RFC: PPP MPPE merge into kernel 2.6

RFC: PPP MPPE merge into kernel 2.6

[James Cameron]

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I'd like to open a discussion on the merge of the PPP MPPE support with
kernel 2.6.  What can be done to achieve it?  What is hindering it?
What can we do to remove the roadblocks?

MPPE is Microsoft's encryption scheme for PPP links.

The Linux MPPE support consists of five new source files, and patches to
ppp.c, ppp_generic.c and ppp-comp.h, and can be found in the CVS
repository for the PPP project in linux/mppe.  The patches are relative
to 2.2 and 2.4.  See http://samba.org/ftp/unpacked/ppp/linux/mppe/

The author is Frank Cusack <frank@google.com>, and the code is covered
by the "BSD without advertisement clause" license.  Frank released this
around March 2002.  See http://samba.org/ftp/unpacked/ppp/README.MPPE

MPPE support is used by PPTP.  People who wish to use PPTP on their
system often have to modify their kernel to add MPPE support.  PPTP is
not a particularly good tunnelling protocol, but many people are
required to use it as a condition of employment.  In particular, MPPE
is not applied to non-data packets in the PPP stream, apparently by
design.

Many distributions do not ship MPPE support (e.g. Red Hat).  Some
distributions have shipped an older version of MPPE support covered by
the OpenSSL license, which is incompatible with the kernel license (e.g.
SuSE, Mandrake).  Some provide a patch (e.g. Debian).

The PPTP projects have adapted to the lack of MPPE support in the
upstream kernel by providing custom kernels, version specific patches,
module build scripts, and even binary modules.  

Since the release of 2.6.0, two or three people have provided me with
patches relative to 2.6.

The OpenSSL licensed MPPE support was a separate implementation, and was
provided as a patch to 2.4.1.  This was adopted by SuSE and Mandrake for
their kernels, but is incompatible with the MPPE support in the newly
released PPP 2.4.2.

It would be good to unify this situation and remove some of the pain.

Some effort has also been put into MPPC support, but as MPPC is covered
by a patent I'm not proposing that.

I'm the PPTP client project leader.

--
James Cameron                         http://quozl.netrek.org/
HP Open Source, Volunteer             http://opensource.hp.com/
PPTP Client Project, Release Engineer http://pptpclient.sourceforge.net/

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Re: RFC: PPP MPPE merge into kernel 2.6

[Chris Wilson]

Hi James,

> I'd like to open a discussion on the merge of the PPP MPPE support with
> kernel 2.6.  What can be done to achieve it?  What is hindering it?
> What can we do to remove the roadblocks?

Sounds like an excellent idea, but it may be too late to have anything 
other than bug fixes merged into 2.6. 2.7/2.8 should be possible, though.

I think there is a strong argument for the support being in the kernel,
given the number of other devices that have to support it, the obvious
end-user demand (witness pptpclient and poptop :-) and the hassle for
users of finding the right patch and patching their kernels (given the
patch confusion which exists). Some users are having problems with
patching due to failed hunks, and Joe Bloggs shouldn't have to worry about 
that.

Let's go for it :-) What do we have to lose?

Cheers, Chris.
-- 
_  __ __     _
 / __/ / ,__(_)_  | Chris Wilson -- UNIX Firewall Lead Developer |
/ (_  ,\/ _/ /_ \ | NetServers.co.uk http://www.netservers.co.uk |
\__/_/_/_//_/___/ | 21 Signet Court, Cambridge, UK. 01223 576516 |

Re: RFC: PPP MPPE merge into kernel 2.6

[Pasi Kärkkäinen]

On Fri, Jan 30, 2004 at 10:32:59AM +0000, Chris Wilson wrote:
> Hi James,
> 
> > I'd like to open a discussion on the merge of the PPP MPPE support with
> > kernel 2.6.  What can be done to achieve it?  What is hindering it?
> > What can we do to remove the roadblocks?
> 
> Sounds like an excellent idea, but it may be too late to have anything 
> other than bug fixes merged into 2.6. 2.7/2.8 should be possible, though.
> 
> I think there is a strong argument for the support being in the kernel,
> given the number of other devices that have to support it, the obvious
> end-user demand (witness pptpclient and poptop :-) and the hassle for
> users of finding the right patch and patching their kernels (given the
> patch confusion which exists). Some users are having problems with
> patching due to failed hunks, and Joe Bloggs shouldn't have to worry about 
> that.
> 
> Let's go for it :-) What do we have to lose?
> 

Should the MPPC support (by Jan Dubiec) be included as well?
http://www.polbox.com/h/hs001/

It also contains some additions to the MPPE support.

-- Pasi Kärkkäinen
       
                                   ^
                                .     .
                                 Linux
                              /    -    \
                             Choice.of.the
                           .Next.Generation.

Re: RFC: PPP MPPE merge into kernel 2.6

[James Cameron]

On Mon, Feb 02, 2004 at 12:43:29PM +0200, Pasi K?rkk?inen wrote:
> Should the MPPC support (by Jan Dubiec) be included as well?
> http://www.polbox.com/h/hs001/

I don't think so, due to the software patent issue.  While my personal
belief differs, while working for HP I am constrained to follow patents.

> It also contains some additions to the MPPE support.

Yes, 56-bit keys.  I haven't found any demand for that.  The options are
also slightly different, though that would be easy to ignore.

Jan's work though looks robust and thorough.  Having the work hosted
like that, with current patches for all current kernels, is more than
Frank is doing.  ;-)

-- 
James Cameron                         http://quozl.netrek.org/
HP Open Source, Volunteer             http://opensource.hp.com/
PPTP Client Project, Release Engineer http://pptpclient.sourceforge.net/