From 9c298e4851217edb363d515db7e823b97a107ec2 Mon Sep 17 00:00:00 2001
From: Igor Postelnik <igor@cloudflare.com>
Date: Wed, 3 Feb 2021 13:00:55 -0600
Subject: [PATCH] TUN-3855: Add ability to override target of 'access ssh'
 command to a different host for testing

---
 carrier/carrier.go                |  7 +++++--
 carrier/websocket.go              |  8 +++++++-
 cmd/cloudflared/access/carrier.go | 22 ++++++++++++++++++++++
 cmd/cloudflared/access/cmd.go     |  8 +++++++-
 4 files changed, 41 insertions(+), 4 deletions(-)

diff --git a/carrier/carrier.go b/carrier/carrier.go
index a3787c4d..771dab9e 100644
--- a/carrier/carrier.go
+++ b/carrier/carrier.go
@@ -4,6 +4,7 @@
 package carrier
 
 import (
+	"crypto/tls"
 	"io"
 	"net"
 	"net/http"
@@ -20,8 +21,10 @@ import (
 const LogFieldOriginURL = "originURL"
 
 type StartOptions struct {
-	OriginURL string
-	Headers   http.Header
+	OriginURL       string
+	Headers         http.Header
+	Host            string
+	TLSClientConfig *tls.Config
 }
 
 // Connection wraps up all the needed functions to forward over the tunnel
diff --git a/carrier/websocket.go b/carrier/websocket.go
index 704d3d5c..7a5976fa 100644
--- a/carrier/websocket.go
+++ b/carrier/websocket.go
@@ -82,11 +82,17 @@ func createWebsocketStream(options *StartOptions, log *zerolog.Logger) (*cfwebso
 		return nil, err
 	}
 	req.Header = options.Headers
+	if options.Host != "" {
+		req.Host = options.Host
+	}
 
 	dump, err := httputil.DumpRequest(req, false)
 	log.Debug().Msgf("Websocket request: %s", string(dump))
 
-	wsConn, resp, err := cfwebsocket.ClientConnect(req, nil)
+	dialer := &websocket.Dialer{
+		TLSClientConfig: options.TLSClientConfig,
+	}
+	wsConn, resp, err := cfwebsocket.ClientConnect(req, dialer)
 	defer closeRespBody(resp)
 
 	if err != nil && IsAccessResponse(resp) {
diff --git a/cmd/cloudflared/access/carrier.go b/cmd/cloudflared/access/carrier.go
index b775ca92..c0fdaf71 100644
--- a/cmd/cloudflared/access/carrier.go
+++ b/cmd/cloudflared/access/carrier.go
@@ -1,6 +1,8 @@
 package access
 
 import (
+	"crypto/tls"
+	"fmt"
 	"net/http"
 	"strings"
 
@@ -84,6 +86,26 @@ func ssh(c *cli.Context) error {
 	options := &carrier.StartOptions{
 		OriginURL: originURL,
 		Headers:   headers,
+		Host:      hostname,
+	}
+
+	if connectTo := c.String(sshConnectTo); connectTo != "" {
+		parts := strings.Split(connectTo, ":")
+		switch len(parts) {
+		case 1:
+			options.OriginURL = fmt.Sprintf("https://%s", parts[0])
+		case 2:
+			options.OriginURL = fmt.Sprintf("https://%s:%s", parts[0], parts[1])
+		case 3:
+			options.OriginURL = fmt.Sprintf("https://%s:%s", parts[2], parts[1])
+			options.TLSClientConfig = &tls.Config{
+				InsecureSkipVerify: true,
+				ServerName: parts[0],
+			}
+			log.Warn().Msgf("Using insecure SSL connection because SNI overridden to %s", parts[0])
+		default:
+			return fmt.Errorf("invalid connection override: %s", connectTo)
+		}
 	}
 
 	// we could add a cmd line variable for this bool if we want the SOCK5 server to be on the client side
diff --git a/cmd/cloudflared/access/cmd.go b/cmd/cloudflared/access/cmd.go
index f9049c69..e622aad8 100644
--- a/cmd/cloudflared/access/cmd.go
+++ b/cmd/cloudflared/access/cmd.go
@@ -33,6 +33,7 @@ const (
 	sshTokenIDFlag     = "service-token-id"
 	sshTokenSecretFlag = "service-token-secret"
 	sshGenCertFlag     = "short-lived-cert"
+	sshConnectTo       = "connect-to"
 	sshConfigTemplate  = `
 Add to your {{.Home}}/.ssh/config:
 
@@ -54,7 +55,7 @@ Host cfpipe-{{.Hostname}}
 const sentryDSN = "https://56a9c9fa5c364ab28f34b14f35ea0f1b@sentry.io/189878"
 
 var (
-	shutdownC      chan struct{}
+	shutdownC chan struct{}
 )
 
 // Init will initialize and store vars from the main program
@@ -164,6 +165,11 @@ func Commands() []*cli.Command {
 							Aliases: []string{"loglevel"}, //added to match the tunnel side
 							Usage:   "Application logging level {fatal, error, info, debug}. ",
 						},
+						&cli.StringFlag{
+							Name:  sshConnectTo,
+							Hidden: true,
+							Usage: "Connect to alternate location for testing, value is host, host:port, or sni:port:host",
+						},
 					},
 				},
 				{