🇰🇷 한글 설명
Linux 커널의 inet_diag 모듈에서 struct inet_diag_req_v2의 pad 필드가 초기화되지 않아 발생하는 취약점입니다. KMSAN 분석 결과, raw_lookup() 함수가 초기화되지 않은 메모리 값을 참조함으로써 정보 유출이나 예기치 않은 동작을 유발할 수 있음이 확인되었습니다.
💡 쉬운 설명
컴퓨터 메모리의 특정 공간을 깨끗이 비우지 않고 사용하면서, 이전에 남아있던 쓰레기 데이터가 시스템 동작에 영향을 줄 수 있는 문제입니다. 이로 인해 시스템의 민감한 정보가 노출되거나 프로그램이 비정상적으로 작동할 수 있습니다.
🇺🇸 원문 (English)
In the Linux kernel, the following vulnerability has been resolved:
inet_diag: Initialize pad field in struct inet_diag_req_v2
KMSAN reported uninit-value access in raw_lookup() [1]. Diag for raw
sockets uses the pad field in struct inet_diag_req_v2 for the
underlying protocol. This field corresponds to the sdiag_raw_protocol
field in struct inet_diag_req_raw.
inet_diag_get_exact_compat() converts inet_diag_req to
inet_diag_req_v2, but leaves the pad field uninitialized. So the issue
occurs when raw_lookup() accesses the sdiag_raw_protocol field.
Fix this by initializing the pad field in
inet_diag_get_exact_compat(). Also, do the same fix in
inet_diag_dump_compat() to avoid the similar issue in the future.
[1]
BUG: KMSAN: uninit-value in raw_lookup net/ipv4/raw_diag.c:49 [inline]
BUG: KMSAN: uninit-value in raw_sock_get+0x657/0x800 net/ipv4/raw_diag.c:71
raw_lookup net/ipv4/raw_diag.c:49 [inline]
raw_sock_get+0x657/0x800 net/ipv4/raw_diag.c:71
raw_diag_dump_one+0xa1/0x660 net/ipv4/raw_diag.c:99
inet_diag_cmd_exact+0x7d9/0x980
inet_diag_get_exact_compat net/ipv4/inet_diag.c:1404 [inline]
inet_diag_rcv_msg_compat+0x469/0x530 net/ipv4/inet_diag.c:1426
sock_diag_rcv_msg+0x23d/0x740 net/core/sock_diag.c:282
netlink_rcv_skb+0x537/0x670 net/netlink/af_netlink.c:2564
sock_diag_rcv+0x35/0x40 net/core/sock_diag.c:297
netlink_unicast_kernel net/netlink/af_netlink.c:1335 [inline]
netlink_unicast+0xe74/0x1240 net/netlink/af_netlink.c:1361
netlink_sendmsg+0x10c6/0x1260 net/netlink/af_netlink.c:1905
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg+0x332/0x3d0 net/socket.c:745
____sys_sendmsg+0x7f0/0xb70 net/socket.c:2585
___sys_sendmsg+0x271/0x3b0 net/socket.c:2639
__sys_sendmsg net/socket.c:2668 [inline]
__do_sys_sendmsg net/socket.c:2677 [inline]
__se_sys_sendmsg net/socket.c:2675 [inline]
__x64_sys_sendmsg+0x27e/0x4a0 net/socket.c:2675
x64_sys_call+0x135e/0x3ce0 arch/x86/include/generated/asm/syscalls_64.h:47
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xd9/0x1e0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Uninit was stored to memory at:
raw_sock_get+0x650/0x800 net/ipv4/raw_diag.c:71
raw_diag_dump_one+0xa1/0x660 net/ipv4/raw_diag.c:99
inet_diag_cmd_exact+0x7d9/0x980
inet_diag_get_exact_compat net/ipv4/inet_diag.c:1404 [inline]
inet_diag_rcv_msg_compat+0x469/0x530 net/ipv4/inet_diag.c:1426
sock_diag_rcv_msg+0x23d/0x740 net/core/sock_diag.c:282
netlink_rcv_skb+0x537/0x670 net/netlink/af_netlink.c:2564
sock_diag_rcv+0x35/0x40 net/core/sock_diag.c:297
netlink_unicast_kernel net/netlink/af_netlink.c:1335 [inline]
netlink_unicast+0xe74/0x1240 net/netlink/af_netlink.c:1361
netlink_sendmsg+0x10c6/0x1260 net/netlink/af_netlink.c:1905
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg+0x332/0x3d0 net/socket.c:745
____sys_sendmsg+0x7f0/0xb70 net/socket.c:2585
___sys_sendmsg+0x271/0x3b0 net/socket.c:2639
__sys_sendmsg net/socket.c:2668 [inline]
__do_sys_sendmsg net/socket.c:2677 [inline]
__se_sys_sendmsg net/socket.c:2675 [inline]
__x64_sys_sendmsg+0x27e/0x4a0 net/socket.c:2675
x64_sys_call+0x135e/0x3ce0 arch/x86/include/generated/asm/syscalls_64.h:47
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xd9/0x1e0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Local variable req.i created at:
inet_diag_get_exact_compat net/ipv4/inet_diag.c:1396 [inline]
inet_diag_rcv_msg_compat+0x2a6/0x530 net/ipv4/inet_diag.c:1426
sock_diag_rcv_msg+0x23d/0x740 net/core/sock_diag.c:282
CPU: 1 PID: 8888 Comm: syz-executor.6 Not tainted 6.10.0-rc4-00217-g35bb670d65fc #32
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-2.fc40 04/01/2014
📍 영향받는 시스템
Linux kernel (specifically versions around 6.10.0-rc4 and earlier)
⚔️ 공격 벡터
Netlink 소켓을 통한 inet_diag 요청을 보내어 초기화되지 않은 메모리 영역에 접근
🛡️ 대응 방법
Linux 커널을 최신 보안 패치가 적용된 버전으로 업데이트하여 inet_diag_get_exact_compat() 및 inet_diag_dump_compat() 함수 내 pad 필드 초기화 적용
🔧 검증 코드
출력된 커널 버전이 취약점이 해결된 패치 버전보다 낮은지 확인하십시오.