🇰🇷 한글 설명
Linux 커널의 SMB 클라이언트에서 채널 재연결 시 발생하는 취약점입니다. smb2_reconnect_server() 함수가 초기화되지 않은 dummy tcon을 전달하여 queue_delayed_work() 호출 시 커널 경고 및 불안정성을 유발할 수 있습니다.
💡 쉬운 설명
네트워크 연결이 끊겼다가 다시 연결될 때, 컴퓨터의 핵심 시스템(커널)이 잘못된 정보를 사용하여 오류를 일으키는 문제입니다. 이로 인해 시스템이 멈추거나 예상치 못한 동작을 할 수 있습니다.
🇺🇸 원문 (English)
In the Linux kernel, the following vulnerability has been resolved:
smb: client: fix warning when reconnecting channel
When reconnecting a channel in smb2_reconnect_server(), a dummy tcon
is passed down to smb2_reconnect() with ->query_interface
uninitialized, so we can't call queue_delayed_work() on it.
Fix the following warning by ensuring that we're queueing the delayed
worker from correct tcon.
WARNING: CPU: 4 PID: 1126 at kernel/workqueue.c:2498 __queue_delayed_work+0x1d2/0x200
Modules linked in: cifs cifs_arc4 nls_ucs2_utils cifs_md4 [last unloaded: cifs]
CPU: 4 UID: 0 PID: 1126 Comm: kworker/4:0 Not tainted 6.16.0-rc3 #5 PREEMPT(voluntary)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-4.fc42 04/01/2014
Workqueue: cifsiod smb2_reconnect_server [cifs]
RIP: 0010:__queue_delayed_work+0x1d2/0x200
Code: 41 5e 41 5f e9 7f ee ff ff 90 0f 0b 90 e9 5d ff ff ff bf 02 00
00 00 e8 6c f3 07 00 89 c3 eb bd 90 0f 0b 90 e9 57 f> 0b 90 e9 65 fe
ff ff 90 0f 0b 90 e9 72 fe ff ff 90 0f 0b 90 e9
RSP: 0018:ffffc900014afad8 EFLAGS: 00010003
RAX: 0000000000000000 RBX: ffff888124d99988 RCX: ffffffff81399cc1
RDX: dffffc0000000000 RSI: ffff888114326e00 RDI: ffff888124d999f0
RBP: 000000000000ea60 R08: 0000000000000001 R09: ffffed10249b3331
R10: ffff888124d9998f R11: 0000000000000004 R12: 0000000000000040
R13: ffff888114326e00 R14: ffff888124d999d8 R15: ffff888114939020
FS: 0000000000000000(0000) GS:ffff88829f7fe000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffe7a2b4038 CR3: 0000000120a6f000 CR4: 0000000000750ef0
PKRU: 55555554
Call Trace:
<TASK>
queue_delayed_work_on+0xb4/0xc0
smb2_reconnect+0xb22/0xf50 [cifs]
smb2_reconnect_server+0x413/0xd40 [cifs]
? __pfx_smb2_reconnect_server+0x10/0x10 [cifs]
? local_clock_noinstr+0xd/0xd0
? local_clock+0x15/0x30
? lock_release+0x29b/0x390
process_one_work+0x4c5/0xa10
? __pfx_process_one_work+0x10/0x10
? __list_add_valid_or_report+0x37/0x120
worker_thread+0x2f1/0x5a0
? __kthread_parkme+0xde/0x100
? __pfx_worker_thread+0x10/0x10
kthread+0x1fe/0x380
? kthread+0x10f/0x380
? __pfx_kthread+0x10/0x10
? local_clock_noinstr+0xd/0xd0
? ret_from_fork+0x1b/0x1f0
? local_clock+0x15/0x30
? lock_release+0x29b/0x390
? rcu_is_watching+0x20/0x50
? __pfx_kthread+0x10/0x10
ret_from_fork+0x15b/0x1f0
? __pfx_kthread+0x10/0x10
ret_from_fork_asm+0x1a/0x30
</TASK>
irq event stamp: 1116206
hardirqs last enabled at (1116205): [<ffffffff8143af42>] __up_console_sem+0x52/0x60
hardirqs last disabled at (1116206): [<ffffffff81399f0e>] queue_delayed_work_on+0x6e/0xc0
softirqs last enabled at (1116138): [<ffffffffc04562fd>] __smb_send_rqst+0x42d/0x950 [cifs]
softirqs last disabled at (1116136): [<ffffffff823d35e1>] release_sock+0x21/0xf0
📍 영향받는 시스템
Linux kernel (cifs module 사용 환경, 특히 6.16.0-rc3 및 관련 버전)
⚔️ 공격 벡터
네트워크 연결 상태를 조작하여 SMB 채널 재연결을 강제함으로써 발생 가능
🛡️ 대응 방법
Linux 커널을 최신 보안 패치가 적용된 버전으로 업데이트하십시오.
🔧 검증 코드
출력된 커널 버전이 취약점이 해결된 패치 버전인지 확인하십시오.