Security bug: password length check should be in check_user, not check_connections(),

otherwise COM_CHANGE_USER is unprotected and can be used for both privilege escalation and buffer overrun

sql/sql_parse.cc

@@ -109,6 +109,8 @@ static bool check_user(THD *thd,enum_server_command command, const char *user,
   NET *net= &thd->net;
   thd->db=0;
 
+  if (passwd[0] && strlen(passwd) != SCRAMBLE_LENGTH)
+    return 1;
   if (!(thd->user = my_strdup(user, MYF(0))))
   {
     send_error(net,ER_OUT_OF_RESOURCES);
@@ -458,8 +460,6 @@ check_connections(THD *thd)
   char *user=   (char*) net->read_pos+5;
   char *passwd= strend(user)+1;
   char *db=0;
-  if (passwd[0] && strlen(passwd) != SCRAMBLE_LENGTH)
-    return ER_HANDSHAKE_ERROR;
   if (thd->client_capabilities & CLIENT_CONNECT_WITH_DB)
     db=strend(passwd)+1;
   if (thd->client_capabilities & CLIENT_INTERACTIVE)