Add signing host and keyname to signatures

synapse/api/auth.py

@@ -416,11 +416,15 @@ class Auth(object):
                     key_validity_url
                 )
                 return False
+            for _, signature_block in join_third_party_invite["signatures"].items():
+                for key_name, encoded_signature in signature_block.items():
+                    if not key_name.startswith("ed25519:"):
+                        return False
                     verify_key = nacl.signing.VerifyKey(decode_base64(public_key))
-            encoded_signature = join_third_party_invite["signature"]
                     signature = decode_base64(encoded_signature)
                     verify_key.verify(token, signature)
                     return True
+            return False
         except (KeyError, BadSignatureError,):
             return False
 

synapse/util/third_party_invites.py

@@ -23,7 +23,7 @@ JOIN_KEYS = {
     "token",
     "public_key",
     "key_validity_url",
-    "signature",
+    "signatures",
     "sender",
 }