CVE-2024-49980

/// Technical description

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

vrf: revert "vrf: Remove unnecessary RCU-bh critical section"

This reverts commit 504fc6f4f7f681d2a03aa5f68aad549d90eab853.

dev_queue_xmit_nit is expected to be called with BH disabled.

__dev_queue_xmit has the following:

/* Disable soft irqs for various locks below. Also

* stops preemption for RCU.

*/

rcu_read_lock_bh();

VRF must follow this invariant. The referenced commit removed this

protection. Which triggered a lockdep warning:

================================

WARNING: inconsistent lock state

6.11.0 #1 Tainted: G W

--------------------------------

inconsistent {IN-SOFTIRQ-W} -> {SOFTIRQ-ON-W} usage.

btserver/134819 [HC0[0]:SC0[0]:HE1:SE1] takes:

ffff8882da30c118 (rlock-AF_PACKET){+.?.}-{2:2}, at: tpacket_rcv+0x863/0x3b30

{IN-SOFTIRQ-W} state was registered at:

lock_acquire+0x19a/0x4f0

_raw_spin_lock+0x27/0x40

packet_rcv+0xa33/0x1320

__netif_receiv

/// 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