CVE-2026-80666 in Linux
요약
\~에 의해 VulDB • 2026. 08. 28.
리눅스 커널에서 다음 취약점이 해결되었습니다:
블루투스: sco: sco_sock_timeout()의 Race Condition 수정
sco_sock_timeout()는 비동기적으로 실행되며 lock_sk(sk)를 사용합니다. 타이머가 동작하는 동안 소켓이 종료되면, 동일한 잠금(lock_sk(sk))을 두 번 획득하게 되어 데드락(deadlock)이 발생합니다.
CPU 0 CPU 1 ==================== ====================== sco_sock_close() sco_sock_timeout() lock_sk(sk) // <-- LOCK __sco_sock_close() sco_chan_del() sco_conn_put() sco_conn_free() disable_delayed_work_sync() lock(sk) // <-- 동일한 잠금
disable_delayed_work_sync()를 lock_sk(sk) 외부로 이동하여 sco_sock_timeout() 전에 lock_sk(sk)가 보유되지 않도록 함으로써 이 문제를 해결합니다.
Lockdep 스플래트(Lockdep splat):
WARNING: possible circular locking dependency detected 6.13.0-rc4 #7 Not tainted
syz-executor292/9514는 다음 잠금을 획득하려고 시도하고 있습니다: ffff8881115d5070 ((work_completion)(&(&conn->timeout_work)->work)){+.+.}-{0:0}, at: rcu_lock_acquire sect/v6.13-rc4/./include/linux/rcupdate.h:337 [inline]
ffff8881115d5070 ((work_completion)(&(&conn->timeout_work)->work)){+.+.}-{0:0}, at: rcu_read_lock sect/v6.13-rc4/./include/linux/rcupdate.h:849 [inline]
ffff8881115d5070 ((work_completion)(&(&conn->timeout_work)->work)){+.+.}-{0:0}, at: start_flush_work sect/v6.13-rc4/kernel/workqueue.c:4137 [inline]
ffff8881115d5070 ((work_completion)(&(&conn->timeout_work)->work)){+.+.}-{0:0}, at: __flush_work+0xd1/0xc40 sect/v6.13-rc4/kernel/workqueue.c:4195
하지만 작업자는 이미 다음 잠금을 보유하고 있습니다: ffff88807db3a258 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}, at: lock_sk sect/v6.13-rc4/./include/net/sock.h:1623 [inline]
ffff88807db3a258 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}, at: sco_sock_close+0x25/0x100 sect/v6.13-rc4/net/bluetooth/sco.c:524
이 잠금은 이미 새로운 잠금에 의존하고 있습니다.
기존의 종속성 체인(역순)은 다음과 같습니다:
-> #1 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}:
lock_acquire+0x1c4/0x520 sect/v6.13-rc4/kernel/locking/lockdep.c:5849 lock_sk_nested+0x48/0x130 sect/v6.13-rc4/net/core/sock.c:3622 lock_sk sect/v6.13-rc4/./include/net/sock.h:1623 [inline]
sco_sock_timeout+0xbe/0x270 sect/v6.13-rc4/net/bluetooth/sco.c:158 process_one_work sect/v6.13-rc4/kernel/workqueue.c:3229 [inline]
process_scheduled_works+0xa99/0x18f0 sect/v6.13-rc4/kernel/workqueue.c:3310 worker_thread+0x8a9/0xd80 sect/v6.13-rc4/kernel/workqueue.c:3391 kthread+0x2c6/0x360 sect/v6.13-rc4/kernel/kthread.c:389 ret_from_fork+0x4e/0x80 sect/v6.13-rc4/arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 sect/v6.13-rc4/arch/x86/entry/entry_64.S:244
-> #0 ((work_completion)(&(&conn->timeout_work)->work)){+.+.}-{0:0}:
check_prev_add sect/v6.13-rc4/kernel/locking/lockdep.c:3161 [inline]
check_prevs_add sect/v6.13-rc4/kernel/locking/lockdep.c:3280 [inline]
validate_chain+0x1888/0x5760 sect/v6.13-rc4/kernel/locking/lockdep.c:3904 __lock_acquire+0x13b4/0x2120 sect/v6.13-rc4/kernel/locking/lockdep.c:5226 lock_acquire+0x1c4/0x520 sect/v6.13-rc4/kernel/locking/lockdep.c:5849 touch_work_lockdep_map sect/v6.13-rc4/kernel/workqueue.c:3909 [inline]
start_flush_work sect/v6.13-rc4/kernel/workqueue.c:4163 [inline]
__flush_work+0x70f/0xc40 sect/v6.13-rc4/kernel/workqueue.c:4195 __cancel_work_sync sect/v6.13-rc4/kernel/workqueue.c:4351 [inline]
disable_delayed_work_sync+0xbb/0xf0 sect/v6.13-rc4/kernel/workqueue.c:4514 sco_conn_free sect/v6.13-rc4/net/bluetooth/sco.c:95 [inline]
kref_put sect/v6.13-rc4/./include/linux/kref.h:65 [inline]
sco_conn_put+0x18f/0x270 sect/v6.13-rc4/net/bluetooth/sco.c:107 sco_chan_del+0xe2/0x210 sect/v6.13-rc4/net/bluetooth/sco.c:236 sco_sock_close+0x8f/0x100 sect/v6.13-rc4/net/bluetooth/sco.c:526 sco_sock_release+0x62/0x2d0 sect/v6.13-rc4/net/blue... ---truncated---
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