Clean up and fix StartTLS feature discovery

Required field was never set to true

auth.go

@@ -50,11 +50,6 @@ func authPlain(socket io.ReadWriter, decoder *xml.Decoder, user string, password
 	return err
 }
 
-type saslMechanisms struct {
-	XMLName   xml.Name `xml:"urn:ietf:params:xml:ns:xmpp-sasl mechanisms"`
-	Mechanism []string `xml:"mechanism"`
-}
-
 // ============================================================================
 // SASLSuccess
 

check_cert.go

@@ -76,8 +76,7 @@ func (c *ServerCheck) Check() error {
 		return errors.New("expected packet received while expecting features, got " + p.Name())
 	}
 
-	startTLSFeature := f.StartTLS.XMLName.Space + " " + f.StartTLS.XMLName.Local
-	if startTLSFeature == nsTLS+" starttls" {
+	if _, ok := f.DoesStartTLS(); ok {
 		fmt.Fprintf(tcpconn, "<starttls xmlns='urn:ietf:params:xml:ns:xmpp-tls'/>")
 
 		var k tlsProceed

client_test.go

@@ -60,6 +60,30 @@ func TestClient_NoInsecure(t *testing.T) {
 	mock.Stop()
 }
 
+// Check that the client is properly tracking features, as session negotiation progresses.
+func TestClient_FeaturesTracking(t *testing.T) {
+	// Setup Mock server
+	mock := ServerMock{}
+	mock.Start(t, testXMPPAddress, handlerAbortTLS)
+
+	// Test / Check result
+	config := Config{Address: testXMPPAddress, Jid: "test@localhost", Password: "test"}
+
+	var client *Client
+	var err error
+	if client, err = NewClient(config); err != nil {
+		t.Errorf("cannot create XMPP client: %s", err)
+	}
+
+	if err = client.Connect(); err == nil {
+		// When insecure is not allowed:
+		t.Errorf("should fail as insecure connection is not allowed and server does not support TLS")
+	}
+
+	mock.Stop()
+
+}
+
 //=============================================================================
 // Basic XMPP Server Mock Handlers.
 

session.go

@@ -109,7 +109,7 @@ func (s *Session) startTlsIfSupported(conn net.Conn, domain string) net.Conn {
 		return conn
 	}
 
-	if s.Features.StartTLS.XMLName.Space+" "+s.Features.StartTLS.XMLName.Local == nsTLS+" starttls" {
+	if _, ok := s.Features.DoesStartTLS(); ok {
 		fmt.Fprintf(s.socketProxy, "<starttls xmlns='urn:ietf:params:xml:ns:xmpp-tls'/>")
 
 		var k tlsProceed

starttls.go

@@ -7,12 +7,7 @@ import (
 
 var DefaultTlsConfig tls.Config
 
-// XMPP Packet Parsing
-type tlsStartTLS struct {
-	XMLName  xml.Name `xml:"urn:ietf:params:xml:ns:xmpp-tls starttls"`
-	Required bool
-}
-
+// Used during stream initiation / session establishment
 type tlsProceed struct {
 	XMLName xml.Name `xml:"urn:ietf:params:xml:ns:xmpp-tls proceed"`
 }

stream.go

@@ -6,11 +6,14 @@ import (
 
 // ============================================================================
 // StreamFeatures Packet
+// Reference: https://xmpp.org/registrar/stream-features.html
 
 type StreamFeatures struct {
-	XMLName    xml.Name `xml:"http://etherx.jabber.org/streams features"`
+	XMLName xml.Name `xml:"http://etherx.jabber.org/streams features"`
+	// Server capabilities hash
+	Caps Caps
+	// Stream features
 	StartTLS   tlsStartTLS
-	Caps       Caps
 	Mechanisms saslMechanisms
 	Bind       BindBind
 	Session    sessionSession
@@ -31,6 +34,76 @@ func (streamFeatureDecoder) decode(p *xml.Decoder, se xml.StartElement) (StreamF
 	return packet, err
 }
 
+// Capabilities
+// Reference: https://xmpp.org/extensions/xep-0115.html#stream
+//    "A server MAY include its entity capabilities in a stream feature element so that connecting clients
+//     and peer servers do not need to send service discovery requests each time they connect."
+// This is not a stream feature but a way to let client cache server disco info.
+type Caps struct {
+	XMLName xml.Name `xml:"http://jabber.org/protocol/caps c"`
+	Hash    string   `xml:"hash,attr"`
+	Node    string   `xml:"node,attr"`
+	Ver     string   `xml:"ver,attr"`
+	Ext     string   `xml:"ext,attr,omitempty"`
+}
+
+// ============================================================================
+// Supported Stream Features
+
+// StartTLS feature
+// Reference: RFC 6120 - https://tools.ietf.org/html/rfc6120#section-5.4
+type tlsStartTLS struct {
+	XMLName  xml.Name `xml:"urn:ietf:params:xml:ns:xmpp-tls starttls"`
+	Required bool
+}
+
+// UnmarshalXML implements custom parsing startTLS required flag
+func (stls *tlsStartTLS) UnmarshalXML(d *xml.Decoder, start xml.StartElement) error {
+	stls.XMLName = start.Name
+
+	// Check subelements to extract required field as boolean
+	for {
+		t, err := d.Token()
+		if err != nil {
+			return err
+		}
+
+		switch tt := t.(type) {
+
+		case xml.StartElement:
+			elt := new(Node)
+
+			err = d.DecodeElement(elt, &tt)
+			if err != nil {
+				return err
+			}
+
+			if elt.XMLName.Local == "required" {
+				stls.Required = true
+			}
+
+		case xml.EndElement:
+			if tt == start.End() {
+				return nil
+			}
+		}
+	}
+}
+
+func (sf *StreamFeatures) DoesStartTLS() (feature tlsStartTLS, isSupported bool) {
+	if sf.StartTLS.XMLName.Space+" "+sf.StartTLS.XMLName.Local == nsTLS+" starttls" {
+		return sf.StartTLS, true
+	}
+	return feature, false
+}
+
+// Mechanisms
+// Reference: RFC 6120 - https://tools.ietf.org/html/rfc6120#section-6.4.1
+type saslMechanisms struct {
+	XMLName   xml.Name `xml:"urn:ietf:params:xml:ns:xmpp-sasl mechanisms"`
+	Mechanism []string `xml:"mechanism"`
+}
+
 // ============================================================================
 // StreamError Packet
 
@@ -53,14 +126,3 @@ func (streamErrorDecoder) decode(p *xml.Decoder, se xml.StartElement) (StreamErr
 	err := p.DecodeElement(&packet, &se)
 	return packet, err
 }
-
-// ============================================================================
-// Caps subElement
-
-type Caps struct {
-	XMLName xml.Name `xml:"http://jabber.org/protocol/caps c"`
-	Hash    string   `xml:"hash,attr"`
-	Node    string   `xml:"node,attr"`
-	Ver     string   `xml:"ver,attr"`
-	Ext     string   `xml:"ext,attr,omitempty"`
-}

stream_test.go

@@ -0,0 +1,47 @@
+package xmpp_test
+
+import (
+	"encoding/xml"
+	"testing"
+
+	"gosrc.io/xmpp"
+)
+
+func TestNoStartTLS(t *testing.T) {
+	streamFeatures := `<stream:features xmlns:stream='http://etherx.jabber.org/streams'>
+</stream:features>`
+
+	var parsedSF xmpp.StreamFeatures
+	if err := xml.Unmarshal([]byte(streamFeatures), &parsedSF); err != nil {
+		t.Errorf("Unmarshal(%s) returned error: %v", streamFeatures, err)
+	}
+
+	startTLS, ok := parsedSF.DoesStartTLS()
+	if ok {
+		t.Error("StartTLS feature should not be enabled")
+	}
+	if startTLS.Required {
+		t.Error("StartTLS cannot be required as default")
+	}
+}
+
+func TestStartTLS(t *testing.T) {
+	streamFeatures := `<stream:features xmlns:stream='http://etherx.jabber.org/streams'>
+  <starttls xmlns='urn:ietf:params:xml:ns:xmpp-tls'>
+    <required/>
+  </starttls>
+</stream:features>`
+
+	var parsedSF xmpp.StreamFeatures
+	if err := xml.Unmarshal([]byte(streamFeatures), &parsedSF); err != nil {
+		t.Errorf("Unmarshal(%s) returned error: %v", streamFeatures, err)
+	}
+
+	startTLS, ok := parsedSF.DoesStartTLS()
+	if !ok {
+		t.Error("StartTLS feature should be enabled")
+	}
+	if !startTLS.Required {
+		t.Error("StartTLS feature should be required")
+	}
+}