USN-3392-2: Linux kernel (Xenial HWE) regression

Ubuntu Security Notice USN-3392-2

16th August, 2017

linux-lts-xenial regression

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

  • Ubuntu 14.04 LTS

Summary

USN-3378-2 introduced a regression the Linux Hardware Enablement kernel.

Software description

  • linux-lts-xenial - Linux hardware enablement kernel from Xenial for Trusty

Details

USN-3392-1 fixed a regression in the Linux kernel for Ubuntu 16.04 LTS.
This update provides the corresponding updates for the Linux Hardware
Enablement (HWE) kernel from Ubuntu 16.04 LTS for Ubuntu 14.04 LTS.

USN-3378-2 fixed vulnerabilities in the Linux Hardware Enablement
kernel. Unfortunately, a regression was introduced that prevented
conntrack from working correctly in some situations. This update
fixes the problem.

We apologize for the inconvenience.

Original advisory details:

Fan Wu and Shixiong Zhao discovered a race condition between inotify events
and vfs rename operations in the Linux kernel. An unprivileged local
attacker could use this to cause a denial of service (system crash) or
execute arbitrary code. (CVE-2017-7533)

It was discovered that the Linux kernel did not properly restrict
RLIMIT_STACK size. A local attacker could use this in conjunction with
another vulnerability to possibly execute arbitrary code.
(CVE-2017-1000365)

李强 discovered that the Virtio GPU driver in the Linux kernel did not
properly free memory in some situations. A local attacker could use this to
cause a denial of service (memory consumption). (CVE-2017-10810)

石磊 discovered that the RxRPC Kerberos 5 ticket handling code in the
Linux kernel did not properly verify metadata. A remote attacker could use
this to cause a denial of service (system crash) or possibly execute
arbitrary code. (CVE-2017-7482)

Update instructions

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

Ubuntu 14.04 LTS:
linux-image-powerpc-smp-lts-xenial 4.4.0.92.76
linux-image-generic-lpae-lts-xenial 4.4.0.92.76
linux-image-4.4.0-92-powerpc-e500mc 4.4.0-92.115~14.04.1
linux-image-4.4.0-92-powerpc64-emb 4.4.0-92.115~14.04.1
linux-image-4.4.0-92-powerpc-smp 4.4.0-92.115~14.04.1
linux-image-4.4.0-92-lowlatency 4.4.0-92.115~14.04.1
linux-image-lowlatency-lts-xenial 4.4.0.92.76
linux-image-generic-lts-xenial 4.4.0.92.76
linux-image-4.4.0-92-generic-lpae 4.4.0-92.115~14.04.1
linux-image-powerpc64-smp-lts-xenial 4.4.0.92.76
linux-image-powerpc64-emb-lts-xenial 4.4.0.92.76
linux-image-4.4.0-92-powerpc64-smp 4.4.0-92.115~14.04.1
linux-image-powerpc-e500mc-lts-xenial 4.4.0.92.76
linux-image-4.4.0-92-generic 4.4.0-92.115~14.04.1

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.
Unless you manually uninstalled the standard kernel metapackages
(e.g. linux-generic, linux-generic-lts-RELEASE, linux-virtual,
linux-powerpc), a standard system upgrade will automatically perform
this as well.

References

https://bugs.launchpad.net/bugs/1709032, https://usn.ubuntu.com/usn/usn-3378-2