RHBA-2015:0492 - Bug Fix Advisory

Topic

Updated grub2 packages that fix several bugs and add various enhancements are
now available for Red Hat Enterprise Linux 7.

Description

The grub2 packages provide version 2 of the Grand Unified Bootloader (GRUB), a
highly configurable and customizable bootloader with modular architecture. It
support a variety of kernel formats, file systems, computer architectures, and
hardware devices.

This update fixes the following bugs:

• Prior to this update, the basic bootloader configuration used alphabetical

order for selecting the default boot entry. As a consequence, the kernel-debug
boot entry was selected as default if it was included in the initial
installation. With this update, the bootloader sorting algorithm has been
improved and kernel-debug is no longer selected as the default boot entry.
(BZ#1065360)

• The GRUB2 bootloader loads from the /boot/grub2/ directory, where the GRUB2

environment block data is stored on Linux systems. However, on UEFI systems,
GRUB2 is not located in /boot/grub2/. Consequently, changes made to the GRUB2
environment block by GRUB2 utilities on a Linux system were previously not
reflected when using GRUB2 to boot a UEFI system. This update creates a symbolic
link between /boot/grub2/ and the location of GRUB2 on a UEFI system, which
prevents the described problem. (BZ#1119943, BZ#1127071)

• Due to a missing check for the IBM pSeries QEMU machine, the cursor was in

some cases not displayed when editing the kernel configuration during the boot
of an IBM Power Systems architecture guest in graphics mode. The missing check
has been added, and in the described scenario, the cursor is now visible as
expected. (BZ#1080051)

In addition, this update adds the following enhancements:

• Support for the little-endian variant of IBM Power Systems and the the 64-bit

ARM architecture has been added to GRUB2, which allows users to build and run
the grub2 packages on systems with these architectures. (BZ#967937, BZ#1125540)

• For increased clarity, the kernel names in the GRUB2 boot menu now also

contain the corresponding release version number of Red Hat Enterprise Linux.
(BZ#996794)

• Title matching has been added to the GRUB2 fallback variable. This allows

users to specify fallback boot entries based on their titles, where it was
previously only possible to specify the entries by their numbers. (BZ#1026084)

• The GRUB2 priority order when searching for the configuration path options

during a netboot on IBM Power Systems has been adjusted to be more reliable and
intuitive. The new order searches for a "grub.cfg-[OPTION]" file, where [OPTION]
can be the following, in order of priority: the client Universally Unique
Identifier (UUID), the client MAC address, and the client IP address. [OPTION]
can be also be a part of the IP address, with priority increasing proportionally
to the amount of characters from the IP address included. (BZ#1148652)

• The GRUB2 UEFI binary files have been enhanced to support regular expressions,

which enables the use of regular expressions in GRUB2 configuration files on
UEFI systems. (BZ#1125916)

Users of grub2 are advised to upgrade to these updated packages, which fix these
bugs and add these enhancements.

Solution

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

For details on how to apply this update, refer to:

https://access.redhat.com/articles/11258

Affected Products

• Red Hat Enterprise Linux Server 7 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 7.7 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 7.6 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 7.5 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 7.4 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 7.3 x86_64
• Red Hat Enterprise Linux Server from RHUI 7 x86_64
• Red Hat Enterprise Linux Server - AUS 7.7 x86_64
• Red Hat Enterprise Linux Server - AUS 7.6 x86_64
• Red Hat Enterprise Linux Server - AUS 7.4 x86_64
• Red Hat Enterprise Linux Server - AUS 7.3 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 7 x86_64
• Red Hat Enterprise Linux Workstation 7 x86_64
• Red Hat Enterprise Linux Desktop 7 x86_64
• Red Hat Enterprise Linux for Power, big endian 7 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 7.7 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 7.6 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 7.5 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 7.4 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 7.3 ppc64
• Red Hat Enterprise Linux for Scientific Computing 7 x86_64
• Red Hat Enterprise Linux Server - TUS 7.7 x86_64
• Red Hat Enterprise Linux Server - TUS 7.6 x86_64
• Red Hat Enterprise Linux Server - TUS 7.3 x86_64
• Red Hat Enterprise Linux EUS Compute Node 7.7 x86_64
• Red Hat Enterprise Linux EUS Compute Node 7.6 x86_64
• Red Hat Enterprise Linux EUS Compute Node 7.5 x86_64
• Red Hat Enterprise Linux EUS Compute Node 7.4 x86_64
• Red Hat Enterprise Linux EUS Compute Node 7.3 x86_64
• Red Hat Enterprise Linux for x86_64 - Update Services for SAP Solutions 7.7 x86_64
• Red Hat Enterprise Linux for x86_64 - Update Services for SAP Solutions 7.6 x86_64
• Red Hat Enterprise Linux for x86_64 - Update Services for SAP Solutions 7.4 x86_64
• Red Hat Enterprise Linux for x86_64 - Update Services for SAP Solutions 7.3 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support for IBM Power, big endian 7 ppc64

Fixes

• BZ - 1027833 - grub2-mkconfig does not honor GRUB_DISABLE_LINUX_UUID correctly
• BZ - 1148652 - grub2 sometimes uses the wrong config path when netbooting

CVEs

(none)

References

(none)