USN-4391-1: Linux kernel vulnerabilities

11 June 2020

Several security issues were fixed in the Linux kernel.

Releases

Packages

  • linux - Linux kernel
  • linux-aws - Linux kernel for Amazon Web Services (AWS) systems
  • linux-kvm - Linux kernel for cloud environments
  • linux-lts-xenial - Linux hardware enablement kernel from Xenial for Trusty
  • linux-raspi2 - Linux kernel for Raspberry Pi (V7) systems
  • linux-snapdragon - Linux kernel for Qualcomm Snapdragon processors

Details

It was discovered that the ext4 file system implementation in the Linux
kernel did not properly handle setxattr operations in some situations. A
local attacker could use this to cause a denial of service (system crash)
or possibly execute arbitrary code. (CVE-2019-19319)

It was discovered that memory contents previously stored in
microarchitectural special registers after RDRAND, RDSEED, and SGX EGETKEY
read operations on Intel client and Xeon E3 processors may be briefly
exposed to processes on the same or different processor cores. A local
attacker could use this to expose sensitive information. (CVE-2020-0543)

Piotr Krysiuk discovered that race conditions existed in the file system
implementation in the Linux kernel. A local attacker could use this to
cause a denial of service (system crash). (CVE-2020-12114)

It was discovered that the USB susbsystem's scatter-gather implementation
in the Linux kernel did not properly take data references in some
situations, leading to a use-after-free. A physically proximate attacker
could use this to cause a denial of service (system crash) or possibly
execute arbitrary code. (CVE-2020-12464)

It was discovered that the DesignWare SPI controller driver in the Linux
kernel contained a race condition. A local attacker could possibly use this
to cause a denial of service (system crash). (CVE-2020-12769)

It was discovered that the exit signaling implementation in the Linux
kernel contained an integer overflow. A local attacker could use this to
cause a denial of service (arbitrary application crash). (CVE-2020-12826)

Xiumei Mu discovered that the IPSec implementation in the Linux kernel did
not properly encrypt IPv6 traffic in some situations. An attacker could use
this to expose sensitive information. (CVE-2020-1749)

Dmitry Vyukov discovered that the SELinux netlink security hook in the
Linux kernel did not validate messages in some situations. A privileged
attacker could use this to bypass SELinux netlink restrictions.
(CVE-2020-10751)

Update instructions

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

Ubuntu 16.04
Ubuntu 14.04

Please note that the mitigation for CVE-2020-0543 requires a processor
microcode update to be applied, either from your system manufacturer
or via the intel-microcode package. The kernel update for this issue
provides the ability to disable the mitigation and to report
vulnerability status.

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.