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Re: Why back-porting patches to stable instead of releasing a new package.



On Sat, Aug 16, 2003 at 09:34:20AM +0200, Thomas Viehmann wrote:
> Andrew Pimlott wrote:
> > On Wed, Jul 23, 2003 at 09:10:01AM -0400, Matt Zimmerman wrote:
> > 
> >>- Security advisories and the associated packages should fix security
> >>  vulnerabilities and nothing else.
> > Have you perhaps seen
> ...
> > ?  I think it's a fairly convincing critique of this policy.  I'm
> Chances are I never will, because I'm not going to subscribe anytime soon. You
> could at least allude to the major points you find that convincing.

Sorry, I completely forgot LWN is a closed site.  I believe the link
will be freely available next Thursday.  ISTR that Debian developers
have a subscription compliments of HP (?), in case you're a Debian
developer.

The article discusses this advisory:

    http://lwn.net/Articles/42452/

Both problems apparently were fixed some time ago upstream.

The discussion following the article seems to be unrestricted:

   http://lwn.net/Articles/44409/

The first comment makes the point,

    That's why OpenBSD doesn't announce security holes they find
    when they fix bugs in inherited packages.

Debian isn't OpenBSD, but I think most would agree that OpenBSD has
a good understanding of the problem.

> > sure there are many security holes in woody that are fixed in the
> > latest stable upstream release.[1]  Debian's policy assures that all
> > well-publicized bugs get patched, but that doesn't mean that others
> > don't slip through the cracks.  A capable cracker targeting a Debian
> > stable system has a simple algorithm: browse upstream changelogs for
> > closed holes that weren't publicized.
> Responsible Upstreams will publicize security holes, especially the easily
> exploitable ones.

Is Postfix (the subject of the above link) responsible?  The
upstream of the bug I know about is also generally considered
responsible.  When you fix a lot of bugs, it takes a lot of time to
check every one for exploitability.  Whether you think upstreams
should check or not, it's almost impossible for them to do a perfect
(or even close to perfect) job.

> If it's in the Changelog, it would be the Debian package
> maintainer's task to find it and see that it gets a security fix.

It's harder than it sounds.  Besides, security isn't somewhere you
want to play the blame game.  You just want to close the holes.

If a Debian developer watches the Changelog and applies only
"obvious" bug fixes, and tells the security team, "there are
probable some security holes fixed in here", will they accept it?  I
think they should.

> Also, random updates to new upstream versions will break all kinds of
> (rightfully) expected behavior,

This is an obvious trade-off, but it is manageable.  Ideally,
updates should come from a feature-frozen branch.  If upstream
doesn't have one, they should be persuaded, or distributions should
create one.  A well-controlled bug-fix-only branch is very reliable.

> > [1] Actually, I know of one about which I am communicating with the
> > maintainer.
> That's a fairly unconvincing empirical basis.

That's why it's a footnote, not part of the main text.

Andrew



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