# Copyright 2015 Google Inc. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""OpenSSL Crypto-related routines for oauth2client."""
import base64
from OpenSSL import crypto
from oauth2client._helpers import _parse_pem_key
from oauth2client._helpers import _to_bytes
class OpenSSLVerifier(object):
"""Verifies the signature on a message."""
def __init__(self, pubkey):
"""Constructor.
Args:
pubkey: OpenSSL.crypto.PKey, The public key to verify with.
"""
self._pubkey = pubkey
def verify(self, message, signature):
"""Verifies a message against a signature.
Args:
message: string or bytes, The message to verify. If string, will be
encoded to bytes as utf-8.
signature: string or bytes, The signature on the message. If string,
will be encoded to bytes as utf-8.
Returns:
True if message was signed by the private key associated with the
public key that this object was constructed with.
"""
message = _to_bytes(message, encoding='utf-8')
signature = _to_bytes(signature, encoding='utf-8')
try:
crypto.verify(self._pubkey, signature, message, 'sha256')
return True
except crypto.Error:
return False
@staticmethod
def from_string(key_pem, is_x509_cert):
"""Construct a Verified instance from a string.
Args:
key_pem: string, public key in PEM format.
is_x509_cert: bool, True if key_pem is an X509 cert, otherwise it
is expected to be an RSA key in PEM format.
Returns:
Verifier instance.
Raises:
OpenSSL.crypto.Error: if the key_pem can't be parsed.
"""
key_pem = _to_bytes(key_pem)
if is_x509_cert:
pubkey = crypto.load_certificate(crypto.FILETYPE_PEM, key_pem)
else:
pubkey = crypto.load_privatekey(crypto.FILETYPE_PEM, key_pem)
return OpenSSLVerifier(pubkey)
class OpenSSLSigner(object):
"""Signs messages with a private key."""
def __init__(self, pkey):
"""Constructor.
Args:
pkey: OpenSSL.crypto.PKey (or equiv), The private key to sign with.
"""
self._key = pkey
def sign(self, message):
"""Signs a message.
Args:
message: bytes, Message to be signed.
Returns:
string, The signature of the message for the given key.
"""
message = _to_bytes(message, encoding='utf-8')
return crypto.sign(self._key, message, 'sha256')
@staticmethod
def from_string(key, password=b'notasecret'):
"""Construct a Signer instance from a string.
Args:
key: string, private key in PKCS12 or PEM format.
password: string, password for the private key file.
Returns:
Signer instance.
Raises:
OpenSSL.crypto.Error if the key can't be parsed.
"""
key = _to_bytes(key)
parsed_pem_key = _parse_pem_key(key)
if parsed_pem_key:
pkey = crypto.load_privatekey(crypto.FILETYPE_PEM, parsed_pem_key)
else:
password = _to_bytes(password, encoding='utf-8')
pkey = crypto.load_pkcs12(key, password).get_privatekey()
return OpenSSLSigner(pkey)
def pkcs12_key_as_pem(private_key_bytes, private_key_password):
"""Convert the contents of a PKCS#12 key to PEM using pyOpenSSL.
Args:
private_key_bytes: Bytes. PKCS#12 key in DER format.
private_key_password: String. Password for PKCS#12 key.
Returns:
String. PEM contents of ``private_key_bytes``.
"""
private_key_password = _to_bytes(private_key_password)
pkcs12 = crypto.load_pkcs12(private_key_bytes, private_key_password)
return crypto.dump_privatekey(crypto.FILETYPE_PEM,
pkcs12.get_privatekey())
