def generate_token(key, user_id, action_id='', when=None):
"""Generates a URL-safe token for the given user, action, time tuple.
Args:
key: secret key to use.
user_id: the user ID of the authenticated user.
action_id: a string identifier of the action they requested
authorization for.
when: the time in seconds since the epoch at which the user was
authorized for this action. If not set the current time is used.
Returns:
A string XSRF protection token.
"""
digester = hmac.new(_to_bytes(key, encoding='utf-8'))
digester.update(_to_bytes(str(user_id), encoding='utf-8'))
digester.update(DELIMITER)
digester.update(_to_bytes(action_id, encoding='utf-8'))
digester.update(DELIMITER)
when = _to_bytes(str(when or int(time.time())), encoding='utf-8')
digester.update(when)
digest = digester.digest()
token = base64.urlsafe_b64encode(digest + DELIMITER + when)
return token
def _get_private_key(private_key_pkcs8_text):
"""Get an RSA private key object from a pkcs8 representation."""
private_key_pkcs8_text = _to_bytes(private_key_pkcs8_text)
der = rsa.pem.load_pem(private_key_pkcs8_text, 'PRIVATE KEY')
asn1_private_key, _ = decoder.decode(der, asn1Spec=PrivateKeyInfo())
return rsa.PrivateKey.load_pkcs1(
asn1_private_key.getComponentByName('privateKey').asOctets(),
format='DER')
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')
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
def sign(self, message):
"""Signs a message.
Args:
message: string, Message to be signed.
Returns:
string, The signature of the message for the given key.
"""
message = _to_bytes(message, encoding='utf-8')
return PKCS1_v1_5.new(self._key).sign(SHA256.new(message))
def pkcs12_key_as_pem(private_key_text, private_key_password):
"""Convert the contents of a PKCS12 key to PEM using OpenSSL.
Args:
private_key_text: String. Private key.
private_key_password: String. Password for PKCS12.
Returns:
String. PEM contents of ``private_key_text``.
"""
decoded_body = base64.b64decode(private_key_text)
private_key_password = _to_bytes(private_key_password)
pkcs12 = crypto.load_pkcs12(decoded_body, private_key_password)
return crypto.dump_privatekey(crypto.FILETYPE_PEM, pkcs12.get_privatekey())
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.
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')
return PKCS1_v1_5.new(self._pubkey).verify(SHA256.new(message),
signature)
def verify_signed_jwt_with_certs(jwt, certs, audience=None):
"""Verify a JWT against public certs.
See http://self-issued.info/docs/draft-jones-json-web-token.html.
Args:
jwt: string, A JWT.
certs: dict, Dictionary where values of public keys in PEM format.
audience: string, The audience, 'aud', that this JWT should contain. If
None then the JWT's 'aud' parameter is not verified.
Returns:
dict, The deserialized JSON payload in the JWT.
Raises:
AppIdentityError: if any checks are failed.
"""
jwt = _to_bytes(jwt)
if jwt.count(b'.') != 2:
raise AppIdentityError(
'Wrong number of segments in token: %s' % (jwt,))
header, payload, signature = jwt.split(b'.')
message_to_sign = header + b'.' + payload
signature = _urlsafe_b64decode(signature)
# Parse token.
payload_bytes = _urlsafe_b64decode(payload)
try:
payload_dict = json.loads(_from_bytes(payload_bytes))
except:
raise AppIdentityError('Can\'t parse token: %s' % (payload_bytes,))
# Verify that the signature matches the message.
_verify_signature(message_to_sign, signature, certs.values())
# Verify the issued at and created times in the payload.
_verify_time_range(payload_dict)
# Check audience.
_check_audience(payload_dict, audience)
return payload_dict
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.
"""
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 _SendRecv():
"""Communicate with the Developer Shell server socket."""
port = int(os.getenv(DEVSHELL_ENV, 0))
if port == 0:
raise NoDevshellServer()
sock = socket.socket()
sock.connect(('localhost', port))
data = CREDENTIAL_INFO_REQUEST_JSON
msg = '%s\n%s' % (len(data), data)
sock.sendall(_to_bytes(msg, encoding='utf-8'))
header = sock.recv(6).decode()
if '\n' not in header:
raise CommunicationError('saw no newline in the first 6 bytes')
len_str, json_str = header.split('\n', 1)
to_read = int(len_str) - len(json_str)
if to_read > 0:
json_str += sock.recv(to_read, socket.MSG_WAITALL).decode()
return CredentialInfoResponse(json_str)
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.
"""
if is_x509_cert:
key_pem = _to_bytes(key_pem)
pemLines = key_pem.replace(b' ', b'').split()
certDer = _urlsafe_b64decode(b''.join(pemLines[1:-1]))
certSeq = DerSequence()
certSeq.decode(certDer)
tbsSeq = DerSequence()
tbsSeq.decode(certSeq[0])
pubkey = RSA.importKey(tbsSeq[6])
else:
pubkey = RSA.importKey(key_pem)
return PyCryptoVerifier(pubkey)
def sign_blob(self, blob):
# Ensure that it is bytes
blob = _to_bytes(blob, encoding='utf-8')
return (self._private_key_id,
rsa.pkcs1.sign(blob, self._private_key, 'SHA-256'))