From: Eric Biggers <ebiggers@kernel.org>
To: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: "open list:HARDWARE RANDOM NUMBER GENERATOR CORE"
<linux-crypto@vger.kernel.org>,
Herbert Xu <herbert@gondor.apana.org.au>
Subject: Re: [PATCH 5/6] crypto: arm64/aes-blk - update IV after partial final CTR block
Date: Thu, 14 Feb 2019 00:28:29 -0800 [thread overview]
Message-ID: <20190214082827.GB29560@sol.localdomain> (raw)
In-Reply-To: <CAKv+Gu9J_PKP0MfScA+RTV3m7FPyVwD713fBeTjn9cA8sWSVAw@mail.gmail.com>
On Thu, Feb 14, 2019 at 09:14:13AM +0100, Ard Biesheuvel wrote:
> On Thu, 14 Feb 2019 at 09:04, Eric Biggers <ebiggers@kernel.org> wrote:
> >
> > From: Eric Biggers <ebiggers@google.com>
> >
> > Make the arm64 ctr-aes-neon and ctr-aes-ce algorithms update the IV
> > buffer to contain the next counter after processing a partial final
> > block, rather than leave it as the last counter. This makes these
> > algorithms pass the updated AES-CTR tests.
> >
> > Signed-off-by: Eric Biggers <ebiggers@google.com>
>
> I take it this means we return an output IV even if the algorithm
> could never proceed in a meaningful way, given that we throw away some
> keystream bits that would be needed in that case.
>
> That means this change is strictly there to make the test framework
> happy, even for cases that can never appear in reality.
>
> Wouldn't it be better not to set out_iv for input buffers whose size
> is not a multiple of the block size?
>
See the explanation in patch 4 for why the tests test for this. It's not a
super strong argument but this seems like the best thing to do.
- Eric
next prev parent reply other threads:[~2019-02-14 8:28 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-14 8:03 [PATCH 0/6] crypto: test that CBC and CTR update the IV Eric Biggers
2019-02-14 8:03 ` [PATCH 1/6] crypto: testmgr - remove extra bytes from 3DES-CTR IVs Eric Biggers
2019-02-14 8:03 ` [PATCH 2/6] crypto: testmgr - support checking skcipher output IV Eric Biggers
2019-02-14 8:03 ` [PATCH 3/6] crypto: testmgr - add iv_out to all CBC test vectors Eric Biggers
2019-02-14 8:03 ` [PATCH 4/6] crypto: testmgr - add iv_out to all CTR " Eric Biggers
2019-02-14 8:03 ` [PATCH 5/6] crypto: arm64/aes-blk - update IV after partial final CTR block Eric Biggers
2019-02-14 8:14 ` Ard Biesheuvel
2019-02-14 8:28 ` Eric Biggers [this message]
2019-02-14 8:33 ` Ard Biesheuvel
2019-02-14 8:43 ` Eric Biggers
2019-02-14 8:03 ` [PATCH 6/6] crypto: arm/aes-ce " Eric Biggers
2019-02-22 12:00 ` [PATCH 0/6] crypto: test that CBC and CTR update the IV Herbert Xu
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