keys: NULL pointer deref in the user-defined key type
CVE: CVE-2011-4110
Component: kernel
CWE: CWE-476
Severity: Moderate
Release date: 2011-11-15T00:00:00+00:00

The user_update function in security/keys/user_defined.c in the Linux kernel 2.6 allows local users to cause a denial of service (NULL pointer dereference and kernel oops) via vectors related to a user-defined key and "updating a negative key into a fully instantiated key."

Statement: This issue affects the Linux kernel as shipped with Red Hat Enterprise Linux 4,
5, 6, and Red Hat Enterprise MRG. This has been addressed in Red Hat Enterprise Linux 5, 6 and Red Hat Enterprise MRG via https://rhn.redhat.com/errata/RHSA-2011-1479.html, https://rhn.redhat.com/errata/RHSA-2011-1530.html, and https://rhn.redhat.com/errata/RHSA-2012-0010.html. Red Hat Enterprise Linux 4 is now in Production 3 of the maintenance life-cycle, https://access.redhat.com/support/policy/updates/errata/, therefore the fix for this issue is not currently planned to be included in the future updates.

Remediation:
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.
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.
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.
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.
Users should upgrade to these updated packages, which correct these
issues. 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/knowledge/articles/11258

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.