RHSA-2009:1243: Important: Red Hat Enterprise Linux 5.4 kernel security and bug fix update

The kernel packages contain the Linux kernel, the core of any Linuxoperating system.These updated packages fix the following security issues: it was discovered that, when executing a new process, the clearchildtid pointer in the Linux kernel is not cleared. If this pointer points to awritable portion of the memory of the new program, the kernel could corruptfour bytes of memory, possibly leading to a local denial of service orprivilege escalation. (CVE-2009-2848, Important) a flaw was found in the way the dosigaltstack() function in the Linux kernel copies the stackt structure to user-space. On 64-bit machines, thisflaw could lead to a four-byte information leak. (CVE-2009-2847, Moderate) a flaw was found in the ext4 file system code. A local attacker could use this flaw to cause a denial of service by performing a resize operation ona specially-crafted ext4 file system. (CVE-2009-0745, Low) multiple flaws were found in the ext4 file system code. A local attacker could use these flaws to cause a denial of service by mounting aspecially-crafted ext4 file system. (CVE-2009-0746, CVE-2009-0747,CVE-2009-0748, Low)These updated packages also include several hundred bug fixes for andenhancements to the Linux kernel. Space precludes documenting each of thesechanges in this advisory and users are directed to the Red Hat EnterpriseLinux 5.4 Release Notes for information on the most significant of thesechanges:http://www.redhat.com/docs/en-US/RedHatEnterpriseLinux/5.4/html/ReleaseNotes/ Also, for details concerning every bug fixed in and every enhancement addedto the kernel for this release, see the kernel chapter in the Red HatEnterprise Linux 5.4 Technical Notes:http://www.redhat.com/docs/en-US/RedHatEnterpriseLinux/5.4/html/TechnicalNotes/kernel.html All Red Hat Enterprise Linux 5 users are advised to install these updatedpackages, which address these vulnerabilities as well as fixing the bugsand adding the enhancements noted in the Red Hat Enterprise Linux 5.4Release Notes and Technical Notes. The system must be rebooted for thisupdate to take effect.