52 lines
1.6 KiB
Python
Executable File
52 lines
1.6 KiB
Python
Executable File
#!/usr/bin/env python
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"""Check GPG v2 signature for a given public key."""
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import argparse
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import base64
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import io
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import logging
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from . import decode
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from .. import util
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log = logging.getLogger(__name__)
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def original_data(filename):
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"""Locate and load original file data, whose signature is provided."""
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parts = filename.rsplit('.', 1)
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if len(parts) == 2 and parts[1] in ('sig', 'asc'):
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log.debug('loading file %s', parts[0])
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return open(parts[0], 'rb').read()
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def verify(pubkey, sig_file):
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"""Verify correctness of public key and signature."""
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stream = open(sig_file, 'rb')
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if stream.name.endswith('.asc'):
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lines = stream.readlines()[3:-1]
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data = base64.b64decode(''.join(lines))
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payload, checksum = data[:-3], data[-3:]
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assert util.crc24(payload) == checksum
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stream = io.BytesIO(payload)
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signature, digest = decode.load_signature(stream, original_data(sig_file))
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decode.verify_digest(pubkey=pubkey, digest=digest,
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signature=signature['sig'], label='GPG signature')
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log.info('%s OK', sig_file)
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def main():
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"""Main function."""
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p = argparse.ArgumentParser()
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p.add_argument('pubkey')
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p.add_argument('signature')
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p.add_argument('-v', '--verbose', action='store_true', default=False)
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args = p.parse_args()
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logging.basicConfig(level=logging.DEBUG if args.verbose else logging.INFO,
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format='%(asctime)s %(levelname)-10s %(message)s')
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verify(pubkey=decode.load_public_key(open(args.pubkey, 'rb')),
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sig_file=args.signature)
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if __name__ == '__main__':
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main()
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