diff --git a/HISTORY.md b/HISTORY.md
index e498068ae..9d39efafe 100644
--- a/HISTORY.md
+++ b/HISTORY.md
@@ -1,3 +1,9 @@
+v0.3.1 (2014-6-16)
+-----------
+* Bugfix: lua mongo driver . Hold reply string before decode bson data.
+* More check in bson decoding.
+* Use big-endian for encoding bson objectid.
+
 v0.3.0 (2014-6-2)
 -----------
 * Add cluster support
diff --git a/Makefile b/Makefile
index 9c84351d4..3c5fd4465 100644
--- a/Makefile
+++ b/Makefile
@@ -66,7 +66,7 @@ $(CSERVICE_PATH) :
 
 define CSERVICE_TEMP
   $$(CSERVICE_PATH)/$(1).so : service-src/service_$(1).c | $$(CSERVICE_PATH)
-	$(CC) $$(CFLAGS) $$(SHARED) $$< -o $$@ -Iskynet-src
+	$$(CC) $$(CFLAGS) $$(SHARED) $$< -o $$@ -Iskynet-src
 endef
 
 $(foreach v, $(CSERVICE), $(eval $(call CSERVICE_TEMP,$(v))))
diff --git a/lualib-src/lua-bson.c b/lualib-src/lua-bson.c
index ca73bae03..07fb77e29 100644
--- a/lualib-src/lua-bson.c
+++ b/lualib-src/lua-bson.c
@@ -68,6 +68,13 @@ struct bson_reader {
 	int size;
 };
 
+static inline int32_t
+get_length(const uint8_t * data) {
+	const uint8_t * b = (const uint8_t *)data;
+	int32_t len = b[0] | b[1]<<8 | b[2]<<16 | b[3]<<24;
+	return len;
+}
+
 static inline void
 bson_destroy(struct bson *b) {
 	if (b->ptr != b->buffer) {
@@ -644,7 +651,7 @@ static int
 lmakeindex(lua_State *L) {
 	int32_t *bson = luaL_checkudata(L,1,"bson");
 	const uint8_t * start = (const uint8_t *)bson;
-	struct bson_reader br = { start+4, *bson - 5 };
+	struct bson_reader br = { start+4, get_length(start) - 5 };
 	lua_newtable(L);
 
 	for (;;) {
@@ -820,7 +827,9 @@ ldecode(lua_State *L) {
 	if (data == NULL) {
 		return 0;
 	}
-	struct bson_reader br = { (const uint8_t *)data , *data };
+	const uint8_t * b = (const uint8_t *)data;
+	int32_t len = get_length(b);
+	struct bson_reader br = { b , len };
 
 	unpack_dict(L, &br, false);
 
@@ -1140,14 +1149,14 @@ lobjectid(lua_State *L) {
 		}
 	} else {
 		time_t ti = time(NULL);
-		oid[2] = ti & 0xff;
-		oid[3] = (ti>>8) & 0xff;
-		oid[4] = (ti>>16) & 0xff;
-		oid[5] = (ti>>24) & 0xff;
+		oid[2] = (ti>>24) & 0xff;
+		oid[3] = (ti>>16) & 0xff;
+		oid[4] = (ti>>8) & 0xff;
+		oid[5] = ti & 0xff;
 		memcpy(oid+6 , oid_header, 5);
-		oid[11] = oid_counter & 0xff; 
+		oid[11] = (oid_counter>>16) & 0xff; 
 		oid[12] = (oid_counter>>8) & 0xff; 
-		oid[13] = (oid_counter>>16) & 0xff; 
+		oid[13] = oid_counter & 0xff; 
 		++oid_counter;
 	}
 	lua_pushlstring( L, (const char *)oid, 14);
diff --git a/lualib-src/lua-mongo.c b/lualib-src/lua-mongo.c
index a0d312fd5..3e4666dc6 100644
--- a/lualib-src/lua-mongo.c
+++ b/lualib-src/lua-mongo.c
@@ -260,6 +260,13 @@ op_reply(lua_State *L) {
 			lua_pushnil(L);
 			lua_rawseti(L, 2, i);
 		}
+	} else {
+		if (sz >= 4) {
+			sz -= get_length((document)doc);
+		}
+	}
+	if (sz != 0) {
+		return luaL_error(L, "Invalid result bson document");
 	}
 	lua_pushboolean(L,1);
 	lua_pushinteger(L, id);
diff --git a/lualib/mongo.lua b/lualib/mongo.lua
index 7b1c6f69f..f9eece357 100644
--- a/lualib/mongo.lua
+++ b/lualib/mongo.lua
@@ -98,7 +98,7 @@ function mongo.client( conf )
 		host = obj.host,
 		port = obj.port,
 		response = dispatch_reply,
-		auth = mongo_auth(conf),
+		auth = mongo_auth(obj),
 	}
 	setmetatable(obj, client_meta)
 	obj.__sock:connect(true)	-- try connect only once
@@ -167,7 +167,9 @@ function mongo_db:runCommand(cmd,cmd_v,...)
 		bson_cmd = bson_encode_order(cmd,cmd_v,...)
 	end
 	local pack = driver.query(request_id, 0, self.__cmd, 0, 1, bson_cmd)
-	local doc = sock:request(pack, request_id).document
+	-- we must hold req (req.data), because req.document is a lightuserdata, it's a pointer to the string (req.data)
+	local req = sock:request(pack, request_id)
+	local doc = req.document
 	return bson_decode(doc)
 end
 
@@ -224,7 +226,9 @@ function mongo_collection:findOne(query, selector)
 	local request_id = conn:genId()
 	local sock = conn.__sock
 	local pack = driver.query(request_id, 0, self.full_name, 0, 1, query and bson_encode(query) or empty_bson, selector and bson_encode(selector))
-	local doc = sock:request(pack, request_id).document
+	-- we must hold req (req.data), because req.document is a lightuserdata, it's a pointer to the string (req.data)
+	local req = sock:request(pack, request_id)
+	local doc = req.document
 	return bson_decode(doc)
 end