(RHSA-2011:1534) Low: nfs-utils security, bug fix, and enhancement update

The nfs-utils packages provide a daemon for the kernel Network File System
(NFS) server, and related tools such as the mount.nfs, umount.nfs, and
showmount programs.

A flaw was found in the way nfs-utils performed IP based authentication of
mount requests. In configurations where a directory was exported to a group
of systems using a DNS wildcard or NIS (Network Information Service)
netgroup, an attacker could possibly gain access to other directories
exported to a specific host or subnet, bypassing intended access
restrictions. (CVE-2011-2500)

It was found that the mount.nfs tool did not handle certain errors
correctly when updating the mtab (mounted file systems table) file. A local
attacker could use this flaw to corrupt the mtab file. (CVE-2011-1749)

This update also fixes several bugs and adds an enhancement. Documentation
for these bug fixes and the enhancement will be available shortly from the
Technical Notes document, linked to in the References section.

Users of nfs-utils are advised to upgrade to these updated packages, which
contain backported patches to resolve these issues and add this
enhancement. After installing this update, the nfs service will be
restarted automatically.