components/nacl/loader/nacl_listener.cc

   1 // Copyright 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "components/nacl/loader/nacl_listener.h"
   6
   7 #include <errno.h>
   8 #include <fcntl.h>
   9 #include <stdlib.h>
  10 #include <string.h>
  11
  12 #if defined(OS_POSIX)
  13 #include <unistd.h>
  14 #endif
  15
  16 #include "base/command_line.h"
  17 #include "base/logging.h"
  18 #include "base/memory/scoped_ptr.h"
  19 #include "base/message_loop/message_loop.h"
  20 #include "base/rand_util.h"
  21 #include "components/nacl/common/nacl_messages.h"
  22 #include "components/nacl/common/nacl_renderer_messages.h"
  23 #include "components/nacl/common/nacl_switches.h"
  24 #include "components/nacl/loader/nacl_ipc_adapter.h"
  25 #include "components/nacl/loader/nacl_validation_db.h"
  26 #include "components/nacl/loader/nacl_validation_query.h"
  27 #include "ipc/ipc_channel_handle.h"
  28 #include "ipc/ipc_switches.h"
  29 #include "ipc/ipc_sync_channel.h"
  30 #include "ipc/ipc_sync_message_filter.h"
  31 #include "mojo/nacl/mojo_syscall.h"
  32 #include "native_client/src/public/chrome_main.h"
  33 #include "native_client/src/public/nacl_app.h"
  34 #include "native_client/src/public/nacl_desc.h"
  35 #include "third_party/mojo/src/mojo/edk/embedder/embedder.h"
  36 #include "third_party/mojo/src/mojo/edk/embedder/platform_support.h"
  37 #include "third_party/mojo/src/mojo/edk/embedder/simple_platform_support.h"
  38
  39 #if defined(OS_POSIX)
  40 #include "base/file_descriptor_posix.h"
  41 #endif
  42
  43 #if defined(OS_LINUX)
  44 #include "content/public/common/child_process_sandbox_support_linux.h"
  45 #endif
  46
  47 #if defined(OS_WIN)
  48 #include <io.h>
  49
  50 #include "content/public/common/sandbox_init.h"
  51 #endif
  52
  53 namespace {
  54
  55 NaClListener* g_listener;
  56
  57 void FatalLogHandler(const char* data, size_t bytes) {
  58   // We use uint32_t rather than size_t for the case when the browser and NaCl
  59   // processes are a mix of 32-bit and 64-bit processes.
  60   uint32_t copy_bytes = std::min<uint32_t>(static_cast<uint32_t>(bytes),
  61                                            nacl::kNaClCrashInfoMaxLogSize);
  62
  63   // We copy the length of the crash data to the start of the shared memory
  64   // segment so we know how much to copy.
  65   memcpy(g_listener->crash_info_shmem_memory(), &copy_bytes, sizeof(uint32_t));
  66
  67   memcpy((char*)g_listener->crash_info_shmem_memory() + sizeof(uint32_t),
  68          data,
  69          copy_bytes);
  70 }
  71
  72 #if defined(OS_MACOSX)
  73
  74 // On Mac OS X, shm_open() works in the sandbox but does not give us
  75 // an FD that we can map as PROT_EXEC.  Rather than doing an IPC to
  76 // get an executable SHM region when CreateMemoryObject() is called,
  77 // we preallocate one on startup, since NaCl's sel_ldr only needs one
  78 // of them.  This saves a round trip.
  79
  80 base::subtle::Atomic32 g_shm_fd = -1;
  81
  82 int CreateMemoryObject(size_t size, int executable) {
  83   if (executable && size > 0) {
  84     int result_fd = base::subtle::NoBarrier_AtomicExchange(&g_shm_fd, -1);
  85     if (result_fd != -1) {
  86       // ftruncate() is disallowed by the Mac OS X sandbox and
  87       // returns EPERM.  Luckily, we can get the same effect with
  88       // lseek() + write().
  89       if (lseek(result_fd, size - 1, SEEK_SET) == -1) {
  90         LOG(ERROR) << "lseek() failed: " << errno;
  91         return -1;
  92       }
  93       if (write(result_fd, "", 1) != 1) {
  94         LOG(ERROR) << "write() failed: " << errno;
  95         return -1;
  96       }
  97       return result_fd;
  98     }
  99   }
 100   // Fall back to NaCl's default implementation.
 101   return -1;
 102 }
 103
 104 #elif defined(OS_LINUX)
 105
 106 int CreateMemoryObject(size_t size, int executable) {
 107   return content::MakeSharedMemorySegmentViaIPC(size, executable);
 108 }
 109
 110 #elif defined(OS_WIN)
 111 // We wrap the function to convert the bool return value to an int.
 112 int BrokerDuplicateHandle(NaClHandle source_handle,
 113                           uint32_t process_id,
 114                           NaClHandle* target_handle,
 115                           uint32_t desired_access,
 116                           uint32_t options) {
 117   return content::BrokerDuplicateHandle(source_handle, process_id,
 118                                         target_handle, desired_access,
 119                                         options);
 120 }
 121
 122 int AttachDebugExceptionHandler(const void* info, size_t info_size) {
 123   std::string info_string(reinterpret_cast<const char*>(info), info_size);
 124   bool result = false;
 125   if (!g_listener->Send(new NaClProcessMsg_AttachDebugExceptionHandler(
 126            info_string, &result)))
 127     return false;
 128   return result;
 129 }
 130
 131 void DebugStubPortSelectedHandler(uint16_t port) {
 132   g_listener->Send(new NaClProcessHostMsg_DebugStubPortSelected(port));
 133 }
 134
 135 #endif
 136
 137 // Creates the PPAPI IPC channel between the NaCl IRT and the host
 138 // (browser/renderer) process, and starts to listen it on the thread where
 139 // the given message_loop_proxy runs.
 140 // Also, creates and sets the corresponding NaClDesc to the given nap with
 141 // the FD #.
 142 scoped_refptr<NaClIPCAdapter> SetUpIPCAdapter(
 143     IPC::ChannelHandle* handle,
 144     scoped_refptr<base::MessageLoopProxy> message_loop_proxy,
 145     struct NaClApp* nap,
 146     int nacl_fd) {
 147   scoped_refptr<NaClIPCAdapter> ipc_adapter(
 148       new NaClIPCAdapter(*handle, message_loop_proxy.get()));
 149   ipc_adapter->ConnectChannel();
 150 #if defined(OS_POSIX)
 151   handle->socket =
 152       base::FileDescriptor(ipc_adapter->TakeClientFileDescriptor());
 153 #endif
 154
 155   // Pass a NaClDesc to the untrusted side. This will hold a ref to the
 156   // NaClIPCAdapter.
 157   NaClAppSetDesc(nap, nacl_fd, ipc_adapter->MakeNaClDesc());
 158   return ipc_adapter;
 159 }
 160
 161 }  // namespace
 162
 163 class BrowserValidationDBProxy : public NaClValidationDB {
 164  public:
 165   explicit BrowserValidationDBProxy(NaClListener* listener)
 166       : listener_(listener) {
 167   }
 168
 169   bool QueryKnownToValidate(const std::string& signature) override {
 170     // Initialize to false so that if the Send fails to write to the return
 171     // value we're safe.  For example if the message is (for some reason)
 172     // dispatched as an async message the return parameter will not be written.
 173     bool result = false;
 174     if (!listener_->Send(new NaClProcessMsg_QueryKnownToValidate(signature,
 175                                                                  &result))) {
 176       LOG(ERROR) << "Failed to query NaCl validation cache.";
 177       result = false;
 178     }
 179     return result;
 180   }
 181
 182   void SetKnownToValidate(const std::string& signature) override {
 183     // Caching is optional: NaCl will still work correctly if the IPC fails.
 184     if (!listener_->Send(new NaClProcessMsg_SetKnownToValidate(signature))) {
 185       LOG(ERROR) << "Failed to update NaCl validation cache.";
 186     }
 187   }
 188
 189  private:
 190   // The listener never dies, otherwise this might be a dangling reference.
 191   NaClListener* listener_;
 192 };
 193
 194
 195 NaClListener::NaClListener() : shutdown_event_(true, false),
 196                                io_thread_("NaCl_IOThread"),
 197 #if defined(OS_LINUX)
 198                                prereserved_sandbox_size_(0),
 199 #endif
 200 #if defined(OS_POSIX)
 201                                number_of_cores_(-1),  // unknown/error
 202 #endif
 203                                main_loop_(NULL) {
 204   io_thread_.StartWithOptions(
 205       base::Thread::Options(base::MessageLoop::TYPE_IO, 0));
 206   DCHECK(g_listener == NULL);
 207   g_listener = this;
 208 }
 209
 210 NaClListener::~NaClListener() {
 211   NOTREACHED();
 212   shutdown_event_.Signal();
 213   g_listener = NULL;
 214 }
 215
 216 bool NaClListener::Send(IPC::Message* msg) {
 217   DCHECK(main_loop_ != NULL);
 218   if (base::MessageLoop::current() == main_loop_) {
 219     // This thread owns the channel.
 220     return channel_->Send(msg);
 221   } else {
 222     // This thread does not own the channel.
 223     return filter_->Send(msg);
 224   }
 225 }
 226
 227 // The NaClProcessMsg_ResolveFileTokenAsyncReply message must be
 228 // processed in a MessageFilter so it can be handled on the IO thread.
 229 // The main thread used by NaClListener is busy in
 230 // NaClChromeMainAppStart(), so it can't be used for servicing messages.
 231 class FileTokenMessageFilter : public IPC::MessageFilter {
 232  public:
 233   bool OnMessageReceived(const IPC::Message& msg) override {
 234     bool handled = true;
 235     IPC_BEGIN_MESSAGE_MAP(FileTokenMessageFilter, msg)
 236       IPC_MESSAGE_HANDLER(NaClProcessMsg_ResolveFileTokenReply,
 237                           OnResolveFileTokenReply)
 238       IPC_MESSAGE_UNHANDLED(handled = false)
 239     IPC_END_MESSAGE_MAP()
 240     return handled;
 241   }
 242
 243   void OnResolveFileTokenReply(
 244       uint64_t token_lo,
 245       uint64_t token_hi,
 246       IPC::PlatformFileForTransit ipc_fd,
 247       base::FilePath file_path) {
 248     CHECK(g_listener);
 249     g_listener->OnFileTokenResolved(token_lo, token_hi, ipc_fd, file_path);
 250   }
 251  private:
 252   ~FileTokenMessageFilter() override {}
 253 };
 254
 255 void NaClListener::Listen() {
 256   std::string channel_name =
 257       base::CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
 258           switches::kProcessChannelID);
 259   channel_ = IPC::SyncChannel::Create(
 260       this, io_thread_.message_loop_proxy().get(), &shutdown_event_);
 261   filter_ = new IPC::SyncMessageFilter(&shutdown_event_);
 262   channel_->AddFilter(filter_.get());
 263   channel_->AddFilter(new FileTokenMessageFilter());
 264   channel_->Init(channel_name, IPC::Channel::MODE_CLIENT, true);
 265   main_loop_ = base::MessageLoop::current();
 266   main_loop_->Run();
 267 }
 268
 269 bool NaClListener::OnMessageReceived(const IPC::Message& msg) {
 270   bool handled = true;
 271   IPC_BEGIN_MESSAGE_MAP(NaClListener, msg)
 272       IPC_MESSAGE_HANDLER(NaClProcessMsg_Start, OnStart)
 273       IPC_MESSAGE_UNHANDLED(handled = false)
 274   IPC_END_MESSAGE_MAP()
 275   return handled;
 276 }
 277
 278 void NaClListener::OnStart(const nacl::NaClStartParams& params) {
 279 #if defined(OS_LINUX) || defined(OS_MACOSX)
 280   int urandom_fd = dup(base::GetUrandomFD());
 281   if (urandom_fd < 0) {
 282     LOG(ERROR) << "Failed to dup() the urandom FD";
 283     return;
 284   }
 285   NaClChromeMainSetUrandomFd(urandom_fd);
 286 #endif
 287   struct NaClApp* nap = NULL;
 288   NaClChromeMainInit();
 289
 290   crash_info_shmem_.reset(new base::SharedMemory(params.crash_info_shmem_handle,
 291                                                  false));
 292   CHECK(crash_info_shmem_->Map(nacl::kNaClCrashInfoShmemSize));
 293   NaClSetFatalErrorCallback(&FatalLogHandler);
 294
 295   nap = NaClAppCreate();
 296   if (nap == NULL) {
 297     LOG(ERROR) << "NaClAppCreate() failed";
 298     return;
 299   }
 300
 301   IPC::ChannelHandle browser_handle;
 302   IPC::ChannelHandle ppapi_renderer_handle;
 303   IPC::ChannelHandle manifest_service_handle;
 304
 305   if (params.enable_ipc_proxy) {
 306     browser_handle = IPC::Channel::GenerateVerifiedChannelID("nacl");
 307     ppapi_renderer_handle = IPC::Channel::GenerateVerifiedChannelID("nacl");
 308     manifest_service_handle = IPC::Channel::GenerateVerifiedChannelID("nacl");
 309
 310     // Create the PPAPI IPC channels between the NaCl IRT and the host
 311     // (browser/renderer) processes. The IRT uses these channels to
 312     // communicate with the host and to initialize the IPC dispatchers.
 313     SetUpIPCAdapter(&browser_handle, io_thread_.message_loop_proxy(),
 314                     nap, NACL_CHROME_DESC_BASE);
 315     SetUpIPCAdapter(&ppapi_renderer_handle, io_thread_.message_loop_proxy(),
 316                     nap, NACL_CHROME_DESC_BASE + 1);
 317
 318     scoped_refptr<NaClIPCAdapter> manifest_ipc_adapter =
 319         SetUpIPCAdapter(&manifest_service_handle,
 320                         io_thread_.message_loop_proxy(),
 321                         nap,
 322                         NACL_CHROME_DESC_BASE + 2);
 323     manifest_ipc_adapter->set_resolve_file_token_callback(
 324         base::Bind(&NaClListener::ResolveFileToken, base::Unretained(this)));
 325   }
 326
 327   trusted_listener_ = new NaClTrustedListener(
 328       IPC::Channel::GenerateVerifiedChannelID("nacl"),
 329       io_thread_.message_loop_proxy().get(),
 330       &shutdown_event_);
 331   if (!Send(new NaClProcessHostMsg_PpapiChannelsCreated(
 332           browser_handle,
 333           ppapi_renderer_handle,
 334           trusted_listener_->TakeClientChannelHandle(),
 335           manifest_service_handle)))
 336     LOG(ERROR) << "Failed to send IPC channel handle to NaClProcessHost.";
 337
 338   std::vector<nacl::FileDescriptor> handles = params.handles;
 339   struct NaClChromeMainArgs* args = NaClChromeMainArgsCreate();
 340   if (args == NULL) {
 341     LOG(ERROR) << "NaClChromeMainArgsCreate() failed";
 342     return;
 343   }
 344
 345 #if defined(OS_LINUX) || defined(OS_MACOSX)
 346   args->number_of_cores = number_of_cores_;
 347   args->create_memory_object_func = CreateMemoryObject;
 348 # if defined(OS_MACOSX)
 349   CHECK(handles.size() >= 1);
 350   g_shm_fd = nacl::ToNativeHandle(handles[handles.size() - 1]);
 351   handles.pop_back();
 352 # endif
 353 #endif
 354
 355   DCHECK(params.process_type != nacl::kUnknownNaClProcessType);
 356   CHECK(handles.size() >= 1);
 357   NaClHandle irt_handle = nacl::ToNativeHandle(handles[handles.size() - 1]);
 358   handles.pop_back();
 359
 360 #if defined(OS_WIN)
 361   args->irt_fd = _open_osfhandle(reinterpret_cast<intptr_t>(irt_handle),
 362                                  _O_RDONLY | _O_BINARY);
 363   if (args->irt_fd < 0) {
 364     LOG(ERROR) << "_open_osfhandle() failed";
 365     return;
 366   }
 367 #else
 368   args->irt_fd = irt_handle;
 369 #endif
 370
 371   if (params.validation_cache_enabled) {
 372     // SHA256 block size.
 373     CHECK_EQ(params.validation_cache_key.length(), (size_t) 64);
 374     // The cache structure is not freed and exists until the NaCl process exits.
 375     args->validation_cache = CreateValidationCache(
 376         new BrowserValidationDBProxy(this), params.validation_cache_key,
 377         params.version);
 378   }
 379
 380   CHECK(handles.size() == 1);
 381   args->imc_bootstrap_handle = nacl::ToNativeHandle(handles[0]);
 382   args->enable_debug_stub = params.enable_debug_stub;
 383
 384   // Now configure parts that depend on process type.
 385   // Start with stricter settings.
 386   args->enable_exception_handling = 0;
 387   args->enable_dyncode_syscalls = 0;
 388   // pnacl_mode=1 mostly disables things (IRT interfaces and syscalls).
 389   args->pnacl_mode = 1;
 390   // Bound the initial nexe's code segment size under PNaCl to reduce the
 391   // chance of a code spraying attack succeeding (see
 392   // https://code.google.com/p/nativeclient/issues/detail?id=3572).
 393   // We can't apply this arbitrary limit outside of PNaCl because it might
 394   // break existing NaCl apps, and this limit is only useful if the dyncode
 395   // syscalls are disabled.
 396   args->initial_nexe_max_code_bytes = 64 << 20;  // 64 MB.
 397
 398   if (params.process_type == nacl::kNativeNaClProcessType) {
 399     args->enable_exception_handling = 1;
 400     args->enable_dyncode_syscalls = 1;
 401     args->pnacl_mode = 0;
 402     args->initial_nexe_max_code_bytes = 0;
 403   } else if (params.process_type == nacl::kPNaClTranslatorProcessType) {
 404     // Transitioning the PNaCl translators to use the IRT again:
 405     // https://code.google.com/p/nativeclient/issues/detail?id=3914.
 406     // Once done, this can be removed.
 407     args->irt_load_optional = 1;
 408     args->pnacl_mode = 0;
 409   }
 410
 411 #if defined(OS_LINUX) || defined(OS_MACOSX)
 412   args->debug_stub_server_bound_socket_fd = nacl::ToNativeHandle(
 413       params.debug_stub_server_bound_socket);
 414 #endif
 415 #if defined(OS_WIN)
 416   args->broker_duplicate_handle_func = BrokerDuplicateHandle;
 417   args->attach_debug_exception_handler_func = AttachDebugExceptionHandler;
 418   args->debug_stub_server_port_selected_handler_func =
 419       DebugStubPortSelectedHandler;
 420 #endif
 421 #if defined(OS_LINUX)
 422   args->prereserved_sandbox_size = prereserved_sandbox_size_;
 423 #endif
 424
 425   base::PlatformFile nexe_file = IPC::PlatformFileForTransitToPlatformFile(
 426       params.nexe_file);
 427   std::string file_path_str = params.nexe_file_path_metadata.AsUTF8Unsafe();
 428   args->nexe_desc = NaClDescCreateWithFilePathMetadata(nexe_file,
 429                                                        file_path_str.c_str());
 430
 431 #if defined(OS_POSIX)
 432   if (params.enable_mojo) {
 433 #if !defined(OS_MACOSX)
 434     // Don't call mojo::embedder::Init on Mac; it's already been called from
 435     // ChromeMain() (see chrome/app/chrome_exe_main_mac.cc).
 436     mojo::embedder::Init(make_scoped_ptr(
 437         new mojo::embedder::SimplePlatformSupport()));
 438 #endif
 439     // InjectMojo adds a file descriptor to the process that allows Mojo calls
 440     // to use an implementation defined outside the NaCl sandbox. See
 441     // //mojo/nacl for implementation details.
 442     InjectMojo(nap);
 443   } else {
 444     // When Mojo isn't enabled, we inject a file descriptor that intentionally
 445     // fails on any imc_sendmsg() call to make debugging easier.
 446     InjectDisabledMojo(nap);
 447   }
 448 #else
 449   InjectDisabledMojo(nap);
 450 #endif
 451
 452   int exit_status;
 453   if (!NaClChromeMainStart(nap, args, &exit_status))
 454     NaClExit(1);
 455
 456   // Report the plugin's exit status if the application started successfully.
 457   trusted_listener_->Send(new NaClRendererMsg_ReportExitStatus(exit_status));
 458   NaClExit(exit_status);
 459 }
 460
 461 void NaClListener::ResolveFileToken(
 462     uint64_t token_lo,
 463     uint64_t token_hi,
 464     base::Callback<void(IPC::PlatformFileForTransit, base::FilePath)> cb) {
 465   if (!Send(new NaClProcessMsg_ResolveFileToken(token_lo, token_hi))) {
 466     cb.Run(IPC::PlatformFileForTransit(), base::FilePath());
 467     return;
 468   }
 469   resolved_cb_ = cb;
 470 }
 471
 472 void NaClListener::OnFileTokenResolved(
 473     uint64_t token_lo,
 474     uint64_t token_hi,
 475     IPC::PlatformFileForTransit ipc_fd,
 476     base::FilePath file_path) {
 477   resolved_cb_.Run(ipc_fd, file_path);
 478   resolved_cb_.Reset();
 479 }