Ubuntu Security Notice 3170-1 - Dmitry Vyukov discovered that the KVM implementation in the Linux kernel did not properly initialize the Code Segment in certain error cases. A local attacker could use this to expose sensitive information. Andrey Konovalov discovered that signed integer overflows existed in the setsockopt system call when handling the SO_SNDBUFFORCE and SO_RCVBUFFORCE options. A local attacker with the CAP_NET_ADMIN capability could use this to cause a denial of service. Various other issues were also addressed.
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Ubuntu Security Notice USN-3170-1
January 11, 2017
linux vulnerabilities
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A security issue affects these releases of Ubuntu and its derivatives:
- Ubuntu 16.10
Summary:
Several security issues were fixed in the kernel.
Software Description:
- linux: Linux kernel
Details:
Dmitry Vyukov discovered that the KVM implementation in the Linux kernel
did not properly initialize the Code Segment (CS) in certain error cases. A
local attacker could use this to expose sensitive information (kernel
memory). (CVE-2016-9756)
Andrey Konovalov discovered that signed integer overflows existed in the
setsockopt() system call when handling the SO_SNDBUFFORCE and
SO_RCVBUFFORCE options. A local attacker with the CAP_NET_ADMIN capability
could use this to cause a denial of service (system crash or memory
corruption). (CVE-2016-9793)
Update instructions:
The problem can be corrected by updating your system to the following
package versions:
Ubuntu 16.10:
linux-image-4.8.0-34-generic 4.8.0-34.36
linux-image-4.8.0-34-generic-lpae 4.8.0-34.36
linux-image-4.8.0-34-lowlatency 4.8.0-34.36
linux-image-4.8.0-34-powerpc-e500mc 4.8.0-34.36
linux-image-4.8.0-34-powerpc-smp 4.8.0-34.36
linux-image-4.8.0-34-powerpc64-emb 4.8.0-34.36
linux-image-generic 4.8.0.34.43
linux-image-generic-lpae 4.8.0.34.43
linux-image-lowlatency 4.8.0.34.43
linux-image-powerpc-e500mc 4.8.0.34.43
linux-image-powerpc-smp 4.8.0.34.43
linux-image-powerpc64-emb 4.8.0.34.43
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:
http://www.ubuntu.com/usn/usn-3170-1
CVE-2016-9756, CVE-2016-9793
Package Information:
https://launchpad.net/ubuntu/+source/linux/4.8.0-34.36