nathan-v/aws_okta_keyman

#
# Credits: This code was copied from
# https://github.com/ThoughtWorksInc/aws_role_credentials
#
# Copyright (c) 2015, Peter Gillard-Moss
# All rights reserved.
# Permission to use, copy, modify, and/or distribute this software for any
# purpose with or without fee is hereby granted, provided that the above
# copyright notice and this permission notice appear in all copies.
# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
"""AWS SAML assertion parser."""
import base64
import xml.etree.ElementTree as ET


class SamlAssertion:
    """Handle the AWS SAML assertion."""

    def __init__(self, assertion):
        self.assertion = assertion

    @staticmethod
    def split_roles(roles):
        """Split out the roles from the string response."""
        return [(y.strip()) for y in roles.text.split(",")]

    @staticmethod
    def sort_roles(roles):
        """Sort and return the AWS roles."""
        return sorted(roles, key=lambda role: "saml-provider" in role)

    def roles(self):
        """Extract role information from the assertion."""
        attributes = ET.fromstring(self.assertion).iter(
            "{urn:oasis:names:tc:SAML:2.0:assertion}Attribute",
        )

        name = "https://aws.amazon.com/SAML/Attributes/Role"
        roles_attributes = [x for x in attributes if x.get("Name") == name]

        roles_values = [
            (x.iter("{urn:oasis:names:tc:SAML:2.0:assertion}AttributeValue"))
            for x in roles_attributes
        ]

        return [
            (dict(zip(["role", "principle"], self.sort_roles(self.split_roles(x)))))
            for x in roles_values[0]
        ]

    def encode(self):
        """b64 encoding handler."""
        return base64.b64encode(self.assertion).decode()