Linux Kernel Netlink Subsystem Deadlock Vulnerability

A potential deadlock vulnerability has been identified in the Linux kernel's netlink subsystem, specifically in the 'netlink_set_err()' function. This issue arises from an interrupt-unlocked netlink table lock being accessed by another lock that is safe for soft interrupts, creating a risk of inverse lock ordering and a subsequent deadlock. The vulnerability affects several versions of the Linux kernel, including 6.4.0-rc6-syzkaller-00240-g4e9f0ec38852.

Impact

Exploitation of this vulnerability can lead to a deadlock situation, where the system becomes unresponsive due to locked resources being held indefinitely.

Reproduction

The vulnerability can be reproduced by invoking the 'netlink_set_err()' function in a context where interrupts are disabled. This can be done by using a netlink socket and sending a message that triggers the function, while simultaneously disabling interrupts. The 'netlink_diag' subsystem can be used to facilitate this process, as it interacts with the netlink set error functionality.

Remediation

The vulnerability has been addressed in the official Linux Git repository. Users can upgrade to the latest version to mitigate this issue.