Tom Lane 91d7c0bfdd Require superuser to install a non-built-in selectivity estimator.
Selectivity estimators come in two flavors: those that make specific
assumptions about the data types they are working with, and those
that don't.  Most of the built-in estimators are of the latter kind
and are meant to be safely attachable to any operator.  If the
operator does not behave as the estimator expects, you might get a
poor estimate, but it won't crash.

However, estimators that do make datatype assumptions can malfunction
if they are attached to the wrong operator, since then the data they
get from pg_statistic may not be of the type they expect.  This can
rise to the level of a security problem, even permitting arbitrary
code execution by a user who has the ability to create SQL objects.

To close this hole, establish a rule that built-in estimators are
required to protect themselves against being called on the wrong type
of data.  It does not seem practical however to expect estimators in
extensions to reach a similar level of security, at least not in the
near term.  Therefore, also establish a rule that superuser privilege
is required to attach a non-built-in estimator to an operator.
We expect that this restriction will have little negative impact on
extensions, since estimators generally have to be written in C and
thus superuser privilege is required to create them in the first
place.

This commit changes the privilege checks in CREATE/ALTER OPERATOR
to enforce the rule about superuser privilege, and fixes a couple
of built-in estimators that were making datatype assumptions without
sufficiently checking that they're valid.

Reported-by: Daniel Firer as part of zeroday.cloud
Author: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Noah Misch <noah@leadboat.com>
Security: CVE-2026-2004
Backpatch-through: 14
2026-02-09 10:07:31 -05:00
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2020-02-10 20:47:50 +01:00
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PostgreSQL Database Management System
=====================================

This directory contains the source code distribution of the PostgreSQL
database management system.

PostgreSQL is an advanced object-relational database management system
that supports an extended subset of the SQL standard, including
transactions, foreign keys, subqueries, triggers, user-defined types
and functions.  This distribution also contains C language bindings.

PostgreSQL has many language interfaces, many of which are listed here:

	https://www.postgresql.org/download/

See the file INSTALL for instructions on how to build and install
PostgreSQL.  That file also lists supported operating systems and
hardware platforms and contains information regarding any other
software packages that are required to build or run the PostgreSQL
system.  Copyright and license information can be found in the
file COPYRIGHT.  A comprehensive documentation set is included in this
distribution; it can be read as described in the installation
instructions.

The latest version of this software may be obtained at
https://www.postgresql.org/download/.  For more information look at our
web site located at https://www.postgresql.org/.
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