fix: correct parentUser lookup for OIDC auto expiration (#14154)

fixes #14026

This is a regression from #13884

cmd/iam-store.go

@@ -1457,7 +1457,20 @@ func (store *IAMStoreSys) GetAllParentUsers() []string {
 	res := set.NewStringSet()
 	for _, cred := range cache.iamUsersMap {
 		if cred.IsServiceAccount() || cred.IsTemp() {
-			res.Add(cred.ParentUser)
+			parentUser := cred.ParentUser
+			if cred.SessionToken != "" {
+				claims, err := getClaimsFromToken(cred.SessionToken)
+				if err != nil {
+					continue
+				}
+				if v, ok := claims[subClaim]; ok {
+					subFromToken, ok := v.(string)
+					if ok {
+						parentUser = subFromToken
+					}
+				}
+			}
+			res.Add(parentUser)
 		}
 	}
 

cmd/iam.go

@@ -1006,11 +1006,7 @@ func (sys *IAMSys) purgeExpiredCredentialsForExternalSSO(ctx context.Context) {
 	parentUsers := sys.store.GetAllParentUsers()
 	var expiredUsers []string
 	for _, parentUser := range parentUsers {
-		userid, err := parseOpenIDParentUser(parentUser)
-		if err == errSkipFile {
-			continue
-		}
-		u, err := globalOpenIDConfig.LookupUser(userid)
+		u, err := globalOpenIDConfig.LookupUser(parentUser)
 		if err != nil {
 			logger.LogIf(GlobalContext, err)
 			continue

cmd/sts-handlers.go

@@ -1,4 +1,4 @@
-// Copyright (c) 2015-2021 MinIO, Inc.
+/// Copyright (c) 2015-2021 MinIO, Inc.
 //
 // This file is part of MinIO Object Storage stack
 //
@@ -80,16 +80,6 @@ const (
 	roleArnClaim = "roleArn"
 )
 
-func parseOpenIDParentUser(parentUser string) (userID string, err error) {
-	if strings.HasPrefix(parentUser, "openid:") {
-		tokens := strings.SplitN(strings.TrimPrefix(parentUser, "openid:"), ":", 2)
-		if len(tokens) == 2 {
-			return tokens[0], nil
-		}
-	}
-	return "", errSkipFile
-}
-
 // stsAPIHandlers implements and provides http handlers for AWS STS API.
 type stsAPIHandlers struct{}