Avoid crashes on peers if IAMSys is not initialized (#8636)

cmd/peer-rest-server.go

@@ -172,6 +172,11 @@ func (s *peerRESTServer) DeletePolicyHandler(w http.ResponseWriter, r *http.Requ
 		return
 	}
 
+	if globalIAMSys == nil {
+		s.writeErrorResponse(w, errServerNotInitialized)
+		return
+	}
+
 	vars := mux.Vars(r)
 	policyName := vars[peerRESTPolicy]
 	if policyName == "" {
@@ -200,6 +205,11 @@ func (s *peerRESTServer) LoadPolicyHandler(w http.ResponseWriter, r *http.Reques
 		return
 	}
 
+	if globalIAMSys == nil {
+		s.writeErrorResponse(w, errServerNotInitialized)
+		return
+	}
+
 	vars := mux.Vars(r)
 	policyName := vars[peerRESTPolicy]
 	if policyName == "" {
@@ -228,6 +238,11 @@ func (s *peerRESTServer) LoadPolicyMappingHandler(w http.ResponseWriter, r *http
 		return
 	}
 
+	if globalIAMSys == nil {
+		s.writeErrorResponse(w, errServerNotInitialized)
+		return
+	}
+
 	vars := mux.Vars(r)
 	userOrGroup := vars[peerRESTUserOrGroup]
 	if userOrGroup == "" {
@@ -257,6 +272,11 @@ func (s *peerRESTServer) DeleteUserHandler(w http.ResponseWriter, r *http.Reques
 		return
 	}
 
+	if globalIAMSys == nil {
+		s.writeErrorResponse(w, errServerNotInitialized)
+		return
+	}
+
 	vars := mux.Vars(r)
 	accessKey := vars[peerRESTUser]
 	if accessKey == "" {
@@ -285,6 +305,11 @@ func (s *peerRESTServer) LoadUserHandler(w http.ResponseWriter, r *http.Request)
 		return
 	}
 
+	if globalIAMSys == nil {
+		s.writeErrorResponse(w, errServerNotInitialized)
+		return
+	}
+
 	vars := mux.Vars(r)
 	accessKey := vars[peerRESTUser]
 	if accessKey == "" {
@@ -313,6 +338,17 @@ func (s *peerRESTServer) LoadUsersHandler(w http.ResponseWriter, r *http.Request
 		return
 	}
 
+	objAPI := newObjectLayerWithoutSafeModeFn()
+	if objAPI == nil {
+		s.writeErrorResponse(w, errServerNotInitialized)
+		return
+	}
+
+	if globalIAMSys == nil {
+		s.writeErrorResponse(w, errServerNotInitialized)
+		return
+	}
+
 	err := globalIAMSys.Load()
 	if err != nil {
 		s.writeErrorResponse(w, err)
@@ -335,6 +371,11 @@ func (s *peerRESTServer) LoadGroupHandler(w http.ResponseWriter, r *http.Request
 		return
 	}
 
+	if globalIAMSys == nil {
+		s.writeErrorResponse(w, errServerNotInitialized)
+		return
+	}
+
 	vars := mux.Vars(r)
 	group := vars[peerRESTGroup]
 	err := globalIAMSys.LoadGroup(objAPI, group)