Prevent SetDeadline, SetReadDeadline and SetWriteDeadline from setting up unlimited deadline, and also impose our own timeout retry mechanism.

application/server/conn.go

@@ -0,0 +1,89 @@
+// Sshwifty - A Web SSH client
+//
+// Copyright (C) 2019 Rui NI <nirui@gmx.com>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+package server
+
+import (
+	"net"
+	"time"
+
+	"github.com/niruix/sshwifty/application/network"
+)
+
+var (
+	emptyTime = time.Time{}
+)
+
+type listener struct {
+	*net.TCPListener
+
+	readTimeout  time.Duration
+	writeTimeout time.Duration
+}
+
+func (l listener) Accept() (net.Conn, error) {
+	acc, accErr := l.TCPListener.Accept()
+
+	if accErr != nil {
+		return nil, accErr
+	}
+
+	timeoutConn := network.NewTimeoutConn(acc, l.readTimeout, l.writeTimeout)
+
+	return conn{
+		TimeoutConn:  &timeoutConn,
+		readTimeout:  l.readTimeout,
+		writeTimeout: l.writeTimeout,
+	}, nil
+}
+
+// conn is a net.Conn hack, we use it prevent the upper to alter some important
+// configuration of the connection, mainly the timeouts.
+type conn struct {
+	*network.TimeoutConn
+
+	readTimeout  time.Duration
+	writeTimeout time.Duration
+}
+
+func (c conn) normalizeTimeout(t time.Time, m time.Duration) time.Time {
+	max := time.Now().Add(m)
+
+	// You cannot set timeout that is longer than the given m
+	if t.After(max) {
+		return max
+	}
+
+	return t
+}
+
+func (c conn) SetDeadline(dl time.Time) error {
+	c.SetReadDeadline(dl)
+	c.SetWriteDeadline(dl)
+
+	return nil
+}
+
+func (c conn) SetReadDeadline(dl time.Time) error {
+	return c.TimeoutConn.SetReadDeadline(
+		c.normalizeTimeout(dl, c.readTimeout))
+}
+
+func (c conn) SetWriteDeadline(dl time.Time) error {
+	return c.TimeoutConn.SetWriteDeadline(
+		c.normalizeTimeout(dl, c.writeTimeout))
+}

application/server/server.go

@@ -26,6 +26,7 @@ import (
 	"net/http"
 	"strconv"
 	"sync"
+	"time"
 
 	"github.com/niruix/sshwifty/application/configuration"
 	"github.com/niruix/sshwifty/application/log"
@@ -111,11 +112,15 @@ func (s Server) Wait() {
 }
 
 func (s *Serving) buildListener(
-	ip string, port uint16) (*net.TCPListener, error) {
+	ip string,
+	port uint16,
+	readTimeout time.Duration,
+	writeTimeout time.Duration,
+) (listener, error) {
 	ipAddr := net.ParseIP(ip)
 
 	if ipAddr == nil {
-		return nil, ErrInvalidIPAddress
+		return listener{}, ErrInvalidIPAddress
 	}
 
 	ipPort := net.JoinHostPort(
@@ -124,10 +129,20 @@ func (s *Serving) buildListener(
 	addr, addrErr := net.ResolveTCPAddr("tcp", ipPort)
 
 	if addrErr != nil {
-		return nil, addrErr
+		return listener{}, addrErr
 	}
 
-	return net.ListenTCP("tcp", addr)
+	ll, llErr := net.ListenTCP("tcp", addr)
+
+	if llErr != nil {
+		return listener{}, llErr
+	}
+
+	return listener{
+		TCPListener:  ll,
+		readTimeout:  readTimeout,
+		writeTimeout: writeTimeout,
+	}, nil
 }
 
 // run starts the server
@@ -137,7 +152,6 @@ func (s *Serving) run(
 	closeCallback CloseCallback,
 ) error {
 	var err error
-	var ls *net.TCPListener
 
 	defer func() {
 		if err == nil || err == http.ErrServerClosed {
@@ -151,7 +165,12 @@ func (s *Serving) run(
 		closeCallback(err)
 	}()
 
-	ls, err = s.buildListener(cfg.ListenInterface, cfg.ListenPort)
+	ls, err := s.buildListener(
+		cfg.ListenInterface,
+		cfg.ListenPort,
+		cfg.ReadTimeout,
+		cfg.WriteTimeout,
+	)
 
 	if err != nil {
 		return err