USN-5265-1: Linux kernel vulnerabilities

3 February 2022

Several security issues were fixed in the Linux kernel.

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Details

Jeremy Cline discovered a use-after-free in the nouveau graphics driver of
the Linux kernel during device removal. A privileged or physically
proximate attacker could use this to cause a denial of service (system
crash). (CVE-2020-27820)

It was discovered that the Bluetooth subsystem in the Linux kernel
contained 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-2021-3640)

Likang Luo discovered that a race condition existed in the Bluetooth
subsystem of 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-2021-3752)

It was discovered that the SCTP protocol implementation in the Linux kernel
did not properly verify VTAGs in some situations. A remote attacker could
possibly use this to cause a denial of service (connection disassociation).
(CVE-2021-3772)

It was discovered that the eBPF implementation in the Linux kernel
contained a race condition around read-only maps. A privileged attacker
could use this to modify read-only maps. (CVE-2021-4001)

It was discovered that the NFS server implementation in the Linux kernel
contained an out-of-bounds write vulnerability. A local attacker could use
this to cause a denial of service (system crash) or possibly execute
arbitrary code. (CVE-2021-4090)

Felix Wilhelm discovered that the KVM implementation in the Linux kernel
did not properly handle exit events from AMD Secure Encrypted
Virtualization-Encrypted State (SEV-ES) guest VMs. An attacker in a guest
VM could use this to cause a denial of service (host kernel crash) or
possibly execute arbitrary code in the host kernel. (CVE-2021-4093)

Lin Ma discovered that the NFC Controller Interface (NCI) implementation in
the Linux kernel contained a race condition, 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-2021-4202)

It was discovered that the AMD Radeon GPU driver in the Linux kernel did
not properly validate writes in the debugfs file system. A privileged
attacker could use this to cause a denial of service (system crash) or
possibly execute arbitrary code. (CVE-2021-42327)

Luo Likang discovered that the FireDTV Firewire driver 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) or
possibly execute arbitrary code. (CVE-2021-42739)

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Update instructions

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

Ubuntu 21.10
Ubuntu 20.04

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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