USN-5209-1: Linux kernel vulnerabilities

Publication date

6 January 2022

Overview

Several security issues were fixed in the Linux kernel.


Packages

Details

Nadav Amit discovered that the hugetlb implementation in the Linux kernel
did not perform TLB flushes under certain conditions. A local attacker
could use this to leak or alter data from other processes that use huge
pages. (CVE-2021-4002)

It was discovered that a race condition existed in the timer implementation
in the Linux kernel. A privileged attacker could use this cause a denial of
service. (CVE-2021-20317)

It was discovered that a race condition existed in the overlay file system
implementation in the Linux kernel. A local attacker could use this to
cause a denial of service (system crash). (CVE-2021-20321)

It was discovered that the NFC subsystem in the Linux kernel contained a
use-after-free vulnerability in its NFC Controller Interface (NCI)
implementation. A local attacker could possibly use this...

Nadav Amit discovered that the hugetlb implementation in the Linux kernel
did not perform TLB flushes under certain conditions. A local attacker
could use this to leak or alter data from other processes that use huge
pages. (CVE-2021-4002)

It was discovered that a race condition existed in the timer implementation
in the Linux kernel. A privileged attacker could use this cause a denial of
service. (CVE-2021-20317)

It was discovered that a race condition existed in the overlay file system
implementation in the Linux kernel. A local attacker could use this to
cause a denial of service (system crash). (CVE-2021-20321)

It was discovered that the NFC subsystem in the Linux kernel contained a
use-after-free vulnerability in its NFC Controller Interface (NCI)
implementation. A local attacker could possibly use this to cause a denial
of service (system crash) or execute arbitrary code. (CVE-2021-3760)

It was discovered that an integer overflow could be triggered in the eBPF
implementation in the Linux kernel when preallocating objects for stack
maps. A privileged local attacker could use this to cause a denial of
service or possibly execute arbitrary code. (CVE-2021-41864)

It was discovered that the ISDN CAPI implementation in the Linux kernel
contained a race condition in certain situations that could trigger an
array out-of-bounds bug. A privileged local attacker could possibly use
this to cause a denial of service or execute arbitrary code.
(CVE-2021-43389)


Update instructions

After a standard system update you need to reboot your computer to make all the necessary changes.

Learn more about how to get the fixes.

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.

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

Ubuntu Release Package Version
18.04 bionic linux-image-4.15.0-1033-dell300x –  4.15.0-1033.38
linux-image-4.15.0-1085-oracle –  4.15.0-1085.93
linux-image-4.15.0-1101-raspi2 –  4.15.0-1101.108
linux-image-4.15.0-1105-kvm –  4.15.0-1105.107
linux-image-4.15.0-1114-gcp –  4.15.0-1114.128
linux-image-4.15.0-1118-aws –  4.15.0-1118.125
linux-image-4.15.0-1118-snapdragon –  4.15.0-1118.127
linux-image-4.15.0-1129-azure –  4.15.0-1129.142
linux-image-4.15.0-166-generic –  4.15.0-166.174
linux-image-4.15.0-166-generic-lpae –  4.15.0-166.174
linux-image-4.15.0-166-lowlatency –  4.15.0-166.174
linux-image-aws-lts-18.04 –  4.15.0.1118.121
linux-image-azure-lts-18.04 –  4.15.0.1129.102
linux-image-dell300x –  4.15.0.1033.35
linux-image-gcp-lts-18.04 –  4.15.0.1114.133
linux-image-generic –  4.15.0.166.155
linux-image-generic-lpae –  4.15.0.166.155
linux-image-kvm –  4.15.0.1105.101
linux-image-lowlatency –  4.15.0.166.155
linux-image-oracle-lts-18.04 –  4.15.0.1085.95
linux-image-raspi2 –  4.15.0.1101.99
linux-image-snapdragon –  4.15.0.1118.121
linux-image-virtual –  4.15.0.166.155
16.04 xenial linux-image-4.15.0-1085-oracle –  4.15.0-1085.93~16.04.1  
linux-image-4.15.0-1114-gcp –  4.15.0-1114.128~16.04.1  
linux-image-4.15.0-1118-aws –  4.15.0-1118.125~16.04.1  
linux-image-4.15.0-1129-azure –  4.15.0-1129.142~16.04.1  
linux-image-4.15.0-166-generic –  4.15.0-166.174~16.04.1  
linux-image-4.15.0-166-lowlatency –  4.15.0-166.174~16.04.1  
linux-image-aws-hwe –  4.15.0.1118.108  
linux-image-azure –  4.15.0.1129.120  
linux-image-gcp –  4.15.0.1114.115  
linux-image-generic-hwe-16.04 –  4.15.0.166.158  
linux-image-gke –  4.15.0.1114.115  
linux-image-lowlatency-hwe-16.04 –  4.15.0.166.158  
linux-image-oem –  4.15.0.166.158  
linux-image-oracle –  4.15.0.1085.73  
linux-image-virtual-hwe-16.04 –  4.15.0.166.158  
14.04 trusty linux-image-4.15.0-1129-azure –  4.15.0-1129.142~14.04.1  
linux-image-azure –  4.15.0.1129.102  

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