USN-2420-1: Linux kernel vulnerabilities

25 November 2014

linux vulnerabilities

A security issue affects these releases of Ubuntu and its derivatives:

  • Ubuntu 14.04 LTS

Summary

Several security issues were fixed in the kernel.

Software Description

  • linux - Linux kernel

Details

A flaw was discovered in how the Linux kernel’s KVM (Kernel Virtual Machine) subsystem handles the CR4 control register at VM entry on Intel processors. A local host OS user can exploit this to cause a denial of service (kill arbitrary processes, or system disruption) by leveraging /dev/kvm access. (CVE-2014-3690)

Don Bailey discovered a flaw in the LZO decompress algorithm used by the Linux kernel. An attacker could exploit this flaw to cause a denial of service (memory corruption or OOPS). (CVE-2014-4608)

Andy Lutomirski discovered a flaw in how the Linux kernel handles pivot_root when used with a chroot directory. A local user could exploit this flaw to cause a denial of service (mount-tree loop). (CVE-2014-7970)

Andy Lutomirski discovered that the Linux kernel was not checking the CAP_SYS_ADMIN when remounting filesystems to read-only. A local user could exploit this flaw to cause a denial of service (loss of writability). (CVE-2014-7975)

Update instructions

The problem can be corrected by updating your system to the following package versions:

Ubuntu 14.04 LTS
linux-image-3.13.0-40-generic - 3.13.0-40.69
linux-image-3.13.0-40-generic-lpae - 3.13.0-40.69
linux-image-3.13.0-40-lowlatency - 3.13.0-40.69
linux-image-3.13.0-40-powerpc-e500 - 3.13.0-40.69
linux-image-3.13.0-40-powerpc-e500mc - 3.13.0-40.69
linux-image-3.13.0-40-powerpc-smp - 3.13.0-40.69
linux-image-3.13.0-40-powerpc64-emb - 3.13.0-40.69
linux-image-3.13.0-40-powerpc64-smp - 3.13.0-40.69

To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.

After a standard system update you need to reboot your computer to make all the necessary changes.

ATTENTION: Due to an unavoidable ABI change the kernel updates have been given a new version number, which requires you to recompile and reinstall all third party kernel modules you might have installed. If you use linux-restricted-modules, you have to update that package as well to get modules which work with the new kernel version. Unless you manually uninstalled the standard kernel metapackages (e.g. linux-generic, linux-server, linux-powerpc), a standard system upgrade will automatically perform this as well.

References