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// Copyright (c) 2012 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 "build/build_config.h"
#if defined(OS_WIN)
#include <objbase.h>
#include <windows.h>
#endif
#include "base/bind.h"
#include "base/command_line.h"
#include "base/message_loop.h"
#include "base/string_util.h"
#include "base/system_monitor/system_monitor.h"
#include "base/threading/platform_thread.h"
#include "content/common/child_process.h"
#include "content/common/hi_res_timer_manager.h"
#include "content/plugin/plugin_thread.h"
#include "content/public/common/content_switches.h"
#include "content/public/common/main_function_params.h"
#if defined(OS_WIN)
#include "content/common/injection_test_dll.h"
#include "sandbox/src/sandbox.h"
#elif defined(OS_POSIX) && !defined(OS_MACOSX)
#include "base/global_descriptors_posix.h"
#include "ipc/ipc_descriptors.h"
#endif
#if defined(OS_MACOSX)
// Removes our Carbon library interposing from the environment so that it
// doesn't carry into any processes that plugins might start.
void TrimInterposeEnvironment();
// Initializes the global Cocoa application object.
void InitializeChromeApplication();
#elif defined(OS_LINUX)
// Work around an unimplemented instruction in 64-bit Flash.
void WorkaroundFlashLAHF();
#endif
#if defined(OS_WIN)
// This function is provided so that the built-in flash can lock down the
// sandbox by calling DelayedLowerToken(0).
extern "C" DWORD __declspec(dllexport) __stdcall DelayedLowerToken(void* ts) {
// s_ts is only set the first time the function is called, which happens
// in PluginMain.
static sandbox::TargetServices* s_ts =
reinterpret_cast<sandbox::TargetServices*>(ts);
if (ts)
return 0;
s_ts->LowerToken();
return 1;
};
// Returns true if the plugin to be loaded is the internal flash.
bool IsPluginBuiltInFlash(const CommandLine& cmd_line) {
FilePath path = cmd_line.GetSwitchValuePath(switches::kPluginPath);
return (path.BaseName() == FilePath(L"gcswf32.dll"));
}
// Before we lock down the flash sandbox, we need to activate the IME machinery
// and attach it to this process. (Windows attaches an IME machinery to this
// process automatically while it creates its first top-level window.) After
// lock down it seems it is unable to start. Note that we leak the IME context
// on purpose.
HWND g_ime_window = NULL;
int PreloadIMEForFlash() {
HIMC imc = ::ImmCreateContext();
if (!imc)
return 0;
if (::ImmGetOpenStatus(imc))
return 1;
if (!g_ime_window) {
g_ime_window = CreateWindowEx(WS_EX_TOOLWINDOW, L"EDIT", L"", WS_POPUP,
0, 0, 0, 0, NULL, NULL, GetModuleHandle(NULL), NULL);
SetWindowLongPtr(g_ime_window, GWL_EXSTYLE, WS_EX_NOACTIVATE);
}
return 2;
}
void DestroyIMEForFlash() {
if (g_ime_window) {
DestroyWindow(g_ime_window);
g_ime_window = NULL;
}
}
// VirtualAlloc doesn't randomize well, so we use these calls to poke a
// random-sized hole in the address space and set an event to later remove it.
void FreeRandomMemoryHole(void *hole) {
::VirtualFree(hole, 0, MEM_RELEASE);
}
bool CreateRandomMemoryHole() {
const uint32_t kRandomValueMax = 8 * 1024; // Yields a 512mb max hole.
const uint32_t kRandomValueDivisor = 8;
const uint32_t kMaxWaitSeconds = 18 * 60; // 18 Minutes in seconds.
COMPILE_ASSERT((kMaxWaitSeconds > (kRandomValueMax / kRandomValueDivisor)),
kMaxWaitSeconds_value_too_small);
uint32_t rand_val;
if (rand_s(&rand_val) != S_OK) {
DVLOG(ERROR) << "rand_s() failed";
}
rand_val %= kRandomValueMax;
// Reserve a (randomly selected) range of address space.
if (void* hole = ::VirtualAlloc(NULL, 65536 * (1 + rand_val),
MEM_RESERVE, PAGE_NOACCESS)) {
// Set up an event to remove the memory hole. Base the wait time on the
// inverse of the allocation size, meaning a bigger hole gets a shorter
// wait (ranging from 1-18 minutes).
const uint32_t wait = kMaxWaitSeconds - (rand_val / kRandomValueDivisor);
MessageLoop::current()->PostDelayedTask(FROM_HERE,
base::Bind(&FreeRandomMemoryHole, hole),
base::TimeDelta::FromSeconds(wait));
return true;
}
return false;
}
#endif
// main() routine for running as the plugin process.
int PluginMain(const content::MainFunctionParams& parameters) {
// The main thread of the plugin services UI.
#if defined(OS_MACOSX)
#if !defined(__LP64__)
TrimInterposeEnvironment();
#endif
InitializeChromeApplication();
#endif
MessageLoop main_message_loop(MessageLoop::TYPE_UI);
base::PlatformThread::SetName("CrPluginMain");
base::SystemMonitor system_monitor;
HighResolutionTimerManager high_resolution_timer_manager;
const CommandLine& parsed_command_line = parameters.command_line;
#if defined(OS_LINUX)
#if defined(ARCH_CPU_64_BITS)
WorkaroundFlashLAHF();
#endif
#elif defined(OS_WIN)
sandbox::TargetServices* target_services =
parameters.sandbox_info->target_services;
CoInitialize(NULL);
DVLOG(1) << "Started plugin with "
<< parsed_command_line.GetCommandLineString();
HMODULE sandbox_test_module = NULL;
bool no_sandbox = parsed_command_line.HasSwitch(switches::kNoSandbox);
if (target_services && !no_sandbox) {
// The command line might specify a test plugin to load.
if (parsed_command_line.HasSwitch(switches::kTestSandbox)) {
std::wstring test_plugin_name =
parsed_command_line.GetSwitchValueNative(switches::kTestSandbox);
sandbox_test_module = LoadLibrary(test_plugin_name.c_str());
DCHECK(sandbox_test_module);
}
}
#endif
if (parsed_command_line.HasSwitch(switches::kPluginStartupDialog)) {
ChildProcess::WaitForDebugger("Plugin");
}
{
ChildProcess plugin_process;
plugin_process.set_main_thread(new PluginThread());
#if defined(OS_WIN)
if (!no_sandbox && target_services) {
// We are sandboxing the plugin. If it is a generic plug-in, we lock down
// the sandbox right away, but if it is the built-in flash we let flash
// start elevated and it will call DelayedLowerToken(0) when it's ready.
if (IsPluginBuiltInFlash(parsed_command_line)) {
DVLOG(1) << "Sandboxing flash";
// Poke hole in the address space to improve randomization.
if (!CreateRandomMemoryHole()) {
DVLOG(ERROR) << "Failed to create random memory hole";
}
if (!PreloadIMEForFlash())
DVLOG(1) << "IME preload failed";
DelayedLowerToken(target_services);
} else {
target_services->LowerToken();
}
}
if (sandbox_test_module) {
RunPluginTests run_security_tests =
reinterpret_cast<RunPluginTests>(GetProcAddress(sandbox_test_module,
kPluginTestCall));
DCHECK(run_security_tests);
if (run_security_tests) {
int test_count = 0;
DVLOG(1) << "Running plugin security tests";
BOOL result = run_security_tests(&test_count);
DCHECK(result) << "Test number " << test_count << " has failed.";
// If we are in release mode, crash or debug the process.
if (!result) {
__debugbreak();
_exit(1);
}
}
FreeLibrary(sandbox_test_module);
}
#endif
MessageLoop::current()->Run();
}
#if defined(OS_WIN)
DestroyIMEForFlash();
CoUninitialize();
#endif
return 0;
}
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