CVE-2024-36286

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

netfilter: nfnetlinkqueue: acquire rcureadlock() in instancedestroy_rcu()

syzbot reported that nfreinject() could be called without rcuread_lock() :

WARNING: suspicious RCU usage 6.9.0-rc7-syzkaller-02060-g5c1672705a1a #0 Not tainted

net/netfilter/nfnetlinkqueue.c:263 suspicious rcudereference_check() usage!

other info that might help us debug this:

rcuscheduleractive = 2, debuglocks = 1 2 locks held by syz-executor.4/13427: #0: ffffffff8e334f60 (rcucallback){....}-{0:0}, at: rculockacquire include/linux/rcupdate.h:329 [inline] #0: ffffffff8e334f60 (rcucallback){....}-{0:0}, at: rcudobatch kernel/rcu/tree.c:2190 [inline] #0: ffffffff8e334f60 (rcucallback){....}-{0:0}, at: rcucore+0xa86/0x1830 kernel/rcu/tree.c:2471 #1: ffff88801ca92958 (&inst->lock){+.-.}-{2:2}, at: spinlockbh include/linux/spinlock.h:356 [inline] #1: ffff88801ca92958 (&inst->lock){+.-.}-{2:2}, at: nfqnlflush net/netfilter/nfnetlinkqueue.c:405 [inline] #1: ffff88801ca92958 (&inst->lock){+.-.}-{2:2}, at: instancedestroyrcu+0x30/0x220 net/netfilter/nfnetlinkqueue.c:172

stack backtrace: CPU: 0 PID: 13427 Comm: syz-executor.4 Not tainted 6.9.0-rc7-syzkaller-02060-g5c1672705a1a #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024 Call Trace: <IRQ> __dumpstack lib/dumpstack.c:88 [inline] dumpstacklvl+0x241/0x360 lib/dumpstack.c:114 lockdeprcususpicious+0x221/0x340 kernel/locking/lockdep.c:6712 nfreinject net/netfilter/nfnetlinkqueue.c:323 [inline] nfqnlreinject+0x6ec/0x1120 net/netfilter/nfnetlinkqueue.c:397 nfqnlflush net/netfilter/nfnetlinkqueue.c:410 [inline] instancedestroyrcu+0x1ae/0x220 net/netfilter/nfnetlinkqueue.c:172 rcudobatch kernel/rcu/tree.c:2196 [inline] rcucore+0xafd/0x1830 kernel/rcu/tree.c:2471 handlesoftirqs+0x2d6/0x990 kernel/softirq.c:554 __dosoftirq kernel/softirq.c:588 [inline] invokesoftirq kernel/softirq.c:428 [inline] _irqexitrcu+0xf4/0x1c0 kernel/softirq.c:637 irqexitrcu+0x9/0x30 kernel/softirq.c:649 instrsysvecapictimerinterrupt arch/x86/kernel/apic/apic.c:1043 [inline] sysvecapictimerinterrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1043 </IRQ> <TASK>