1 files changed, 71 insertions, 0 deletions
diff --git a/services/auth/source/smtp/source_authenticate.go b/services/auth/source/smtp/source_authenticate.go
new file mode 100644
index 0000000000..9bab86604b
--- /dev/null
+++ b/services/auth/source/smtp/source_authenticate.go
@@ -0,0 +1,71 @@
+// Copyright 2021 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package smtp
+
+import (
+	"errors"
+	"net/smtp"
+	"net/textproto"
+	"strings"
+
+	"code.gitea.io/gitea/models"
+	"code.gitea.io/gitea/modules/util"
+)
+
+// Authenticate queries if the provided login/password is authenticates against the SMTP server
+// Users will be autoregistered as required
+func (source *Source) Authenticate(user *models.User, login, password string) (*models.User, error) {
+	// Verify allowed domains.
+	if len(source.AllowedDomains) > 0 {
+		idx := strings.Index(login, "@")
+		if idx == -1 {
+			return nil, models.ErrUserNotExist{Name: login}
+		} else if !util.IsStringInSlice(login[idx+1:], strings.Split(source.AllowedDomains, ","), true) {
+			return nil, models.ErrUserNotExist{Name: login}
+		}
+	}
+
+	var auth smtp.Auth
+	if source.Auth == PlainAuthentication {
+		auth = smtp.PlainAuth("", login, password, source.Host)
+	} else if source.Auth == LoginAuthentication {
+		auth = &loginAuthenticator{login, password}
+	} else {
+		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, models.ErrUserNotExist{Name: login}
+		}
+		return nil, err
+	}
+
+	if user != nil {
+		return user, nil
+	}
+
+	username := login
+	idx := strings.Index(login, "@")
+	if idx > -1 {
+		username = login[:idx]
+	}
+
+	user = &models.User{
+		LowerName:   strings.ToLower(username),
+		Name:        strings.ToLower(username),
+		Email:       login,
+		Passwd:      password,
+		LoginType:   models.LoginSMTP,
+		LoginSource: source.loginSource.ID,
+		LoginName:   login,
+		IsActive:    true,
+	}
+	return user, models.CreateUser(user)
+}