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, 11 insertions, 11 deletions

diff --git a/services/auth/basic.go b/services/auth/basic.go
index 839aaa7a4e..5fb80703ab 100644
--- a/services/auth/basic.go
+++ b/services/auth/basic.go
@@ -40,20 +40,20 @@ func (b *Basic) Name() string {
 // "Authorization" header of the request and returns the corresponding user object for that
 // name/token on successful validation.
 // Returns nil if header is empty or validation fails.
-func (b *Basic) Verify(req *http.Request, w http.ResponseWriter, store DataStore, sess SessionStore) *user_model.User {
+func (b *Basic) Verify(req *http.Request, w http.ResponseWriter, store DataStore, sess SessionStore) (*user_model.User, error) {
 	// Basic authentication should only fire on API, Download or on Git or LFSPaths
 	if !middleware.IsAPIPath(req) && !isContainerPath(req) && !isAttachmentDownload(req) && !isGitRawReleaseOrLFSPath(req) {
-		return nil
+		return nil, nil
 	}
 
 	baHead := req.Header.Get("Authorization")
 	if len(baHead) == 0 {
-		return nil
+		return nil, nil
 	}
 
 	auths := strings.SplitN(baHead, " ", 2)
 	if len(auths) != 2 || (strings.ToLower(auths[0]) != "basic") {
-		return nil
+		return nil, nil
 	}
 
 	uname, passwd, _ := base.BasicAuthDecode(auths[1])
@@ -77,11 +77,11 @@ func (b *Basic) Verify(req *http.Request, w http.ResponseWriter, store DataStore
 		u, err := user_model.GetUserByID(req.Context(), uid)
 		if err != nil {
 			log.Error("GetUserByID:  %v", err)
-			return nil
+			return nil, err
 		}
 
 		store.GetData()["IsApiToken"] = true
-		return u
+		return u, nil
 	}
 
 	token, err := auth_model.GetAccessTokenBySHA(authToken)
@@ -90,7 +90,7 @@ func (b *Basic) Verify(req *http.Request, w http.ResponseWriter, store DataStore
 		u, err := user_model.GetUserByID(req.Context(), token.UID)
 		if err != nil {
 			log.Error("GetUserByID:  %v", err)
-			return nil
+			return nil, err
 		}
 
 		token.UpdatedUnix = timeutil.TimeStampNow()
@@ -99,13 +99,13 @@ func (b *Basic) Verify(req *http.Request, w http.ResponseWriter, store DataStore
 		}
 
 		store.GetData()["IsApiToken"] = true
-		return u
+		return u, nil
 	} else if !auth_model.IsErrAccessTokenNotExist(err) && !auth_model.IsErrAccessTokenEmpty(err) {
 		log.Error("GetAccessTokenBySha: %v", err)
 	}
 
 	if !setting.Service.EnableBasicAuth {
-		return nil
+		return nil, nil
 	}
 
 	log.Trace("Basic Authorization: Attempting SignIn for %s", uname)
@@ -114,7 +114,7 @@ func (b *Basic) Verify(req *http.Request, w http.ResponseWriter, store DataStore
 		if !user_model.IsErrUserNotExist(err) {
 			log.Error("UserSignIn: %v", err)
 		}
-		return nil
+		return nil, err
 	}
 
 	if skipper, ok := source.Cfg.(LocalTwoFASkipper); ok && skipper.IsSkipLocalTwoFA() {
@@ -123,5 +123,5 @@ func (b *Basic) Verify(req *http.Request, w http.ResponseWriter, store DataStore
 
 	log.Trace("Basic Authorization: Logged in user %-v", u)
 
-	return u
+	return u, nil
 }