Make LDAP be able to skip local 2FA (#16954)

This PR extends #16594 to allow LDAP to be able to be set to skip local 2FA too. The technique used here would be extensible to PAM and SMTP sources.

Signed-off-by: Andrew Thornton <[email protected]>

Author: zeripath

cmd/admin_auth_ldap.go

@@ -89,6 +89,10 @@ var (
 			Name:  "public-ssh-key-attribute",
 			Usage: "The attribute of the user’s LDAP record containing the user’s public ssh key.",
 		},
+		cli.BoolFlag{
+			Name:  "skip-local-2fa",
+			Usage: "Set to true to skip local 2fa for users authenticated by this source",
+		},
 	}
 
 	ldapBindDnCLIFlags = append(commonLdapCLIFlags,
@@ -245,6 +249,10 @@ func parseLdapConfig(c *cli.Context, config *ldap.Source) error {
 	if c.IsSet("allow-deactivate-all") {
 		config.AllowDeactivateAll = c.Bool("allow-deactivate-all")
 	}
+	if c.IsSet("skip-local-2fa") {
+		config.SkipLocalTwoFA = c.Bool("skip-local-2fa")
+	}
+
 	return nil
 }
 

modules/context/api.go

@@ -214,6 +214,10 @@ func (ctx *APIContext) RequireCSRF() {
 
 // CheckForOTP validates OTP
 func (ctx *APIContext) CheckForOTP() {
+	if skip, ok := ctx.Data["SkipLocalTwoFA"]; ok && skip.(bool) {
+		return // Skip 2FA
+	}
+
 	otpHeader := ctx.Req.Header.Get("X-Gitea-OTP")
 	twofa, err := models.GetTwoFactorByUID(ctx.Context.User.ID)
 	if err != nil {

modules/context/auth.go

@@ -151,6 +151,9 @@ func ToggleAPI(options *ToggleOptions) func(ctx *APIContext) {
 				return
 			}
 			if ctx.IsSigned && ctx.IsBasicAuth {
+				if skip, ok := ctx.Data["SkipLocalTwoFA"]; ok && skip.(bool) {
+					return // Skip 2FA
+				}
 				twofa, err := models.GetTwoFactorByUID(ctx.User.ID)
 				if err != nil {
 					if models.IsErrTwoFactorNotEnrolled(err) {

routers/web/admin/auths.go

@@ -145,6 +145,7 @@ func parseLDAPConfig(form forms.AuthenticationForm) *ldap.Source {
 		RestrictedFilter:      form.RestrictedFilter,
 		AllowDeactivateAll:    form.AllowDeactivateAll,
 		Enabled:               true,
+		SkipLocalTwoFA:        form.SkipLocalTwoFA,
 	}
 }
 

routers/web/user/auth.go

@@ -175,7 +175,7 @@ func SignInPost(ctx *context.Context) {
 	}
 
 	form := web.GetForm(ctx).(*forms.SignInForm)
-	u, err := auth.UserSignIn(form.UserName, form.Password)
+	u, source, err := auth.UserSignIn(form.UserName, form.Password)
 	if err != nil {
 		if models.IsErrUserNotExist(err) {
 			ctx.RenderWithErr(ctx.Tr("form.username_password_incorrect"), tplSignIn, &form)
@@ -201,6 +201,15 @@ func SignInPost(ctx *context.Context) {
 		}
 		return
 	}
+
+	// Now handle 2FA:
+
+	// First of all if the source can skip local two fa we're done
+	if skipper, ok := source.Cfg.(auth.LocalTwoFASkipper); ok && skipper.IsSkipLocalTwoFA() {
+		handleSignIn(ctx, u, form.Remember)
+		return
+	}
+
 	// If this user is enrolled in 2FA, we can't sign the user in just yet.
 	// Instead, redirect them to the 2FA authentication page.
 	_, err = models.GetTwoFactorByUID(u.ID)
@@ -905,7 +914,7 @@ func LinkAccountPostSignIn(ctx *context.Context) {
 		return
 	}
 
-	u, err := auth.UserSignIn(signInForm.UserName, signInForm.Password)
+	u, _, err := auth.UserSignIn(signInForm.UserName, signInForm.Password)
 	if err != nil {
 		if models.IsErrUserNotExist(err) {
 			ctx.Data["user_exists"] = true
@@ -924,6 +933,7 @@ func linkAccount(ctx *context.Context, u *models.User, gothUser goth.User, remem
 
 	// If this user is enrolled in 2FA, we can't sign the user in just yet.
 	// Instead, redirect them to the 2FA authentication page.
+	// We deliberately ignore the skip local 2fa setting here because we are linking to a previous user here
 	_, err := models.GetTwoFactorByUID(u.ID)
 	if err != nil {
 		if !models.IsErrTwoFactorNotEnrolled(err) {

routers/web/user/auth_openid.go

@@ -291,7 +291,7 @@ func ConnectOpenIDPost(ctx *context.Context) {
 	ctx.Data["EnableOpenIDSignUp"] = setting.Service.EnableOpenIDSignUp
 	ctx.Data["OpenID"] = oid
 
-	u, err := auth.UserSignIn(form.UserName, form.Password)
+	u, _, err := auth.UserSignIn(form.UserName, form.Password)
 	if err != nil {
 		if models.IsErrUserNotExist(err) {
 			ctx.RenderWithErr(ctx.Tr("form.username_password_incorrect"), tplConnectOID, &form)

routers/web/user/setting/account.go

@@ -229,7 +229,7 @@ func DeleteAccount(ctx *context.Context) {
 	ctx.Data["Title"] = ctx.Tr("settings")
 	ctx.Data["PageIsSettingsAccount"] = true
 
-	if _, err := auth.UserSignIn(ctx.User.Name, ctx.FormString("password")); err != nil {
+	if _, _, err := auth.UserSignIn(ctx.User.Name, ctx.FormString("password")); err != nil {
 		if models.IsErrUserNotExist(err) {
 			loadAccountData(ctx)
 

services/auth/basic.go

@@ -107,14 +107,18 @@ func (b *Basic) Verify(req *http.Request, w http.ResponseWriter, store DataStore
 	}
 
 	log.Trace("Basic Authorization: Attempting SignIn for %s", uname)
-	u, err := UserSignIn(uname, passwd)
+	u, source, err := UserSignIn(uname, passwd)
 	if err != nil {
 		if !models.IsErrUserNotExist(err) {
 			log.Error("UserSignIn: %v", err)
 		}
 		return nil
 	}
 
+	if skipper, ok := source.Cfg.(LocalTwoFASkipper); ok && skipper.IsSkipLocalTwoFA() {
+		store.GetData()["SkipLocalTwoFA"] = true
+	}
+
 	log.Trace("Basic Authorization: Logged in user %-v", u)
 
 	return u

services/auth/interface.go

@@ -54,6 +54,11 @@ type PasswordAuthenticator interface {
 	Authenticate(user *models.User, login, password string) (*models.User, error)
 }
 
+// LocalTwoFASkipper represents a source of authentication that can skip local 2fa
+type LocalTwoFASkipper interface {
+	IsSkipLocalTwoFA() bool
+}
+
 // SynchronizableSource represents a source that can synchronize users
 type SynchronizableSource interface {
 	Sync(ctx context.Context, updateExisting bool) error

services/auth/signin.go

@@ -20,66 +20,66 @@ import (
 )
 
 // UserSignIn validates user name and password.
-func UserSignIn(username, password string) (*models.User, error) {
+func UserSignIn(username, password string) (*models.User, *models.LoginSource, error) {
 	var user *models.User
 	if strings.Contains(username, "@") {
 		user = &models.User{Email: strings.ToLower(strings.TrimSpace(username))}
 		// check same email
 		cnt, err := models.Count(user)
 		if err != nil {
-			return nil, err
+			return nil, nil, err
 		}
 		if cnt > 1 {
-			return nil, models.ErrEmailAlreadyUsed{
+			return nil, nil, models.ErrEmailAlreadyUsed{
 				Email: user.Email,
 			}
 		}
 	} else {
 		trimmedUsername := strings.TrimSpace(username)
 		if len(trimmedUsername) == 0 {
-			return nil, models.ErrUserNotExist{Name: username}
+			return nil, nil, models.ErrUserNotExist{Name: username}
 		}
 
 		user = &models.User{LowerName: strings.ToLower(trimmedUsername)}
 	}
 
 	hasUser, err := models.GetUser(user)
 	if err != nil {
-		return nil, err
+		return nil, nil, err
 	}
 
 	if hasUser {
 		source, err := models.GetLoginSourceByID(user.LoginSource)
 		if err != nil {
-			return nil, err
+			return nil, nil, err
 		}
 
 		if !source.IsActive {
-			return nil, models.ErrLoginSourceNotActived
+			return nil, nil, models.ErrLoginSourceNotActived
 		}
 
 		authenticator, ok := source.Cfg.(PasswordAuthenticator)
 		if !ok {
-			return nil, models.ErrUnsupportedLoginType
+			return nil, nil, models.ErrUnsupportedLoginType
 		}
 
 		user, err := authenticator.Authenticate(user, username, password)
 		if err != nil {
-			return nil, err
+			return nil, nil, err
 		}
 
 		// WARN: DON'T check user.IsActive, that will be checked on reqSign so that
 		// user could be hint to resend confirm email.
 		if user.ProhibitLogin {
-			return nil, models.ErrUserProhibitLogin{UID: user.ID, Name: user.Name}
+			return nil, nil, models.ErrUserProhibitLogin{UID: user.ID, Name: user.Name}
 		}
 
-		return user, nil
+		return user, source, nil
 	}
 
 	sources, err := models.AllActiveLoginSources()
 	if err != nil {
-		return nil, err
+		return nil, nil, err
 	}
 
 	for _, source := range sources {
@@ -97,7 +97,7 @@ func UserSignIn(username, password string) (*models.User, error) {
 
 		if err == nil {
 			if !authUser.ProhibitLogin {
-				return authUser, nil
+				return authUser, source, nil
 			}
 			err = models.ErrUserProhibitLogin{UID: authUser.ID, Name: authUser.Name}
 		}
@@ -109,5 +109,5 @@ func UserSignIn(username, password string) (*models.User, error) {
 		}
 	}
 
-	return nil, models.ErrUserNotExist{Name: username}
+	return nil, nil, models.ErrUserNotExist{Name: username}
 }