Fix: Avoids prototype pollution (#7)

.eslintrc

@@ -1,29 +1,6 @@
 {
-  "env": {
-    "node": true
-  },
+  "extends": "gulp",
   "rules": {
-    "array-bracket-spacing": [2, "never"],
-    "block-scoped-var": 2,
-    "brace-style": [2, "1tbs"],
-    "camelcase": 1,
-    "computed-property-spacing": [2, "never"],
-    "curly": 2,
-    "eol-last": 2,
-    "eqeqeq": [2, "smart"],
-    "max-depth": [1, 3],
-    "max-len": [1, 80],
-    "max-statements": [1, 40],
-    "new-cap": 1,
-    "no-extend-native": 2,
-    "no-mixed-spaces-and-tabs": 2,
-    "no-trailing-spaces": 2,
-    "no-unused-vars": 1,
-    "no-use-before-define": [2, "nofunc"],
-    "object-curly-spacing": [2, "always"],
-    "quotes": [2, "single", "avoid-escape"],
-    "semi": [2, "always"],
-    "keyword-spacing": [2, { "before": true, "after": true }],
-    "space-unary-ops": 2
+    "max-statements": 0
   }
 }

index.js

@@ -184,6 +184,10 @@ function setDeep(obj, keyChain, valueCreator) {
 
 function _setDeep(obj, keyElems, depth, valueCreator) {
   var key = keyElems.shift();
+  if (isPossibilityOfPrototypePollution(key)) {
+    return;
+  }
+
   if (!keyElems.length) {
     var value = valueCreator(obj, key, depth);
     if (value === undefined) {
@@ -224,3 +228,7 @@ function newUndefined() {
 function isObject(v) {
   return Object.prototype.toString.call(v) === '[object Object]';
 }
+
+function isPossibilityOfPrototypePollution(key) {
+  return (key === '__proto__' || key === 'constructor');
+}

package.json

@@ -43,6 +43,7 @@
     "chai": "^3.5.0",
     "coveralls": "^3.1.0",
     "eslint": "^7.9.0",
+    "eslint-config-gulp": "^5.0.1",
     "mocha": "^3.5.3",
     "nyc": "^15.1.0",
     "uglify-js": "^3.10.4"

test/copy-props-proc.js

@@ -701,4 +701,106 @@ describe('Processing', function() {
 
   });
 
+  describe('Avoid a prototype pollution vulnerability', function() {
+
+    describe('The critical property key is in a src object', function() {
+
+      it('should ignore a property key: __proto__', function(done) {
+        var maliciousSrcJson = '{"__proto__":{"polluted":"polluted"},"a":1}';
+        expect({}.polluted).to.be.undefined;
+        expect(copyProps(JSON.parse(maliciousSrcJson), {})).to.deep.equal({ a: 1 });
+        expect({}.polluted).to.be.undefined;
+        done();
+      });
+
+      it('should ignore a property key: constructor.prototype', function(done) {
+        var maliciousSrcJson = '{"constructor":{"prototype":{"polluted":"polluted"}},"a":1}';
+        expect({}.polluted).to.be.undefined;
+        expect(copyProps(JSON.parse(maliciousSrcJson), {})).to.deep.equal({ a: 1 });
+        expect({}.polluted).to.be.undefined;
+        done();
+      });
+
+    });
+
+    describe('The critical property key is in a dest object and using reverse', function() {
+
+      it('should ignore a property key: __proto__', function(done) {
+        var maliciousSrcJson = '{"__proto__":{"polluted":"polluted"},"a":1}';
+        expect({}.polluted).to.be.undefined;
+        expect(copyProps({}, JSON.parse(maliciousSrcJson), true)).to.deep.equal({ a: 1 });
+        expect({}.polluted).to.be.undefined;
+        done();
+      });
+
+      it('should ignore a property key: constructor.prototype', function(done) {
+        var maliciousSrcJson = '{"constructor":{"prototype":{"polluted":"polluted"}},"a":1}';
+        expect({}.polluted).to.be.undefined;
+        expect(copyProps({}, JSON.parse(maliciousSrcJson), true)).to.deep.equal({ a: 1 });
+        expect({}.polluted).to.be.undefined;
+        done();
+      });
+
+    });
+
+    describe('The critical property value is in a fromto object', function() {
+
+      it('should ignore a property value: __proto__', function(done) {
+        var fromto = { a: '__proto__.poluuted', b: 'c' };
+        expect({}.polluted).to.be.undefined;
+        expect(copyProps({ a: 'polluted', b: 1 }, {}, fromto)).to.deep.equal({ c: 1 });
+        expect({}.polluted).to.be.undefined;
+        done();
+      });
+
+      it('should ignore a property value: constructor.prototype', function(done) {
+        var fromto = { a: 'constructor.prototype.polluted', b: 'c' };
+        expect({}.polluted).to.be.undefined;
+        expect(copyProps({ a: 'polluted', b: 1 }, {}, fromto)).to.deep.equal({ c: 1 });
+        expect({}.polluted).to.be.undefined;
+        done();
+      });
+
+    });
+
+    describe('The critical property key is in a fromto object and using reverse', function() {
+
+      it('should ignore a property key: __proto__', function(done) {
+        var fromto = { '__proto__.poluuted': 'a', c: 'b' };
+        expect({}.polluted).to.be.undefined;
+        expect(copyProps({}, { a: 'polluted', b: 1 }, fromto, true)).to.deep.equal({ c: 1 });
+        expect({}.polluted).to.be.undefined;
+        done();
+      });
+
+      it('should ignore a property key: constructor.prototype and using reverse', function(done) {
+        var fromto = { 'constructor.prototype.polluted': 'a', c: 'b' };
+        expect({}.polluted).to.be.undefined;
+        expect(copyProps({}, { a: 'polluted', b: 1 }, fromto, true)).to.deep.equal({ c: 1 });
+        expect({}.polluted).to.be.undefined;
+        done();
+      });
+
+    });
+
+    describe('The critical element is in a fromto array', function() {
+
+      it('should ignore an element: __proto__', function(done) {
+        var fromto = ['__proto__.polluted', 'b'];
+        expect({}.polluted).to.be.undefined;
+        expect(copyProps(JSON.parse('{"__proto__":{"polluted":"polluted"},"b":1}'), {}, fromto)).to.deep.equal({ b: 1 });
+        expect({}.polluted).to.be.undefined;
+        done();
+      });
+
+      it('should ignore an element: constructor.prototype', function(done) {
+        var fromto = ['constructor.prototype.polluted', 'b'];
+        expect({}.polluted).to.be.undefined;
+        expect(copyProps(JSON.parse('{"constructor":{"prototype":{"polluted":"polluted"}},"b":1}'), {}, fromto)).to.deep.equal({ b: 1 });
+        expect({}.polluted).to.be.undefined;
+        done();
+      });
+
+    });
+  });
 });

test/web/copy-props-proc.js

@@ -701,4 +701,106 @@ describe('Processing', function() {
 
   });
 
+  describe('Avoid a prototype pollution vulnerability', function() {
+
+    describe('The critical property key is in a src object', function() {
+
+      it('should ignore a property key: __proto__', function(done) {
+        var maliciousSrcJson = '{"__proto__":{"polluted":"polluted"},"a":1}';
+        expect({}.polluted).to.be.undefined;
+        expect(copyProps(JSON.parse(maliciousSrcJson), {})).to.deep.equal({ a: 1 });
+        expect({}.polluted).to.be.undefined;
+        done();
+      });
+
+      it('should ignore a property key: constructor.prototype', function(done) {
+        var maliciousSrcJson = '{"constructor":{"prototype":{"polluted":"polluted"}},"a":1}';
+        expect({}.polluted).to.be.undefined;
+        expect(copyProps(JSON.parse(maliciousSrcJson), {})).to.deep.equal({ a: 1 });
+        expect({}.polluted).to.be.undefined;
+        done();
+      });
+
+    });
+
+    describe('The critical property key is in a dest object and using reverse', function() {
+
+      it('should ignore a property key: __proto__', function(done) {
+        var maliciousSrcJson = '{"__proto__":{"polluted":"polluted"},"a":1}';
+        expect({}.polluted).to.be.undefined;
+        expect(copyProps({}, JSON.parse(maliciousSrcJson), true)).to.deep.equal({ a: 1 });
+        expect({}.polluted).to.be.undefined;
+        done();
+      });
+
+      it('should ignore a property key: constructor.prototype', function(done) {
+        var maliciousSrcJson = '{"constructor":{"prototype":{"polluted":"polluted"}},"a":1}';
+        expect({}.polluted).to.be.undefined;
+        expect(copyProps({}, JSON.parse(maliciousSrcJson), true)).to.deep.equal({ a: 1 });
+        expect({}.polluted).to.be.undefined;
+        done();
+      });
+
+    });
+
+    describe('The critical property value is in a fromto object', function() {
+
+      it('should ignore a property value: __proto__', function(done) {
+        var fromto = { a: '__proto__.poluuted', b: 'c' };
+        expect({}.polluted).to.be.undefined;
+        expect(copyProps({ a: 'polluted', b: 1 }, {}, fromto)).to.deep.equal({ c: 1 });
+        expect({}.polluted).to.be.undefined;
+        done();
+      });
+
+      it('should ignore a property value: constructor.prototype', function(done) {
+        var fromto = { a: 'constructor.prototype.polluted', b: 'c' };
+        expect({}.polluted).to.be.undefined;
+        expect(copyProps({ a: 'polluted', b: 1 }, {}, fromto)).to.deep.equal({ c: 1 });
+        expect({}.polluted).to.be.undefined;
+        done();
+      });
+
+    });
+
+    describe('The critical property key is in a fromto object and using reverse', function() {
+
+      it('should ignore a property key: __proto__', function(done) {
+        var fromto = { '__proto__.poluuted': 'a', c: 'b' };
+        expect({}.polluted).to.be.undefined;
+        expect(copyProps({}, { a: 'polluted', b: 1 }, fromto, true)).to.deep.equal({ c: 1 });
+        expect({}.polluted).to.be.undefined;
+        done();
+      });
+
+      it('should ignore a property key: constructor.prototype and using reverse', function(done) {
+        var fromto = { 'constructor.prototype.polluted': 'a', c: 'b' };
+        expect({}.polluted).to.be.undefined;
+        expect(copyProps({}, { a: 'polluted', b: 1 }, fromto, true)).to.deep.equal({ c: 1 });
+        expect({}.polluted).to.be.undefined;
+        done();
+      });
+
+    });
+
+    describe('The critical element is in a fromto array', function() {
+
+      it('should ignore an element: __proto__', function(done) {
+        var fromto = ['__proto__.polluted', 'b'];
+        expect({}.polluted).to.be.undefined;
+        expect(copyProps(JSON.parse('{"__proto__":{"polluted":"polluted"},"b":1}'), {}, fromto)).to.deep.equal({ b: 1 });
+        expect({}.polluted).to.be.undefined;
+        done();
+      });
+
+      it('should ignore an element: constructor.prototype', function(done) {
+        var fromto = ['constructor.prototype.polluted', 'b'];
+        expect({}.polluted).to.be.undefined;
+        expect(copyProps(JSON.parse('{"constructor":{"prototype":{"polluted":"polluted"}},"b":1}'), {}, fromto)).to.deep.equal({ b: 1 });
+        expect({}.polluted).to.be.undefined;
+        done();
+      });
+
+    });
+  });
 });

web/copy-props.js

@@ -185,6 +185,10 @@ function setDeep(obj, keyChain, valueCreator) {
 
 function _setDeep(obj, keyElems, depth, valueCreator) {
   var key = keyElems.shift();
+  if (isPossibilityOfPrototypePollution(key)) {
+    return;
+  }
+
   if (!keyElems.length) {
     var value = valueCreator(obj, key, depth);
     if (value === undefined) {
@@ -226,6 +230,10 @@ function isObject(v) {
   return Object.prototype.toString.call(v) === '[object Object]';
 }
 
+function isPossibilityOfPrototypePollution(key) {
+  return (key === '__proto__' || key === 'constructor');
+}
+
 },{"each-props":4,"is-plain-object":8}],2:[function(require,module,exports){
 /*!
  * array-each <https://github.com/jonschlinkert/array-each>