>> ... any machines that share user files via writable NFS mounts are
>> vulnerable. (Are vulnerable if you mount an NFS filesystem that is
>> writable to others.)
>
> No that is not true. You need to use root_squash for any semblance of
> security anyway. In that case you can also use squash_gids to prevent
> the attack.
Note that root_squash is default, squash_gids is not; there is no
recommendation to squash_gids staff. My machines do not know about
squash_gids (in "man exports", package nfs-kernel-server, versions
1.0-2woody3 or 1.0.6-3.1); I wonder if non-Debian OSs know.
(The issue of "real" users in group staff also remains.)
> ... I can design a [insecure] system ... Will that make it a Debian bug?
It is your bug if you make it insecure in the default, or in a common,
configuration. It is your bug if you do not warn against the insecure
settings.
Message-Id: <email address hidden>
Date: Thu, 17 Mar 2005 07:25:56 +1100
From: <email address hidden>
To: <email address hidden>, <email address hidden>
Cc: <email address hidden>
Subject: Re: Bug#299007: base-files: Insecure PATH
Bill Allombert <email address hidden> wrote:
>> ... any machines that share user files via writable NFS mounts are
>> vulnerable. (Are vulnerable if you mount an NFS filesystem that is
>> writable to others.)
>
> No that is not true. You need to use root_squash for any semblance of
> security anyway. In that case you can also use squash_gids to prevent
> the attack.
Note that root_squash is default, squash_gids is not; there is no
recommendation to squash_gids staff. My machines do not know about
squash_gids (in "man exports", package nfs-kernel-server, versions
1.0-2woody3 or 1.0.6-3.1); I wonder if non-Debian OSs know.
(The issue of "real" users in group staff also remains.)
> ... I can design a [insecure] system ... Will that make it a Debian bug?
It is your bug if you make it insecure in the default, or in a common,
configuration. It is your bug if you do not warn against the insecure
settings.
Cheers,
Paul Szabo <email address hidden> http:// www.maths. usyd.edu. au/u/psz/
School of Mathematics and Statistics University of Sydney Australia