USN-4658-2: Linux kernel regression

13 December 2020

USN-4658-1 introduced a regression in the Linux kernel.

Reduce your security exposure

Ubuntu Pro provides ten-year security coverage to 25,000+ packages in Main and Universe repositories, and it is free for up to five machines.

Learn more about Ubuntu Pro

Releases

Packages

Details

USN-4658-1 fixed vulnerabilities in the Linux kernel. Unfortunately,
that update introduced a regression in the software raid10 driver
when used with fstrim that could lead to data corruption. This update
fixes the problem.

Original advisory details:

It was discovered that a race condition existed in the binder IPC
implementation in the Linux kernel, leading to a use-after-free
vulnerability. A local attacker could use this to cause a denial of service
(system crash) or possibly execute arbitrary code. (CVE-2020-0423)

Daniele Antonioli, Nils Ole Tippenhauer, and Kasper Rasmussen discovered
that legacy pairing and secure-connections pairing authentication in the
Bluetooth protocol could allow an unauthenticated user to complete
authentication without pairing credentials via adjacent access. A
physically proximate attacker could use this to impersonate a previously
paired Bluetooth device. (CVE-2020-10135)

It was discovered that a race condition existed in the perf subsystem of
the Linux kernel, leading to a use-after-free vulnerability. An attacker
with access to the perf subsystem could use this to cause a denial of
service (system crash) or possibly execute arbitrary code. (CVE-2020-14351)

It was discovered that the frame buffer implementation in the Linux kernel
did not properly handle some edge cases in software scrollback. A local
attacker could use this to cause a denial of service (system crash) or
possibly execute arbitrary code. (CVE-2020-14390)

It was discovered that the netfilter connection tracker for netlink in the
Linux kernel did not properly perform bounds checking in some situations. A
local attacker could use this to cause a denial of service (system crash).
(CVE-2020-25211)

It was discovered that the Rados block device (rbd) driver in the Linux
kernel did not properly perform privilege checks for access to rbd devices
in some situations. A local attacker could use this to map or unmap rbd
block devices. (CVE-2020-25284)

It was discovered that the HDLC PPP implementation in the Linux kernel did
not properly validate input in some situations. A local attacker could use
this to cause a denial of service (system crash) or possibly execute
arbitrary code. (CVE-2020-25643)

It was discovered that the GENEVE tunnel implementation in the Linux kernel
when combined with IPSec did not properly select IP routes in some
situations. An attacker could use this to expose sensitive information
(unencrypted network traffic). (CVE-2020-25645)

Keyu Man discovered that the ICMP global rate limiter in the Linux kernel
could be used to assist in scanning open UDP ports. A remote attacker could
use to facilitate attacks on UDP based services that depend on source port
randomization. (CVE-2020-25705)

It was discovered that the framebuffer implementation in the Linux kernel
did not properly perform range checks in certain situations. A local
attacker could use this to expose sensitive information (kernel memory).
(CVE-2020-28915)

It was discovered that Power 9 processors could be coerced to expose
information from the L1 cache in certain situations. A local attacker could
use this to expose sensitive information. (CVE-2020-4788)

Reduce your security exposure

Ubuntu Pro provides ten-year security coverage to 25,000+ packages in Main and Universe repositories, and it is free for up to five machines.

Learn more about Ubuntu Pro

Update instructions

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

Ubuntu 20.04
Ubuntu 18.04

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

Join the discussion

Need help with your security needs?

Ubuntu Pro provides up to ten-year security coverage for over 23,000 open-source packages within the Ubuntu Main and Universe repositories.

Talk to an expert to find out what would work best for you

Further reading