Don't add the shared folder to your drive is there is an access list

www/common/outer/async-store.js

@@ -2083,6 +2083,9 @@ define([
         Store.addSharedFolder = function (clientId, data, cb) {
             var s = getStore(data.teamId);
             s.manager.addSharedFolder(data, function (id) {
+                if (id && typeof(id) == "object" && id.error) {
+                    return void cb(id);
+                }
                 var send = data.teamId ? s.sendEvent : sendDriveEvent;
                 send('DRIVE_CHANGE', {
                     path: ['drive', UserObject.FILES_DATA]

www/common/proxy-manager.js

@@ -214,7 +214,7 @@ define([
         if (!Env.folders[id]) { return {}; }
         var obj = Env.folders[id].proxy.metadata || {};
         for (var k in Env.user.proxy[UserObject.SHARED_FOLDERS][id] || {}) {
-            var data = JSON.parse(JSON.stringify(Env.user.proxy[UserObject.SHARED_FOLDERS][id][k]));
+            var data = JSON.parse(JSON.stringify(Env.user.proxy[UserObject.SHARED_FOLDERS][id][k] || {}));
             if (k === "href" && data.indexOf('#') === -1) {
                 try {
                     data = Env.user.userObject.cryptor.decrypt(data);
@@ -503,6 +503,17 @@ define([
             };
             if (data.password) { folderData.password = data.password; }
             if (data.owned) { folderData.owners = [Env.edPublic]; }
+        }).nThen(function (waitFor) {
+            Env.Store.getPadMetadata(null, {
+                channel: folderData.channel
+            }, waitFor(function (obj) {
+                if (obj && (obj.error || obj.rejected)) {
+                    waitFor.abort();
+                    return void cb({
+                        error: obj.error || 'ERESTRICTED'
+                    });
+                }
+            }));
         }).nThen(function (waitFor) {
             Env.pinPads([folderData.channel], waitFor());
         }).nThen(function (waitFor) {

www/common/sframe-common-outer.js

@@ -363,7 +363,7 @@ define([
             }
         }).nThen(function (waitFor) {
             if (cfg.afterSecrets) {
-                cfg.afterSecrets(Cryptpad, Utils, secret, waitFor());
+                cfg.afterSecrets(Cryptpad, Utils, secret, waitFor(), sframeChan);
             }
         }).nThen(function (waitFor) {
             // Check if the pad exists on server

www/common/sframe-common.js

@@ -671,6 +671,10 @@ define([
                 UIElements.displayPasswordPrompt(funcs, cfg);
             });
 
+            ctx.sframeChan.on("EV_RESTRICTED_ERROR", function () {
+                UI.errorLoadingScreen(Messages.restrictedError);
+            });
+
             ctx.sframeChan.on("EV_PAD_PASSWORD_ERROR", function () {
                 UI.errorLoadingScreen(Messages.password_error_seed);
             });

www/drive/main.js

@@ -45,11 +45,16 @@ define([
         };
         window.addEventListener('message', onMsg);
     }).nThen(function (/*waitFor*/) {
-        var afterSecrets = function (Cryptpad, Utils, secret, cb) {
+        var afterSecrets = function (Cryptpad, Utils, secret, cb, sframeChan) {
             var _hash = hash.slice(1);
             if (_hash && Utils.LocalStore.isLoggedIn()) {
                 // Add a shared folder!
                 Cryptpad.addSharedFolder(null, secret, function (id) {
+                    if (id && typeof(id) === "object" && id.error) {
+                        sframeChan.event("EV_RESTRICTED_ERROR");
+                        return;
+                    }
+
                     window.CryptPad_newSharedFolder = id;
 
                     // Clear the hash now that the secrets have been generated