Revert "Add support for AUTH, closes #62" (#206)

This reverts commit 261bbef426.  It was merged to directly master by mistake, and should have gone through the normal release process.

pkg/server/smtp/handler.go

@@ -29,25 +29,12 @@ const (
 	GREET State = iota
 	// READY State: Got HELO, waiting for MAIL
 	READY
-	// LOGIN State: Got AUTH LOGIN command, expecting Username
-	LOGIN
-	// PASSWORD State: Got Username, expecting password
-	PASSWORD
 	// MAIL State: Got MAIL, accepting RCPTs
 	MAIL
 	// DATA State: Got DATA, waiting for "."
 	DATA
 	// QUIT State: Client requested end of session
 	QUIT
-
-	// Messages sent to user during LOGIN auth procedure
-	// Can vary, but values are taken directly from spec
-	// https://tools.ietf.org/html/draft-murchison-sasl-login-00
-
-	//usernameChallenge sent when inviting user to provide username. Is base64 encoded string `User Name`
-	usernameChallenge = "VXNlciBOYW1lAA=="
-	//passwordChallenge sent when inviting user to provide password. Is base64 encoded string `Password`
-	passwordChallenge = "UGFzc3dvcmQA"
 )
 
 // fromRegex captures the from address and optional BODY=8BITMIME clause.  Matches FROM, while
@@ -89,7 +76,6 @@ var commands = map[string]bool{
 	"QUIT":     true,
 	"TURN":     true,
 	"STARTTLS": true,
-	"AUTH":     true,
 }
 
 // Session holds the state of an SMTP session
@@ -167,16 +153,6 @@ func (s *Server) startSession(id int, conn net.Conn) {
 		}
 		line, err := ssn.readLine()
 		if err == nil {
-			//Handle LOGIN/PASSWORD states here, because they don't expect a command
-			switch ssn.state {
-			case LOGIN:
-				ssn.loginHandler(line)
-				continue
-			case PASSWORD:
-				ssn.passwordHandler(line)
-				continue
-			}
-
 			if cmd, arg, ok := ssn.parseCmd(line); ok {
 				// Check against valid SMTP commands
 				if cmd == "" {
@@ -284,7 +260,6 @@ func (s *Session) greetHandler(cmd string, arg string) {
 		// features before SIZE per RFC
 		s.send("250-" + readyBanner)
 		s.send("250-8BITMIME")
-		s.send("250-AUTH PLAIN LOGIN")
 		if s.Server.config.TLSEnabled && s.Server.tlsConfig != nil && s.tlsState == nil {
 			s.send("250-STARTTLS")
 		}
@@ -306,28 +281,7 @@ func parseHelloArgument(arg string) (string, error) {
 	return domain, nil
 }
 
-func (s *Session) loginHandler(line string) {
-	if len(line) == 0 {
-		s.send("500 invalid Username")
-		s.enterState(READY)
-		return
-	}
-	s.send(fmt.Sprintf("334 %v", passwordChallenge))
-	s.enterState(PASSWORD)
-}
-
-func (s *Session) passwordHandler(line string) {
-	if len(line) == 0 {
-		s.send("500 invalid Password")
-		s.enterState(READY)
-		return
-	}
-	s.send("235 Authentication successful")
-	s.enterState(READY)
-}
-
 // READY state -> waiting for MAIL
-// AUTH can change
 func (s *Session) readyHandler(cmd string, arg string) {
 	if cmd == "STARTTLS" {
 		if !s.Server.config.TLSEnabled {
@@ -351,33 +305,6 @@ func (s *Session) readyHandler(cmd string, arg string) {
 		s.tlsState = new(tls.ConnectionState)
 		*s.tlsState = tlsConn.ConnectionState()
 		s.enterState(GREET)
-	} else if cmd == "AUTH" {
-		args := strings.SplitN(arg, " ", 3)
-		authMethod := args[0]
-		switch authMethod {
-		case "PLAIN":
-			{
-				if len(args) != 2 {
-					s.send("500 Bad auth arguments")
-					s.logger.Warn().Msgf("Bad auth attempt: %q", arg)
-					return
-				}
-				s.logger.Info().Msgf("Accepting credentials: %q", args[1])
-				s.send("235 2.7.0 Authentication successful")
-				return
-			}
-		case "LOGIN":
-			{
-				s.send(fmt.Sprintf("334 %v", usernameChallenge))
-				s.enterState(LOGIN)
-				return
-			}
-		default:
-			{
-				s.send(fmt.Sprintf("500 Unsupported AUTH method: %v", authMethod))
-				return
-			}
-		}
 	} else if cmd == "MAIL" {
 		// Capture group 1: from address.  2: optional params.
 		m := fromRegex.FindStringSubmatch(arg)

pkg/server/smtp/handler_test.go

@@ -108,46 +108,6 @@ func TestEmptyEnvelope(t *testing.T) {
 	}
 }
 
-// Test AUTH
-func TestAuth(t *testing.T) {
-	ds := test.NewStore()
-	server, logbuf, teardown := setupSMTPServer(ds)
-	defer teardown()
-
-	//PLAIN AUTH
-	script := []scriptStep{
-		{"EHLO localhost", 250},
-		{"AUTH PLAIN aW5idWNrZXQ6cGFzc3dvcmQK", 235},
-		{"RSET", 250},
-		{"AUTH GSSAPI aW5idWNrZXQ6cGFzc3dvcmQK", 500},
-		{"RSET", 250},
-		{"AUTH PLAIN", 500},
-		{"RSET", 250},
-		{"AUTH PLAIN aW5idWNrZXQ6cG Fzc3dvcmQK", 500},
-	}
-	if err := playSession(t, server, script); err != nil {
-		t.Error(err)
-	}
-
-	//LOGIN AUTH
-	script = []scriptStep{
-		{"EHLO localhost", 250},
-		{"AUTH LOGIN", 334},
-		{"USERNAME", 334},
-		{"PASSWORD", 235},
-	}
-	if err := playSession(t, server, script); err != nil {
-		t.Error(err)
-	}
-
-	if t.Failed() {
-		// Wait for handler to finish logging
-		time.Sleep(2 * time.Second)
-		// Dump buffered log data if there was a failure
-		_, _ = io.Copy(os.Stderr, logbuf)
-	}
-}
-
 // Test commands in READY state
 func TestReadyState(t *testing.T) {
 	ds := test.NewStore()