Repository: matrix-org/synapse

Issue:
Support importing avatars from SSO identity provider
It would be nice to (optionally?) transfer the account picture/avatar of a user created through OpenID Connect (OIDC) to the Synapse user account.  I'm using google as my provider. Their account pictures is in the `picture` attribute and is a url to the image.


Discussion:
Indeed it would. I thought we had an issue open to track this, but I can't find it :)
It looks like this would only be about calling [set_avatar_url](https://github.com/matrix-org/synapse/blob/f7baffd8ece67c96fac6cd17d50c4aba92f323c5/synapse/handlers/profile.py#L227) from [complete_sso_login_request](https://github.com/matrix-org/synapse/blob/7fbf42499d92ec3c9a05d9f36ec5fecd1ab1f18c/synapse/handlers/sso.py#L486), and map the [picture claim](https://openid.net/specs/openid-connect-core-1_0.html#StandardClaims) in [JinjaOidcMappingProvider](https://github.com/matrix-org/synapse/blob/fe1daad67237c2154a3d8d8cdf6c603f0d33682e/synapse/handlers/oidc.py#L1214). Have I missed something?
> It looks like this would only be about calling [set_avatar_url](https://github.com/matrix-org/synapse/blob/f7baffd8ece67c96fac6cd17d50c4aba92f323c5/synapse/handlers/profile.py#L227) from [complete_sso_login_request](https://github.com/matrix-org/synapse/blob/7fbf42499d92ec3c9a05d9f36ec5fecd1ab1f18c/synapse/handlers/sso.py#L486), and map the [picture claim](https://openid.net/specs/openid-connect-core-1_0.html#StandardClaims) in [JinjaOidcMappingProvider](https://github.com/matrix-org/synapse/blob/fe1daad67237c2154a3d8d8cdf6c603f0d33682e/synapse/handlers/oidc.py#L1214). Have I missed something?

I think that's most of it, I believe avatar URLs need to be mxc URLs though so you might need to store the image first.

Resolving patch:
diff --git a/synapse/handlers/oidc.py b/synapse/handlers/oidc.py
--- a/synapse/handlers/oidc.py
+++ b/synapse/handlers/oidc.py
@@ -1435,6 +1435,7 @@ class UserAttributeDict(TypedDict):
     localpart: Optional[str]
     confirm_localpart: bool
     display_name: Optional[str]
+    picture: Optional[str]  # may be omitted by older `OidcMappingProviders`
     emails: List[str]
 
 
@@ -1520,6 +1521,7 @@ def jinja_finalize(thing: Any) -> Any:
 @attr.s(slots=True, frozen=True, auto_attribs=True)
 class JinjaOidcMappingConfig:
     subject_claim: str
+    picture_claim: str
     localpart_template: Optional[Template]
     display_name_template: Optional[Template]
     email_template: Optional[Template]
@@ -1539,6 +1541,7 @@ def __init__(self, config: JinjaOidcMappingConfig):
     @staticmethod
     def parse_config(config: dict) -> JinjaOidcMappingConfig:
         subject_claim = config.get("subject_claim", "sub")
+        picture_claim = config.get("picture_claim", "picture")
 
         def parse_template_config(option_name: str) -> Optional[Template]:
             if option_name not in config:
@@ -1572,6 +1575,7 @@ def parse_template_config(option_name: str) -> Optional[Template]:
 
         return JinjaOidcMappingConfig(
             subject_claim=subject_claim,
+            picture_claim=picture_claim,
             localpart_template=localpart_template,
             display_name_template=display_name_template,
             email_template=email_template,
@@ -1611,10 +1615,13 @@ def render_template_field(template: Optional[Template]) -> Optional[str]:
         if email:
             emails.append(email)
 
+        picture = userinfo.get("picture")
+
         return UserAttributeDict(
             localpart=localpart,
             display_name=display_name,
             emails=emails,
+            picture=picture,
             confirm_localpart=self._config.confirm_localpart,
         )
 
diff --git a/synapse/handlers/sso.py b/synapse/handlers/sso.py
--- a/synapse/handlers/sso.py
+++ b/synapse/handlers/sso.py
@@ -12,6 +12,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import abc
+import hashlib
+import io
 import logging
 from typing import (
     TYPE_CHECKING,
@@ -138,6 +140,7 @@ class UserAttributes:
     localpart: Optional[str]
     confirm_localpart: bool = False
     display_name: Optional[str] = None
+    picture: Optional[str] = None
     emails: Collection[str] = attr.Factory(list)
 
 
@@ -196,6 +199,10 @@ def __init__(self, hs: "HomeServer"):
         self._error_template = hs.config.sso.sso_error_template
         self._bad_user_template = hs.config.sso.sso_auth_bad_user_template
         self._profile_handler = hs.get_profile_handler()
+        self._media_repo = (
+            hs.get_media_repository() if hs.config.media.can_load_media_repo else None
+        )
+        self._http_client = hs.get_proxied_blacklisted_http_client()
 
         # The following template is shown after a successful user interactive
         # authentication session. It tells the user they can close the window.
@@ -495,6 +502,8 @@ async def complete_sso_login_request(
                         await self._profile_handler.set_displayname(
                             user_id_obj, requester, attributes.display_name, True
                         )
+                if attributes.picture:
+                    await self.set_avatar(user_id, attributes.picture)
 
         await self._auth_handler.complete_sso_login(
             user_id,
@@ -703,8 +712,110 @@ async def _register_mapped_user(
         await self._store.record_user_external_id(
             auth_provider_id, remote_user_id, registered_user_id
         )
+
+        # Set avatar, if available
+        if attributes.picture:
+            await self.set_avatar(registered_user_id, attributes.picture)
+
         return registered_user_id
 
+    async def set_avatar(self, user_id: str, picture_https_url: str) -> bool:
+        """Set avatar of the user.
+
+        This downloads the image file from the URL provided, stores that in
+        the media repository and then sets the avatar on the user's profile.
+
+        It can detect if the same image is being saved again and bails early by storing
+        the hash of the file in the `upload_name` of the avatar image.
+
+        Currently, it only supports server configurations which run the media repository
+        within the same process.
+
+        It silently fails and logs a warning by raising an exception and catching it
+        internally if:
+         * it is unable to fetch the image itself (non 200 status code) or
+         * the image supplied is bigger than max allowed size or
+         * the image type is not one of the allowed image types.
+
+        Args:
+            user_id: matrix user ID in the form @localpart:domain as a string.
+
+            picture_https_url: HTTPS url for the picture image file.
+
+        Returns: `True` if the user's avatar has been successfully set to the image at
+            `picture_https_url`.
+        """
+        if self._media_repo is None:
+            logger.info(
+                "failed to set user avatar because out-of-process media repositories "
+                "are not supported yet "
+            )
+            return False
+
+        try:
+            uid = UserID.from_string(user_id)
+
+            def is_allowed_mime_type(content_type: str) -> bool:
+                if (
+                    self._profile_handler.allowed_avatar_mimetypes
+                    and content_type
+                    not in self._profile_handler.allowed_avatar_mimetypes
+                ):
+                    return False
+                return True
+
+            # download picture, enforcing size limit & mime type check
+            picture = io.BytesIO()
+
+            content_length, headers, uri, code = await self._http_client.get_file(
+                url=picture_https_url,
+                output_stream=picture,
+                max_size=self._profile_handler.max_avatar_size,
+                is_allowed_content_type=is_allowed_mime_type,
+            )
+
+            if code != 200:
+                raise Exception(
+                    "GET request to download sso avatar image returned {}".format(code)
+                )
+
+            # upload name includes hash of the image file's content so that we can
+            # easily check if it requires an update or not, the next time user logs in
+            upload_name = "sso_avatar_" + hashlib.sha256(picture.read()).hexdigest()
+
+            # bail if user already has the same avatar
+            profile = await self._profile_handler.get_profile(user_id)
+            if profile["avatar_url"] is not None:
+                server_name = profile["avatar_url"].split("/")[-2]
+                media_id = profile["avatar_url"].split("/")[-1]
+                if server_name == self._server_name:
+                    media = await self._media_repo.store.get_local_media(media_id)
+                    if media is not None and upload_name == media["upload_name"]:
+                        logger.info("skipping saving the user avatar")
+                        return True
+
+            # store it in media repository
+            avatar_mxc_url = await self._media_repo.create_content(
+                media_type=headers[b"Content-Type"][0].decode("utf-8"),
+                upload_name=upload_name,
+                content=picture,
+                content_length=content_length,
+                auth_user=uid,
+            )
+
+            # save it as user avatar
+            await self._profile_handler.set_avatar_url(
+                uid,
+                create_requester(uid),
+                str(avatar_mxc_url),
+            )
+
+            logger.info("successfully saved the user avatar")
+            return True
+        except Exception:
+            logger.warning("failed to save the user avatar")
+            return False
+
     async def complete_sso_ui_auth_request(
         self,
         auth_provider_id: str,


Test patch:
diff --git a/tests/handlers/test_sso.py b/tests/handlers/test_sso.py
new file mode 100644
--- /dev/null
+++ b/tests/handlers/test_sso.py
@@ -0,0 +1,145 @@
+# 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 http import HTTPStatus
+from typing import BinaryIO, Callable, Dict, List, Optional, Tuple
+from unittest.mock import Mock
+
+from twisted.test.proto_helpers import MemoryReactor
+from twisted.web.http_headers import Headers
+
+from synapse.api.errors import Codes, SynapseError
+from synapse.http.client import RawHeaders
+from synapse.server import HomeServer
+from synapse.util import Clock
+
+from tests import unittest
+from tests.test_utils import SMALL_PNG, FakeResponse
+
+
+class TestSSOHandler(unittest.HomeserverTestCase):
+    def make_homeserver(self, reactor: MemoryReactor, clock: Clock) -> HomeServer:
+        self.http_client = Mock(spec=["get_file"])
+        self.http_client.get_file.side_effect = mock_get_file
+        self.http_client.user_agent = b"Synapse Test"
+        hs = self.setup_test_homeserver(
+            proxied_blacklisted_http_client=self.http_client
+        )
+        return hs
+
+    async def test_set_avatar(self) -> None:
+        """Tests successfully setting the avatar of a newly created user"""
+        handler = self.hs.get_sso_handler()
+
+        # Create a new user to set avatar for
+        reg_handler = self.hs.get_registration_handler()
+        user_id = self.get_success(reg_handler.register_user(approved=True))
+
+        self.assertTrue(
+            self.get_success(handler.set_avatar(user_id, "http://my.server/me.png"))
+        )
+
+        # Ensure avatar is set on this newly created user,
+        # so no need to compare for the exact image
+        profile_handler = self.hs.get_profile_handler()
+        profile = self.get_success(profile_handler.get_profile(user_id))
+        self.assertIsNot(profile["avatar_url"], None)
+
+    @unittest.override_config({"max_avatar_size": 1})
+    async def test_set_avatar_too_big_image(self) -> None:
+        """Tests that saving an avatar fails when it is too big"""
+        handler = self.hs.get_sso_handler()
+
+        # any random user works since image check is supposed to fail
+        user_id = "@sso-user:test"
+
+        self.assertFalse(
+            self.get_success(handler.set_avatar(user_id, "http://my.server/me.png"))
+        )
+
+    @unittest.override_config({"allowed_avatar_mimetypes": ["image/jpeg"]})
+    async def test_set_avatar_incorrect_mime_type(self) -> None:
+        """Tests that saving an avatar fails when its mime type is not allowed"""
+        handler = self.hs.get_sso_handler()
+
+        # any random user works since image check is supposed to fail
+        user_id = "@sso-user:test"
+
+        self.assertFalse(
+            self.get_success(handler.set_avatar(user_id, "http://my.server/me.png"))
+        )
+
+    async def test_skip_saving_avatar_when_not_changed(self) -> None:
+        """Tests whether saving of avatar correctly skips if the avatar hasn't
+        changed"""
+        handler = self.hs.get_sso_handler()
+
+        # Create a new user to set avatar for
+        reg_handler = self.hs.get_registration_handler()
+        user_id = self.get_success(reg_handler.register_user(approved=True))
+
+        # set avatar for the first time, should be a success
+        self.assertTrue(
+            self.get_success(handler.set_avatar(user_id, "http://my.server/me.png"))
+        )
+
+        # get avatar picture for comparison after another attempt
+        profile_handler = self.hs.get_profile_handler()
+        profile = self.get_success(profile_handler.get_profile(user_id))
+        url_to_match = profile["avatar_url"]
+
+        # set same avatar for the second time, should be a success
+        self.assertTrue(
+            self.get_success(handler.set_avatar(user_id, "http://my.server/me.png"))
+        )
+
+        # compare avatar picture's url from previous step
+        profile = self.get_success(profile_handler.get_profile(user_id))
+        self.assertEqual(profile["avatar_url"], url_to_match)
+
+
+async def mock_get_file(
+    url: str,
+    output_stream: BinaryIO,
+    max_size: Optional[int] = None,
+    headers: Optional[RawHeaders] = None,
+    is_allowed_content_type: Optional[Callable[[str], bool]] = None,
+) -> Tuple[int, Dict[bytes, List[bytes]], str, int]:
+
+    fake_response = FakeResponse(code=404)
+    if url == "http://my.server/me.png":
+        fake_response = FakeResponse(
+            code=200,
+            headers=Headers(
+                {"Content-Type": ["image/png"], "Content-Length": [str(len(SMALL_PNG))]}
+            ),
+            body=SMALL_PNG,
+        )
+
+    if max_size is not None and max_size < len(SMALL_PNG):
+        raise SynapseError(
+            HTTPStatus.BAD_GATEWAY,
+            "Requested file is too large > %r bytes" % (max_size,),
+            Codes.TOO_LARGE,
+        )
+
+    if is_allowed_content_type and not is_allowed_content_type("image/png"):
+        raise SynapseError(
+            HTTPStatus.BAD_GATEWAY,
+            (
+                "Requested file's content type not allowed for this operation: %s"
+                % "image/png"
+            ),
+        )
+
+    output_stream.write(fake_response.body)
+
+    return len(SMALL_PNG), {b"Content-Type": [b"image/png"]}, "", 200