src/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"chrmxtn.dll",                       // Unknown (keystroke logger).
  40   L"cplushook.dll",                     // Unknown (suspected malware).
  41   L"datamngr.dll",                      // Unknown (suspected adware).
  42   L"hk.dll",                            // Unknown (keystroke logger).
  43   L"libapi2hook.dll",                   // V-Bates.
  44   L"libinject.dll",                     // V-Bates.
  45   L"libinject2.dll",                    // V-Bates.
  46   L"libredir2.dll",                     // V-Bates.
  47   L"libsvn_tsvn32.dll",                 // TortoiseSVN.
  48   L"libwinhook.dll",                    // V-Bates.
  49   L"lmrn.dll",                          // Unknown.
  50   L"minisp.dll",                        // Unknown (suspected malware).
  51   L"scdetour.dll",                      // Quick Heal Antivirus.
  52                                         // See crbug.com/382561.
  53   L"systemk.dll",                       // Unknown (suspected adware).
  54   L"windowsapihookdll32.dll",           // Lenovo One Key Theater.
  55                                         // See crbug.com/379218.
  56   L"windowsapihookdll64.dll",           // Lenovo One Key Theater.
  57   // Keep this null pointer here to mark the end of the list.
  58   NULL,
  59 };
  60
  61 bool g_blocked_dlls[kTroublesomeDllsMaxCount] = {};
  62 int g_num_blocked_dlls = 0;
  63
  64 }  // namespace blacklist
  65
  66 // Allocate storage for thunks in a page of this module to save on doing
  67 // an extra allocation at run time.
  68 #pragma section(".crthunk",read,execute)
  69 __declspec(allocate(".crthunk")) sandbox::ThunkData g_thunk_storage;
  70
  71 namespace {
  72
  73 // Record if the blacklist was successfully initialized so processes can easily
  74 // determine if the blacklist is enabled for them.
  75 bool g_blacklist_initialized = false;
  76
  77 // Helper to set DWORD registry values.
  78 DWORD SetDWValue(HKEY* key, const wchar_t* property, DWORD value) {
  79   return ::RegSetValueEx(*key,
  80                          property,
  81                          0,
  82                          REG_DWORD,
  83                          reinterpret_cast<LPBYTE>(&value),
  84                          sizeof(value));
  85 }
  86
  87 bool GenerateStateFromBeaconAndAttemptCount(HKEY* key, DWORD blacklist_state) {
  88   LONG result = 0;
  89   if (blacklist_state == blacklist::BLACKLIST_ENABLED) {
  90     // If the blacklist succeeded on the previous run reset the failure
  91     // counter.
  92     return (SetDWValue(key,
  93                        blacklist::kBeaconAttemptCount,
  94                        static_cast<DWORD>(0)) == ERROR_SUCCESS);
  95   } else {
  96     // Some part of the blacklist setup failed last time.  If this has occured
  97     // blacklist::kBeaconMaxAttempts times in a row we switch the state to
  98     // failed and skip setting up the blacklist.
  99     DWORD attempt_count = 0;
 100     DWORD attempt_count_size = sizeof(attempt_count);
 101     result = ::RegQueryValueEx(*key,
 102                                blacklist::kBeaconAttemptCount,
 103                                0,
 104                                NULL,
 105                                reinterpret_cast<LPBYTE>(&attempt_count),
 106                                &attempt_count_size);
 107
 108     if (result == ERROR_FILE_NOT_FOUND)
 109       attempt_count = 0;
 110     else if (result != ERROR_SUCCESS)
 111       return false;
 112
 113     ++attempt_count;
 114     SetDWValue(key, blacklist::kBeaconAttemptCount, attempt_count);
 115
 116     if (attempt_count >= blacklist::kBeaconMaxAttempts) {
 117       blacklist_state = blacklist::BLACKLIST_SETUP_FAILED;
 118       SetDWValue(key, blacklist::kBeaconState, blacklist_state);
 119     }
 120
 121     return false;
 122   }
 123 }
 124
 125 }  // namespace
 126
 127 namespace blacklist {
 128
 129 #if defined(_WIN64)
 130   // Allocate storage for the pointer to the old NtMapViewOfSectionFunction.
 131 #pragma section(".oldntmap",write,read)
 132   __declspec(allocate(".oldntmap"))
 133     NtMapViewOfSectionFunction g_nt_map_view_of_section_func = NULL;
 134 #endif
 135
 136 bool LeaveSetupBeacon() {
 137   HKEY key = NULL;
 138   DWORD disposition = 0;
 139   LONG result = ::RegCreateKeyEx(HKEY_CURRENT_USER,
 140                                  kRegistryBeaconPath,
 141                                  0,
 142                                  NULL,
 143                                  REG_OPTION_NON_VOLATILE,
 144                                  KEY_QUERY_VALUE | KEY_SET_VALUE,
 145                                  NULL,
 146                                  &key,
 147                                  &disposition);
 148   if (result != ERROR_SUCCESS)
 149     return false;
 150
 151   // Retrieve the current blacklist state.
 152   DWORD blacklist_state = BLACKLIST_STATE_MAX;
 153   DWORD blacklist_state_size = sizeof(blacklist_state);
 154   DWORD type = 0;
 155   result = ::RegQueryValueEx(key,
 156                              kBeaconState,
 157                              0,
 158                              &type,
 159                              reinterpret_cast<LPBYTE>(&blacklist_state),
 160                              &blacklist_state_size);
 161
 162   if (blacklist_state == BLACKLIST_DISABLED || result != ERROR_SUCCESS ||
 163       type != REG_DWORD) {
 164     ::RegCloseKey(key);
 165     return false;
 166   }
 167
 168   if (!GenerateStateFromBeaconAndAttemptCount(&key, blacklist_state)) {
 169     ::RegCloseKey(key);
 170     return false;
 171   }
 172
 173   result = SetDWValue(&key, kBeaconState, BLACKLIST_SETUP_RUNNING);
 174   ::RegCloseKey(key);
 175
 176   return (result == ERROR_SUCCESS);
 177 }
 178
 179 bool ResetBeacon() {
 180   HKEY key = NULL;
 181   DWORD disposition = 0;
 182   LONG result = ::RegCreateKeyEx(HKEY_CURRENT_USER,
 183                                  kRegistryBeaconPath,
 184                                  0,
 185                                  NULL,
 186                                  REG_OPTION_NON_VOLATILE,
 187                                  KEY_QUERY_VALUE | KEY_SET_VALUE,
 188                                  NULL,
 189                                  &key,
 190                                  &disposition);
 191   if (result != ERROR_SUCCESS)
 192     return false;
 193
 194   DWORD blacklist_state = BLACKLIST_STATE_MAX;
 195   DWORD blacklist_state_size = sizeof(blacklist_state);
 196   DWORD type = 0;
 197   result = ::RegQueryValueEx(key,
 198                              kBeaconState,
 199                              0,
 200                              &type,
 201                              reinterpret_cast<LPBYTE>(&blacklist_state),
 202                              &blacklist_state_size);
 203
 204   if (result != ERROR_SUCCESS || type != REG_DWORD) {
 205     ::RegCloseKey(key);
 206     return false;
 207   }
 208
 209   // Reaching this point with the setup running state means the setup did not
 210   // crash, so we reset to enabled.  Any other state indicates that setup was
 211   // skipped; in that case we leave the state alone for later recording.
 212   if (blacklist_state == BLACKLIST_SETUP_RUNNING)
 213     result = SetDWValue(&key, kBeaconState, BLACKLIST_ENABLED);
 214
 215   ::RegCloseKey(key);
 216   return (result == ERROR_SUCCESS);
 217 }
 218
 219 int BlacklistSize() {
 220   int size = -1;
 221   while (blacklist::g_troublesome_dlls[++size] != NULL) {}
 222
 223   return size;
 224 }
 225
 226 bool IsBlacklistInitialized() {
 227   return g_blacklist_initialized;
 228 }
 229
 230 int GetBlacklistIndex(const wchar_t* dll_name) {
 231   for (int i = 0; i < kTroublesomeDllsMaxCount, g_troublesome_dlls[i]; ++i) {
 232     if (_wcsicmp(dll_name, g_troublesome_dlls[i]) == 0)
 233       return i;
 234   }
 235   return -1;
 236 }
 237
 238 bool AddDllToBlacklist(const wchar_t* dll_name) {
 239   int blacklist_size = BlacklistSize();
 240   // We need to leave one space at the end for the null pointer.
 241   if (blacklist_size + 1 >= kTroublesomeDllsMaxCount)
 242     return false;
 243   for (int i = 0; i < blacklist_size; ++i) {
 244     if (!_wcsicmp(g_troublesome_dlls[i], dll_name))
 245       return true;
 246   }
 247
 248   // Copy string to blacklist.
 249   wchar_t* str_buffer = new wchar_t[wcslen(dll_name) + 1];
 250   wcscpy(str_buffer, dll_name);
 251
 252   g_troublesome_dlls[blacklist_size] = str_buffer;
 253   g_blocked_dlls[blacklist_size] = false;
 254   return true;
 255 }
 256
 257 bool RemoveDllFromBlacklist(const wchar_t* dll_name) {
 258   int blacklist_size = BlacklistSize();
 259   for (int i = 0; i < blacklist_size; ++i) {
 260     if (!_wcsicmp(g_troublesome_dlls[i], dll_name)) {
 261       // Found the thing to remove. Delete it then replace it with the last
 262       // element.
 263       delete[] g_troublesome_dlls[i];
 264       g_troublesome_dlls[i] = g_troublesome_dlls[blacklist_size - 1];
 265       g_troublesome_dlls[blacklist_size - 1] = NULL;
 266
 267       // Also update the stats recording if we have blocked this dll or not.
 268       if (g_blocked_dlls[i])
 269         --g_num_blocked_dlls;
 270       g_blocked_dlls[i] = g_blocked_dlls[blacklist_size - 1];
 271       return true;
 272     }
 273   }
 274   return false;
 275 }
 276
 277 // TODO(csharp): Maybe store these values in the registry so we can
 278 // still report them if Chrome crashes early.
 279 void SuccessfullyBlocked(const wchar_t** blocked_dlls, int* size) {
 280   if (size == NULL)
 281     return;
 282
 283   // If the array isn't valid or big enough, just report the size it needs to
 284   // be and return.
 285   if (blocked_dlls == NULL && *size < g_num_blocked_dlls) {
 286     *size = g_num_blocked_dlls;
 287     return;
 288   }
 289
 290   *size = g_num_blocked_dlls;
 291
 292   int strings_to_fill = 0;
 293   for (int i = 0; strings_to_fill < g_num_blocked_dlls && g_troublesome_dlls[i];
 294        ++i) {
 295     if (g_blocked_dlls[i]) {
 296       blocked_dlls[strings_to_fill] = g_troublesome_dlls[i];
 297       ++strings_to_fill;
 298     }
 299   }
 300 }
 301
 302 void BlockedDll(size_t blocked_index) {
 303   assert(blocked_index < kTroublesomeDllsMaxCount);
 304
 305   if (!g_blocked_dlls[blocked_index] &&
 306       blocked_index < kTroublesomeDllsMaxCount) {
 307     ++g_num_blocked_dlls;
 308     g_blocked_dlls[blocked_index] = true;
 309   }
 310 }
 311
 312 bool Initialize(bool force) {
 313   // Check to see that we found the functions we need in ntdll.
 314   if (!InitializeInterceptImports())
 315     return false;
 316
 317   // Check to see if this is a non-browser process, abort if so.
 318   if (IsNonBrowserProcess())
 319     return false;
 320
 321   // Check to see if the blacklist beacon is still set to running (indicating a
 322   // failure) or disabled, and abort if so.
 323   if (!force && !LeaveSetupBeacon())
 324     return false;
 325
 326   // It is possible for other dlls to have already patched code by now and
 327   // attempting to patch their code might result in crashes.
 328   const bool kRelaxed = false;
 329
 330   // Create a thunk via the appropriate ServiceResolver instance.
 331   sandbox::ServiceResolverThunk* thunk = GetThunk(kRelaxed);
 332
 333   // Don't try blacklisting on unsupported OS versions.
 334   if (!thunk)
 335     return false;
 336
 337   BYTE* thunk_storage = reinterpret_cast<BYTE*>(&g_thunk_storage);
 338
 339   // Mark the thunk storage as readable and writeable, since we
 340   // ready to write to it.
 341   DWORD old_protect = 0;
 342   if (!VirtualProtect(&g_thunk_storage,
 343                       sizeof(g_thunk_storage),
 344                       PAGE_EXECUTE_READWRITE,
 345                       &old_protect)) {
 346     return false;
 347   }
 348
 349   thunk->AllowLocalPatches();
 350
 351   // We declare this early so it can be used in the 64-bit block below and
 352   // still work on 32-bit build when referenced at the end of the function.
 353   BOOL page_executable = false;
 354
 355   // Replace the default NtMapViewOfSection with our patched version.
 356 #if defined(_WIN64)
 357   NTSTATUS ret = thunk->Setup(::GetModuleHandle(sandbox::kNtdllName),
 358                               reinterpret_cast<void*>(&__ImageBase),
 359                               "NtMapViewOfSection",
 360                               NULL,
 361                               &blacklist::BlNtMapViewOfSection64,
 362                               thunk_storage,
 363                               sizeof(sandbox::ThunkData),
 364                               NULL);
 365
 366   // Keep a pointer to the original code, we don't have enough space to
 367   // add it directly to the call.
 368   g_nt_map_view_of_section_func = reinterpret_cast<NtMapViewOfSectionFunction>(
 369       thunk_storage);
 370
 371   // Ensure that the pointer to the old function can't be changed.
 372  page_executable = VirtualProtect(&g_nt_map_view_of_section_func,
 373                                   sizeof(g_nt_map_view_of_section_func),
 374                                   PAGE_EXECUTE_READ,
 375                                   &old_protect);
 376 #else
 377   NTSTATUS ret = thunk->Setup(::GetModuleHandle(sandbox::kNtdllName),
 378                               reinterpret_cast<void*>(&__ImageBase),
 379                               "NtMapViewOfSection",
 380                               NULL,
 381                               &blacklist::BlNtMapViewOfSection,
 382                               thunk_storage,
 383                               sizeof(sandbox::ThunkData),
 384                               NULL);
 385 #endif
 386   delete thunk;
 387
 388   // Record if we have initialized the blacklist.
 389   g_blacklist_initialized = NT_SUCCESS(ret);
 390
 391   // Mark the thunk storage as executable and prevent any future writes to it.
 392   page_executable = page_executable && VirtualProtect(&g_thunk_storage,
 393                                                       sizeof(g_thunk_storage),
 394                                                       PAGE_EXECUTE_READ,
 395                                                       &old_protect);
 396
 397   AddDllsFromRegistryToBlacklist();
 398
 399   return NT_SUCCESS(ret) && page_executable;
 400 }
 401
 402 void AddDllsFromRegistryToBlacklist() {
 403   HKEY key = NULL;
 404   LONG result = ::RegOpenKeyEx(HKEY_CURRENT_USER,
 405                                kRegistryFinchListPath,
 406                                0,
 407                                KEY_QUERY_VALUE | KEY_SET_VALUE,
 408                                &key);
 409
 410   if (result != ERROR_SUCCESS)
 411     return;
 412
 413   // We add dlls from the registry to the blacklist.
 414   DWORD value_len;
 415   DWORD name_len = MAX_PATH;
 416   std::vector<wchar_t> name_buffer(name_len);
 417   for (int i = 0; result == ERROR_SUCCESS; ++i) {
 418     name_len = MAX_PATH;
 419     value_len = 0;
 420     result = ::RegEnumValue(
 421         key, i, &name_buffer[0], &name_len, NULL, NULL, NULL, &value_len);
 422     if (result != ERROR_SUCCESS)
 423       break;
 424
 425     name_len = name_len + 1;
 426     value_len = value_len + 1;
 427     std::vector<wchar_t> value_buffer(value_len);
 428     result = ::RegEnumValue(key, i, &name_buffer[0], &name_len, NULL, NULL,
 429                             reinterpret_cast<BYTE*>(&value_buffer[0]),
 430                             &value_len);
 431     if (result != ERROR_SUCCESS)
 432       break;
 433     value_buffer[value_len - 1] = L'\0';
 434     AddDllToBlacklist(&value_buffer[0]);
 435   }
 436
 437   ::RegCloseKey(key);
 438   return;
 439 }
 440
 441 }  // namespace blacklist