blob: 24514d434f5e3f72ef5e13ce14051a0769186f9f [file] [log] [blame]
// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "extensions/renderer/safe_builtins.h"
#include "base/logging.h"
#include "base/stl_util.h"
#include "base/strings/stringprintf.h"
#include "extensions/renderer/script_context.h"
#include "extensions/renderer/v8_helpers.h"
namespace extensions {
using namespace v8_helpers;
namespace {
const char kClassName[] = "extensions::SafeBuiltins";
// Documentation for makeCallback in the JavaScript, out here to reduce the
// (very small) amount of effort that the v8 parser needs to do:
//
// Returns a new object with every function on |obj| configured to call()
// itself with the given arguments.
// E.g. given
// var result = makeCallable(Function.prototype)
// |result| will be a object including 'bind' such that
// result.bind(foo, 1, 2, 3);
// is equivalent to Function.prototype.bind.call(foo, 1, 2, 3), and so on.
// This is a convenient way to save functions that user scripts may clobber.
const char kScript[] =
"(function() {\n"
"'use strict';\n"
"native function Apply();\n"
"native function Save();\n"
"\n"
"// Used in the callback implementation, could potentially be clobbered.\n"
"function makeCallable(obj, target, isStatic, propertyNames) {\n"
" propertyNames.forEach(function(propertyName) {\n"
" var property = obj[propertyName];\n"
" target[propertyName] = function() {\n"
" var recv = obj;\n"
" var firstArgIndex = 0;\n"
" if (!isStatic) {\n"
" if (arguments.length == 0)\n"
" throw 'There must be at least one argument, the receiver';\n"
" recv = arguments[0];\n"
" firstArgIndex = 1;\n"
" }\n"
" return Apply(\n"
" property, recv, arguments, firstArgIndex, arguments.length);\n"
" };\n"
" });\n"
"}\n"
"\n"
"function saveBuiltin(builtin, protoPropertyNames, staticPropertyNames) {\n"
" var safe = function() {\n"
" throw 'Safe objects cannot be called nor constructed. ' +\n"
" 'Use $Foo.self() or new $Foo.self() instead.';\n"
" };\n"
" safe.self = builtin;\n"
" makeCallable(builtin.prototype, safe, false, protoPropertyNames);\n"
" if (staticPropertyNames)\n"
" makeCallable(builtin, safe, true, staticPropertyNames);\n"
" Save(builtin.name, safe);\n"
"}\n"
"\n"
"// Save only what is needed by the extension modules.\n"
"saveBuiltin(Object,\n"
" ['hasOwnProperty'],\n"
" ['create', 'defineProperty', 'freeze',\n"
" 'getOwnPropertyDescriptor', 'getPrototypeOf', 'keys',\n"
" 'assign', 'setPrototypeOf']);\n"
"saveBuiltin(Function,\n"
" ['apply', 'bind', 'call']);\n"
"saveBuiltin(Array,\n"
" ['concat', 'forEach', 'indexOf', 'join', 'push', 'slice',\n"
" 'splice', 'map', 'filter', 'shift', 'unshift', 'pop',\n"
" 'reverse'],\n"
" ['from', 'isArray']);\n"
"saveBuiltin(String,\n"
" ['indexOf', 'slice', 'split', 'substr', 'toLowerCase',\n"
" 'toUpperCase', 'replace']);\n"
"// Use exec rather than test to defend against clobbering in the\n"
"// presence of ES2015 semantics, which read RegExp.prototype.exec.\n"
"saveBuiltin(RegExp,\n"
" ['exec']);\n"
"saveBuiltin(Error,\n"
" [],\n"
" ['captureStackTrace']);\n"
"\n"
"// JSON is trickier because extensions can override toJSON in\n"
"// incompatible ways, and we need to prevent that.\n"
"var builtinTypes = [\n"
" Object, Function, Array, String, Boolean, Number, Date, RegExp\n"
"];\n"
"var builtinToJSONs = builtinTypes.map(function(t) {\n"
" return t.toJSON;\n"
"});\n"
"var builtinArray = Array;\n"
"var builtinJSONStringify = JSON.stringify;\n"
"Save('JSON', {\n"
" parse: JSON.parse,\n"
" stringify: function(obj) {\n"
" var savedToJSONs = new builtinArray(builtinTypes.length);\n"
" try {\n"
" for (var i = 0; i < builtinTypes.length; ++i) {\n"
" try {\n"
" if (builtinTypes[i].prototype.toJSON !==\n"
" builtinToJSONs[i]) {\n"
" savedToJSONs[i] = builtinTypes[i].prototype.toJSON;\n"
" builtinTypes[i].prototype.toJSON = builtinToJSONs[i];\n"
" }\n"
" } catch (e) {}\n"
" }\n"
" } catch (e) {}\n"
" try {\n"
" return builtinJSONStringify(obj);\n"
" } finally {\n"
" for (var i = 0; i < builtinTypes.length; ++i) {\n"
" try {\n"
" if (i in savedToJSONs)\n"
" builtinTypes[i].prototype.toJSON = savedToJSONs[i];\n"
" } catch (e) {}\n"
" }\n"
" }\n"
" }\n"
"});\n"
"\n"
"}());\n";
v8::Local<v8::Private> MakeKey(const char* name, v8::Isolate* isolate) {
return v8::Private::ForApi(
isolate, ToV8StringUnsafe(
isolate, base::StringPrintf("%s::%s", kClassName, name)));
}
void SaveImpl(const char* name,
v8::Local<v8::Value> value,
v8::Local<v8::Context> context) {
CHECK(!value.IsEmpty() && value->IsObject()) << name;
context->Global()
->SetPrivate(context, MakeKey(name, context->GetIsolate()), value)
.FromJust();
}
v8::Local<v8::Object> Load(const char* name, v8::Local<v8::Context> context) {
v8::Local<v8::Value> value =
context->Global()
->GetPrivate(context, MakeKey(name, context->GetIsolate()))
.ToLocalChecked();
CHECK(value->IsObject()) << name;
return v8::Local<v8::Object>::Cast(value);
}
class ExtensionImpl : public v8::Extension {
public:
ExtensionImpl() : v8::Extension(kClassName, kScript) {}
private:
v8::Local<v8::FunctionTemplate> GetNativeFunctionTemplate(
v8::Isolate* isolate,
v8::Local<v8::String> name) override {
v8::Local<v8::Context> context = isolate->GetCurrentContext();
if (IsTrue(name->Equals(context, ToV8StringUnsafe(isolate, "Apply"))))
return v8::FunctionTemplate::New(isolate, Apply);
if (IsTrue(name->Equals(context, ToV8StringUnsafe(isolate, "Save"))))
return v8::FunctionTemplate::New(isolate, Save);
NOTREACHED() << *v8::String::Utf8Value(isolate, name);
return v8::Local<v8::FunctionTemplate>();
}
static void Apply(const v8::FunctionCallbackInfo<v8::Value>& info) {
CHECK(info.Length() == 5 && info[0]->IsFunction() && // function
// info[1] could be an object or a string
info[2]->IsObject() && // args
info[3]->IsInt32() && // first_arg_index
info[4]->IsInt32()); // args_length
v8::Local<v8::Function> function = info[0].As<v8::Function>();
v8::Local<v8::Object> recv;
if (info[1]->IsObject()) {
recv = v8::Local<v8::Object>::Cast(info[1]);
} else if (info[1]->IsString()) {
recv = v8::StringObject::New(v8::Local<v8::String>::Cast(info[1]))
.As<v8::Object>();
} else {
info.GetIsolate()->ThrowException(
v8::Exception::TypeError(ToV8StringUnsafe(
info.GetIsolate(),
"The first argument is the receiver and must be an object")));
return;
}
v8::Local<v8::Object> args = v8::Local<v8::Object>::Cast(info[2]);
int first_arg_index = info[3].As<v8::Int32>()->Value();
int args_length = info[4].As<v8::Int32>()->Value();
v8::Local<v8::Context> context = info.GetIsolate()->GetCurrentContext();
int argc = args_length - first_arg_index;
std::unique_ptr<v8::Local<v8::Value>[]> argv(
new v8::Local<v8::Value>[argc]);
for (int i = 0; i < argc; ++i) {
CHECK(IsTrue(args->Has(context, i + first_arg_index)));
// Getting a property value could throw an exception.
if (!GetProperty(context, args, i + first_arg_index, &argv[i]))
return;
}
v8::MicrotasksScope microtasks(
info.GetIsolate(), v8::MicrotasksScope::kDoNotRunMicrotasks);
v8::Local<v8::Value> return_value;
if (function->Call(context, recv, argc, argv.get()).ToLocal(&return_value))
info.GetReturnValue().Set(return_value);
}
static void Save(const v8::FunctionCallbackInfo<v8::Value>& info) {
CHECK(info.Length() == 2 && info[0]->IsString() && info[1]->IsObject());
SaveImpl(*v8::String::Utf8Value(info.GetIsolate(), info[0]), info[1],
info.GetIsolate()->GetCurrentContext());
}
};
} // namespace
// static
v8::Extension* SafeBuiltins::CreateV8Extension() { return new ExtensionImpl(); }
SafeBuiltins::SafeBuiltins(ScriptContext* context) : context_(context) {}
SafeBuiltins::~SafeBuiltins() {}
v8::Local<v8::Object> SafeBuiltins::GetArray() const {
return Load("Array", context_->v8_context());
}
v8::Local<v8::Object> SafeBuiltins::GetFunction() const {
return Load("Function", context_->v8_context());
}
v8::Local<v8::Object> SafeBuiltins::GetJSON() const {
return Load("JSON", context_->v8_context());
}
v8::Local<v8::Object> SafeBuiltins::GetObjekt() const {
return Load("Object", context_->v8_context());
}
v8::Local<v8::Object> SafeBuiltins::GetRegExp() const {
return Load("RegExp", context_->v8_context());
}
v8::Local<v8::Object> SafeBuiltins::GetString() const {
return Load("String", context_->v8_context());
}
v8::Local<v8::Object> SafeBuiltins::GetError() const {
return Load("Error", context_->v8_context());
}
} // namespace extensions