USN-2759-1: Linux kernel vulnerabilities

1 October 2015

linux vulnerabilities

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

  • Ubuntu 12.04 LTS

Summary

Several security issues were fixed in the kernel.

Software Description

  • linux - Linux kernel

Details

It was discovered that an integer overflow error existed in the SCSI generic (sg) driver in the Linux kernel. A local attacker with write permission to a SCSI generic device could use this to cause a denial of service (system crash) or potentially escalate their privileges. (CVE-2015-5707)

Marc-André Lureau discovered that the vhost driver did not properly release the userspace provided log file descriptor. A privileged attacker could use this to cause a denial of service (resource exhaustion). (CVE-2015-6252)

It was discovered that the Linux kernel’s perf subsystem did not bound callchain backtraces on PowerPC 64. A local attacker could use this to cause a denial of service. (CVE-2015-6526)

Update instructions

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

Ubuntu 12.04 LTS
linux-image-3.2.0-91-generic - 3.2.0-91.129
linux-image-3.2.0-91-generic-pae - 3.2.0-91.129
linux-image-3.2.0-91-highbank - 3.2.0-91.129
linux-image-3.2.0-91-omap - 3.2.0-91.129
linux-image-3.2.0-91-powerpc-smp - 3.2.0-91.129
linux-image-3.2.0-91-powerpc64-smp - 3.2.0-91.129
linux-image-3.2.0-91-virtual - 3.2.0-91.129

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