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// Copyright 2019 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT
package auth
import (
"context"
"errors"
"net/http"
"strings"
"sync"
"code.gitea.io/gitea/models/auth"
"code.gitea.io/gitea/models/avatars"
user_model "code.gitea.io/gitea/models/user"
"code.gitea.io/gitea/modules/base"
gitea_context "code.gitea.io/gitea/modules/context"
"code.gitea.io/gitea/modules/log"
"code.gitea.io/gitea/modules/setting"
"code.gitea.io/gitea/modules/util"
"code.gitea.io/gitea/modules/web/middleware"
"code.gitea.io/gitea/services/auth/source/sspi"
gouuid "github.com/google/uuid"
)
const (
tplSignIn base.TplName = "user/auth/signin"
)
type SSPIAuth interface {
AppendAuthenticateHeader(w http.ResponseWriter, data string)
Authenticate(r *http.Request, w http.ResponseWriter) (userInfo *SSPIUserInfo, outToken string, err error)
}
var (
sspiAuth SSPIAuth // a global instance of the websspi authenticator to avoid acquiring the server credential handle on every request
sspiAuthOnce sync.Once
sspiAuthErrInit error
// Ensure the struct implements the interface.
_ Method = &SSPI{}
)
// SSPI implements the SingleSignOn interface and authenticates requests
// via the built-in SSPI module in Windows for SPNEGO authentication.
// The SSPI plugin is expected to be executed last, as it returns 401 status code if negotiation
// fails (or if negotiation should continue), which would prevent other authentication methods
// to execute at all.
type SSPI struct{}
// Name represents the name of auth method
func (s *SSPI) Name() string {
return "sspi"
}
// Verify uses SSPI (Windows implementation of SPNEGO) to authenticate the request.
// If authentication is successful, returns the corresponding user object.
// If negotiation should continue or authentication fails, immediately returns a 401 HTTP
// response code, as required by the SPNEGO protocol.
func (s *SSPI) Verify(req *http.Request, w http.ResponseWriter, store DataStore, sess SessionStore) (*user_model.User, error) {
sspiAuthOnce.Do(func() { sspiAuthErrInit = sspiAuthInit() })
if sspiAuthErrInit != nil {
return nil, sspiAuthErrInit
}
if !s.shouldAuthenticate(req) {
return nil, nil
}
cfg, err := s.getConfig(req.Context())
if err != nil {
log.Error("could not get SSPI config: %v", err)
return nil, err
}
log.Trace("SSPI Authorization: Attempting to authenticate")
userInfo, outToken, err := sspiAuth.Authenticate(req, w)
if err != nil {
log.Warn("Authentication failed with error: %v\n", err)
sspiAuth.AppendAuthenticateHeader(w, outToken)
// Include the user login page in the 401 response to allow the user
// to login with another authentication method if SSPI authentication
// fails
store.GetData()["Flash"] = map[string]string{
"ErrorMsg": err.Error(),
}
store.GetData()["EnableOpenIDSignIn"] = setting.Service.EnableOpenIDSignIn
store.GetData()["EnableSSPI"] = true
// in this case, the Verify function is called in Gitea's web context
// FIXME: it doesn't look good to render the page here, why not redirect?
gitea_context.GetWebContext(req).HTML(http.StatusUnauthorized, tplSignIn)
return nil, err
}
if outToken != "" {
sspiAuth.AppendAuthenticateHeader(w, outToken)
}
username := sanitizeUsername(userInfo.Username, cfg)
if len(username) == 0 {
return nil, nil
}
log.Info("Authenticated as %s\n", username)
user, err := user_model.GetUserByName(req.Context(), username)
if err != nil {
if !user_model.IsErrUserNotExist(err) {
log.Error("GetUserByName: %v", err)
return nil, err
}
if !cfg.AutoCreateUsers {
log.Error("User '%s' not found", username)
return nil, nil
}
user, err = s.newUser(req.Context(), username, cfg)
if err != nil {
log.Error("CreateUser: %v", err)
return nil, err
}
}
// Make sure requests to API paths and PWA resources do not create a new session
if !middleware.IsAPIPath(req) && !isAttachmentDownload(req) {
handleSignIn(w, req, sess, user)
}
log.Trace("SSPI Authorization: Logged in user %-v", user)
return user, nil
}
// getConfig retrieves the SSPI configuration from login sources
func (s *SSPI) getConfig(ctx context.Context) (*sspi.Source, error) {
sources, err := auth.ActiveSources(ctx, auth.SSPI)
if err != nil {
return nil, err
}
if len(sources) == 0 {
return nil, errors.New("no active login sources of type SSPI found")
}
if len(sources) > 1 {
return nil, errors.New("more than one active login source of type SSPI found")
}
return sources[0].Cfg.(*sspi.Source), nil
}
func (s *SSPI) shouldAuthenticate(req *http.Request) (shouldAuth bool) {
shouldAuth = false
path := strings.TrimSuffix(req.URL.Path, "/")
if path == "/user/login" {
if req.FormValue("user_name") != "" && req.FormValue("password") != "" {
shouldAuth = false
} else if req.FormValue("auth_with_sspi") == "1" {
shouldAuth = true
}
} else if middleware.IsAPIPath(req) || isAttachmentDownload(req) {
shouldAuth = true
}
return shouldAuth
}
// newUser creates a new user object for the purpose of automatic registration
// and populates its name and email with the information present in request headers.
func (s *SSPI) newUser(ctx context.Context, username string, cfg *sspi.Source) (*user_model.User, error) {
email := gouuid.New().String() + "@localhost.localdomain"
user := &user_model.User{
Name: username,
Email: email,
Passwd: gouuid.New().String(),
Language: cfg.DefaultLanguage,
UseCustomAvatar: true,
Avatar: avatars.DefaultAvatarLink(),
}
emailNotificationPreference := user_model.EmailNotificationsDisabled
overwriteDefault := &user_model.CreateUserOverwriteOptions{
IsActive: util.OptionalBoolOf(cfg.AutoActivateUsers),
KeepEmailPrivate: util.OptionalBoolTrue,
EmailNotificationsPreference: &emailNotificationPreference,
}
if err := user_model.CreateUser(ctx, user, overwriteDefault); err != nil {
return nil, err
}
return user, nil
}
// stripDomainNames removes NETBIOS domain name and separator from down-level logon names
// (eg. "DOMAIN\user" becomes "user"), and removes the UPN suffix (domain name) and separator
// from UPNs (eg. "user@domain.local" becomes "user")
func stripDomainNames(username string) string {
if strings.Contains(username, "\\") {
parts := strings.SplitN(username, "\\", 2)
if len(parts) > 1 {
username = parts[1]
}
} else if strings.Contains(username, "@") {
parts := strings.Split(username, "@")
if len(parts) > 1 {
username = parts[0]
}
}
return username
}
func replaceSeparators(username string, cfg *sspi.Source) string {
newSep := cfg.SeparatorReplacement
username = strings.ReplaceAll(username, "\\", newSep)
username = strings.ReplaceAll(username, "/", newSep)
username = strings.ReplaceAll(username, "@", newSep)
return username
}
func sanitizeUsername(username string, cfg *sspi.Source) string {
if len(username) == 0 {
return ""
}
if cfg.StripDomainNames {
username = stripDomainNames(username)
}
// Replace separators even if we have already stripped the domain name part,
// as the username can contain several separators: eg. "MICROSOFT\useremail@live.com"
username = replaceSeparators(username, cfg)
return username
}
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