grpc: Fix cardinality violations in non-client streaming RPCs.

server.go

@@ -1598,6 +1598,7 @@ func (s *Server) processStreamingRPC(ctx context.Context, stream *transport.Serv
 		s:                     stream,
 		p:                     &parser{r: stream, bufferPool: s.opts.bufferPool},
 		codec:                 s.getCodec(stream.ContentSubtype()),
+		desc:                  sd,
 		maxReceiveMessageSize: s.opts.maxReceiveMessageSize,
 		maxSendMessageSize:    s.opts.maxSendMessageSize,
 		trInfo:                trInfo,

stream.go

@@ -1580,6 +1580,7 @@ type serverStream struct {
 	s     *transport.ServerStream
 	p     *parser
 	codec baseCodec
+	desc  *StreamDesc
 
 	compressorV0   Compressor
 	compressorV1   encoding.Compressor
@@ -1774,6 +1775,9 @@ func (ss *serverStream) RecvMsg(m any) (err error) {
 					binlog.Log(ss.ctx, chc)
 				}
 			}
+			if !ss.desc.ClientStreams {
+				return status.Errorf(codes.Internal, "RecvMsg is called twice")
+			}
 			return err
 		}
 		if err == io.ErrUnexpectedEOF {

test/end2end_test.go

@@ -3740,6 +3740,232 @@ func (s) TestClientStreaming_ReturnErrorAfterSendAndClose(t *testing.T) {
 	}
 }
 
+// Tests the behavior for server-side streaming when server call
+// RecvMsg twice. Second call to RecvMsg should fail with Internal
+// error.
+func (s) TestServerStreaming_ServerCallRecvMsgTwice(t *testing.T) {
+	lis, err := testutils.LocalTCPListener()
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer lis.Close()
+
+	s := grpc.NewServer()
+	serviceDesc := grpc.ServiceDesc{
+		ServiceName: "grpc.testing.TestService",
+		HandlerType: (*any)(nil),
+		Methods:     []grpc.MethodDesc{},
+		Streams: []grpc.StreamDesc{
+			{
+				StreamName: "FullDuplexCall",
+				Handler: func(srv interface{}, stream grpc.ServerStream) error {
+					err := stream.RecvMsg(&testpb.Empty{})
+					if err != nil {
+						t.Errorf("stream.RecvMsg() = %v, want <nil>", err)
+					}
+
+					if err = stream.RecvMsg(&testpb.Empty{}); status.Code(err) != codes.Internal {
+						t.Errorf("stream.RecvMsg() = %v, want error %v", status.Code(err), codes.Internal)
+					}
+					return nil
+				},
+				ClientStreams: false,
+				ServerStreams: true,
+			},
+		},
+		Metadata: "grpc/testing/test.proto",
+	}
+	s.RegisterService(&serviceDesc, &testServer{})
+	go s.Serve(lis)
+	defer s.Stop()
+
+	ctx, cancel := context.WithTimeout(context.Background(), defaultTestTimeout)
+	defer cancel()
+	cc, err := grpc.NewClient(lis.Addr().String(), grpc.WithTransportCredentials(insecure.NewCredentials()))
+	if err != nil {
+		t.Fatalf("grpc.NewClient(%q) failed unexpectedly: %v", lis.Addr(), err)
+	}
+	defer cc.Close()
+
+	desc := &grpc.StreamDesc{
+		StreamName:    "FullDuplexCall",
+		ServerStreams: true,
+		ClientStreams: false, // This is the test case: client is *not* allowed to stream
+	}
+
+	stream, err := cc.NewStream(ctx, desc, "/grpc.testing.TestService/FullDuplexCall")
+	if err != nil {
+		t.Fatalf("cc.NewStream() failed unexpectedly: %v", err)
+	}
+
+	if err := stream.SendMsg(&testpb.Empty{}); err != nil {
+		t.Errorf("stream.SendMsg() = %v, want <nil>", err)
+	}
+
+	if err := stream.RecvMsg(&testpb.Empty{}); status.Code(err) != codes.Internal {
+		t.Errorf("stream.RecvMsg() = %v, want error %v", status.Code(err), codes.Internal)
+	}
+}
+
+// Tests the behavior for server-side streaming when client call
+// SendMsg twice. Second call to SendMsg should fail with Internal
+// error.
+func (s) TestServerStreaming_ClientCallSendMsgTwice(t *testing.T) {
+	lis, err := testutils.LocalTCPListener()
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer lis.Close()
+
+	ss := grpc.UnknownServiceHandler(func(any, grpc.ServerStream) error {
+		return nil
+	})
+
+	s := grpc.NewServer(ss)
+	go s.Serve(lis)
+	defer s.Stop()
+
+	ctx, cancel := context.WithTimeout(context.Background(), defaultTestTimeout)
+	defer cancel()
+	cc, err := grpc.NewClient(lis.Addr().String(), grpc.WithTransportCredentials(insecure.NewCredentials()))
+	if err != nil {
+		t.Fatalf("grpc.NewClient(%q) failed unexpectedly: %v", lis.Addr(), err)
+	}
+	defer cc.Close()
+
+	desc := &grpc.StreamDesc{
+		StreamName:    "FullDuplexCall",
+		ServerStreams: true,
+		ClientStreams: false,
+	}
+
+	stream, err := cc.NewStream(ctx, desc, "/grpc.testing.TestService/FullDuplexCall")
+	if err != nil {
+		t.Fatalf("cc.NewStream() failed unexpectedly: %v", err)
+	}
+
+	if err := stream.SendMsg(&testpb.Empty{}); err != nil {
+		t.Errorf("stream.SendMsg() = %v, want <nil>", err)
+	}
+
+	if err := stream.SendMsg(&testpb.Empty{}); status.Code(err) != codes.Internal {
+		t.Errorf("stream.SendMsg() = %v, want error %v", status.Code(err), codes.Internal)
+	}
+}
+
+// Tests the behavior for unary RPC when server call
+// RecvMsg twice. Second call to RecvMsg should fail with Internal
+// error.
+func (s) TestUnaryRPC_ServerCallRecvMsgTwice(t *testing.T) {
+	lis, err := testutils.LocalTCPListener()
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer lis.Close()
+
+	s := grpc.NewServer()
+	serviceDesc := grpc.ServiceDesc{
+		ServiceName: "grpc.testing.TestService",
+		HandlerType: (*any)(nil),
+		Methods:     []grpc.MethodDesc{},
+		Streams: []grpc.StreamDesc{
+			{
+				StreamName: "UnaryCall",
+				Handler: func(srv interface{}, stream grpc.ServerStream) error {
+					err := stream.RecvMsg(&testpb.Empty{})
+					if err != nil {
+						t.Errorf("stream.RecvMsg() = %v, want <nil>", err)
+					}
+
+					if err = stream.RecvMsg(&testpb.Empty{}); status.Code(err) != codes.Internal {
+						t.Errorf("stream.RecvMsg() = %v, want error %v", status.Code(err), codes.Internal)
+					}
+					return nil
+				},
+				ClientStreams: false,
+				ServerStreams: false,
+			},
+		},
+		Metadata: "grpc/testing/test.proto",
+	}
+	s.RegisterService(&serviceDesc, &testServer{})
+	go s.Serve(lis)
+	defer s.Stop()
+
+	ctx, cancel := context.WithTimeout(context.Background(), defaultTestTimeout)
+	defer cancel()
+	cc, err := grpc.NewClient(lis.Addr().String(), grpc.WithTransportCredentials(insecure.NewCredentials()))
+	if err != nil {
+		t.Fatalf("grpc.NewClient(%q) failed unexpectedly: %v", lis.Addr(), err)
+	}
+	defer cc.Close()
+
+	desc := &grpc.StreamDesc{
+		StreamName:    "UnaryCall",
+		ServerStreams: false,
+		ClientStreams: false,
+	}
+
+	stream, err := cc.NewStream(ctx, desc, "/grpc.testing.TestService/UnaryCall")
+	if err != nil {
+		t.Fatalf("cc.NewStream() failed unexpectedly: %v", err)
+	}
+
+	if err := stream.SendMsg(&testpb.Empty{}); err != nil {
+		t.Errorf("stream.SendMsg() = %v, want <nil>", err)
+	}
+
+	if err := stream.RecvMsg(&testpb.Empty{}); status.Code(err) != codes.Internal {
+		t.Errorf("stream.RecvMsg() = %v, want error %v", status.Code(err), codes.Internal)
+	}
+}
+
+// Tests the behavior for unary RPC when client call
+// SendMsg twice. Second call to SendMsg should fail with Internal
+// error.
+func (s) TestUnaryRPC_ClientCallSendMsgTwice(t *testing.T) {
+	lis, err := testutils.LocalTCPListener()
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer lis.Close()
+
+	ss := grpc.UnknownServiceHandler(func(any, grpc.ServerStream) error {
+		return nil
+	})
+
+	s := grpc.NewServer(ss)
+	go s.Serve(lis)
+	defer s.Stop()
+
+	ctx, cancel := context.WithTimeout(context.Background(), defaultTestTimeout)
+	defer cancel()
+	cc, err := grpc.NewClient(lis.Addr().String(), grpc.WithTransportCredentials(insecure.NewCredentials()))
+	if err != nil {
+		t.Fatalf("grpc.NewClient(%q) failed unexpectedly: %v", lis.Addr(), err)
+	}
+	defer cc.Close()
+
+	desc := &grpc.StreamDesc{
+		StreamName:    "UnaryCall",
+		ServerStreams: false,
+		ClientStreams: false,
+	}
+
+	stream, err := cc.NewStream(ctx, desc, "/grpc.testing.TestService/UnaryCall")
+	if err != nil {
+		t.Fatalf("cc.NewStream() failed unexpectedly: %v", err)
+	}
+
+	if err := stream.SendMsg(&testpb.Empty{}); err != nil {
+		t.Errorf("stream.SendMsg() = %v, want <nil>", err)
+	}
+
+	if err := stream.SendMsg(&testpb.Empty{}); status.Code(err) != codes.Internal {
+		t.Errorf("stream.SendMsg() = %v, want error %v", status.Code(err), codes.Internal)
+	}
+}
+
 // Tests that a client receives a cardinality violation error for client-streaming
 // RPCs if the server call SendMsg multiple times.
 func (s) TestClientStreaming_ServerHandlerSendMsgAfterSendMsg(t *testing.T) {