Comply with RFC5746 and RFC5246

- Re-implemented renegotiation to comply with RFC5746 and RFC5246
- Updated conn_test.go to comply with 120 column limit

Author: daanpape

conn_test.go

@@ -2231,8 +2231,8 @@ func TestMultipleHelloVerifyRequest(t *testing.T) {
 	cancel()
 }
 
-// Assert that a DTLS Server always responds with RenegotiationInfo if
-// a ClientHello contained that extension or not.
+// Assert that a DTLS Server only responds with RenegotiationInfo if a ClientHello contained that
+// extension according to RFC5746 section 3.6, RFC5246 section 7.4.1.4 and RFC5746 section 4.2.
 func TestRenegotationInfo(t *testing.T) { //nolint:cyclop
 	// Limit runtime in case of deadlocks
 	lim := test.TimeOut(10 * time.Second)
@@ -2245,8 +2245,8 @@ func TestRenegotationInfo(t *testing.T) { //nolint:cyclop
 	resp := make([]byte, 1024)
 
 	for _, testCase := range []struct {
-		Name                  string
-		SendRenegotiationInfo bool
+		Name                    string
+		ExpectRenegotiationInfo bool
 	}{
 		{
 			"Include RenegotiationInfo",
@@ -2281,7 +2281,7 @@ func TestRenegotationInfo(t *testing.T) { //nolint:cyclop
 			time.Sleep(50 * time.Millisecond)
 
 			extensions := []extension.Extension{}
-			if test.SendRenegotiationInfo {
+			if test.ExpectRenegotiationInfo {
 				extensions = append(extensions, &extension.RenegotiationInfo{
 					RenegotiatedConnection: 0,
 				})
@@ -2311,14 +2311,16 @@ func TestRenegotationInfo(t *testing.T) { //nolint:cyclop
 			serverHello, ok := record.Content.(*handshake.Handshake).Message.(*handshake.MessageServerHello)
 			assert.True(t, ok)
 
-			gotNegotationInfo := false
+			actualNegotationInfo := false
 			for _, v := range serverHello.Extensions {
 				if _, ok := v.(*extension.RenegotiationInfo); ok {
-					gotNegotationInfo = true
+					actualNegotationInfo = true
 				}
 			}
 
-			assert.True(t, gotNegotationInfo, "Expected RenegotiationInfo extension in ServerHello")
+			assert.True(t, test.ExpectRenegotiationInfo == actualNegotationInfo,
+				"NegotationInfo state in ServerHello is incorrect: expected(%t) actual(%t)",
+				test.ExpectRenegotiationInfo, actualNegotationInfo)
 		})
 	}
 }

flight0handler.go

@@ -81,6 +81,8 @@ func flight0Parse(
 			}
 		case *extension.ServerName:
 			state.serverName = ext.ServerName // remote server name
+		case *extension.RenegotiationInfo:
+			state.remoteSupportsRenegotiation = true
 		case *extension.ALPN:
 			state.peerSupportedProtocols = ext.ProtocolNameList
 		case *extension.ConnectionID:

flight4handler.go

@@ -263,9 +263,8 @@ func flight4Generate(
 	_ *handshakeCache,
 	cfg *handshakeConfig,
 ) ([]*packet, *alert.Alert, error) {
-	extensions := []extension.Extension{&extension.RenegotiationInfo{
-		RenegotiatedConnection: 0,
-	}}
+	extensions := []extension.Extension{}
+
 	if (cfg.extendedMasterSecret == RequestExtendedMasterSecret ||
 		cfg.extendedMasterSecret == RequireExtendedMasterSecret) && state.extendedMasterSecret {
 		extensions = append(extensions, &extension.UseExtendedMasterSecret{
@@ -278,6 +277,11 @@ func flight4Generate(
 			MasterKeyIdentifier: cfg.localSRTPMasterKeyIdentifier,
 		})
 	}
+	if state.remoteSupportsRenegotiation {
+		extensions = append(extensions, &extension.RenegotiationInfo{
+			RenegotiatedConnection: 0,
+		})
+	}
 	if state.cipherSuite.AuthenticationType() == CipherSuiteAuthenticationTypeCertificate {
 		extensions = append(extensions, &extension.SupportedPointFormats{
 			PointFormats: []elliptic.CurvePointFormat{elliptic.CurvePointFormatUncompressed},

state.go

@@ -26,6 +26,8 @@ type State struct {
 	cipherSuite               CipherSuite // nil if a cipherSuite hasn't been chosen
 	CipherSuiteID             CipherSuiteID
 
+	remoteSupportsRenegotiation bool // True when Client Hello contained renegotiation extension
+
 	srtpProtectionProfile         atomic.Value // Negotiated SRTPProtectionProfile
 	remoteSRTPMasterKeyIdentifier []byte