Benson Yan
2f23a66733
* fix: support SMTP STARTTLS mode and NTLM auth Add explicit SMTP STARTTLS configuration for 587-style connections and keep SSL/TLS as the implicit TLS mode. Prefer PLAIN when advertised, keep LOGIN compatibility, and add NTLM as a fallback for Exchange SMTP servers that require it after STARTTLS. * fix: respect explicit SMTP encryption mode * fix: preserve SMTP TLS compatibility
137 lines
3.1 KiB
Go
137 lines
3.1 KiB
Go
package common
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import (
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"crypto/tls"
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"encoding/base64"
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"fmt"
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"net/smtp"
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"slices"
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"strings"
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"time"
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)
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func generateMessageID() (string, error) {
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split := strings.Split(SMTPFrom, "@")
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if len(split) < 2 {
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return "", fmt.Errorf("invalid SMTP account")
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}
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domain := strings.Split(SMTPFrom, "@")[1]
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return fmt.Sprintf("<%d.%s@%s>", time.Now().UnixNano(), GetRandomString(12), domain), nil
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}
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func shouldUseSMTPLoginAuth() bool {
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if SMTPForceAuthLogin {
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return true
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}
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return isOutlookServer(SMTPAccount) || slices.Contains(EmailLoginAuthServerList, SMTPServer)
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}
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func getSMTPAuth() smtp.Auth {
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return AutoSMTPAuth(SMTPAccount, SMTPToken)
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}
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func shouldAuthenticateSMTP() bool {
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return SMTPAccount != "" && SMTPToken != ""
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}
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func smtpTLSConfig() *tls.Config {
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return &tls.Config{
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ServerName: SMTPServer,
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InsecureSkipVerify: SMTPInsecureSkipVerify, // #nosec G402 -- admin-controlled SMTP compatibility option.
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}
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}
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func newSMTPClient(addr string) (*smtp.Client, error) {
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if SMTPSSLEnabled || (SMTPPort == 465 && !SMTPStartTLSEnabled) {
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conn, err := tls.Dial("tcp", addr, smtpTLSConfig())
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if err != nil {
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return nil, err
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}
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client, err := smtp.NewClient(conn, SMTPServer)
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if err != nil {
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_ = conn.Close()
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return nil, err
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}
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return client, nil
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}
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client, err := smtp.Dial(addr)
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if err != nil {
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return nil, err
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}
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if SMTPStartTLSEnabled {
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startTLSSupported, _ := client.Extension("STARTTLS")
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if !startTLSSupported {
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_ = client.Close()
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return nil, fmt.Errorf("SMTP server does not support STARTTLS")
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}
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if err := client.StartTLS(smtpTLSConfig()); err != nil {
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_ = client.Close()
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return nil, err
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}
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}
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return client, nil
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}
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func SendEmail(subject string, receiver string, content string) error {
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if SMTPFrom == "" { // for compatibility
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SMTPFrom = SMTPAccount
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}
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id, err2 := generateMessageID()
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if err2 != nil {
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return err2
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}
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if SMTPServer == "" && SMTPAccount == "" {
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return fmt.Errorf("SMTP 服务器未配置")
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}
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encodedSubject := fmt.Sprintf("=?UTF-8?B?%s?=", base64.StdEncoding.EncodeToString([]byte(subject)))
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mail := []byte(fmt.Sprintf("To: %s\r\n"+
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"From: %s <%s>\r\n"+
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"Subject: %s\r\n"+
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"Date: %s\r\n"+
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"Message-ID: %s\r\n"+ // 添加 Message-ID 头
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"Content-Type: text/html; charset=UTF-8\r\n\r\n%s\r\n",
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receiver, SystemName, SMTPFrom, encodedSubject, time.Now().Format(time.RFC1123Z), id, content))
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auth := getSMTPAuth()
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addr := fmt.Sprintf("%s:%d", SMTPServer, SMTPPort)
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to := strings.Split(receiver, ";")
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var err error
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client, err := newSMTPClient(addr)
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if err != nil {
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return err
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}
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defer client.Close()
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if shouldAuthenticateSMTP() {
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if err = client.Auth(auth); err != nil {
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return err
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}
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}
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if err = client.Mail(SMTPFrom); err != nil {
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return err
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}
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for _, receiver := range to {
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if err = client.Rcpt(receiver); err != nil {
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return err
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}
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}
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w, err := client.Data()
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if err != nil {
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return err
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}
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_, err = w.Write(mail)
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if err != nil {
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return err
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}
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err = w.Close()
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if err != nil {
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return err
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}
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err = client.Quit()
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if err != nil {
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SysError(fmt.Sprintf("failed to send email to %s: %v", receiver, err))
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}
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return err
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}
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