Re: CVE Request for glusterfs: fuse check return value of setuid

[cve-assign () mitre org]

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> does it hinge upon the util-linux "aren't running suid" behaviour

Our initial thought is that, if a mount program doesn't care about the
real UID, then the glusterfs setuid(0) calls are probably unnecessary
and checking their return values probably doesn't accomplish anything.
One conceivable exception is a mount implementation that maintains an
association between each mount entry and the real UID that established
that mount entry, and also requires a special option for root to
unmount a filesystem that was mounted by a non-root user. For example,
if a setuid(0) call failed during a mount, then there could be an
association between /home/alice/fs1 and alice's real UID. Here, root
would be authorized to unmount /home/alice/fs1, but the specific
/bin/umount command-line options hardcoded in glusterfs would not
work. Therefore, alice might be forced to leave /home/alice/fs1
mounted unless she were able to cause a setuid(0) call to fail during
an unmount. This might have security relevance if /home/alice/fs1
contained private files, and alice's original intention was to have
that filesystem mounted for a very short time.

We don't know if any real mount software meets those requirements.

- -- 
CVE assignment team, MITRE CVE Numbering Authority
M/S M300
202 Burlington Road, Bedford, MA 01730 USA
[ PGP key available through http://cve.mitre.org/cve/request_id.html ]
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