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
@@ -1588,6 +1589,8 @@ type serverStream struct {
 
 	sendCompressorName string
 
+	recvFirstMsg bool // set after the first message is received
+
 	maxReceiveMessageSize int
 	maxSendMessageSize    int
 	trInfo                *traceInfo
@@ -1774,13 +1777,18 @@ func (ss *serverStream) RecvMsg(m any) (err error) {
 					binlog.Log(ss.ctx, chc)
 				}
 			}
+			// Received no request msg for non-client streaming rpcs.
+			if !ss.desc.ClientStreams && !ss.recvFirstMsg {
+				return status.Error(codes.Internal, "cardinality violation: received no request message from non-client-streaming RPC")
+			}
 			return err
 		}
 		if err == io.ErrUnexpectedEOF {
 			err = status.Error(codes.Internal, io.ErrUnexpectedEOF.Error())
 		}
 		return toRPCErr(err)
 	}
+	ss.recvFirstMsg = true
 	if len(ss.statsHandler) != 0 {
 		for _, sh := range ss.statsHandler {
 			sh.HandleRPC(ss.s.Context(), &stats.InPayload{
@@ -1800,7 +1808,19 @@ func (ss *serverStream) RecvMsg(m any) (err error) {
 			binlog.Log(ss.ctx, cm)
 		}
 	}
-	return nil
+
+	if ss.desc.ClientStreams {
+		// Subsequent messages should be received by subsequent RecvMsg calls.
+		return nil
+	}
+	// Special handling for non-client-stream rpcs.
+	// This recv expects EOF or errors, so we don't collect inPayload.
+	if err := recv(ss.p, ss.codec, ss.s, ss.decompressorV0, m, ss.maxReceiveMessageSize, nil, ss.decompressorV1, true); err == io.EOF {
+		return nil
+	} else if err != nil {
+		return err
+	}
+	return status.Error(codes.Internal, "cardinality violation: received multiple request messages for non-client-streaming RPC")
 }
 
 // MethodFromServerStream returns the method string for the input stream.

test/end2end_test.go

@@ -3740,6 +3740,238 @@ func (s) TestClientStreaming_ReturnErrorAfterSendAndClose(t *testing.T) {
 	}
 }
 
+// Tests the behavior for server-side streaming when client calls SendMsg twice.
+// Second call to SendMsg should fail with Internal error and result in closing
+// the connection with a RST_STREAM.
+func (s) TestServerStreaming_ClientCallSendMsgTwice(t *testing.T) {
+	// To ensure server.recvMsg() is successfully completed.
+	recvDoneOnServer := make(chan struct{})
+	// To ensure goroutine for test does not end before RPC handler performs error
+	// checking.
+	handlerDone := make(chan struct{})
+	ss := stubserver.StubServer{
+		StreamingOutputCallF: func(_ *testpb.StreamingOutputCallRequest, stream testgrpc.TestService_StreamingOutputCallServer) error {
+			// The initial call to recvMsg is made by the generated code.
+			close(recvDoneOnServer)
+			<-stream.Context().Done()
+			if err := stream.SendMsg(&testpb.StreamingOutputCallRequest{}); status.Code(err) != codes.Canceled {
+				t.Errorf("stream.SendMsg() = %v, want error %v", err, codes.Canceled)
+			}
+			close(handlerDone)
+			return nil
+		},
+	}
+	if err := ss.Start(nil); err != nil {
+		t.Fatal("Error starting server:", err)
+	}
+	defer ss.Stop()
+
+	ctx, cancel := context.WithTimeout(context.Background(), defaultTestTimeout)
+	defer cancel()
+	cc, err := grpc.NewClient(ss.Address, grpc.WithTransportCredentials(insecure.NewCredentials()))
+	if err != nil {
+		t.Fatalf("grpc.NewClient(%q) failed unexpectedly: %v", ss.Address, err)
+	}
+	defer cc.Close()
+
+	desc := &grpc.StreamDesc{
+		StreamName:    "StreamingOutputCall",
+		ServerStreams: true,
+		ClientStreams: false,
+	}
+
+	stream, err := cc.NewStream(ctx, desc, "/grpc.testing.TestService/StreamingOutputCall")
+	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)
+	}
+	<-recvDoneOnServer
+	if err := stream.SendMsg(&testpb.Empty{}); status.Code(err) != codes.Internal {
+		t.Errorf("stream.SendMsg() = %v, want error %v", err, codes.Internal)
+	}
+	<-handlerDone
+}
+
+// Tests the behavior for unary RPC when client calls SendMsg twice. Second call
+// to SendMsg should fail with Internal error.
+func (s) TestUnaryRPC_ClientCallSendMsgTwice(t *testing.T) {
+	ss := stubserver.StubServer{
+		UnaryCallF: func(context.Context, *testpb.SimpleRequest) (*testpb.SimpleResponse, error) {
+			return &testpb.SimpleResponse{}, nil
+		},
+	}
+	if err := ss.Start(nil); err != nil {
+		t.Fatal("Error starting server:", err)
+	}
+	defer ss.Stop()
+
+	ctx, cancel := context.WithTimeout(context.Background(), defaultTestTimeout)
+	defer cancel()
+	cc, err := grpc.NewClient(ss.Address, grpc.WithTransportCredentials(insecure.NewCredentials()))
+	if err != nil {
+		t.Fatalf("grpc.NewClient(%q) failed unexpectedly: %v", ss.Address, 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 the behavior for server-side streaming RPC when client misbehaves as Bidi-streaming
+// and sends multiple messages.
+func (s) TestServerStreaming_ClientSendsMultipleMessages(t *testing.T) {
+	// The initial call to recvMsg made by the generated code, will return the error.
+	ss := stubserver.StubServer{}
+	if err := ss.Start(nil); err != nil {
+		t.Fatal("Error starting server:", err)
+	}
+	defer ss.Stop()
+
+	ctx, cancel := context.WithTimeout(context.Background(), defaultTestTimeout)
+	defer cancel()
+	cc, err := grpc.NewClient(ss.Address, grpc.WithTransportCredentials(insecure.NewCredentials()))
+	if err != nil {
+		t.Fatalf("grpc.NewClient(%q) failed unexpectedly: %v", ss.Address, err)
+	}
+	defer cc.Close()
+
+	// Making the client bi-di to bypass the client side checks that stop a non-streaming client
+	// from sending multiple messages.
+	desc := &grpc.StreamDesc{
+		StreamName:    "StreamingOutputCall",
+		ServerStreams: true,
+		ClientStreams: true,
+	}
+
+	stream, err := cc.NewStream(ctx, desc, "/grpc.testing.TestService/StreamingOutputCall")
+	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{}); 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 of server for server-side streaming RPC when client sends zero request messages.
+func (s) TestServerStreaming_ServerRecvZeroRequests(t *testing.T) {
+	testCases := []struct {
+		name     string
+		desc     *grpc.StreamDesc
+		wantCode codes.Code
+	}{
+		{
+			name: "BidiStreaming",
+			desc: &grpc.StreamDesc{
+				StreamName:    "StreamingOutputCall",
+				ServerStreams: true,
+				ClientStreams: true,
+			},
+			wantCode: codes.Internal,
+		},
+		{
+			name: "ClientStreaming",
+			desc: &grpc.StreamDesc{
+				StreamName:    "StreamingOutputCall",
+				ServerStreams: false,
+				ClientStreams: true,
+			},
+			wantCode: codes.Internal,
+		},
+	}
+
+	for _, tc := range testCases {
+		// The initial call to recvMsg made by the generated code, will return the error.
+		ss := stubserver.StubServer{}
+		if err := ss.Start(nil); err != nil {
+			t.Fatal("Error starting server:", err)
+		}
+		defer ss.Stop()
+
+		ctx, cancel := context.WithTimeout(context.Background(), defaultTestTimeout)
+		defer cancel()
+		cc, err := grpc.NewClient(ss.Address, grpc.WithTransportCredentials(insecure.NewCredentials()))
+		if err != nil {
+			t.Fatalf("grpc.NewClient(%q) failed unexpectedly: %v", ss.Address, err)
+		}
+		defer cc.Close()
+
+		stream, err := cc.NewStream(ctx, tc.desc, "/grpc.testing.TestService/StreamingOutputCall")
+		if err != nil {
+			t.Fatalf("cc.NewStream() failed unexpectedly: %v", err)
+		}
+
+		if err := stream.CloseSend(); err != nil {
+			t.Errorf("stream.CloseSend() = %v, want <nil>", err)
+		}
+
+		if err := stream.RecvMsg(&testpb.Empty{}); status.Code(err) != tc.wantCode {
+			t.Errorf("stream.RecvMsg() = %v, want error %v", status.Code(err), tc.wantCode)
+		}
+	}
+}
+
+// Tests the behavior of client for server-side streaming RPC when client sends zero request messages.
+func (s) TestServerStreaming_ClientSendsZeroRequests(t *testing.T) {
+	t.Skip()
+	// The initial call to recvMsg made by the generated code, will return the error.
+	ss := stubserver.StubServer{}
+	if err := ss.Start(nil); err != nil {
+		t.Fatal("Error starting server:", err)
+	}
+	defer ss.Stop()
+
+	ctx, cancel := context.WithTimeout(context.Background(), defaultTestTimeout)
+	defer cancel()
+	cc, err := grpc.NewClient(ss.Address, grpc.WithTransportCredentials(insecure.NewCredentials()))
+	if err != nil {
+		t.Fatalf("grpc.NewClient(%q) failed unexpectedly: %v", ss.Address, err)
+	}
+	defer cc.Close()
+
+	desc := &grpc.StreamDesc{
+		StreamName:    "StreamingOutputCall",
+		ServerStreams: true,
+		ClientStreams: false,
+	}
+
+	stream, err := cc.NewStream(ctx, desc, "/grpc.testing.TestService/StreamingOutputCall")
+	if err != nil {
+		t.Fatalf("cc.NewStream() failed unexpectedly: %v", err)
+	}
+
+	if err := stream.CloseSend(); status.Code(err) != codes.Internal {
+		t.Errorf("stream.CloseSend() = %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) {