CVE-2021-46945

Technical Description

In the Linux kernel, the following vulnerability has been resolved:

ext4: always panic when errors=panic is specified

Before commit 014c9caa29d3 ("ext4: make ext4_abort() use

__ext4_error()"), the following series of commands would trigger a

panic:

1. mount /dev/sda -o ro,errors=panic test

2. mount /dev/sda -o remount,abort test

After commit 014c9caa29d3, remounting a file system using the test

mount option "abort" will no longer trigger a panic. This commit will

restore the behaviour immediately before commit 014c9caa29d3.

(However, note that the Linux kernel's behavior has not been

consistent; some previous kernel versions, including 5.4 and 4.19

similarly did not panic after using the mount option "abort".)

This also makes a change to long-standing behaviour; namely, the

following series commands will now cause a panic, when previously it

did not:

1. mount /dev/sda -o ro,errors=panic test

2. echo test > /sys/fs/ext4/sda/trigger_fs_error

However, this makes ext4's behaviour m

Remediation

Check the references section for vendor advisories and patches from linux. Update linux_kernel to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

Affected Products

References