sandbox/win/src/Wow64.cc

   1 // Copyright (c) 2012 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 "sandbox/win/src/wow64.h"
   6
   7 #include <sstream>
   8
   9 #include "base/logging.h"
  10 #include "base/memory/scoped_ptr.h"
  11 #include "base/win/scoped_process_information.h"
  12 #include "base/win/windows_version.h"
  13 #include "sandbox/win/src/target_process.h"
  14
  15 namespace {
  16
  17 // Holds the information needed for the interception of NtMapViewOfSection on
  18 // 64 bits.
  19 // Warning: do not modify this definition without changing also the code on the
  20 // 64 bit helper process.
  21 struct PatchInfo32 {
  22   HANDLE dll_load;  // Event to signal the broker.
  23   ULONG pad1;
  24   HANDLE continue_load;  // Event to wait for the broker.
  25   ULONG pad2;
  26   HANDLE section;  // First argument of the call.
  27   ULONG pad3;
  28   void* orig_MapViewOfSection;
  29   ULONG original_high;
  30   void* signal_and_wait;
  31   ULONG pad4;
  32   void* patch_location;
  33   ULONG patch_high;
  34 };
  35
  36 // Size of the 64 bit service entry.
  37 const SIZE_T kServiceEntry64Size = 0x10;
  38
  39 // Removes the interception of ntdll64.
  40 bool Restore64Code(HANDLE child, PatchInfo32* patch_info) {
  41   PatchInfo32 local_patch_info;
  42   SIZE_T actual;
  43   if (!::ReadProcessMemory(child, patch_info, &local_patch_info,
  44                            sizeof(local_patch_info), &actual))
  45     return false;
  46   if (sizeof(local_patch_info) != actual)
  47     return false;
  48
  49   if (local_patch_info.original_high)
  50     return false;
  51   if (local_patch_info.patch_high)
  52     return false;
  53
  54   char buffer[kServiceEntry64Size];
  55
  56   if (!::ReadProcessMemory(child, local_patch_info.orig_MapViewOfSection,
  57                            &buffer, kServiceEntry64Size, &actual))
  58     return false;
  59   if (kServiceEntry64Size != actual)
  60     return false;
  61
  62   if (!::WriteProcessMemory(child, local_patch_info.patch_location, &buffer,
  63                             kServiceEntry64Size, &actual))
  64     return false;
  65   if (kServiceEntry64Size != actual)
  66     return false;
  67   return true;
  68 }
  69
  70 typedef BOOL (WINAPI* IsWow64ProcessFunction)(HANDLE process, BOOL* wow64);
  71
  72 }  // namespace
  73
  74 namespace sandbox {
  75
  76 Wow64::~Wow64() {
  77   if (dll_load_)
  78     ::CloseHandle(dll_load_);
  79
  80   if (continue_load_)
  81     ::CloseHandle(continue_load_);
  82 }
  83
  84 // The basic idea is to allocate one page of memory on the child, and initialize
  85 // the first part of it with our version of PatchInfo32. Then launch the helper
  86 // process passing it that address on the child. The helper process will patch
  87 // the 64 bit version of NtMapViewOfFile, and the interception will signal the
  88 // first event on the buffer. We'll be waiting on that event and after the 32
  89 // bit version of ntdll is loaded, we'll remove the interception and return to
  90 // our caller.
  91 bool Wow64::WaitForNtdll() {
  92   if (base::win::OSInfo::GetInstance()->wow64_status() !=
  93       base::win::OSInfo::WOW64_ENABLED)
  94     return true;
  95
  96   const size_t page_size = 4096;
  97
  98   // Create some default manual reset un-named events, not signaled.
  99   dll_load_ = ::CreateEvent(NULL, TRUE, FALSE, NULL);
 100   continue_load_ = ::CreateEvent(NULL, TRUE, FALSE, NULL);
 101   HANDLE current_process = ::GetCurrentProcess();
 102   HANDLE remote_load, remote_continue;
 103   DWORD access = EVENT_MODIFY_STATE | SYNCHRONIZE;
 104   if (!::DuplicateHandle(current_process, dll_load_, child_->Process(),
 105                          &remote_load, access, FALSE, 0))
 106     return false;
 107   if (!::DuplicateHandle(current_process, continue_load_, child_->Process(),
 108                          &remote_continue, access, FALSE, 0))
 109     return false;
 110
 111   void* buffer = ::VirtualAllocEx(child_->Process(), NULL, page_size,
 112                                   MEM_COMMIT, PAGE_EXECUTE_READWRITE);
 113   DCHECK(buffer);
 114   if (!buffer)
 115     return false;
 116
 117   PatchInfo32* patch_info = reinterpret_cast<PatchInfo32*>(buffer);
 118   PatchInfo32 local_patch_info = {0};
 119   local_patch_info.dll_load = remote_load;
 120   local_patch_info.continue_load = remote_continue;
 121   SIZE_T written;
 122   if (!::WriteProcessMemory(child_->Process(), patch_info, &local_patch_info,
 123                             offsetof(PatchInfo32, section), &written))
 124     return false;
 125   if (offsetof(PatchInfo32, section) != written)
 126     return false;
 127
 128   if (!RunWowHelper(buffer))
 129     return false;
 130
 131   // The child is intercepted on 64 bit, go on and wait for our event.
 132   if (!DllMapped())
 133     return false;
 134
 135   // The 32 bit version is available, cleanup the child.
 136   return Restore64Code(child_->Process(), patch_info);
 137 }
 138
 139 bool Wow64::RunWowHelper(void* buffer) {
 140   static_assert(sizeof(buffer) <= sizeof(DWORD), "unsupported 64 bits");
 141
 142   // Get the path to the helper (beside the exe).
 143   wchar_t prog_name[MAX_PATH];
 144   GetModuleFileNameW(NULL, prog_name, MAX_PATH);
 145   base::string16 path(prog_name);
 146   size_t name_pos = path.find_last_of(L"\\");
 147   if (base::string16::npos == name_pos)
 148     return false;
 149   path.resize(name_pos + 1);
 150
 151   std::basic_stringstream<base::char16> command;
 152   command << std::hex << std::showbase << L"\"" << path <<
 153                L"wow_helper.exe\" " << child_->ProcessId() << " " <<
 154                bit_cast<ULONG>(buffer);
 155
 156   scoped_ptr<wchar_t, base::FreeDeleter>
 157       writable_command(_wcsdup(command.str().c_str()));
 158
 159   STARTUPINFO startup_info = {0};
 160   startup_info.cb = sizeof(startup_info);
 161   PROCESS_INFORMATION temp_process_info = {};
 162   if (!::CreateProcess(NULL, writable_command.get(), NULL, NULL, FALSE, 0, NULL,
 163                        NULL, &startup_info, &temp_process_info))
 164     return false;
 165   base::win::ScopedProcessInformation process_info(temp_process_info);
 166
 167   DWORD reason = ::WaitForSingleObject(process_info.process_handle(), INFINITE);
 168
 169   DWORD code;
 170   bool ok =
 171       ::GetExitCodeProcess(process_info.process_handle(), &code) ? true : false;
 172
 173   if (WAIT_TIMEOUT == reason)
 174     return false;
 175
 176   return ok && (0 == code);
 177 }
 178
 179 // First we must wake up the child, then wait for dll loads on the child until
 180 // the one we care is loaded; at that point we must suspend the child again.
 181 bool Wow64::DllMapped() {
 182   if (1 != ::ResumeThread(child_->MainThread())) {
 183     NOTREACHED();
 184     return false;
 185   }
 186
 187   for (;;) {
 188     DWORD reason = ::WaitForSingleObject(dll_load_, INFINITE);
 189     if (WAIT_TIMEOUT == reason || WAIT_ABANDONED == reason)
 190       return false;
 191
 192     if (!::ResetEvent(dll_load_))
 193       return false;
 194
 195     bool found = NtdllPresent();
 196     if (found) {
 197       if (::SuspendThread(child_->MainThread()))
 198         return false;
 199     }
 200
 201     if (!::SetEvent(continue_load_))
 202       return false;
 203
 204     if (found)
 205       return true;
 206   }
 207 }
 208
 209 bool Wow64::NtdllPresent() {
 210   const size_t kBufferSize = 512;
 211   char buffer[kBufferSize];
 212   SIZE_T read;
 213   if (!::ReadProcessMemory(child_->Process(), ntdll_, &buffer, kBufferSize,
 214                            &read))
 215     return false;
 216   if (kBufferSize != read)
 217     return false;
 218   return true;
 219 }
 220
 221 }  // namespace sandbox