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