CVE-2022-50772

A memory leak vulnerability exists in the netdevsim driver's nsim_bus_dev_new() function within the Linux kernel. When device_register() fails, the device name allocated via dev_set_name() is not freed, leading to a leak of the name string. This issue is evidenced by the backtrace showing allocation through kvasprintf and dev_set_name without subsequent cleanup on the error path.

The leak can be triggered by writing to the sysfs interface to create a new netdevsim device (e.g., via new_device_store). If the device registration fails due to resource constraints or other errors, the allocated name memory remains unreleased. Exploitation requires local access to the sysfs filesystem, typically with root privileges.

An attacker with local access can repeatedly trigger the memory leak, gradually exhausting kernel memory and causing a denial of service (DoS). The vulnerability does not lead to privilege escalation or data corruption.

The issue was resolved in Linux kernel commit 77579e406529 [1], which ensures proper cleanup of the device name on the failure path. Users should apply the corresponding kernel update or backport the fix to affected stable trees.