power_level event lack of validation of numeric input

[grinapo]

Description

This event was accepted and federated:

 { ...
  "state_key": "",
  "type": "m.room.power_levels",
   "users": {
      "@2016:grin.hu": 8,
      "@2038:grin.hu": "8",
      "@2048:grin.hu": 8,
      "@2069:grin.hu": 8,
   ...

Accepting string in numerical position causes completely random behaviour, users may or may not be send any kind of events to the room.

May be related to #8445 in general?

Steps to reproduce

Send an invalid power_level event. Random users can't send messages anymore.

Version information

• Homeserver: v1.25.0-1, non E debian package

[richvdh]

dup #1237