From: Gilad Ben-Yossef <gilad@benyossef.com>
To: Herbert Xu <herbert@gondor.apana.org.au>
Cc: "David S. Miller" <davem@davemloft.net>,
Hadar Gat <hadar.gat@arm.com>, Ofir Drang <ofir.drang@arm.com>,
stable@vger.kernel.org,
Linux Crypto Mailing List <linux-crypto@vger.kernel.org>,
Linux kernel mailing list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] crypto: ccree: fix iv copying for small buffers
Date: Thu, 21 Jun 2018 16:35:44 +0300 [thread overview]
Message-ID: <CAOtvUMcChKswKBCOkN7DGvK3DcotJBh0y=-Xi8232uYK26-xQA@mail.gmail.com> (raw)
In-Reply-To: <20180619142713.dzipyarpb23a7qne@gondor.apana.org.au>
On Tue, Jun 19, 2018 at 5:27 PM, Herbert Xu <herbert@gondor.apana.org.au> wrote:
> On Sun, Jun 17, 2018 at 01:06:42PM +0300, Gilad Ben-Yossef wrote:
>>
>> It was ctr(aes). I wrongly assumed that we are supposed to unconditionally
>> copy
>> the cipher-text block post operation and let the caller do with it what it
>> wants and so the
>> code now does that for all cipher operations unconditionally.
>
> For CTR it doesn't matter whether the last block is less than a
> block, you should still increment the counter.
OK. got it. Although I am not sure how does one use this to continue
encryption if the plaintext was not block aligned.
>
>> So what is a good description of what we are supposed to provide in that
>> field post operation?
>> The next IV? but as you stated, that is not necessarily useful for all
>> ciphers.
>
> When in doubt, please refer to the generic implementation. If
> that is still unclear or if it seems wrong, please post to the
> list.
Got it.
So as a sanity check if I understood correctly I need to:
- Increment counter in IV for CTS
- Copy last ciphertext block for CFB and CBC to output IV (partial
blocks not allowed)
What about OFB? unless I've missed something there is no generic
implementation... ?
Thanks again,
Gilad
--
Gilad Ben-Yossef
Chief Coffee Drinker
values of β will give rise to dom!
next prev parent reply other threads:[~2018-06-21 13:35 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-07 8:58 [PATCH] crypto: ccree: fix iv copying for small buffers Gilad Ben-Yossef
2018-06-07 9:02 ` Gilad Ben-Yossef
2018-06-08 7:30 ` Harsh Jain
2018-06-13 6:30 ` Herbert Xu
[not found] ` <CAOtvUMdtafGwXJFD0Tm1tx1q+TxRsB4nwEKxumE7=--_PMCZrQ@mail.gmail.com>
2018-06-19 14:27 ` Herbert Xu
2018-06-21 13:35 ` Gilad Ben-Yossef [this message]
2018-06-22 6:53 ` Herbert Xu
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