gitea/modules/auth/sso/sspi_windows.go

238 lines
7.0 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"
"reflect"
"strings"
"code.gitea.io/gitea/models"
"code.gitea.io/gitea/modules/base"
"code.gitea.io/gitea/modules/log"
"code.gitea.io/gitea/modules/setting"
"gitea.com/macaron/macaron"
"gitea.com/macaron/session"
gouuid "github.com/google/uuid"
"github.com/quasoft/websspi"
)
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 {
}
// Init creates a new global websspi.Authenticator object
func (s *SSPI) Init() error {
config := websspi.NewConfig()
var err error
sspiAuth, err = websspi.New(config)
return err
}
// 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(ctx *macaron.Context, sess session.Store) *models.User {
if !s.shouldAuthenticate(ctx) {
return nil
}
cfg, err := s.getConfig()
if err != nil {
log.Error("could not get SSPI config: %v", err)
return nil
}
userInfo, outToken, err := sspiAuth.Authenticate(ctx.Req.Request, ctx.Resp)
if err != nil {
log.Warn("Authentication failed with error: %v\n", err)
sspiAuth.AppendAuthenticateHeader(ctx.Resp, outToken)
// Include the user login page in the 401 response to allow the user
// to login with another authentication method if SSPI authentication
// fails
addFlashErr(ctx, ctx.Tr("auth.sspi_auth_failed"))
ctx.Data["EnableOpenIDSignIn"] = setting.Service.EnableOpenIDSignIn
ctx.Data["EnableSSPI"] = true
ctx.HTML(401, string(tplSignIn))
return nil
}
if outToken != "" {
sspiAuth.AppendAuthenticateHeader(ctx.Resp, 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(ctx, 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 !isAPIPath(ctx) && !isAttachmentDownload(ctx) {
handleSignIn(ctx, sess, 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(ctx *macaron.Context) (shouldAuth bool) {
shouldAuth = false
path := strings.TrimSuffix(ctx.Req.URL.Path, "/")
if path == "/user/login" {
if ctx.Req.FormValue("user_name") != "" && ctx.Req.FormValue("password") != "" {
shouldAuth = false
} else if ctx.Req.FormValue("auth_with_sspi") == "1" {
shouldAuth = true
}
} else if isAPIPath(ctx) || isAttachmentDownload(ctx) {
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(ctx *macaron.Context, 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: base.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
}
// addFlashErr adds an error message to the Flash object mapped to a macaron.Context
func addFlashErr(ctx *macaron.Context, err string) {
fv := ctx.GetVal(reflect.TypeOf(&session.Flash{}))
if !fv.IsValid() {
return
}
flash, ok := fv.Interface().(*session.Flash)
if !ok {
return
}
flash.Error(err)
ctx.Data["Flash"] = flash
}
// 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{})
}