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From: Milan Broz <gmazyland@gmail.com>
To: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Stephan Mueller <smueller@chronox.de>,
	Dmitry Vyukov <dvyukov@google.com>,
	syzkaller@googlegroups.com, davem@davemloft.net,
	linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org,
	kcc@google.com, glider@google.com, edumazet@google.com,
	sasha.levin@oracle.com, keescook@google.com,
	Ondrej Kozina <okozina@redhat.com>
Subject: Re: [PATCH 1/2] crypto: af_alg - Add nokey compatibility path
Date: Fri, 8 Jan 2016 19:21:12 +0100	[thread overview]
Message-ID: <568FFE18.6090900@gmail.com> (raw)
In-Reply-To: <20160108124851.GA5425@gondor.apana.org.au>

On 01/08/2016 01:48 PM, Herbert Xu wrote:
> On Mon, Jan 04, 2016 at 01:33:54PM +0100, Milan Broz wrote:
>>
>> - hmac() is now failing the same way (SETKEY after accept())
>> (I initially tested without two patches above, these are not in linux-next yet.)
>> This breaks all cryptsetup TrueCrypt support (and moreover all systems if
>> kernel crypto API is set as a default vcrypto backend - but that's not default).
> 
> Yes algif_hash would need the same compatibility patch and I'm
> working on that.

Ok, I fixed this already.

> 
>> - cipher_null before worked without setkey, now it requires to set key
>> (either before or after accept().
>> This was actually probably bad workaround in cryptsetup, anyway it will now cause
>> old cryptsetup-reencrypt tool failing with your patches.
>> (Try "cryptsetup benchmark -c cipher_null-ecb". I am not sure what to do here,
>> but not requiring setkey for "cipher" that has no key internally seems ok for me...)
> 
> Is cipher_null actually used in production or is this just a
> benchmark? Using the kernel crypto API to perform no encryption
> sounds crazy.

Except benchmarks (I do not care about this) we use cipher_null in cryptsetup-reencrypt
when adding encryption in-place (plaintext-only device is converted
to LUKS, cipher_null is used during conversion for original plainext device,
then offline converted to some real cipher with key).
(It reuses the same logic as re-encryption, IOW volume key change.)

So it is used in production but just for this specific case.

Thanks,
Milan

  reply	other threads:[~2016-01-08 18:21 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-12-17 12:59 GPF in lrw_crypt Dmitry Vyukov
2015-12-21 22:58 ` Stephan Mueller
2015-12-24  9:39 ` Herbert Xu
2015-12-24 11:03   ` Dmitry Vyukov
2015-12-25  7:40     ` [PATCH v2] crypto: algif_skcipher - Require setkey before accept(2) Herbert Xu
2015-12-28 13:39       ` Dmitry Vyukov
2015-12-29 13:24         ` Herbert Xu
2016-01-02 11:52       ` Milan Broz
2016-01-02 14:41         ` Milan Broz
2016-01-02 20:03           ` Stephan Mueller
2016-01-02 20:18             ` Milan Broz
2016-01-03  1:31               ` Herbert Xu
2016-01-03  9:42                 ` Milan Broz
2016-01-04  4:35                   ` [PATCH 1/2] crypto: af_alg - Add nokey compatibility path Herbert Xu
2016-01-04  4:36                     ` [PATCH 2/2] crypto: algif_skcipher " Herbert Xu
2016-01-04 12:33                     ` [PATCH 1/2] crypto: af_alg " Milan Broz
2016-01-08 12:48                       ` Herbert Xu
2016-01-08 18:21                         ` Milan Broz [this message]
2016-01-09  5:41                           ` Herbert Xu
2016-01-09 10:14                             ` Milan Broz
2016-01-11 13:26                               ` [PATCH 1/2] crypto: skcipher - Add crypto_skcipher_has_setkey Herbert Xu
2016-01-11 13:29                                 ` [PATCH 2/2] crypto: algif_skcipher - Add key check exception for cipher_null Herbert Xu
2016-01-11 14:59                                   ` Milan Broz
2016-01-08 13:28                       ` [PATCH 1/2] crypto: hash - Add crypto_ahash_has_setkey Herbert Xu
2016-01-08 13:31                         ` [PATCH 2/2] crypto: algif_hash - Require setkey before accept(2) Herbert Xu
2016-01-08 13:54                           ` kbuild test robot
2016-01-09 10:15                           ` Milan Broz

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