🇰🇷 한글 설명
Linux 커널의 mwifiex 드라이버에서 펌웨어가 제공하는 이벤트 길이(event->len)를 검증하지 않아 발생하는 취약점입니다. 공격자가 조작된 이벤트를 보내면 슬랩 메모리 범위를 벗어난 읽기(Out-of-bounds read)가 발생하거나 정수 언더플로우로 인해 잘못된 메모리 복사가 일어날 수 있습니다.
💡 쉬운 설명
와이파이 칩셋이 컴퓨터에 잘못된 정보를 전달할 때, 컴퓨터가 그 정보의 크기를 제대로 확인하지 않아 발생하는 문제입니다. 이를 통해 해커는 컴퓨터의 민감한 메모리 정보를 훔쳐보거나 시스템 오류를 일으킬 수 있습니다.
🇺🇸 원문 (English)
In the Linux kernel, the following vulnerability has been resolved:
wifi: mwifiex: bound uAP association event IEs to the event buffer
mwifiex_process_uap_event() handles EVENT_UAP_STA_ASSOC by exposing the
(re)association request IEs that the firmware copies into the event:
sinfo->assoc_req_ies = &event->data[len];
len = (u8 *)sinfo->assoc_req_ies - (u8 *)&event->frame_control;
sinfo->assoc_req_ies_len = le16_to_cpu(event->len) - (u16)len;
event->len is supplied by the device firmware and is never validated,
and the subtraction is unchecked. assoc_req_ies points into
adapter->event_body[MAX_EVENT_SIZE], a fixed-size array embedded in the
kmalloc()'d struct mwifiex_adapter.
On the ap_11n_enabled path mwifiex_set_sta_ht_cap() walks these IEs with
cfg80211_find_ie(), whose for_each_element() loop dereferences each
element header. A firmware-reported event->len larger than the bytes
actually received makes assoc_req_ies_len describe IEs that extend past
event_body, so the walk reads out of the adapter slab object, a
slab-out-of-bounds read (KASAN: slab-out-of-bounds in cfg80211_find_ie).
An event->len smaller than the header instead makes the int subtraction
negative, which wraps to a huge size_t when stored in assoc_req_ies_len.
The same length is handed to cfg80211_new_sta(), so a more modest
over-claim can also copy stale event_body bytes into the
NL80211_CMD_NEW_STATION notification.
A malicious or malfunctioning mwifiex device (USB/SDIO/PCIe) can deliver
such an event while the interface is in AP/uAP mode.
Validate event->len before use: reject a length that underflows the
header or that would place the IEs outside the event_body[] buffer the
event was copied into. event->len here is struct mwifiex_assoc_event.len,
a payload field internal to this event, not the transport frame length,
so it is validated in this handler rather than at the generic
MWIFIEX_TYPE_EVENT receive path, which only sees the event cause and the
transport frame length. The bound is against event_body[MAX_EVENT_SIZE]
rather than the actually-received length because the transports store the
event differently (USB and SDIO leave the 4-byte event header in
event_skb, PCIe strips it via skb_pull), whereas event_body is the single
fixed buffer all of them copy the event into. This is the event-path
analogue of the receive-path bounds checks added in commit 119585281617
("wifi: mwifiex: Fix OOB and integer underflow when rx packets").
📍 영향받는 시스템
Linux kernel (mwifiex driver 사용 환경)
⚔️ 공격 벡터
악의적이거나 오작동하는 mwifiex 장치(USB/SDIO/PCIe)를 통한 조작된 이벤트 전달
🛡️ 대응 방법
Linux 커널을 최신 보안 패치가 적용된 버전으로 업데이트하여 이벤트 길이 검증 로직을 적용해야 합니다.
🔧 검증 코드
현재 실행 중인 커널 버전을 확인하여 해당 취약점이 해결된 패치 버전인지 확인합니다.
📊 CVSS Vector String
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
💻 영향받는 소프트웨어
NVIDIA vGPU Guest Driver for Linux