RHSA-2011:1083 - Security Advisory

Topic

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.

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.

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

Affected Products

• Red Hat Enterprise Linux Server 6 x86_64
• Red Hat Enterprise Linux Server 6 i386
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 6.1 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 6.1 i386
• Red Hat Enterprise Linux Workstation 6 x86_64
• Red Hat Enterprise Linux Workstation 6 i386
• Red Hat Enterprise Linux Desktop 6 x86_64
• Red Hat Enterprise Linux Desktop 6 i386
• Red Hat Enterprise Linux for IBM z Systems 6 s390x
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 6.1 s390x
• Red Hat Enterprise Linux for Power, big endian 6 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 6.1 ppc64
• Red Hat Enterprise Linux for Scientific Computing 6 x86_64
• Red Hat Enterprise Linux Server from RHUI 6 x86_64
• Red Hat Enterprise Linux Server from RHUI 6 i386
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.1 x86_64
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.1 i386
• Red Hat Virtual Storage Appliance (from RHUI) 6.1 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support (for IBM z Systems) 6 s390x

Fixes

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

CVEs

• CVE-2010-3879
• CVE-2011-0542
• CVE-2011-0543
• CVE-2011-0541

References

• https://access.redhat.com/security/updates/classification/#moderate
• https://rhn.redhat.com/errata/RHBA-2011-0699.html