Unify two factor check (#27915) (#27929)

Backport #27915 by @KN4CK3R

Fixes #27819

We have support for two factor logins with the normal web login and with
basic auth. For basic auth the two factor check was implemented at three
different places and you need to know that this check is necessary. This
PR moves the check into the basic auth itself.

Co-authored-by: KN4CK3R <admin@oldschoolhack.me>

services/auth/basic.go

@@ -15,6 +15,7 @@ import (
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/setting"
 	"code.gitea.io/gitea/modules/timeutil"
+	"code.gitea.io/gitea/modules/util"
 	"code.gitea.io/gitea/modules/web/middleware"
 )
 
@@ -131,11 +132,30 @@ func (b *Basic) Verify(req *http.Request, w http.ResponseWriter, store DataStore
 		return nil, err
 	}
 
-	if skipper, ok := source.Cfg.(LocalTwoFASkipper); ok && skipper.IsSkipLocalTwoFA() {
-		store.GetData()["SkipLocalTwoFA"] = true
+	if skipper, ok := source.Cfg.(LocalTwoFASkipper); !ok || !skipper.IsSkipLocalTwoFA() {
+		if err := validateTOTP(req, u); err != nil {
+			return nil, err
+		}
 	}
 
 	log.Trace("Basic Authorization: Logged in user %-v", u)
 
 	return u, nil
 }
+
+func validateTOTP(req *http.Request, u *user_model.User) error {
+	twofa, err := auth_model.GetTwoFactorByUID(req.Context(), u.ID)
+	if err != nil {
+		if auth_model.IsErrTwoFactorNotEnrolled(err) {
+			// No 2FA enrollment for this user
+			return nil
+		}
+		return err
+	}
+	if ok, err := twofa.ValidateTOTP(req.Header.Get("X-Gitea-OTP")); err != nil {
+		return err
+	} else if !ok {
+		return util.NewInvalidArgumentErrorf("invalid provided OTP")
+	}
+	return nil
+}