USN-2421-1: Linux kernel vulnerabilities

Ubuntu Security Notice USN-2421-1

24th November, 2014

linux vulnerabilities

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

  • Ubuntu 14.10

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 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 version:

Ubuntu 14.10:
linux-image-3.16.0-25-powerpc-smp

3.16.0-25.33
linux-image-3.16.0-25-powerpc-e500mc

3.16.0-25.33
linux-image-3.16.0-25-generic-lpae

3.16.0-25.33
linux-image-3.16.0-25-generic

3.16.0-25.33
linux-image-3.16.0-25-powerpc64-smp

3.16.0-25.33
linux-image-3.16.0-25-lowlatency

3.16.0-25.33
linux-image-3.16.0-25-powerpc64-emb

3.16.0-25.33

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

CVE-2014-3690,

CVE-2014-4608,

CVE-2014-7975