The kernel packages contain the Linux kernel, the core of any Linux operating system.
This update fixes the following security issues:
a race condition was found in the mac80211 implementation, a framework used for writing drivers for wireless devices. An attacker could trigger this flaw by sending a Delete Block ACK (DELBA) packet to a target system, resulting in a remote denial of service. Note: This issue only affected users on 802.11n networks, and that also use the iwlagn driver with Intel wireless hardware. (CVE-2009-4027, Important)
a flaw was found in the gfs2_lock() implementation. The GFS2 locking code could skip the lock operation for files that have the S_ISGID bit (set-group-ID on execution) in their mode set. A local, unprivileged user on a system that has a GFS2 file system mounted could use this flaw to cause a kernel panic. (CVE-2010-0727, Moderate)
a divide-by-zero flaw was found in the ext4 file system code. A local attacker could use this flaw to cause a denial of service by mounting a specially-crafted ext4 file system. (CVE-2009-4307, Low)
These updated packages also include several hundred bug fixes for and enhancements to the Linux kernel. Space precludes documenting each of these changes in this advisory and users are directed to the Red Hat Enterprise Linux 5.5 Release Notes for information on the most significant of these changes:
Also, for details concerning every bug fixed in and every enhancement added to the kernel for this release, refer to the kernel chapter in the Red Hat Enterprise Linux 5.5 Technical Notes:
All Red Hat Enterprise Linux 5 users are advised to install these updated packages, which address these vulnerabilities as well as fixing the bugs and adding the enhancements noted in the Red Hat Enterprise Linux 5.5 Release Notes and Technical Notes. The system must be rebooted for this update to take effect.