// Copyright 2021 The Gitea Authors. All rights reserved.// SPDX-License-Identifier: MIT package smtp import (	"context"	"errors"	"net/smtp"	"net/textproto"	"strings" 	auth_model "forgejo.org/models/auth"	user_model "forgejo.org/models/user"	"forgejo.org/modules/optional"	"forgejo.org/modules/util") // Authenticate queries if the provided login/password is authenticates against the SMTP server// Users will be autoregistered as requiredfunc (source *Source) Authenticate(ctx context.Context, user *user_model.User, userName, password string) (*user_model.User, error) {	// Verify allowed domains.	if len(source.AllowedDomains) > 0 {		idx := strings.Index(userName, "@")		if idx == -1 {			return nil, user_model.ErrUserNotExist{Name: userName}		} else if !util.SliceContainsString(strings.Split(source.AllowedDomains, ","), userName[idx+1:], true) {			return nil, user_model.ErrUserNotExist{Name: userName}		}	} 	var auth smtp.Auth	switch source.Auth {	case PlainAuthentication:		auth = smtp.PlainAuth("", userName, password, source.Host)	case LoginAuthentication:		auth = &loginAuthenticator{userName, password}	case CRAMMD5Authentication:		auth = smtp.CRAMMD5Auth(userName, password)	default:		return nil, errors.New("unsupported SMTP auth type")	} 	if err := Authenticate(auth, source); err != nil {		// Check standard error format first,		// then fallback to worse case.		tperr, ok := err.(*textproto.Error)		if (ok && tperr.Code == 535) ||			strings.Contains(err.Error(), "Username and Password not accepted") {			return nil, user_model.ErrUserNotExist{Name: userName}		}		if (ok && tperr.Code == 534) ||			strings.Contains(err.Error(), "Application-specific password required") {			return nil, user_model.ErrUserNotExist{Name: userName}		}		return nil, err	} 	if user != nil {		return user, nil	} 	username := userName	idx := strings.Index(userName, "@")	if idx > -1 {		username = userName[:idx]	} 	user = &user_model.User{		LowerName:   strings.ToLower(username),		Name:        strings.ToLower(username),		Email:       userName,		Passwd:      password,		LoginType:   auth_model.SMTP,		LoginSource: source.authSource.ID,		LoginName:   userName,	}	overwriteDefault := &user_model.CreateUserOverwriteOptions{		IsActive: optional.Some(true),	} 	if err := user_model.CreateUser(ctx, user, overwriteDefault); err != nil {		return user, err	} 	return user, nil} // IsSkipLocalTwoFA returns if this source should skip local 2fa for password authenticationfunc (source *Source) IsSkipLocalTwoFA() bool {	return source.SkipLocalTwoFA}