Re: [PATCH 1/8] crypto: hash: add zero length message hash for shax and md5

[LABBE Corentin <montjoie.mailing@gmail.com>]

On Wed, Oct 14, 2015 at 06:08:02PM +0800, Herbert Xu wrote:
> On Mon, Oct 12, 2015 at 06:53:39PM +0200, LABBE Corentin wrote:
> > Some crypto drivers cannot process empty data message and return a
> > precalculated hash for md5/sha1/sha224/sha256.
> > 
> > This patch add thoses precalculated hash in include/crypto.
> > 
> > Signed-off-by: LABBE Corentin <clabbe.montjoie@gmail.com>
> > ---
> >  include/crypto/md5.h |  5 +++++
> >  include/crypto/sha.h | 20 ++++++++++++++++++++
> >  2 files changed, 25 insertions(+)
> > 
> > diff --git a/include/crypto/md5.h b/include/crypto/md5.h
> > index 146af82..6496ee0 100644
> > --- a/include/crypto/md5.h
> > +++ b/include/crypto/md5.h
> > @@ -13,6 +13,11 @@
> >  #define MD5_H2	0x98badcfeUL
> >  #define MD5_H3	0x10325476UL
> >  
> > +static const u8 md5_zero_message_hash[MD5_DIGEST_SIZE] = {
> > +	0xd4, 0x1d, 0x8c, 0xd9, 0x8f, 0x00, 0xb2, 0x04,
> > +	0xe9, 0x80, 0x09, 0x98, 0xec, 0xf8, 0x42, 0x7e,
> > +};
> > +
> 
> This potentially creates this structure in every file that includes
> md5.h.  How about putting it into md5_generic and exporting it?
> 

md5_generic does not exists, do you mean md5.c ?
I have made some try with EXPORT_SYMBOL() but without success.
Do you have any example of how to do that ?

Regards