72 lines
1.8 KiB
Python
Executable File
72 lines
1.8 KiB
Python
Executable File
#!/usr/bin/python3
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import argparse
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import json
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import hashlib
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from OpenSSL import crypto
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import socket
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import struct
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import urllib.request
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parser = argparse.ArgumentParser(description='iconograph fetcher')
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parser.add_argument(
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'--base-url',
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dest='base_url',
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action='store',
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required=True)
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parser.add_argument(
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'--ca-cert',
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dest='ca_cert',
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action='store',
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required=True)
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parser.add_argument(
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'--image-type',
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dest='image_type',
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action='store',
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required=True)
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FLAGS = parser.parse_args()
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class Fetcher(object):
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_MAX_BP = 10000
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def __init__(self, base_url, image_type, ca_cert):
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self._base_url = base_url
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self._image_type = image_type
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with open(ca_cert, 'r') as fh:
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self._ca_cert = crypto.load_certificate(crypto.FILETYPE_PEM, fh.read())
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def _Unwrap(self, wrapped):
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cert = crypto.load_certificate(crypto.FILETYPE_PEM, wrapped['cert'])
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crypto.verify(
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cert,
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wrapped['sig'].encode('ascii'),
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wrapped['inner'].encode('ascii'),
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'sha256')
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def _GetManifest(self):
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url = '%s/%s.manifest.json' % (self._base_url, self._image_type)
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resp = urllib.request.urlopen(url).read().decode('utf8')
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return self._Unwrap(json.loads(resp))
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def _ChooseImage(self, manifest):
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hostname = socket.gethostname()
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hash_base = hashlib.sha256(hostname.encode('ascii'))
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for image in manifest:
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hashobj = hash_base.copy()
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hashobj.update(struct.pack('!L', image['timestamp']))
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my_bp = struct.unpack('!I', hashobj.digest()[-4:])[0] % self._MAX_BP
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if my_bp < image['rollout_‱']:
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return image
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def Fetch(self):
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manifest = self._GetManifest()
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#image = self._ChooseImage(manifest)
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#print(image)
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fetcher = Fetcher(FLAGS.base_url, FLAGS.image_type, FLAGS.ca_cert)
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fetcher.Fetch()
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