Add validation of app cred access rules

This commit adds a validation step in the auth_token middleware to check
for the presence of an access_rules attribute in an application
credential token and to validate the request against the permissions
granted for that token. During token validation it sends a header to
keystone to indicate that it is capable of validating these access
rules, and not providing this header for a token like this would result
in the token failing validation. This disregards access rules for a
service request made by a service on behalf of a user, such as nova
making a request to glance, because such a request is not under the
control of the user and is not expected to be explicitly allowed in the
access rules.

bp whitelist-extension-for-app-creds

Depends-On: https://review.opendev.org/670377

Change-Id: I185e0541d5df538d74edadf9976b3034a2470c88

7 files changed, 365 insertions, 2 deletions

diff --git a/keystonemiddleware/auth_token/__init__.py b/keystonemiddleware/auth_token/__init__.py
index dcf166b..b29b63a 100644
--- a/keystonemiddleware/auth_token/__init__.py
+++ b/keystonemiddleware/auth_token/__init__.py
@@ -218,6 +218,7 @@ object is stored.
 """
 
 import copy
+import re
 
 from keystoneauth1 import access
 from keystoneauth1 import adapter
@@ -277,6 +278,26 @@ def list_opts():
     return [(g, copy.deepcopy(o)) for g, o in AUTH_TOKEN_OPTS]
 
 
+def _path_matches(request_path, path_pattern):
+    # The fnmatch module doesn't provide the ability to match * versus **,
+    # so convert to regex.
+    token_regex = (r'(?P<tag>{[^}]*})|'  # {tag} # nosec
+                   '(?P<wild>\*(?=$|[^\*]))|'  # *
+                   '(?P<rec_wild>\*\*)|'  # **
+                   '(?P<literal>[^{}\*])')  # anything else
+    path_regex = ''
+    for match in re.finditer(token_regex, path_pattern):
+        token = match.groupdict()
+        if token['tag'] or token['wild']:
+            path_regex += '[^\/]+'
+        if token['rec_wild']:
+            path_regex += '.*'
+        if token['literal']:
+            path_regex += token['literal']
+    path_regex = r'^%s$' % path_regex
+    return re.match(path_regex, request_path)
+
+
 class _BIND_MODE(object):
     DISABLED = 'disabled'
     PERMISSIVE = 'permissive'
@@ -301,13 +322,15 @@ class BaseAuthProtocol(object):
                  log=_LOG,
                  enforce_token_bind=_BIND_MODE.PERMISSIVE,
                  service_token_roles=None,
-                 service_token_roles_required=False):
+                 service_token_roles_required=False,
+                 service_type=None):
         self.log = log
         self._app = app
         self._enforce_token_bind = enforce_token_bind
         self._service_token_roles = set(service_token_roles or [])
         self._service_token_roles_required = service_token_roles_required
         self._service_token_warning_emitted = False
+        self._service_type = service_type
 
     @webob.dec.wsgify(RequestClass=_request._AuthTokenRequest)
     def __call__(self, req):
@@ -388,6 +411,8 @@ class BaseAuthProtocol(object):
                     allow_expired=allow_expired)
                 self._validate_token(user_auth_ref,
                                      allow_expired=allow_expired)
+                if user_auth_ref.version != 'v2.0':
+                    self.validate_allowed_request(request, data['token'])
                 if not request.service_token:
                     self._confirm_token_bind(user_auth_ref, request)
             except ksm_exceptions.InvalidToken:
@@ -516,6 +541,53 @@ class BaseAuthProtocol(object):
                     {'bind_type': bind_type, 'identifier': identifier})
                 self._invalid_user_token()
 
+    def validate_allowed_request(self, request, token):
+        self.log.debug("Validating token access rules against request")
+        app_cred = token.get('application_credential')
+        if not app_cred:
+            return
+        access_rules = app_cred.get('access_rules')
+        if access_rules is None:
+            return
+        if hasattr(self, '_conf'):
+            my_service_type = self._conf.get('service_type')
+        else:
+            my_service_type = self._service_type
+        if not my_service_type:
+            self.log.warning('Cannot validate request with restricted'
+                             ' access rules. Set service_type in'
+                             ' [keystone_authtoken] to allow access rule'
+                             ' validation.')
+            raise ksm_exceptions.InvalidToken(_('Token authorization failed'))
+        # token can always be validated regardless of access rules
+        if (my_service_type == 'identity' and
+                request.method == 'GET' and
+                request.path.endswith('/v3/auth/tokens')):
+            return
+        catalog = token['catalog']
+        # validate service type is in catalog
+        catalog_svcs = [s for s in catalog if s['type'] == my_service_type]
+        if len(catalog_svcs) == 0:
+            self.log.warning('Cannot validate request with restricted'
+                             ' access rules. service_type in'
+                             ' [keystone_authtoken] is not a valid service'
+                             ' type in the catalog.')
+            raise ksm_exceptions.InvalidToken(_('Token authorization failed'))
+        if request.service_token:
+            # The request may not match an allowed request, but the presence
+            # of the service token indicates this is a chain of requests and
+            # hence this request was not user-facing
+            return
+        for access_rule in access_rules:
+            method = access_rule['method']
+            path = access_rule['path']
+            service = access_rule['service']
+            if request.method == method and \
+                    service == my_service_type and \
+                    _path_matches(request.path, path):
+                return
+        raise ksm_exceptions.InvalidToken(_('Token authorization failed'))
+
 
 class AuthProtocol(BaseAuthProtocol):
     """Middleware that handles authenticating client calls."""
diff --git a/keystonemiddleware/auth_token/_identity.py b/keystonemiddleware/auth_token/_identity.py
index 4c10521..3967c23 100644
--- a/keystonemiddleware/auth_token/_identity.py
+++ b/keystonemiddleware/auth_token/_identity.py
@@ -21,6 +21,8 @@ from keystonemiddleware.auth_token import _auth
 from keystonemiddleware.auth_token import _exceptions as ksm_exceptions
 from keystonemiddleware.i18n import _
 
+ACCESS_RULES_SUPPORT = '1'
+
 
 class _RequestStrategy(object):
 
@@ -69,7 +71,8 @@ class _V3RequestStrategy(_RequestStrategy):
         auth_ref = self._client.tokens.validate(
             token,
             include_catalog=self._include_service_catalog,
-            allow_expired=allow_expired)
+            allow_expired=allow_expired,
+            access_rules_support=ACCESS_RULES_SUPPORT)
 
         if not auth_ref:
             msg = _('Failed to fetch token data from identity server')
diff --git a/keystonemiddleware/auth_token/_opts.py b/keystonemiddleware/auth_token/_opts.py
index b551407..f16d3f8 100644
--- a/keystonemiddleware/auth_token/_opts.py
+++ b/keystonemiddleware/auth_token/_opts.py
@@ -178,6 +178,10 @@ _OPTS = [
                 ' service tokens pass that don\'t pass the service_token_roles'
                 ' check as valid. Setting this true will become the default'
                 ' in a future release and should be enabled if possible.'),
+    cfg.StrOpt('service_type',
+               help='The name or type of the service as it appears in the'
+               ' service catalog. This is used to validate tokens that have'
+               ' restricted access rules.'),
 ]
 
 
diff --git a/keystonemiddleware/tests/unit/auth_token/test_auth_token_middleware.py b/keystonemiddleware/tests/unit/auth_token/test_auth_token_middleware.py
index 04e605c..9fd0328 100644
--- a/keystonemiddleware/tests/unit/auth_token/test_auth_token_middleware.py
+++ b/keystonemiddleware/tests/unit/auth_token/test_auth_token_middleware.py
@@ -1413,6 +1413,110 @@ class v3AuthTokenMiddlewareTest(BaseAuthTokenMiddlewareTest,
         e = self.requests_mock.request_history[3].qs.get('allow_expired')
         self.assertIsNone(e)
 
+    def test_app_cred_token_without_access_rules(self):
+        self.set_middleware(conf={'service_type': 'compute'})
+        token = self.examples.v3_APP_CRED_TOKEN
+        token_data = self.examples.TOKEN_RESPONSES[token]
+        resp = self.call_middleware(headers={'X-Auth-Token': token})
+        self.assertEqual(FakeApp.SUCCESS, resp.body)
+        token_auth = resp.request.environ['keystone.token_auth']
+        self.assertEqual(token_data.application_credential_id,
+                         token_auth.user.application_credential_id)
+
+    def test_app_cred_access_rules_token(self):
+        self.set_middleware(conf={'service_type': 'compute'})
+        token = self.examples.v3_APP_CRED_ACCESS_RULES
+        token_data = self.examples.TOKEN_RESPONSES[token]
+        resp = self.call_middleware(headers={'X-Auth-Token': token},
+                                    expected_status=200,
+                                    method='GET', path='/v2.1/servers')
+        token_auth = resp.request.environ['keystone.token_auth']
+        self.assertEqual(token_data.application_credential_id,
+                         token_auth.user.application_credential_id)
+        self.assertEqual(token_data.application_credential_access_rules,
+                         token_auth.user.application_credential_access_rules)
+        resp = self.call_middleware(headers={'X-Auth-Token': token},
+                                    expected_status=401,
+                                    method='GET',
+                                    path='/v2.1/servers/someuuid')
+        token_auth = resp.request.environ['keystone.token_auth']
+        self.assertEqual(token_data.application_credential_id,
+                         token_auth.user.application_credential_id)
+        self.assertEqual(token_data.application_credential_access_rules,
+                         token_auth.user.application_credential_access_rules)
+
+    def test_app_cred_access_rules_service_request(self):
+        self.set_middleware(conf={'service_type': 'image'})
+        token = self.examples.v3_APP_CRED_ACCESS_RULES
+        headers = {'X-Auth-Token': token}
+        self.call_middleware(headers=headers,
+                             expected_status=401,
+                             method='GET', path='/v2/images')
+        service_token = self.examples.v3_UUID_SERVICE_TOKEN_DEFAULT
+        headers['X-Service-Token'] = service_token
+        self.call_middleware(headers=headers,
+                             expected_status=200,
+                             method='GET', path='/v2/images')
+
+    def test_app_cred_no_access_rules_token(self):
+        self.set_middleware(conf={'service_type': 'compute'})
+        token = self.examples.v3_APP_CRED_EMPTY_ACCESS_RULES
+        self.call_middleware(headers={'X-Auth-Token': token},
+                             expected_status=401,
+                             method='GET', path='/v2.1/servers')
+        service_token = self.examples.v3_UUID_SERVICE_TOKEN_DEFAULT
+        headers = {
+            'X-Auth-Token': token,
+            'X-Service-Token': service_token
+        }
+        self.call_middleware(headers=headers, expected_status=401,
+                             method='GET', path='/v2.1/servers')
+
+    def test_app_cred_matching_rules(self):
+        self.set_middleware(conf={'service_type': 'compute'})
+        token = self.examples.v3_APP_CRED_MATCHING_RULES
+        self.call_middleware(headers={'X-Auth-Token': token},
+                             expected_status=200,
+                             method='GET', path='/v2.1/servers/foobar')
+        self.call_middleware(headers={'X-Auth-Token': token},
+                             expected_status=401,
+                             method='GET', path='/v2.1/servers/foobar/barfoo')
+        self.set_middleware(conf={'service_type': 'image'})
+        self.call_middleware(headers={'X-Auth-Token': token},
+                             expected_status=200,
+                             method='GET', path='/v2/images/foobar')
+        self.call_middleware(headers={'X-Auth-Token': token},
+                             expected_status=401,
+                             method='GET', path='/v2/images/foobar/barfoo')
+        self.set_middleware(conf={'service_type': 'identity'})
+        self.call_middleware(headers={'X-Auth-Token': token},
+                             expected_status=200,
+                             method='GET',
+                             path='/v3/projects/123/users/456/roles/member')
+        self.set_middleware(conf={'service_type': 'block-storage'})
+        self.call_middleware(headers={'X-Auth-Token': token},
+                             expected_status=200,
+                             method='GET', path='/v3/123/types/456')
+        self.call_middleware(headers={'X-Auth-Token': token},
+                             expected_status=401,
+                             method='GET', path='/v3/123/types')
+        self.call_middleware(headers={'X-Auth-Token': token},
+                             expected_status=401,
+                             method='GET', path='/v2/123/types/456')
+        self.set_middleware(conf={'service_type': 'object-store'})
+        self.call_middleware(headers={'X-Auth-Token': token},
+                             expected_status=200,
+                             method='GET', path='/v1/1/2/3')
+        self.call_middleware(headers={'X-Auth-Token': token},
+                             expected_status=401,
+                             method='GET', path='/v1/1/2')
+        self.call_middleware(headers={'X-Auth-Token': token},
+                             expected_status=401,
+                             method='GET', path='/v2/1/2')
+        self.call_middleware(headers={'X-Auth-Token': token},
+                             expected_status=401,
+                             method='GET', path='/info')
+
 
 class DelayedAuthTests(BaseAuthTokenMiddlewareTest):
 
diff --git a/keystonemiddleware/tests/unit/client_fixtures.py b/keystonemiddleware/tests/unit/client_fixtures.py
index a807054..27ba482 100644
--- a/keystonemiddleware/tests/unit/client_fixtures.py
+++ b/keystonemiddleware/tests/unit/client_fixtures.py
@@ -64,6 +64,11 @@ class Examples(fixtures.Fixture):
         self.v3_UUID_SERVICE_TOKEN_BIND = 'be705e4426d0449a89e35ae21c380a05'
         self.v3_NOT_IS_ADMIN_PROJECT = uuid.uuid4().hex
 
+        self.v3_APP_CRED_TOKEN = '6f506fa9641448bbaecbd12dd30678a9'
+        self.v3_APP_CRED_ACCESS_RULES = 'c417747898c44629b08791f2579e40a5'
+        self.v3_APP_CRED_EMPTY_ACCESS_RULES = 'c75905c307f04fdd9979126582d7aae'
+        self.v3_APP_CRED_MATCHING_RULES = 'ad49decc7106489d95ca9ed874b6cb66'
+
         # JSON responses keyed by token ID
         self.TOKEN_RESPONSES = {}
 
@@ -86,6 +91,8 @@ class Examples(fixtures.Fixture):
         SERVICE_ROLE_NAME1 = 'service'
         SERVICE_ROLE_NAME2 = 'service_role2'
 
+        APP_CRED_ID = 'app_cred_id1'
+
         self.SERVICE_TYPE = 'identity'
         self.UNVERSIONED_SERVICE_URL = 'https://keystone.example.com:1234/'
         self.SERVICE_URL = self.UNVERSIONED_SERVICE_URL + 'v2.0'
@@ -293,6 +300,123 @@ class Examples(fixtures.Fixture):
         svc.add_endpoint('public', self.SERVICE_URL)
         self.TOKEN_RESPONSES[self.v3_NOT_IS_ADMIN_PROJECT] = token
 
+        # Application credential token
+        token = fixture.V3Token(user_id=USER_ID,
+                                user_name=USER_NAME,
+                                user_domain_id=DOMAIN_ID,
+                                user_domain_name=DOMAIN_NAME,
+                                project_id=PROJECT_ID,
+                                project_name=PROJECT_NAME,
+                                project_domain_id=DOMAIN_ID,
+                                project_domain_name=DOMAIN_NAME,
+                                application_credential_id=APP_CRED_ID)
+        token.add_role(name=ROLE_NAME1)
+        token.add_role(name=ROLE_NAME2)
+        svc = token.add_service(self.SERVICE_TYPE)
+        svc.add_endpoint('public', self.SERVICE_URL)
+        svc = token.add_service('compute')
+        svc.add_endpoint('public', 'https://nova.openstack.example.org/v2.1')
+        self.TOKEN_RESPONSES[self.v3_APP_CRED_TOKEN] = token
+
+        # Application credential with access_rules token
+        access_rules = [{
+            'path': '/v2.1/servers',
+            'method': 'GET',
+            'service': 'compute'
+        }]
+        token = fixture.V3Token(
+            user_id=USER_ID,
+            user_name=USER_NAME,
+            user_domain_id=DOMAIN_ID,
+            user_domain_name=DOMAIN_NAME,
+            project_id=PROJECT_ID,
+            project_name=PROJECT_NAME,
+            project_domain_id=DOMAIN_ID,
+            project_domain_name=DOMAIN_NAME,
+            application_credential_id=APP_CRED_ID,
+            application_credential_access_rules=access_rules)
+        token.add_role(name=ROLE_NAME1)
+        token.add_role(name=ROLE_NAME2)
+        svc = token.add_service(self.SERVICE_TYPE)
+        svc.add_endpoint('public', self.SERVICE_URL)
+        svc = token.add_service('compute')
+        svc.add_endpoint('public', 'https://nova.openstack.example.org')
+        svc = token.add_service('image')
+        svc.add_endpoint('public', 'https://glance.openstack.example.org')
+        self.TOKEN_RESPONSES[self.v3_APP_CRED_ACCESS_RULES] = token
+
+        # Application credential with explicitly empty access_rules
+        access_rules = []
+        token = fixture.V3Token(
+            user_id=USER_ID,
+            user_name=USER_NAME,
+            user_domain_id=DOMAIN_ID,
+            user_domain_name=DOMAIN_NAME,
+            project_id=PROJECT_ID,
+            project_name=PROJECT_NAME,
+            project_domain_id=DOMAIN_ID,
+            project_domain_name=DOMAIN_NAME,
+            application_credential_id=APP_CRED_ID,
+            application_credential_access_rules=access_rules)
+        token.add_role(name=ROLE_NAME1)
+        token.add_role(name=ROLE_NAME2)
+        svc = token.add_service(self.SERVICE_TYPE)
+        svc.add_endpoint('public', self.SERVICE_URL)
+        self.TOKEN_RESPONSES[self.v3_APP_CRED_EMPTY_ACCESS_RULES] = token
+
+        # Application credential with matching rules
+        access_rules = [
+            {
+                'path': '/v2.1/servers/{server_id}',
+                'method': 'GET',
+                'service': 'compute'
+            },
+            {
+                'path': '/v2/images/*',
+                'method': 'GET',
+                'service': 'image'
+            },
+            {
+                'path': '**',
+                'method': 'GET',
+                'service': 'identity'
+            },
+            {
+                'path': '/v3/{project_id}/types/{volume_type_id}',
+                'method': 'GET',
+                'service': 'block-storage'
+            },
+            {
+                'path': '/v1/*/*/*',
+                'method': 'GET',
+                'service': 'object-store'
+            }
+        ]
+        token = fixture.V3Token(
+            user_id=USER_ID,
+            user_name=USER_NAME,
+            user_domain_id=DOMAIN_ID,
+            user_domain_name=DOMAIN_NAME,
+            project_id=PROJECT_ID,
+            project_name=PROJECT_NAME,
+            project_domain_id=DOMAIN_ID,
+            project_domain_name=DOMAIN_NAME,
+            application_credential_id=APP_CRED_ID,
+            application_credential_access_rules=access_rules)
+        token.add_role(name=ROLE_NAME1)
+        token.add_role(name=ROLE_NAME2)
+        svc = token.add_service(self.SERVICE_TYPE)
+        svc.add_endpoint('public', self.SERVICE_URL)
+        svc = token.add_service('compute')
+        svc.add_endpoint('public', 'https://nova.openstack.example.org')
+        svc = token.add_service('image')
+        svc.add_endpoint('public', 'https://glance.openstack.example.org')
+        svc = token.add_service('block-storage')
+        svc.add_endpoint('public', 'https://cinder.openstack.example.org')
+        svc = token.add_service('object-store')
+        svc.add_endpoint('public', 'https://swift.openstack.example.org')
+        self.TOKEN_RESPONSES[self.v3_APP_CRED_MATCHING_RULES] = token
+
         self.JSON_TOKEN_RESPONSES = dict([(k, jsonutils.dumps(v)) for k, v in
                                           self.TOKEN_RESPONSES.items()])
 
diff --git a/keystonemiddleware/tests/unit/test_access_rules.py b/keystonemiddleware/tests/unit/test_access_rules.py
new file mode 100644
index 0000000..663b806
--- /dev/null
+++ b/keystonemiddleware/tests/unit/test_access_rules.py
@@ -0,0 +1,54 @@
+# Copyright 2019 SUSE LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+from keystonemiddleware.auth_token import _path_matches
+from keystonemiddleware.tests.unit import utils
+
+
+class TestAccessRules(utils.BaseTestCase):
+
+    def test_path_matches(self):
+        good_matches = [
+            ('/v2/servers', '/v2/servers'),
+            ('/v2/servers/123', '/v2/servers/{server_id}'),
+            ('/v2/servers/123/', '/v2/servers/{server_id}/'),
+            ('/v2/servers/123', '/v2/servers/*'),
+            ('/v2/servers/123/', '/v2/servers/*/'),
+            ('/v2/servers/123', '/v2/servers/**'),
+            ('/v2/servers/123/', '/v2/servers/**'),
+            ('/v2/servers/123/456', '/v2/servers/**'),
+            ('/v2/servers', '**'),
+            ('/v2/servers/', '**'),
+            ('/v2/servers/123', '**'),
+            ('/v2/servers/123/456', '**'),
+            ('/v2/servers/123/volume/456', '**'),
+            ('/v2/servers/123/456', '/v2/*/*/*'),
+            ('/v2/123/servers/466', '/v2/{project_id}/servers/{server_id}'),
+        ]
+        for (request, pattern) in good_matches:
+            self.assertIsNotNone(_path_matches(request, pattern))
+        bad_matches = [
+            ('/v2/servers/someuuid', '/v2/servers'),
+            ('/v2/servers//', '/v2/servers/{server_id}'),
+            ('/v2/servers/123/', '/v2/servers/{server_id}'),
+            ('/v2/servers/123/456', '/v2/servers/{server_id}'),
+            ('/v2/servers/123/456', '/v2/servers/*'),
+            ('/v2/servers', 'v2/servers'),
+            ('/v2/servers/123/456/789', '/v2/*/*/*'),
+            ('/v2/servers/123/', '/v2/*/*/*'),
+            ('/v2/servers/', '/v2/servers/{server_id}'),
+            ('/v2/servers', '/v2/servers/{server_id}'),
+        ]
+        for (request, pattern) in bad_matches:
+            self.assertIsNone(_path_matches(request, pattern))
diff --git a/keystonemiddleware/tests/unit/test_opts.py b/keystonemiddleware/tests/unit/test_opts.py
index 7700d17..799bdd0 100644
--- a/keystonemiddleware/tests/unit/test_opts.py
+++ b/keystonemiddleware/tests/unit/test_opts.py
@@ -69,6 +69,7 @@ class OptsTestCase(utils.TestCase):
             'auth_section',
             'service_token_roles',
             'service_token_roles_required',
+            'service_type',
         ]
         opt_names = [o.name for (g, l) in result_of_old_opts for o in l]
         self.assertThat(opt_names, matchers.HasLength(len(expected_opt_names)))
@@ -113,6 +114,7 @@ class OptsTestCase(utils.TestCase):
             'auth_section',
             'service_token_roles',
             'service_token_roles_required',
+            'service_type',
         ]
         opt_names = [o.name for (g, l) in result for o in l]
         self.assertThat(opt_names, matchers.HasLength(len(expected_opt_names)))