slight read refactor (seems to fix flaky issues?)

Signed-off-by: Jens Langhammer <jens@goauthentik.io>

internal/outpost/radius/eap/handler.go

@@ -33,7 +33,7 @@ func (p *Packet) Handle(stm StateManager, w radius.ResponseWriter, r *radius.Pac
 
 	rres := r.Response(radius.CodeAccessChallenge)
 	if p, ok := res.Payload.(protocol.EmptyPayload); ok {
-		// This is a bit hacky here
+		// TODO: This is a bit hacky here
 		res.code = CodeSuccess
 		res.id -= 1
 		rres = p.ModifyPacket(rres)

internal/outpost/radius/eap/tls/buff_conn.go

@@ -74,22 +74,26 @@ func (conn BuffConn) NeedsMoreData() bool {
 func (conn *BuffConn) Read(p []byte) (int, error) {
 	d, err := retry.DoWithData(
 		func() (int, error) {
-			n, err := conn.reader.Read(p)
+			if conn.reader.Len() == 0 {
-			if n == 0 {
 				log.Debugf("TLS(buffcon): Attempted read %d from empty buffer, stalling...", len(p))
 				return 0, errStall
 			}
-			if conn.expectedWriterByteCount > 0 && conn.writtenByteCount < int(conn.expectedWriterByteCount) {
+			if conn.expectedWriterByteCount > 0 {
-				log.Debugf("TLS(buffcon): Attempted read %d while waiting for bytes %d, stalling...", len(p), conn.expectedWriterByteCount-conn.reader.Len())
+				// If we're waiting for more data, we need to stall
-				return 0, errStall
+				if conn.writtenByteCount < int(conn.expectedWriterByteCount) {
-			}
+					log.Debugf("TLS(buffcon): Attempted read %d while waiting for bytes %d, stalling...", len(p), conn.expectedWriterByteCount-conn.reader.Len())
-			if conn.expectedWriterByteCount > 0 && conn.writtenByteCount == int(conn.expectedWriterByteCount) {
+					return 0, errStall
-				conn.expectedWriterByteCount = 0
+				}
+				// If we have all the data, reset how much we're expecting to still get
+				if conn.writtenByteCount == int(conn.expectedWriterByteCount) {
+					conn.expectedWriterByteCount = 0
+				}
 			}
 			if conn.reader.Len() == 0 {
 				conn.writtenByteCount = 0
 			}
-			log.Debugf("TLS(buffcon): Read: %d from %d", len(p), n)
+			n, err := conn.reader.Read(p)
+			log.Debugf("TLS(buffcon): Read: %d into %d (total %d)", n, len(p), conn.reader.Len())
 			return n, err
 		},
 		conn.retryOptions...,

internal/outpost/radius/eap/tls/payload.go

@@ -89,33 +89,7 @@ func (p *Payload) Handle(stt any) (protocol.Payload, *State) {
 	}
 
 	if st.TLS == nil {
-		log.Debug("TLS: no TLS connection in state yet, starting connection")
+		st = p.tlsInit(st)
-		st.Context, st.ContextCancel = context.WithTimeout(context.Background(), staleConnectionTimeout*time.Second)
-		st.Conn = NewBuffConn(p.Data, st.Context)
-		st.TLS = tls.Server(st.Conn, &tls.Config{
-			GetConfigForClient: func(ch *tls.ClientHelloInfo) (*tls.Config, error) {
-				log.Debugf("TLS: ClientHello: %+v\n", ch)
-				st.ClientHello = ch
-				return nil, nil
-			},
-			ClientAuth:   tls.RequireAnyClientCert,
-			Certificates: certs,
-			CipherSuites: []uint16{
-				tls.TLS_RSA_WITH_3DES_EDE_CBC_SHA,
-				tls.TLS_RSA_WITH_RC4_128_SHA,
-				tls.TLS_RSA_WITH_AES_128_CBC_SHA,
-				// tls.TLS_RSA_WITH_RC4_128_MD5,
-			},
-		})
-		go func() {
-			err := st.TLS.HandshakeContext(st.Context)
-			if err != nil {
-				log.WithError(err).Debug("TLS: Handshake error")
-				return
-			}
-			log.Debug("TLS: handshake done")
-			p.handshakeFinished(st)
-		}()
 	} else if len(p.Data) > 0 {
 		log.Debug("TLS: Updating buffer with new TLS data from packet")
 		if p.Flags&FlagLengthIncluded != 0 && st.Conn.expectedWriterByteCount == 0 {
@@ -158,7 +132,33 @@ func (p *Payload) Handle(stt any) (protocol.Payload, *State) {
 	return p.startChunkedTransfer(st.Conn.OutboundData(), st)
 }
 
-func (p *Payload) handshakeFinished(st *State) {
+func (p *Payload) tlsInit(st *State) *State {
+	log.Debug("TLS: no TLS connection in state yet, starting connection")
+	st.Context, st.ContextCancel = context.WithTimeout(context.Background(), staleConnectionTimeout*time.Second)
+	st.Conn = NewBuffConn(p.Data, st.Context)
+	st.TLS = tls.Server(st.Conn, &tls.Config{
+		GetConfigForClient: func(ch *tls.ClientHelloInfo) (*tls.Config, error) {
+			log.Debugf("TLS: ClientHello: %+v\n", ch)
+			st.ClientHello = ch
+			return nil, nil
+		},
+		ClientAuth:   tls.RequireAnyClientCert,
+		Certificates: certs,
+	})
+	go func() {
+		err := st.TLS.HandshakeContext(st.Context)
+		if err != nil {
+			log.WithError(err).Debug("TLS: Handshake error")
+			// TODO: Send a NAK to the client
+			return
+		}
+		log.Debug("TLS: handshake done")
+		p.tlsHandshakeFinished(st)
+	}()
+	return st
+}
+
+func (p *Payload) tlsHandshakeFinished(st *State) {
 	cs := st.TLS.ConnectionState()
 	label := "client EAP encryption"
 	var context []byte