🇰🇷 한글 설명
리눅스 커널의 블루투스 HCI 스택에서 발생하는 전역 범위의 경계 외 참조(out-of-bounds) 취약점입니다. 특정 초기화 배열(amp_init1, amp_init2)에 유효하지 않은 종료 요소가 누락되어, hci_init_stage_sync 함수가 배열의 범위를 넘어 메모리를 계속 읽는 문제가 발생합니다.
💡 쉬운 설명
블루투스 기능을 켤 때 컴퓨터가 잘못된 메모리 영역을 읽으려고 시도하는 오류입니다. 이로 인해 시스템이 갑자기 멈추거나 보안 문제가 생길 수 있습니다.
🇺🇸 원문 (English)
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: HCI: Fix global-out-of-bounds
To loop a variable-length array, hci_init_stage_sync(stage) considers
that stage[i] is valid as long as stage[i-1].func is valid.
Thus, the last element of stage[].func should be intentionally invalid
as hci_init0[], le_init2[], and others did.
However, amp_init1[] and amp_init2[] have no invalid element, letting
hci_init_stage_sync() keep accessing amp_init1[] over its valid range.
This patch fixes this by adding {} in the last of amp_init1[] and
amp_init2[].
==================================================================
BUG: KASAN: global-out-of-bounds in hci_dev_open_sync (
/v6.2-bzimage/net/bluetooth/hci_sync.c:3154
/v6.2-bzimage/net/bluetooth/hci_sync.c:3343
/v6.2-bzimage/net/bluetooth/hci_sync.c:4418
/v6.2-bzimage/net/bluetooth/hci_sync.c:4609
/v6.2-bzimage/net/bluetooth/hci_sync.c:4689)
Read of size 8 at addr ffffffffaed1ab70 by task kworker/u5:0/1032
CPU: 0 PID: 1032 Comm: kworker/u5:0 Not tainted 6.2.0 #3
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04
Workqueue: hci1 hci_power_on
Call Trace:
<TASK>
dump_stack_lvl (/v6.2-bzimage/lib/dump_stack.c:107 (discriminator 1))
print_report (/v6.2-bzimage/mm/kasan/report.c:307
/v6.2-bzimage/mm/kasan/report.c:417)
? hci_dev_open_sync (/v6.2-bzimage/net/bluetooth/hci_sync.c:3154
/v6.2-bzimage/net/bluetooth/hci_sync.c:3343
/v6.2-bzimage/net/bluetooth/hci_sync.c:4418
/v6.2-bzimage/net/bluetooth/hci_sync.c:4609
/v6.2-bzimage/net/bluetooth/hci_sync.c:4689)
kasan_report (/v6.2-bzimage/mm/kasan/report.c:184
/v6.2-bzimage/mm/kasan/report.c:519)
? hci_dev_open_sync (/v6.2-bzimage/net/bluetooth/hci_sync.c:3154
/v6.2-bzimage/net/bluetooth/hci_sync.c:3343
/v6.2-bzimage/net/bluetooth/hci_sync.c:4418
/v6.2-bzimage/net/bluetooth/hci_sync.c:4609
/v6.2-bzimage/net/bluetooth/hci_sync.c:4689)
hci_dev_open_sync (/v6.2-bzimage/net/bluetooth/hci_sync.c:3154
/v6.2-bzimage/net/bluetooth/hci_sync.c:3343
/v6.2-bzimage/net/bluetooth/hci_sync.c:4418
/v6.2-bzimage/net/bluetooth/hci_sync.c:4609
/v6.2-bzimage/net/bluetooth/hci_sync.c:4689)
? __pfx_hci_dev_open_sync (/v6.2-bzimage/net/bluetooth/hci_sync.c:4635)
? mutex_lock (/v6.2-bzimage/./arch/x86/include/asm/atomic64_64.h:190
/v6.2-bzimage/./include/linux/atomic/atomic-long.h:443
/v6.2-bzimage/./include/linux/atomic/atomic-instrumented.h:1781
/v6.2-bzimage/kernel/locking/mutex.c:171
/v6.2-bzimage/kernel/locking/mutex.c:285)
? __pfx_mutex_lock (/v6.2-bzimage/kernel/locking/mutex.c:282)
hci_power_on (/v6.2-bzimage/net/bluetooth/hci_core.c:485
/v6.2-bzimage/net/bluetooth/hci_core.c:984)
? __pfx_hci_power_on (/v6.2-bzimage/net/bluetooth/hci_core.c:969)
? read_word_at_a_time (/v6.2-bzimage/./include/asm-generic/rwonce.h:85)
? strscpy (/v6.2-bzimage/./arch/x86/include/asm/word-at-a-time.h:62
/v6.2-bzimage/lib/string.c:161)
process_one_work (/v6.2-bzimage/kernel/workqueue.c:2294)
worker_thread (/v6.2-bzimage/./include/linux/list.h:292
/v6.2-bzimage/kernel/workqueue.c:2437)
? __pfx_worker_thread (/v6.2-bzimage/kernel/workqueue.c:2379)
kthread (/v6.2-bzimage/kernel/kthread.c:376)
? __pfx_kthread (/v6.2-bzimage/kernel/kthread.c:331)
ret_from_fork (/v6.2-bzimage/arch/x86/entry/entry_64.S:314)
</TASK>
The buggy address belongs to the variable:
amp_init1+0x30/0x60
The buggy address belongs to the physical page:
page:000000003a157ec6 refcount:1 mapcount:0 mapping:0000000000000000 ia
flags: 0x200000000001000(reserved|node=0|zone=2)
raw: 0200000000001000 ffffea0005054688 ffffea0005054688 000000000000000
raw: 0000000000000000 0000000000000000 00000001ffffffff 000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffffffffaed1aa00: f9 f9 f9 f9 00 00 00 00 f9 f9 f9 f9 00 00 00 00
ffffffffaed1aa80: 00 00 00 00 f9 f9 f9 f9 00 00 00 00 00 00 00 00
>ffffffffaed1ab00: 00 f9 f9 f9 f9 f9 f9 f9 00 00 00 00 00 00 f9 f9
---truncated---
📍 영향받는 시스템
Linux Kernel v6.2 및 블루투스 스택을 사용하는 시스템
⚔️ 공격 벡터
로컬 공격자가 블루투스 장치를 초기화하거나 특정 블루투스 프로토콜을 활성화하여 메모리 오류 유도
🛡️ 대응 방법
리눅스 커널을 최신 보안 패치가 적용된 버전으로 업데이트하여 amp_init 배열의 경계 검사 로직을 수정해야 합니다.
🔧 검증 코드
출력된 커널 버전이 취약점이 해결된 최신 패치 버전인지 확인합니다.