sandbox/win/src/sandbox_nt_util.cc

   1 // Copyright (c) 2012 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 "sandbox/win/src/sandbox_nt_util.h"
   6
   7 #include "base/win/pe_image.h"
   8 #include "sandbox/win/src/sandbox_factory.h"
   9 #include "sandbox/win/src/target_services.h"
  10
  11 namespace sandbox {
  12
  13 // This is the list of all imported symbols from ntdll.dll.
  14 SANDBOX_INTERCEPT NtExports g_nt;
  15
  16 }  // namespace sandbox
  17
  18 namespace {
  19
  20 #if defined(_WIN64)
  21 void* AllocateNearTo(void* source, size_t size) {
  22   using sandbox::g_nt;
  23
  24   // Start with 1 GB above the source.
  25   const size_t kOneGB = 0x40000000;
  26   void* base = reinterpret_cast<char*>(source) + kOneGB;
  27   SIZE_T actual_size = size;
  28   ULONG_PTR zero_bits = 0;  // Not the correct type if used.
  29   ULONG type = MEM_RESERVE;
  30
  31   NTSTATUS ret;
  32   int attempts = 0;
  33   for (; attempts < 41; attempts++) {
  34     ret = g_nt.AllocateVirtualMemory(NtCurrentProcess, &base, zero_bits,
  35                                      &actual_size, type, PAGE_READWRITE);
  36     if (NT_SUCCESS(ret)) {
  37       if (base < source ||
  38           base >= reinterpret_cast<char*>(source) + 4 * kOneGB) {
  39         // We won't be able to patch this dll.
  40         VERIFY_SUCCESS(g_nt.FreeVirtualMemory(NtCurrentProcess, &base, &size,
  41                                               MEM_RELEASE));
  42         return NULL;
  43       }
  44       break;
  45     }
  46
  47     if (attempts == 30) {
  48       // Try the first GB.
  49       base = reinterpret_cast<char*>(source);
  50     } else if (attempts == 40) {
  51       // Try the highest available address.
  52       base = NULL;
  53       type |= MEM_TOP_DOWN;
  54     }
  55
  56     // Try 100 MB higher.
  57     base = reinterpret_cast<char*>(base) + 100 * 0x100000;
  58   };
  59
  60   if (attempts == 41)
  61     return NULL;
  62
  63   ret = g_nt.AllocateVirtualMemory(NtCurrentProcess, &base, zero_bits,
  64                                    &actual_size, MEM_COMMIT, PAGE_READWRITE);
  65
  66   if (!NT_SUCCESS(ret)) {
  67     VERIFY_SUCCESS(g_nt.FreeVirtualMemory(NtCurrentProcess, &base, &size,
  68                                           MEM_RELEASE));
  69     base = NULL;
  70   }
  71
  72   return base;
  73 }
  74 #else  // defined(_WIN64).
  75 void* AllocateNearTo(void* source, size_t size) {
  76   using sandbox::g_nt;
  77   UNREFERENCED_PARAMETER(source);
  78
  79   // In 32-bit processes allocations below 512k are predictable, so mark
  80   // anything in that range as reserved and retry until we get a good address.
  81   const void* const kMinAddress = reinterpret_cast<void*>(512 * 1024);
  82   NTSTATUS ret;
  83   SIZE_T actual_size;
  84   void* base;
  85   do {
  86     base = NULL;
  87     actual_size = 64 * 1024;
  88     ret = g_nt.AllocateVirtualMemory(NtCurrentProcess, &base, 0, &actual_size,
  89                                      MEM_RESERVE, PAGE_NOACCESS);
  90     if (!NT_SUCCESS(ret))
  91       return NULL;
  92   } while (base < kMinAddress);
  93
  94   actual_size = size;
  95   ret = g_nt.AllocateVirtualMemory(NtCurrentProcess, &base, 0, &actual_size,
  96                                    MEM_COMMIT, PAGE_READWRITE);
  97   if (!NT_SUCCESS(ret))
  98     return NULL;
  99   return base;
 100 }
 101 #endif  // defined(_WIN64).
 102
 103 }  // namespace.
 104
 105 namespace sandbox {
 106
 107 // Handle for our private heap.
 108 void* g_heap = NULL;
 109
 110 SANDBOX_INTERCEPT HANDLE g_shared_section;
 111 SANDBOX_INTERCEPT size_t g_shared_IPC_size = 0;
 112 SANDBOX_INTERCEPT size_t g_shared_policy_size = 0;
 113
 114 void* volatile g_shared_policy_memory = NULL;
 115 void* volatile g_shared_IPC_memory = NULL;
 116
 117 // Both the IPC and the policy share a single region of memory in which the IPC
 118 // memory is first and the policy memory is last.
 119 bool MapGlobalMemory() {
 120   if (NULL == g_shared_IPC_memory) {
 121     void* memory = NULL;
 122     SIZE_T size = 0;
 123     // Map the entire shared section from the start.
 124     NTSTATUS ret = g_nt.MapViewOfSection(g_shared_section, NtCurrentProcess,
 125                                          &memory, 0, 0, NULL, &size, ViewUnmap,
 126                                          0, PAGE_READWRITE);
 127
 128     if (!NT_SUCCESS(ret) || NULL == memory) {
 129       NOTREACHED_NT();
 130       return false;
 131     }
 132
 133     if (NULL != _InterlockedCompareExchangePointer(&g_shared_IPC_memory,
 134                                                    memory, NULL)) {
 135         // Somebody beat us to the memory setup.
 136         ret = g_nt.UnmapViewOfSection(NtCurrentProcess, memory);
 137         VERIFY_SUCCESS(ret);
 138     }
 139     DCHECK_NT(g_shared_IPC_size > 0);
 140     g_shared_policy_memory = reinterpret_cast<char*>(g_shared_IPC_memory)
 141                              + g_shared_IPC_size;
 142   }
 143   DCHECK_NT(g_shared_policy_memory);
 144   DCHECK_NT(g_shared_policy_size > 0);
 145   return true;
 146 }
 147
 148 void* GetGlobalIPCMemory() {
 149   if (!MapGlobalMemory())
 150     return NULL;
 151   return g_shared_IPC_memory;
 152 }
 153
 154 void* GetGlobalPolicyMemory() {
 155   if (!MapGlobalMemory())
 156     return NULL;
 157   return g_shared_policy_memory;
 158 }
 159
 160 bool InitHeap() {
 161   if (!g_heap) {
 162     // Create a new heap using default values for everything.
 163     void* heap = g_nt.RtlCreateHeap(HEAP_GROWABLE, NULL, 0, 0, NULL, NULL);
 164     if (!heap)
 165       return false;
 166
 167     if (NULL != _InterlockedCompareExchangePointer(&g_heap, heap, NULL)) {
 168       // Somebody beat us to the memory setup.
 169       g_nt.RtlDestroyHeap(heap);
 170     }
 171   }
 172   return (g_heap != NULL);
 173 }
 174
 175 // Physically reads or writes from memory to verify that (at this time), it is
 176 // valid. Returns a dummy value.
 177 int TouchMemory(void* buffer, size_t size_bytes, RequiredAccess intent) {
 178   const int kPageSize = 4096;
 179   int dummy = 0;
 180   char* start = reinterpret_cast<char*>(buffer);
 181   char* end = start + size_bytes - 1;
 182
 183   if (WRITE == intent) {
 184     for (; start < end; start += kPageSize) {
 185       *start = 0;
 186     }
 187     *end = 0;
 188   } else {
 189     for (; start < end; start += kPageSize) {
 190       dummy += *start;
 191     }
 192     dummy += *end;
 193   }
 194
 195   return dummy;
 196 }
 197
 198 bool ValidParameter(void* buffer, size_t size, RequiredAccess intent) {
 199   DCHECK_NT(size);
 200   __try {
 201     TouchMemory(buffer, size, intent);
 202   } __except(EXCEPTION_EXECUTE_HANDLER) {
 203     return false;
 204   }
 205   return true;
 206 }
 207
 208 NTSTATUS CopyData(void* destination, const void* source, size_t bytes) {
 209   NTSTATUS ret = STATUS_SUCCESS;
 210   __try {
 211     g_nt.memcpy(destination, source, bytes);
 212   } __except(EXCEPTION_EXECUTE_HANDLER) {
 213     ret = GetExceptionCode();
 214   }
 215   return ret;
 216 }
 217
 218 // Hacky code... replace with AllocAndCopyObjectAttributes.
 219 NTSTATUS AllocAndCopyName(const OBJECT_ATTRIBUTES* in_object,
 220                           wchar_t** out_name, uint32* attributes,
 221                           HANDLE* root) {
 222   if (!InitHeap())
 223     return STATUS_NO_MEMORY;
 224
 225   DCHECK_NT(out_name);
 226   *out_name = NULL;
 227   NTSTATUS ret = STATUS_UNSUCCESSFUL;
 228   __try {
 229     do {
 230       if (in_object->RootDirectory != static_cast<HANDLE>(0) && !root)
 231         break;
 232       if (NULL == in_object->ObjectName)
 233         break;
 234       if (NULL == in_object->ObjectName->Buffer)
 235         break;
 236
 237       size_t size = in_object->ObjectName->Length + sizeof(wchar_t);
 238       *out_name = new(NT_ALLOC) wchar_t[size/sizeof(wchar_t)];
 239       if (NULL == *out_name)
 240         break;
 241
 242       ret = CopyData(*out_name, in_object->ObjectName->Buffer,
 243                      size - sizeof(wchar_t));
 244       if (!NT_SUCCESS(ret))
 245         break;
 246
 247       (*out_name)[size / sizeof(wchar_t) - 1] = L'\0';
 248
 249       if (attributes)
 250         *attributes = in_object->Attributes;
 251
 252       if (root)
 253         *root = in_object->RootDirectory;
 254       ret = STATUS_SUCCESS;
 255     } while (false);
 256   } __except(EXCEPTION_EXECUTE_HANDLER) {
 257     ret = GetExceptionCode();
 258   }
 259
 260   if (!NT_SUCCESS(ret) && *out_name) {
 261     operator delete(*out_name, NT_ALLOC);
 262     *out_name = NULL;
 263   }
 264
 265   return ret;
 266 }
 267
 268 NTSTATUS GetProcessId(HANDLE process, ULONG *process_id) {
 269   PROCESS_BASIC_INFORMATION proc_info;
 270   ULONG bytes_returned;
 271
 272   NTSTATUS ret = g_nt.QueryInformationProcess(process, ProcessBasicInformation,
 273                                               &proc_info, sizeof(proc_info),
 274                                               &bytes_returned);
 275   if (!NT_SUCCESS(ret) || sizeof(proc_info) != bytes_returned)
 276     return ret;
 277
 278   *process_id = proc_info.UniqueProcessId;
 279   return STATUS_SUCCESS;
 280 }
 281
 282 bool IsSameProcess(HANDLE process) {
 283   if (NtCurrentProcess == process)
 284     return true;
 285
 286   static ULONG s_process_id = 0;
 287
 288   if (!s_process_id) {
 289     NTSTATUS ret = GetProcessId(NtCurrentProcess, &s_process_id);
 290     if (!NT_SUCCESS(ret))
 291       return false;
 292   }
 293
 294   ULONG process_id;
 295   NTSTATUS ret = GetProcessId(process, &process_id);
 296   if (!NT_SUCCESS(ret))
 297     return false;
 298
 299   return (process_id == s_process_id);
 300 }
 301
 302 bool IsValidImageSection(HANDLE section, PVOID *base, PLARGE_INTEGER offset,
 303                          PSIZE_T view_size) {
 304   if (!section || !base || !view_size || offset)
 305     return false;
 306
 307   HANDLE query_section;
 308
 309   NTSTATUS ret = g_nt.DuplicateObject(NtCurrentProcess, section,
 310                                       NtCurrentProcess, &query_section,
 311                                       SECTION_QUERY, 0, 0);
 312   if (!NT_SUCCESS(ret))
 313     return false;
 314
 315   SECTION_BASIC_INFORMATION basic_info;
 316   SIZE_T bytes_returned;
 317   ret = g_nt.QuerySection(query_section, SectionBasicInformation, &basic_info,
 318                           sizeof(basic_info), &bytes_returned);
 319
 320   VERIFY_SUCCESS(g_nt.Close(query_section));
 321
 322   if (!NT_SUCCESS(ret) || sizeof(basic_info) != bytes_returned)
 323     return false;
 324
 325   if (!(basic_info.Attributes & SEC_IMAGE))
 326     return false;
 327
 328   return true;
 329 }
 330
 331 UNICODE_STRING* AnsiToUnicode(const char* string) {
 332   ANSI_STRING ansi_string;
 333   ansi_string.Length = static_cast<USHORT>(g_nt.strlen(string));
 334   ansi_string.MaximumLength = ansi_string.Length + 1;
 335   ansi_string.Buffer = const_cast<char*>(string);
 336
 337   if (ansi_string.Length > ansi_string.MaximumLength)
 338     return NULL;
 339
 340   size_t name_bytes = ansi_string.MaximumLength * sizeof(wchar_t) +
 341                       sizeof(UNICODE_STRING);
 342
 343   UNICODE_STRING* out_string = reinterpret_cast<UNICODE_STRING*>(
 344                                    new(NT_ALLOC) char[name_bytes]);
 345   if (!out_string)
 346     return NULL;
 347
 348   out_string->MaximumLength = ansi_string.MaximumLength *  sizeof(wchar_t);
 349   out_string->Buffer = reinterpret_cast<wchar_t*>(&out_string[1]);
 350
 351   BOOLEAN alloc_destination = FALSE;
 352   NTSTATUS ret = g_nt.RtlAnsiStringToUnicodeString(out_string, &ansi_string,
 353                                                    alloc_destination);
 354   DCHECK_NT(STATUS_BUFFER_OVERFLOW != ret);
 355   if (!NT_SUCCESS(ret)) {
 356     operator delete(out_string, NT_ALLOC);
 357     return NULL;
 358   }
 359
 360   return out_string;
 361 }
 362
 363 UNICODE_STRING* GetImageInfoFromModule(HMODULE module, uint32* flags) {
 364   // PEImage's dtor won't be run during SEH unwinding, but that's OK.
 365 #pragma warning(push)
 366 #pragma warning(disable: 4509)
 367   UNICODE_STRING* out_name = NULL;
 368   __try {
 369     do {
 370       *flags = 0;
 371       base::win::PEImage pe(module);
 372
 373       if (!pe.VerifyMagic())
 374         break;
 375       *flags |= MODULE_IS_PE_IMAGE;
 376
 377       PIMAGE_EXPORT_DIRECTORY exports = pe.GetExportDirectory();
 378       if (exports) {
 379         char* name = reinterpret_cast<char*>(pe.RVAToAddr(exports->Name));
 380         out_name = AnsiToUnicode(name);
 381       }
 382
 383       PIMAGE_NT_HEADERS headers = pe.GetNTHeaders();
 384       if (headers) {
 385         if (headers->OptionalHeader.AddressOfEntryPoint)
 386           *flags |= MODULE_HAS_ENTRY_POINT;
 387         if (headers->OptionalHeader.SizeOfCode)
 388           *flags |= MODULE_HAS_CODE;
 389       }
 390     } while (false);
 391   } __except(EXCEPTION_EXECUTE_HANDLER) {
 392   }
 393
 394   return out_name;
 395 #pragma warning(pop)
 396 }
 397
 398 UNICODE_STRING* GetBackingFilePath(PVOID address) {
 399   // We'll start with something close to max_path charactes for the name.
 400   ULONG buffer_bytes = MAX_PATH * 2;
 401
 402   for (;;) {
 403     MEMORY_SECTION_NAME* section_name = reinterpret_cast<MEMORY_SECTION_NAME*>(
 404         new(NT_ALLOC) char[buffer_bytes]);
 405
 406     if (!section_name)
 407       return NULL;
 408
 409     ULONG returned_bytes;
 410     NTSTATUS ret = g_nt.QueryVirtualMemory(NtCurrentProcess, address,
 411                                            MemorySectionName, section_name,
 412                                            buffer_bytes, &returned_bytes);
 413
 414     if (STATUS_BUFFER_OVERFLOW == ret) {
 415       // Retry the call with the given buffer size.
 416       operator delete(section_name, NT_ALLOC);
 417       section_name = NULL;
 418       buffer_bytes = returned_bytes;
 419       continue;
 420     }
 421     if (!NT_SUCCESS(ret)) {
 422       operator delete(section_name, NT_ALLOC);
 423       return NULL;
 424     }
 425
 426     return reinterpret_cast<UNICODE_STRING*>(section_name);
 427   }
 428 }
 429
 430 UNICODE_STRING* ExtractModuleName(const UNICODE_STRING* module_path) {
 431   if ((!module_path) || (!module_path->Buffer))
 432     return NULL;
 433
 434   wchar_t* sep = NULL;
 435   int start_pos = module_path->Length / sizeof(wchar_t) - 1;
 436   int ix = start_pos;
 437
 438   for (; ix >= 0; --ix) {
 439     if (module_path->Buffer[ix] == L'\\') {
 440       sep = &module_path->Buffer[ix];
 441       break;
 442     }
 443   }
 444
 445   // Ends with path separator. Not a valid module name.
 446   if ((ix == start_pos) && sep)
 447     return NULL;
 448
 449   // No path separator found. Use the entire name.
 450   if (!sep) {
 451     sep = &module_path->Buffer[-1];
 452   }
 453
 454   // Add one to the size so we can null terminate the string.
 455   size_t size_bytes = (start_pos - ix + 1) * sizeof(wchar_t);
 456
 457   // Based on the code above, size_bytes should always be small enough
 458   // to make the static_cast below safe.
 459   DCHECK_NT(kuint16max > size_bytes);
 460   char* str_buffer = new(NT_ALLOC) char[size_bytes + sizeof(UNICODE_STRING)];
 461   if (!str_buffer)
 462     return NULL;
 463
 464   UNICODE_STRING* out_string = reinterpret_cast<UNICODE_STRING*>(str_buffer);
 465   out_string->Buffer = reinterpret_cast<wchar_t*>(&out_string[1]);
 466   out_string->Length = static_cast<USHORT>(size_bytes - sizeof(wchar_t));
 467   out_string->MaximumLength = static_cast<USHORT>(size_bytes);
 468
 469   NTSTATUS ret = CopyData(out_string->Buffer, &sep[1], out_string->Length);
 470   if (!NT_SUCCESS(ret)) {
 471     operator delete(out_string, NT_ALLOC);
 472     return NULL;
 473   }
 474
 475   out_string->Buffer[out_string->Length / sizeof(wchar_t)] = L'\0';
 476   return out_string;
 477 }
 478
 479 NTSTATUS AutoProtectMemory::ChangeProtection(void* address, size_t bytes,
 480                                              ULONG protect) {
 481   DCHECK_NT(!changed_);
 482   SIZE_T new_bytes = bytes;
 483   NTSTATUS ret = g_nt.ProtectVirtualMemory(NtCurrentProcess, &address,
 484                                            &new_bytes, protect, &old_protect_);
 485   if (NT_SUCCESS(ret)) {
 486     changed_ = true;
 487     address_ = address;
 488     bytes_ = new_bytes;
 489   }
 490
 491   return ret;
 492 }
 493
 494 NTSTATUS AutoProtectMemory::RevertProtection() {
 495   if (!changed_)
 496     return STATUS_SUCCESS;
 497
 498   DCHECK_NT(address_);
 499   DCHECK_NT(bytes_);
 500
 501   SIZE_T new_bytes = bytes_;
 502   NTSTATUS ret = g_nt.ProtectVirtualMemory(NtCurrentProcess, &address_,
 503                                            &new_bytes, old_protect_,
 504                                            &old_protect_);
 505   DCHECK_NT(NT_SUCCESS(ret));
 506
 507   changed_ = false;
 508   address_ = NULL;
 509   bytes_ = 0;
 510   old_protect_ = 0;
 511
 512   return ret;
 513 }
 514
 515 bool IsSupportedRenameCall(FILE_RENAME_INFORMATION* file_info, DWORD length,
 516                            uint32 file_info_class) {
 517   if (FileRenameInformation != file_info_class)
 518     return false;
 519
 520   if (length < sizeof(FILE_RENAME_INFORMATION))
 521     return false;
 522
 523   // Make sure file name length doesn't exceed the message length
 524   if (length - offsetof(FILE_RENAME_INFORMATION, FileName) <
 525       file_info->FileNameLength)
 526     return false;
 527
 528   // We don't support a root directory.
 529   if (file_info->RootDirectory)
 530     return false;
 531
 532   static const wchar_t kPathPrefix[] = { L'\\', L'?', L'?', L'\\'};
 533
 534   // Check if it starts with \\??\\. We don't support relative paths.
 535   if (file_info->FileNameLength < sizeof(kPathPrefix) ||
 536       file_info->FileNameLength > kuint16max)
 537     return false;
 538
 539   if (file_info->FileName[0] != kPathPrefix[0] ||
 540       file_info->FileName[1] != kPathPrefix[1] ||
 541       file_info->FileName[2] != kPathPrefix[2] ||
 542       file_info->FileName[3] != kPathPrefix[3])
 543     return false;
 544
 545   return true;
 546 }
 547
 548 }  // namespace sandbox
 549
 550 void* operator new(size_t size, sandbox::AllocationType type,
 551                    void* near_to) {
 552   using namespace sandbox;
 553
 554   void* result = NULL;
 555   if (NT_ALLOC == type) {
 556     if (InitHeap()) {
 557       // Use default flags for the allocation.
 558       result = g_nt.RtlAllocateHeap(sandbox::g_heap, 0, size);
 559     }
 560   } else if (NT_PAGE == type) {
 561     result = AllocateNearTo(near_to, size);
 562   } else {
 563     NOTREACHED_NT();
 564   }
 565
 566   // TODO: Returning NULL from operator new has undefined behavior, but
 567   // the Allocate() functions called above can return NULL. Consider checking
 568   // for NULL here and crashing or throwing.
 569
 570   return result;
 571 }
 572
 573 void operator delete(void* memory, sandbox::AllocationType type) {
 574   using namespace sandbox;
 575
 576   if (NT_ALLOC == type) {
 577     // Use default flags.
 578     VERIFY(g_nt.RtlFreeHeap(sandbox::g_heap, 0, memory));
 579   } else if (NT_PAGE == type) {
 580     void* base = memory;
 581     SIZE_T size = 0;
 582     VERIFY_SUCCESS(g_nt.FreeVirtualMemory(NtCurrentProcess, &base, &size,
 583                                           MEM_RELEASE));
 584   } else {
 585     NOTREACHED_NT();
 586   }
 587 }
 588
 589 void operator delete(void* memory, sandbox::AllocationType type,
 590                      void* near_to) {
 591   UNREFERENCED_PARAMETER(near_to);
 592   operator delete(memory, type);
 593 }
 594
 595 void* __cdecl operator new(size_t size, void* buffer,
 596                            sandbox::AllocationType type) {
 597   UNREFERENCED_PARAMETER(size);
 598   UNREFERENCED_PARAMETER(type);
 599   return buffer;
 600 }
 601
 602 void __cdecl operator delete(void* memory, void* buffer,
 603                              sandbox::AllocationType type) {
 604   UNREFERENCED_PARAMETER(memory);
 605   UNREFERENCED_PARAMETER(buffer);
 606   UNREFERENCED_PARAMETER(type);
 607 }