xds: reject RDS response containing match with case-sensitive false (#3592)

xds/internal/client/v2client_rds.go

@@ -95,9 +95,18 @@ func getClusterFromRouteConfiguration(rc *xdspb.RouteConfiguration, host string)
 		return "", fmt.Errorf("matched virtual host has no routes")
 	}
 	dr := vh.Routes[len(vh.Routes)-1]
-	if match := dr.GetMatch(); match == nil || (match.GetPrefix() != "" && match.GetPrefix() != "/") {
+	match := dr.GetMatch()
+	if match == nil {
+		return "", fmt.Errorf("matched virtual host's default route doesn't have a match")
+	}
+	if prefix := match.GetPrefix(); prefix != "" && prefix != "/" {
 		// The matched virtual host is invalid. Match is not "" or "/".
-		return "", fmt.Errorf("matched virtual host is invalid")
+		return "", fmt.Errorf("matched virtual host's default route is %v, want Prefix empty string or /", match)
+	}
+	if caseSensitive := match.GetCaseSensitive(); caseSensitive != nil && !caseSensitive.Value {
+		// The case sensitive is set to false. Not set or set to true are both
+		// valid.
+		return "", fmt.Errorf("matches virtual host's default route set case-sensitive to false")
 	}
 	if route := dr.GetRoute(); route != nil {
 		return route.GetCluster(), nil

xds/internal/client/v2client_rds_test.go

@@ -25,6 +25,7 @@ import (
 	xdspb "github.com/envoyproxy/go-control-plane/envoy/api/v2"
 	routepb "github.com/envoyproxy/go-control-plane/envoy/api/v2/route"
 	"github.com/golang/protobuf/proto"
+	wrapperspb "github.com/golang/protobuf/ptypes/wrappers"
 	"github.com/google/go-cmp/cmp"
 	"google.golang.org/grpc/xds/internal/testutils/fakeserver"
 )
@@ -141,6 +142,25 @@ func (s) TestRDSGetClusterFromRouteConfiguration(t *testing.T) {
 			wantCluster: "",
 			wantError:   true,
 		},
+		{
+			// default route's match sets case-sensitive to false.
+			name: "good-route-config-but-with-casesensitive-false",
+			rc: &xdspb.RouteConfiguration{
+				Name: goodRouteName1,
+				VirtualHosts: []*routepb.VirtualHost{{
+					Domains: []string{goodLDSTarget1},
+					Routes: []*routepb.Route{{
+						Match: &routepb.RouteMatch{
+							PathSpecifier: &routepb.RouteMatch_Prefix{Prefix: "/"},
+							CaseSensitive: &wrapperspb.BoolValue{Value: false},
+						},
+						Action: &routepb.Route_Route{
+							Route: &routepb.RouteAction{
+								ClusterSpecifier: &routepb.RouteAction_Cluster{Cluster: goodClusterName1},
+							}}}}}}},
+			wantCluster: "",
+			wantError:   true,
+		},
 		{
 			name:        "good-route-config-with-empty-string-route",
 			rc:          goodRouteConfig1,