From: Yann Droneaud <ydroneaud@opteya•com>
To: Jeff King <peff@peff•net>
Cc: git@vger•kernel.org, Junio C Hamano <gitster@pobox•com>
Subject: Re: [PATCH 3/3] sha1: use char type for temporary work buffer
Date: Wed, 12 Sep 2012 22:37:10 +0200 [thread overview]
Message-ID: <1347482230.1961.4.camel@test.quest-ce.net> (raw)
In-Reply-To: <20120912183833.GA20795@sigill.intra.peff.net>
Le mercredi 12 septembre 2012 à 14:38 -0400, Jeff King a écrit :
> On Wed, Sep 12, 2012 at 12:30:45PM +0200, Yann Droneaud wrote:
>
> > The SHA context is holding a temporary buffer for partial block.
> >
> > This block must 64 bytes long. It is currently described as
> > an array of 16 integers.
> >
> > Signed-off-by: Yann Droneaud <ydroneaud@opteya•com>
> > ---
> > block-sha1/sha1.h | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/block-sha1/sha1.h b/block-sha1/sha1.h
> > index b864df6..d29ff6a 100644
> > --- a/block-sha1/sha1.h
> > +++ b/block-sha1/sha1.h
> > @@ -9,7 +9,7 @@
> > typedef struct {
> > unsigned long long size;
> > unsigned int H[5];
> > - unsigned int W[16];
> > + unsigned char W[64];
> > } blk_SHA_CTX;
>
> Wouldn't this break all of the code that is planning to index "W" by
> 32-bit words (see the definitions of setW in block-sha1/sha1.c)?
>
That's not the same "W" ... This part of the code is indeed unclear.
> You do not describe an actual problem in the commit message, but reading
> between the lines it would be "system X would like to use block-sha1,
> but has an "unsigned int" that is not 32 bits". IOW, an ILP64 type of
> architecture. Do you have some specific platform in mind?
>
> If that is indeed the problem, wouldn't the simplest fix be using
> uint32_t instead of "unsigned int"?
>
It's another way to fix this oddity, but not simpler.
> Moreover, would that be sufficient to run on such a platform? At the
> very least, "H" above would want the same treatment. And I would not be
> surprised if some of the actual code in block-sha1/sha1.c needed
> updating, as well.
>
ctx->H is actually used as an array of integer, so it would benefits of
being declared uint32_t for an ILP64 system. This fix would also be
required for blk_SHA1_Block() function.
Regards.
--
Yann Droneaud
OPTEYA
next prev parent reply other threads:[~2012-09-12 21:01 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-12 10:01 [PATCH 0/3] Janitor minor fixes on SHA1 Yann Droneaud
2012-09-12 10:01 ` [PATCH 1/3] sha1: update pointer and remaining length after subfunction call Yann Droneaud
2012-09-12 18:35 ` Junio C Hamano
2012-09-12 10:21 ` [PATCH 2/3] sha1: clean pointer arithmetic Yann Droneaud
2012-09-12 18:37 ` Junio C Hamano
2012-09-12 20:50 ` Yann Droneaud
2012-09-12 21:25 ` Bruce Korb
2012-09-12 10:30 ` [PATCH 3/3] sha1: use char type for temporary work buffer Yann Droneaud
2012-09-12 18:38 ` Jeff King
2012-09-12 20:37 ` Yann Droneaud [this message]
2012-09-12 21:04 ` Jeff King
2012-09-13 6:11 ` Yann Droneaud
2012-09-12 18:42 ` Junio C Hamano
2012-09-12 20:42 ` Yann Droneaud
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