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From: Ard Biesheuvel <ard.biesheuvel@linaro.org>
To: Herbert Xu <herbert@gondor.apana.org.au>
Cc: "open list:HARDWARE RANDOM NUMBER GENERATOR CORE" 
	<linux-crypto@vger.kernel.org>
Subject: Re: [v2 PATCH] crypto: skcipher - Unmap pages after an external error
Date: Fri, 6 Sep 2019 18:32:29 -0700	[thread overview]
Message-ID: <CAKv+Gu85brKkLPJLs_uk5F6fO=+hiej7KojLH8deDtzTeYbUqA@mail.gmail.com> (raw)
In-Reply-To: <20190907011940.GA8663@gondor.apana.org.au>

On Fri, 6 Sep 2019 at 18:19, Herbert Xu <herbert@gondor.apana.org.au> wrote:
>
> On Fri, Sep 06, 2019 at 05:52:56PM -0700, Ard Biesheuvel wrote:
> >
> > With this change, we still copy out the output in the
> > SKCIPHER_WALK_COPY or SKCIPHER_WALK_SLOW cases. I'd expect the failure
> > case to only do the kunmap()s, but otherwise not make any changes that
> > are visible to the caller.
>
> I don't think it matters.  After all, for the fast/common path
> whatever changes that have been made will be visible to the caller.
> I don't see the point in making the slow-path different in this
> respect.  It also makes no sense to optimise specifically for the
> uncommon error case on the slow-path.
>

The point is that doing

skcipher_walk_virt(&walk, ...);
skcipher_walk_done(&walk, -EFOO);

may clobber your data if you are executing in place (unless I am
missing something)

If skcipher_walk_done() is called with an error, it should really just
clean up after it self, but not copy back the unknown contents of
temporary buffers.

  reply	other threads:[~2019-09-07  1:32 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-21 14:32 [PATCH 00/17] crypto: arm/aes - XTS ciphertext stealing and other updates Ard Biesheuvel
2019-08-21 14:32 ` [PATCH 01/17] crypto: arm/aes - fix round key prototypes Ard Biesheuvel
2019-08-21 14:32 ` [PATCH 02/17] crypto: arm/aes-ce - yield the SIMD unit between scatterwalk steps Ard Biesheuvel
2019-08-21 14:32 ` [PATCH 03/17] crypto: arm/aes-ce - switch to 4x interleave Ard Biesheuvel
2019-08-21 14:32 ` [PATCH 04/17] crypto: arm/aes-ce - replace tweak mask literal with composition Ard Biesheuvel
2019-08-21 14:32 ` [PATCH 05/17] crypto: arm/aes-neonbs " Ard Biesheuvel
2019-08-21 14:32 ` [PATCH 06/17] crypto: arm64/aes-neonbs " Ard Biesheuvel
2019-08-21 14:32 ` [PATCH 07/17] crypto: arm64/aes-neon - limit exposed routines if faster driver is enabled Ard Biesheuvel
2019-08-21 14:32 ` [PATCH 08/17] crypto: skcipher - add the ability to abort a skcipher walk Ard Biesheuvel
2019-08-30  8:03   ` Herbert Xu
2019-08-31 18:01     ` Ard Biesheuvel
2019-09-03  6:54       ` crypto: skcipher - Unmap pages after an external error Herbert Xu
2019-09-03  7:05         ` crypto: ablkcipher " Herbert Xu
2019-09-03  7:09           ` crypto: blkcipher " Herbert Xu
2019-09-03 13:50         ` crypto: skcipher " Eric Biggers
2019-09-03 22:36           ` Herbert Xu
2019-09-05  5:22             ` Eric Biggers
2019-09-05  5:40               ` Herbert Xu
2019-09-06  1:57                 ` Eric Biggers
2019-09-06  2:15                   ` Herbert Xu
2019-09-06  3:13                     ` [v2 PATCH] " Herbert Xu
2019-09-07  0:52                       ` Ard Biesheuvel
2019-09-07  1:19                         ` Herbert Xu
2019-09-07  1:32                           ` Ard Biesheuvel [this message]
2019-09-07  1:56                             ` Herbert Xu
2019-09-07  2:14                               ` Ard Biesheuvel
2019-08-21 14:32 ` [PATCH 09/17] crypto: arm64/aes-cts-cbc-ce - performance tweak Ard Biesheuvel
2019-08-21 14:32 ` [PATCH 10/17] crypto: arm64/aes-cts-cbc - move request context data to the stack Ard Biesheuvel
2019-08-21 14:32 ` [PATCH 11/17] crypto: arm64/aes - implement support for XTS ciphertext stealing Ard Biesheuvel
2019-08-21 14:32 ` [PATCH 12/17] crypto: arm64/aes-neonbs - implement ciphertext stealing for XTS Ard Biesheuvel
2019-08-21 14:32 ` [PATCH 13/17] crypto: arm/aes-ce " Ard Biesheuvel
2019-08-21 14:32 ` [PATCH 14/17] crypto: arm/aes-neonbs " Ard Biesheuvel
2019-08-21 14:32 ` [PATCH 15/17] crypto: arm/aes-ce - implement ciphertext stealing for CBC Ard Biesheuvel
2019-09-30 16:32   ` Guenter Roeck
2019-09-30 18:19     ` Ard Biesheuvel
2019-08-21 14:32 ` [PATCH 16/17] crypto: testmgr - add test vectors for XTS ciphertext stealing Ard Biesheuvel
2019-08-21 14:32 ` [PATCH 17/17] crypto: testmgr - Add additional AES-XTS vectors for covering CTS Ard Biesheuvel

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