fix: protected fields exposed via LiveQuery; this removes protected fields from the client response; this may be a breaking change if your app is currently expecting to receive these protected fields ([GHSA-crrq-vr9j-fxxh](https://github.com/parse-community/parse-server/security/advisories/GHSA-crrq-vr9j-fxxh)) (#8074)

spec/ParseLiveQuery.spec.js

@@ -974,6 +974,52 @@ describe('ParseLiveQuery', function () {
     }
   });
 
+  it('should strip out protected fields', async () => {
+    await reconfigureServer({
+      liveQuery: { classNames: ['Test'] },
+      startLiveQueryServer: true,
+    });
+    const obj1 = new Parse.Object('Test');
+    obj1.set('foo', 'foo');
+    obj1.set('bar', 'bar');
+    obj1.set('qux', 'qux');
+    await obj1.save();
+    const config = Config.get(Parse.applicationId);
+    const schemaController = await config.database.loadSchema();
+    await schemaController.updateClass(
+      'Test',
+      {},
+      {
+        get: { '*': true },
+        find: { '*': true },
+        update: { '*': true },
+        protectedFields: {
+          '*': ['foo'],
+        },
+      }
+    );
+    const object = await obj1.fetch();
+    expect(object.get('foo')).toBe(undefined);
+    expect(object.get('bar')).toBeDefined();
+    expect(object.get('qux')).toBeDefined();
+
+    const subscription = await new Parse.Query('Test').subscribe();
+    await Promise.all([
+      new Promise(resolve => {
+        subscription.on('update', (obj, original) => {
+          expect(obj.get('foo')).toBe(undefined);
+          expect(obj.get('bar')).toBeDefined();
+          expect(obj.get('qux')).toBeDefined();
+          expect(original.get('foo')).toBe(undefined);
+          expect(original.get('bar')).toBeDefined();
+          expect(original.get('qux')).toBeDefined();
+          resolve();
+        });
+      }),
+      obj1.save({ foo: 'abc' }),
+    ]);
+  });
+
   afterEach(async function (done) {
     const client = await Parse.CoreManager.getLiveQueryController().getDefaultLiveQueryClient();
     client.close();

src/Controllers/DatabaseController.js

@@ -123,7 +123,7 @@ const filterSensitiveData = (
   aclGroup: any[],
   auth: any,
   operation: any,
-  schema: SchemaController.SchemaController,
+  schema: SchemaController.SchemaController | any,
   className: string,
   protectedFields: null | Array<any>,
   object: any
@@ -132,7 +132,8 @@ const filterSensitiveData = (
   if (auth && auth.user) userId = auth.user.id;
 
   // replace protectedFields when using pointer-permissions
-  const perms = schema.getClassLevelPermissions(className);
+  const perms =
+    schema && schema.getClassLevelPermissions ? schema.getClassLevelPermissions(className) : {};
   if (perms) {
     const isReadOperation = ['get', 'find'].indexOf(operation) > -1;
 
@@ -1430,14 +1431,17 @@ class DatabaseController {
   }
 
   addProtectedFields(
-    schema: SchemaController.SchemaController,
+    schema: SchemaController.SchemaController | any,
     className: string,
     query: any = {},
     aclGroup: any[] = [],
     auth: any = {},
     queryOptions: FullQueryOptions = {}
   ): null | string[] {
-    const perms = schema.getClassLevelPermissions(className);
+    const perms =
+      schema && schema.getClassLevelPermissions
+        ? schema.getClassLevelPermissions(className)
+        : schema;
     if (!perms) return null;
 
     const protectedFields = perms.protectedFields;
@@ -1741,8 +1745,10 @@ class DatabaseController {
   }
 
   static _validateQuery: any => void;
+  static filterSensitiveData: (boolean, any[], any, any, any, string, any[], any) => void;
 }
 
 module.exports = DatabaseController;
 // Expose validateQuery for tests
 module.exports._validateQuery = validateQuery;
+module.exports.filterSensitiveData = filterSensitiveData;

src/LiveQuery/ParseCloudCodePublisher.js

@@ -33,6 +33,9 @@ class ParseCloudCodePublisher {
     if (request.original) {
       message.originalParseObject = request.original._toFullJSON();
     }
+    if (request.classLevelPermissions) {
+      message.classLevelPermissions = request.classLevelPermissions;
+    }
     this.parsePublisher.publish(type, JSON.stringify(message));
   }
 }

src/LiveQuery/ParseLiveQueryServer.js

@@ -17,9 +17,10 @@ import {
   maybeRunAfterEventTrigger,
 } from '../triggers';
 import { getAuthForSessionToken, Auth } from '../Auth';
-import { getCacheController } from '../Controllers';
+import { getCacheController, getDatabaseController } from '../Controllers';
 import LRU from 'lru-cache';
 import UserRouter from '../Routers/UsersRouter';
+import DatabaseController from '../Controllers/DatabaseController';
 
 class ParseLiveQueryServer {
   clients: Map;
@@ -171,7 +172,7 @@ class ParseLiveQueryServer {
               };
               return maybeRunAfterEventTrigger('afterEvent', className, res);
             })
-            .then(() => {
+            .then(async () => {
               if (!res.sendEvent) {
                 return;
               }
@@ -179,14 +180,14 @@ class ParseLiveQueryServer {
                 deletedParseObject = res.object.toJSON();
                 deletedParseObject.className = className;
               }
-              if (
-                (deletedParseObject.className === '_User' ||
-                  deletedParseObject.className === '_Session') &&
-                !client.hasMasterKey
-              ) {
-                delete deletedParseObject.sessionToken;
-                delete deletedParseObject.authData;
-              }
+              await this._filterSensitiveData(
+                classLevelPermissions,
+                res,
+                client,
+                requestId,
+                op,
+                subscription.query
+              );
               client.pushDelete(requestId, deletedParseObject);
             })
             .catch(error => {
@@ -310,7 +311,7 @@ class ParseLiveQueryServer {
               return maybeRunAfterEventTrigger('afterEvent', className, res);
             })
             .then(
-              () => {
+              async () => {
                 if (!res.sendEvent) {
                   return;
                 }
@@ -323,16 +324,14 @@ class ParseLiveQueryServer {
                   originalParseObject = res.original.toJSON();
                   originalParseObject.className = res.original.className || className;
                 }
-                if (
-                  (currentParseObject.className === '_User' ||
-                    currentParseObject.className === '_Session') &&
-                  !client.hasMasterKey
-                ) {
-                  delete currentParseObject.sessionToken;
-                  delete originalParseObject?.sessionToken;
-                  delete currentParseObject.authData;
-                  delete originalParseObject?.authData;
-                }
+                await this._filterSensitiveData(
+                  classLevelPermissions,
+                  res,
+                  client,
+                  requestId,
+                  op,
+                  subscription.query
+                );
                 const functionName =
                   'push' + message.event.charAt(0).toUpperCase() + message.event.slice(1);
                 if (client[functionName]) {
@@ -532,6 +531,53 @@ class ParseLiveQueryServer {
     // return rolesQuery.find({useMasterKey:true});
   }
 
+  async _filterSensitiveData(
+    classLevelPermissions: ?any,
+    res: any,
+    client: any,
+    requestId: number,
+    op: string,
+    query: any
+  ) {
+    const subscriptionInfo = client.getSubscriptionInfo(requestId);
+    const aclGroup = ['*'];
+    let clientAuth;
+    if (typeof subscriptionInfo !== 'undefined') {
+      const { userId, auth } = await this.getAuthForSessionToken(subscriptionInfo.sessionToken);
+      if (userId) {
+        aclGroup.push(userId);
+      }
+      clientAuth = auth;
+    }
+    const filter = obj => {
+      if (!obj) {
+        return;
+      }
+      let protectedFields = classLevelPermissions?.protectedFields || [];
+      if (!client.hasMasterKey && !Array.isArray(protectedFields)) {
+        protectedFields = getDatabaseController(this.config).addProtectedFields(
+          classLevelPermissions,
+          res.object.className,
+          query,
+          aclGroup,
+          clientAuth
+        );
+      }
+      return DatabaseController.filterSensitiveData(
+        client.hasMasterKey,
+        aclGroup,
+        clientAuth,
+        op,
+        classLevelPermissions,
+        res.object.className,
+        protectedFields,
+        obj
+      );
+    };
+    res.object = filter(res.object);
+    res.original = filter(res.original);
+  }
+
   _getCLPOperation(query: any) {
     return typeof query === 'object' &&
       Object.keys(query).length == 1 &&