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RHSA-2010:0126: kvm security and bug fix update

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RHSA-2010:0126: kvm security and bug fix update



KVM (Kernel-based Virtual Machine) is a full virtualization solution forLinux on AMD64 and Intel 64 systems. KVM is a Linux kernel module built forthe standard Red Hat Enterprise Linux kernel.A flaw was found in the way the x86 emulator loaded segment selectors (usedfor memory segmentation and protection) into segment registers. In someguest system configurations, an unprivileged guest user could leverage thisflaw to crash the guest or possibly escalate their privileges within theguest. (CVE-2010-0419)The x86 emulator implementation was missing a check for the CurrentPrivilege Level (CPL) while accessing debug registers. An unprivilegeduser in a guest could leverage this flaw to crash the guest.(CVE-2009-3722)This update also fixes the following bugs:With Red Hat Enterprise Virtualization, the virtio_blk_dma_restart_bh()function was previously used to handle write errors; however, a bug fixprovided by the RHSA-2009:1659 update meant that read errors would alsohave to be handled by this function. The function was not updated for this,causing read errors to be resubmitted as writes. This caused guest imagecorruption in some cases.Additionally, the return values of the bdrv_aio_write() and bdrv_aio_read()functions were ignored. If an immediate failure occurred in one of thesefunctions, errors would be missed and the guest could hang or readcorrupted data. (BZ#562776)All KVM users should upgrade to these updated packages, which containbackported patches to resolve these issues. Note: The procedure in theSolution section must be performed before this update will take effect.


  • redhat-upgrade-kmod-kvm
  • redhat-upgrade-kvm
  • redhat-upgrade-kvm-qemu-img
  • redhat-upgrade-kvm-tools

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