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"cespy.dll",                         // CovenantEyes.
  40   L"chrmxtn.dll",                       // Unknown (keystroke logger).
  41   L"cplushook.dll",                     // Unknown (suspected malware).
  42   L"datamngr.dll",                      // Unknown (suspected adware).
  43   L"hk.dll",                            // Unknown (keystroke logger).
  44   L"libapi2hook.dll",                   // V-Bates.
  45   L"libinject.dll",                     // V-Bates.
  46   L"libinject2.dll",                    // V-Bates.
  47   L"libredir2.dll",                     // V-Bates.
  48   L"libsvn_tsvn32.dll",                 // TortoiseSVN.
  49   L"libwinhook.dll",                    // V-Bates.
  50   L"lmrn.dll",                          // Unknown.
  51   L"minisp.dll",                        // Unknown (suspected malware).
  52   L"scdetour.dll",                      // Quick Heal Antivirus.
  53                                         // See crbug.com/382561.
  54   L"systemk.dll",                       // Unknown (suspected adware).
  55   L"windowsapihookdll32.dll",           // Lenovo One Key Theater.
  56                                         // See crbug.com/379218.
  57   L"windowsapihookdll64.dll",           // Lenovo One Key Theater.
  58   // Keep this null pointer here to mark the end of the list.
  59   NULL,
  60 };
  61
  62 bool g_blocked_dlls[kTroublesomeDllsMaxCount] = {};
  63 int g_num_blocked_dlls = 0;
  64
  65 }  // namespace blacklist
  66
  67 // Allocate storage for thunks in a page of this module to save on doing
  68 // an extra allocation at run time.
  69 #pragma section(".crthunk",read,execute)
  70 __declspec(allocate(".crthunk")) sandbox::ThunkData g_thunk_storage;
  71
  72 namespace {
  73
  74 // Record if the blacklist was successfully initialized so processes can easily
  75 // determine if the blacklist is enabled for them.
  76 bool g_blacklist_initialized = false;
  77
  78 // Helper to set DWORD registry values.
  79 DWORD SetDWValue(HKEY* key, const wchar_t* property, DWORD value) {
  80   return ::RegSetValueEx(*key,
  81                          property,
  82                          0,
  83                          REG_DWORD,
  84                          reinterpret_cast<LPBYTE>(&value),
  85                          sizeof(value));
  86 }
  87
  88 bool GenerateStateFromBeaconAndAttemptCount(HKEY* key, DWORD blacklist_state) {
  89   LONG result = 0;
  90   if (blacklist_state == blacklist::BLACKLIST_SETUP_RUNNING) {
  91     // Some part of the blacklist setup failed last time.  If this has occured
  92     // blacklist::kBeaconMaxAttempts times in a row we switch the state to
  93     // failed and skip setting up the blacklist.
  94     DWORD attempt_count = 0;
  95     DWORD attempt_count_size = sizeof(attempt_count);
  96     result = ::RegQueryValueEx(*key,
  97                                blacklist::kBeaconAttemptCount,
  98                                0,
  99                                NULL,
 100                                reinterpret_cast<LPBYTE>(&attempt_count),
 101                                &attempt_count_size);
 102
 103     if (result == ERROR_FILE_NOT_FOUND)
 104       attempt_count = 0;
 105     else if (result != ERROR_SUCCESS)
 106       return false;
 107
 108     ++attempt_count;
 109     SetDWValue(key, blacklist::kBeaconAttemptCount, attempt_count);
 110
 111     if (attempt_count >= blacklist::kBeaconMaxAttempts) {
 112       blacklist_state = blacklist::BLACKLIST_SETUP_FAILED;
 113       SetDWValue(key, blacklist::kBeaconState, blacklist_state);
 114       return false;
 115     }
 116   } else if (blacklist_state == blacklist::BLACKLIST_ENABLED) {
 117     // If the blacklist succeeded on the previous run reset the failure
 118     // counter.
 119     result =
 120         SetDWValue(key, blacklist::kBeaconAttemptCount, static_cast<DWORD>(0));
 121     if (result != ERROR_SUCCESS) {
 122       return false;
 123     }
 124   }
 125   return true;
 126 }
 127
 128 }  // namespace
 129
 130 namespace blacklist {
 131
 132 #if defined(_WIN64)
 133   // Allocate storage for the pointer to the old NtMapViewOfSectionFunction.
 134 #pragma section(".oldntmap",write,read)
 135   __declspec(allocate(".oldntmap"))
 136     NtMapViewOfSectionFunction g_nt_map_view_of_section_func = NULL;
 137 #endif
 138
 139 bool LeaveSetupBeacon() {
 140   HKEY key = NULL;
 141   DWORD disposition = 0;
 142   LONG result = ::RegCreateKeyEx(HKEY_CURRENT_USER,
 143                                  kRegistryBeaconPath,
 144                                  0,
 145                                  NULL,
 146                                  REG_OPTION_NON_VOLATILE,
 147                                  KEY_QUERY_VALUE | KEY_SET_VALUE,
 148                                  NULL,
 149                                  &key,
 150                                  &disposition);
 151   if (result != ERROR_SUCCESS)
 152     return false;
 153
 154   // Retrieve the current blacklist state.
 155   DWORD blacklist_state = BLACKLIST_STATE_MAX;
 156   DWORD blacklist_state_size = sizeof(blacklist_state);
 157   DWORD type = 0;
 158   result = ::RegQueryValueEx(key,
 159                              kBeaconState,
 160                              0,
 161                              &type,
 162                              reinterpret_cast<LPBYTE>(&blacklist_state),
 163                              &blacklist_state_size);
 164
 165   if (blacklist_state == BLACKLIST_DISABLED || result != ERROR_SUCCESS ||
 166       type != REG_DWORD) {
 167     ::RegCloseKey(key);
 168     return false;
 169   }
 170
 171   if (!GenerateStateFromBeaconAndAttemptCount(&key, blacklist_state)) {
 172     ::RegCloseKey(key);
 173     return false;
 174   }
 175
 176   result = SetDWValue(&key, kBeaconState, BLACKLIST_SETUP_RUNNING);
 177   ::RegCloseKey(key);
 178
 179   return (result == ERROR_SUCCESS);
 180 }
 181
 182 bool ResetBeacon() {
 183   HKEY key = NULL;
 184   DWORD disposition = 0;
 185   LONG result = ::RegCreateKeyEx(HKEY_CURRENT_USER,
 186                                  kRegistryBeaconPath,
 187                                  0,
 188                                  NULL,
 189                                  REG_OPTION_NON_VOLATILE,
 190                                  KEY_QUERY_VALUE | KEY_SET_VALUE,
 191                                  NULL,
 192                                  &key,
 193                                  &disposition);
 194   if (result != ERROR_SUCCESS)
 195     return false;
 196
 197   DWORD blacklist_state = BLACKLIST_STATE_MAX;
 198   DWORD blacklist_state_size = sizeof(blacklist_state);
 199   DWORD type = 0;
 200   result = ::RegQueryValueEx(key,
 201                              kBeaconState,
 202                              0,
 203                              &type,
 204                              reinterpret_cast<LPBYTE>(&blacklist_state),
 205                              &blacklist_state_size);
 206
 207   if (result != ERROR_SUCCESS || type != REG_DWORD) {
 208     ::RegCloseKey(key);
 209     return false;
 210   }
 211
 212   // Reaching this point with the setup running state means the setup did not
 213   // crash, so we reset to enabled.  Any other state indicates that setup was
 214   // skipped; in that case we leave the state alone for later recording.
 215   if (blacklist_state == BLACKLIST_SETUP_RUNNING)
 216     result = SetDWValue(&key, kBeaconState, BLACKLIST_ENABLED);
 217
 218   ::RegCloseKey(key);
 219   return (result == ERROR_SUCCESS);
 220 }
 221
 222 int BlacklistSize() {
 223   int size = -1;
 224   while (blacklist::g_troublesome_dlls[++size] != NULL) {}
 225
 226   return size;
 227 }
 228
 229 bool IsBlacklistInitialized() {
 230   return g_blacklist_initialized;
 231 }
 232
 233 int GetBlacklistIndex(const wchar_t* dll_name) {
 234   for (int i = 0; i < kTroublesomeDllsMaxCount, g_troublesome_dlls[i]; ++i) {
 235     if (_wcsicmp(dll_name, g_troublesome_dlls[i]) == 0)
 236       return i;
 237   }
 238   return -1;
 239 }
 240
 241 bool AddDllToBlacklist(const wchar_t* dll_name) {
 242   int blacklist_size = BlacklistSize();
 243   // We need to leave one space at the end for the null pointer.
 244   if (blacklist_size + 1 >= kTroublesomeDllsMaxCount)
 245     return false;
 246   for (int i = 0; i < blacklist_size; ++i) {
 247     if (!_wcsicmp(g_troublesome_dlls[i], dll_name))
 248       return true;
 249   }
 250
 251   // Copy string to blacklist.
 252   wchar_t* str_buffer = new wchar_t[wcslen(dll_name) + 1];
 253   wcscpy(str_buffer, dll_name);
 254
 255   g_troublesome_dlls[blacklist_size] = str_buffer;
 256   g_blocked_dlls[blacklist_size] = false;
 257   return true;
 258 }
 259
 260 bool RemoveDllFromBlacklist(const wchar_t* dll_name) {
 261   int blacklist_size = BlacklistSize();
 262   for (int i = 0; i < blacklist_size; ++i) {
 263     if (!_wcsicmp(g_troublesome_dlls[i], dll_name)) {
 264       // Found the thing to remove. Delete it then replace it with the last
 265       // element.
 266       delete[] g_troublesome_dlls[i];
 267       g_troublesome_dlls[i] = g_troublesome_dlls[blacklist_size - 1];
 268       g_troublesome_dlls[blacklist_size - 1] = NULL;
 269
 270       // Also update the stats recording if we have blocked this dll or not.
 271       if (g_blocked_dlls[i])
 272         --g_num_blocked_dlls;
 273       g_blocked_dlls[i] = g_blocked_dlls[blacklist_size - 1];
 274       return true;
 275     }
 276   }
 277   return false;
 278 }
 279
 280 // TODO(csharp): Maybe store these values in the registry so we can
 281 // still report them if Chrome crashes early.
 282 void SuccessfullyBlocked(const wchar_t** blocked_dlls, int* size) {
 283   if (size == NULL)
 284     return;
 285
 286   // If the array isn't valid or big enough, just report the size it needs to
 287   // be and return.
 288   if (blocked_dlls == NULL && *size < g_num_blocked_dlls) {
 289     *size = g_num_blocked_dlls;
 290     return;
 291   }
 292
 293   *size = g_num_blocked_dlls;
 294
 295   int strings_to_fill = 0;
 296   for (int i = 0; strings_to_fill < g_num_blocked_dlls && g_troublesome_dlls[i];
 297        ++i) {
 298     if (g_blocked_dlls[i]) {
 299       blocked_dlls[strings_to_fill] = g_troublesome_dlls[i];
 300       ++strings_to_fill;
 301     }
 302   }
 303 }
 304
 305 void BlockedDll(size_t blocked_index) {
 306   assert(blocked_index < kTroublesomeDllsMaxCount);
 307
 308   if (!g_blocked_dlls[blocked_index] &&
 309       blocked_index < kTroublesomeDllsMaxCount) {
 310     ++g_num_blocked_dlls;
 311     g_blocked_dlls[blocked_index] = true;
 312   }
 313 }
 314
 315 bool Initialize(bool force) {
 316   // Check to see that we found the functions we need in ntdll.
 317   if (!InitializeInterceptImports())
 318     return false;
 319
 320   // Check to see if this is a non-browser process, abort if so.
 321   if (IsNonBrowserProcess())
 322     return false;
 323
 324   // Check to see if the blacklist beacon is still set to running (indicating a
 325   // failure) or disabled, and abort if so.
 326   if (!force && !LeaveSetupBeacon())
 327     return false;
 328
 329   // It is possible for other dlls to have already patched code by now and
 330   // attempting to patch their code might result in crashes.
 331   const bool kRelaxed = false;
 332
 333   // Create a thunk via the appropriate ServiceResolver instance.
 334   sandbox::ServiceResolverThunk* thunk = GetThunk(kRelaxed);
 335
 336   // Don't try blacklisting on unsupported OS versions.
 337   if (!thunk)
 338     return false;
 339
 340   BYTE* thunk_storage = reinterpret_cast<BYTE*>(&g_thunk_storage);
 341
 342   // Mark the thunk storage as readable and writeable, since we
 343   // ready to write to it.
 344   DWORD old_protect = 0;
 345   if (!VirtualProtect(&g_thunk_storage,
 346                       sizeof(g_thunk_storage),
 347                       PAGE_EXECUTE_READWRITE,
 348                       &old_protect)) {
 349     return false;
 350   }
 351
 352   thunk->AllowLocalPatches();
 353
 354   // We declare this early so it can be used in the 64-bit block below and
 355   // still work on 32-bit build when referenced at the end of the function.
 356   BOOL page_executable = false;
 357
 358   // Replace the default NtMapViewOfSection with our patched version.
 359 #if defined(_WIN64)
 360   NTSTATUS ret = thunk->Setup(::GetModuleHandle(sandbox::kNtdllName),
 361                               reinterpret_cast<void*>(&__ImageBase),
 362                               "NtMapViewOfSection",
 363                               NULL,
 364                               &blacklist::BlNtMapViewOfSection64,
 365                               thunk_storage,
 366                               sizeof(sandbox::ThunkData),
 367                               NULL);
 368
 369   // Keep a pointer to the original code, we don't have enough space to
 370   // add it directly to the call.
 371   g_nt_map_view_of_section_func = reinterpret_cast<NtMapViewOfSectionFunction>(
 372       thunk_storage);
 373
 374   // Ensure that the pointer to the old function can't be changed.
 375  page_executable = VirtualProtect(&g_nt_map_view_of_section_func,
 376                                   sizeof(g_nt_map_view_of_section_func),
 377                                   PAGE_EXECUTE_READ,
 378                                   &old_protect);
 379 #else
 380   NTSTATUS ret = thunk->Setup(::GetModuleHandle(sandbox::kNtdllName),
 381                               reinterpret_cast<void*>(&__ImageBase),
 382                               "NtMapViewOfSection",
 383                               NULL,
 384                               &blacklist::BlNtMapViewOfSection,
 385                               thunk_storage,
 386                               sizeof(sandbox::ThunkData),
 387                               NULL);
 388 #endif
 389   delete thunk;
 390
 391   // Record if we have initialized the blacklist.
 392   g_blacklist_initialized = NT_SUCCESS(ret);
 393
 394   // Mark the thunk storage as executable and prevent any future writes to it.
 395   page_executable = page_executable && VirtualProtect(&g_thunk_storage,
 396                                                       sizeof(g_thunk_storage),
 397                                                       PAGE_EXECUTE_READ,
 398                                                       &old_protect);
 399
 400   AddDllsFromRegistryToBlacklist();
 401
 402   return NT_SUCCESS(ret) && page_executable;
 403 }
 404
 405 void AddDllsFromRegistryToBlacklist() {
 406   HKEY key = NULL;
 407   LONG result = ::RegOpenKeyEx(HKEY_CURRENT_USER,
 408                                kRegistryFinchListPath,
 409                                0,
 410                                KEY_QUERY_VALUE | KEY_SET_VALUE,
 411                                &key);
 412
 413   if (result != ERROR_SUCCESS)
 414     return;
 415
 416   // We add dlls from the registry to the blacklist.
 417   DWORD value_len;
 418   DWORD name_len = MAX_PATH;
 419   std::vector<wchar_t> name_buffer(name_len);
 420   for (int i = 0; result == ERROR_SUCCESS; ++i) {
 421     name_len = MAX_PATH;
 422     value_len = 0;
 423     result = ::RegEnumValue(
 424         key, i, &name_buffer[0], &name_len, NULL, NULL, NULL, &value_len);
 425     if (result != ERROR_SUCCESS)
 426       break;
 427
 428     name_len = name_len + 1;
 429     value_len = value_len + 1;
 430     std::vector<wchar_t> value_buffer(value_len);
 431     result = ::RegEnumValue(key, i, &name_buffer[0], &name_len, NULL, NULL,
 432                             reinterpret_cast<BYTE*>(&value_buffer[0]),
 433                             &value_len);
 434     if (result != ERROR_SUCCESS)
 435       break;
 436     value_buffer[value_len - 1] = L'\0';
 437     AddDllToBlacklist(&value_buffer[0]);
 438   }
 439
 440   ::RegCloseKey(key);
 441   return;
 442 }
 443
 444 }  // namespace blacklist