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-rw-r--r--src/backend/statistics/extended_stats.c74
-rw-r--r--src/test/regress/expected/stats_ext.out60
-rw-r--r--src/test/regress/sql/stats_ext.sql60
3 files changed, 186 insertions, 8 deletions
diff --git a/src/backend/statistics/extended_stats.c b/src/backend/statistics/extended_stats.c
index 96db32f0a0a..c56ed482706 100644
--- a/src/backend/statistics/extended_stats.c
+++ b/src/backend/statistics/extended_stats.c
@@ -24,6 +24,7 @@
#include "catalog/pg_collation.h"
#include "catalog/pg_statistic_ext.h"
#include "catalog/pg_statistic_ext_data.h"
+#include "miscadmin.h"
#include "nodes/nodeFuncs.h"
#include "optimizer/clauses.h"
#include "optimizer/optimizer.h"
@@ -760,7 +761,8 @@ choose_best_statistics(List *stats, Bitmapset *attnums, char requiredkind)
* attribute numbers from all compatible clauses (recursively).
*/
static bool
-statext_is_compatible_clause_internal(Node *clause, Index relid, Bitmapset **attnums)
+statext_is_compatible_clause_internal(PlannerInfo *root, Node *clause,
+ Index relid, Bitmapset **attnums)
{
/* Look inside any binary-compatible relabeling (as in examine_variable) */
if (IsA(clause, RelabelType))
@@ -791,6 +793,7 @@ statext_is_compatible_clause_internal(Node *clause, Index relid, Bitmapset **att
/* (Var op Const) or (Const op Var) */
if (is_opclause(clause))
{
+ RangeTblEntry *rte = root->simple_rte_array[relid];
OpExpr *expr = (OpExpr *) clause;
Var *var;
bool varonleft = true;
@@ -833,9 +836,24 @@ statext_is_compatible_clause_internal(Node *clause, Index relid, Bitmapset **att
return false;
}
+ /*
+ * If there are any securityQuals on the RTE from security barrier
+ * views or RLS policies, then the user may not have access to all the
+ * table's data, and we must check that the operator is leak-proof.
+ *
+ * If the operator is leaky, then we must ignore this clause for the
+ * purposes of estimating with MCV lists, otherwise the operator might
+ * reveal values from the MCV list that the user doesn't have
+ * permission to see.
+ */
+ if (rte->securityQuals != NIL &&
+ !get_func_leakproof(get_opcode(expr->opno)))
+ return false;
+
var = (varonleft) ? linitial(expr->args) : lsecond(expr->args);
- return statext_is_compatible_clause_internal((Node *) var, relid, attnums);
+ return statext_is_compatible_clause_internal(root, (Node *) var,
+ relid, attnums);
}
/* AND/OR/NOT clause */
@@ -866,7 +884,8 @@ statext_is_compatible_clause_internal(Node *clause, Index relid, Bitmapset **att
* Had we found incompatible clause in the arguments, treat the
* whole clause as incompatible.
*/
- if (!statext_is_compatible_clause_internal((Node *) lfirst(lc),
+ if (!statext_is_compatible_clause_internal(root,
+ (Node *) lfirst(lc),
relid, attnums))
return false;
}
@@ -886,7 +905,8 @@ statext_is_compatible_clause_internal(Node *clause, Index relid, Bitmapset **att
if (!IsA(nt->arg, Var))
return false;
- return statext_is_compatible_clause_internal((Node *) (nt->arg), relid, attnums);
+ return statext_is_compatible_clause_internal(root, (Node *) (nt->arg),
+ relid, attnums);
}
return false;
@@ -909,9 +929,12 @@ statext_is_compatible_clause_internal(Node *clause, Index relid, Bitmapset **att
* complex cases, for example (Var op Var).
*/
static bool
-statext_is_compatible_clause(Node *clause, Index relid, Bitmapset **attnums)
+statext_is_compatible_clause(PlannerInfo *root, Node *clause, Index relid,
+ Bitmapset **attnums)
{
+ RangeTblEntry *rte = root->simple_rte_array[relid];
RestrictInfo *rinfo = (RestrictInfo *) clause;
+ Oid userid;
if (!IsA(rinfo, RestrictInfo))
return false;
@@ -924,8 +947,43 @@ statext_is_compatible_clause(Node *clause, Index relid, Bitmapset **attnums)
if (bms_membership(rinfo->clause_relids) != BMS_SINGLETON)
return false;
- return statext_is_compatible_clause_internal((Node *) rinfo->clause,
- relid, attnums);
+ /* Check the clause and determine what attributes it references. */
+ if (!statext_is_compatible_clause_internal(root, (Node *) rinfo->clause,
+ relid, attnums))
+ return false;
+
+ /*
+ * Check that the user has permission to read all these attributes. Use
+ * checkAsUser if it's set, in case we're accessing the table via a view.
+ */
+ userid = rte->checkAsUser ? rte->checkAsUser : GetUserId();
+
+ if (pg_class_aclcheck(rte->relid, userid, ACL_SELECT) != ACLCHECK_OK)
+ {
+ /* Don't have table privilege, must check individual columns */
+ if (bms_is_member(InvalidAttrNumber, *attnums))
+ {
+ /* Have a whole-row reference, must have access to all columns */
+ if (pg_attribute_aclcheck_all(rte->relid, userid, ACL_SELECT,
+ ACLMASK_ALL) != ACLCHECK_OK)
+ return false;
+ }
+ else
+ {
+ /* Check the columns referenced by the clause */
+ int attnum = -1;
+
+ while ((attnum = bms_next_member(*attnums, attnum)) >= 0)
+ {
+ if (pg_attribute_aclcheck(rte->relid, attnum, userid,
+ ACL_SELECT) != ACLCHECK_OK)
+ return false;
+ }
+ }
+ }
+
+ /* If we reach here, the clause is OK */
+ return true;
}
/*
@@ -1027,7 +1085,7 @@ statext_mcv_clauselist_selectivity(PlannerInfo *root, List *clauses, int varReli
Bitmapset *attnums = NULL;
if (!bms_is_member(listidx, *estimatedclauses) &&
- statext_is_compatible_clause(clause, rel->relid, &attnums))
+ statext_is_compatible_clause(root, clause, rel->relid, &attnums))
{
list_attnums[listidx] = attnums;
clauses_attnums = bms_add_members(clauses_attnums, attnums);
diff --git a/src/test/regress/expected/stats_ext.out b/src/test/regress/expected/stats_ext.out
index def95d80c9b..c893f01c55c 100644
--- a/src/test/regress/expected/stats_ext.out
+++ b/src/test/regress/expected/stats_ext.out
@@ -696,3 +696,63 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a AND
1 | 0
(1 row)
+-- Permission tests. Users should not be able to see specific data values in
+-- the extended statistics, if they lack permission to see those values in
+-- the underlying table.
+--
+-- Currently this is only relevant for MCV stats.
+CREATE TABLE priv_test_tbl (
+ a int,
+ b int
+);
+INSERT INTO priv_test_tbl
+ SELECT mod(i,5), mod(i,10) FROM generate_series(1,100) s(i);
+CREATE STATISTICS priv_test_stats (mcv) ON a, b
+ FROM priv_test_tbl;
+ANALYZE priv_test_tbl;
+-- User with no access
+CREATE USER regress_stats_user1;
+SET SESSION AUTHORIZATION regress_stats_user1;
+SELECT * FROM priv_test_tbl; -- Permission denied
+ERROR: permission denied for table priv_test_tbl
+-- Attempt to gain access using a leaky operator
+CREATE FUNCTION op_leak(int, int) RETURNS bool
+ AS 'BEGIN RAISE NOTICE ''op_leak => %, %'', $1, $2; RETURN $1 < $2; END'
+ LANGUAGE plpgsql;
+CREATE OPERATOR <<< (procedure = op_leak, leftarg = int, rightarg = int,
+ restrict = scalarltsel);
+SELECT * FROM priv_test_tbl WHERE a <<< 0 AND b <<< 0; -- Permission denied
+ERROR: permission denied for table priv_test_tbl
+DELETE FROM priv_test_tbl WHERE a <<< 0 AND b <<< 0; -- Permission denied
+ERROR: permission denied for table priv_test_tbl
+-- Grant access via a security barrier view, but hide all data
+RESET SESSION AUTHORIZATION;
+CREATE VIEW priv_test_view WITH (security_barrier=true)
+ AS SELECT * FROM priv_test_tbl WHERE false;
+GRANT SELECT, DELETE ON priv_test_view TO regress_stats_user1;
+-- Should now have access via the view, but see nothing and leak nothing
+SET SESSION AUTHORIZATION regress_stats_user1;
+SELECT * FROM priv_test_view WHERE a <<< 0 AND b <<< 0; -- Should not leak
+ a | b
+---+---
+(0 rows)
+
+DELETE FROM priv_test_view WHERE a <<< 0 AND b <<< 0; -- Should not leak
+-- Grant table access, but hide all data with RLS
+RESET SESSION AUTHORIZATION;
+ALTER TABLE priv_test_tbl ENABLE ROW LEVEL SECURITY;
+GRANT SELECT, DELETE ON priv_test_tbl TO regress_stats_user1;
+-- Should now have direct table access, but see nothing and leak nothing
+SET SESSION AUTHORIZATION regress_stats_user1;
+SELECT * FROM priv_test_tbl WHERE a <<< 0 AND b <<< 0; -- Should not leak
+ a | b
+---+---
+(0 rows)
+
+DELETE FROM priv_test_tbl WHERE a <<< 0 AND b <<< 0; -- Should not leak
+-- Tidy up
+DROP OPERATOR <<< (int, int);
+DROP FUNCTION op_leak(int, int);
+RESET SESSION AUTHORIZATION;
+DROP VIEW priv_test_view;
+DROP TABLE priv_test_tbl;
diff --git a/src/test/regress/sql/stats_ext.sql b/src/test/regress/sql/stats_ext.sql
index 3aa99d7bc81..5138ce09548 100644
--- a/src/test/regress/sql/stats_ext.sql
+++ b/src/test/regress/sql/stats_ext.sql
@@ -446,3 +446,63 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a AND
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a AND NOT b AND c');
SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a AND b AND NOT c');
+
+-- Permission tests. Users should not be able to see specific data values in
+-- the extended statistics, if they lack permission to see those values in
+-- the underlying table.
+--
+-- Currently this is only relevant for MCV stats.
+CREATE TABLE priv_test_tbl (
+ a int,
+ b int
+);
+
+INSERT INTO priv_test_tbl
+ SELECT mod(i,5), mod(i,10) FROM generate_series(1,100) s(i);
+
+CREATE STATISTICS priv_test_stats (mcv) ON a, b
+ FROM priv_test_tbl;
+
+ANALYZE priv_test_tbl;
+
+-- User with no access
+CREATE USER regress_stats_user1;
+SET SESSION AUTHORIZATION regress_stats_user1;
+SELECT * FROM priv_test_tbl; -- Permission denied
+
+-- Attempt to gain access using a leaky operator
+CREATE FUNCTION op_leak(int, int) RETURNS bool
+ AS 'BEGIN RAISE NOTICE ''op_leak => %, %'', $1, $2; RETURN $1 < $2; END'
+ LANGUAGE plpgsql;
+CREATE OPERATOR <<< (procedure = op_leak, leftarg = int, rightarg = int,
+ restrict = scalarltsel);
+SELECT * FROM priv_test_tbl WHERE a <<< 0 AND b <<< 0; -- Permission denied
+DELETE FROM priv_test_tbl WHERE a <<< 0 AND b <<< 0; -- Permission denied
+
+-- Grant access via a security barrier view, but hide all data
+RESET SESSION AUTHORIZATION;
+CREATE VIEW priv_test_view WITH (security_barrier=true)
+ AS SELECT * FROM priv_test_tbl WHERE false;
+GRANT SELECT, DELETE ON priv_test_view TO regress_stats_user1;
+
+-- Should now have access via the view, but see nothing and leak nothing
+SET SESSION AUTHORIZATION regress_stats_user1;
+SELECT * FROM priv_test_view WHERE a <<< 0 AND b <<< 0; -- Should not leak
+DELETE FROM priv_test_view WHERE a <<< 0 AND b <<< 0; -- Should not leak
+
+-- Grant table access, but hide all data with RLS
+RESET SESSION AUTHORIZATION;
+ALTER TABLE priv_test_tbl ENABLE ROW LEVEL SECURITY;
+GRANT SELECT, DELETE ON priv_test_tbl TO regress_stats_user1;
+
+-- Should now have direct table access, but see nothing and leak nothing
+SET SESSION AUTHORIZATION regress_stats_user1;
+SELECT * FROM priv_test_tbl WHERE a <<< 0 AND b <<< 0; -- Should not leak
+DELETE FROM priv_test_tbl WHERE a <<< 0 AND b <<< 0; -- Should not leak
+
+-- Tidy up
+DROP OPERATOR <<< (int, int);
+DROP FUNCTION op_leak(int, int);
+RESET SESSION AUTHORIZATION;
+DROP VIEW priv_test_view;
+DROP TABLE priv_test_tbl;
generated by cgit v1.2.3 (git 2.25.1) at 2025-06-15 12:34:56 +0000