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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 00:43:05 -0800	[thread overview]
Message-ID: <20190214084305.GC29560@sol.localdomain> (raw)
In-Reply-To: <CAKv+Gu_EuPpXvt0xLrA7H1fwWifCifpgaMDiZ_jvA0VT_7H21w@mail.gmail.com>

On Thu, Feb 14, 2019 at 09:33:51AM +0100, Ard Biesheuvel wrote:
> On Thu, 14 Feb 2019 at 09:28, Eric Biggers <ebiggers@kernel.org> wrote:
> >
> > 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.
> >
> 
> Fair enough.
> 
> Do you have a branch with this stuff that I can drop into kernelci
> again? Preferably one that already has the tests enabled by default,
> and panics on failure.

I pushed it out to https://git.kernel.org/pub/scm/linux/kernel/git/ebiggers/linux.git
branch "iv-out-testing", and added a hack to enable self-tests by default and
panic on test failure.

- Eric

  reply	other threads:[~2019-02-14  8:43 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
2019-02-14  8:33       ` Ard Biesheuvel
2019-02-14  8:43         ` Eric Biggers [this message]
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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