69 lines
2.3 KiB
Python
Executable File
69 lines
2.3 KiB
Python
Executable File
#!/usr/bin/env python3
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import argparse
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import re
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import struct
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import subprocess
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import zlib
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def main():
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parser = argparse.ArgumentParser()
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parser.add_argument('--input-file', type=str, required=True)
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parser.add_argument('--output-file', type=str, required=True)
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parser.add_argument('--model', type=str, required=True)
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parser.add_argument('--region', type=str, required=True)
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parser.add_argument('--version', type=str, required=True)
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parser.add_argument('--encryption-block-size', type=str, required=True)
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parser.add_argument('--openssl-bin', type=str, required=True)
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parser.add_argument('--key', type=str, required=True)
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parser.add_argument('--iv', type=str, required=True)
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args = parser.parse_args()
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assert re.match(r'V[0-9]\.[0-9]\.[0-9]\.[0-9]',
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args.version), 'Version must start with Vx.x.x.x'
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encryption_block_size = int(args.encryption_block_size, 0)
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assert (encryption_block_size > 0 and encryption_block_size % 16 ==
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0), 'Encryption block size must be a multiple of the AES block size (16)'
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image = open(args.input_file, 'rb').read()
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image_enc = []
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for i in range(0, len(image), encryption_block_size):
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chunk = image[i:i + encryption_block_size]
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chunk += b'\x00' * ((-len(chunk)) % 16) # pad to AES block size (16)
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res = subprocess.run([
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args.openssl_bin,
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'enc',
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'-aes-256-cbc',
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'-nosalt',
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'-nopad',
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'-K', args.key,
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'-iv', args.iv
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],
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check=True, input=chunk, stdout=subprocess.PIPE)
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image_enc.append(res.stdout)
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image_enc = b''.join(image_enc)
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image_with_header = struct.pack(
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'>32s32s64s64s64s256s12sII',
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args.model.encode('ascii'),
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args.region.encode('ascii'),
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args.version.encode('ascii'),
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b'Thu Jan 1 00:00:00 1970', # static date for reproducibility
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b'', # reserved
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b'', # RSA signature - omitted for now
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b'encrpted_img',
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len(image_enc),
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encryption_block_size,
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) + image_enc
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checksum = zlib.crc32(image_with_header, 0xffffffff) ^ 0xffffffff
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with open(args.output_file, 'wb') as outfile:
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outfile.write(image_with_header)
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outfile.write(struct.pack('>I', checksum))
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if __name__ == "__main__":
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main()
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