linux-kernel - Re: Fwd: [crypto:master 60/60] arch/x86/crypto/ghash-clmulni-intel_glue.c:71:25: sparse: cast to restricted _

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Message-ID: <CAKv+Gu-ZKVz7JKhW9iWuZeKiRnyS3Z4uakPn2_UMW_CpSBgXkw@mail.gmail.com>
Date:	Fri, 11 Apr 2014 21:48:42 +0200
From:	Ard Biesheuvel <ard.biesheuvel@...aro.org>
To:	"gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>,
	Herbert Xu <herbert@...dor.apana.org.au>
Cc:	"linux-crypto@...r.kernel.org" <linux-crypto@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: Fwd: [crypto:master 60/60] arch/x86/crypto/ghash-clmulni-intel_glue.c:71:25:
 sparse: cast to restricted __be64

On 11 April 2014 18:03, gregkh@...uxfoundation.org
<gregkh@...uxfoundation.org> wrote:
> On Fri, Apr 04, 2014 at 10:11:19AM +0200, Ard Biesheuvel wrote:
>> Greg,
>>
>> This pertains to commit 8ceee72808d1 (crypto: ghash-clmulni-intel -
>> use C implementation for setkey()) that has been pulled by Linus
>> during the current merge window.
>>
>> It is missing two things:
>> - a cc to stable annotation
>> - a fix for the sparse warning below (change cast from __be64 to __force __be64)
>>
>> The reason for cc'ing stable on this patch is that it fixes a
>> potential data corruption issue where the ghash setkey() method uses
>> SSE registers without calling kernel_fpu_begin() first. This issue was
>> introduced by 0e1227d356e9b (crypto: ghash - Add PCLMULQDQ accelerated
>> implementation).
>>
>> So how would you like to proceed with this? Should I propose a new
>> patch somewhere?
>
> No problem, I'll apply this as-is.  But it doesn't apply to the
> 3.4-stable tree cleanly, can you send me a backported version if it's
> still needed there as well?
>

Yes, the code was broken from the start. 3.4 version is attached, the
only difference is the missing ENDPROC() at the end of the asm file.

In the mean time, Herbert has submitted a fix for the sparse warning,
but we settled on a different fix than I had suggested before.
https://git.kernel.org/cgit/linux/kernel/git/herbert/cryptodev-2.6.git/commit/?id=0ea481466d1c

Note that this code has not been tested (not by me, at least), so I
wouldn't suggest you take it straight away, but if you care about the
sparse warning, we could add a cc stable to it as well, I suppose.

Regards,
Ard.

View attachment "0001-crypto-ghash-clmulni-intel-use-C-implementation-for-.patch" of type "text/x-patch" (3386 bytes)