RHSA-2011:1083

Problem Description:

Updated fuse packages that fix multiple security issues are now available
for Red Hat Enterprise Linux 6.

The Red Hat Security Response Team has rated this update as having moderate
security impact. Common Vulnerability Scoring System (CVSS) base scores,
which give detailed severity ratings, are available for each vulnerability
from the CVE links in the References section.

2. Relevant releases/architectures:

Red Hat Enterprise Linux Desktop (v. 6) - i386, x86_64
Red Hat Enterprise Linux Desktop Optional (v. 6) - i386, x86_64
Red Hat Enterprise Linux HPC Node (v. 6) - x86_64
Red Hat Enterprise Linux HPC Node Optional (v. 6) - x86_64
Red Hat Enterprise Linux Server (v. 6) - i386, ppc64, s390x, x86_64
Red Hat Enterprise Linux Workstation (v. 6) - i386, x86_64

3. Description:

FUSE (Filesystem in Userspace) can implement a fully functional file system
in a user-space program. These packages provide the mount utility,
fusermount, the tool used to mount FUSE file systems.

Multiple flaws were found in the way fusermount handled the mounting and
unmounting of directories when symbolic links were present. A local user in
the fuse group could use these flaws to unmount file systems, which they
would otherwise not be able to unmount and that were not mounted using
FUSE, via a symbolic link attack. (CVE-2010-3879, CVE-2011-0541,
CVE-2011-0542, CVE-2011-0543)

Note: The util-linux-ng RHBA-2011:0699 update must also be installed to
fully correct the above flaws.

All users should upgrade to these updated packages, which contain
backported patches to correct these issues.

4. Solution:

Before applying this update, make sure all previously-released errata
relevant to your system have been applied.

This update is available via the Red Hat Network. Details on how to
use the Red Hat Network to apply this update are available at
https://access.redhat.com/kb/docs/DOC-11259

5. Bugs fixed (http://bugzilla.redhat.com/):

651183 - CVE-2010-3879 CVE-2011-0541 CVE-2011-0542 CVE-2011-0543 fuse: unprivileged user can unmount arbitrary locations via symlink attack