🇰🇷 한글 설명
Linux 커널의 mlx5e 드라이버에서 프로필 설정 실패 시 mlx5e_priv 구조체가 0으로 초기화되어 발생하는 NULL 포인터 역참조 취약점입니다. 이로 인해 장치 제거(remove) 과정에서 커널 Oops(시스템 충돌)가 발생할 수 있습니다.
💡 쉬운 설명
네트워크 장치의 설정을 변경하다가 오류가 발생했을 때, 시스템이 잘못된 메모리 주소를 참조하여 컴퓨터가 갑자기 멈추거나 꺼질 수 있는 문제입니다.
🇺🇸 원문 (English)
In the Linux kernel, the following vulnerability has been resolved:
net/mlx5e: Pass netdev to mlx5e_destroy_netdev instead of priv
mlx5e_priv is an unstable structure that can be memset(0) if profile
attaching fails.
Pass netdev to mlx5e_destroy_netdev() to guarantee it will work on a
valid netdev.
On mlx5e_remove: Check validity of priv->profile, before attempting
to cleanup any resources that might be not there.
This fixes a kernel oops in mlx5e_remove when switchdev mode fails due
to change profile failure.
$ devlink dev eswitch set pci/0000:00:03.0 mode switchdev
Error: mlx5_core: Failed setting eswitch to offloads.
dmesg:
workqueue: Failed to create a rescuer kthread for wq "mlx5e": -EINTR
mlx5_core 0012:03:00.1: mlx5e_netdev_init_profile:6214:(pid 37199): mlx5e_priv_init failed, err=-12
mlx5_core 0012:03:00.1 gpu3rdma1: mlx5e_netdev_change_profile: new profile init failed, -12
workqueue: Failed to create a rescuer kthread for wq "mlx5e": -EINTR
mlx5_core 0012:03:00.1: mlx5e_netdev_init_profile:6214:(pid 37199): mlx5e_priv_init failed, err=-12
mlx5_core 0012:03:00.1 gpu3rdma1: mlx5e_netdev_change_profile: failed to rollback to orig profile, -12
$ devlink dev reload pci/0000:00:03.0 ==> oops
BUG: kernel NULL pointer dereference, address: 0000000000000370
PGD 0 P4D 0
Oops: Oops: 0000 [#1] SMP NOPTI
CPU: 15 UID: 0 PID: 520 Comm: devlink Not tainted 6.18.0-rc5+ #115 PREEMPT(voluntary)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-2.fc40 04/01/2014
RIP: 0010:mlx5e_dcbnl_dscp_app+0x23/0x100
RSP: 0018:ffffc9000083f8b8 EFLAGS: 00010286
RAX: ffff8881126fc380 RBX: ffff8881015ac400 RCX: ffffffff826ffc45
RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffff8881035109c0
RBP: ffff8881035109c0 R08: ffff888101e3e838 R09: ffff888100264e10
R10: ffffc9000083f898 R11: ffffc9000083f8a0 R12: ffff888101b921a0
R13: ffff888101b921a0 R14: ffff8881015ac9a0 R15: ffff8881015ac400
FS: 00007f789a3c8740(0000) GS:ffff88856aa59000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000370 CR3: 000000010b6c0001 CR4: 0000000000370ef0
Call Trace:
<TASK>
mlx5e_remove+0x57/0x110
device_release_driver_internal+0x19c/0x200
bus_remove_device+0xc6/0x130
device_del+0x160/0x3d0
? devl_param_driverinit_value_get+0x2d/0x90
mlx5_detach_device+0x89/0xe0
mlx5_unload_one_devl_locked+0x3a/0x70
mlx5_devlink_reload_down+0xc8/0x220
devlink_reload+0x7d/0x260
devlink_nl_reload_doit+0x45b/0x5a0
genl_family_rcv_msg_doit+0xe8/0x140
📍 영향받는 시스템
Linux kernel (mlx5e driver, specifically versions around 6.18.0-rc5+)
⚔️ 공격 벡터
로컬 사용자가 devlink 명령어를 사용하여 네트워크 프로필 변경 및 장치 재설정(reload)을 시도할 때 발생
🛡️ 대응 방법
mlx5e 드라이버의 프로필 유효성 검사 로직이 포함된 최신 Linux 커널로 업데이트
🔧 검증 코드
출력된 커널 버전이 취약점이 수정된 최신 패치 버전인지 확인합니다.