Linux-Crypto Archive on lore.kernel.org
 help / color / Atom feed
From: Milan Broz <gmazyland@gmail.com>
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>,
	Eric Biggers <ebiggers@google.com>,
	device-mapper development <dm-devel@redhat.com>,
	linux-fscrypt@vger.kernel.org,
	Gilad Ben-Yossef <gilad@benyossef.com>
Subject: Re: [PATCH v9 3/7] md: dm-crypt: switch to ESSIV crypto API template
Date: Mon, 12 Aug 2019 09:44:47 +0200
Message-ID: <82a87cae-8eb7-828c-35c3-fb39a9abe692@gmail.com> (raw)
In-Reply-To: <CAKv+Gu-ZPPR5xQSR6T4o+8yJvsHY2a3xXZ5zsM_aGS3frVChgQ@mail.gmail.com>

On 12/08/2019 08:54, Ard Biesheuvel wrote:
> On Mon, 12 Aug 2019 at 09:33, Milan Broz <gmazyland@gmail.com> wrote:
>> Try for example
>> # cryptsetup luksFormat /dev/sdc -c aes-cbc-essiv:sha256 --integrity hmac-sha256 -q -i1
>>
>> It should produce Crypto API string
>>   authenc(hmac(sha256),essiv(cbc(aes),sha256))
>> while it produces
>>   essiv(authenc(hmac(sha256),cbc(aes)),sha256)
>> (and fails).
>>
> 
> No. I don't know why it fails, but the latter is actually the correct
> string. The essiv template is instantiated either as a skcipher or as
> an aead, and it encapsulates the entire transformation. (This is
> necessary considering that the IV is passed via the AAD and so the
> ESSIV handling needs to touch that as well)

Hm. Constructing these strings seems to be more confusing than dmcrypt mode combinations :-)

But you are right, I actually tried the former string (authenc(hmac(sha256),essiv(cbc(aes),sha256)))
and it worked, but I guess the authenticated IV (AAD) was actually the input to IV (plain sector number)
not the output of ESSIV? Do I understand it correctly now?

Milan

  reply index

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-10  9:40 [PATCH v9 0/7] crypto: switch to crypto API for ESSIV generation Ard Biesheuvel
2019-08-10  9:40 ` [PATCH v9 1/7] crypto: essiv - create wrapper template " Ard Biesheuvel
2019-08-10  9:40 ` [PATCH v9 2/7] fs: crypto: invoke crypto API for ESSIV handling Ard Biesheuvel
2019-08-10  9:40 ` [PATCH v9 3/7] md: dm-crypt: switch to ESSIV crypto API template Ard Biesheuvel
2019-08-12  6:33   ` Milan Broz
2019-08-12  6:54     ` Ard Biesheuvel
2019-08-12  7:44       ` Milan Broz [this message]
2019-08-12  7:50         ` Ard Biesheuvel
2019-08-12 13:51           ` Milan Broz
2019-08-12 14:19             ` Ard Biesheuvel
2019-08-10  9:40 ` [PATCH v9 4/7] crypto: essiv - add tests for essiv in cbc(aes)+sha256 mode Ard Biesheuvel
2019-08-10  9:40 ` [PATCH v9 5/7] crypto: arm64/aes-cts-cbc - factor out CBC en/decryption of a walk Ard Biesheuvel
2019-08-10  9:40 ` [PATCH v9 6/7] crypto: arm64/aes - implement accelerated ESSIV/CBC mode Ard Biesheuvel
2019-08-10  9:40 ` [PATCH v9 7/7] md: dm-crypt: omit parsing of the encapsulated cipher Ard Biesheuvel

Reply instructions:

You may reply publically 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=82a87cae-8eb7-828c-35c3-fb39a9abe692@gmail.com \
    --to=gmazyland@gmail.com \
    --cc=ard.biesheuvel@linaro.org \
    --cc=dm-devel@redhat.com \
    --cc=ebiggers@google.com \
    --cc=gilad@benyossef.com \
    --cc=herbert@gondor.apana.org.au \
    --cc=linux-crypto@vger.kernel.org \
    --cc=linux-fscrypt@vger.kernel.org \
    /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

Linux-Crypto Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-crypto/0 linux-crypto/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-crypto linux-crypto/ https://lore.kernel.org/linux-crypto \
		linux-crypto@vger.kernel.org
	public-inbox-index linux-crypto

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-crypto


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git