Re: Support a`--with-copy-program` compile flag - Mailing list pgsql-hackers

From Heikki Linnakangas
Subject Re: Support a`--with-copy-program` compile flag
Date
Msg-id 6ab1546e-5bb9-4408-8495-81373504e3ab@iki.fi
Whole thread Raw
In response to Support a`--with-copy-program` compile flag  (Steve Chavez <steve@supabase.io>)
List pgsql-hackers
On 12/11/2025 20:07, Steve Chavez wrote:
> Hello hackers,
> 
> Postgres provides the `COPY .. TO/FROM PROGRAM` statement. This is 
> dangerous from a security perspective because it allows users to escape 
> from the SQL sandbox and gain shell access on the instance.
> 
> Now there's the `pg_execute_server_program` predefined role to restrict 
> access to `COPY.. TO/FROM PROGRAM` but if somehow a pg user gains 
> superuser privileges then the predefined role is of no use.
> 
> So I wonder if we could remove the possibility of shell access by 
> providing a `--with-copy-program` compile flag.

If you are superuser, there are many other ways you can gain shell 
access. There is no security boundary there.

See e.g. 
https://www.postgresql.org/about/news/cve-2019-9193-not-a-security-vulnerability-1935/

- Heikki




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