Little thing about permanent members of the security council are not allowed to provide the Secretary General.
Not true. There are no restrictions on who can be Secretary General. There is a tradition that the Secretary come from smaller countries, but there is no prohibition aganst anything.
a General Assembly
a Security Council
an Economic and Social Council
a Trusteeship Council
an International Court of Justice
and a Secretariat.
The Secretariat is an organ that has no restrictions on it.
-PJ