Use Pydantic to validate /devices endpoints

changelog.d/14054.feature

@@ -0,0 +1 @@
+Improve validation of request bodies for the [Device Management](https://spec.matrix.org/v1.4/client-server-api/#device-management) and [MSC2697 Device Dehyrdation](https:/matrix-org/matrix-spec-proposals/pull/2697) client-server API endpoints.

synapse/rest/client/devices.py

@@ -14,18 +14,21 @@
 # limitations under the License.
 
 import logging
-from typing import TYPE_CHECKING, Tuple
+from typing import TYPE_CHECKING, List, Optional, Tuple
+
+from pydantic import Extra, StrictStr
 
 from synapse.api import errors
 from synapse.api.errors import NotFoundError
 from synapse.http.server import HttpServer
 from synapse.http.servlet import (
  RestServlet,
- assert_params_in_dict,
- parse_json_object_from_request,
+ parse_and_validate_json_object_from_request,
 )
 from synapse.http.site import SynapseRequest
 from synapse.rest.client._base import client_patterns, interactive_auth_handler
+from synapse.rest.client.models import AuthenticationData
+from synapse.rest.models import RequestBodyModel
 from synapse.types import JsonDict
 
 if TYPE_CHECKING:
@@ -80,35 +83,37 @@ def __init__(self, hs: "HomeServer"):
  self.device_handler = hs.get_device_handler()
  self.auth_handler = hs.get_auth_handler()
 
+ class PostBody(RequestBodyModel):
+ auth: Optional[AuthenticationData]
+ devices: List[StrictStr]
+
  @interactive_auth_handler
  async def on_POST(self, request: SynapseRequest) -> Tuple[int, JsonDict]:
  requester = await self.auth.get_user_by_req(request)
 
  try:
- body = parse_json_object_from_request(request)
+ body = parse_and_validate_json_object_from_request(request, self.PostBody)
  except errors.SynapseError as e:
  if e.errcode == errors.Codes.NOT_JSON:
- # DELETE
+ # TODO: Can/should we remove this fallback now?
  # deal with older clients which didn't pass a JSON dict
  # the same as those that pass an empty dict
- body = {}
+ body = self.PostBody.parse_obj({})
  else:
  raise e
 
- assert_params_in_dict(body, ["devices"])
-
  await self.auth_handler.validate_user_via_ui_auth(
  requester,
  request,
- body,
+ body.dict(exclude_unset=True),
  "remove device(s) from your account",
  # Users might call this multiple times in a row while cleaning up
  # devices, allow a single UI auth session to be re-used.
  can_skip_ui_auth=True,
  )
 
  await self.device_handler.delete_devices(
- requester.user.to_string(), body["devices"]
+ requester.user.to_string(), body.devices
  )
  return 200, {}
 
@@ -147,27 +152,31 @@ async def on_GET(
 
  return 200, device
 
+ class DeleteBody(RequestBodyModel):
+ auth: Optional[AuthenticationData]
+
  @interactive_auth_handler
  async def on_DELETE(
  self, request: SynapseRequest, device_id: str
  ) -> Tuple[int, JsonDict]:
  requester = await self.auth.get_user_by_req(request)
 
  try:
- body = parse_json_object_from_request(request)
+ body = parse_and_validate_json_object_from_request(request, self.DeleteBody)
 
  except errors.SynapseError as e:
  if e.errcode == errors.Codes.NOT_JSON:
+ # TODO: can/should we remove this fallback now?
  # deal with older clients which didn't pass a JSON dict
  # the same as those that pass an empty dict
- body = {}
+ body = self.DeleteBody.parse_obj({})
  else:
  raise
 
  await self.auth_handler.validate_user_via_ui_auth(
  requester,
  request,
- body,
+ body.dict(exclude_unset=True),
  "remove a device from your account",
  # Users might call this multiple times in a row while cleaning up
  # devices, allow a single UI auth session to be re-used.
@@ -179,18 +188,33 @@ async def on_DELETE(
  )
  return 200, {}
 
+ class PutBody(RequestBodyModel):
+ display_name: Optional[StrictStr]
+
  async def on_PUT(
  self, request: SynapseRequest, device_id: str
  ) -> Tuple[int, JsonDict]:
  requester = await self.auth.get_user_by_req(request, allow_guest=True)
 
- body = parse_json_object_from_request(request)
+ body = parse_and_validate_json_object_from_request(request, self.PutBody)
  await self.device_handler.update_device(
- requester.user.to_string(), device_id, body
+ requester.user.to_string(), device_id, body.dict()
  )
  return 200, {}
 
 
+class DehydratedDeviceDataModel(RequestBodyModel):
+ """JSON blob describing a dehydrated device to be stored.
+
+ Expects other freeform fields. Use .dict() to access them.
+ """
+
+ class Config:
+ extra = Extra.allow
+
+ algorithm: StrictStr
+
+
 class DehydratedDeviceServlet(RestServlet):
  """Retrieve or store a dehydrated device.
 
@@ -246,27 +270,19 @@ async def on_GET(self, request: SynapseRequest) -> Tuple[int, JsonDict]:
  else:
  raise errors.NotFoundError("No dehydrated device available")
 
+ class PutBody(RequestBodyModel):
+ device_id: StrictStr
+ device_data: DehydratedDeviceDataModel
+ initial_device_display_name: Optional[StrictStr]
+
  async def on_PUT(self, request: SynapseRequest) -> Tuple[int, JsonDict]:
- submission = parse_json_object_from_request(request)
+ submission = parse_and_validate_json_object_from_request(request, self.PutBody)
  requester = await self.auth.get_user_by_req(request)
 
- if "device_data" not in submission:
- raise errors.SynapseError(
- 400,
- "device_data missing",
- errcode=errors.Codes.MISSING_PARAM,
- )
- elif not isinstance(submission["device_data"], dict):
- raise errors.SynapseError(
- 400,
- "device_data must be an object",
- errcode=errors.Codes.INVALID_PARAM,
- )
-
  device_id = await self.device_handler.store_dehydrated_device(
  requester.user.to_string(),
- submission["device_data"],
- submission.get("initial_device_display_name", None),
+ submission.device_data,
+ submission.initial_device_display_name,
  )
  return 200, {"device_id": device_id}
 
@@ -300,28 +316,18 @@ def __init__(self, hs: "HomeServer"):
  self.auth = hs.get_auth()
  self.device_handler = hs.get_device_handler()
 
+ class PostBody(RequestBodyModel):
+ device_id: StrictStr
+
  async def on_POST(self, request: SynapseRequest) -> Tuple[int, JsonDict]:
  requester = await self.auth.get_user_by_req(request)
 
- submission = parse_json_object_from_request(request)
-
- if "device_id" not in submission:
- raise errors.SynapseError(
- 400,
- "device_id missing",
- errcode=errors.Codes.MISSING_PARAM,
- )
- elif not isinstance(submission["device_id"], str):
- raise errors.SynapseError(
- 400,
- "device_id must be a string",
- errcode=errors.Codes.INVALID_PARAM,
- )
+ submission = parse_and_validate_json_object_from_request(request, self.PostBody)
 
  result = await self.device_handler.rehydrate_device(
  requester.user.to_string(),
  self.auth.get_access_token_from_request(request),
- submission["device_id"],
+ submission.device_id,
  )
 
  return 200, result