From 0a5596290c8b5adc42c46c0a375d4b970230b550 Mon Sep 17 00:00:00 2001
From: Luke Shumaker <lukeshu@sbcglobal.net>
Date: Mon, 21 Nov 2016 14:26:43 -0500
Subject: tls-getcerts: add xmpp <starttls> support

---
 tls-getcerts.go | 88 +++++++++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 86 insertions(+), 2 deletions(-)

diff --git a/tls-getcerts.go b/tls-getcerts.go
index 49e15a2..7032199 100644
--- a/tls-getcerts.go
+++ b/tls-getcerts.go
@@ -4,17 +4,93 @@ import (
 	"crypto/tls"
 	"crypto/x509"
 	"encoding/pem"
+	"encoding/xml"
 	"fmt"
+	"io"
 	"net"
 	"os"
+	"strings"
 )
 
+type xmppStreamsFeatures struct {
+	XMLName    xml.Name `xml:"http://etherx.jabber.org/streams features"`
+}
+
+type xmppTlsProceed struct {
+	XMLName xml.Name `xml:"urn:ietf:params:xml:ns:xmpp-tls proceed"`
+}
+
+func tlsDial(snet, saddr string) (*tls.Conn, error) {
+	switch snet {
+	case "tcp":
+		conn, err := tls.Dial(snet, saddr, &tls.Config{InsecureSkipVerify: true})
+		if err != nil {
+			return nil, err
+		}
+		return conn, nil
+	case "xmpp":
+		host, _, err := net.SplitHostPort(saddr)
+		connTCP, err := net.Dial("tcp", saddr)
+		if err != nil {
+			return nil, err
+		}
+
+		decoder := xml.NewDecoder(connTCP)
+
+		// send <stream> start
+		_, err = fmt.Fprintf(connTCP, "<stream:stream xmlns='jabber:client' xmlns:stream='http://etherx.jabber.org/streams' to='%s' version='1.0'>", host)
+		if err != nil {
+			return nil, err
+		}
+		// read <stream> start
+		for {
+			t, err := decoder.Token()
+			if err != nil || t == nil {
+				return nil, err
+			}
+			if se, ok := t.(xml.StartElement); ok {
+				if se.Name.Local != "stream" {
+					return nil, xml.UnmarshalError(fmt.Sprintf("expected element of type <%s> but have <%s>", "stream", se.Name.Local))
+				}
+				break
+			}
+		}
+		// read <features>
+		var features xmppStreamsFeatures
+		err = decoder.DecodeElement(&features, nil)
+		if err != nil {
+			return nil, err
+		}
+		// send <starttls>
+		_, err = io.WriteString(connTCP, "<starttls xmlns='urn:ietf:params:xml:ns:xmpp-tls'/>")
+		if err != nil {
+			return nil, err
+		}
+		// read <proceed>
+		var proceed xmppTlsProceed
+		err = decoder.DecodeElement(&proceed, nil)
+		if err != nil {
+			return nil, err
+		}
+
+		connTLS := tls.Client(connTCP, &tls.Config{InsecureSkipVerify: true})
+		err = connTLS.Handshake()
+		if err != nil {
+			return nil, err
+		}
+		return connTLS, nil
+	default:
+		return nil, fmt.Errorf("Unknown TLS network: %q", snet)
+	}
+}
+
 func getcert(socket string) (*x509.Certificate, error){
-	host, _, err := net.SplitHostPort(socket)
+	snet, saddr := split(socket)
+	host, _, err := net.SplitHostPort(saddr)
 	if err != nil {
 		return nil, err
 	}
-	conn, err := tls.Dial("tcp", socket, &tls.Config{InsecureSkipVerify: true})
+	conn, err := tlsDial(snet, saddr)
 	if err != nil {
 		return nil, err
 	}
@@ -34,6 +110,14 @@ func getcert(socket string) (*x509.Certificate, error){
 	return cert, err
 }
 
+func split(socket string) (net, addr string) {
+	ary := strings.SplitN(socket, ":", 2)
+	if len(ary) == 1 {
+		return "tcp", ary[0]
+	}
+	return ary[0], ary[1]
+}
+
 func main() {
 	for _, socket := range os.Args[1:] {
 		cert, err := getcert(socket)
-- 
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