Harden creation of child processes (#55697)

Add general protection against RCE vulnerabilities similar to the one
described in CVE-2019-7609.

Closes #49605

.eslintrc.js

@@ -514,6 +514,16 @@ module.exports = {
       },
     },
 
+    /**
+     * Harden specific rules
+     */
+    {
+      files: ['test/harden/*.js'],
+      rules: {
+        'mocha/handle-done-callback': 'off', // TODO: Find a way to disable all mocha rules
+      },
+    },
+
     /**
      * APM overrides
      */

package.json

@@ -246,6 +246,7 @@
     "regenerator-runtime": "^0.13.3",
     "regression": "2.0.1",
     "request": "^2.88.0",
+    "require-in-the-middle": "^5.0.2",
     "reselect": "^4.0.0",
     "resize-observer-polyfill": "^1.5.0",
     "rison-node": "1.0.2",
@@ -480,6 +481,7 @@
     "strip-ansi": "^3.0.1",
     "supertest": "^3.1.0",
     "supertest-as-promised": "^4.0.2",
+    "tape": "^4.13.0",
     "tree-kill": "^1.2.2",
     "typescript": "3.7.2",
     "typings-tester": "^0.3.2",

scripts/test_hardening.js

@@ -0,0 +1,41 @@
+/*
+ * Licensed to Elasticsearch B.V. under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch B.V. licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+var execFileSync = require('child_process').execFileSync;
+var path = require('path');
+var syncGlob = require('glob').sync;
+var program = require('commander');
+
+program
+  .name('node scripts/test_hardening.js')
+  .arguments('[file...]')
+  .description(
+    'Run the tests in test/harden directory. If no files are provided, all files within the directory will be run.'
+  )
+  .action(function(globs) {
+    if (globs.length === 0) globs.push(path.join('test', 'harden', '*'));
+    globs.forEach(function(glob) {
+      syncGlob(glob).forEach(function(filename) {
+        if (path.basename(filename)[0] === '_') return;
+        console.log(process.argv[0], filename);
+        execFileSync(process.argv[0], [filename], { stdio: 'inherit' });
+      });
+    });
+  })
+  .parse(process.argv);

src/setup_node_env/harden.js

@@ -0,0 +1,24 @@
+/*
+ * Licensed to Elasticsearch B.V. under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch B.V. licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+var hook = require('require-in-the-middle');
+
+hook(['child_process'], function(exports, name) {
+  return require(`./patches/${name}`)(exports); // eslint-disable-line import/no-dynamic-require
+});

src/setup_node_env/index.js

@@ -17,6 +17,7 @@
  * under the License.
  */
 
+require('./harden'); // this require MUST be executed before any others
 require('symbol-observable');
 require('./root');
 require('./node_version_validator');

src/setup_node_env/patches/child_process.js

@@ -0,0 +1,76 @@
+/*
+ * Licensed to Elasticsearch B.V. under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch B.V. licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+// Ensure, when spawning a new child process, that the `options` and the
+// `options.env` object passed to the child process function doesn't inherit
+// from `Object.prototype`. This protects against similar RCE vulnerabilities
+// as described in CVE-2019-7609
+module.exports = function(cp) {
+  // The `exec` function is currently just a wrapper around `execFile`. So for
+  // now there's no need to patch it. If this changes in the future, our tests
+  // will fail and we can uncomment the line below.
+  //
+  // cp.exec = new Proxy(cp.exec, { apply: patchOptions() });
+
+  cp.execFile = new Proxy(cp.execFile, { apply: patchOptions(true) });
+  cp.fork = new Proxy(cp.fork, { apply: patchOptions(true) });
+  cp.spawn = new Proxy(cp.spawn, { apply: patchOptions(true) });
+  cp.execFileSync = new Proxy(cp.execFileSync, { apply: patchOptions(true) });
+  cp.execSync = new Proxy(cp.execSync, { apply: patchOptions() });
+  cp.spawnSync = new Proxy(cp.spawnSync, { apply: patchOptions(true) });
+
+  return cp;
+};
+
+function patchOptions(hasArgs) {
+  return function apply(target, thisArg, args) {
+    var pos = 1;
+    if (pos === args.length) {
+      // fn(arg1)
+      args[pos] = prototypelessSpawnOpts();
+    } else if (pos < args.length) {
+      if (hasArgs && (Array.isArray(args[pos]) || args[pos] == null)) {
+        // fn(arg1, args, ...)
+        pos++;
+      }
+
+      if (typeof args[pos] === 'object' && args[pos] !== null) {
+        // fn(arg1, {}, ...)
+        // fn(arg1, args, {}, ...)
+        args[pos] = prototypelessSpawnOpts(args[pos]);
+      } else if (args[pos] == null) {
+        // fn(arg1, null/undefined, ...)
+        // fn(arg1, args, null/undefined, ...)
+        args[pos] = prototypelessSpawnOpts();
+      } else if (typeof args[pos] === 'function') {
+        // fn(arg1, callback)
+        // fn(arg1, args, callback)
+        args.splice(pos, 0, prototypelessSpawnOpts());
+      }
+    }
+
+    return target.apply(thisArg, args);
+  };
+}
+
+function prototypelessSpawnOpts(obj) {
+  var prototypelessObj = Object.assign(Object.create(null), obj);
+  prototypelessObj.env = Object.assign(Object.create(null), prototypelessObj.env || process.env);
+  return prototypelessObj;
+}

tasks/config/run.js

@@ -210,6 +210,12 @@ module.exports = function(grunt) {
       args: ['scripts/notice', '--validate'],
     }),
 
+    test_hardening: scriptWithGithubChecks({
+      title: 'Node.js hardening tests',
+      cmd: NODE,
+      args: ['scripts/test_hardening.js'],
+    }),
+
     apiIntegrationTests: scriptWithGithubChecks({
       title: 'API integration tests',
       cmd: NODE,

tasks/jenkins.js

@@ -37,6 +37,7 @@ module.exports = function(grunt) {
     'run:test_jest_integration',
     'run:test_projects',
     'run:test_karma_ci',
+    'run:test_hardening',
     'run:apiIntegrationTests',
   ]);
 };

test/harden/_echo.sh

@@ -0,0 +1,3 @@
+#!/usr/bin/env sh
+
+echo $POLLUTED$custom

test/harden/_fork.js

@@ -0,0 +1,20 @@
+/*
+ * Licensed to Elasticsearch B.V. under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch B.V. licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+console.log(`${process.env.POLLUTED || ''}${process.env.custom || ''}`);