refactor auth interface to return error when verify failure (#22119)

This PR changed the Auth interface signature from 
`Verify(http *http.Request, w http.ResponseWriter, store DataStore, sess
SessionStore) *user_model.User`
to 
`Verify(http *http.Request, w http.ResponseWriter, store DataStore, sess
SessionStore) (*user_model.User, error)`.

There is a new return argument `error` which means the verification
condition matched but verify process failed, we should stop the auth
process.

Before this PR, when return a `nil` user, we don't know the reason why
it returned `nil`. If the match condition is not satisfied or it
verified failure? For these two different results, we should have
different handler. If the match condition is not satisfied, we should
try next auth method and if there is no more auth method, it's an
anonymous user. If the condition matched but verify failed, the auth
process should be stop and return immediately.

This will fix #20563

Co-authored-by: KN4CK3R <admin@oldschoolhack.me>
Co-authored-by: Jason Song <i@wolfogre.com>

1 files changed, 3 insertions, 3 deletions

diff --git a/services/auth/session.go b/services/auth/session.go
index ef2c35d58a..c751135738 100644
--- a/services/auth/session.go
+++ b/services/auth/session.go
@@ -29,12 +29,12 @@ func (s *Session) Name() string {
 // Verify checks if there is a user uid stored in the session and returns the user
 // object for that uid.
 // Returns nil if there is no user uid stored in the session.
-func (s *Session) Verify(req *http.Request, w http.ResponseWriter, store DataStore, sess SessionStore) *user_model.User {
+func (s *Session) Verify(req *http.Request, w http.ResponseWriter, store DataStore, sess SessionStore) (*user_model.User, error) {
 	user := SessionUser(sess)
 	if user != nil {
-		return user
+		return user, nil
 	}
-	return nil
+	return nil, nil
 }
 
 // SessionUser returns the user object corresponding to the "uid" session variable.