[USN-4915-1] Linux kernel (OEM) vulnerabilities

========================================================================== Ubuntu Security Notice USN-4915-1 April 15, 2021
linux-oem-5.6 vulnerabilities ==========================================================================
A security issue affects these releases of Ubuntu and its derivatives:
– Ubuntu 20.04 LTS
Several security issues were fixed in the Linux kernel.
Software Description: – linux-oem-5.6: Linux kernel for OEM systems
It was discovered that the overlayfs implementation in the Linux kernel did not properly validate the application of file system capabilities with respect to user namespaces. A local attacker could use this to gain elevated privileges. (CVE-2021-3493)
Vincent Dehors discovered that the shiftfs file system in the Ubuntu Linux kernel did not properly handle faults in copy_from_user() when passing through ioctls to an underlying file system. A local attacker could use this to cause a denial of service (memory exhaustion) or execute arbitrary code. (CVE-2021-3492)
Update instructions:
The problem can be corrected by updating your system to the following package versions:
Ubuntu 20.04 LTS: linux-image-5.6.0-1054-oem 5.6.0-1054.58 linux-image-oem-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: ubuntu.com/security/notices/USN-4915-1 CVE-2021-3492, CVE-2021-3493
Package Information: launchpad.net/ubuntu/+source/linux-oem-5.6/5.6.0-1054.58