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-rw-r--r--synapse/handlers/auth.py164
1 files changed, 126 insertions, 38 deletions
diff --git a/synapse/handlers/auth.py b/synapse/handlers/auth.py
index 2f30f183ce..573c9db8a1 100644
--- a/synapse/handlers/auth.py
+++ b/synapse/handlers/auth.py
@@ -17,7 +17,10 @@ from twisted.internet import defer
 
 from ._base import BaseHandler
 from synapse.api.constants import LoginType
-from synapse.api.errors import AuthError, LoginError, Codes, StoreError, SynapseError
+from synapse.api.errors import (
+    AuthError, Codes, InteractiveAuthIncompleteError, LoginError, StoreError,
+    SynapseError,
+)
 from synapse.module_api import ModuleApi
 from synapse.types import UserID
 from synapse.util.async import run_on_reactor
@@ -46,7 +49,6 @@ class AuthHandler(BaseHandler):
         """
         super(AuthHandler, self).__init__(hs)
         self.checkers = {
-            LoginType.PASSWORD: self._check_password_auth,
             LoginType.RECAPTCHA: self._check_recaptcha,
             LoginType.EMAIL_IDENTITY: self._check_email_identity,
             LoginType.MSISDN: self._check_msisdn,
@@ -75,15 +77,76 @@ class AuthHandler(BaseHandler):
         self.macaroon_gen = hs.get_macaroon_generator()
         self._password_enabled = hs.config.password_enabled
 
-        login_types = set()
+        # we keep this as a list despite the O(N^2) implication so that we can
+        # keep PASSWORD first and avoid confusing clients which pick the first
+        # type in the list. (NB that the spec doesn't require us to do so and
+        # clients which favour types that they don't understand over those that
+        # they do are technically broken)
+        login_types = []
         if self._password_enabled:
-            login_types.add(LoginType.PASSWORD)
+            login_types.append(LoginType.PASSWORD)
         for provider in self.password_providers:
             if hasattr(provider, "get_supported_login_types"):
-                login_types.update(
-                    provider.get_supported_login_types().keys()
-                )
-        self._supported_login_types = frozenset(login_types)
+                for t in provider.get_supported_login_types().keys():
+                    if t not in login_types:
+                        login_types.append(t)
+        self._supported_login_types = login_types
+
+    @defer.inlineCallbacks
+    def validate_user_via_ui_auth(self, requester, request_body, clientip):
+        """
+        Checks that the user is who they claim to be, via a UI auth.
+
+        This is used for things like device deletion and password reset where
+        the user already has a valid access token, but we want to double-check
+        that it isn't stolen by re-authenticating them.
+
+        Args:
+            requester (Requester): The user, as given by the access token
+
+            request_body (dict): The body of the request sent by the client
+
+            clientip (str): The IP address of the client.
+
+        Returns:
+            defer.Deferred[dict]: the parameters for this request (which may
+                have been given only in a previous call).
+
+        Raises:
+            InteractiveAuthIncompleteError if the client has not yet completed
+                any of the permitted login flows
+
+            AuthError if the client has completed a login flow, and it gives
+                a different user to `requester`
+        """
+
+        # build a list of supported flows
+        flows = [
+            [login_type] for login_type in self._supported_login_types
+        ]
+
+        result, params, _ = yield self.check_auth(
+            flows, request_body, clientip,
+        )
+
+        # find the completed login type
+        for login_type in self._supported_login_types:
+            if login_type not in result:
+                continue
+
+            user_id = result[login_type]
+            break
+        else:
+            # this can't happen
+            raise Exception(
+                "check_auth returned True but no successful login type",
+            )
+
+        # check that the UI auth matched the access token
+        if user_id != requester.user.to_string():
+            raise AuthError(403, "Invalid auth")
+
+        defer.returnValue(params)
 
     @defer.inlineCallbacks
     def check_auth(self, flows, clientdict, clientip):
@@ -95,26 +158,36 @@ class AuthHandler(BaseHandler):
         session with a map, which maps each auth-type (str) to the relevant
         identity authenticated by that auth-type (mostly str, but for captcha, bool).
 
+        If no auth flows have been completed successfully, raises an
+        InteractiveAuthIncompleteError. To handle this, you can use
+        synapse.rest.client.v2_alpha._base.interactive_auth_handler as a
+        decorator.
+
         Args:
             flows (list): A list of login flows. Each flow is an ordered list of
                           strings representing auth-types. At least one full
                           flow must be completed in order for auth to be successful.
+
             clientdict: The dictionary from the client root level, not the
                         'auth' key: this method prompts for auth if none is sent.
+
             clientip (str): The IP address of the client.
+
         Returns:
-            A tuple of (authed, dict, dict, session_id) where authed is true if
-            the client has successfully completed an auth flow. If it is true
-            the first dict contains the authenticated credentials of each stage.
+            defer.Deferred[dict, dict, str]: a deferred tuple of
+                (creds, params, session_id).
+
+                'creds' contains the authenticated credentials of each stage.
 
-            If authed is false, the first dictionary is the server response to
-            the login request and should be passed back to the client.
+                'params' contains the parameters for this request (which may
+                have been given only in a previous call).
 
-            In either case, the second dict contains the parameters for this
-            request (which may have been given only in a previous call).
+                'session_id' is the ID of this session, either passed in by the
+                client or assigned by this call
 
-            session_id is the ID of this session, either passed in by the client
-            or assigned by the call to check_auth
+        Raises:
+            InteractiveAuthIncompleteError if the client has not yet completed
+                all the stages in any of the permitted flows.
         """
 
         authdict = None
@@ -142,11 +215,8 @@ class AuthHandler(BaseHandler):
             clientdict = session['clientdict']
 
         if not authdict:
-            defer.returnValue(
-                (
-                    False, self._auth_dict_for_flows(flows, session),
-                    clientdict, session['id']
-                )
+            raise InteractiveAuthIncompleteError(
+                self._auth_dict_for_flows(flows, session),
             )
 
         if 'creds' not in session:
@@ -157,14 +227,12 @@ class AuthHandler(BaseHandler):
         errordict = {}
         if 'type' in authdict:
             login_type = authdict['type']
-            if login_type not in self.checkers:
-                raise LoginError(400, "", Codes.UNRECOGNIZED)
             try:
-                result = yield self.checkers[login_type](authdict, clientip)
+                result = yield self._check_auth_dict(authdict, clientip)
                 if result:
                     creds[login_type] = result
                     self._save_session(session)
-            except LoginError, e:
+            except LoginError as e:
                 if login_type == LoginType.EMAIL_IDENTITY:
                     # riot used to have a bug where it would request a new
                     # validation token (thus sending a new email) each time it
@@ -173,7 +241,7 @@ class AuthHandler(BaseHandler):
                     #
                     # Grandfather in the old behaviour for now to avoid
                     # breaking old riot deployments.
-                    raise e
+                    raise
 
                 # this step failed. Merge the error dict into the response
                 # so that the client can have another go.
@@ -190,12 +258,14 @@ class AuthHandler(BaseHandler):
                     "Auth completed with creds: %r. Client dict has keys: %r",
                     creds, clientdict.keys()
                 )
-                defer.returnValue((True, creds, clientdict, session['id']))
+                defer.returnValue((creds, clientdict, session['id']))
 
         ret = self._auth_dict_for_flows(flows, session)
         ret['completed'] = creds.keys()
         ret.update(errordict)
-        defer.returnValue((False, ret, clientdict, session['id']))
+        raise InteractiveAuthIncompleteError(
+            ret,
+        )
 
     @defer.inlineCallbacks
     def add_oob_auth(self, stagetype, authdict, clientip):
@@ -268,17 +338,35 @@ class AuthHandler(BaseHandler):
         return sess.setdefault('serverdict', {}).get(key, default)
 
     @defer.inlineCallbacks
-    def _check_password_auth(self, authdict, _):
-        if "user" not in authdict or "password" not in authdict:
-            raise LoginError(400, "", Codes.MISSING_PARAM)
+    def _check_auth_dict(self, authdict, clientip):
+        """Attempt to validate the auth dict provided by a client
+
+        Args:
+            authdict (object): auth dict provided by the client
+            clientip (str): IP address of the client
+
+        Returns:
+            Deferred: result of the stage verification.
+
+        Raises:
+            StoreError if there was a problem accessing the database
+            SynapseError if there was a problem with the request
+            LoginError if there was an authentication problem.
+        """
+        login_type = authdict['type']
+        checker = self.checkers.get(login_type)
+        if checker is not None:
+            res = yield checker(authdict, clientip)
+            defer.returnValue(res)
+
+        # build a v1-login-style dict out of the authdict and fall back to the
+        # v1 code
+        user_id = authdict.get("user")
 
-        user_id = authdict["user"]
-        password = authdict["password"]
+        if user_id is None:
+            raise SynapseError(400, "", Codes.MISSING_PARAM)
 
-        (canonical_id, callback) = yield self.validate_login(user_id, {
-            "type": LoginType.PASSWORD,
-            "password": password,
-        })
+        (canonical_id, callback) = yield self.validate_login(user_id, authdict)
         defer.returnValue(canonical_id)
 
     @defer.inlineCallbacks