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vsphere-automation-sdk-python/samples/vsphere/common/sso.py

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2016-10-26 19:08:23 -04:00
"""
* *******************************************************
* Copyright VMware, Inc. 2013, 2016. All Rights Reserved.
* *******************************************************
*
* DISCLAIMER. THIS PROGRAM IS PROVIDED TO YOU "AS IS" WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, WHETHER ORAL OR WRITTEN,
* EXPRESS OR IMPLIED. THE AUTHOR SPECIFICALLY DISCLAIMS ANY IMPLIED
* WARRANTIES OR CONDITIONS OF MERCHANTABILITY, SATISFACTORY QUALITY,
* NON-INFRINGEMENT AND FITNESS FOR A PARTICULAR PURPOSE.
"""
__author__ = 'VMware, Inc.'
__copyright__ = 'Copyright 2013, 2016 VMware, Inc. All rights reserved.'
# Standard library imports.
try:
import httplib
except ImportError:
import http.client as httplib
import base64
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import cgi
import hashlib
import re
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import sys
import time
from uuid import uuid4
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try:
from StringIO import StringIO
except ImportError:
from io import StringIO
try:
from urlparse import urlparse
except ImportError:
from urllib.parse import urlparse
# Third-party imports.
from lxml import etree
def _extract_certificate(cert):
"""
Extract DER certificate/private key from DER/base64-ed DER/PEM string.
@type cert: C{str}
@param cert: Certificate/private key in one of three supported formats.
@rtype: C{str}
@return: Certificate/private key in DER (binary ASN.1) format.
"""
if not cert:
raise IOError('Empty certificate')
signature = cert[0]
# DER certificate is sequence. ASN.1 sequence is 0x30.
if signature == '\x30':
return cert
# PEM without preamble. Base64-encoded 0x30 is 0x4D.
if signature == '\x4D':
return base64.b64decode(cert)
# PEM with preamble. Starts with '-'.
if signature == '-':
return base64.b64decode(re.sub('-----[A-Z ]*-----', '', cert))
# Unknown format.
raise IOError('Invalid certificate file format')
class SoapException(Exception):
"""
Exception raised in case of STS request failure.
"""
def __init__(self, soap_msg, fault_code, fault_string):
"""
Initializer for SoapException.
@type soap_msg: C{str}
@param soap_msg: the soap fault XML returned by STS
@type fault_code: C{str}
@param fault_code: The fault code returned by STS.
@type fault_string: C{str}
@param fault_string: The fault string returned by STS.
"""
self._soap_msg = soap_msg
self._fault_code = fault_code
self._fault_string = fault_string
Exception.__init__(self)
def __str__(self):
"""
Returns the string representation of SoapException.
@rtype: C{str}
@return: string representation of SoapException
"""
return ("SoapException:\nfaultcode: %(_fault_code)s\n"
"faultstring: %(_fault_string)s\n"
"faultxml: %(_soap_msg)s" % self.__dict__)
class SSOHTTPSConnection(httplib.HTTPSConnection):
"""
An HTTPS class that verifies server's certificate on connect.
"""
def __init__(self, *args, **kwargs):
"""
Initializer. See httplib.HTTPSConnection for other arguments
than thumbprint and server_cert.
At least one of thumbprint, server_cert should be provided,
otherwise server certificate is not validated.
@type thumbprint: C(str)
@param thumbprint: Expected SHA-1 thumbprint of the server
certificate. May be None.
@type server_cert: C(str)
@param server_cert: File with expected server certificate.
May be None.
"""
self.server_thumbprint = kwargs.pop('thumbprint')
if self.server_thumbprint is not None:
self.server_thumbprint = re.sub(':', '',
self.server_thumbprint.lower())
server_cert_path = kwargs.pop('server_cert')
if server_cert_path is not None:
with open(server_cert_path, 'rb') as f:
server_cert = f.read()
self.server_cert = _extract_certificate(server_cert)
else:
self.server_cert = None
httplib.HTTPSConnection.__init__(self, *args, **kwargs)
def _check_cert(self, peerCert):
"""
Verify that peer certificate matches one we expect.
@type peerCert: C(str)
@param peerCert: Server certificate in DER format.
@rtype: boolean
@return: True if peerCert is acceptable. False otherwise.
"""
if self.server_cert is not None:
if peerCert != self.server_cert:
return False
if self.server_thumbprint is not None:
thumbprint = hashlib.sha1(peerCert).hexdigest().lower() # pylint: disable=E1101
if thumbprint != self.server_thumbprint:
return False
return True
def connect(self):
"""
Connect method: connects to the remote system, and upon
successful connection validates certificate.
Throws an exception when something is wrong. See
httplib.HTTPSConnection.connect() for details.
"""
httplib.HTTPSConnection.connect(self)
if not self._check_cert(self.sock.getpeercert(True)):
self.sock.close()
self.sock = None
raise IOError('Invalid certificate')
class SsoAuthenticator(object):
"""
A class to handle the transport layer communication between the client and
the STS service.
"""
def __init__(self,
sts_url,
sts_cert=None,
thumbprint=None
):
"""
Initializer for SsoAuthenticator.
@type sts_url: C{str}
@param sts_url: URL for the Security Token Service. Usually
obtained by querying Component Manager.
@type sts_cert: C{str}
@param sts_cert: The file with public key of the Security
Token Service. Usually obtained from
Component Manager and written to the file.
@type thumbprint: C{str}
@param thumbprint: The SHA-1 thumbprint of the certificate used
by the Security Token Service. It is same
thumbprint you can pass to pyVmomi SoapAdapter.
"""
self._sts_cert = sts_cert
self._sts_url = sts_url
self._sts_thumbprint = thumbprint
def perform_request(self,
soap_message,
public_key=None,
private_key=None,
ssl_context=None):
"""
Performs a Holder-of-Key SAML token request using the service user's
certificates or a bearer token request using the user credentials.
@type soap_message: C{str}
@param soap_message: Authentication SOAP request.
@type public_key: C{str}
@param public_key: File containing the public key for the service
user registered with SSO, in PEM format.
@type private_key: C{str}
@param private_key: File containing the private key for the service
user registered with SSO, in PEM format.
@type ssl_context: ssl.SSLContext
@param ssl_context: Context describing the various SSL options.
@rtype: C{str}
@return: Response received from the STS after the HoK request.
"""
parsed = urlparse(self._sts_url)
host = parsed.netloc # pylint: disable=E1101
import ssl
if ssl_context and hasattr(ssl, '_create_unverified_context'):
# Python 2.7.9 has stronger SSL certificate validation, so we need
# to pass in a context when dealing with self-signed certificates.
webservice = SSOHTTPSConnection(host=host,
key_file=private_key,
cert_file=public_key,
server_cert=self._sts_cert,
thumbprint=self._sts_thumbprint,
context=ssl_context)
else:
# Versions of Python before 2.7.9 don't support the context
# parameter, so if it wan't provided, don't pass it on.
webservice = SSOHTTPSConnection(host=host,
key_file=private_key,
cert_file=public_key,
server_cert=self._sts_cert,
thumbprint=self._sts_thumbprint)
webservice.putrequest("POST", parsed.path, skip_host=True) # pylint: disable=E1101
webservice.putheader("Host", host)
webservice.putheader("User-Agent", "VMware/pyVmomi")
webservice.putheader("Accept", "text/xml, multipart/related")
webservice.putheader("Content-type", "text/xml; charset=\"UTF-8\"")
webservice.putheader("Content-length", "%d" % len(soap_message))
webservice.putheader("Connection", "keep-alive")
webservice.putheader("SOAPAction",
"http://docs.oasis-open.org/ws-sx/ws-trust/200512/RST/Issue")
webservice.endheaders()
if sys.version_info[0] >= 3: # Python 3
webservice.send(bytes(soap_message, 'UTF-8'))
else:
webservice.send(soap_message)
saml_response = webservice.getresponse()
if saml_response.status != 200:
fault = saml_response.read()
# Best effort at figuring out a SOAP fault.
if saml_response.status == 500 and fault and 'faultcode' in fault:
fault_xml = etree.fromstring(fault)
parsed_fault = fault_xml.xpath("//text()")
if len(parsed_fault) == 2:
raise SoapException(fault, *parsed_fault)
raise Exception("Got response %s: %s\n%s" %
(saml_response.status, saml_response.msg, fault))
return saml_response.read()
def get_bearer_saml_assertion(self,
username,
password,
public_key=None,
private_key=None,
request_duration=60,
token_duration=600,
delegatable=False,
renewable=False,
ssl_context=None):
"""
Extracts the assertion from the Bearer Token received from the Security
Token Service.
@type username: C{str}
@param username: Username for the user for which bearer token
needs to be requested.
@type password: C{str}
@param password: Password for the user for which bearer token
needs to be requested.
@type public_key: C{str}
@param public_key: File containing the public key for the service
user registered with SSO, in PEM format.
@type private_key: C{str}
@param private_key: File containing the private key for the service
user registered with SSO, in PEM format.
@type request_duration: C{long}
@param request_duration: The duration for which the request is valid. If
the STS receives this request after this
duration, it is assumed to have expired. The
duration is in seconds and the default is 60s.
@type token_duration: C{long}
@param token_duration: The duration for which the SAML token is issued
for. The duration is specified in seconds and
the default is 600s.
@type delegatable: C{boolean}
@param delegatable: Whether the generated token is delegatable or not
The default value is False
@type ssl_context: ssl.SSLContext
@param ssl_context: Context describing the various SSL options.
@rtype: C{str}
@return: The SAML assertion.
"""
request = SecurityTokenRequest(username=username,
password=password,
public_key=public_key,
private_key=private_key,
request_duration=request_duration,
token_duration=token_duration)
soap_message = request.construct_bearer_token_request(
delegatable=delegatable, renewable=renewable)
bearer_token = self.perform_request(soap_message,
public_key,
private_key,
ssl_context)
if sys.version_info[0] >= 3:
return etree.tostring(
_extract_element(etree.fromstring(bearer_token),
'Assertion',
{'saml2': "urn:oasis:names:tc:SAML:2.0:assertion"}),
pretty_print=False).decode('utf-8')
else:
return etree.tostring(
_extract_element(etree.fromstring(bearer_token),
'Assertion',
{'saml2': "urn:oasis:names:tc:SAML:2.0:assertion"}),
pretty_print=False)
class SecurityTokenRequest(object):
"""
SecurityTokenRequest class handles the serialization of request to the STS
for a SAML token.
"""
# pylint: disable=R0902
def __init__(self,
username=None,
password=None,
public_key=None,
private_key=None,
request_duration=60,
token_duration=600):
"""
Initializer for the SecurityToken Request class.
@type username: C{str}
@param username: Username for the user for which bearer token
needs to be requested.
@type password: C{str}
@param password: Password for the user for which bearer token
needs to be requested.
@type public_key: C{str}
@param public_key: The file containing the public key of the
service account requesting the SAML token.
@type private_key: C{str}
@param private_key: The file containing the private key of the
service account requesting the SAML token.
@type request_duration: C{long}
@param request_duration: The duration for which the request is valid. If
the STS receives this request after this
duration, it is assumed to have expired. The
duration is specified in seconds and default is
60s.
@type token_duration: C{long}
@param token_duraiton: The duration for which the SAML token is issued
for. The duration is specified in seconds and
the default is 600s.
"""
self._timestamp_id = _generate_id()
self._signature_id = _generate_id()
self._request_id = _generate_id()
self._security_token_id = _generate_id()
current = time.time()
self._created = time.strftime(TIME_FORMAT,
time.gmtime(current))
self._expires = time.strftime(TIME_FORMAT,
time.gmtime(current + token_duration))
self._request_expires = time.strftime(TIME_FORMAT,
time.gmtime(current +
request_duration))
self._timestamp = TIMESTAMP_TEMPLATE % self.__dict__
self._username = cgi.escape(username) if username else username
self._password = cgi.escape(password) if password else password
self._public_key_file = public_key
self._private_key_file = private_key
self._act_as_token = None
self._renewable = str(False).lower()
self._delegatable = str(False).lower()
self._use_key = ''
self._private_key = None
self._binary_exchange = None
self._public_key = None
def construct_bearer_token_request(self, delegatable=False, renewable=False):
"""
Constructs the actual Bearer token SOAP request.
@type delegatable: C{boolean}
@param delegatable: Whether the generated token is delegatable or not
@type renewable: C{boolean}
@param renewable: Whether the generated token is renewable or not
The default value is False
@rtype: C{str}
@return: Bearer token SOAP request.
"""
self._key_type = "http://docs.oasis-open.org/ws-sx/ws-trust/200512/Bearer"
self._security_token = USERNAME_TOKEN_TEMPLATE % self.__dict__
self._delegatable = str(delegatable).lower()
self._renewable = str(renewable).lower()
return _canonicalize(REQUEST_TEMPLATE % self.__dict__)
def _generate_id():
"""
An internal helper method to generate UUIDs.
@rtype: C{str}
@return: UUID
"""
return "_%s" % uuid4()
def _canonicalize(xml_string):
"""
Given an xml string, canonicalize the string per
U{http://www.w3.org/2001/10/xml-exc-c14n#}
@type xml_string: C{str}
@param xml_string: The XML string that needs to be canonicalized.
@rtype: C{str}
@return: Canonicalized string.
"""
string = StringIO(xml_string)
parser = etree.XMLParser(remove_blank_text=True)
tree = etree.parse(string, parser=parser)
# io.StringIO only accepts Unicode input (i.e. u"multibyte string"), while StringIO.StringIO accepts either 8 bit input or unicode input.
if sys.version_info[0] >= 3:
from io import BytesIO
string = BytesIO()
tree.write_c14n(string, exclusive=True, with_comments=False)
return string.getvalue().decode('utf-8')
else:
string = StringIO()
tree.write_c14n(string, exclusive=True, with_comments=False)
return string.getvalue()
def _extract_element(xml, element_name, namespace):
"""
An internal method provided to extract an element from the given XML.
@type xml: C{str}
@param xml: The XML string from which the element will be extracted.
@type element_name: C{str}
@param element_name: The element that needs to be extracted from the XML.
@type namespace: dict
@param namespace: A dict containing the namespace of the element to be
extracted.
@rtype: etree element.
@return: The extracted element.
"""
assert(len(namespace) == 1)
result = xml.xpath("//%s:%s" % (list(namespace.keys())[0], element_name), # python 3.x dict.keys() returns a view
namespaces=namespace)
if result:
return result[0]
else:
raise KeyError('%s does not seem to be present in the XML.' %
element_name)
TIME_FORMAT = "%Y-%m-%dT%H:%M:%S.987Z"
# Template container for user's credentials when requesting a bearer token.
USERNAME_TOKEN_TEMPLATE = """\
<ns2:UsernameToken xmlns:ns2="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd">
<ns2:Username>%(_username)s</ns2:Username>
<ns2:Password>%(_password)s</ns2:Password>
</ns2:UsernameToken>"""
# Template containing the anchor to the signature.
USE_KEY_TEMPLATE = """\
<UseKey Sig="%(_signature_id)s"/>"""
# The follwoing template is used to create a timestamp for the various messages.
# The timestamp is used to indicate the duration of the request itself.
TIMESTAMP_TEMPLATE = """\
<ns3:Timestamp xmlns:ns3="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd" ns3:Id="%(_timestamp_id)s">
<ns3:Created>%(_created)s</ns3:Created><ns3:Expires>%(_request_expires)s</ns3:Expires></ns3:Timestamp>"""
# The following template is used to construct the token requests to the STS.
REQUEST_TEMPLATE = """\
<SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/">
<SOAP-ENV:Header>
<ns6:Security xmlns="http://docs.oasis-open.org/ws-sx/ws-trust/200512"
xmlns:ns2="http://www.w3.org/2005/08/addressing"
xmlns:ns3="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd"
xmlns:ns6="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd">
%(_timestamp)s
%(_security_token)s
</ns6:Security>
</SOAP-ENV:Header>
<SOAP-ENV:Body xmlns:wsu="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd" wsu:Id="%(_request_id)s">
<RequestSecurityToken xmlns="http://docs.oasis-open.org/ws-sx/ws-trust/200512"
xmlns:ns2="http://www.w3.org/2005/08/addressing"
xmlns:ns3="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd"
xmlns:ns6="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd">
<TokenType>urn:oasis:names:tc:SAML:2.0:assertion</TokenType>
<RequestType>http://docs.oasis-open.org/ws-sx/ws-trust/200512/Issue</RequestType>
<Lifetime>
<ns3:Created>%(_created)s</ns3:Created>
<ns3:Expires>%(_expires)s</ns3:Expires>
</Lifetime>
<Renewing Allow="%(_renewable)s" OK="%(_renewable)s"/>
<Delegatable>%(_delegatable)s</Delegatable>
<KeyType>%(_key_type)s</KeyType>
<SignatureAlgorithm>http://www.w3.org/2001/04/xmldsig-more#rsa-sha256</SignatureAlgorithm>%(_use_key)s</RequestSecurityToken>
</SOAP-ENV:Body>
</SOAP-ENV:Envelope>"""