From: Daniel Axtens <dja@axtens.net>
To: Eric Biggers <ebiggers@kernel.org>
Cc: omosnacek@gmail.com, linux-crypto@vger.kernel.org,
Herbert Xu <herbert@gondor.apana.org.au>,
marcelo.cerri@canonical.com,
Stephan Mueller <smueller@chronox.de>,
leo.barbosa@canonical.com, linuxppc-dev@lists.ozlabs.org,
nayna@linux.ibm.com, pfsmorigo@gmail.com, leitao@debian.org
Subject: Re: [PATCH] crypto: vmx - fix copy-paste error in CTR mode
Date: Fri, 15 Mar 2019 16:23:02 +1100 [thread overview]
Message-ID: <8736nou2x5.fsf@dja-thinkpad.axtens.net> (raw)
In-Reply-To: <20190315043433.GC1671@sol.localdomain>
Eric Biggers <ebiggers@kernel.org> writes:
> Hi Daniel,
>
> On Fri, Mar 15, 2019 at 03:24:35PM +1100, Daniel Axtens wrote:
>> Hi Eric,
>>
>> >> The original assembly imported from OpenSSL has two copy-paste
>> >> errors in handling CTR mode. When dealing with a 2 or 3 block tail,
>> >> the code branches to the CBC decryption exit path, rather than to
>> >> the CTR exit path.
>> >
>> > So does this need to be fixed in OpenSSL too?
>>
>> Yes, I'm getting in touch with some people internally (at IBM) about
>> doing that.
>>
>> >> This leads to corruption of the IV, which leads to subsequent blocks
>> >> being corrupted.
>> >>
>> >> This can be detected with libkcapi test suite, which is available at
>> >> https://github.com/smuellerDD/libkcapi
>> >>
>> >
>> > Is this also detected by the kernel's crypto self-tests, and if not why not?
>> > What about with the new option CONFIG_CRYPTO_MANAGER_EXTRA_TESTS=y?
>>
>> It seems the self-tests do not catch it. To catch it, there has to be a
>> test where the blkcipher_walk creates a walk.nbytes such that
>> [(the number of AES blocks) mod 8] is either 2 or 3. This happens with
>> AF_ALG pretty frequently, but when I booted with self-tests it only hit
>> 1, 4, 5, 6 and 7 - it missed 0, 2 and 3.
>>
>> I don't have the EXTRA_TESTS option - I'm testing with 5.0-rc6. Is it in
>> -next?
>>
>> Regards,
>> Daniel
>
> The improvements I recently made to the self-tests are intended to catch exactly
> this sort of bug. They were just merged for v5.1, so try the latest mainline.
> This almost certainly would be caught by EXTRA_TESTS (and if not I'd want to
> know), but it may be caught by the regular self-tests now too.
Well, even the patched code fails with the new self-tests, so clearly
they're catching something! I'll investigate in more detail next week.
Regards,
Daniel
>
> - Eric
next prev parent reply other threads:[~2019-03-15 5:23 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-15 2:09 [PATCH] crypto: vmx - fix copy-paste error in CTR mode Daniel Axtens
2019-03-15 2:24 ` Eric Biggers
2019-03-15 4:24 ` Daniel Axtens
2019-03-15 4:34 ` Eric Biggers
2019-03-15 5:23 ` Daniel Axtens [this message]
2019-04-10 7:02 ` Eric Biggers
2019-04-11 14:47 ` Daniel Axtens
2019-04-11 17:40 ` Nayna
2019-04-13 3:41 ` Michael Ellerman
2019-05-06 15:53 ` Eric Biggers
2019-05-13 0:59 ` Herbert Xu
2019-05-13 11:39 ` Michael Ellerman
2019-05-14 17:35 ` Daniel Axtens
2019-05-15 3:53 ` Herbert Xu
2019-05-15 6:36 ` Daniel Axtens
2019-05-16 2:12 ` Daniel Axtens
2019-05-16 2:56 ` Eric Biggers
2019-05-16 5:28 ` Daniel Axtens
2019-03-18 8:41 ` Michael Ellerman
2019-03-18 9:13 ` Ard Biesheuvel
2019-03-19 0:52 ` Michael Ellerman
2019-03-18 6:03 ` Michael Ellerman
2019-03-20 8:40 ` Ondrej Mosnáček
2019-03-22 13:04 ` Herbert Xu
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