[Buildd-tools-devel] Bug#476332: Bug#476332: Bug#476332: schroot: Fails mysteriously when /etc/schroot/schroot.conf is a symlink

[Roger Leigh]

tags 476332 + fixed-upstream pending
thanks

Timothy G Abbott <tabbott at MIT.EDU> writes:

> The discussion of O_NOFOLLOW in the following might be helpful:
>
> http://www.linux-knowledge-portal.org/en/content.php?&content/programming/secprog2.html
>
> Most attacks that O_NOFOLLOW prevents can be executed with hard
> links; I believe the only exceptions are those in which the object
> being opened is a directory or other object that cannot be hard
> linked, and only then when the symlink is in the last component of
> the directory name.  Consequently, I believe O_NOFOLLOW is intended
> for programs like find, and is not useful for much else.
>
> Correct me if I'm wrong, but I believe schroot only reads
> configuration files from within /etc/, so it should not be
> vulnerable to the typical race condition attacks that O_NOFOLLOW is
> trying to prevent.

I think this makes sense, and I have removed O_FOLLOW from the open(2)
call.  This will be in the next schroot upload, hopefully soon (time
permitting).  If you want to get a fixed version right now, you can
check out the git repository

% git clone git://git.debian.org/git/buildd-tools/schroot.git schroot

This fix is on both the master and schroot-1.2 (stable for Lenny)
branches.


Regards,
Roger

-- 
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