From f52db969440bbbf6c9c46c9c98c1eb7a5619354f Mon Sep 17 00:00:00 2001
From: Tomas Vondra <tomas.vondra@postgresql.org>
Date: Fri, 15 Jan 2021 23:24:19 +0100
Subject: [PATCH] Disallow CREATE STATISTICS on system catalogs
Add a check that CREATE STATISTICS does not add extended statistics on
system catalogs, similarly to indexes etc. It can be overriden using
the allow_system_table_mods GUC.
This bug exists since 7b504eb282c, adding the extended statistics, so
backpatch all the way back to PostgreSQL 10.
Author: Tomas Vondra
Reported-by: Dean Rasheed
Backpatch-through: 10
Discussion: https://postgr.es/m/CAEZATCXAPrrOKwEsyZKQ4uzzJQWBCt6QAvOcgqRGdWwT1zb%2BrQ%40mail.gmail.com
---
src/backend/commands/statscmds.c | 8 ++++++++
src/test/regress/expected/stats_ext.out | 12 +++++++-----
src/test/regress/sql/stats_ext.sql | 12 +++++++-----
3 files changed, 22 insertions(+), 10 deletions(-)
diff --git a/src/backend/commands/statscmds.c b/src/backend/commands/statscmds.c
index 3bb0d24cd20..1903e093181 100644
--- a/src/backend/commands/statscmds.c
+++ b/src/backend/commands/statscmds.c
@@ -15,6 +15,7 @@
#include "postgres.h"
#include "access/relscan.h"
+#include "catalog/catalog.h"
#include "catalog/dependency.h"
#include "catalog/indexing.h"
#include "catalog/namespace.h"
@@ -124,6 +125,13 @@ CreateStatistics(CreateStatsStmt *stmt)
if (!pg_class_ownercheck(RelationGetRelid(rel), stxowner))
aclcheck_error(ACLCHECK_NOT_OWNER, get_relkind_objtype(rel->rd_rel->relkind),
RelationGetRelationName(rel));
+
+ /* Creating statistics on system catalogs is not allowed */
+ if (!allowSystemTableMods && IsSystemRelation(rel))
+ ereport(ERROR,
+ (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+ errmsg("permission denied: \"%s\" is a system catalog",
+ RelationGetRelationName(rel))));
}
Assert(rel);
diff --git a/src/test/regress/expected/stats_ext.out b/src/test/regress/expected/stats_ext.out
index 5b7e1d46608..914e3f14730 100644
--- a/src/test/regress/expected/stats_ext.out
+++ b/src/test/regress/expected/stats_ext.out
@@ -6,6 +6,7 @@ SET max_parallel_workers = 0;
SET max_parallel_workers_per_gather = 0;
SET work_mem = '128kB';
-- Verify failures
+CREATE TABLE ext_stats_test (x int, y int, z int);
CREATE STATISTICS tst;
ERROR: syntax error at or near ";"
LINE 1: CREATE STATISTICS tst;
@@ -20,16 +21,17 @@ LINE 1: CREATE STATISTICS tst FROM sometab;
^
CREATE STATISTICS tst ON a, b FROM nonexistant;
ERROR: relation "nonexistant" does not exist
-CREATE STATISTICS tst ON a, b FROM pg_class;
+CREATE STATISTICS tst ON a, b FROM ext_stats_test;
ERROR: column "a" does not exist
-CREATE STATISTICS tst ON relname, relname, relnatts FROM pg_class;
+CREATE STATISTICS tst ON x, x, y FROM ext_stats_test;
ERROR: duplicate column name in statistics definition
-CREATE STATISTICS tst ON relnatts + relpages FROM pg_class;
+CREATE STATISTICS tst ON x + y FROM ext_stats_test;
ERROR: only simple column references are allowed in CREATE STATISTICS
-CREATE STATISTICS tst ON (relpages, reltuples) FROM pg_class;
+CREATE STATISTICS tst ON (x, y) FROM ext_stats_test;
ERROR: only simple column references are allowed in CREATE STATISTICS
-CREATE STATISTICS tst (unrecognized) ON relname, relnatts FROM pg_class;
+CREATE STATISTICS tst (unrecognized) ON x, y FROM ext_stats_test;
ERROR: unrecognized statistics kind "unrecognized"
+DROP TABLE ext_stats_test;
-- Ensure stats are dropped sanely, and test IF NOT EXISTS while at it
CREATE TABLE ab1 (a INTEGER, b INTEGER, c INTEGER);
CREATE STATISTICS IF NOT EXISTS ab1_a_b_stats ON a, b FROM ab1;
diff --git a/src/test/regress/sql/stats_ext.sql b/src/test/regress/sql/stats_ext.sql
index 2543dbfffa7..c1dda8ca7de 100644
--- a/src/test/regress/sql/stats_ext.sql
+++ b/src/test/regress/sql/stats_ext.sql
@@ -8,15 +8,17 @@ SET max_parallel_workers_per_gather = 0;
SET work_mem = '128kB';
-- Verify failures
+CREATE TABLE ext_stats_test (x int, y int, z int);
CREATE STATISTICS tst;
CREATE STATISTICS tst ON a, b;
CREATE STATISTICS tst FROM sometab;
CREATE STATISTICS tst ON a, b FROM nonexistant;
-CREATE STATISTICS tst ON a, b FROM pg_class;
-CREATE STATISTICS tst ON relname, relname, relnatts FROM pg_class;
-CREATE STATISTICS tst ON relnatts + relpages FROM pg_class;
-CREATE STATISTICS tst ON (relpages, reltuples) FROM pg_class;
-CREATE STATISTICS tst (unrecognized) ON relname, relnatts FROM pg_class;
+CREATE STATISTICS tst ON a, b FROM ext_stats_test;
+CREATE STATISTICS tst ON x, x, y FROM ext_stats_test;
+CREATE STATISTICS tst ON x + y FROM ext_stats_test;
+CREATE STATISTICS tst ON (x, y) FROM ext_stats_test;
+CREATE STATISTICS tst (unrecognized) ON x, y FROM ext_stats_test;
+DROP TABLE ext_stats_test;
-- Ensure stats are dropped sanely, and test IF NOT EXISTS while at it
CREATE TABLE ab1 (a INTEGER, b INTEGER, c INTEGER);