[dm-devel] [PATCH v3 0/6] crypto: switch to crypto API for ESSIV generation

[Milan Broz]

On 20/06/2019 14:09, Milan Broz wrote:
> On 20/06/2019 13:54, Ard Biesheuvel wrote:
>> On Thu, 20 Jun 2019 at 13:22, Milan Broz <gmazyland at gmail.com> wrote:
>>>
>>> On 19/06/2019 18:29, Ard Biesheuvel wrote:
>>>> This series creates an ESSIV template that produces a skcipher or AEAD
>>>> transform based on a tuple of the form '<skcipher>,<cipher>,<shash>'
>>>> (or '<aead>,<cipher>,<shash>' for the AEAD case). It exposes the
>>>> encapsulated sync or async skcipher/aead by passing through all operations,
>>>> while using the cipher/shash pair to transform the input IV into an ESSIV
>>>> output IV.
>>>>
>>>> This matches what both users of ESSIV in the kernel do, and so it is proposed
>>>> as a replacement for those, in patches #2 and #4.
>>>>
>>>> This code has been tested using the fscrypt test suggested by Eric
>>>> (generic/549), as well as the mode-test script suggested by Milan for
>>>> the dm-crypt case. I also tested the aead case in a virtual machine,
>>>> but it definitely needs some wider testing from the dm-crypt experts.
>>>>
>>>> Changes since v2:
>>>> - fixed a couple of bugs that snuck in after I'd done the bulk of my
>>>>   testing
>>>> - some cosmetic tweaks to the ESSIV template skcipher setkey function
>>>>   to align it with the aead one
>>>> - add a test case for essiv(cbc(aes),aes,sha256)
>>>> - add an accelerated implementation for arm64 that combines the IV
>>>>   derivation and the actual en/decryption in a single asm routine
>>>
>>> I run tests for the whole patchset, including some older scripts and seems
>>> it works for dm-crypt now.
>>>
>>
>> Thanks Milan, that is really helpful.
>>
>> Does this include configurations that combine authenc with essiv?
> 
> Hm, seems that we are missing these in luks2-integrity-test. I'll add them there.
> 
> I also used this older test
> https://gitlab.com/omos/dm-crypt-test-scripts/blob/master/root/test_dmintegrity.sh
> 
> (just aes-gcm-random need to be commented out, we never supported this format, it was
> written for some devel version)
> 
> But seems ESSIV is there tested only without AEAD composition...
> 
> So yes, this AEAD part need more testing.

And unfortunately it does not work - it returns EIO on sectors where it should not be data corruption.

I added few lines with length-preserving mode with ESSIV + AEAD, please could you run luks2-integrity-test
in cryptsetup upstream?

This patch adds the tests:
https://gitlab.com/cryptsetup/cryptsetup/commit/4c74ff5e5ae328cb61b44bf99f98d08ffee3366a

It is ok on mainline kernel, fails with the patchset:

# ./luks2-integrity-test 
[aes-cbc-essiv:sha256:hmac-sha256:128:512][FORMAT][ACTIVATE]sha256sum: /dev/mapper/dmi_test: Input/output error
[FAIL]
 Expecting ee501705a084cd0ab6f4a28014bcf62b8bfa3434de00b82743c50b3abf06232c got .

FAILED backtrace:
77 ./luks2-integrity-test
112 intformat ./luks2-integrity-test
127 main ./luks2-integrity-test

Milan