🇰🇷 한글 설명
Linux 커널의 ath11k 드라이버에서 장치 복구 과정 중 MHI 전원 관리 상태 불일치로 인해 경고(warning)가 발생하는 취약점입니다. mhi_device_get_sync()가 장치를 깨우지 않는 상태에서 mhi_device_put()이 호출되어 dev_wake 값이 비정상적으로 유지되는 것이 원인입니다.
💡 쉬운 설명
무선 랜 카드가 오류로 인해 다시 시작될 때, 시스템 내부의 전원 관리 신호가 꼬여서 경고 메시지가 나타나는 문제입니다. 이는 시스템의 안정성에 영향을 줄 수 있는 소프트웨어적 오류입니다.
🇺🇸 원문 (English)
In the Linux kernel, the following vulnerability has been resolved:
ath11k: fix the warning of dev_wake in mhi_pm_disable_transition()
When test device recovery with below command, it has warning in message
as below.
echo assert > /sys/kernel/debug/ath11k/wcn6855\ hw2.0/simulate_fw_crash
echo assert > /sys/kernel/debug/ath11k/qca6390\ hw2.0/simulate_fw_crash
warning message:
[ 1965.642121] ath11k_pci 0000:06:00.0: simulating firmware assert crash
[ 1968.471364] ieee80211 phy0: Hardware restart was requested
[ 1968.511305] ------------[ cut here ]------------
[ 1968.511368] WARNING: CPU: 3 PID: 1546 at drivers/bus/mhi/core/pm.c:505 mhi_pm_disable_transition+0xb37/0xda0 [mhi]
[ 1968.511443] Modules linked in: ath11k_pci ath11k mac80211 libarc4 cfg80211 qmi_helpers qrtr_mhi mhi qrtr nvme nvme_core
[ 1968.511563] CPU: 3 PID: 1546 Comm: kworker/u17:0 Kdump: loaded Tainted: G W 5.17.0-rc3-wt-ath+ #579
[ 1968.511629] Hardware name: Intel(R) Client Systems NUC8i7HVK/NUC8i7HVB, BIOS HNKBLi70.86A.0067.2021.0528.1339 05/28/2021
[ 1968.511704] Workqueue: mhi_hiprio_wq mhi_pm_st_worker [mhi]
[ 1968.511787] RIP: 0010:mhi_pm_disable_transition+0xb37/0xda0 [mhi]
[ 1968.511870] Code: a9 fe ff ff 4c 89 ff 44 89 04 24 e8 03 46 f6 e5 44 8b 04 24 41 83 f8 01 0f 84 21 fe ff ff e9 4c fd ff ff 0f 0b e9 af f8 ff ff <0f> 0b e9 5c f8 ff ff 48 89 df e8 da 9e ee e3 e9 12 fd ff ff 4c 89
[ 1968.511923] RSP: 0018:ffffc900024efbf0 EFLAGS: 00010286
[ 1968.511969] RAX: 00000000ffffffff RBX: ffff88811d241250 RCX: ffffffffc0176922
[ 1968.512014] RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff888118a90a24
[ 1968.512059] RBP: ffff888118a90800 R08: 0000000000000000 R09: ffff888118a90a27
[ 1968.512102] R10: ffffed1023152144 R11: 0000000000000001 R12: ffff888118a908ac
[ 1968.512229] R13: ffff888118a90928 R14: dffffc0000000000 R15: ffff888118a90a24
[ 1968.512310] FS: 0000000000000000(0000) GS:ffff888234200000(0000) knlGS:0000000000000000
[ 1968.512405] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1968.512493] CR2: 00007f5538f443a8 CR3: 000000016dc28001 CR4: 00000000003706e0
[ 1968.512587] Call Trace:
[ 1968.512672] <TASK>
[ 1968.512751] ? _raw_spin_unlock_irq+0x1f/0x40
[ 1968.512859] mhi_pm_st_worker+0x3ac/0x790 [mhi]
[ 1968.512959] ? mhi_pm_mission_mode_transition.isra.0+0x7d0/0x7d0 [mhi]
[ 1968.513063] process_one_work+0x86a/0x1400
[ 1968.513184] ? pwq_dec_nr_in_flight+0x230/0x230
[ 1968.513312] ? move_linked_works+0x125/0x290
[ 1968.513416] worker_thread+0x6db/0xf60
[ 1968.513536] ? process_one_work+0x1400/0x1400
[ 1968.513627] kthread+0x241/0x2d0
[ 1968.513733] ? kthread_complete_and_exit+0x20/0x20
[ 1968.513821] ret_from_fork+0x22/0x30
[ 1968.513924] </TASK>
Reason is mhi_deassert_dev_wake() from mhi_device_put() is called
but mhi_assert_dev_wake() from __mhi_device_get_sync() is not called
in progress of recovery. Commit 8e0559921f9a ("bus: mhi: core:
Skip device wake in error or shutdown state") add check for the
pm_state of mhi in __mhi_device_get_sync(), and the pm_state is not
the normal state untill recovery is completed, so it leads the
dev_wake is not 0 and above warning print in mhi_pm_disable_transition()
while checking mhi_cntrl->dev_wake.
Add check in ath11k_pci_write32()/ath11k_pci_read32() to skip call
mhi_device_put() if mhi_device_get_sync() does not really do wake,
then the warning gone.
Tested-on: WCN6855 hw2.0 PCI WLAN.HSP.1.1-03003-QCAHSPSWPL_V1_V2_SILICONZ_LITE-2
📍 영향받는 시스템
Linux kernel (ath11k driver, MHI subsystem)
⚔️ 공격 벡터
로컬 권한을 가진 사용자가 디버그 인터페이스를 통해 펌웨어 충돌을 시뮬레이션하여 발생 가능
🛡️ 대응 방법
Linux 커널을 최신 버전으로 업데이트하여 ath11k_pci의 mhi_device_put() 호출 로직 수정 패치를 적용하십시오.
🔧 검증 코드
출력된 커널 버전이 해당 취약점이 수정된 패치 버전(commit 8e0559921f9a 이후)인지 확인하십시오.