USN-3821-1: Linux kernel vulnerabilities

14 November 2018

Several security issues were fixed in the Linux kernel.

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Details

Wen Xu discovered that the ext4 filesystem implementation in the Linux
kernel did not properly ensure that xattr information remained in inode
bodies. An attacker could use this to construct a malicious ext4 image
that, when mounted, could cause a denial of service (system crash).
(CVE-2018-10880)

It was discovered that the alarmtimer implementation in the Linux kernel
contained an integer overflow vulnerability. A local attacker could use
this to cause a denial of service. (CVE-2018-13053)

Wen Xu discovered that the f2fs filesystem implementation in the Linux
kernel did not properly validate metadata. An attacker could use this to
construct a malicious f2fs image that, when mounted, could cause a denial
of service (system crash). (CVE-2018-13096)

Wen Xu and Po-Ning Tseng discovered that the btrfs filesystem
implementation in the Linux kernel did not properly handle relocations in
some situations. An attacker could use this to construct a malicious btrfs
image that, when mounted, could cause a denial of service (system crash).
(CVE-2018-14609)

Wen Xu discovered that the HFS+ filesystem implementation in the Linux
kernel did not properly handle malformed catalog data in some situations.
An attacker could use this to construct a malicious HFS+ image that, when
mounted, could cause a denial of service (system crash). (CVE-2018-14617)

Jann Horn discovered that the procfs file system implementation in the
Linux kernel did not properly restrict the ability to inspect the kernel
stack of an arbitrary task. A local attacker could use this to expose
sensitive information. (CVE-2018-17972)

It was discovered that the KVM implementation in the Linux kernel on ARM
64bit processors did not properly handle some ioctls. An attacker with the
privilege to create KVM-based virtual machines could use this to cause a
denial of service (host system crash) or execute arbitrary code in the
host. (CVE-2018-18021)

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Update instructions

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

Ubuntu 16.04

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

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