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"dpinterface32.dll",                 // Unknown (suspected adware).
  46   L"explorerex.dll",                    // Unknown (suspected adware).
  47   L"hk.dll",                            // Unknown (keystroke logger).
  48   L"libapi2hook.dll",                   // V-Bates.
  49   L"libinject.dll",                     // V-Bates.
  50   L"libinject2.dll",                    // V-Bates.
  51   L"libredir2.dll",                     // V-Bates.
  52   L"libsvn_tsvn32.dll",                 // TortoiseSVN.
  53   L"libwinhook.dll",                    // V-Bates.
  54   L"lmrn.dll",                          // Unknown.
  55   L"minisp.dll",                        // Unknown (suspected malware).
  56   L"minisp32.dll",                      // Unknown (suspected malware).
  57   L"offerswizarddll.dll",               // Unknown (suspected adware).
  58   L"safetynut.dll",                     // Unknown (suspected adware).
  59   L"smdmf.dll",                         // Unknown (suspected adware).
  60   L"spappsv32.dll",                     // Unknown (suspected adware).
  61   L"systemk.dll",                       // Unknown (suspected adware).
  62   L"vntsrv.dll",                        // Virtual New Tab by APN LLC.
  63   L"wajam_goblin_64.dll",               // Wajam Internet Technologies.
  64   L"wajam_goblin.dll",                  // Wajam Internet Technologies.
  65   L"windowsapihookdll32.dll",           // Lenovo One Key Theater.
  66                                         // See crbug.com/379218.
  67   L"windowsapihookdll64.dll",           // Lenovo One Key Theater.
  68   L"virtualcamera.ax",                  // %PROGRAMFILES%\ASUS\VirtualCamera.
  69                                         // See crbug.com/422522.
  70   L"ycwebcamerasource.ax",              // CyberLink Youcam, crbug.com/424159
  71   // Keep this null pointer here to mark the end of the list.
  72   NULL,
  73 };
  74
  75 bool g_blocked_dlls[kTroublesomeDllsMaxCount] = {};
  76 int g_num_blocked_dlls = 0;
  77
  78 }  // namespace blacklist
  79
  80 // Allocate storage for thunks in a page of this module to save on doing
  81 // an extra allocation at run time.
  82 #pragma section(".crthunk",read,execute)
  83 __declspec(allocate(".crthunk")) sandbox::ThunkData g_thunk_storage;
  84
  85 namespace {
  86
  87 // Record if the blacklist was successfully initialized so processes can easily
  88 // determine if the blacklist is enabled for them.
  89 bool g_blacklist_initialized = false;
  90
  91 // Helper to set DWORD registry values.
  92 DWORD SetDWValue(HKEY* key, const wchar_t* property, DWORD value) {
  93   return ::RegSetValueEx(*key,
  94                          property,
  95                          0,
  96                          REG_DWORD,
  97                          reinterpret_cast<LPBYTE>(&value),
  98                          sizeof(value));
  99 }
 100
 101 bool GenerateStateFromBeaconAndAttemptCount(HKEY* key, DWORD blacklist_state) {
 102   LONG result = 0;
 103   if (blacklist_state == blacklist::BLACKLIST_ENABLED) {
 104     // If the blacklist succeeded on the previous run reset the failure
 105     // counter.
 106     return (SetDWValue(key,
 107                        blacklist::kBeaconAttemptCount,
 108                        static_cast<DWORD>(0)) == ERROR_SUCCESS);
 109   } else {
 110     // Some part of the blacklist setup failed last time.  If this has occured
 111     // blacklist::kBeaconMaxAttempts times in a row we switch the state to
 112     // failed and skip setting up the blacklist.
 113     DWORD attempt_count = 0;
 114     DWORD attempt_count_size = sizeof(attempt_count);
 115     result = ::RegQueryValueEx(*key,
 116                                blacklist::kBeaconAttemptCount,
 117                                0,
 118                                NULL,
 119                                reinterpret_cast<LPBYTE>(&attempt_count),
 120                                &attempt_count_size);
 121
 122     if (result == ERROR_FILE_NOT_FOUND)
 123       attempt_count = 0;
 124     else if (result != ERROR_SUCCESS)
 125       return false;
 126
 127     ++attempt_count;
 128     SetDWValue(key, blacklist::kBeaconAttemptCount, attempt_count);
 129
 130     if (attempt_count >= blacklist::kBeaconMaxAttempts) {
 131       blacklist_state = blacklist::BLACKLIST_SETUP_FAILED;
 132       SetDWValue(key, blacklist::kBeaconState, blacklist_state);
 133     }
 134
 135     return false;
 136   }
 137 }
 138
 139 }  // namespace
 140
 141 namespace blacklist {
 142
 143 #if defined(_WIN64)
 144   // Allocate storage for the pointer to the old NtMapViewOfSectionFunction.
 145 #pragma section(".oldntmap",write,read)
 146   __declspec(allocate(".oldntmap"))
 147     NtMapViewOfSectionFunction g_nt_map_view_of_section_func = NULL;
 148 #endif
 149
 150 bool LeaveSetupBeacon() {
 151   HKEY key = NULL;
 152   DWORD disposition = 0;
 153   LONG result = ::RegCreateKeyEx(HKEY_CURRENT_USER,
 154                                  kRegistryBeaconPath,
 155                                  0,
 156                                  NULL,
 157                                  REG_OPTION_NON_VOLATILE,
 158                                  KEY_QUERY_VALUE | KEY_SET_VALUE,
 159                                  NULL,
 160                                  &key,
 161                                  &disposition);
 162   if (result != ERROR_SUCCESS)
 163     return false;
 164
 165   // Retrieve the current blacklist state.
 166   DWORD blacklist_state = BLACKLIST_STATE_MAX;
 167   DWORD blacklist_state_size = sizeof(blacklist_state);
 168   DWORD type = 0;
 169   result = ::RegQueryValueEx(key,
 170                              kBeaconState,
 171                              0,
 172                              &type,
 173                              reinterpret_cast<LPBYTE>(&blacklist_state),
 174                              &blacklist_state_size);
 175
 176   if (result != ERROR_SUCCESS || blacklist_state == BLACKLIST_DISABLED ||
 177       type != REG_DWORD) {
 178     ::RegCloseKey(key);
 179     return false;
 180   }
 181
 182   if (!GenerateStateFromBeaconAndAttemptCount(&key, blacklist_state)) {
 183     ::RegCloseKey(key);
 184     return false;
 185   }
 186
 187   result = SetDWValue(&key, kBeaconState, BLACKLIST_SETUP_RUNNING);
 188   ::RegCloseKey(key);
 189
 190   return (result == ERROR_SUCCESS);
 191 }
 192
 193 bool ResetBeacon() {
 194   HKEY key = NULL;
 195   DWORD disposition = 0;
 196   LONG result = ::RegCreateKeyEx(HKEY_CURRENT_USER,
 197                                  kRegistryBeaconPath,
 198                                  0,
 199                                  NULL,
 200                                  REG_OPTION_NON_VOLATILE,
 201                                  KEY_QUERY_VALUE | KEY_SET_VALUE,
 202                                  NULL,
 203                                  &key,
 204                                  &disposition);
 205   if (result != ERROR_SUCCESS)
 206     return false;
 207
 208   DWORD blacklist_state = BLACKLIST_STATE_MAX;
 209   DWORD blacklist_state_size = sizeof(blacklist_state);
 210   DWORD type = 0;
 211   result = ::RegQueryValueEx(key,
 212                              kBeaconState,
 213                              0,
 214                              &type,
 215                              reinterpret_cast<LPBYTE>(&blacklist_state),
 216                              &blacklist_state_size);
 217
 218   if (result != ERROR_SUCCESS || type != REG_DWORD) {
 219     ::RegCloseKey(key);
 220     return false;
 221   }
 222
 223   // Reaching this point with the setup running state means the setup did not
 224   // crash, so we reset to enabled.  Any other state indicates that setup was
 225   // skipped; in that case we leave the state alone for later recording.
 226   if (blacklist_state == BLACKLIST_SETUP_RUNNING)
 227     result = SetDWValue(&key, kBeaconState, BLACKLIST_ENABLED);
 228
 229   ::RegCloseKey(key);
 230   return (result == ERROR_SUCCESS);
 231 }
 232
 233 int BlacklistSize() {
 234   int size = -1;
 235   while (blacklist::g_troublesome_dlls[++size] != NULL) {}
 236
 237   return size;
 238 }
 239
 240 bool IsBlacklistInitialized() {
 241   return g_blacklist_initialized;
 242 }
 243
 244 int GetBlacklistIndex(const wchar_t* dll_name) {
 245   for (int i = 0; i < kTroublesomeDllsMaxCount && g_troublesome_dlls[i]; ++i) {
 246     if (_wcsicmp(dll_name, g_troublesome_dlls[i]) == 0)
 247       return i;
 248   }
 249   return -1;
 250 }
 251
 252 bool AddDllToBlacklist(const wchar_t* dll_name) {
 253   int blacklist_size = BlacklistSize();
 254   // We need to leave one space at the end for the null pointer.
 255   if (blacklist_size + 1 >= kTroublesomeDllsMaxCount)
 256     return false;
 257   for (int i = 0; i < blacklist_size; ++i) {
 258     if (!_wcsicmp(g_troublesome_dlls[i], dll_name))
 259       return true;
 260   }
 261
 262   // Copy string to blacklist.
 263   wchar_t* str_buffer = new wchar_t[wcslen(dll_name) + 1];
 264   wcscpy(str_buffer, dll_name);
 265
 266   g_troublesome_dlls[blacklist_size] = str_buffer;
 267   g_blocked_dlls[blacklist_size] = false;
 268   return true;
 269 }
 270
 271 bool RemoveDllFromBlacklist(const wchar_t* dll_name) {
 272   int blacklist_size = BlacklistSize();
 273   for (int i = 0; i < blacklist_size; ++i) {
 274     if (!_wcsicmp(g_troublesome_dlls[i], dll_name)) {
 275       // Found the thing to remove. Delete it then replace it with the last
 276       // element.
 277       delete[] g_troublesome_dlls[i];
 278       g_troublesome_dlls[i] = g_troublesome_dlls[blacklist_size - 1];
 279       g_troublesome_dlls[blacklist_size - 1] = NULL;
 280
 281       // Also update the stats recording if we have blocked this dll or not.
 282       if (g_blocked_dlls[i])
 283         --g_num_blocked_dlls;
 284       g_blocked_dlls[i] = g_blocked_dlls[blacklist_size - 1];
 285       return true;
 286     }
 287   }
 288   return false;
 289 }
 290
 291 // TODO(csharp): Maybe store these values in the registry so we can
 292 // still report them if Chrome crashes early.
 293 void SuccessfullyBlocked(const wchar_t** blocked_dlls, int* size) {
 294   if (size == NULL)
 295     return;
 296
 297   // If the array isn't valid or big enough, just report the size it needs to
 298   // be and return.
 299   if (blocked_dlls == NULL && *size < g_num_blocked_dlls) {
 300     *size = g_num_blocked_dlls;
 301     return;
 302   }
 303
 304   *size = g_num_blocked_dlls;
 305
 306   int strings_to_fill = 0;
 307   for (int i = 0; strings_to_fill < g_num_blocked_dlls && g_troublesome_dlls[i];
 308        ++i) {
 309     if (g_blocked_dlls[i]) {
 310       blocked_dlls[strings_to_fill] = g_troublesome_dlls[i];
 311       ++strings_to_fill;
 312     }
 313   }
 314 }
 315
 316 void BlockedDll(size_t blocked_index) {
 317   assert(blocked_index < kTroublesomeDllsMaxCount);
 318
 319   if (!g_blocked_dlls[blocked_index] &&
 320       blocked_index < kTroublesomeDllsMaxCount) {
 321     ++g_num_blocked_dlls;
 322     g_blocked_dlls[blocked_index] = true;
 323   }
 324 }
 325
 326 bool Initialize(bool force) {
 327   // Check to see that we found the functions we need in ntdll.
 328   if (!InitializeInterceptImports())
 329     return false;
 330
 331   // Check to see if this is a non-browser process, abort if so.
 332   if (IsNonBrowserProcess())
 333     return false;
 334
 335   // Check to see if the blacklist beacon is still set to running (indicating a
 336   // failure) or disabled, and abort if so.
 337   if (!force && !LeaveSetupBeacon())
 338     return false;
 339
 340   // It is possible for other dlls to have already patched code by now and
 341   // attempting to patch their code might result in crashes.
 342   const bool kRelaxed = false;
 343
 344   // Create a thunk via the appropriate ServiceResolver instance.
 345   sandbox::ServiceResolverThunk* thunk = GetThunk(kRelaxed);
 346
 347   // Don't try blacklisting on unsupported OS versions.
 348   if (!thunk)
 349     return false;
 350
 351   BYTE* thunk_storage = reinterpret_cast<BYTE*>(&g_thunk_storage);
 352
 353   // Mark the thunk storage as readable and writeable, since we
 354   // ready to write to it.
 355   DWORD old_protect = 0;
 356   if (!VirtualProtect(&g_thunk_storage,
 357                       sizeof(g_thunk_storage),
 358                       PAGE_EXECUTE_READWRITE,
 359                       &old_protect)) {
 360     return false;
 361   }
 362
 363   thunk->AllowLocalPatches();
 364
 365   // We declare this early so it can be used in the 64-bit block below and
 366   // still work on 32-bit build when referenced at the end of the function.
 367   BOOL page_executable = false;
 368
 369   // Replace the default NtMapViewOfSection with our patched version.
 370 #if defined(_WIN64)
 371   NTSTATUS ret = thunk->Setup(::GetModuleHandle(sandbox::kNtdllName),
 372                               reinterpret_cast<void*>(&__ImageBase),
 373                               "NtMapViewOfSection",
 374                               NULL,
 375                               &blacklist::BlNtMapViewOfSection64,
 376                               thunk_storage,
 377                               sizeof(sandbox::ThunkData),
 378                               NULL);
 379
 380   // Keep a pointer to the original code, we don't have enough space to
 381   // add it directly to the call.
 382   g_nt_map_view_of_section_func = reinterpret_cast<NtMapViewOfSectionFunction>(
 383       thunk_storage);
 384
 385   // Ensure that the pointer to the old function can't be changed.
 386  page_executable = VirtualProtect(&g_nt_map_view_of_section_func,
 387                                   sizeof(g_nt_map_view_of_section_func),
 388                                   PAGE_EXECUTE_READ,
 389                                   &old_protect);
 390 #else
 391   NTSTATUS ret = thunk->Setup(::GetModuleHandle(sandbox::kNtdllName),
 392                               reinterpret_cast<void*>(&__ImageBase),
 393                               "NtMapViewOfSection",
 394                               NULL,
 395                               &blacklist::BlNtMapViewOfSection,
 396                               thunk_storage,
 397                               sizeof(sandbox::ThunkData),
 398                               NULL);
 399 #endif
 400   delete thunk;
 401
 402   // Record if we have initialized the blacklist.
 403   g_blacklist_initialized = NT_SUCCESS(ret);
 404
 405   // Mark the thunk storage as executable and prevent any future writes to it.
 406   page_executable = page_executable && VirtualProtect(&g_thunk_storage,
 407                                                       sizeof(g_thunk_storage),
 408                                                       PAGE_EXECUTE_READ,
 409                                                       &old_protect);
 410
 411   AddDllsFromRegistryToBlacklist();
 412
 413   return NT_SUCCESS(ret) && page_executable;
 414 }
 415
 416 void AddDllsFromRegistryToBlacklist() {
 417   HKEY key = NULL;
 418   LONG result = ::RegOpenKeyEx(HKEY_CURRENT_USER,
 419                                kRegistryFinchListPath,
 420                                0,
 421                                KEY_QUERY_VALUE | KEY_SET_VALUE,
 422                                &key);
 423
 424   if (result != ERROR_SUCCESS)
 425     return;
 426
 427   // We add dlls from the registry to the blacklist.
 428   DWORD value_len;
 429   DWORD name_len = MAX_PATH;
 430   std::vector<wchar_t> name_buffer(name_len);
 431   for (int i = 0; result == ERROR_SUCCESS; ++i) {
 432     name_len = MAX_PATH;
 433     value_len = 0;
 434     result = ::RegEnumValue(
 435         key, i, &name_buffer[0], &name_len, NULL, NULL, NULL, &value_len);
 436     if (result != ERROR_SUCCESS)
 437       break;
 438
 439     name_len = name_len + 1;
 440     value_len = value_len + 1;
 441     std::vector<wchar_t> value_buffer(value_len);
 442     result = ::RegEnumValue(key, i, &name_buffer[0], &name_len, NULL, NULL,
 443                             reinterpret_cast<BYTE*>(&value_buffer[0]),
 444                             &value_len);
 445     if (result != ERROR_SUCCESS)
 446       break;
 447     value_buffer[value_len - 1] = L'\0';
 448     AddDllToBlacklist(&value_buffer[0]);
 449   }
 450
 451   ::RegCloseKey(key);
 452   return;
 453 }
 454
 455 }  // namespace blacklist