From: Bruce Momjian <bruce@momjian.us>
To: Erki Eessaar <erki.eessaar@taltech.ee>
Cc: pgsql-docs@lists.postgresql.org <pgsql-docs@lists.postgresql.org>
Subject: Re: SQL-standard function bodies and creating SECURITY DEFINER routines securely
Date: Tue, 16 Aug 2022 15:32:36 -0400
Message-ID: <Yvvw1JB/Y12HvAYn@momjian.us> (raw)
In-Reply-To: <AM9PR01MB8268BF5E74E119828251FD34FE409@AM9PR01MB8268.eurprd01.prod.exchangelabs.com>
References: <AM9PR01MB8268BF5E74E119828251FD34FE409@AM9PR01MB8268.eurprd01.prod.exchangelabs.com>
On Sat, Dec 25, 2021 at 02:36:27PM +0000, Erki Eessaar wrote:
>
> Hello
>
> PostgreSQL 14 added the feature: "Allow SQL-language functions and procedures
> to use SQL-standard function bodies."
>
> If I understand correctly, then in this case the system will track
> dependencies between tables and routines that use the tables. Thus, the
> SECURITY DEFINER routines that use the new approach do not require the
> following mitigation, i.e., SET search_path= is not needed. The following part
> of documentation does not mention this.
>
> https://www.postgresql.org/docs/current/sql-createfunction.html#
> SQL-CREATEFUNCTION-SECURITY
>
> [elephant] PostgreSQL: Documentation: 14: CREATE FUNCTION
> Overloading. PostgreSQL allows function overloading; that is, the
> same name can be used for several different functions so long as
> they have distinct input argument types.Whether or not you use it,
> this capability entails security precautions when calling functions
> in databases where some users mistrust other users; see Section
> 10.3.. Two functions are considered the same if they have the same
> ...
> www.postgresql.org
I have written the attached patch to mention this issue about sql_body
functions.
--
Bruce Momjian <bruce@momjian.us> https://momjian.us
EDB https://enterprisedb.com
Indecision is a decision. Inaction is an action. Mark Batterson
Attachments:
[text/x-diff] function.diff (912B, ../Yvvw1JB%2FY12HvAYn@momjian.us/2-function.diff)
download | inline diff:diff --git a/doc/src/sgml/ref/create_function.sgml b/doc/src/sgml/ref/create_function.sgmlindex 7e6d52c7dc..976d4caad6 100644--- a/doc/src/sgml/ref/create_function.sgml+++ b/doc/src/sgml/ref/create_function.sgml@@ -779,7 +779,10 @@ SELECT * FROM dup(42);
<para>
Because a <literal>SECURITY DEFINER</literal> function is executed
with the privileges of the user that owns it, care is needed to
- ensure that the function cannot be misused. For security,+ ensure that the function cannot be misused. This is particularly+ important for non-<replaceable>sql_body</replaceable> functions because+ their function bodies are evaulated at run-time, not creation time.+ For security,
<xref linkend="guc-search-path"/> should be set to exclude any schemas
writable by untrusted users. This prevents
malicious users from creating objects (e.g., tables, functions, and
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-docs@postgresql.org
Cc: bruce@momjian.us, erki.eessaar@taltech.ee, pgsql-docs@lists.postgresql.org
Subject: Re: SQL-standard function bodies and creating SECURITY DEFINER routines securely
In-Reply-To: <Yvvw1JB/Y12HvAYn@momjian.us>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox