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"""Contains classes and functions that are necessary to implement
different bindings.
Bindings normally consists of three parts:
- rules about what to send
- how to package the information
- which protocol to use
"""
import base64
try:
import html
except:
import cgi as html
import logging
import saml2
from saml2.s_utils import deflate_and_base64_encode
from saml2.sigver import REQ_ORDER, RESP_ORDER
from saml2.xmldsig import SIG_ALLOWED_ALG
import six
from six.moves.urllib.parse import urlencode, urlparse
try:
from xml.etree import cElementTree as ElementTree
if ElementTree.VERSION < '1.3.0':
# cElementTree has no support for register_namespace
# neither _namespace_map, thus we sacrify performance
# for correctness
from xml.etree import ElementTree
except ImportError:
try:
import cElementTree as ElementTree
except ImportError:
from elementtree import ElementTree
import defusedxml.ElementTree
logger = logging.getLogger(__name__)
NAMESPACE = "http://schemas.xmlsoap.org/soap/envelope/"
HTML_INPUT_ELEMENT_SPEC = '<input type="{type}" name="{name}" value="{val}"/>'
HTML_FORM_SPEC = """<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
</head>
<body onload="document.forms[0].submit()">
<noscript>
<p>
<strong>Note:</strong>
Since your browser does not support JavaScript,
you must press the Continue button once to proceed.
</p>
</noscript>
<form action="{action}" method="post">
{saml_response_input}
{relay_state_input}
<noscript>
<input type="submit" value="Continue"/>
</noscript>
</form>
</body>
</html>"""
def _html_escape(payload):
return html.escape(payload, quote=True)
def http_form_post_message(message, location, relay_state="",
typ="SAMLRequest", **kwargs):
"""The HTTP POST binding defines a mechanism by which SAML protocol
messages may be transmitted within the base64-encoded content of a
HTML form control.
:param message: The message
:param location: Where the form should be posted to
:param relay_state: for preserving and conveying state information
:return: A tuple containing header information and a HTML message.
"""
if not isinstance(message, six.string_types):
message = str(message)
if not isinstance(message, six.binary_type):
message = message.encode('utf-8')
if typ == "SAMLRequest" or typ == "SAMLResponse":
_msg = base64.b64encode(message)
else:
_msg = message
_msg = _msg.decode('ascii')
saml_response_input = HTML_INPUT_ELEMENT_SPEC.format(
name=_html_escape(typ),
val=_html_escape(_msg),
type='hidden')
relay_state_input = ""
if relay_state:
relay_state_input = HTML_INPUT_ELEMENT_SPEC.format(
name='RelayState',
val=_html_escape(relay_state),
type='hidden')
response = HTML_FORM_SPEC.format(
saml_response_input=saml_response_input,
relay_state_input=relay_state_input,
action=location)
return {"headers": [("Content-type", "text/html")], "data": response}
def http_post_message(message, relay_state="", typ="SAMLRequest", **kwargs):
"""
:param message: The message
:param relay_state: for preserving and conveying state information
:return: A tuple containing header information and a HTML message.
"""
if not isinstance(message, six.string_types):
message = str(message)
if not isinstance(message, six.binary_type):
message = message.encode('utf-8')
if typ == "SAMLRequest" or typ == "SAMLResponse":
_msg = base64.b64encode(message)
else:
_msg = message
_msg = _msg.decode('ascii')
part = {typ: _msg}
if relay_state:
part["RelayState"] = relay_state
return {"headers": [("Content-type", 'application/x-www-form-urlencoded')],
"data": urlencode(part)}
def http_redirect_message(message, location, relay_state="", typ="SAMLRequest",
sigalg='', signer=None, **kwargs):
"""The HTTP Redirect binding defines a mechanism by which SAML protocol
messages can be transmitted within URL parameters.
Messages are encoded for use with this binding using a URL encoding
technique, and transmitted using the HTTP GET method.
The DEFLATE Encoding is used in this function.
:param message: The message
:param location: Where the message should be posted to
:param relay_state: for preserving and conveying state information
:param typ: What type of message it is SAMLRequest/SAMLResponse/SAMLart
:param sigalg: Which algorithm the signature function will use to sign
the message
:param signer: A signature function that can be used to sign the message
:return: A tuple containing header information and a HTML message.
"""
if not isinstance(message, six.string_types):
message = "%s" % (message,)
_order = None
if typ in ["SAMLRequest", "SAMLResponse"]:
if typ == "SAMLRequest":
_order = REQ_ORDER
else:
_order = RESP_ORDER
args = {typ: deflate_and_base64_encode(message)}
elif typ == "SAMLart":
args = {typ: message}
else:
raise Exception("Unknown message type: %s" % typ)
if relay_state:
args["RelayState"] = relay_state
if signer:
# sigalgs, should be one defined in xmldsig
if sigalg not in [long_name for short_name, long_name in SIG_ALLOWED_ALG]:
raise Exception(
"Signature algo not in allowed list: {algo}".format(algo=sigalg)
)
args["SigAlg"] = sigalg
string = "&".join([urlencode({k: args[k]})
for k in _order if k in args]).encode('ascii')
args["Signature"] = base64.b64encode(signer.sign(string))
string = urlencode(args)
else:
string = urlencode(args)
glue_char = "&" if urlparse(location).query else "?"
login_url = glue_char.join([location, string])
headers = [('Location', str(login_url))]
body = []
return {"headers": headers, "data": body}
DUMMY_NAMESPACE = "http://example.org/"
PREFIX = '<?xml version="1.0" encoding="UTF-8"?>'
def make_soap_enveloped_saml_thingy(thingy, header_parts=None):
""" Returns a soap envelope containing a SAML request
as a text string.
:param thingy: The SAML thingy
:return: The SOAP envelope as a string
"""
envelope = ElementTree.Element('')
envelope.tag = '{%s}Envelope' % NAMESPACE
if header_parts:
header = ElementTree.Element('')
header.tag = '{%s}Header' % NAMESPACE
envelope.append(header)
for part in header_parts:
# This doesn't work if the headers are signed
part.become_child_element_of(header)
body = ElementTree.Element('')
body.tag = '{%s}Body' % NAMESPACE
envelope.append(body)
if isinstance(thingy, six.string_types):
# remove the first XML version/encoding line
if thingy[0:5].lower() == '<?xml':
logger.debug("thingy0: %s", thingy)
_part = thingy.split("\n")
thingy = "".join(_part[1:])
thingy = thingy.replace(PREFIX, "")
logger.debug("thingy: %s", thingy)
_child = ElementTree.Element('')
_child.tag = '{%s}FuddleMuddle' % DUMMY_NAMESPACE
body.append(_child)
_str = ElementTree.tostring(envelope, encoding="UTF-8")
if isinstance(_str, six.binary_type):
_str = _str.decode('utf-8')
logger.debug("SOAP precursor: %s", _str)
# find an remove the namespace definition
i = _str.find(DUMMY_NAMESPACE)
j = _str.rfind("xmlns:", 0, i)
cut1 = _str[j:i + len(DUMMY_NAMESPACE) + 1]
_str = _str.replace(cut1, "")
first = _str.find("<%s:FuddleMuddle" % (cut1[6:9],))
last = _str.find(">", first + 14)
cut2 = _str[first:last + 1]
return _str.replace(cut2, thingy)
else:
thingy.become_child_element_of(body)
return ElementTree.tostring(envelope, encoding="UTF-8")
def http_soap_message(message):
return {"headers": [("Content-type", "application/soap+xml")],
"data": make_soap_enveloped_saml_thingy(message)}
def http_paos(message, extra=None):
return {"headers": [("Content-type", "application/soap+xml")],
"data": make_soap_enveloped_saml_thingy(message, extra)}
def parse_soap_enveloped_saml(text, body_class, header_class=None):
"""Parses a SOAP enveloped SAML thing and returns header parts and body
:param text: The SOAP object as XML
:return: header parts and body as saml.samlbase instances
"""
envelope = defusedxml.ElementTree.fromstring(text)
envelope_tag = "{%s}Envelope" % NAMESPACE
if envelope.tag != envelope_tag:
raise ValueError(
"Invalid envelope tag '{invalid}' should be '{valid}'".format(
invalid=envelope.tag, valid=envelope_tag
)
)
# print(len(envelope))
body = None
header = {}
for part in envelope:
# print(">",part.tag)
if part.tag == '{%s}Body' % NAMESPACE:
for sub in part:
try:
body = saml2.create_class_from_element_tree(
body_class, sub)
except Exception:
raise Exception(
"Wrong body type (%s) in SOAP envelope" % sub.tag)
elif part.tag == '{%s}Header' % NAMESPACE:
if not header_class:
raise Exception("Header where I didn't expect one")
# print("--- HEADER ---")
for sub in part:
# print(">>",sub.tag)
for klass in header_class:
# print("?{%s}%s" % (klass.c_namespace,klass.c_tag))
if sub.tag == "{%s}%s" % (klass.c_namespace, klass.c_tag):
header[sub.tag] = \
saml2.create_class_from_element_tree(klass, sub)
break
return body, header
# -----------------------------------------------------------------------------
PACKING = {
saml2.BINDING_HTTP_REDIRECT: http_redirect_message,
saml2.BINDING_HTTP_POST: http_form_post_message,
}
def packager(identifier):
try:
return PACKING[identifier]
except KeyError:
raise Exception("Unknown binding type: %s" % identifier)
def factory(binding, message, location, relay_state="", typ="SAMLRequest",
**kwargs):
return PACKING[binding](message, location, relay_state, typ, **kwargs)
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