Re: GNU Coding Standards, automake, and the recent xz-utils backdoor

[Jacob Bachmeyer]

Russ Allbery wrote:
> [...]
>
> There is extensive ongoing discussion of this on debian-devel.  There's no
> real consensus in that discussion, but I think one useful principle that's
> emerged that doesn't disrupt the world *too* much is that the release
> tarball should differ from the Git tag only in the form of added files.
>   

From what I understand, the xz backdoor would have passed this check.  
The backdoor dropper was hidden in test data files that /were/ in the 
repository, and required code in the modified build-to-host.m4 to 
activate it.  The m4 files were not checked into the repository, instead 
being added (presumably by running autogen.sh with a rigged local m4 
file collection) while preparing the release.

Someone with a copy of a crocked release tarball should check if 
configure even had the backdoor "as released" or if the attacker was 
/depending/ on distributions to regenerate configure before packaging xz.


-- Jacob