Restrict accesses to non-system views and foreign tables during pg_dump.

When pg_dump retrieves the list of database objects and performs the
data dump, there was possibility that objects are replaced with others
of the same name, such as views, and access them. This vulnerability
could result in code execution with superuser privileges during the
pg_dump process.

This issue can arise when dumping data of sequences, foreign
tables (only 13 or later), or tables registered with a WHERE clause in
the extension configuration table.

To address this, pg_dump now utilizes the newly introduced
restrict_nonsystem_relation_kind GUC parameter to restrict the
accesses to non-system views and foreign tables during the dump
process. This new GUC parameter is added to back branches too, but
these changes do not require cluster recreation.

Back-patch to all supported branches.

Reviewed-by: Noah Misch
Security: CVE-2024-7348
Backpatch-through: 12

1 files changed, 8 insertions, 0 deletions

diff --git a/contrib/postgres_fdw/sql/postgres_fdw.sql b/contrib/postgres_fdw/sql/postgres_fdw.sql
index f518e5a67a8..0512c633931 100644
--- a/contrib/postgres_fdw/sql/postgres_fdw.sql
+++ b/contrib/postgres_fdw/sql/postgres_fdw.sql
@@ -326,6 +326,14 @@ DELETE FROM loct_empty;
 ANALYZE ft_empty;
 EXPLAIN (VERBOSE, COSTS OFF) SELECT * FROM ft_empty ORDER BY c1;
 
+-- test restriction on non-system foreign tables.
+SET restrict_nonsystem_relation_kind TO 'foreign-table';
+SELECT * from ft1 where c1 < 1; -- ERROR
+INSERT INTO ft1 (c1) VALUES (1); -- ERROR
+DELETE FROM ft1 WHERE c1 = 1; -- ERROR
+TRUNCATE ft1; -- ERROR
+RESET restrict_nonsystem_relation_kind;
+
 -- ===================================================================
 -- WHERE with remotely-executable conditions
 -- ===================================================================