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Ubuntu 15.10 USN-2843-1 Critical: KVM Denial Of Service Issues

ubuntu
Calendar Grey December 17, 2015
Scroller Ubuntu
Multiple security flaws resolved in the Linux kernel, affecting Ubuntu platforms. Make sure to implement the updates for optimal safety and performance.
Several security issues were fixed in the kernel.

Summary

Several security issues were fixed in the kernel.

Software Description:

- linux: Linux kernel

Details:

Jan Beulich discovered that the KVM svm hypervisor implementation in the

Linux kernel did not properly catch Debug exceptions on AMD processors. An

attacker in a guest virtual machine could use this to cause a denial of

service (system crash) in the host OS. (CVE-2015-8104)

郭永刚 discovered that the ppp implementation in the Linux kernel did

not ensure that certain slot numbers are valid. A local attacker with the

privilege to call ioctl() on /dev/ppp could cause a denial of service

(system crash). (CVE-2015-7799)

Dmitry Vyukov discovered that the Linux kernel's keyring handler attempted

to garbage collect incompletely instantiated keys. A local unprivileged

attacker could use this to cause a denial of service (system crash).

(CVE-2015-7872)

It was discovered that the virtual video osd test driver in the Linux

kernel did not properly initialize da...

Read the Full Advisory

Topics%20covered

Topics Covered

security advisory denial of service kernel ubuntu system crash information leakage KVM

Update Instructions

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

Ubuntu 15.10:
  linux-image-4.2.0-21-generic    4.2.0-21.25
  linux-image-4.2.0-21-generic-lpae  4.2.0-21.25
  linux-image-4.2.0-21-lowlatency  4.2.0-21.25
  linux-image-4.2.0-21-powerpc-e500mc  4.2.0-21.25
  linux-image-4.2.0-21-powerpc-smp  4.2.0-21.25
  linux-image-4.2.0-21-powerpc64-emb  4.2.0-21.25
  linux-image-4.2.0-21-powerpc64-smp  4.2.0-21.25

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

https://ubuntu.com/security/notices/USN-2843-1

CVE-2015-7799, CVE-2015-7872, CVE-2015-7884, CVE-2015-7885,

CVE-2015-8104

Severity
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Critical

December 17, 2015

Topics%20covered

Topics Covered

security advisory denial of service kernel ubuntu system crash information leakage KVM

Package Information

https://launchpad.net/ubuntu/+source/linux/4.2.0-21.25

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