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 19:14:40 -0700 [thread overview]
Message-ID: <CAKv+Gu9ark7z3=x+QC_z3TzfTBgvbWWd4xY7-yNYcL8C0BAmHg@mail.gmail.com> (raw)
In-Reply-To: <20190907015559.GA10773@gondor.apana.org.au>
On Fri, 6 Sep 2019 at 18:56, Herbert Xu <herbert@gondor.apana.org.au> wrote:
>
> On Fri, Sep 06, 2019 at 06:32:29PM -0700, Ard Biesheuvel wrote:
> >
> > 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)
>
> You mean encrypting in place? If you're encrypting in place you're
> usually on the zero-copy fast path so whatever is left-behind by the
> algorithm will be visible anyway without any copying.
>
> > 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.
>
> We're not copying uninitialised kernel memory. The temporary space
> starts out as a copy of the source and we're just copying it to the
> destination.
>
Right. In that case, I guess it is safe.
I've tested my XTS/CTS changes (which call skcipher_walk_done() with
an error value in some cases) with Eric's fuzz testing enabled, and it
all works fine, so
Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Thanks,
Ard.
next prev parent reply other threads:[~2019-09-07 2:15 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
2019-09-07 1:56 ` Herbert Xu
2019-09-07 2:14 ` Ard Biesheuvel [this message]
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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