Linux Kernel Btrfs NULL Pointer Dereference Vulnerability in Zoned Filesystems

A vulnerability in the Linux kernel's Btrfs file system has been addressed, which involved improper handling of zoned device information during the cloning process. When a Btrfs device was cloned, the associated zoned device information was not duplicated, leading to a NULL pointer dereference. This issue arose when the device's zone information was accessed, such as when activating a zone. The vulnerability was identified through a test case in the fstests suite.

Impact

Exploitation of this vulnerability could lead to a NULL pointer dereference, causing a kernel crash.

Reproduction

The vulnerability can be reproduced by cloning a Btrfs device in a zoned file system environment. This process will result in a NULL pointer dereference when the cloned device's zone information is accessed, such as during the activation of a zone.