use bcrypt.checkpw

in bcrypt 3.1.0 checkpw got introduced (already 2 years ago)
This makes use of that with enhancements which might get introduced
by that

Signed-Off-by: Matthias Kesler <krombel@krombel.de>

synapse/handlers/auth.py

@@ -863,8 +863,10 @@ class AuthHandler(BaseHandler):
         """
 
         def _do_validate_hash():
-            return bcrypt.hashpw(password.encode('utf8') + self.hs.config.password_pepper,
-                                 stored_hash.encode('utf8')) == stored_hash
+            return bcrypt.checkpw(
+                password.encode('utf8') + self.hs.config.password_pepper,
+                stored_hash.encode('utf8')
+            )
 
         if stored_hash:
             return make_deferred_yieldable(threads.deferToThread(_do_validate_hash))

synapse/python_dependencies.py

@@ -31,7 +31,7 @@ REQUIREMENTS = {
     "pyyaml": ["yaml"],
     "pyasn1": ["pyasn1"],
     "daemonize": ["daemonize"],
-    "bcrypt": ["bcrypt"],
+    "bcrypt": ["bcrypt>=3.1.0"],
     "pillow": ["PIL"],
     "pydenticon": ["pydenticon"],
     "ujson": ["ujson"],