The Tor Browser: security/sandbox/win/src/sharedmem_ipc

security/sandbox/win/src/sharedmem_ipc_server.cc@6474c204b198 (annotated)

security/sandbox/win/src/sharedmem_ipc_server.cc

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 // 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 "base/callback.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "sandbox/win/src/sharedmem_ipc_server.h"
 #include "sandbox/win/src/sharedmem_ipc_client.h"
 #include "sandbox/win/src/sandbox.h"
 #include "sandbox/win/src/sandbox_types.h"
 #include "sandbox/win/src/crosscall_params.h"
 #include "sandbox/win/src/crosscall_server.h"
 namespace sandbox {
 SharedMemIPCServer::SharedMemIPCServer(HANDLE target_process,
                                        DWORD target_process_id,
                                        HANDLE target_job,
                                        ThreadProvider* thread_provider,
                                        Dispatcher* dispatcher)
     : client_control_(NULL),
       thread_provider_(thread_provider),
       target_process_(target_process),
       target_process_id_(target_process_id),
       target_job_object_(target_job),
       call_dispatcher_(dispatcher) {
 }
 SharedMemIPCServer::~SharedMemIPCServer() {
   // Free the wait handles associated with the thread pool.
   if (!thread_provider_->UnRegisterWaits(this)) {
     // Better to leak than to crash.
     return;
   }
   // Free the IPC signal events.
   ServerContexts::iterator it;
   for (it = server_contexts_.begin(); it != server_contexts_.end(); ++it) {
     ServerControl* context = (*it);
     ::CloseHandle(context->ping_event);
     ::CloseHandle(context->pong_event);
     delete context;
   }
 }
 bool SharedMemIPCServer::Init(void* shared_mem, uint32 shared_size,
                               uint32 channel_size) {
   // The shared memory needs to be at least as big as a channel.
   if (shared_size < channel_size) {
     return false;
   }
   // The channel size should be aligned.
   if (0 != (channel_size % 32)) {
     return false;
   }
   // Calculate how many channels we can fit in the shared memory.
   shared_size -= offsetof(IPCControl, channels);
   size_t channel_count = shared_size / (sizeof(ChannelControl) + channel_size);
   // If we cannot fit even one channel we bail out.
   if (0 == channel_count) {
     return false;
   }
   // Calculate the start of the first channel.
   size_t base_start = (sizeof(ChannelControl)* channel_count) +
                        offsetof(IPCControl, channels);
   client_control_ = reinterpret_cast<IPCControl*>(shared_mem);
   client_control_->channels_count = 0;
   // This is the initialization that we do per-channel. Basically:
   // 1) make two events (ping & pong)
   // 2) create handles to the events for the client and the server.
   // 3) initialize the channel (client_context) with the state.
   // 4) initialize the server side of the channel (service_context).
   // 5) call the thread provider RegisterWait to register the ping events.
   for (size_t ix = 0; ix != channel_count; ++ix) {
     ChannelControl* client_context = &client_control_->channels[ix];
     ServerControl* service_context = new ServerControl;
     server_contexts_.push_back(service_context);
     if (!MakeEvents(&service_context->ping_event,
                     &service_context->pong_event,
                     &client_context->ping_event,
                     &client_context->pong_event)) {
       return false;
     }
     client_context->channel_base = base_start;
     client_context->state = kFreeChannel;
     // Note that some of these values are available as members of this
     // object but we put them again into the service_context because we
     // will be called on a static method (ThreadPingEventReady)
     service_context->shared_base = reinterpret_cast<char*>(shared_mem);
     service_context->channel_size = channel_size;
     service_context->channel = client_context;
     service_context->channel_buffer = service_context->shared_base +
                                       client_context->channel_base;
     service_context->dispatcher = call_dispatcher_;
     service_context->target_info.process = target_process_;
     service_context->target_info.process_id = target_process_id_;
     service_context->target_info.job_object = target_job_object_;
     // Advance to the next channel.
     base_start += channel_size;
     // Register the ping event with the threadpool.
     thread_provider_->RegisterWait(this, service_context->ping_event,
                                    ThreadPingEventReady, service_context);
   }
   // We create a mutex that the server locks. If the server dies unexpectedly,
   // the thread that owns it will fail to release the lock and windows will
   // report to the target (when it tries to acquire it) that the wait was
   // abandoned. Note: We purposely leak the local handle because we want it to
   // be closed by Windows itself so it is properly marked as abandoned if the
   // server dies.
   if (!::DuplicateHandle(::GetCurrentProcess(),
                          ::CreateMutexW(NULL, TRUE, NULL),
                          target_process_, &client_control_->server_alive,
                          SYNCHRONIZE | EVENT_MODIFY_STATE, FALSE, 0)) {
     return false;
   }
   // This last setting indicates to the client all is setup.
   client_control_->channels_count = channel_count;
   return true;
 }
 // Releases memory allocated for IPC arguments, if needed.
 void ReleaseArgs(const IPCParams* ipc_params, void* args[kMaxIpcParams]) {
   for (size_t i = 0; i < kMaxIpcParams; i++) {
     switch (ipc_params->args[i]) {
       case WCHAR_TYPE: {
         delete reinterpret_cast<std::wstring*>(args[i]);
         args[i] = NULL;
         break;
       }
       case INOUTPTR_TYPE: {
         delete reinterpret_cast<CountedBuffer*>(args[i]);
         args[i] = NULL;
         break;
       }
       default: break;
     }
   }
 }
 // Fills up the list of arguments (args and ipc_params) for an IPC call.
 bool GetArgs(CrossCallParamsEx* params, IPCParams* ipc_params,
              void* args[kMaxIpcParams]) {
   if (kMaxIpcParams < params->GetParamsCount())
     return false;
   for (uint32 i = 0; i < params->GetParamsCount(); i++) {
     uint32 size;
     ArgType type;
     args[i] = params->GetRawParameter(i, &size, &type);
     if (args[i]) {
       ipc_params->args[i] = type;
       switch (type) {
         case WCHAR_TYPE: {
           scoped_ptr<std::wstring> data(new std::wstring);
           if (!params->GetParameterStr(i, data.get())) {
             args[i] = 0;
             ReleaseArgs(ipc_params, args);
             return false;
           }
           args[i] = data.release();
           break;
         }
         case ULONG_TYPE: {
           uint32 data;
           if (!params->GetParameter32(i, &data)) {
             ReleaseArgs(ipc_params, args);
             return false;
           }
           IPCInt ipc_int(data);
           args[i] = ipc_int.AsVoidPtr();
           break;
         }
         case VOIDPTR_TYPE : {
           void* data;
           if (!params->GetParameterVoidPtr(i, &data)) {
             ReleaseArgs(ipc_params, args);
             return false;
           }
           args[i] = data;
           break;
         }
         case INOUTPTR_TYPE: {
           if (!args[i]) {
             ReleaseArgs(ipc_params, args);
             return false;
           }
           CountedBuffer* buffer = new CountedBuffer(args[i] , size);
           args[i] = buffer;
           break;
         }
         default: break;
       }
     }
   }
   return true;
 }
 bool SharedMemIPCServer::InvokeCallback(const ServerControl* service_context,
                                         void* ipc_buffer,
                                         CrossCallReturn* call_result) {
   // Set the default error code;
   SetCallError(SBOX_ERROR_INVALID_IPC, call_result);
   uint32 output_size = 0;
   // Parse, verify and copy the message. The handler operates on a copy
   // of the message so the client cannot play dirty tricks by changing the
   // data in the channel while the IPC is being processed.
   scoped_ptr<CrossCallParamsEx> params(
       CrossCallParamsEx::CreateFromBuffer(ipc_buffer,
                                           service_context->channel_size,
                                           &output_size));
   if (!params.get())
     return false;
   uint32 tag = params->GetTag();
   COMPILE_ASSERT(0 == INVALID_TYPE, Incorrect_type_enum);
   IPCParams ipc_params = {0};
   ipc_params.ipc_tag = tag;
   void* args[kMaxIpcParams];
   if (!GetArgs(params.get(), &ipc_params, args))
     return false;
   IPCInfo ipc_info = {0};
   ipc_info.ipc_tag = tag;
   ipc_info.client_info = &service_context->target_info;
   Dispatcher* dispatcher = service_context->dispatcher;
   DCHECK(dispatcher);
   bool error = true;
   Dispatcher* handler = NULL;
   Dispatcher::CallbackGeneric callback_generic;
   handler = dispatcher->OnMessageReady(&ipc_params, &callback_generic);
   if (handler) {
     switch (params->GetParamsCount()) {
       case 0: {
         // Ask the IPC dispatcher if she can service this IPC.
         Dispatcher::Callback0 callback =
             reinterpret_cast<Dispatcher::Callback0>(callback_generic);
         if (!(handler->*callback)(&ipc_info))
           break;
         error = false;
         break;
       }
       case 1: {
         Dispatcher::Callback1 callback =
             reinterpret_cast<Dispatcher::Callback1>(callback_generic);
         if (!(handler->*callback)(&ipc_info, args[0]))
           break;
         error = false;
         break;
       }
       case 2: {
         Dispatcher::Callback2 callback =
             reinterpret_cast<Dispatcher::Callback2>(callback_generic);
         if (!(handler->*callback)(&ipc_info, args[0], args[1]))
           break;
         error = false;
         break;
       }
       case 3: {
         Dispatcher::Callback3 callback =
             reinterpret_cast<Dispatcher::Callback3>(callback_generic);
         if (!(handler->*callback)(&ipc_info, args[0], args[1], args[2]))
           break;
         error = false;
         break;
       }
       case 4: {
         Dispatcher::Callback4 callback =
             reinterpret_cast<Dispatcher::Callback4>(callback_generic);
         if (!(handler->*callback)(&ipc_info, args[0], args[1], args[2],
                                   args[3]))
           break;
         error = false;
         break;
       }
       case 5: {
         Dispatcher::Callback5 callback =
             reinterpret_cast<Dispatcher::Callback5>(callback_generic);
         if (!(handler->*callback)(&ipc_info, args[0], args[1], args[2], args[3],
                                   args[4]))
           break;
         error = false;
         break;
       }
       case 6: {
         Dispatcher::Callback6 callback =
             reinterpret_cast<Dispatcher::Callback6>(callback_generic);
         if (!(handler->*callback)(&ipc_info, args[0], args[1], args[2], args[3],
                                   args[4], args[5]))
           break;
         error = false;
         break;
       }
       case 7: {
         Dispatcher::Callback7 callback =
             reinterpret_cast<Dispatcher::Callback7>(callback_generic);
         if (!(handler->*callback)(&ipc_info, args[0], args[1], args[2], args[3],
                                   args[4], args[5], args[6]))
           break;
         error = false;
         break;
       }
       case 8: {
         Dispatcher::Callback8 callback =
             reinterpret_cast<Dispatcher::Callback8>(callback_generic);
         if (!(handler->*callback)(&ipc_info, args[0], args[1], args[2], args[3],
                                   args[4], args[5], args[6], args[7]))
           break;
         error = false;
         break;
       }
       case 9: {
         Dispatcher::Callback9 callback =
             reinterpret_cast<Dispatcher::Callback9>(callback_generic);
         if (!(handler->*callback)(&ipc_info, args[0], args[1], args[2], args[3],
                                   args[4], args[5], args[6], args[7], args[8]))
           break;
         error = false;
         break;
       }
       default:  {
         NOTREACHED();
         break;
       }
     }
   }
   if (error) {
     if (handler)
       SetCallError(SBOX_ERROR_FAILED_IPC, call_result);
   } else {
     memcpy(call_result, &ipc_info.return_info, sizeof(*call_result));
     SetCallSuccess(call_result);
     if (params->IsInOut()) {
       // Maybe the params got changed by the broker. We need to upadte the
       // memory section.
       memcpy(ipc_buffer, params.get(), output_size);
     }
   }
   ReleaseArgs(&ipc_params, args);
   return !error;
 }
 // This function gets called by a thread from the thread pool when a
 // ping event fires. The context is the same as passed in the RegisterWait()
 // call above.
 void __stdcall SharedMemIPCServer::ThreadPingEventReady(void* context,
                                                         unsigned char) {
   if (NULL == context) {
     DCHECK(false);
     return;
   }
   ServerControl* service_context = reinterpret_cast<ServerControl*>(context);
   // Since the event fired, the channel *must* be busy. Change to kAckChannel
   // while we service it.
   LONG last_state =
     ::InterlockedCompareExchange(&service_context->channel->state,
                                  kAckChannel, kBusyChannel);
   if (kBusyChannel != last_state) {
     DCHECK(false);
     return;
   }
   // Prepare the result structure. At this point we will return some result
   // even if the IPC is invalid, malformed or has no handler.
   CrossCallReturn call_result = {0};
   void* buffer = service_context->channel_buffer;
   InvokeCallback(service_context, buffer, &call_result);
   // Copy the answer back into the channel and signal the pong event. This
   // should wake up the client so he can finish the the ipc cycle.
   CrossCallParams* call_params = reinterpret_cast<CrossCallParams*>(buffer);
   memcpy(call_params->GetCallReturn(), &call_result, sizeof(call_result));
   ::InterlockedExchange(&service_context->channel->state, kAckChannel);
   ::SetEvent(service_context->pong_event);
 }
 bool SharedMemIPCServer::MakeEvents(HANDLE* server_ping, HANDLE* server_pong,
                                     HANDLE* client_ping, HANDLE* client_pong) {
   // Note that the IPC client has no right to delete the events. That would
   // cause problems. The server *owns* the events.
   const DWORD kDesiredAccess = SYNCHRONIZE | EVENT_MODIFY_STATE;
   // The events are auto reset, and start not signaled.
   *server_ping = ::CreateEventW(NULL, FALSE, FALSE, NULL);
   if (!::DuplicateHandle(::GetCurrentProcess(), *server_ping, target_process_,
                          client_ping, kDesiredAccess, FALSE, 0)) {
     return false;
   }
   *server_pong = ::CreateEventW(NULL, FALSE, FALSE, NULL);
   if (!::DuplicateHandle(::GetCurrentProcess(), *server_pong, target_process_,
                          client_pong, kDesiredAccess, FALSE, 0)) {
     return false;
   }
   return true;
 }
 }  // namespace sandbox

The Tor Browser / annotate

security/sandbox/win/src/sharedmem_ipc_server.cc@6474c204b198 (annotated)

security/sandbox/win/src/sharedmem_ipc_server.cc