CVE-2026-90170 in Linux
요약
\~에 의해 VulDB • 2026. 09. 18.
리눅스 커널에서 다음 취약점이 해결되었습니다:
ksmbd: 필드를 역참조하기 전에 IPC 응답 길이를 검증하십시오.
ipc_validate_msg()는 사용자 공간 ksmbd 데몬이 제공하는 응답 버퍼(payload_sz, session_key_len, ngroups 등)의 길이 필드를 읽음으로써 예상 메시지 크기를 계산합니다. 이러한 필드는 해당 구조체가 포함될 만큼 충분히 큰지 여부를 확인하기 전에 버퍼에서 읽어오므로, 짧은 길이의 응답은 할당된 영역을 벗어나는 지점까지 판독하게 만듭니다.
handle_response()는 entry->response의 크기를 netlink 속성 길이(nla_len())만으로 결정하며 선두 핸들 읽기만 보호하므로, 데몬은 아래에 보이는 kmalloc-8 객체와 같은 매우 작은 응답을 설치할 수 있습니다. 그런 다음 ipc_msg_send_request()가 KSMBD_EVENT_RPC_REQUEST에 대해 ipc_validate_msg()를 호출하면, struct ksmbd_rpc_command로의 캐스팅이 8바이트 할당된 영역의 오프셋 8에서 resp->payload_sz를 판독합니다:
[ 3697.841381] ==================================================================
[ 3697.844099] BUG: KASAN: slab-out-of-bounds in ipc_msg_send_request+0x763/0x800
[ 3697.846604] Read of size 4 at addr ffff888105f95910 by task kworker/4:3/20682
[ 3697.849061]
[ 3697.849801] CPU: 4 UID: 0 PID: 20682 Comm: kworker/4:3 Not tainted 7.2.0-rc3-next-20260717-virtme #117 PREEMPT(lazy)
[ 3697.850077] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.17.0-debian-1.17.0-1 04/01/2014
[ 3697.850303] Workqueue: ksmbd-io handle_ksmbd_work
[ 3697.850592] Call Trace:
[ 3697.850794] <TASK>
[ 3697.850952] __dump_stack+0x21/0x60
[ 3697.851239] dump_stack_lvl+0xc2/0x100
[ 3697.851528] print_address_description+0x77/0x200
[ 3697.851816] ? ipc_msg_send_request+0x763/0x800
[ 3697.852024] print_report+0x58/0x70
[ 3697.852316] kasan_report+0x117/0x150
[ 3697.852585] ? down_write+0x146/0x1f0
[ 3697.852809] ? ipc_msg_send_request+0x763/0x800
[ 3697.853082] ipc_msg_send_request+0x763/0x800
[ 3697.853385] ? __pfx_ipc_msg_send_request+0x10/0x10
[ 3697.853604] ? kasan_unpoison+0x48/0x70
[ 3697.853936] ? __pfx___up_read+0x10/0x10
[ 3697.854221] ksmbd_rpc_ioctl+0x380/0x520
[ 3697.854542] ? __pfx_ksmbd_rpc_ioctl+0x10/0x10
[ 3697.854757] ? kasan_unpoison+0x48/0x70
[ 3697.854962] ? copy_from_kernel_nofault+0x32c/0x4e0
[ 3697.855166] ? kasan_unpoison+0x48/0x70
[ 3697.855416] fsctl_pipe_transceive+0x139/0x7a0
[ 3697.855705] ? __pfx_copy_from_kernel_nofault+0x10/0x10
[ 3697.855937] ? __pfx_fsctl_pipe_transceive+0x10/0x10
[ 3697.856388] ? __sanitizer_cov_trace_switch+0x7b/0x140
[ 3697.856620] smb2_ioctl+0x1141/0x3420
[ 3697.856994] ? __pfx_smb2_ioctl+0x10/0x10
[ 3697.857182] ? get_smb2_cmd_val+0xe3/0x1c0
[ 3697.857655] handle_ksmbd_work+0x9ad/0x15e0
[ 3697.858034] ? __pfx_handle_ksmbd_work+0x10/0x10
[ 3697.858251] ? lock_release+0xf7/0x360
[ 3697.858466] ? process_scheduled_works+0x954/0x1600
[ 3697.858698] ? process_scheduled_works+0x954/0x1600
[ 3697.858905] process_scheduled_works+0xc22/0x1600
[ 3697.859368] ? __pfx_process_scheduled_works+0x10/0x10
[ 3697.859637] ? __pfx_assign_work+0x10/0x10
[ 3697.859896] ? lock_is_held_type+0x7b/0x110
[ 3697.860146] worker_thread+0x975/0xee0
[ 3697.860524] ? __pfx_do_raw_spin_lock+0x10/0x10
[ 3697.860830] ? __kthread_parkme+0x21e/0x260
[ 3697.861105] kthread+0x3a6/0x490
[ 3697.861423] ? __pfx_worker_thread+0x10/0x10
[ 3697.861643] ? __pfx_kthread+0x10/0x10
[ 3697.861878] ret_from_fork+0x55a/0xa20
[ 3697.862194] ? __pfx_ret_from_fork+0x10/0x10
[ 3697.862480] ? __pfx_kthread+0x10/0x10
[ 3697.862714] ret_from_fork_asm+0x1a/0x30
[ 3697.862965] </TASK>
[ 3697.863039]
[ 3697.938882] Allocated by task 20761:
[ 3697.940257] kasan_save_track+0x3e/0x80
[ 3697.941782] __kasan_kmalloc+0x72/0x90
[ 3697.943228] __kvmalloc_node_noprof+0x3e9/0x6a0
[ 3697.944948] handle_generic_event+0x59b/0x750
[ 3697.946592] genl_family_rcv_msg_doit+0x3d6/0x560
[ 3697.946977] genl_rcv_msg+0x67c/0x900
[ 3697.947224] netlink_rcv_skb+0x286/0x580
[ 3697.947488] genl_rcv+0x2d/0x80
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