CVE-2023-53731

/// Technical description

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

netlink: fix potential deadlock in netlink_set_err()

syzbot reported a possible deadlock in netlink_set_err() [1]

A similar issue was fixed in commit 1d482e666b8e ("netlink: disable IRQs

for netlink_lock_table()") in netlink_lock_table()

This patch adds IRQ safety to netlink_set_err() and __netlink_diag_dump()

which were not covered by cited commit.

[1]

WARNING: possible irq lock inversion dependency detected

6.4.0-rc6-syzkaller-00240-g4e9f0ec38852 #0 Not tainted

syz-executor.2/23011 just changed the state of lock:

ffffffff8e1a7a58 (nl_table_lock){.+.?}-{2:2}, at: netlink_set_err+0x2e/0x3a0 net/netlink/af_netlink.c:1612

but this lock was taken by another, SOFTIRQ-safe lock in the past:

(&local->queue_stop_reason_lock){..-.}-{2:2}

and interrupts could create inverse lock ordering between them.

other info that might help us debug this:

Possible interrupt unsafe locking scenario:

CPU0

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. 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.

/// References