fix: support multiple validateAdminReq actions (#15372)

handle multiple validateAdminReq actions and remove duplicate error responses.

cmd/admin-handler-utils.go

@@ -30,6 +30,10 @@ import (
 	iampolicy "github.com/minio/pkg/iam/policy"
 )
 
+// validateAdminReq will validate request against and return whether it is allowed.
+// If any of the supplied actions are allowed it will be successful.
+// If nil ObjectLayer is returned, the operation is not permitted.
+// When nil ObjectLayer has been returned an error has always been sent to w.
 func validateAdminReq(ctx context.Context, w http.ResponseWriter, r *http.Request, actions ...iampolicy.AdminAction) (ObjectLayer, auth.Credentials) {
 	// Get current object layer instance.
 	objectAPI := newObjectLayerFn()
@@ -41,11 +45,16 @@ func validateAdminReq(ctx context.Context, w http.ResponseWriter, r *http.Reques
 	for _, action := range actions {
 		// Validate request signature.
 		cred, adminAPIErr := checkAdminRequestAuth(ctx, r, action, "")
-		if adminAPIErr != ErrNone {
+		switch adminAPIErr {
+		case ErrNone:
+			return objectAPI, cred
+		case ErrAccessDenied:
+			// Try another
+			continue
+		default:
 			writeErrorResponseJSON(ctx, w, errorCodes.ToAPIErr(adminAPIErr), r.URL)
 			return nil, cred
 		}
-		return objectAPI, cred
 	}
 	writeErrorResponseJSON(ctx, w, errorCodes.ToAPIErr(ErrAccessDenied), r.URL)
 	return nil, auth.Credentials{}