Block delegation escalation of privilege

Forbids doing the following with either a trust
  or oauth based token:
  creating a trust
  approving a request_token
  listing request tokens

Change-Id: I1528f9dd003f5e03cbc50b78e1b32dbbf85ffcc2
Closes-Bug:  1324592

keystone/common/authorization.py

@@ -67,7 +67,7 @@ def is_v3_token(token):
 
 
 def v3_token_to_auth_context(token):
-    creds = {}
+    creds = {'is_delegated_auth': False}
     token_data = token['token']
     try:
         creds['user_id'] = token_data['user']['id']
@@ -87,11 +87,31 @@ def v3_token_to_auth_context(token):
     creds['group_ids'] = [
         g['id'] for g in token_data['user'].get(federation.FEDERATION, {}).get(
             'groups', [])]
+
+    trust = token_data.get('OS-TRUST:trust')
+    if trust is None:
+        creds['trust_id'] = None
+        creds['trustor_id'] = None
+        creds['trustee_id'] = None
+    else:
+        creds['trust_id'] = trust['id']
+        creds['trustor_id'] = trust['trustor_user']['id']
+        creds['trustee_id'] = trust['trustee_user']['id']
+        creds['is_delegated_auth'] = True
+
+    oauth1 = token_data.get('OS-OAUTH1')
+    if oauth1 is None:
+        creds['consumer_id'] = None
+        creds['access_token_id'] = None
+    else:
+        creds['consumer_id'] = oauth1['consumer_id']
+        creds['access_token_id'] = oauth1['access_token_id']
+        creds['is_delegated_auth'] = True
     return creds
 
 
 def v2_token_to_auth_context(token):
-    creds = {}
+    creds = {'is_delegated_auth': False}
     token_data = token['access']
     try:
         creds['user_id'] = token_data['user']['id']
@@ -105,6 +125,18 @@ def v2_token_to_auth_context(token):
     if 'roles' in token_data['user']:
         creds['roles'] = [role['name'] for
                           role in token_data['user']['roles']]
+
+    trust = token_data.get('trust')
+    if trust is None:
+        creds['trust_id'] = None
+        creds['trustor_id'] = None
+        creds['trustee_id'] = None
+    else:
+        creds['trust_id'] = trust.get('id')
+        creds['trustor_id'] = trust.get('trustor_id')
+        creds['trustee_id'] = trust.get('trustee_id')
+        creds['is_delegated_auth'] = True
+
     return creds
 
 

keystone/contrib/oauth1/controllers.py

@@ -95,6 +95,12 @@ class AccessTokenCrudV3(controller.V3Controller):
 
     @controller.protected()
     def list_access_tokens(self, context, user_id):
+        auth_context = context.get('environment',
+                                   {}).get('KEYSTONE_AUTH_CONTEXT', {})
+        if auth_context.get('is_delegated_auth'):
+            raise exception.Forbidden(
+                _('Cannot list request tokens'
+                  ' with a token issued via delegation.'))
         refs = self.oauth_api.list_access_tokens(user_id)
         formatted_refs = ([self._format_token_entity(context, x)
                            for x in refs])
@@ -310,6 +316,12 @@ class OAuthControllerV3(controller.V3Controller):
         there is not another easy way to make sure the user knows which roles
         are being requested before authorizing.
         """
+        auth_context = context.get('environment',
+                                   {}).get('KEYSTONE_AUTH_CONTEXT', {})
+        if auth_context.get('is_delegated_auth'):
+            raise exception.Forbidden(
+                _('Cannot authorize a request token'
+                  ' with a token issued via delegation.'))
 
         req_token = self.oauth_api.get_request_token(request_token_id)
 

keystone/tests/test_v3_auth.py

@@ -2777,6 +2777,42 @@ class TestTrustAuth(TestAuthInfo):
         self.assertEqual(r.result['token']['project']['name'],
                          self.project['name'])
 
+    def test_impersonation_token_cannot_create_new_trust(self):
+        ref = self.new_trust_ref(
+            trustor_user_id=self.user_id,
+            trustee_user_id=self.trustee_user_id,
+            project_id=self.project_id,
+            impersonation=True,
+            expires=dict(minutes=1),
+            role_ids=[self.role_id])
+        del ref['id']
+
+        r = self.post('/OS-TRUST/trusts', body={'trust': ref})
+        trust = self.assertValidTrustResponse(r)
+
+        auth_data = self.build_authentication_request(
+            user_id=self.trustee_user['id'],
+            password=self.trustee_user['password'],
+            trust_id=trust['id'])
+        r = self.post('/auth/tokens', body=auth_data)
+
+        trust_token = r.headers['X-Subject-Token']
+
+        # Build second trust
+        ref = self.new_trust_ref(
+            trustor_user_id=self.user_id,
+            trustee_user_id=self.trustee_user_id,
+            project_id=self.project_id,
+            impersonation=True,
+            expires=dict(minutes=1),
+            role_ids=[self.role_id])
+        del ref['id']
+
+        self.post('/OS-TRUST/trusts',
+                  body={'trust': ref},
+                  token=trust_token,
+                  expected_status=403)
+
     def assertTrustTokensRevoked(self, trust_id):
         revocation_response = self.get('/OS-REVOKE/events',
                                        expected_status=200)

keystone/tests/test_v3_oauth1.py

@@ -13,6 +13,8 @@
 # under the License.
 
 import copy
+import os
+import tempfile
 import uuid
 
 from six.moves import urllib
@@ -26,6 +28,7 @@ from keystone.contrib.oauth1 import controllers
 from keystone import exception
 from keystone.openstack.common.db.sqlalchemy import migration
 from keystone.openstack.common import importutils
+from keystone.openstack.common import jsonutils
 from keystone.tests import test_v3
 
 
@@ -486,6 +489,100 @@ class AuthTokenTests(OAuthFlowTests):
         self.assertRaises(exception.TokenNotFound, self.token_api.get_token,
                           self.keystone_token_id)
 
+    def _create_trust_get_token(self):
+        ref = self.new_trust_ref(
+            trustor_user_id=self.user_id,
+            trustee_user_id=self.user_id,
+            project_id=self.project_id,
+            impersonation=True,
+            expires=dict(minutes=1),
+            role_ids=[self.role_id])
+        del ref['id']
+
+        r = self.post('/OS-TRUST/trusts', body={'trust': ref})
+        trust = self.assertValidTrustResponse(r)
+
+        auth_data = self.build_authentication_request(
+            user_id=self.user['id'],
+            password=self.user['password'],
+            trust_id=trust['id'])
+        r = self.post('/auth/tokens', body=auth_data)
+
+        trust_token = r.headers['X-Subject-Token']
+        return trust_token
+
+    def _approve_request_token_url(self):
+        consumer = self._create_single_consumer()
+        consumer_id = consumer['id']
+        consumer_secret = consumer['secret']
+        self.consumer = {'key': consumer_id, 'secret': consumer_secret}
+        self.assertIsNotNone(self.consumer['secret'])
+
+        url, headers = self._create_request_token(self.consumer,
+                                                  self.project_id)
+        content = self.post(url, headers=headers)
+        credentials = urllib.parse.parse_qs(content.result)
+        request_key = credentials['oauth_token'][0]
+        request_secret = credentials['oauth_token_secret'][0]
+        self.request_token = oauth1.Token(request_key, request_secret)
+        self.assertIsNotNone(self.request_token.key)
+
+        url = self._authorize_request_token(request_key)
+
+        return url
+
+    def test_oauth_token_cannot_create_new_trust(self):
+        self.test_oauth_flow()
+        ref = self.new_trust_ref(
+            trustor_user_id=self.user_id,
+            trustee_user_id=self.user_id,
+            project_id=self.project_id,
+            impersonation=True,
+            expires=dict(minutes=1),
+            role_ids=[self.role_id])
+        del ref['id']
+
+        self.post('/OS-TRUST/trusts',
+                  body={'trust': ref},
+                  token=self.keystone_token_id,
+                  expected_status=403)
+
+    def test_oauth_token_cannot_authorize_request_token(self):
+        self.test_oauth_flow()
+        url = self._approve_request_token_url()
+        body = {'roles': [{'id': self.role_id}]}
+        self.put(url, body=body, token=self.keystone_token_id,
+                 expected_status=403)
+
+    def test_oauth_token_cannot_list_request_tokens(self):
+        self._set_policy({"identity:list_access_tokens": [],
+                          "identity:create_consumer": [],
+                          "identity:authorize_request_token": []})
+        self.test_oauth_flow()
+        url = '/users/%s/OS-OAUTH1/access_tokens' % self.user_id
+        self.get(url, token=self.keystone_token_id,
+                 expected_status=403)
+
+    def _set_policy(self, new_policy):
+        _unused, self.tmpfilename = tempfile.mkstemp()
+        self.config_fixture.config(policy_file=self.tmpfilename)
+        with open(self.tmpfilename, "w") as policyfile:
+            policyfile.write(jsonutils.dumps(new_policy))
+        self.addCleanup(os.remove, self.tmpfilename)
+
+    def test_trust_token_cannot_authorize_request_token(self):
+        trust_token = self._create_trust_get_token()
+        url = self._approve_request_token_url()
+        body = {'roles': [{'id': self.role_id}]}
+        self.put(url, body=body, token=trust_token, expected_status=403)
+
+    def test_trust_token_cannot_list_request_tokens(self):
+        self._set_policy({"identity:list_access_tokens": [],
+                          "identity:create_trust": []})
+        trust_token = self._create_trust_get_token()
+        url = '/users/%s/OS-OAUTH1/access_tokens' % self.user_id
+        self.get(url, token=trust_token, expected_status=403)
+
 
 class MaliciousOAuth1Tests(OAuth1Tests):
 

keystone/trust/controllers.py

@@ -132,6 +132,15 @@ class TrustV3(controller.V3Controller):
 
         # TODO(ayoung): instead of raising ValidationError on the first
         # problem, return a collection of all the problems.
+
+        # Explicitly prevent a trust token from creating a new trust.
+        auth_context = context.get('environment',
+                                   {}).get('KEYSTONE_AUTH_CONTEXT', {})
+        if auth_context.get('is_delegated_auth'):
+            raise exception.Forbidden(
+                _('Cannot create a trust'
+                  ' with a token issued via delegation.'))
+
         if not trust:
             raise exception.ValidationError(attribute='trust',
                                             target='request')