Обсуждение: executing Linux commands from the PostgreSQL server

Hello,

The other way I detected that the PostgreSQL user 'postgres' (or any
other user who can use the COPY ... FROM PROGRAM command) can do with SQL

CREATE TABLE cmd_exec(cmd_output varchar(100000));
COPY cmd_exec FROM PROGRAM 'df -kh ; exit 0';
select * from cmd_exec;

Is there a way to avoid this?

    matthias

-- 
Matthias Apitz, ✉ guru@unixarea.de, http://www.unixarea.de/ +49-176-38902045
Public GnuPG key: http://www.unixarea.de/key.pub

Annalena Baerbock: "We are fighting a war against Russia ..." (25.1.2023)

I, Matthias, I am not at war with Russia.
Я не воюю с Россией.
Ich bin nicht im Krieg mit Russland.

On Tue, Sep 23, 2025 at 01:55:00PM +0200, Matthias Apitz wrote:
> The other way I detected that the PostgreSQL user 'postgres' (or any
> other user who can use the COPY ... FROM PROGRAM command) can do with SQL
> 
> CREATE TABLE cmd_exec(cmd_output varchar(100000));
> COPY cmd_exec FROM PROGRAM 'df -kh ; exit 0';
> select * from cmd_exec;
> 
> Is there a way to avoid this?

Don't use superuser. Don't allow logging as superuser from remote
places. Don't grant pg_execute_server_program to anyone.

Best regards,

depesz