package verification
import (
"context"
"errors"
"fmt"
"html"
"mime"
"net"
"net/mail"
"net/smtp"
"strconv"
"strings"
"time"
"git.pcux.cn/xuans/Smail/services/logstore"
smailsmtp "git.pcux.cn/xuans/Smail/utils/smtp"
)
type SecurityMode string
const (
MailDeliveryTimeout = 45 * time.Second
SecurityStartTLS SecurityMode = "starttls"
SecurityImplicitTLS SecurityMode = "tls"
SecurityPlain SecurityMode = "plain"
)
var (
ErrInvalidSMTPConfig = errors.New("invalid SMTP configuration")
ErrUnsupportedSMTP = errors.New("unsupported SMTP security mode")
ErrSMTPRelayUnavailable = errors.New("SMTP relay is unavailable")
ErrProjectMailUnavailable = errors.New("project mail delivery is unavailable")
ErrMailDeliveryFailed = errors.New("verification mail delivery failed")
)
type SMTPSettings struct {
Host string
Port int
Username string
Password string
Security SecurityMode
From string
FromDomain string
}
type SMTPDelivery struct {
settings SMTPSettings
send func(SMTPSettings, string, []byte) error
}
func NewSMTPDelivery(settings SMTPSettings) (*SMTPDelivery, error) {
if err := validateSMTPSettings(settings); err != nil {
return nil, err
}
return &SMTPDelivery{settings: settings, send: sendSMTPMessage}, nil
}
// NewSMTPDeliveryContext 将中继投递纳入调用方的总时限。
func NewSMTPDeliveryContext(ctx context.Context, settings SMTPSettings) (*SMTPDelivery, error) {
delivery, err := NewSMTPDelivery(settings)
if err != nil {
return nil, err
}
delivery.send = func(settings SMTPSettings, recipient string, message []byte) error {
return SendSMTPMessageContext(ctx, settings, recipient, message)
}
return delivery, nil
}
func (d *SMTPDelivery) Delivery() Delivery {
return func(challenge Challenge, code string) error {
if d == nil || d.send == nil || challenge.Email == "" || code == "" {
return ErrInvalidChallenge
}
message := buildCodeMessage(d.settings.From, challenge, code)
defer clearBytes(message)
err := d.send(d.settings, challenge.Email, message)
result := "accepted"
details := logstore.MailDetails{Trigger: "系统安全验证邮件", Stage: "SMTP 中继投递", AcceptedCount: 1}
if err != nil {
result = "failure"
details.AcceptedCount = 0
details.Outcome = logstore.MailFailureReason(err)
}
// 只记录发送元数据，不保存外部邮箱、验证码、邮件内容及中继凭据。
logstore.MailResult(0, "outbound", d.settings.From, 1, len(message), result, details)
return err
}
}
// NewLazySMTPDelivery 延迟读取 SMTP 中继配置，避免中继未配置时阻塞本地邮件服务启动。
func NewLazySMTPDelivery(load func() (SMTPSettings, error)) Delivery {
return func(challenge Challenge, code string) error {
if load == nil || challenge.Email == "" || code == "" {
return ErrSMTPRelayUnavailable
}
settings, err := load()
if err != nil {
return fmt.Errorf("load SMTP relay settings: %w", err)
}
delivery, err := NewSMTPDelivery(settings)
if err != nil {
return fmt.Errorf("SMTP relay is unavailable: %w", err)
}
return delivery.Delivery()(challenge, code)
}
}
func IssueWithSMTP(store *Store, request IssueRequest, settings SMTPSettings) (Challenge, error) {
if store == nil {
return Challenge{}, ErrInvalidChallenge
}
delivery, err := NewSMTPDelivery(settings)
if err != nil {
return Challenge{}, err
}
return store.Issue(request, delivery.Delivery())
}
func validateSMTPSettings(settings SMTPSettings) error {
host := strings.TrimSpace(settings.Host)
if !isValidSMTPHost(host) {
return ErrInvalidSMTPConfig
}
from := strings.TrimSpace(settings.From)
parsedFrom, err := mail.ParseAddress(from)
if err != nil || parsedFrom.Address != from || strings.ContainsAny(from, "\r\n") {
return ErrInvalidSMTPConfig
}
if settings.Port <= 0 || settings.Port > 65535 {
return ErrInvalidSMTPConfig
}
switch settings.Security {
case SecurityStartTLS, SecurityImplicitTLS:
case SecurityPlain:
if !isLocalSMTPHost(host) {
return ErrInvalidSMTPConfig
}
default:
return ErrUnsupportedSMTP
}
if settings.Username == "" && settings.Password != "" {
return ErrInvalidSMTPConfig
}
return nil
}
func isLocalSMTPHost(host string) bool {
normalized := strings.TrimSuffix(strings.ToLower(strings.TrimSpace(host)), ".")
if normalized == "localhost" {
return true
}
ip := net.ParseIP(normalized)
return ip != nil && ip.IsLoopback()
}
func isValidSMTPHost(host string) bool {
if host == "" || strings.ContainsAny(host, "@/\\\r\n\t ") {
return false
}
if net.ParseIP(host) != nil {
return true
}
if strings.Contains(host, ":") {
return false
}
if len(host) > 253 || strings.HasPrefix(host, ".") || strings.HasSuffix(host, ".") {
return false
}
for _, label := range strings.Split(host, ".") {
if label == "" || len(label) > 63 || strings.HasPrefix(label, "-") || strings.HasSuffix(label, "-") {
return false
}
for _, r := range label {
if (r < 'a' || r > 'z') && (r < 'A' || r > 'Z') && (r < '0' || r > '9') && r != '-' {
return false
}
}
}
return true
}
func sendSMTPMessage(settings SMTPSettings, recipient string, message []byte) error {
ctx, cancel := context.WithTimeout(context.Background(), MailDeliveryTimeout)
defer cancel()
return SendSMTPMessageContext(ctx, settings, recipient, message)
}
// SendSMTPMessageContext 允许验证码中继与后备投递共享同一总时限。
func SendSMTPMessageContext(ctx context.Context, settings SMTPSettings, recipient string, message []byte) error {
addr := net.JoinHostPort(settings.Host, strconv.Itoa(settings.Port))
var auth smtp.Auth
if settings.Username != "" {
auth = smtp.PlainAuth("", settings.Username, settings.Password, settings.Host)
}
fromDomain := settings.FromDomain
if fromDomain == "" {
parts := strings.SplitN(settings.From, "@", 2)
if len(parts) == 2 {
fromDomain = parts[1]
}
}
switch settings.Security {
case SecurityStartTLS:
return smailsmtp.SendMailContext(ctx, settings.Host, addr, auth, settings.From, fromDomain, []string{recipient}, message)
case SecurityImplicitTLS:
return smailsmtp.SendMailWithTLSContext(ctx, settings.Host, addr, auth, settings.From, fromDomain, []string{recipient}, message)
case SecurityPlain:
return smailsmtp.SendMailUnsafeContext(ctx, settings.Host, addr, auth, settings.From, fromDomain, []string{recipient}, message)
default:
return ErrUnsupportedSMTP
}
}
func buildCodeMessage(from string, challenge Challenge, code string) []byte {
title, text := CodeMessage(challenge.Purpose, code)
boundary := "=_SmailVerification_"
htmlBody := CodeHTML(challenge, code)
return []byte(fmt.Sprintf(
"From: %s\r\nTo: %s\r\nSubject: %s\r\nMIME-Version: 1.0\r\nContent-Type: multipart/alternative; boundary=\"%s\"\r\n\r\n--%s\r\nContent-Type: text/plain; charset=UTF-8\r\nContent-Transfer-Encoding: 8bit\r\n\r\n%s\r\n--%s\r\nContent-Type: text/html; charset=UTF-8\r\nContent-Transfer-Encoding: 8bit\r\n\r\n%s\r\n--%s--\r\n",
from,
challenge.Email,
mime.QEncoding.Encode("UTF-8", title),
boundary,
boundary,
text,
boundary,
htmlBody,
boundary,
))
}
// CodeHTML 返回验证码邮件的 HTML 正文。
func CodeHTML(challenge Challenge, code string) string {
recipientName := challenge.Account
if strings.TrimSpace(recipientName) == "" {
recipientName = challenge.Email
}
return buildCodeHTML(recipientName, code, verificationExpiryMinutes(challenge))
}
func verificationExpiryMinutes(challenge Challenge) int {
if challenge.ExpiresAt.After(challenge.IssuedAt) && !challenge.IssuedAt.IsZero() {
minutes := int((challenge.ExpiresAt.Sub(challenge.IssuedAt) + time.Minute - 1) / time.Minute)
if minutes > 0 {
return minutes
}
}
return int(DefaultTTL / time.Minute)
}
func buildCodeHTML(recipientName, code string, expiresInMinutes int) string {
return fmt.Sprintf(`
%s，您好：
您的验证码是：
%s
验证码将在 %d 分钟后失效。
如果不是您本人操作，请忽略此邮件。
`,
html.EscapeString(recipientName),
html.EscapeString(code),
expiresInMinutes,
)
}
// CodeMessage 返回验证码邮件的统一标题和正文，供中继与项目自身投递复用。
func CodeMessage(purpose Purpose, code string) (string, string) {
title := "Smail 安全验证码"
purposeText := "完成本次安全验证"
switch purpose {
case PurposeLogin:
purposeText = "完成登录二次验证"
case PurposePasswordRecover:
purposeText = "完成密码恢复验证"
case PurposePasswordChange:
purposeText = "完成修改密码安全验证"
case PurposeAdminLocalReset:
purposeText = "完成超级管理员本机密码重置验证"
case PurposeExternalEmailBind:
purposeText = "完成外部邮箱绑定验证"
case PurposeExternalEmailChange:
purposeText = "完成外部邮箱变更验证"
}
text := fmt.Sprintf("您好，您正在%s。验证码：%s\r\n验证码有效期为十分钟，请勿向他人泄露。", purposeText, code)
return title, text
}
func clearBytes(data []byte) {
for i := range data {
data[i] = 0
}
}