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Security Advisory Low: grub2 security, bug fix, and enhancement update

Advisory: RHSA-2015:2401-2
Type: Security Advisory
Severity: Low
Issued on: 2015-11-19
Last updated on: 2015-11-19
Affected Products: Red Hat Enterprise Linux Desktop (v. 7)
Red Hat Enterprise Linux HPC Node (v. 7)
Red Hat Enterprise Linux Server (v. 7)
Red Hat Enterprise Linux Workstation (v. 7)
CVEs (cve.mitre.org): CVE-2015-5281

Details

Updated grub2 packages that fix one security issue, several bugs, and add
one enhancement are now available for Red Hat Enterprise Linux 7.

Red Hat Product Security has rated this update as having Low security
impact. A Common Vulnerability Scoring System (CVSS) base score, which
gives a detailed severity rating, is available from the CVE link in the
References section.

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

It was discovered that grub2 builds for EFI systems contained modules that
were not suitable to be loaded in a Secure Boot environment. An attacker
could use this flaw to circumvent the Secure Boot mechanisms and load
non-verified code. Attacks could use the boot menu if no password was set,
or the grub2 configuration file if the attacker has root privileges on the
system. (CVE-2015-5281)

This update also fixes the following bugs:

* In one of the earlier updates, GRUB2 was modified to escape forward slash
(/) characters in several different places. In one of these places, the
escaping was unnecessary and prevented certain types of kernel command-line
arguments from being passed to the kernel correctly. With this update,
GRUB2 no longer escapes the forward slash characters in the mentioned
place, and the kernel command-line arguments work as expected. (BZ#1125404)

* Previously, GRUB2 relied on a timing mechanism provided by legacy
hardware, but not by the Hyper-V Gen2 hypervisor, to calibrate its timer
loop. This prevented GRUB2 from operating correctly on Hyper-V Gen2.
This update modifies GRUB2 to use a different mechanism on Hyper-V Gen2 to
calibrate the timing. As a result, Hyper-V Gen2 hypervisors now work as
expected. (BZ#1150698)

* Prior to this update, users who manually configured GRUB2 to use the
built-in GNU Privacy Guard (GPG) verification observed the following error
on boot:

alloc magic is broken at [addr]: [value] Aborted.

Consequently, the boot failed. The GRUB2 built-in GPG verification has been
modified to no longer free the same memory twice. As a result, the
mentioned error no longer occurs. (BZ#1167977)

* Previously, the system sometimes did not recover after terminating
unexpectedly and failed to reboot. To fix this problem, the GRUB2 packages
now enforce file synchronization when creating the GRUB2 configuration
file, which ensures that the required configuration files are written to
disk. As a result, the system now reboots successfully after crashing.
(BZ#1212114)

* Previously, if an unconfigured network driver instance was selected and
configured when the GRUB2 bootloader was loaded on a different instance,
GRUB2 did not receive notifications of the Address Resolution Protocol
(ARP) replies. Consequently, GRUB2 failed with the following error message:

error: timeout: could not resolve hardware address.

With this update, GRUB2 selects the network driver instance from which it
was loaded. As a result, ARP packets are processed correctly. (BZ#1257475)

In addition, this update adds the following enhancement:

* Sorting of GRUB2 boot menu has been improved. GRUB2 now uses the
rpmdevtools package to sort available kernels and the configuration file is
being generated correctly with the most recent kernel version listed at the
top. (BZ#1124074)

All grub2 users are advised to upgrade to these updated packages, which
contain backported patches to correct these issues and add this
enhancement.


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

Updated packages

Red Hat Enterprise Linux Desktop (v. 7)

SRPMS:
grub2-2.02-0.29.el7.src.rpm
File outdated by:  RHBA-2016:2336
    MD5: 6f1b37e564836fce02a731be50d95d9b
SHA-256: 1138d2be2fc12f399d16726f03fc7a09390ff61adca72b476b701af847d8755b
 
x86_64:
grub2-2.02-0.29.el7.x86_64.rpm
File outdated by:  RHBA-2016:2336
    MD5: b8232630ee1cdc45edc328b02b8c867b
SHA-256: 20910d54ed0d7956d3948235326a65bff4a510bcfbaee3ec120d17b1b904afe8
grub2-debuginfo-2.02-0.29.el7.x86_64.rpm
File outdated by:  RHBA-2016:0003
    MD5: 22e39a73491231dcd762eb35bed4f4be
SHA-256: 08ae48b99cebe091244d69b16187e3903ba5ef5be2c5ca132ee52bca4040fd3d
grub2-efi-2.02-0.29.el7.x86_64.rpm
File outdated by:  RHBA-2016:2336
    MD5: 630618de4e6a177db5d67ad9a9f0b56b
SHA-256: a2ae5a4ee0738578f0cfb7efd70692314766baa4d76cd65c762e3b996d716710
grub2-efi-modules-2.02-0.29.el7.x86_64.rpm
File outdated by:  RHBA-2016:0003
    MD5: abfdccd26500a165024bf3e2b676e5ab
SHA-256: 1790114dee473fe434036ddf3f54f61f79c2d0e2188ad2a63f84ce0891f3e722
grub2-tools-2.02-0.29.el7.x86_64.rpm
File outdated by:  RHBA-2016:2336
    MD5: 33d686e5a208b775178f08820d40cd4c
SHA-256: d701afcaa763b1364062b7aa8a004807954b8990025c29c2b9fb574e0312f76c
 
Red Hat Enterprise Linux HPC Node (v. 7)

SRPMS:
grub2-2.02-0.29.el7.src.rpm
File outdated by:  RHBA-2016:2336
    MD5: 6f1b37e564836fce02a731be50d95d9b
SHA-256: 1138d2be2fc12f399d16726f03fc7a09390ff61adca72b476b701af847d8755b
 
x86_64:
grub2-2.02-0.29.el7.x86_64.rpm
File outdated by:  RHBA-2016:2336
    MD5: b8232630ee1cdc45edc328b02b8c867b
SHA-256: 20910d54ed0d7956d3948235326a65bff4a510bcfbaee3ec120d17b1b904afe8
grub2-debuginfo-2.02-0.29.el7.x86_64.rpm
File outdated by:  RHBA-2016:0003
    MD5: 22e39a73491231dcd762eb35bed4f4be
SHA-256: 08ae48b99cebe091244d69b16187e3903ba5ef5be2c5ca132ee52bca4040fd3d
grub2-efi-2.02-0.29.el7.x86_64.rpm
File outdated by:  RHBA-2016:2336
    MD5: 630618de4e6a177db5d67ad9a9f0b56b
SHA-256: a2ae5a4ee0738578f0cfb7efd70692314766baa4d76cd65c762e3b996d716710
grub2-efi-modules-2.02-0.29.el7.x86_64.rpm
File outdated by:  RHBA-2016:0003
    MD5: abfdccd26500a165024bf3e2b676e5ab
SHA-256: 1790114dee473fe434036ddf3f54f61f79c2d0e2188ad2a63f84ce0891f3e722
grub2-tools-2.02-0.29.el7.x86_64.rpm
File outdated by:  RHBA-2016:2336
    MD5: 33d686e5a208b775178f08820d40cd4c
SHA-256: d701afcaa763b1364062b7aa8a004807954b8990025c29c2b9fb574e0312f76c
 
Red Hat Enterprise Linux Server (v. 7)

SRPMS:
grub2-2.02-0.29.el7.src.rpm
File outdated by:  RHBA-2016:2336
    MD5: 6f1b37e564836fce02a731be50d95d9b
SHA-256: 1138d2be2fc12f399d16726f03fc7a09390ff61adca72b476b701af847d8755b
 
PPC:
grub2-2.02-0.29.el7.ppc64.rpm
File outdated by:  RHBA-2016:2336
    MD5: bad10dd12cebd2e5709f6b89f107b37b
SHA-256: c43902cca8d963bbd5e971b651fbfb58946e0a28b32654e5f596c5d68bce17cf
grub2-debuginfo-2.02-0.29.el7.ppc64.rpm
File outdated by:  RHBA-2016:2336
    MD5: 61d374c54c626d3e65f1a798b4a8efc5
SHA-256: eda1c3ac63da878db6270143323d3902b302762378917053740a603c43e826eb
grub2-tools-2.02-0.29.el7.ppc64.rpm
File outdated by:  RHBA-2016:2336
    MD5: 2b3a8cceb5093769dfb3eb8b04566d7a
SHA-256: fa25c79f045423b99e4f6572689bba436254b3c1bb3646d8befe9aa18673fe6f
 
PPC64LE:
grub2-2.02-0.29.el7.ppc64le.rpm
File outdated by:  RHBA-2016:2336
    MD5: 6b5749f6d59df618741e3ca503f2ae48
SHA-256: fbd67f9bcb4b5b086d4ca82ba6efc2ae4b5c497c97d7e7a024db163f01e9ff4d
grub2-debuginfo-2.02-0.29.el7.ppc64le.rpm
File outdated by:  RHBA-2016:2336
    MD5: 00485ecffe980c37a8331965dbe5868d
SHA-256: 916b180a876f738ef4772e46ce860509f4c613b345d81e729b1f52338a968698
grub2-tools-2.02-0.29.el7.ppc64le.rpm
File outdated by:  RHBA-2016:2336
    MD5: 4ebb8e3136f1dc6305db4e8b689869c5
SHA-256: 519b81e100a155e5111ec3abe1d0b49e9443e21e47bc32d659dc7fca66e6f306
 
x86_64:
grub2-2.02-0.29.el7.x86_64.rpm
File outdated by:  RHBA-2016:2336
    MD5: b8232630ee1cdc45edc328b02b8c867b
SHA-256: 20910d54ed0d7956d3948235326a65bff4a510bcfbaee3ec120d17b1b904afe8
grub2-debuginfo-2.02-0.29.el7.x86_64.rpm
File outdated by:  RHBA-2016:0003
    MD5: 22e39a73491231dcd762eb35bed4f4be
SHA-256: 08ae48b99cebe091244d69b16187e3903ba5ef5be2c5ca132ee52bca4040fd3d
grub2-efi-2.02-0.29.el7.x86_64.rpm
File outdated by:  RHBA-2016:2336
    MD5: 630618de4e6a177db5d67ad9a9f0b56b
SHA-256: a2ae5a4ee0738578f0cfb7efd70692314766baa4d76cd65c762e3b996d716710
grub2-efi-modules-2.02-0.29.el7.x86_64.rpm
File outdated by:  RHBA-2016:0003
    MD5: abfdccd26500a165024bf3e2b676e5ab
SHA-256: 1790114dee473fe434036ddf3f54f61f79c2d0e2188ad2a63f84ce0891f3e722
grub2-tools-2.02-0.29.el7.x86_64.rpm
File outdated by:  RHBA-2016:2336
    MD5: 33d686e5a208b775178f08820d40cd4c
SHA-256: d701afcaa763b1364062b7aa8a004807954b8990025c29c2b9fb574e0312f76c
 
Red Hat Enterprise Linux Workstation (v. 7)

SRPMS:
grub2-2.02-0.29.el7.src.rpm
File outdated by:  RHBA-2016:2336
    MD5: 6f1b37e564836fce02a731be50d95d9b
SHA-256: 1138d2be2fc12f399d16726f03fc7a09390ff61adca72b476b701af847d8755b
 
x86_64:
grub2-2.02-0.29.el7.x86_64.rpm
File outdated by:  RHBA-2016:2336
    MD5: b8232630ee1cdc45edc328b02b8c867b
SHA-256: 20910d54ed0d7956d3948235326a65bff4a510bcfbaee3ec120d17b1b904afe8
grub2-debuginfo-2.02-0.29.el7.x86_64.rpm
File outdated by:  RHBA-2016:0003
    MD5: 22e39a73491231dcd762eb35bed4f4be
SHA-256: 08ae48b99cebe091244d69b16187e3903ba5ef5be2c5ca132ee52bca4040fd3d
grub2-efi-2.02-0.29.el7.x86_64.rpm
File outdated by:  RHBA-2016:2336
    MD5: 630618de4e6a177db5d67ad9a9f0b56b
SHA-256: a2ae5a4ee0738578f0cfb7efd70692314766baa4d76cd65c762e3b996d716710
grub2-efi-modules-2.02-0.29.el7.x86_64.rpm
File outdated by:  RHBA-2016:0003
    MD5: abfdccd26500a165024bf3e2b676e5ab
SHA-256: 1790114dee473fe434036ddf3f54f61f79c2d0e2188ad2a63f84ce0891f3e722
grub2-tools-2.02-0.29.el7.x86_64.rpm
File outdated by:  RHBA-2016:2336
    MD5: 33d686e5a208b775178f08820d40cd4c
SHA-256: d701afcaa763b1364062b7aa8a004807954b8990025c29c2b9fb574e0312f76c
 
(The unlinked packages above are only available from the Red Hat Network)

Bugs fixed (see bugzilla for more information)

1001279 - grub2 can't boot new xfs CRC-capable disk format
1124074 - grub2-mkconfig wrong sorting
1125404 - [RHEL 7] grub2 improperly escapes spaces in kernel parameters
1148650 - no docs explaining what config path GRUB expects when netbooting
1177003 - yum reinstall kernel causes duplicate entry in grub menu
1211101 - grub2 fw_path variable is incorrect for x86 EFI network boot: too many path components stripped
1264103 - CVE-2015-5281 grub2: modules built in on EFI builds that allow loading arbitrary code, circumventing secure boot


References



These packages are GPG signed by Red Hat for security. Our key and details on how to verify the signature are available from:
https://www.redhat.com/security/team/key/#package

The Red Hat security contact is secalert@redhat.com. More contact details at http://www.redhat.com/security/team/contact/