(RHSA-2014:1801) Moderate: shim security update

Shim is the initial UEFI bootloader that handles chaining to a trusted full
bootloader under secure boot environments.

A heap-based buffer overflow flaw was found the way shim parsed certain
IPv6 addresses. If IPv6 network booting was enabled, a malicious server
could supply a crafted IPv6 address that would cause shim to crash or,
potentially, execute arbitrary code. (CVE-2014-3676)

An out-of-bounds memory write flaw was found in the way shim processed
certain Machine Owner Keys (MOKs). A local attacker could potentially use
this flaw to execute arbitrary code on the system. (CVE-2014-3677)

An out-of-bounds memory read flaw was found in the way shim parsed certain
IPv6 packets. A specially crafted DHCPv6 packet could possibly cause shim
to crash, preventing the system from booting if IPv6 booting was enabled.
(CVE-2014-3675)

Red Hat would like to thank the SUSE Security Team for reporting these
issues.

All shim users are advised to upgrade to these updated packages, which
contain backported patches to correct these issues. The system must be
rebooted for this update to take effect.