CVE-2024-36286

/// Technical description

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

netfilter: nfnetlink_queue: acquire rcu_read_lock() in instance_destroy_rcu()

syzbot reported that nf_reinject() could be called without rcu_read_lock() :

WARNING: suspicious RCU usage

6.9.0-rc7-syzkaller-02060-g5c1672705a1a #0 Not tainted

net/netfilter/nfnetlink_queue.c:263 suspicious rcu_dereference_check() usage!

other info that might help us debug this:

rcu_scheduler_active = 2, debug_locks = 1

2 locks held by syz-executor.4/13427:

#0: ffffffff8e334f60 (rcu_callback){....}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline]

#0: ffffffff8e334f60 (rcu_callback){....}-{0:0}, at: rcu_do_batch kernel/rcu/tree.c:2190 [inline]

#0: ffffffff8e334f60 (rcu_callback){....}-{0:0}, at: rcu_core+0xa86/0x1830 kernel/rcu/tree.c:2471

#1: ffff88801ca92958 (&inst->lock){+.-.}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:356 [inline]

#1: ffff88801ca92958 (&inst->lock){+.-.}-{2:2}, at: nfqnl_flush net/n

/// 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