SciLinux: CVE-2009-4031 Moderate: kvm SL5.4 x86_64
Summary
Date: Thu, 10 Dec 2009 12:06:18 -0600Reply-To: Troy DawsonSender: Security Errata for Scientific Linux From: Troy Dawson Subject: Security ERRATA Moderate: kvm on SL5.4 x86_64Comments: To: "scientific-linux-errata@fnal.gov" Synopsis: Moderate: kvm security and bug fix updateIssue date: 2009-12-09CVE Names: CVE-2009-4031CVE-2009-4031 kernel: KVM: x86 emulator: limit instructions to 15 bytesOn x86 platforms, the do_insn_fetch() function did not limit the amount of instruction bytes fetched per instruction. Users in guest operating systems could leverage this flaw to cause large latencies on SMP hosts that could lead to a local denial of service on the host operating system. This update fixes this issue by imposing the architecturally-defined 15 byte length limit for instructions. (CVE-2009-4031)This update also fixes the following bugs:* performance problems occurred when using the qcow2 image format with the qemu-kvm -drive "cache=none" option (the default setting when not specified otherwise). This could cause guest operating system installations to take hours. With this update, performance patches have been backported so that using the qcow2 image format with the "cache=none" option no longer causes performance issues. (BZ#520693)* when using the virtual vm8086 mode, bugs in the emulated hardware taskswitching implementation may have, in some situations, caused older guest operating systems to malfunction. (BZ#532031)* Windows Server 2003 guests (32-bit) with more than 4GB of memory may have crashed during reboot when using the default qemu-kvm CPU settings.(BZ#532043)* with Scientific Linux Virtualization, guests continued to run afterencountering disk read errors. This could have led to their file systemsbecoming corrupted (but not the host's), notably in environments that use networked storage. With this update, the qemu-kvm -drive "werror=stop" option now applies not only to write errors but also to read errors: When using this option, guests will pause on disk read and write errors.By default, guests managed by Scientific Linux Virtualization use the"werror=stop" option. This option is not used by default for guests managed by libvirt. (BZ#537334, BZ#540406)* the para-virtualized block driver (virtio-blk) silently ignored readerrors when accessing disk images. With this update, the driver correctly signals the read error to the guest. (BZ#537334)SL 5.4 SRPMS:kvm-83-105.el5_4.13.src.rpm x86_64:kmod-kvm-83-105.el5_4.13.x86_64.rpmkvm-83-105.el5_4.13.x86_64.rpmkvm-qemu-img-83-105.el5_4.13.x86_64.rpmkvm-tools-83-105.el5_4.13.x86_64.rpm-Connie Sieh-Troy Dawson