Sourceware mitigating and preventing the next xz-backdoor

[Martin Uecker]

Am Mittwoch, dem 03.04.2024 um 16:00 +0200 schrieb Michael Matz:
> Hello,
> 
> On Wed, 3 Apr 2024, Martin Uecker via Gcc wrote:
> 
> > > > Seems reasonable, but note that it wouldn't make any difference to
> > > > this attack.  The liblzma library was modified to corrupt the sshd
> > > > binary, when sshd was linked against liblzma.  The actual attack
> > > > occurred via a connection to a corrupt sshd.  If sshd was running as
> > > > root, as is normal, the attacker had root access to the machine.  None
> > > > of the attacking steps had anything to do with having root access
> > > > while building or installing the program.
> > 
> > There does not seem a single good solution against something like this.
> > 
> > My take a way is that software needs to become less complex. Do 
> > we really still need complex build systems such as autoconf?
> 
> Do we really need complex languages like C++ to write our software in?  
> SCNR :)  

Probably not.

> Complexity lies in the eye of the beholder, but to be honest in 
> the software that we're dealing with here, the build system or autoconf 
> does _not_ come to mind first when thinking about complexity.

The backdoor was hidden in a complicated autoconf script...

> 
> (And, FWIW, testing for features isn't "complex".  And have you looked at 
> other build systems?  I have, and none of them are less complex, just 
> opaque in different ways from make+autotools).

I ask a very specific question: To what extend is testing 
for features instead of semantic versions and/or supported
standards still necessary?  This seems like a problematic approach
that  may have been necessary decades ago, but it seems it may be
time to move on.


Martin