sql: fix SHOW ALL ZONE CONFIGURATION displaying unprivileged entries

* Made `crdb_internal.zones` not display entries which the executing
user does not have access to.
* Add a delegate for ShowZoneConfig, which triggers on SHOW ALL
ZONE CONFIGURATIONS, to use crdb_internal.zones table and run it as
the executing user so rows are hidden if the user does not have
permission.

Release note (bug fix): Previously, SHOW ALL ZONE CONFIGURATION ZONES
and crdb_internal.zones shows results for resources the user does not
have access to. This will instead filter out those entries from
displaying.

pkg/ccl/logictestccl/testdata/logic_test/crdb_internal

@@ -56,13 +56,59 @@ statement ok
 CREATE DATABASE db2; ALTER DATABASE db2 CONFIGURE ZONE USING num_replicas = 3;
 
 statement ok
-CREATE TABLE t3 (a INT PRIMARY KEY, b INT); CREATE INDEX myindex ON t3 (b); ALTER INDEX myindex CONFIGURE ZONE USING num_replicas = 5; ALTER TABLE t3 CONFIGURE ZONE USING num_replicas = 8
+CREATE TABLE t3 (a INT PRIMARY KEY, b INT); CREATE INDEX myt3index ON t3 (b); ALTER INDEX myt3index CONFIGURE ZONE USING num_replicas = 5; ALTER TABLE t3 CONFIGURE ZONE USING num_replicas = 8
 
 statement ok
-CREATE TABLE t4 (a INT PRIMARY KEY, b INT); ALTER TABLE t4 CONFIGURE ZONE USING num_replicas = 7; GRANT ALL ON t4 TO testuser
+CREATE TABLE t4 (a INT PRIMARY KEY, b INT); CREATE INDEX myt4index ON t4 (b); ALTER TABLE t4 CONFIGURE ZONE USING num_replicas = 7; ALTER INDEX myt4index CONFIGURE ZONE USING num_replicas = 5; GRANT ALL ON t4 TO testuser
 
 user testuser
 
+query IT
+SELECT zone_id, target FROM crdb_internal.zones ORDER BY 1
+----
+0   RANGE default
+16  RANGE meta
+17  RANGE system
+22  RANGE liveness
+57  TABLE test.public.t4
+57  INDEX test.public.t4@myt4index
+
+query TT
+SELECT * FROM [SHOW ALL ZONE CONFIGURATIONS] ORDER BY 1
+----
+INDEX test.public.t4@myt4index  ALTER INDEX test.public.t4@myt4index CONFIGURE ZONE USING
+                                num_replicas = 5
+RANGE default                   ALTER RANGE default CONFIGURE ZONE USING
+                                range_min_bytes = 16777216,
+                                range_max_bytes = 67108864,
+                                gc.ttlseconds = 90000,
+                                num_replicas = 3,
+                                constraints = '[]',
+                                lease_preferences = '[]'
+RANGE liveness                  ALTER RANGE liveness CONFIGURE ZONE USING
+                                range_min_bytes = 16777216,
+                                range_max_bytes = 67108864,
+                                gc.ttlseconds = 600,
+                                num_replicas = 5,
+                                constraints = '[]',
+                                lease_preferences = '[]'
+RANGE meta                      ALTER RANGE meta CONFIGURE ZONE USING
+                                range_min_bytes = 16777216,
+                                range_max_bytes = 67108864,
+                                gc.ttlseconds = 3600,
+                                num_replicas = 5,
+                                constraints = '[]',
+                                lease_preferences = '[]'
+RANGE system                    ALTER RANGE system CONFIGURE ZONE USING
+                                range_min_bytes = 16777216,
+                                range_max_bytes = 67108864,
+                                gc.ttlseconds = 90000,
+                                num_replicas = 5,
+                                constraints = '[]',
+                                lease_preferences = '[]'
+TABLE test.public.t4            ALTER TABLE test.public.t4 CONFIGURE ZONE USING
+                                num_replicas = 7
+
 query error pq: user testuser has no privileges on database db2
 SHOW ZONE CONFIGURATION FOR DATABASE db2
 
@@ -72,6 +118,20 @@ SHOW ZONE CONFIGURATION FOR TABLE t2
 query error pq: user testuser has no privileges on relation t3
 SHOW ZONE CONFIGURATION FOR TABLE t3
 
+query error pq: user testuser has no privileges on relation t3
+SHOW ZONE CONFIGURATION FOR INDEX myt3index
+
+query TT
+SHOW ZONE CONFIGURATION FOR INDEX myt4index
+----
+INDEX test.public.t4@myt4index  ALTER INDEX test.public.t4@myt4index CONFIGURE ZONE USING
+                                range_min_bytes = 16777216,
+                                range_max_bytes = 67108864,
+                                gc.ttlseconds = 90000,
+                                num_replicas = 5,
+                                constraints = '[]',
+                                lease_preferences = '[]'
+
 query TT
 SHOW ZONE CONFIGURATION FOR TABLE t4
 ----

pkg/sql/crdb_internal.go

@@ -2163,6 +2163,25 @@ CREATE TABLE crdb_internal.zones (
 				return err
 			}
 
+			var table *TableDescriptor
+			if zs.Database != "" {
+				database, err := sqlbase.GetDatabaseDescFromID(ctx, p.txn, sqlbase.ID(id))
+				if err != nil {
+					return err
+				}
+				if p.CheckAnyPrivilege(ctx, database) != nil {
+					continue
+				}
+			} else if zoneSpecifier.TableOrIndex.Table.TableName != "" {
+				table, err = sqlbase.GetTableDescFromID(ctx, p.txn, sqlbase.ID(id))
+				if err != nil {
+					return err
+				}
+				if p.CheckAnyPrivilege(ctx, table) != nil {
+					continue
+				}
+			}
+
 			// Write down information about the zone in the table.
 			// TODO (rohany): We would like to just display information about these
 			//  subzone placeholders, but there are a few tests that depend on this
@@ -2189,10 +2208,14 @@ CREATE TABLE crdb_internal.zones (
 			}
 
 			if len(subzones) > 0 {
-				table, err := sqlbase.GetTableDescFromID(ctx, p.txn, sqlbase.ID(id))
-				if err != nil {
-					return err
+				if table == nil {
+					return errors.AssertionFailedf(
+						"object id %d with #subzones %d is not a table",
+						id,
+						len(subzones),
+					)
 				}
+
 				for i, s := range subzones {
 					index, err := table.FindIndexByID(sqlbase.IndexID(s.IndexID))
 					if err != nil {

pkg/sql/delegate/delegate.go

@@ -102,6 +102,9 @@ func TryDelegate(
 	case *tree.ShowVar:
 		return d.delegateShowVar(t)
 
+	case *tree.ShowZoneConfig:
+		return d.delegateShowZoneConfig(t)
+
 	case *tree.ShowTransactionStatus:
 		return d.delegateShowVar(&tree.ShowVar{Name: "transaction_status"})
 

pkg/sql/delegate/show_zone_config.go

@@ -0,0 +1,22 @@
+// Copyright 2019 The Cockroach Authors.
+//
+// Use of this software is governed by the Business Source License
+// included in the file licenses/BSL.txt.
+//
+// As of the Change Date specified in that file, in accordance with
+// the Business Source License, use of this software will be governed
+// by the Apache License, Version 2.0, included in the file
+// licenses/APL.txt.
+
+package delegate
+
+import "github.com/cockroachdb/cockroach/pkg/sql/sem/tree"
+
+// ShowZoneConfig only delegates if it selecting ALL configurations.
+func (d *delegator) delegateShowZoneConfig(n *tree.ShowZoneConfig) (tree.Statement, error) {
+	// Specifying a specific zone; fallback to non-delegation logic.
+	if n.ZoneSpecifier != (tree.ZoneSpecifier{}) {
+		return nil, nil
+	}
+	return parse(`SELECT target, raw_config_sql FROM crdb_internal.zones`)
+}

pkg/sql/show_zone_config.go

@@ -22,6 +22,7 @@ import (
 	"github.com/cockroachdb/cockroach/pkg/sql/sqlbase"
 	"github.com/cockroachdb/cockroach/pkg/sql/types"
 	"github.com/cockroachdb/cockroach/pkg/util/protoutil"
+	"github.com/cockroachdb/errors"
 	"gopkg.in/yaml.v2"
 )
 
@@ -66,33 +67,20 @@ func (p *planner) ShowZoneConfig(ctx context.Context, n *tree.ShowZoneConfig) (p
 		constructor: func(ctx context.Context, p *planner) (planNode, error) {
 			v := p.newContainerValuesNode(showZoneConfigColumns, 0)
 
+			// This signifies SHOW ALL.
+			// However, SHOW ALL should be handled by the delegate.
 			if n.ZoneSpecifier == (tree.ZoneSpecifier{}) {
-				// SHOW ALL ZONE CONFIGURATIONS case.
-				rows, err := p.ExtendedEvalContext().ExecCfg.InternalExecutor.Query(
-					ctx,
-					"show-all-zone-configurations",
-					p.txn,
-					`SELECT * FROM crdb_internal.zones`,
-				)
-				if err != nil {
-					return nil, err
-				}
-				for i := range rows {
-					if _, err := v.rows.AddRow(ctx, rows[i]); err != nil {
-						v.Close(ctx)
-						return nil, err
-					}
-				}
-			} else {
-				row, err := getShowZoneConfigRow(ctx, p, n.ZoneSpecifier)
-				if err != nil {
-					v.Close(ctx)
-					return nil, err
-				}
-				if _, err := v.rows.AddRow(ctx, row); err != nil {
-					v.Close(ctx)
-					return nil, err
-				}
+				return nil, errors.AssertionFailedf("zone must be specified")
+			}
+
+			row, err := getShowZoneConfigRow(ctx, p, n.ZoneSpecifier)
+			if err != nil {
+				v.Close(ctx)
+				return nil, err
+			}
+			if _, err := v.rows.AddRow(ctx, row); err != nil {
+				v.Close(ctx)
+				return nil, err
 			}
 			return v, nil
 		},