snapshot of https://github.com/grpc/grpc-go.git (master, 2026-09-15; blobs > 131072B omitted)

authz/grpc_authz_end2end_test.go

@@ -0,0 +1,708 @@
+/*
+ *
+ * Copyright 2021 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package authz_test
+
+import (
+	"context"
+	"crypto/tls"
+	"crypto/x509"
+	"io"
+	"os"
+	"testing"
+	"time"
+
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/authz"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/credentials"
+	"google.golang.org/grpc/credentials/insecure"
+	"google.golang.org/grpc/internal/grpctest"
+	"google.golang.org/grpc/internal/stubserver"
+	"google.golang.org/grpc/metadata"
+	"google.golang.org/grpc/status"
+	"google.golang.org/grpc/testdata"
+
+	testgrpc "google.golang.org/grpc/interop/grpc_testing"
+	testpb "google.golang.org/grpc/interop/grpc_testing"
+)
+
+type s struct {
+	grpctest.Tester
+}
+
+func Test(t *testing.T) {
+	grpctest.RunSubTests(t, s{})
+}
+
+var authzTests = map[string]struct {
+	authzPolicy string
+	md          metadata.MD
+	wantStatus  *status.Status
+}{
+	"DeniesRPCMatchInDenyNoMatchInAllow": {
+		authzPolicy: `{
+				"name": "authz",
+				"allow_rules":
+				[
+					{
+						"name": "allow_StreamingOutputCall",
+						"request": {
+							"paths":
+							[
+								"/grpc.testing.TestService/StreamingOutputCall"
+							]
+						}
+					}
+				],
+				"deny_rules":
+				[
+					{
+						"name": "deny_TestServiceCalls",
+						"request": {
+							"paths":
+							[
+								"/grpc.testing.TestService/*"
+							],
+							"headers":
+							[
+								{
+									"key": "key-abc",
+									"values":
+									[
+										"val-abc",
+										"val-def"
+									]
+								}
+							]
+						}
+					}
+				]
+			}`,
+		md:         metadata.Pairs("key-abc", "val-abc"),
+		wantStatus: status.New(codes.PermissionDenied, "authz: unauthorized RPC request rejected"),
+	},
+	"DeniesRPCMatchInDenyAndAllow": {
+		authzPolicy: `{
+				"name": "authz",
+				"allow_rules":
+				[
+					{
+						"name": "allow_all",
+						"request": {
+							"paths":
+							[
+								"*"
+							]
+						}
+					}
+				],
+				"deny_rules":
+				[
+					{
+						"name": "deny_all",
+						"request": {
+							"paths":
+							[
+								"*"
+							]
+						}
+					}
+				]
+			}`,
+		wantStatus: status.New(codes.PermissionDenied, "authz: unauthorized RPC request rejected"),
+	},
+	"AllowsRPCNoMatchInDenyMatchInAllow": {
+		authzPolicy: `{
+				"name": "authz",
+				"allow_rules":
+				[
+					{
+						"name": "allow_all"
+					}
+				],
+				"deny_rules":
+				[
+					{
+						"name": "deny_TestServiceCalls",
+						"request": {
+							"paths":
+							[
+								"/grpc.testing.TestService/UnaryCall",
+								"/grpc.testing.TestService/StreamingInputCall"
+							],
+							"headers":
+							[
+								{
+									"key": "key-abc",
+									"values":
+									[
+										"val-abc",
+										"val-def"
+									]
+								}
+							]
+						}
+					}
+				]
+			}`,
+		md:         metadata.Pairs("key-xyz", "val-xyz"),
+		wantStatus: status.New(codes.OK, ""),
+	},
+	"DeniesRPCNoMatchInDenyAndAllow": {
+		authzPolicy: `{
+				"name": "authz",
+				"allow_rules":
+				[
+					{
+						"name": "allow_some_user",
+						"source": {
+							"principals":
+							[
+								"some_user"
+							]
+						}
+					}
+				],
+				"deny_rules":
+				[
+					{
+						"name": "deny_StreamingOutputCall",
+						"request": {
+							"paths":
+							[
+								"/grpc.testing.TestService/StreamingOutputCall"
+							]
+						}
+					}
+				]
+			}`,
+		wantStatus: status.New(codes.PermissionDenied, "authz: unauthorized RPC request rejected"),
+	},
+	"AllowsRPCEmptyDenyMatchInAllow": {
+		authzPolicy: `{
+				"name": "authz",
+				"allow_rules":
+				[
+					{
+						"name": "allow_UnaryCall",
+						"request":
+						{
+							"paths":
+							[
+								"/grpc.testing.TestService/UnaryCall"
+							]
+						}
+					},
+					{
+						"name": "allow_StreamingInputCall",
+						"request":
+						{
+							"paths":
+							[
+								"/grpc.testing.TestService/StreamingInputCall"
+							]
+						}
+					}
+				]
+			}`,
+		wantStatus: status.New(codes.OK, ""),
+	},
+	"DeniesRPCEmptyDenyNoMatchInAllow": {
+		authzPolicy: `{
+				"name": "authz",
+				"allow_rules":
+				[
+					{
+						"name": "allow_StreamingOutputCall",
+						"request":
+						{
+							"paths":
+							[
+								"/grpc.testing.TestService/StreamingOutputCall"
+							]
+						}
+					}
+				]
+			}`,
+		wantStatus: status.New(codes.PermissionDenied, "authz: unauthorized RPC request rejected"),
+	},
+	"DeniesRPCRequestWithPrincipalsFieldOnUnauthenticatedConnection": {
+		authzPolicy: `{
+				"name": "authz",
+				"allow_rules":
+				[
+					{
+						"name": "allow_authenticated",
+						"source": {
+							"principals": ["*", ""]
+						}
+					}
+				]
+			}`,
+		wantStatus: status.New(codes.PermissionDenied, "authz: unauthorized RPC request rejected"),
+	},
+	"DeniesRPCRequestNoMatchInAllowFailsPresenceMatch": {
+		authzPolicy: `{
+				"name": "authz",
+				"allow_rules":
+				[
+					{
+						"name": "allow_TestServiceCalls",
+						"request": {
+							"paths":
+							[
+								"/grpc.testing.TestService/*"
+							],
+							"headers":
+							[
+								{
+									"key": "key-abc",
+									"values":
+									[
+										"*"
+									]
+								}
+							]
+						}
+					}
+				]
+			}`,
+		md:         metadata.Pairs("key-abc", ""),
+		wantStatus: status.New(codes.PermissionDenied, "authz: unauthorized RPC request rejected"),
+	},
+}
+
+func (s) TestStaticPolicyEnd2End(t *testing.T) {
+	for name, test := range authzTests {
+		t.Run(name, func(t *testing.T) {
+			// Start a gRPC server with gRPC authz unary and stream server interceptors.
+			i, _ := authz.NewStatic(test.authzPolicy)
+
+			stub := &stubserver.StubServer{
+				UnaryCallF: func(context.Context, *testpb.SimpleRequest) (*testpb.SimpleResponse, error) {
+					return &testpb.SimpleResponse{}, nil
+				},
+				StreamingInputCallF: func(stream testgrpc.TestService_StreamingInputCallServer) error {
+					for {
+						_, err := stream.Recv()
+						if err == io.EOF {
+							return stream.SendAndClose(&testpb.StreamingInputCallResponse{})
+						}
+						if err != nil {
+							return err
+						}
+					}
+				},
+				S: grpc.NewServer(grpc.ChainUnaryInterceptor(i.UnaryInterceptor), grpc.ChainStreamInterceptor(i.StreamInterceptor)),
+			}
+			stubserver.StartTestService(t, stub)
+			defer stub.Stop()
+
+			// Establish a connection to the server.
+			cc, err := grpc.NewClient(stub.Address, grpc.WithTransportCredentials(insecure.NewCredentials()))
+			if err != nil {
+				t.Fatalf("grpc.NewClient(%v) failed: %v", stub.Address, err)
+			}
+			defer cc.Close()
+			client := testgrpc.NewTestServiceClient(cc)
+
+			ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+			defer cancel()
+			ctx = metadata.NewOutgoingContext(ctx, test.md)
+
+			// Verifying authorization decision for Unary RPC.
+			_, err = client.UnaryCall(ctx, &testpb.SimpleRequest{})
+			if got := status.Convert(err); got.Code() != test.wantStatus.Code() || got.Message() != test.wantStatus.Message() {
+				t.Fatalf("[UnaryCall] error want:{%v} got:{%v}", test.wantStatus.Err(), got.Err())
+			}
+
+			// Verifying authorization decision for Streaming RPC.
+			stream, err := client.StreamingInputCall(ctx)
+			if err != nil {
+				t.Fatalf("failed StreamingInputCall err: %v", err)
+			}
+			req := &testpb.StreamingInputCallRequest{
+				Payload: &testpb.Payload{
+					Body: []byte("hi"),
+				},
+			}
+			if err := stream.Send(req); err != nil && err != io.EOF {
+				t.Fatalf("failed stream.Send err: %v", err)
+			}
+			_, err = stream.CloseAndRecv()
+			if got := status.Convert(err); got.Code() != test.wantStatus.Code() || got.Message() != test.wantStatus.Message() {
+				t.Fatalf("[StreamingCall] error want:{%v} got:{%v}", test.wantStatus.Err(), got.Err())
+			}
+		})
+	}
+}
+
+func (s) TestAllowsRPCRequestWithPrincipalsFieldOnTLSAuthenticatedConnection(t *testing.T) {
+	authzPolicy := `{
+				"name": "authz",
+				"allow_rules":
+				[
+					{
+						"name": "allow_authenticated",
+						"source": {
+							"principals": ["*", ""]
+						}
+					}
+				]
+			}`
+	// Start a gRPC server with gRPC authz unary server interceptor.
+	i, _ := authz.NewStatic(authzPolicy)
+	creds, err := credentials.NewServerTLSFromFile(testdata.Path("x509/server1_cert.pem"), testdata.Path("x509/server1_key.pem"))
+	if err != nil {
+		t.Fatalf("failed to generate credentials: %v", err)
+	}
+
+	stub := &stubserver.StubServer{
+		UnaryCallF: func(context.Context, *testpb.SimpleRequest) (*testpb.SimpleResponse, error) {
+			return &testpb.SimpleResponse{}, nil
+		},
+		S: grpc.NewServer(grpc.Creds(creds), grpc.ChainUnaryInterceptor(i.UnaryInterceptor)),
+	}
+	stubserver.StartTestService(t, stub)
+	defer stub.S.Stop()
+
+	// Establish a connection to the server.
+	creds, err = credentials.NewClientTLSFromFile(testdata.Path("x509/server_ca_cert.pem"), "x.test.example.com")
+	if err != nil {
+		t.Fatalf("failed to load credentials: %v", err)
+	}
+	cc, err := grpc.NewClient(stub.Address, grpc.WithTransportCredentials(creds))
+	if err != nil {
+		t.Fatalf("grpc.NewClient(%v) failed: %v", stub.Address, err)
+	}
+	defer cc.Close()
+	client := testgrpc.NewTestServiceClient(cc)
+
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+
+	// Verifying authorization decision.
+	if _, err = client.UnaryCall(ctx, &testpb.SimpleRequest{}); err != nil {
+		t.Fatalf("client.UnaryCall(_, _) = %v; want nil", err)
+	}
+}
+
+func (s) TestAllowsRPCRequestWithPrincipalsFieldOnMTLSAuthenticatedConnection(t *testing.T) {
+	authzPolicy := `{
+				"name": "authz",
+				"allow_rules":
+				[
+					{
+						"name": "allow_authenticated",
+						"source": {
+							"principals": ["*", ""]
+						}
+					}
+				]
+			}`
+	// Start a gRPC server with gRPC authz unary server interceptor.
+	i, _ := authz.NewStatic(authzPolicy)
+	cert, err := tls.LoadX509KeyPair(testdata.Path("x509/server1_cert.pem"), testdata.Path("x509/server1_key.pem"))
+	if err != nil {
+		t.Fatalf("tls.LoadX509KeyPair(x509/server1_cert.pem, x509/server1_key.pem) failed: %v", err)
+	}
+	ca, err := os.ReadFile(testdata.Path("x509/client_ca_cert.pem"))
+	if err != nil {
+		t.Fatalf("os.ReadFile(x509/client_ca_cert.pem) failed: %v", err)
+	}
+	certPool := x509.NewCertPool()
+	if !certPool.AppendCertsFromPEM(ca) {
+		t.Fatal("failed to append certificates")
+	}
+	creds := credentials.NewTLS(&tls.Config{
+		ClientAuth:   tls.RequireAndVerifyClientCert,
+		Certificates: []tls.Certificate{cert},
+		ClientCAs:    certPool,
+	})
+	stub := &stubserver.StubServer{
+		UnaryCallF: func(context.Context, *testpb.SimpleRequest) (*testpb.SimpleResponse, error) {
+			return &testpb.SimpleResponse{}, nil
+		},
+		S: grpc.NewServer(grpc.Creds(creds), grpc.ChainUnaryInterceptor(i.UnaryInterceptor)),
+	}
+	stubserver.StartTestService(t, stub)
+	defer stub.Stop()
+
+	// Establish a connection to the server.
+	cert, err = tls.LoadX509KeyPair(testdata.Path("x509/client1_cert.pem"), testdata.Path("x509/client1_key.pem"))
+	if err != nil {
+		t.Fatalf("tls.LoadX509KeyPair(x509/client1_cert.pem, x509/client1_key.pem) failed: %v", err)
+	}
+	ca, err = os.ReadFile(testdata.Path("x509/server_ca_cert.pem"))
+	if err != nil {
+		t.Fatalf("os.ReadFile(x509/server_ca_cert.pem) failed: %v", err)
+	}
+	roots := x509.NewCertPool()
+	if !roots.AppendCertsFromPEM(ca) {
+		t.Fatal("failed to append certificates")
+	}
+	creds = credentials.NewTLS(&tls.Config{
+		Certificates: []tls.Certificate{cert},
+		RootCAs:      roots,
+		ServerName:   "x.test.example.com",
+	})
+	cc, err := grpc.NewClient(stub.Address, grpc.WithTransportCredentials(creds))
+	if err != nil {
+		t.Fatalf("grpc.NewClient(%v) failed: %v", stub.Address, err)
+	}
+	defer cc.Close()
+	client := testgrpc.NewTestServiceClient(cc)
+
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+
+	// Verifying authorization decision.
+	if _, err = client.UnaryCall(ctx, &testpb.SimpleRequest{}); err != nil {
+		t.Fatalf("client.UnaryCall(_, _) = %v; want nil", err)
+	}
+}
+
+func (s) TestFileWatcherEnd2End(t *testing.T) {
+	for name, test := range authzTests {
+		t.Run(name, func(t *testing.T) {
+			file := createTmpPolicyFile(t, name, []byte(test.authzPolicy))
+			i, _ := authz.NewFileWatcher(file, 1*time.Second)
+			defer i.Close()
+
+			stub := &stubserver.StubServer{
+				UnaryCallF: func(context.Context, *testpb.SimpleRequest) (*testpb.SimpleResponse, error) {
+					return &testpb.SimpleResponse{}, nil
+				},
+				StreamingInputCallF: func(stream testgrpc.TestService_StreamingInputCallServer) error {
+					for {
+						_, err := stream.Recv()
+						if err == io.EOF {
+							return stream.SendAndClose(&testpb.StreamingInputCallResponse{})
+						}
+						if err != nil {
+							return err
+						}
+					}
+				},
+				// Start a gRPC server with gRPC authz unary and stream server interceptors.
+				S: grpc.NewServer(grpc.ChainUnaryInterceptor(i.UnaryInterceptor), grpc.ChainStreamInterceptor(i.StreamInterceptor)),
+			}
+			stubserver.StartTestService(t, stub)
+			defer stub.Stop()
+
+			// Establish a connection to the server.
+			cc, err := grpc.NewClient(stub.Address, grpc.WithTransportCredentials(insecure.NewCredentials()))
+			if err != nil {
+				t.Fatalf("grpc.NewClient(%v) failed: %v", stub.Address, err)
+			}
+			defer cc.Close()
+			client := testgrpc.NewTestServiceClient(cc)
+
+			ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+			defer cancel()
+			ctx = metadata.NewOutgoingContext(ctx, test.md)
+
+			// Verifying authorization decision for Unary RPC.
+			_, err = client.UnaryCall(ctx, &testpb.SimpleRequest{})
+			if got := status.Convert(err); got.Code() != test.wantStatus.Code() || got.Message() != test.wantStatus.Message() {
+				t.Fatalf("[UnaryCall] error want:{%v} got:{%v}", test.wantStatus.Err(), got.Err())
+			}
+
+			// Verifying authorization decision for Streaming RPC.
+			stream, err := client.StreamingInputCall(ctx)
+			if err != nil {
+				t.Fatalf("failed StreamingInputCall : %v", err)
+			}
+			req := &testpb.StreamingInputCallRequest{
+				Payload: &testpb.Payload{
+					Body: []byte("hi"),
+				},
+			}
+			if err := stream.Send(req); err != nil && err != io.EOF {
+				t.Fatalf("failed stream.Send : %v", err)
+			}
+			_, err = stream.CloseAndRecv()
+			if got := status.Convert(err); got.Code() != test.wantStatus.Code() || got.Message() != test.wantStatus.Message() {
+				t.Fatalf("[StreamingCall] error want:{%v} got:{%v}", test.wantStatus.Err(), got.Err())
+			}
+		})
+	}
+}
+
+func retryUntil(ctx context.Context, tsc testgrpc.TestServiceClient, want *status.Status) (lastErr error) {
+	for ctx.Err() == nil {
+		_, lastErr = tsc.UnaryCall(ctx, &testpb.SimpleRequest{})
+		if s := status.Convert(lastErr); s.Code() == want.Code() && s.Message() == want.Message() {
+			return nil
+		}
+		time.Sleep(20 * time.Millisecond)
+	}
+	return lastErr
+}
+
+func (s) TestFileWatcher_ValidPolicyRefresh(t *testing.T) {
+	valid1 := authzTests["DeniesRPCMatchInDenyAndAllow"]
+	file := createTmpPolicyFile(t, "valid_policy_refresh", []byte(valid1.authzPolicy))
+	i, _ := authz.NewFileWatcher(file, 100*time.Millisecond)
+	defer i.Close()
+
+	stub := &stubserver.StubServer{
+		UnaryCallF: func(context.Context, *testpb.SimpleRequest) (*testpb.SimpleResponse, error) {
+			return &testpb.SimpleResponse{}, nil
+		},
+		// Start a gRPC server with gRPC authz unary server interceptor.
+		S: grpc.NewServer(grpc.ChainUnaryInterceptor(i.UnaryInterceptor)),
+	}
+	stubserver.StartTestService(t, stub)
+	defer stub.Stop()
+
+	// Establish a connection to the server.
+	cc, err := grpc.NewClient(stub.Address, grpc.WithTransportCredentials(insecure.NewCredentials()))
+	if err != nil {
+		t.Fatalf("grpc.NewClient(%v) failed: %v", stub.Address, err)
+	}
+	defer cc.Close()
+	client := testgrpc.NewTestServiceClient(cc)
+
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+
+	// Verifying authorization decision.
+	_, err = client.UnaryCall(ctx, &testpb.SimpleRequest{})
+	if got := status.Convert(err); got.Code() != valid1.wantStatus.Code() || got.Message() != valid1.wantStatus.Message() {
+		t.Fatalf("client.UnaryCall(_, _) = %v; want = %v", got.Err(), valid1.wantStatus.Err())
+	}
+
+	// Rewrite the file with a different valid authorization policy.
+	valid2 := authzTests["AllowsRPCEmptyDenyMatchInAllow"]
+	if err := os.WriteFile(file, []byte(valid2.authzPolicy), os.ModePerm); err != nil {
+		t.Fatalf("os.WriteFile(%q) failed: %v", file, err)
+	}
+
+	// Verifying authorization decision.
+	if got := retryUntil(ctx, client, valid2.wantStatus); got != nil {
+		t.Fatalf("client.UnaryCall(_, _) = %v; want = %v", got, valid2.wantStatus.Err())
+	}
+}
+
+func (s) TestFileWatcher_InvalidPolicySkipReload(t *testing.T) {
+	valid := authzTests["DeniesRPCMatchInDenyAndAllow"]
+	file := createTmpPolicyFile(t, "invalid_policy_skip_reload", []byte(valid.authzPolicy))
+	i, _ := authz.NewFileWatcher(file, 20*time.Millisecond)
+	defer i.Close()
+
+	stub := &stubserver.StubServer{
+		UnaryCallF: func(context.Context, *testpb.SimpleRequest) (*testpb.SimpleResponse, error) {
+			return &testpb.SimpleResponse{}, nil
+		},
+		// Start a gRPC server with gRPC authz unary server interceptors.
+		S: grpc.NewServer(grpc.ChainUnaryInterceptor(i.UnaryInterceptor)),
+	}
+	stubserver.StartTestService(t, stub)
+	defer stub.Stop()
+
+	// Establish a connection to the server.
+	cc, err := grpc.NewClient(stub.Address, grpc.WithTransportCredentials(insecure.NewCredentials()))
+	if err != nil {
+		t.Fatalf("grpc.NewClient(%v) failed: %v", stub.Address, err)
+	}
+	defer cc.Close()
+	client := testgrpc.NewTestServiceClient(cc)
+
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+
+	// Verifying authorization decision.
+	_, err = client.UnaryCall(ctx, &testpb.SimpleRequest{})
+	if got := status.Convert(err); got.Code() != valid.wantStatus.Code() || got.Message() != valid.wantStatus.Message() {
+		t.Fatalf("client.UnaryCall(_, _) = %v; want = %v", got.Err(), valid.wantStatus.Err())
+	}
+
+	// Skips the invalid policy update, and continues to use the valid policy.
+	if err := os.WriteFile(file, []byte("{}"), os.ModePerm); err != nil {
+		t.Fatalf("os.WriteFile(%q) failed: %v", file, err)
+	}
+
+	// Wait 40 ms for background go routine to read updated files.
+	time.Sleep(40 * time.Millisecond)
+
+	// Verifying authorization decision.
+	_, err = client.UnaryCall(ctx, &testpb.SimpleRequest{})
+	if got := status.Convert(err); got.Code() != valid.wantStatus.Code() || got.Message() != valid.wantStatus.Message() {
+		t.Fatalf("client.UnaryCall(_, _) = %v; want = %v", got.Err(), valid.wantStatus.Err())
+	}
+}
+
+func (s) TestFileWatcher_RecoversFromReloadFailure(t *testing.T) {
+	valid1 := authzTests["DeniesRPCMatchInDenyAndAllow"]
+	file := createTmpPolicyFile(t, "recovers_from_reload_failure", []byte(valid1.authzPolicy))
+	i, _ := authz.NewFileWatcher(file, 100*time.Millisecond)
+	defer i.Close()
+
+	stub := &stubserver.StubServer{
+		UnaryCallF: func(context.Context, *testpb.SimpleRequest) (*testpb.SimpleResponse, error) {
+			return &testpb.SimpleResponse{}, nil
+		},
+		S: grpc.NewServer(grpc.ChainUnaryInterceptor(i.UnaryInterceptor)),
+	}
+	stubserver.StartTestService(t, stub)
+	defer stub.Stop()
+
+	// Establish a connection to the server.
+	cc, err := grpc.NewClient(stub.Address, grpc.WithTransportCredentials(insecure.NewCredentials()))
+	if err != nil {
+		t.Fatalf("grpc.NewClient(%v) failed: %v", stub.Address, err)
+	}
+	defer cc.Close()
+	client := testgrpc.NewTestServiceClient(cc)
+
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+
+	// Verifying authorization decision.
+	_, err = client.UnaryCall(ctx, &testpb.SimpleRequest{})
+	if got := status.Convert(err); got.Code() != valid1.wantStatus.Code() || got.Message() != valid1.wantStatus.Message() {
+		t.Fatalf("client.UnaryCall(_, _) = %v; want = %v", got.Err(), valid1.wantStatus.Err())
+	}
+
+	// Skips the invalid policy update, and continues to use the valid policy.
+	if err := os.WriteFile(file, []byte("{}"), os.ModePerm); err != nil {
+		t.Fatalf("os.WriteFile(%q) failed: %v", file, err)
+	}
+
+	// Wait 120 ms for background go routine to read updated files.
+	time.Sleep(120 * time.Millisecond)
+
+	// Verifying authorization decision.
+	_, err = client.UnaryCall(ctx, &testpb.SimpleRequest{})
+	if got := status.Convert(err); got.Code() != valid1.wantStatus.Code() || got.Message() != valid1.wantStatus.Message() {
+		t.Fatalf("client.UnaryCall(_, _) = %v; want = %v", got.Err(), valid1.wantStatus.Err())
+	}
+
+	// Rewrite the file with a different valid authorization policy.
+	valid2 := authzTests["AllowsRPCEmptyDenyMatchInAllow"]
+	if err := os.WriteFile(file, []byte(valid2.authzPolicy), os.ModePerm); err != nil {
+		t.Fatalf("os.WriteFile(%q) failed: %v", file, err)
+	}
+
+	// Verifying authorization decision.
+	if got := retryUntil(ctx, client, valid2.wantStatus); got != nil {
+		t.Fatalf("client.UnaryCall(_, _) = %v; want = %v", got, valid2.wantStatus.Err())
+	}
+}