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))
+}