// Copyright 2013 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.
#ifndef COMPONENTS_NACL_BROWSER_NACL_BROWSER_H_
#define COMPONENTS_NACL_BROWSER_NACL_BROWSER_H_
#include <deque>
#include "base/bind.h"
#include "base/containers/mru_cache.h"
#include "base/files/file.h"
#include "base/files/file_util_proxy.h"
#include "base/memory/singleton.h"
#include "base/memory/weak_ptr.h"
#include "base/platform_file.h"
#include "base/time/time.h"
#include "components/nacl/browser/nacl_browser_delegate.h"
#include "components/nacl/browser/nacl_validation_cache.h"
class URLPattern;
class GURL;
namespace nacl {
// Open an immutable executable file that can be mmapped.
// This function should only be called on a thread that can perform file IO.
base::File OpenNaClExecutableImpl(const base::FilePath& file_path);
// Represents shared state for all NaClProcessHost objects in the browser.
class NaClBrowser {
public:
static NaClBrowser* GetInstance();
// Will it be possible to launch a NaCl process, eventually?
bool IsOk() const;
// Are we ready to launch a NaCl process now? Implies IsOk().
bool IsReady() const;
// Attempt to asynchronously acquire all resources needed to start a process.
// This method is idempotent - it is safe to call multiple times.
void EnsureAllResourcesAvailable();
// Enqueues reply() in the message loop when all the resources needed to start
// a process have been acquired.
void WaitForResources(const base::Closure& reply);
// Asynchronously attempt to get the IRT open.
// This is entailed by EnsureInitialized. This method is exposed as part of
// the public interface, however, so the IRT can be explicitly opened as
// early as possible to prevent autoupdate issues.
void EnsureIrtAvailable();
// Path to IRT. Available even before IRT is loaded.
const base::FilePath& GetIrtFilePath();
// IRT file handle, only available when IsReady().
base::PlatformFile IrtFile() const;
// Methods for testing GDB debug stub in browser. If test adds debug stub
// port listener, Chrome will allocate a currently-unused TCP port number for
// debug stub server instead of a fixed one.
// Notify listener that new debug stub TCP port is allocated.
void FireGdbDebugStubPortOpened(int port);
bool HasGdbDebugStubPortListener();
void SetGdbDebugStubPortListener(base::Callback<void(int)> listener);
void ClearGdbDebugStubPortListener();
bool ValidationCacheIsEnabled() const {
return validation_cache_is_enabled_;
}
const std::string& GetValidationCacheKey() const {
return validation_cache_.GetValidationCacheKey();
}
// The NaCl singleton keeps information about NaCl executable files opened via
// PPAPI. This allows the NaCl process to get trusted information about the
// file directly from the browser process. In theory, a compromised renderer
// could provide a writable file handle or lie about the file's path. If we
// trusted the handle was read only but it was not, an mmapped file could be
// modified after validation, allowing an escape from the NaCl sandbox.
// Similarly, if we trusted the file path corresponded to the file handle but
// it did not, the validation cache could be tricked into bypassing validation
// for bad code.
// Instead of allowing these attacks, the NaCl process only trusts information
// it gets directly from the browser process. Because the information is
// stored in a cache of bounded size, it is not guaranteed the browser process
// will be able to provide the requested information. In these cases, the
// NaCl process must make conservative assumptions about the origin of the
// file.
// In theory, a compromised renderer could guess file tokens in an attempt to
// read files it normally doesn't have access to. This would not compromise
// the NaCl sandbox, however, and only has a 1 in ~2**120 chance of success
// per guess.
// TODO(ncbray): move the cache onto NaClProcessHost so that we don't need to
// rely on tokens being unguessable by another process.
void PutFilePath(const base::FilePath& path, uint64* file_token_lo,
uint64* file_token_hi);
bool GetFilePath(uint64 file_token_lo, uint64 file_token_hi,
base::FilePath* path);
bool QueryKnownToValidate(const std::string& signature, bool off_the_record);
void SetKnownToValidate(const std::string& signature, bool off_the_record);
void ClearValidationCache(const base::Closure& callback);
#if defined(OS_WIN)
// Get path to NaCl loader on the filesystem if possible.
// |exe_path| does not change if the method fails.
bool GetNaCl64ExePath(base::FilePath* exe_path);
#endif
void EarlyStartup();
static void SetDelegate(NaClBrowserDelegate* delegate);
static NaClBrowserDelegate* GetDelegate();
// Support for NaCl crash throttling.
// Each time a NaCl module crashes, the browser is notified.
void OnProcessCrashed();
// If "too many" crashes occur within a given time period, NaCl is throttled
// until the rate again drops below the threshold.
bool IsThrottled();
private:
friend struct DefaultSingletonTraits<NaClBrowser>;
enum NaClResourceState {
NaClResourceUninitialized,
NaClResourceRequested,
NaClResourceReady
};
NaClBrowser();
~NaClBrowser();
void InitIrtFilePath();
void OpenIrtLibraryFile();
void OnIrtOpened(base::File::Error error_code,
base::PassPlatformFile file, bool created);
void InitValidationCacheFilePath();
void EnsureValidationCacheAvailable();
void OnValidationCacheLoaded(const std::string* data);
void RunWithoutValidationCache();
// Dispatch waiting tasks if we are ready, or if we know we'll never be ready.
void CheckWaiting();
// Indicate that it is impossible to launch a NaCl process.
void MarkAsFailed();
void MarkValidationCacheAsModified();
void PersistValidationCache();
// Singletons get destroyed at shutdown.
base::WeakPtrFactory<NaClBrowser> weak_factory_;
base::PlatformFile irt_platform_file_;
base::FilePath irt_filepath_;
NaClResourceState irt_state_;
NaClValidationCache validation_cache_;
NaClValidationCache off_the_record_validation_cache_;
base::FilePath validation_cache_file_path_;
bool validation_cache_is_enabled_;
bool validation_cache_is_modified_;
NaClResourceState validation_cache_state_;
base::Callback<void(int)> debug_stub_port_listener_;
typedef base::HashingMRUCache<std::string, base::FilePath> PathCacheType;
PathCacheType path_cache_;
bool ok_;
// A list of pending tasks to start NaCl processes.
std::vector<base::Closure> waiting_;
scoped_ptr<NaClBrowserDelegate> browser_delegate_;
std::deque<base::Time> crash_times_;
DISALLOW_COPY_AND_ASSIGN(NaClBrowser);
};
} // namespace nacl
#endif // COMPONENTS_NACL_BROWSER_NACL_BROWSER_H_