fix(pool): enforce stratum line limits

Co-Authored-By: Virgil <virgil@lethean.io>

pool/client.go

@@ -205,13 +205,17 @@ func (c *StratumClient) writeJSON(value interface{}) error {
 }
 
 func (c *StratumClient) readLoop() {
-	reader := bufio.NewReader(c.conn)
+	reader := bufio.NewReaderSize(c.conn, 16384)
 	for {
-		line, errorValue := reader.ReadBytes('\n')
+		line, isPrefix, errorValue := reader.ReadLine()
 		if errorValue != nil {
 			c.notifyDisconnect()
 			return
 		}
+		if isPrefix {
+			c.notifyDisconnect()
+			return
+		}
 
 		response := jsonRPCResponse{}
 		if errorValue = json.Unmarshal(line, &response); errorValue != nil {

pool/client_test.go

@@ -31,6 +31,43 @@ func (l *disconnectCountingListener) Count() int {
 	return l.count
 }
 
+func TestStratumClient_ReadLoop_Ugly(t *testing.T) {
+	serverConn, clientConn := net.Pipe()
+	defer clientConn.Close()
+
+	listener := &disconnectCountingListener{}
+	client := &StratumClient{
+		listener: listener,
+		conn:     serverConn,
+	}
+
+	go client.readLoop()
+
+	payload := make([]byte, 16385)
+	for index := range payload {
+		payload[index] = 'a'
+	}
+	payload = append(payload, '\n')
+	writeErr := make(chan error, 1)
+	go func() {
+		_, err := clientConn.Write(payload)
+		writeErr <- err
+	}()
+
+	time.Sleep(50 * time.Millisecond)
+	if got := listener.Count(); got != 1 {
+		t.Fatalf("expected oversized line to close the connection, got %d disconnect callbacks", got)
+	}
+
+	select {
+	case err := <-writeErr:
+		if err != nil {
+			t.Fatal(err)
+		}
+	default:
+	}
+}
+
 func TestStratumClient_Disconnect_Good(t *testing.T) {
 	serverConn, clientConn := net.Pipe()
 	defer clientConn.Close()