server: allow users with VIEWACTIVITY to get console settings

Previously, only users with `ADMIN`, `VIEWCLUSTERSETTING` or
`MODIFYCLUSTERSETTING` could get the settings on the
`_admin/v1/settings`. This API was used by the Console and then
a few places retrieved that information.
Users without those permissions would not be able to see the
values and some functionalities where not working as expected,
for example timezone was showing as UTC even when the cluster
setting `ui.display_timezone` was set to other value.

This commits modifies that endpoint (and that endpoint only)
to return just the cluster settings that are not sensitive and
that are required by the console to have all functionalities
working.

The list of cluster settings:
"cross_cluster_replication.enabled",
"keyvisualizer.enabled",
"keyvisualizer.sample_interval",
"sql.index_recommendation.drop_unused_duration",
"sql.insights.anomaly_detection.latency_threshold",
"sql.insights.high_retry_count.threshold",
"sql.insights.latency_threshold",
"sql.stats.automatic_collection.enabled",
"timeseries.storage.resolution_10s.ttl",
"timeseries.storage.resolution_30m.ttl",
"ui.display_timezone",
"version"

Part Of cockroachdb#108373

Release note (bug fix): Users with VIEWACTIVITY can now view
correct values for timezone.

pkg/server/BUILD.bazel

@@ -347,6 +347,7 @@ go_library(
         "@org_golang_google_grpc//codes",
         "@org_golang_google_grpc//metadata",
         "@org_golang_google_grpc//status",
+        "@org_golang_x_exp//slices",
     ] + select({
         "@io_bazel_rules_go//go/platform:aix": [
             "@org_golang_x_sys//unix",

pkg/server/admin.go

@@ -81,6 +81,7 @@ import (
 	"github.com/cockroachdb/errors"
 	gwruntime "github.com/grpc-ecosystem/grpc-gateway/runtime"
 	gwutil "github.com/grpc-ecosystem/grpc-gateway/utilities"
+	"golang.org/x/exp/slices"
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/codes"
 	grpcstatus "google.golang.org/grpc/status"
@@ -2020,17 +2021,15 @@ func (s *adminServer) Settings(
 ) (*serverpb.SettingsResponse, error) {
 	ctx = s.AnnotateCtx(ctx)
 
-	keys := req.Keys
-	if len(keys) == 0 {
-		keys = settings.Keys(settings.ForSystemTenant)
-	}
-
 	_, isAdmin, err := s.getUserAndRole(ctx)
 	if err != nil {
 		return nil, serverError(ctx, err)
 	}
 
 	redactValues := true
+	// Only returns non-sensitive settings that are required
+	// for features on DB Console.
+	consoleSettingsOnly := false
 	if isAdmin {
 		// Root accesses can customize the purpose.
 		// This is used by the UI to see all values (local access)
@@ -2039,9 +2038,37 @@ func (s *adminServer) Settings(
 			redactValues = false
 		}
 	} else {
-		// Non-root access cannot see the values in any case.
+		// Non-root access cannot see the values.
+		// Exception: users with VIEWACTIVITY and VIEWACTIVITYREDACTED can see cluster
+		// settings used by the UI Console.
 		if err := s.adminPrivilegeChecker.requireViewClusterSettingOrModifyClusterSettingPermission(ctx); err != nil {
-			return nil, err
+			if err2 := s.adminPrivilegeChecker.requireViewActivityOrViewActivityRedactedPermission(ctx); err2 != nil {
+				// The check for VIEWACTIVITY or VIEWATIVITYREDACTED is a special case so cluster settings from
+				// the console can be returned, but if the user doesn't have them (i.e. err2 != nil), we don't want
+				// to share this error message, so only return `err`.
+				return nil, err
+			}
+			consoleSettingsOnly = true
+		}
+	}
+
+	var settingsKeys []string
+	if !consoleSettingsOnly {
+		settingsKeys = req.Keys
+		if len(settingsKeys) == 0 {
+			settingsKeys = settings.Keys(settings.ForSystemTenant)
+		}
+	} else {
+
+		if len(req.Keys) == 0 {
+			settingsKeys = settings.ConsoleKeys()
+		} else {
+			settingsKeys = []string{}
+			for _, k := range req.Keys {
+				if slices.Contains(settings.ConsoleKeys(), k) {
+					settingsKeys = append(settingsKeys, k)
+				}
+			}
 		}
 	}
 
@@ -2071,7 +2098,7 @@ func (s *adminServer) Settings(
 	}
 
 	resp := serverpb.SettingsResponse{KeyValues: make(map[string]serverpb.SettingsResponse_Value)}
-	for _, k := range keys {
+	for _, k := range settingsKeys {
 		var v settings.Setting
 		var ok bool
 		if redactValues {

pkg/settings/registry.go

@@ -282,6 +282,29 @@ func Keys(forSystemTenant bool) (res []string) {
 	return res
 }
 
+// ConsoleKeys return an array with all cluster settings keys
+// used by the UI Console.
+// This list should only contain settings that have no sensitive
+// information, because it will be returned on `settings` endpoint for
+// users without VIEWCLUSTERSETTING or MODIFYCLUSTERSETTING permission,
+// but that have VIEWACTIVITY or VIEWACTIVITYREDACTED permissions.
+func ConsoleKeys() (res []string) {
+	return []string{
+		"cross_cluster_replication.enabled",
+		"keyvisualizer.enabled",
+		"keyvisualizer.sample_interval",
+		"sql.index_recommendation.drop_unused_duration",
+		"sql.insights.anomaly_detection.latency_threshold",
+		"sql.insights.high_retry_count.threshold",
+		"sql.insights.latency_threshold",
+		"sql.stats.automatic_collection.enabled",
+		"timeseries.storage.resolution_10s.ttl",
+		"timeseries.storage.resolution_30m.ttl",
+		"ui.display_timezone",
+		"version",
+	}
+}
+
 // LookupForLocalAccess returns a NonMaskedSetting by name. Used when a setting
 // is being retrieved for local processing within the cluster and not for
 // reporting; sensitive values are accessible.