Re: R: Linux kernel source archive vulnerable

David Wagner
2006-09-13T01:18:05Z

Rene Scharfe wrote:
>[details on how GNU tar works, snipped]

Again, you miss my point. I already know how tar works, but that's not
my point. Why is it that people are so unwilling to address the real
issue here? Let's try a few facts:

(a) The Linux kernel tar archive contains files with world-writeable
permissions.

(b) There is no need for those files to have world-writeable
permissions. It doesn't serve any particular purpose. If the
permissions in the tar archive were changed to be not world-writeable,
no harm would be done.

(c) Some users may get screwed over by virtue of the fact that those
files are listed in the tar archive with world-writeable permissions.
(Sure, if every user was an expert on "tar" and on security, then
maybe no one would get screwed over. But in the real world, that's
not the case.)

(d) Consequently, the format of the Linux kernel tar archive is
exposing some users to unnecessary riskis.

(e) The Linux kernel folks could take a quick and easy step that
would eliminate this risk. That step would involve storing the
files in the tar archive with permissions that were more reasonable
(not world-writeable would be a good start!). This step wouldn't
hurt anyone. There's no downside.

(f) Yet the Linux kernel folks refuse to take this step, and any
time someone mentions that there is something the Linux kernel folks
could do about the problem, someone tries to change the topic to
something else (e.g., complaints about bugs in GNU tar, suggestions
that the user should invoke tar with some other option, claims that
this question has been addressed before, you name it).

So why is it that the tar archive is structured this way? Why are
the Linux kernel folks unnecessarily exposing their users to risk?
What purpose, exactly, does it serve to have these files stored with
world-writeable permissions?

Folks on the Linux kernel mailing list seem to be reluctant to admit these
facts forthrightly. The posts I've seen mostly seem to have little or
no sympathy for users who get screwed over. The attitude seems to be:
if you get screwed over, it's your fault and your problem. Why is that?
If there is a simple step that Linux developers can take to eliminate
this risk, why is there such reluctance to take it, and why is there
such eagerness to point the finger at someone else?

The way I see it, storing files in a tar archive with world-writeable
permissions is senseless. Why do such a strange thing on purpose?

It all seems thoroughly mysterious to me.