From: Romain Izard <romain.izard.pro@gmail.com>
To: Tudor Ambarus <tudor.ambarus@microchip.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>,
"David S . Miller" <davem@davemloft.net>,
Nicolas Ferre <nicolas.ferre@microchip.com>,
linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
linux-crypto@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 2/2] crypto: atmel-aes - Reset the controller before each use
Date: Mon, 6 Nov 2017 16:57:12 +0100 [thread overview]
Message-ID: <CAGkQfmNFZcfeTVPOhQEwqXjaUPVu1se+j-x_kbrB29ag_4OU9A@mail.gmail.com> (raw)
In-Reply-To: <ff2356ef-2c11-18e5-6da2-654b1d77280c@microchip.com>
2017-11-06 16:45 GMT+01:00 Tudor Ambarus <tudor.ambarus@microchip.com>:
> Hi, Romain,
>
> On 10/31/2017 05:25 PM, Romain Izard wrote:
>>
>> When using the rfc4543(gcm(aes))) mode, the registers of the hardware
>> engine are not empty after use. If the engine is not reset before its
>> next use, the following results will be invalid.
>>
>> Always reset the hardware engine.
>
>
> Thanks for the fix! I could reproduce the issue only when running
> rfc4543(gcm(aes))) and then, immediately after, ecb(aes).
>
> Have you encountered this bug with other combination of algorithms?
>
> I'm trying to isolate the bug so that we can have a more fine-grained
> fix.
I just ran the tcrypt tests because they were failing on the
cts(cbc(aes)) transform and I observed this issue when the ecb
test failed only on the second run.
For me, the issue looks like the rfc4543 mode does not read
all the registers from the AES engine, and the following operation
fails because the registers are reused directly in the ECB mode.
As the ECB mode is a rare case where we do not use an IV, this
may be the reason why other modes do not display the issue.
--
Romain Izard
next prev parent reply other threads:[~2017-11-06 15:57 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-31 15:25 [PATCH 0/2] Fixes for the Atmel AES crypto module Romain Izard
2017-10-31 15:25 ` [PATCH 1/2] crypto: atmel-aes - properly set IV after {en,de}crypt Romain Izard
2017-10-31 15:25 ` [PATCH 2/2] crypto: atmel-aes - Reset the controller before each use Romain Izard
2017-11-06 15:45 ` Tudor Ambarus
2017-11-06 15:57 ` Romain Izard [this message]
2017-11-03 14:28 ` [PATCH 0/2] Fixes for the Atmel AES crypto module Herbert Xu
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=CAGkQfmNFZcfeTVPOhQEwqXjaUPVu1se+j-x_kbrB29ag_4OU9A@mail.gmail.com \
--to=romain.izard.pro@gmail.com \
--cc=davem@davemloft.net \
--cc=herbert@gondor.apana.org.au \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-crypto@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=nicolas.ferre@microchip.com \
--cc=tudor.ambarus@microchip.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).