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, 7 insertions, 7 deletions

diff --git a/services/auth/httpsign.go b/services/auth/httpsign.go
index e73db4f248..4d52315381 100644
--- a/services/auth/httpsign.go
+++ b/services/auth/httpsign.go
@@ -39,10 +39,10 @@ func (h *HTTPSign) Name() string {
 // Verify extracts and validates HTTPsign from the Signature header of the request and returns
 // the corresponding user object on successful validation.
 // Returns nil if header is empty or validation fails.
-func (h *HTTPSign) Verify(req *http.Request, w http.ResponseWriter, store DataStore, sess SessionStore) *user_model.User {
+func (h *HTTPSign) Verify(req *http.Request, w http.ResponseWriter, store DataStore, sess SessionStore) (*user_model.User, error) {
 	sigHead := req.Header.Get("Signature")
 	if len(sigHead) == 0 {
-		return nil
+		return nil, nil
 	}
 
 	var (
@@ -53,14 +53,14 @@ func (h *HTTPSign) Verify(req *http.Request, w http.ResponseWriter, store DataSt
 	if len(req.Header.Get("X-Ssh-Certificate")) != 0 {
 		// Handle Signature signed by SSH certificates
 		if len(setting.SSH.TrustedUserCAKeys) == 0 {
-			return nil
+			return nil, nil
 		}
 
 		publicKey, err = VerifyCert(req)
 		if err != nil {
 			log.Debug("VerifyCert on request from %s: failed: %v", req.RemoteAddr, err)
 			log.Warn("Failed authentication attempt from %s", req.RemoteAddr)
-			return nil
+			return nil, nil
 		}
 	} else {
 		// Handle Signature signed by Public Key
@@ -68,21 +68,21 @@ func (h *HTTPSign) Verify(req *http.Request, w http.ResponseWriter, store DataSt
 		if err != nil {
 			log.Debug("VerifyPubKey on request from %s: failed: %v", req.RemoteAddr, err)
 			log.Warn("Failed authentication attempt from %s", req.RemoteAddr)
-			return nil
+			return nil, nil
 		}
 	}
 
 	u, err := user_model.GetUserByID(req.Context(), publicKey.OwnerID)
 	if err != nil {
 		log.Error("GetUserByID:  %v", err)
-		return nil
+		return nil, err
 	}
 
 	store.GetData()["IsApiToken"] = true
 
 	log.Trace("HTTP Sign: Logged in user %-v", u)
 
-	return u
+	return u, nil
 }
 
 func VerifyPubKey(r *http.Request) (*asymkey_model.PublicKey, error) {