🇰🇷 한글 설명
Linux 커널의 Bluetooth MGMT 구성 요소에서 mgmt_pending 리스트에 대한 동시 접근을 적절히 보호하지 못하는 취약점이 발견되었습니다. 이로 인해 race condition이 발생하여 slab-use-after-free 오류와 함께 시스템 크래시가 발생할 수 있습니다.
💡 쉬운 설명
블루투스 기능을 처리하는 과정에서 여러 명령이 동시에 들어올 때 데이터가 꼬이는 문제가 있습니다. 이로 인해 컴퓨터 시스템이 갑자기 멈추거나 꺼질 수 있습니다.
🇺🇸 원문 (English)
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: MGMT: Protect mgmt_pending list with its own lock
This uses a mutex to protect from concurrent access of mgmt_pending
list which can cause crashes like:
==================================================================
BUG: KASAN: slab-use-after-free in hci_sock_get_channel+0x60/0x68 net/bluetooth/hci_sock.c:91
Read of size 2 at addr ffff0000c48885b2 by task syz.4.334/7318
CPU: 0 UID: 0 PID: 7318 Comm: syz.4.334 Not tainted 6.15.0-rc7-syzkaller-g187899f4124a #0 PREEMPT
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call trace:
show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:466 (C)
__dump_stack+0x30/0x40 lib/dump_stack.c:94
dump_stack_lvl+0xd8/0x12c lib/dump_stack.c:120
print_address_description+0xa8/0x254 mm/kasan/report.c:408
print_report+0x68/0x84 mm/kasan/report.c:521
kasan_report+0xb0/0x110 mm/kasan/report.c:634
__asan_report_load2_noabort+0x20/0x2c mm/kasan/report_generic.c:379
hci_sock_get_channel+0x60/0x68 net/bluetooth/hci_sock.c:91
mgmt_pending_find+0x7c/0x140 net/bluetooth/mgmt_util.c:223
pending_find net/bluetooth/mgmt.c:947 [inline]
remove_adv_monitor+0x44/0x1a4 net/bluetooth/mgmt.c:5445
hci_mgmt_cmd+0x780/0xc00 net/bluetooth/hci_sock.c:1712
hci_sock_sendmsg+0x544/0xbb0 net/bluetooth/hci_sock.c:1832
sock_sendmsg_nosec net/socket.c:712 [inline]
__sock_sendmsg net/socket.c:727 [inline]
sock_write_iter+0x25c/0x378 net/socket.c:1131
new_sync_write fs/read_write.c:591 [inline]
vfs_write+0x62c/0x97c fs/read_write.c:684
ksys_write+0x120/0x210 fs/read_write.c:736
__do_sys_write fs/read_write.c:747 [inline]
__se_sys_write fs/read_write.c:744 [inline]
__arm64_sys_write+0x7c/0x90 fs/read_write.c:744
__invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49
el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
el0_svc+0x58/0x17c arch/arm64/kernel/entry-common.c:767
el0t_64_sync_handler+0x78/0x108 arch/arm64/kernel/entry-common.c:786
el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600
Allocated by task 7037:
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x40/0x78 mm/kasan/common.c:68
kasan_save_alloc_info+0x44/0x54 mm/kasan/generic.c:562
poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
__kasan_kmalloc+0x9c/0xb4 mm/kasan/common.c:394
kasan_kmalloc include/linux/kasan.h:260 [inline]
__do_kmalloc_node mm/slub.c:4327 [inline]
__kmalloc_noprof+0x2fc/0x4c8 mm/slub.c:4339
kmalloc_noprof include/linux/slab.h:909 [inline]
sk_prot_alloc+0xc4/0x1f0 net/core/sock.c:2198
sk_alloc+0x44/0x3ac net/core/sock.c:2254
bt_sock_alloc+0x4c/0x300 net/bluetooth/af_bluetooth.c:148
hci_sock_create+0xa8/0x194 net/bluetooth/hci_sock.c:2202
bt_sock_create+0x14c/0x24c net/bluetooth/af_bluetooth.c:132
__sock_create+0x43c/0x91c net/socket.c:1541
sock_create net/socket.c:1599 [inline]
__sys_socket_create net/socket.c:1636 [inline]
__sys_socket+0xd4/0x1c0 net/socket.c:1683
__do_sys_socket net/socket.c:1697 [inline]
__se_sys_socket net/socket.c:1695 [inline]
__arm64_sys_socket+0x7c/0x94 net/socket.c:1695
__invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49
el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
el0_svc+0x58/0x17c arch/arm64/kernel/entry-common.c:767
el0t_64_sync_handler+0x78/0x108 arch/arm64/kernel/entry-common.c:786
el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600
Freed by task 6607:
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x40/0x78 mm/kasan/common.c:68
kasan_save_free_info+0x58/0x70 mm/kasan/generic.c:576
poison_slab_object mm/kasan/common.c:247 [inline]
__kasan_slab_free+0x68/0x88 mm/kasan/common.c:264
kasan_slab_free include/linux/kasan.h:233 [inline
---truncated---
📍 영향받는 시스템
Linux kernel (6.15.0-rc7 및 관련 Bluetooth 스택 사용 버전)
⚔️ 공격 벡터
로컬 또는 원격에서 블루투스 관리 명령(mgmt commands)을 비정상적으로 빠르게 반복 전송하여 레이스 컨디션 유도
🛡️ 대응 방법
Linux 커널을 최신 보안 패치가 적용된 버전으로 업데이트하여 mgmt_pending 리스트에 뮤텍스(mutex) 잠금이 적용된 버전을 사용하십시오.
🔧 검증 코드
출력된 커널 버전이 취약점이 해결된 패치 버전 이후인지 확인하십시오.