libeis: check incoming objects' version for correctness

If the server sends a protocol version higher than we support, fail.

src/libeis-client.c

@@ -323,6 +323,7 @@ client_msg_sync(struct eis_connection *connection, object_id_t new_id, uint32_t
 	struct eis_client *client = eis_connection_get_client(connection);
 
 	DISCONNECT_IF_INVALID_ID(client, new_id);
+	DISCONNECT_IF_INVALID_VERSION(client, ei_connection, new_id, version);
 
 	struct eis_callback *callback = eis_callback_new(client, new_id, version);
 	log_debug(eis_client_get_context(client) , "object %#" PRIx64 ": connection sync done", new_id);

src/libeis-private.h

@@ -169,3 +169,14 @@ eis_log_msg_va(struct eis *eis,
 	eis_log_msg((T_), EIS_LOG_PRIORITY_ERROR, __FILE__, __LINE__, __func__, "🪳  libeis bug:  " __VA_ARGS__)
 #define log_bug_client(T_, ...) \
 	eis_log_msg((T_), EIS_LOG_PRIORITY_ERROR, __FILE__, __LINE__, __func__, "🪲  Bug: " __VA_ARGS__)
+
+#define DISCONNECT_IF_INVALID_VERSION(eis_client_, intf_, id_, version_) do { \
+	struct eis_client *_client = (eis_client_); \
+	uint32_t _version = (version_); \
+	uint64_t _id = (id_); \
+	if (_client->interface_versions.intf_ < _version) { \
+		struct eis *_eis = eis_client_get_context(_client); \
+		log_bug(_eis, "Received invalid version %u for object id %#" PRIx64 ". Disconnecting", _version, _id); \
+		return brei_result_new(EIS_CONNECTION_DISCONNECT_REASON_PROTOCOL, "Received invalid version %u for object id %#" PRIx64 ".", _version, _id); \
+	} \
+} while(0)

test/test_protocol.py

@@ -947,6 +947,44 @@ class TestEiProtocol:
         ), status.explanation
         assert status.explanation is not None
 
+    def test_invalid_callback_version(self, eis):
+        """
+        Expect to get disconnected if we allocate a client object outside the agreed version range.
+        Right now only callbacks are client-created, so that's all we can test here.
+        """
+        ei = eis.ei
+        ei.dispatch()
+
+        ei.init_default_sender_connection()
+        ei.dispatch()
+        ei.wait_for_connection()
+
+        @attr.s
+        class Status:
+            disconnected: bool = attr.ib(default=False)
+            reason: int = attr.ib(default=0)
+            explanation: Optional[str] = attr.ib(default=None)
+
+        status = Status()
+
+        def on_disconnected(connection, last_serial, reason, explanation):
+            status.disconnected = True
+            status.reason = reason
+            status.explanation = explanation
+
+        ei.connection.connect("Disconnected", on_disconnected)
+
+        cb = EiCallback.create(0x100, VERSION_V(100))
+        ei.context.register(cb)
+        ei.send(ei.connection.Sync(cb.object_id, cb.version))
+
+        ei.wait_for(lambda: status.disconnected)
+        assert status.disconnected
+        assert (
+            status.reason == EiConnection.EiDisconnectReason.PROTOCOL
+        ), status.explanation
+        assert status.explanation is not None
+
     @pytest.mark.parametrize(
         "wanted_interface",
         (