pengutronix.de>,
"open list:HARDWARE RANDOM NUMBER GENERATOR CORE"
<linux-crypto@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
dl-linux-imx <linux-imx@nxp.com>
Subject: RE: [PATCH] crypto: gcm - fix cacheline sharing
Date: Thu, 30 May 2019 14:29:26 +0000 [thread overview]
Message-ID: <AM6PR09MB3523C09EFDE90A8A8ECFCA09D2180@AM6PR09MB3523.eurprd09.prod.outlook.com> (raw)
In-Reply-To: <CAKv+Gu-3zzN=cikd4PftCVo2fJi9t_0kqZHBQncjokYQV5wVnA@mail.gmail.com>
> On Thu, 30 May 2019 at 15:58, Herbert Xu <herbert@gondor.apana.org.au>
> wrote:
> >
> > On Thu, May 30, 2019 at 01:45:47PM +0000, Iuliana Prodan wrote:
> > >
> > > On the current structure of caamalg, to work, iv needs to be copied
> > > before memcpy(iv, req->iv, ivsize), from skcipher_edesc_alloc
> function.
> > > For this we need edesc, but this cannot be allocated before knowing
> how
> > > much memory we need. So, to make it work, we'll need to modify more in
> CAAM.
> >
> > All the copying does is:
> >
> > if (ivsize)
> > scatterwalk_map_and_copy(req->iv, req->src, req-
> >cryptlen -
> > ivsize, ivsize, 0);
> >
> > Why do you need to allocate the edesc before doing this?
> >
>
> Because that is where the incoming iv is currently consumed. Copying
> it out like this wipes the input IV from memory.
I had a similar problem for the Inside Secure driver: for decrypt operations,
you need to copy the output IV from your input data buffer (it's the last
input data cipher block) but you need to do that *before* you start the
hardware, as for in-place operations, it is overwritten.
At the same time, you cannot store it to req->iv yet, because that still
contains the input IV that you need for processing the first block.
The only solution I could come up with, is to park it in some temporary
buffer in the skcipher_request_ctx *before* starting the hardware and copy
it to req->iv *after* the operation completes.
Regards,
Pascal van Leeuwen
Silicon IP Architect, Multi-Protocol Engines @ Inside Secure
www.insidesecure.com
next prev parent reply other threads:[~2019-05-30 14:29 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-29 17:10 [PATCH] crypto: gcm - fix cacheline sharing Iuliana Prodan
2019-05-29 20:27 ` Eric Biggers
2019-05-29 22:16 ` Ard Biesheuvel
2019-05-30 13:29 ` Iuliana Prodan
2019-05-30 13:34 ` Herbert Xu
2019-05-30 13:45 ` Iuliana Prodan
2019-05-30 13:53 ` Ard Biesheuvel
2019-05-30 13:55 ` Ard Biesheuvel
2019-05-30 14:27 ` Herbert Xu
2019-05-30 14:28 ` Ard Biesheuvel
2019-05-30 14:31 ` Ard Biesheuvel
2019-05-30 14:34 ` Herbert Xu
2019-05-30 15:04 ` Ard Biesheuvel
2019-05-30 15:06 ` Herbert Xu
2019-05-30 15:10 ` Ard Biesheuvel
2019-05-30 15:13 ` Herbert Xu
2019-05-30 15:17 ` Ard Biesheuvel
2019-05-30 22:00 ` Iuliana Prodan
2019-05-31 5:54 ` Horia Geanta
2019-05-30 14:53 ` Pascal Van Leeuwen
2019-05-30 15:13 ` Ard Biesheuvel
2019-06-06 6:37 ` Herbert Xu
2019-06-06 6:42 ` Ard Biesheuvel
2019-06-06 6:46 ` Herbert Xu
2019-06-06 6:53 ` Ard Biesheuvel
2019-06-06 6:57 ` Herbert Xu
2019-06-06 7:10 ` Horia Geanta
2019-06-06 7:15 ` Herbert Xu
2019-06-06 8:36 ` Horia Geanta
2019-06-06 9:33 ` Herbert Xu
2019-05-30 13:58 ` Herbert Xu
2019-05-30 14:11 ` Ard Biesheuvel
2019-05-30 14:29 ` Pascal Van Leeuwen [this message]
2019-05-30 5:34 ` Herbert Xu
2019-05-30 7:46 ` Horia Geanta
2019-05-30 8:08 ` Ard Biesheuvel
2019-05-30 13:18 ` Horia Geanta
2019-05-30 13:25 ` Ard Biesheuvel
2019-05-31 6:05 ` Horia Geanta
2019-05-30 13:26 ` Herbert Xu
2019-05-31 5:22 ` Horia Geanta
2019-05-31 5:42 ` Herbert Xu
2019-05-31 6:10 ` Horia Geanta
2019-05-31 6:14 ` Herbert Xu
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