Samba and a crypto library

[Andreas Schneider]

On Thursday, November 19, 2015 07:41:52 AM Andrew Bartlett wrote:
> On Wed, 2015-11-18 at 08:42 -0800, Jeremy Allison wrote:
> > On Wed, Nov 18, 2015 at 08:03:31AM +0100, Andreas Schneider wrote:
> > > On Tuesday 17 November 2015 18:02:33 Andreas Schneider wrote:
> > > > Hello,
> > > > 
> > > > I'm currently working on migrating our MS-BRKP implementation to
> > > > GnuTLS to
> > > > get rid of the Heimdal dependency for MIT Kerberos support. I've
> > > > already
> > > > migrated everthing which is certificate related to GnuTLS.
> > > > However there
> > > > are SHA and HMAC functions which are still used from Heimdal.
> > > > 
> > > > To do this I would like to add a depenency to a crypto library.
> > > > As we are
> > > > already using GnuTLS for some parts of the could, I would like to
> > > > use GNU
> > > > Nettle for the low level crypto stuff. GnuTLS depends on
> > > > libnettle for the
> > > > low level crypto.
> > > > 
> > > > https://www.lysator.liu.se/~nisse/nettle/nettle.html
> > > > 
> > > > https://git.lysator.liu.se/nettle/nettle
> > > > 
> > > > The license is LGPLv3, GPLv2 and GPLv3.
> > > > 
> > > > The crypto operations are mostly written in assembler and also
> > > > use cpu
> > > > optimized versions like aesni.
> > > > 
> > > > It is really up to date and implement state of the art crypto
> > > > like chacha-
> > > > poly1305, Curve25519 etc. The development seems active and
> > > > healthy.
> > > > 
> > > > If we agree I would also suggset not only to use it for MS-BRKP
> > > > but also
> > > > replace lib/crypto in future.
> > > 
> > > Ok, then I will go ahead. I guess people will start to discuss and
> > > complain as
> > > soon as I remove lib/crypto ;)
> > 
> > I took a look at it and it seemed fine :-). Just didn't
> > get chance to reply. Does it integrate with crypto-offload
> > engines ?
> 
> Both it and libnettle seem to do it for some ciphers.  See
> lib/crypto/REQUIREMENTS for some notes we collected earlier this year,
> and see some of the other threads titled 'crypto' for the other work
> that was done to use a possible pluggable API.
> 
> In particular see:
> https://git.samba.org/?p=metze/samba/wip.git;a=shortlog;h=refs/heads/ma
> ster3-smb-crypto
> 
> That said, I'm happy with just expanding our dependency on gnutls for
> now.

I've changed the backupkey torture test to only use gnutls API. I will do the 
same for the rpc server now.

I've discussed libnettle with Metze and Volker today and I've also talked to 
Nikos a collegue of mine and the maintainer for GnuTLS. The project is healthy 
and has a lot of improvements for assembler implementation of the ciphers so 
they are faster.

Also the libnettle API is very good and documented. I prefer it over OpenSSL.

The only cipher missing is aes-cmac but I'm sure the maintainer is open to a 
contribution of that cipher.


Cheers,


	-- andreas