chrome_elf/blacklist/blacklist.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 "chrome_elf/blacklist/blacklist.h"
   6
   7 #include <assert.h>
   8 #include <string.h>
   9
  10 #include <vector>
  11
  12 #include "base/basictypes.h"
  13 #include "chrome_elf/blacklist/blacklist_interceptions.h"
  14 #include "chrome_elf/chrome_elf_constants.h"
  15 #include "chrome_elf/chrome_elf_util.h"
  16 #include "chrome_elf/thunk_getter.h"
  17 #include "sandbox/win/src/interception_internal.h"
  18 #include "sandbox/win/src/internal_types.h"
  19 #include "sandbox/win/src/service_resolver.h"
  20
  21 // http://blogs.msdn.com/oldnewthing/archive/2004/10/25/247180.aspx
  22 extern "C" IMAGE_DOS_HEADER __ImageBase;
  23
  24 namespace blacklist{
  25
  26 // The DLLs listed here are known (or under strong suspicion) of causing crashes
  27 // when they are loaded in the browser. DLLs should only be added to this list
  28 // if there is nothing else Chrome can do to prevent those crashes.
  29 // For more information about how this list is generated, and how to get off
  30 // of it, see:
  31 // https://sites.google.com/a/chromium.org/dev/Home/third-party-developers
  32 // NOTE: Please remember to update the DllHash enum in histograms.xml when
  33 //       adding a new value to the blacklist.
  34 const wchar_t* g_troublesome_dlls[kTroublesomeDllsMaxCount] = {
  35   L"activedetect32.dll",                // Lenovo One Key Theater.
  36                                         // See crbug.com/379218.
  37   L"activedetect64.dll",                // Lenovo One Key Theater.
  38   L"bitguard.dll",                      // Unknown (suspected malware).
  39   L"bsvc.dll",                          // Unknown (suspected adware).
  40   L"chrmxtn.dll",                       // Unknown (keystroke logger).
  41   L"cplushook.dll",                     // Unknown (suspected malware).
  42   L"crdli.dll",                         // Linkury Inc.
  43   L"crdli64.dll",                       // Linkury Inc.
  44   L"datamngr.dll",                      // Unknown (suspected adware).
  45   L"explorerex.dll",                    // Unknown (suspected adware).
  46   L"hk.dll",                            // Unknown (keystroke logger).
  47   L"libapi2hook.dll",                   // V-Bates.
  48   L"libinject.dll",                     // V-Bates.
  49   L"libinject2.dll",                    // V-Bates.
  50   L"libredir2.dll",                     // V-Bates.
  51   L"libsvn_tsvn32.dll",                 // TortoiseSVN.
  52   L"libwinhook.dll",                    // V-Bates.
  53   L"lmrn.dll",                          // Unknown.
  54   L"minisp.dll",                        // Unknown (suspected malware).
  55   L"minisp32.dll",                      // Unknown (suspected malware).
  56   L"safetynut.dll",                     // Unknown (suspected adware).
  57   L"smdmf.dll",                         // Unknown (suspected adware).
  58   L"systemk.dll",                       // Unknown (suspected adware).
  59   L"vntsrv.dll",                        // Virtual New Tab by APN LLC.
  60   L"wajam_goblin_64.dll",               // Wajam Internet Technologies.
  61   L"wajam_goblin.dll",                  // Wajam Internet Technologies.
  62   L"windowsapihookdll32.dll",           // Lenovo One Key Theater.
  63                                         // See crbug.com/379218.
  64   L"windowsapihookdll64.dll",           // Lenovo One Key Theater.
  65   L"virtualcamera.ax",                  // %PROGRAMFILES%\ASUS\VirtualCamera.
  66                                         // See crbug.com/422522.
  67   L"ycwebcamerasource.ax",              // CyberLink Youcam, crbug.com/424159
  68   // Keep this null pointer here to mark the end of the list.
  69   NULL,
  70 };
  71
  72 bool g_blocked_dlls[kTroublesomeDllsMaxCount] = {};
  73 int g_num_blocked_dlls = 0;
  74
  75 }  // namespace blacklist
  76
  77 // Allocate storage for thunks in a page of this module to save on doing
  78 // an extra allocation at run time.
  79 #pragma section(".crthunk",read,execute)
  80 __declspec(allocate(".crthunk")) sandbox::ThunkData g_thunk_storage;
  81
  82 namespace {
  83
  84 // Record if the blacklist was successfully initialized so processes can easily
  85 // determine if the blacklist is enabled for them.
  86 bool g_blacklist_initialized = false;
  87
  88 // Helper to set DWORD registry values.
  89 DWORD SetDWValue(HKEY* key, const wchar_t* property, DWORD value) {
  90   return ::RegSetValueEx(*key,
  91                          property,
  92                          0,
  93                          REG_DWORD,
  94                          reinterpret_cast<LPBYTE>(&value),
  95                          sizeof(value));
  96 }
  97
  98 bool GenerateStateFromBeaconAndAttemptCount(HKEY* key, DWORD blacklist_state) {
  99   LONG result = 0;
 100   if (blacklist_state == blacklist::BLACKLIST_ENABLED) {
 101     // If the blacklist succeeded on the previous run reset the failure
 102     // counter.
 103     return (SetDWValue(key,
 104                        blacklist::kBeaconAttemptCount,
 105                        static_cast<DWORD>(0)) == ERROR_SUCCESS);
 106   } else {
 107     // Some part of the blacklist setup failed last time.  If this has occured
 108     // blacklist::kBeaconMaxAttempts times in a row we switch the state to
 109     // failed and skip setting up the blacklist.
 110     DWORD attempt_count = 0;
 111     DWORD attempt_count_size = sizeof(attempt_count);
 112     result = ::RegQueryValueEx(*key,
 113                                blacklist::kBeaconAttemptCount,
 114                                0,
 115                                NULL,
 116                                reinterpret_cast<LPBYTE>(&attempt_count),
 117                                &attempt_count_size);
 118
 119     if (result == ERROR_FILE_NOT_FOUND)
 120       attempt_count = 0;
 121     else if (result != ERROR_SUCCESS)
 122       return false;
 123
 124     ++attempt_count;
 125     SetDWValue(key, blacklist::kBeaconAttemptCount, attempt_count);
 126
 127     if (attempt_count >= blacklist::kBeaconMaxAttempts) {
 128       blacklist_state = blacklist::BLACKLIST_SETUP_FAILED;
 129       SetDWValue(key, blacklist::kBeaconState, blacklist_state);
 130     }
 131
 132     return false;
 133   }
 134 }
 135
 136 }  // namespace
 137
 138 namespace blacklist {
 139
 140 #if defined(_WIN64)
 141   // Allocate storage for the pointer to the old NtMapViewOfSectionFunction.
 142 #pragma section(".oldntmap",write,read)
 143   __declspec(allocate(".oldntmap"))
 144     NtMapViewOfSectionFunction g_nt_map_view_of_section_func = NULL;
 145 #endif
 146
 147 bool LeaveSetupBeacon() {
 148   HKEY key = NULL;
 149   DWORD disposition = 0;
 150   LONG result = ::RegCreateKeyEx(HKEY_CURRENT_USER,
 151                                  kRegistryBeaconPath,
 152                                  0,
 153                                  NULL,
 154                                  REG_OPTION_NON_VOLATILE,
 155                                  KEY_QUERY_VALUE | KEY_SET_VALUE,
 156                                  NULL,
 157                                  &key,
 158                                  &disposition);
 159   if (result != ERROR_SUCCESS)
 160     return false;
 161
 162   // Retrieve the current blacklist state.
 163   DWORD blacklist_state = BLACKLIST_STATE_MAX;
 164   DWORD blacklist_state_size = sizeof(blacklist_state);
 165   DWORD type = 0;
 166   result = ::RegQueryValueEx(key,
 167                              kBeaconState,
 168                              0,
 169                              &type,
 170                              reinterpret_cast<LPBYTE>(&blacklist_state),
 171                              &blacklist_state_size);
 172
 173   if (result != ERROR_SUCCESS || blacklist_state == BLACKLIST_DISABLED ||
 174       type != REG_DWORD) {
 175     ::RegCloseKey(key);
 176     return false;
 177   }
 178
 179   if (!GenerateStateFromBeaconAndAttemptCount(&key, blacklist_state)) {
 180     ::RegCloseKey(key);
 181     return false;
 182   }
 183
 184   result = SetDWValue(&key, kBeaconState, BLACKLIST_SETUP_RUNNING);
 185   ::RegCloseKey(key);
 186
 187   return (result == ERROR_SUCCESS);
 188 }
 189
 190 bool ResetBeacon() {
 191   HKEY key = NULL;
 192   DWORD disposition = 0;
 193   LONG result = ::RegCreateKeyEx(HKEY_CURRENT_USER,
 194                                  kRegistryBeaconPath,
 195                                  0,
 196                                  NULL,
 197                                  REG_OPTION_NON_VOLATILE,
 198                                  KEY_QUERY_VALUE | KEY_SET_VALUE,
 199                                  NULL,
 200                                  &key,
 201                                  &disposition);
 202   if (result != ERROR_SUCCESS)
 203     return false;
 204
 205   DWORD blacklist_state = BLACKLIST_STATE_MAX;
 206   DWORD blacklist_state_size = sizeof(blacklist_state);
 207   DWORD type = 0;
 208   result = ::RegQueryValueEx(key,
 209                              kBeaconState,
 210                              0,
 211                              &type,
 212                              reinterpret_cast<LPBYTE>(&blacklist_state),
 213                              &blacklist_state_size);
 214
 215   if (result != ERROR_SUCCESS || type != REG_DWORD) {
 216     ::RegCloseKey(key);
 217     return false;
 218   }
 219
 220   // Reaching this point with the setup running state means the setup did not
 221   // crash, so we reset to enabled.  Any other state indicates that setup was
 222   // skipped; in that case we leave the state alone for later recording.
 223   if (blacklist_state == BLACKLIST_SETUP_RUNNING)
 224     result = SetDWValue(&key, kBeaconState, BLACKLIST_ENABLED);
 225
 226   ::RegCloseKey(key);
 227   return (result == ERROR_SUCCESS);
 228 }
 229
 230 int BlacklistSize() {
 231   int size = -1;
 232   while (blacklist::g_troublesome_dlls[++size] != NULL) {}
 233
 234   return size;
 235 }
 236
 237 bool IsBlacklistInitialized() {
 238   return g_blacklist_initialized;
 239 }
 240
 241 int GetBlacklistIndex(const wchar_t* dll_name) {
 242   for (int i = 0; i < kTroublesomeDllsMaxCount && g_troublesome_dlls[i]; ++i) {
 243     if (_wcsicmp(dll_name, g_troublesome_dlls[i]) == 0)
 244       return i;
 245   }
 246   return -1;
 247 }
 248
 249 bool AddDllToBlacklist(const wchar_t* dll_name) {
 250   int blacklist_size = BlacklistSize();
 251   // We need to leave one space at the end for the null pointer.
 252   if (blacklist_size + 1 >= kTroublesomeDllsMaxCount)
 253     return false;
 254   for (int i = 0; i < blacklist_size; ++i) {
 255     if (!_wcsicmp(g_troublesome_dlls[i], dll_name))
 256       return true;
 257   }
 258
 259   // Copy string to blacklist.
 260   wchar_t* str_buffer = new wchar_t[wcslen(dll_name) + 1];
 261   wcscpy(str_buffer, dll_name);
 262
 263   g_troublesome_dlls[blacklist_size] = str_buffer;
 264   g_blocked_dlls[blacklist_size] = false;
 265   return true;
 266 }
 267
 268 bool RemoveDllFromBlacklist(const wchar_t* dll_name) {
 269   int blacklist_size = BlacklistSize();
 270   for (int i = 0; i < blacklist_size; ++i) {
 271     if (!_wcsicmp(g_troublesome_dlls[i], dll_name)) {
 272       // Found the thing to remove. Delete it then replace it with the last
 273       // element.
 274       delete[] g_troublesome_dlls[i];
 275       g_troublesome_dlls[i] = g_troublesome_dlls[blacklist_size - 1];
 276       g_troublesome_dlls[blacklist_size - 1] = NULL;
 277
 278       // Also update the stats recording if we have blocked this dll or not.
 279       if (g_blocked_dlls[i])
 280         --g_num_blocked_dlls;
 281       g_blocked_dlls[i] = g_blocked_dlls[blacklist_size - 1];
 282       return true;
 283     }
 284   }
 285   return false;
 286 }
 287
 288 // TODO(csharp): Maybe store these values in the registry so we can
 289 // still report them if Chrome crashes early.
 290 void SuccessfullyBlocked(const wchar_t** blocked_dlls, int* size) {
 291   if (size == NULL)
 292     return;
 293
 294   // If the array isn't valid or big enough, just report the size it needs to
 295   // be and return.
 296   if (blocked_dlls == NULL && *size < g_num_blocked_dlls) {
 297     *size = g_num_blocked_dlls;
 298     return;
 299   }
 300
 301   *size = g_num_blocked_dlls;
 302
 303   int strings_to_fill = 0;
 304   for (int i = 0; strings_to_fill < g_num_blocked_dlls && g_troublesome_dlls[i];
 305        ++i) {
 306     if (g_blocked_dlls[i]) {
 307       blocked_dlls[strings_to_fill] = g_troublesome_dlls[i];
 308       ++strings_to_fill;
 309     }
 310   }
 311 }
 312
 313 void BlockedDll(size_t blocked_index) {
 314   assert(blocked_index < kTroublesomeDllsMaxCount);
 315
 316   if (!g_blocked_dlls[blocked_index] &&
 317       blocked_index < kTroublesomeDllsMaxCount) {
 318     ++g_num_blocked_dlls;
 319     g_blocked_dlls[blocked_index] = true;
 320   }
 321 }
 322
 323 bool Initialize(bool force) {
 324   // Check to see that we found the functions we need in ntdll.
 325   if (!InitializeInterceptImports())
 326     return false;
 327
 328   // Check to see if this is a non-browser process, abort if so.
 329   if (IsNonBrowserProcess())
 330     return false;
 331
 332   // Check to see if the blacklist beacon is still set to running (indicating a
 333   // failure) or disabled, and abort if so.
 334   if (!force && !LeaveSetupBeacon())
 335     return false;
 336
 337   // It is possible for other dlls to have already patched code by now and
 338   // attempting to patch their code might result in crashes.
 339   const bool kRelaxed = false;
 340
 341   // Create a thunk via the appropriate ServiceResolver instance.
 342   sandbox::ServiceResolverThunk* thunk = GetThunk(kRelaxed);
 343
 344   // Don't try blacklisting on unsupported OS versions.
 345   if (!thunk)
 346     return false;
 347
 348   BYTE* thunk_storage = reinterpret_cast<BYTE*>(&g_thunk_storage);
 349
 350   // Mark the thunk storage as readable and writeable, since we
 351   // ready to write to it.
 352   DWORD old_protect = 0;
 353   if (!VirtualProtect(&g_thunk_storage,
 354                       sizeof(g_thunk_storage),
 355                       PAGE_EXECUTE_READWRITE,
 356                       &old_protect)) {
 357     return false;
 358   }
 359
 360   thunk->AllowLocalPatches();
 361
 362   // We declare this early so it can be used in the 64-bit block below and
 363   // still work on 32-bit build when referenced at the end of the function.
 364   BOOL page_executable = false;
 365
 366   // Replace the default NtMapViewOfSection with our patched version.
 367 #if defined(_WIN64)
 368   NTSTATUS ret = thunk->Setup(::GetModuleHandle(sandbox::kNtdllName),
 369                               reinterpret_cast<void*>(&__ImageBase),
 370                               "NtMapViewOfSection",
 371                               NULL,
 372                               &blacklist::BlNtMapViewOfSection64,
 373                               thunk_storage,
 374                               sizeof(sandbox::ThunkData),
 375                               NULL);
 376
 377   // Keep a pointer to the original code, we don't have enough space to
 378   // add it directly to the call.
 379   g_nt_map_view_of_section_func = reinterpret_cast<NtMapViewOfSectionFunction>(
 380       thunk_storage);
 381
 382   // Ensure that the pointer to the old function can't be changed.
 383  page_executable = VirtualProtect(&g_nt_map_view_of_section_func,
 384                                   sizeof(g_nt_map_view_of_section_func),
 385                                   PAGE_EXECUTE_READ,
 386                                   &old_protect);
 387 #else
 388   NTSTATUS ret = thunk->Setup(::GetModuleHandle(sandbox::kNtdllName),
 389                               reinterpret_cast<void*>(&__ImageBase),
 390                               "NtMapViewOfSection",
 391                               NULL,
 392                               &blacklist::BlNtMapViewOfSection,
 393                               thunk_storage,
 394                               sizeof(sandbox::ThunkData),
 395                               NULL);
 396 #endif
 397   delete thunk;
 398
 399   // Record if we have initialized the blacklist.
 400   g_blacklist_initialized = NT_SUCCESS(ret);
 401
 402   // Mark the thunk storage as executable and prevent any future writes to it.
 403   page_executable = page_executable && VirtualProtect(&g_thunk_storage,
 404                                                       sizeof(g_thunk_storage),
 405                                                       PAGE_EXECUTE_READ,
 406                                                       &old_protect);
 407
 408   AddDllsFromRegistryToBlacklist();
 409
 410   return NT_SUCCESS(ret) && page_executable;
 411 }
 412
 413 void AddDllsFromRegistryToBlacklist() {
 414   HKEY key = NULL;
 415   LONG result = ::RegOpenKeyEx(HKEY_CURRENT_USER,
 416                                kRegistryFinchListPath,
 417                                0,
 418                                KEY_QUERY_VALUE | KEY_SET_VALUE,
 419                                &key);
 420
 421   if (result != ERROR_SUCCESS)
 422     return;
 423
 424   // We add dlls from the registry to the blacklist.
 425   DWORD value_len;
 426   DWORD name_len = MAX_PATH;
 427   std::vector<wchar_t> name_buffer(name_len);
 428   for (int i = 0; result == ERROR_SUCCESS; ++i) {
 429     name_len = MAX_PATH;
 430     value_len = 0;
 431     result = ::RegEnumValue(
 432         key, i, &name_buffer[0], &name_len, NULL, NULL, NULL, &value_len);
 433     if (result != ERROR_SUCCESS)
 434       break;
 435
 436     name_len = name_len + 1;
 437     value_len = value_len + 1;
 438     std::vector<wchar_t> value_buffer(value_len);
 439     result = ::RegEnumValue(key, i, &name_buffer[0], &name_len, NULL, NULL,
 440                             reinterpret_cast<BYTE*>(&value_buffer[0]),
 441                             &value_len);
 442     if (result != ERROR_SUCCESS)
 443       break;
 444     value_buffer[value_len - 1] = L'\0';
 445     AddDllToBlacklist(&value_buffer[0]);
 446   }
 447
 448   ::RegCloseKey(key);
 449   return;
 450 }
 451
 452 }  // namespace blacklist