[Minor] Lua_text: Sanitize span length

diff --git a/src/lua/lua_text.c b/src/lua/lua_text.c
index de8fa9b93c17e90743021e978076261a9a9fd143..307b2823fa5433993a95d05c684729283e8ad0b6 100644 (file)
--- a/src/lua/lua_text.c
+++ b/src/lua/lua_text.c
@@ -460,7 +460,8 @@ lua_text_span (lua_State *L)
                if (len == -1) {
                        len = t->len - (start - 1);
                }
-               else if (len > (t->len - (start - 1))) {
+
+               if (len < 0 || (len > (t->len - (start - 1)))) {
                        return luaL_error (L, "invalid length");
                }