| From: | jian he <jian(dot)universality(at)gmail(dot)com> |
|---|---|
| To: | Feike Steenbergen <feikesteenbergen(at)gmail(dot)com> |
| Cc: | PostgreSQL mailing lists <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: pg18: Virtual generated columns are not (yet) safe when superuser selects from them |
| Date: | 2025-05-24 13:42:31 |
| Message-ID: | CACJufxEcDR7S2Kyv0QG0GSkoHMtJ3Y=pM8dqXLhOTcCdBhAA+Q@mail.gmail.com |
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| Lists: | pgsql-hackers |
On Sat, May 24, 2025 at 2:39 PM Feike Steenbergen
<feikesteenbergen(at)gmail(dot)com> wrote:
>
> The loophole is this:
>
> - the generated virtual column can use a user-defined function
> - when running SELECT against that column by a superuser
> the function is called within the context of a superuser
> - this in turn allows the regular user to run any code within
> the context of superuser
sorry, I am not fully sure what this means.
a minimum sql reproducer would be great.
you may check virtual generated column function privilege regress tests on
https://git.postgresql.org/cgit/postgresql.git/tree/src/test/regress/sql/generated_virtual.sql#n284
(from line 284 to line 303)
also see [1].
PostgreSQL grants EXECUTE privilege for functions and procedures to
PUBLIC *by default* when the objects are created.
[1]: https://www.postgresql.org/docs/current/ddl-priv.html#PRIVILEGES-SUMMARY-TABLE
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