78 lines
2.6 KiB
Python
78 lines
2.6 KiB
Python
# Copyright 2014 Google Inc. All rights reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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import rsa
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from pyasn1.codec.der import decoder
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from pyasn1.type import univ
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from rsa import pkcs1
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# python-rsa lib hashes all messages it signs. ADB does it already, we just
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# need to slap a signature on top of already hashed message. Introduce "fake"
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# hashing algo for this.
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class _Accum(object):
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def __init__(self):
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self._buf = b''
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def update(self, msg):
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self._buf += msg
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def digest(self):
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return self._buf
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pkcs1.HASH_METHODS['SHA-1-PREHASHED'] = _Accum
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pkcs1.HASH_ASN1['SHA-1-PREHASHED'] = pkcs1.HASH_ASN1['SHA-1']
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def _load_rsa_private_key(pem):
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"""PEM encoded PKCS#8 private key -> rsa.PrivateKey."""
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# ADB uses private RSA keys in pkcs#8 format. 'rsa' library doesn't support
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# them natively. Do some ASN unwrapping to extract naked RSA key
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# (in der-encoded form). See https://www.ietf.org/rfc/rfc2313.txt.
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# Also http://superuser.com/a/606266.
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try:
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der = rsa.pem.load_pem(pem, 'PRIVATE KEY')
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keyinfo, _ = decoder.decode(der)
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if keyinfo[1][0] != univ.ObjectIdentifier(
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'1.2.840.113549.1.1.1'): # pragma: no cover
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raise ValueError('Not a DER-encoded OpenSSL private RSA key')
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private_key_der = keyinfo[2].asOctets()
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except IndexError: # pragma: no cover
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raise ValueError('Not a DER-encoded OpenSSL private RSA key')
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return rsa.PrivateKey.load_pkcs1(private_key_der, format='DER')
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class PythonRSASigner(object):
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"""Implements adb_protocol.AuthSigner using http://stuvel.eu/rsa."""
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@classmethod
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def FromRSAKeyPath(cls, rsa_key_path):
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with open(rsa_key_path + '.pub') as f:
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pub = f.read()
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with open(rsa_key_path) as f:
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priv = f.read()
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return cls(pub, priv)
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def __init__(self, pub=None, priv=None):
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self.priv_key = _load_rsa_private_key(priv)
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self.pub_key = pub
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def Sign(self, data):
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return rsa.sign(data, self.priv_key, 'SHA-1-PREHASHED')
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def GetPublicKey(self):
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return self.pub_key
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