ext4: kernel panic when writing data to the last block of sparse file
CVE: CVE-2011-2695
Component: kernel
Severity: Moderate
Release date: 2011-06-03T00:00:00+00:00

Multiple off-by-one errors in the ext4 subsystem in the Linux kernel before 3.0-rc5 allow local users to cause a denial of service (BUG_ON and system crash) by accessing a sparse file in extent format with a write operation involving a block number corresponding to the largest possible 32-bit unsigned integer.

Statement: This has been addressed in Red Hat Enterprise Linux 5, 6 and Red Hat Enterprise MRG via https://rhn.redhat.com/errata/RHSA-2011-1386.html,  https://rhn.redhat.com/errata/RHSA-2011-1189.html, and https://rhn.redhat.com/errata/RHSA-2011-1253.html. This issue did not affect the versions of Linux kernel as shipped with Red Hat Enterprise Linux 4 as it did not include support for EXT4 filesystem.

Remediation:
This update also fixes several bugs and adds one enhancement.
Documentation for these changes will be available shortly from the
Technical Notes document linked to in the References section.

Users should upgrade to these updated packages, which contain
backported patches to correct these issues, and fix the bugs and add
the enhancement noted in the Technical Notes. The system must be
rebooted for this update to take effect.

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

To install kernel packages manually, use "rpm -ivh [package]". Do not
use "rpm -Uvh" as that will remove the running kernel binaries from
your system. You may use "rpm -e" to remove old kernels after
determining that the new kernel functions properly on your system.
Refer to the Technical Notes, available shortly from the link in the
References, for bug fix and enhancement details.

Users should upgrade to these updated packages, which contain
backported patches to correct these issues, and fix the bugs and add
the enhancements noted in the Technical Notes. The system must be
rebooted for this update to take effect.

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

To install kernel packages manually, use "rpm -ivh [package]". Do not
use "rpm -Uvh" as that will remove the running kernel binaries from
your system. You may use "rpm -e" to remove old kernels after
determining that the new kernel functions properly on your system.
This update also fixes various bugs. Documentation for these bug fixes
will be available shortly from the Technical Notes document linked to
in the References section.

Users should upgrade to these updated packages, which correct these
issues, and fix the bugs noted in the Technical Notes. The system
must be rebooted for this update to take effect.

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

To install kernel packages manually, use "rpm -ivh [package]". Do not
use "rpm -Uvh" as that will remove the running kernel binaries from
your system. You may use "rpm -e" to remove old kernels after
determining that the new kernel functions properly on your system.