forgejo/modules/auth/sso/sspi_windows.go
zeripath a2df265476
Add trace logging to SSO methods ()
It is currenly impossible to detect which "SSO" method is responsible for login. This
PR adds some basic trace logging to these methods.

Signed-off-by: Andrew Thornton <art27@cantab.net>
2021-05-09 18:04:53 +02:00

246 lines
7.4 KiB
Go

// Copyright 2019 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 sso
import (
"errors"
"net/http"
"strings"
"code.gitea.io/gitea/models"
"code.gitea.io/gitea/modules/base"
"code.gitea.io/gitea/modules/log"
"code.gitea.io/gitea/modules/setting"
"code.gitea.io/gitea/modules/templates"
"code.gitea.io/gitea/modules/web/middleware"
gouuid "github.com/google/uuid"
"github.com/quasoft/websspi"
"github.com/unrolled/render"
)
const (
tplSignIn base.TplName = "user/auth/signin"
)
var (
// sspiAuth is a global instance of the websspi authentication package,
// which is used to avoid acquiring the server credential handle on
// every request
sspiAuth *websspi.Authenticator
// Ensure the struct implements the interface.
_ SingleSignOn = &SSPI{}
)
// SSPI implements the SingleSignOn interface and authenticates requests
// via the built-in SSPI module in Windows for SPNEGO authentication.
// On successful authentication returns a valid user object.
// Returns nil if authentication fails.
type SSPI struct {
rnd *render.Render
}
// Init creates a new global websspi.Authenticator object
func (s *SSPI) Init() error {
config := websspi.NewConfig()
var err error
sspiAuth, err = websspi.New(config)
if err != nil {
return err
}
s.rnd = render.New(render.Options{
Extensions: []string{".tmpl"},
Directory: "templates",
Funcs: templates.NewFuncMap(),
Asset: templates.GetAsset,
AssetNames: templates.GetAssetNames,
IsDevelopment: !setting.IsProd(),
})
return nil
}
// Free releases resources used by the global websspi.Authenticator object
func (s *SSPI) Free() error {
return sspiAuth.Free()
}
// IsEnabled checks if there is an active SSPI authentication source
func (s *SSPI) IsEnabled() bool {
return models.IsSSPIEnabled()
}
// VerifyAuthData uses SSPI (Windows implementation of SPNEGO) to authenticate the request.
// If authentication is successful, returs 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) VerifyAuthData(req *http.Request, w http.ResponseWriter, store DataStore, sess SessionStore) *models.User {
if !s.shouldAuthenticate(req) {
return nil
}
cfg, err := s.getConfig()
if err != nil {
log.Error("could not get SSPI config: %v", err)
return nil
}
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
err := s.rnd.HTML(w, 401, string(tplSignIn), templates.BaseVars().Merge(store.GetData()))
if err != nil {
log.Error("%v", err)
}
return nil
}
if outToken != "" {
sspiAuth.AppendAuthenticateHeader(w, outToken)
}
username := sanitizeUsername(userInfo.Username, cfg)
if len(username) == 0 {
return nil
}
log.Info("Authenticated as %s\n", username)
user, err := models.GetUserByName(username)
if err != nil {
if !models.IsErrUserNotExist(err) {
log.Error("GetUserByName: %v", err)
return nil
}
if !cfg.AutoCreateUsers {
log.Error("User '%s' not found", username)
return nil
}
user, err = s.newUser(username, cfg)
if err != nil {
log.Error("CreateUser: %v", err)
return nil
}
}
// 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
}
// getConfig retrieves the SSPI configuration from login sources
func (s *SSPI) getConfig() (*models.SSPIConfig, error) {
sources, err := models.ActiveLoginSources(models.LoginSSPI)
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].SSPI(), 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.IsInternalPath(req) {
shouldAuth = false
} else if middleware.IsAPIPath(req) || isAttachmentDownload(req) {
shouldAuth = true
}
return
}
// 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(username string, cfg *models.SSPIConfig) (*models.User, error) {
email := gouuid.New().String() + "@localhost.localdomain"
user := &models.User{
Name: username,
Email: email,
KeepEmailPrivate: true,
Passwd: gouuid.New().String(),
IsActive: cfg.AutoActivateUsers,
Language: cfg.DefaultLanguage,
UseCustomAvatar: true,
Avatar: models.DefaultAvatarLink(),
EmailNotificationsPreference: models.EmailNotificationsDisabled,
}
if err := models.CreateUser(user); 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 *models.SSPIConfig) 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 *models.SSPIConfig) 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
}
// init registers the SSPI auth method as the last method in the list.
// 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.
func init() {
Register(&SSPI{})
}