CVE-2024-35892

CVE Details

Release Date:

2024-05-19

Description

In the Linux kernel, the following vulnerability has been resolved:\nnet/sched: fix lockdep splat in qdisc_tree_reduce_backlog()\nqdisc_tree_reduce_backlog() is called with the qdisc lock held,\nnot RTNL.\nWe must use qdisc_lookup_rcu() instead of qdisc_lookup()\nsyzbot reported:\nWARNING: suspicious RCU usage\n6.1.74-syzkaller #0 Not tainted\n-----------------------------\nnet/sched/sch_api.c:305 suspicious rcu_dereference_protected() usage!\nother info that might help us debug this:\nrcu_scheduler_active = 2, debug_locks = 1\n3 locks held by udevd/1142:\n#0: ffffffff87c729a0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:306 [inline]\n#0: ffffffff87c729a0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:747 [inline]\n#0: ffffffff87c729a0 (rcu_read_lock){....}-{1:2}, at: net_tx_action+0x64a/0x970 net/core/dev.c:5282\n#1: ffff888171861108 (&sch->q.lock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:350 [inline]\n#1: ffff888171861108 (&sch->q.lock){+.-.}-{2:2}, at: net_tx_action+0x754/0x970 net/core/dev.c:5297\n#2: ffffffff87c729a0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:306 [inline]\n#2: ffffffff87c729a0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:747 [inline]\n#2: ffffffff87c729a0 (rcu_read_lock){....}-{1:2}, at: qdisc_tree_reduce_backlog+0x84/0x580 net/sched/sch_api.c:792\nstack backtrace:\nCPU: 1 PID: 1142 Comm: udevd Not tainted 6.1.74-syzkaller #0\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024\nCall Trace:\n\n[] __dump_stack lib/dump_stack.c:88 [inline]\n[] dump_stack_lvl+0x1b1/0x28f lib/dump_stack.c:106\n[] dump_stack+0x15/0x1e lib/dump_stack.c:113\n[] lockdep_rcu_suspicious+0x1b9/0x260 kernel/locking/lockdep.c:6592\n[] qdisc_lookup+0xac/0x6f0 net/sched/sch_api.c:305\n[] qdisc_tree_reduce_backlog+0x243/0x580 net/sched/sch_api.c:811\n[] pfifo_tail_enqueue+0x32c/0x4b0 net/sched/sch_fifo.c:51\n[] qdisc_enqueue include/net/sch_generic.h:833 [inline]\n[] netem_dequeue+0xeb3/0x15d0 net/sched/sch_netem.c:723\n[] dequeue_skb net/sched/sch_generic.c:292 [inline]\n[] qdisc_restart net/sched/sch_generic.c:397 [inline]\n[] __qdisc_run+0x249/0x1e60 net/sched/sch_generic.c:415\n[] qdisc_run+0xd6/0x260 include/net/pkt_sched.h:125\n[] net_tx_action+0x7c9/0x970 net/core/dev.c:5313\n[] __do_softirq+0x2bd/0x9bd kernel/softirq.c:616\n[] invoke_softirq kernel/softirq.c:447 [inline]\n[] __irq_exit_rcu+0xca/0x230 kernel/softirq.c:700\n[] irq_exit_rcu+0x9/0x20 kernel/softirq.c:712\n[] sysvec_apic_timer_interrupt+0x42/0x90 arch/x86/kernel/apic/apic.c:1107\n[] asm_sysvec_apic_timer_interrupt+0x1b/0x20 arch/x86/include/asm/idtentry.h:656

See more information about CVE-2024-35892 from MITRE CVE dictionary and NIST NVD

CVSS Scoring

NOTE: The following CVSS v3.1 metrics and score provided are preliminary and subject to review.

Base Score:	5.5	CVSS Vector:	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack Vector:	Local network	Attack Complexity:	Low
Privileges Required:	Low	User Interaction:	None
Scope:	Unchanged	Confidentiality Impact:	None
Integrity Impact:	None	Availability Impact:	High

Errata information

Platform	Errata	Release Date
Oracle Linux version 9 (kernel)	ELSA-2024-9315	2024-11-14