Updated kernel packages that fix several security issues are now available for CentOS Linux 4. This update has been rated as having important security impact by the Red Hat Security Response Team.
The Linux kernel handles the basic functions of the operating system. This advisory includes fixes for several security issues: iSEC Security Research discovered multiple vulnerabilities in the IGMP functionality. These flaws could allow a local user to cause a denial of service (crash) or potentially gain privileges. Where multicast applications are being used on a system, these flaws may also allow remote users to cause a denial of service. The Common Vulnerabilities and Exposures project (cve.mitre.org) has assigned the name CAN-2004-1137 to this issue. iSEC Security Research discovered a flaw in the page fault handler code that could lead to local users gaining elevated (root) privileges on multiprocessor machines. (CAN-2005-0001) iSEC Security Research discovered a VMA handling flaw in the uselib(2) system call of the Linux kernel. A local user could make use of this flaw to gain elevated (root) privileges. (CAN-2004-1235) A flaw affecting the OUTS instruction on the AMD64 and Intel EM64T architecture was discovered. A local user could use this flaw to write to privileged IO ports. (CAN-2005-0204) The Direct Rendering Manager (DRM) driver in Linux kernel 2.6 does not properly check the DMA lock, which could allow remote attackers or local users to cause a denial of service (X Server crash) or possibly modify the video output. (CAN-2004-1056) OGAWA Hirofumi discovered incorrect tables sizes being used in the filesystem Native Language Support ASCII translation table. This could lead to a denial of service (system crash). (CAN-2005-0177) Michael Kerrisk discovered a flaw in the 2.6.9 kernel which allows users to unlock arbitrary shared memory segments. This flaw could lead to applications not behaving as expected. (CAN-2005-0176) Improvements in the POSIX signal and tty standards compliance exposed a race condition. This flaw can be triggered accidentally by threaded applications or deliberately by a malicious user and can result in a denial of service (crash) or in occasional cases give access to a small random chunk of kernel memory. (CAN-2005-0178) The PaX team discovered a flaw in mlockall introduced in the 2.6.9 kernel. An unprivileged user could use this flaw to cause a denial of service (CPU and memory consumption or crash). (CAN-2005-0179) Brad Spengler discovered multiple flaws in sg_scsi_ioctl in the 2.6 kernel. An unprivileged user may be able to use this flaw to cause a denial of service (crash) or possibly other actions. (CAN-2005-0180) Kirill Korotaev discovered a missing access check regression in the CentOS Enterprise Linux 4 kernel 4GB/4GB split patch. On systems using the hugemem kernel, a local unprivileged user could use this flaw to cause a denial of service (crash). (CAN-2005-0090) A flaw in the CentOS Linux 4 kernel 4GB/4GB split patch can allow syscalls to read and write arbitrary kernel memory. On systems using the hugemem kernel, a local unprivileged user could use this flaw to gain privileges. (CAN-2005-0091) An additional flaw in the CentOS Linux 4 kernel 4GB/4GB split patch was discovered. On x86 systems using the hugemem kernel, a local unprivileged user may be able to use this flaw to cause a denial of service (crash). (CAN-2005-0092) All CentOS Linux 4 users are advised to upgrade their kernels to the packages associated with their machine architectures and configurations as listed in this erratum.