107 lines
2.5 KiB
Go
107 lines
2.5 KiB
Go
// Copyright 2021 The Gitea Authors. All rights reserved.
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// SPDX-License-Identifier: MIT
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package smtp
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import (
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"crypto/tls"
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"errors"
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"fmt"
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"net"
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"net/smtp"
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"os"
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"strconv"
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)
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// _________ __________________________
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// / _____/ / \__ ___/\______ \
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// \_____ \ / \ / \| | | ___/
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// / \/ Y \ | | |
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// /_______ /\____|__ /____| |____|
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// \/ \/
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type loginAuthenticator struct {
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username, password string
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}
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func (auth *loginAuthenticator) Start(server *smtp.ServerInfo) (string, []byte, error) {
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return "LOGIN", []byte(auth.username), nil
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}
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func (auth *loginAuthenticator) Next(fromServer []byte, more bool) ([]byte, error) {
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if more {
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switch string(fromServer) {
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case "Username:":
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return []byte(auth.username), nil
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case "Password:":
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return []byte(auth.password), nil
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}
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}
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return nil, nil
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}
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// SMTP authentication type names.
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const (
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PlainAuthentication = "PLAIN"
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LoginAuthentication = "LOGIN"
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CRAMMD5Authentication = "CRAM-MD5"
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)
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// Authenticators contains available SMTP authentication type names.
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var Authenticators = []string{PlainAuthentication, LoginAuthentication, CRAMMD5Authentication}
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// ErrUnsupportedLoginType login source is unknown error
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var ErrUnsupportedLoginType = errors.New("Login source is unknown")
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// Authenticate performs an SMTP authentication.
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func Authenticate(a smtp.Auth, source *Source) error {
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tlsConfig := &tls.Config{
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InsecureSkipVerify: source.SkipVerify,
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ServerName: source.Host,
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}
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conn, err := net.Dial("tcp", net.JoinHostPort(source.Host, strconv.Itoa(source.Port)))
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if err != nil {
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return err
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}
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defer conn.Close()
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if source.UseTLS() {
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conn = tls.Client(conn, tlsConfig)
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}
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client, err := smtp.NewClient(conn, source.Host)
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if err != nil {
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return fmt.Errorf("failed to create NewClient: %w", err)
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}
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defer client.Close()
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if !source.DisableHelo {
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hostname := source.HeloHostname
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if len(hostname) == 0 {
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hostname, err = os.Hostname()
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if err != nil {
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return fmt.Errorf("failed to find Hostname: %w", err)
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}
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}
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if err = client.Hello(hostname); err != nil {
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return fmt.Errorf("failed to send Helo: %w", err)
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}
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}
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// If not using SMTPS, always use STARTTLS if available
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hasStartTLS, _ := client.Extension("STARTTLS")
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if !source.UseTLS() && hasStartTLS {
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if err = client.StartTLS(tlsConfig); err != nil {
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return fmt.Errorf("failed to start StartTLS: %w", err)
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}
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}
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if ok, _ := client.Extension("AUTH"); ok {
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return client.Auth(a)
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}
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return ErrUnsupportedLoginType
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}
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