CVE-2024-49946

CVE Details

Release Date:

2024-10-21

Description

In the Linux kernel, the following vulnerability has been resolved:\nppp: do not assume bh is held in ppp_channel_bridge_input()\nNetworking receive path is usually handled from BH handler.\nHowever, some protocols need to acquire the socket lock, and\npackets might be stored in the socket backlog is the socket was\nowned by a user process.\nIn this case, release_sock(), __release_sock(), and sk_backlog_rcv()\nmight call the sk->sk_backlog_rcv() handler in process context.\nsybot caught ppp was not considering this case in\nppp_channel_bridge_input() :\nWARNING: inconsistent lock state\n6.11.0-rc7-syzkaller-g5f5673607153 #0 Not tainted\n--------------------------------\ninconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage.\nksoftirqd/1/24 [HC0[0]:SC1[1]:HE1:SE0] takes:\nffff0000db7f11e0 (&pch->downl){+.?.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline]\nffff0000db7f11e0 (&pch->downl){+.?.}-{2:2}, at: ppp_channel_bridge_input drivers/net/ppp/ppp_generic.c:2272 [inline]\nffff0000db7f11e0 (&pch->downl){+.?.}-{2:2}, at: ppp_input+0x16c/0x854 drivers/net/ppp/ppp_generic.c:2304\n{SOFTIRQ-ON-W} state was registered at:\nlock_acquire+0x240/0x728 kernel/locking/lockdep.c:5759\n__raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]\n_raw_spin_lock+0x48/0x60 kernel/locking/spinlock.c:154\nspin_lock include/linux/spinlock.h:351 [inline]\nppp_channel_bridge_input drivers/net/ppp/ppp_generic.c:2272 [inline]\nppp_input+0x16c/0x854 drivers/net/ppp/ppp_generic.c:2304\npppoe_rcv_core+0xfc/0x314 drivers/net/ppp/pppoe.c:379\nsk_backlog_rcv include/net/sock.h:1111 [inline]\n__release_sock+0x1a8/0x3d8 net/core/sock.c:3004\nrelease_sock+0x68/0x1b8 net/core/sock.c:3558\npppoe_sendmsg+0xc8/0x5d8 drivers/net/ppp/pppoe.c:903\nsock_sendmsg_nosec net/socket.c:730 [inline]\n__sock_sendmsg net/socket.c:745 [inline]\n__sys_sendto+0x374/0x4f4 net/socket.c:2204\n__do_sys_sendto net/socket.c:2216 [inline]\n__se_sys_sendto net/socket.c:2212 [inline]\n__arm64_sys_sendto+0xd8/0xf8 net/socket.c:2212\n__invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]\ninvoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49\nel0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132\ndo_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151\nel0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:712\nel0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:730\nel0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598\nirq event stamp: 282914\nhardirqs last enabled at (282914): [] __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:151 [inline]\nhardirqs last enabled at (282914): [] _raw_spin_unlock_irqrestore+0x38/0x98 kernel/locking/spinlock.c:194\nhardirqs last disabled at (282913): [] __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:108 [inline]\nhardirqs last disabled at (282913): [] _raw_spin_lock_irqsave+0x2c/0x7c kernel/locking/spinlock.c:162\nsoftirqs last enabled at (282904): [] softirq_handle_end kernel/softirq.c:400 [inline]\nsoftirqs last enabled at (282904): [] handle_softirqs+0xa3c/0xbfc kernel/softirq.c:582\nsoftirqs last disabled at (282909): [] run_ksoftirqd+0x70/0x158 kernel/softirq.c:928\nother info that might help us debug this:\nPossible unsafe locking scenario:\nCPU0\n----\nlock(&pch->downl);\n\nlock(&pch->downl);\n*** DEADLOCK ***\n1 lock held by ksoftirqd/1/24:\n#0: ffff80008f74dfa0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x10/0x4c include/linux/rcupdate.h:325\nstack backtrace:\nCPU: 1 UID: 0 PID: 24 Comm: ksoftirqd/1 Not tainted 6.11.0-rc7-syzkaller-g5f5673607153 #0\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024\nCall trace:\ndump_backtrace+0x1b8/0x1e4 arch/arm64/kernel/stacktrace.c:319\nshow_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:326\n__dump_sta\n---truncated---

See more information about CVE-2024-49946 from MITRE CVE dictionary and NIST NVD

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

CVSS v3 metrics

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

Errata information

Platform	Errata	Release Date
Oracle Linux version 8 (kernel-uek)	ELSA-2024-12887	2024-12-18
Oracle Linux version 9 (kernel-uek)	ELSA-2024-12887	2024-12-18