🇰🇷 한글 설명
Linux 커널의 mt76 wed 드라이버에서 발생하는 취약점으로, MT7996 드라이버가 6GHz 링크(wed_hif2)를 사용할 때 잘못된 wed 참조를 사용하여 커널 크래시가 발생합니다. 드라이버 콜백 함수에서 적절한 wed 장치를 식별하지 못해 메모리 읽기 오류(Null pointer dereference 유사 증상)가 발생하며 시스템이 중단될 수 있습니다.
💡 쉬운 설명
무선 랜카드가 6GHz 대역을 사용할 때, 드라이버가 엉뚱한 메모리 주소를 참조하여 컴퓨터 시스템이 갑자기 멈추거나 꺼지는 현상이 발생합니다. 이는 소프트웨어가 통신 장치를 제어하는 과정에서 길을 잘못 찾아 발생하는 오류입니다.
🇺🇸 원문 (English)
In the Linux kernel, the following vulnerability has been resolved:
wifi: mt76: wed: use proper wed reference in mt76 wed driver callabacks
MT7996 driver can use both wed and wed_hif2 devices to offload traffic
from/to the wireless NIC. In the current codebase we assume to always
use the primary wed device in wed callbacks resulting in the following
crash if the hw runs wed_hif2 (e.g. 6GHz link).
[ 297.455876] Unable to handle kernel read from unreadable memory at virtual address 000000000000080a
[ 297.464928] Mem abort info:
[ 297.467722] ESR = 0x0000000096000005
[ 297.471461] EC = 0x25: DABT (current EL), IL = 32 bits
[ 297.476766] SET = 0, FnV = 0
[ 297.479809] EA = 0, S1PTW = 0
[ 297.482940] FSC = 0x05: level 1 translation fault
[ 297.487809] Data abort info:
[ 297.490679] ISV = 0, ISS = 0x00000005, ISS2 = 0x00000000
[ 297.496156] CM = 0, WnR = 0, TnD = 0, TagAccess = 0
[ 297.501196] GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
[ 297.506500] user pgtable: 4k pages, 39-bit VAs, pgdp=0000000107480000
[ 297.512927] [000000000000080a] pgd=08000001097fb003, p4d=08000001097fb003, pud=08000001097fb003, pmd=0000000000000000
[ 297.523532] Internal error: Oops: 0000000096000005 [#1] SMP
[ 297.715393] CPU: 2 UID: 0 PID: 45 Comm: kworker/u16:2 Tainted: G O 6.12.50 #0
[ 297.723908] Tainted: [O]=OOT_MODULE
[ 297.727384] Hardware name: Banana Pi BPI-R4 (2x SFP+) (DT)
[ 297.732857] Workqueue: nf_ft_offload_del nf_flow_rule_route_ipv6 [nf_flow_table]
[ 297.740254] pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[ 297.747205] pc : mt76_wed_offload_disable+0x64/0xa0 [mt76]
[ 297.752688] lr : mtk_wed_flow_remove+0x58/0x80
[ 297.757126] sp : ffffffc080fe3ae0
[ 297.760430] x29: ffffffc080fe3ae0 x28: ffffffc080fe3be0 x27: 00000000deadbef7
[ 297.767557] x26: ffffff80c5ebca00 x25: 0000000000000001 x24: ffffff80c85f4c00
[ 297.774683] x23: ffffff80c1875b78 x22: ffffffc080d42cd0 x21: ffffffc080660018
[ 297.781809] x20: ffffff80c6a076d0 x19: ffffff80c6a043c8 x18: 0000000000000000
[ 297.788935] x17: 0000000000000000 x16: 0000000000000001 x15: 0000000000000000
[ 297.796060] x14: 0000000000000019 x13: ffffff80c0ad8ec0 x12: 00000000fa83b2da
[ 297.803185] x11: ffffff80c02700c0 x10: ffffff80c0ad8ec0 x9 : ffffff81fef96200
[ 297.810311] x8 : ffffff80c02700c0 x7 : ffffff80c02700d0 x6 : 0000000000000002
[ 297.817435] x5 : 0000000000000400 x4 : 0000000000000000 x3 : 0000000000000000
[ 297.824561] x2 : 0000000000000001 x1 : 0000000000000800 x0 : ffffff80c6a063c8
[ 297.831686] Call trace:
[ 297.834123] mt76_wed_offload_disable+0x64/0xa0 [mt76]
[ 297.839254] mtk_wed_flow_remove+0x58/0x80
[ 297.843342] mtk_flow_offload_cmd+0x434/0x574
[ 297.847689] mtk_wed_setup_tc_block_cb+0x30/0x40
[ 297.852295] nf_flow_offload_ipv6_hook+0x7f4/0x964 [nf_flow_table]
[ 297.858466] nf_flow_rule_route_ipv6+0x438/0x4a4 [nf_flow_table]
[ 297.864463] process_one_work+0x174/0x300
[ 297.868465] worker_thread+0x278/0x430
[ 297.872204] kthread+0xd8/0xdc
[ 297.875251] ret_from_fork+0x10/0x20
[ 297.878820] Code: 928b5ae0 8b000273 91400a60 f943fa61 (79401421)
[ 297.884901] ---[ end trace 0000000000000000 ]---
Fix the issue detecting the proper wed reference to use running wed
callabacks.
📍 영향받는 시스템
Linux kernel (mt76 driver, specifically MT7996 hardware using 6GHz/wed_hif2)
⚔️ 공격 벡터
로컬 또는 네트워크 트래픽 오프로딩 과정에서 특정 하드웨어 조건(6GHz 연결)을 유도하여 커널 패닉 유발
🛡️ 대응 방법
Linux 커널을 최신 버전으로 업데이트하여 mt76 드라이버의 wed 참조 로직 수정 패치를 적용하십시오.
🔧 검증 코드
현재 커널 버전과 mt76 모듈의 정보를 확인하여 수정된 패치가 포함된 최신 커널인지 확인합니다.
uname -r && modinfo mt76 | grep version