chrome_elf/blacklist/blacklist_interceptions.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 // Implementation of NtMapViewOfSection intercept for 32 bit builds.
   6 //
   7 // TODO(robertshield): Implement the 64 bit intercept.
   8
   9 #include "chrome_elf/blacklist/blacklist_interceptions.h"
  10
  11 #include <string>
  12 #include <vector>
  13
  14 // Note that only #includes from base that are either header-only or built into
  15 // base_static (see base/base.gyp) are allowed here.
  16 #include "base/basictypes.h"
  17 #include "base/strings/string16.h"
  18 #include "base/win/pe_image.h"
  19 #include "chrome_elf/blacklist/blacklist.h"
  20 #include "chrome_elf/breakpad.h"
  21 #include "sandbox/win/src/internal_types.h"
  22 #include "sandbox/win/src/nt_internals.h"
  23 #include "sandbox/win/src/sandbox_nt_util.h"
  24 #include "sandbox/win/src/sandbox_types.h"
  25
  26 namespace {
  27
  28 NtQuerySectionFunction g_nt_query_section_func = NULL;
  29 NtQueryVirtualMemoryFunction g_nt_query_virtual_memory_func = NULL;
  30 NtUnmapViewOfSectionFunction g_nt_unmap_view_of_section_func = NULL;
  31
  32 // TODO(robertshield): Merge with ntdll exports cache.
  33 FARPROC GetNtDllExportByName(const char* export_name) {
  34   HMODULE ntdll = ::GetModuleHandle(sandbox::kNtdllName);
  35   return ::GetProcAddress(ntdll, export_name);
  36 }
  37
  38 int DllMatch(const base::string16& module_name) {
  39   for (int i = 0; blacklist::g_troublesome_dlls[i] != NULL; ++i) {
  40     if (_wcsicmp(module_name.c_str(), blacklist::g_troublesome_dlls[i]) == 0)
  41       return i;
  42   }
  43   return -1;
  44 }
  45
  46 // TODO(robertshield): Some of the helper functions below overlap somewhat with
  47 // code in sandbox_nt_util.cc. See if they can be unified.
  48
  49 // Native reimplementation of PSAPIs GetMappedFileName.
  50 base::string16 GetBackingModuleFilePath(PVOID address) {
  51   DCHECK_NT(g_nt_query_virtual_memory_func);
  52
  53   // We'll start with something close to max_path characters for the name.
  54   SIZE_T buffer_bytes = MAX_PATH * 2;
  55   std::vector<BYTE> buffer_data(buffer_bytes);
  56
  57   for (;;) {
  58     MEMORY_SECTION_NAME* section_name =
  59         reinterpret_cast<MEMORY_SECTION_NAME*>(&buffer_data[0]);
  60
  61     if (!section_name)
  62       break;
  63
  64     SIZE_T returned_bytes;
  65     NTSTATUS ret = g_nt_query_virtual_memory_func(
  66         NtCurrentProcess, address, MemorySectionName, section_name,
  67         buffer_bytes, &returned_bytes);
  68
  69     if (STATUS_BUFFER_OVERFLOW == ret) {
  70       // Retry the call with the given buffer size.
  71       buffer_bytes = returned_bytes + 1;
  72       buffer_data.resize(buffer_bytes);
  73       section_name = NULL;
  74       continue;
  75     }
  76     if (!NT_SUCCESS(ret))
  77       break;
  78
  79     UNICODE_STRING* section_string =
  80         reinterpret_cast<UNICODE_STRING*>(section_name);
  81     return base::string16(section_string->Buffer,
  82                           section_string->Length / sizeof(wchar_t));
  83   }
  84
  85   return base::string16();
  86 }
  87
  88 bool IsModuleValidImageSection(HANDLE section,
  89                                PVOID *base,
  90                                PLARGE_INTEGER offset,
  91                                PSIZE_T view_size) {
  92   DCHECK_NT(g_nt_query_section_func);
  93
  94   if (!section || !base || !view_size || offset)
  95     return false;
  96
  97   SECTION_BASIC_INFORMATION basic_info;
  98   SIZE_T bytes_returned;
  99   NTSTATUS ret = g_nt_query_section_func(section, SectionBasicInformation,
 100                                          &basic_info, sizeof(basic_info),
 101                                          &bytes_returned);
 102
 103   if (!NT_SUCCESS(ret) || sizeof(basic_info) != bytes_returned)
 104     return false;
 105
 106   if (!(basic_info.Attributes & SEC_IMAGE))
 107     return false;
 108
 109   return true;
 110 }
 111
 112 base::string16 ExtractLoadedModuleName(const base::string16& module_path) {
 113   if (module_path.empty() || module_path[module_path.size() - 1] == L'\\')
 114     return base::string16();
 115
 116   size_t sep = module_path.find_last_of(L'\\');
 117   if (sep == base::string16::npos)
 118     return module_path;
 119   else
 120     return module_path.substr(sep+1);
 121 }
 122
 123 // Fills |out_name| with the image name from the given |pe| image and |flags|
 124 // with additional info about the image.
 125 void SafeGetImageInfo(const base::win::PEImage& pe,
 126                       std::string* out_name,
 127                       uint32* flags) {
 128   out_name->clear();
 129   out_name->reserve(MAX_PATH);
 130   *flags = 0;
 131   __try {
 132     if (pe.VerifyMagic()) {
 133       *flags |= sandbox::MODULE_IS_PE_IMAGE;
 134
 135       PIMAGE_EXPORT_DIRECTORY exports = pe.GetExportDirectory();
 136       if (exports) {
 137         const char* image_name = reinterpret_cast<const char*>(
 138             pe.RVAToAddr(exports->Name));
 139         size_t i = 0;
 140         for (; i < MAX_PATH && *image_name; ++i, ++image_name)
 141           out_name->push_back(*image_name);
 142       }
 143
 144       PIMAGE_NT_HEADERS headers = pe.GetNTHeaders();
 145       if (headers) {
 146         if (headers->OptionalHeader.AddressOfEntryPoint)
 147           *flags |= sandbox::MODULE_HAS_ENTRY_POINT;
 148         if (headers->OptionalHeader.SizeOfCode)
 149           *flags |= sandbox::MODULE_HAS_CODE;
 150       }
 151     }
 152   } __except((GetExceptionCode() == EXCEPTION_ACCESS_VIOLATION ||
 153               GetExceptionCode() == EXCEPTION_GUARD_PAGE ||
 154               GetExceptionCode() == EXCEPTION_IN_PAGE_ERROR) ?
 155              EXCEPTION_EXECUTE_HANDLER : EXCEPTION_CONTINUE_SEARCH) {
 156     out_name->clear();
 157   }
 158 }
 159
 160 base::string16 GetImageInfoFromLoadedModule(HMODULE module, uint32* flags) {
 161   std::string out_name;
 162   base::win::PEImage pe(module);
 163   SafeGetImageInfo(pe, &out_name, flags);
 164   return base::string16(out_name.begin(), out_name.end());
 165 }
 166
 167 bool IsSameAsCurrentProcess(HANDLE process) {
 168   return  (NtCurrentProcess == process) ||
 169           (::GetProcessId(process) == ::GetCurrentProcessId());
 170 }
 171
 172 NTSTATUS BlNtMapViewOfSectionImpl(
 173     NtMapViewOfSectionFunction orig_MapViewOfSection,
 174     HANDLE section,
 175     HANDLE process,
 176     PVOID *base,
 177     ULONG_PTR zero_bits,
 178     SIZE_T commit_size,
 179     PLARGE_INTEGER offset,
 180     PSIZE_T view_size,
 181     SECTION_INHERIT inherit,
 182     ULONG allocation_type,
 183     ULONG protect) {
 184   NTSTATUS ret = orig_MapViewOfSection(section, process, base, zero_bits,
 185                                        commit_size, offset, view_size, inherit,
 186                                        allocation_type, protect);
 187
 188   if (!NT_SUCCESS(ret) || !IsSameAsCurrentProcess(process) ||
 189       !IsModuleValidImageSection(section, base, offset, view_size)) {
 190     return ret;
 191   }
 192
 193   HMODULE module = reinterpret_cast<HMODULE>(*base);
 194   if (module) {
 195     UINT image_flags;
 196
 197     base::string16 module_name(GetImageInfoFromLoadedModule(
 198         reinterpret_cast<HMODULE>(*base), &image_flags));
 199     base::string16 file_name(GetBackingModuleFilePath(*base));
 200
 201     if (module_name.empty() && (image_flags & sandbox::MODULE_HAS_CODE)) {
 202       // If the module has no exports we retrieve the module name from the
 203       // full path of the mapped section.
 204       module_name = ExtractLoadedModuleName(file_name);
 205     }
 206
 207     if (!module_name.empty()) {
 208       int blocked_index = DllMatch(module_name);
 209       if (blocked_index != -1) {
 210         DCHECK_NT(g_nt_unmap_view_of_section_func);
 211         g_nt_unmap_view_of_section_func(process, *base);
 212         ret = STATUS_UNSUCCESSFUL;
 213
 214         blacklist::BlockedDll(blocked_index);
 215       }
 216     }
 217   }
 218
 219   return ret;
 220 }
 221
 222 }  // namespace
 223
 224 namespace blacklist {
 225
 226 bool InitializeInterceptImports() {
 227   g_nt_query_section_func =
 228       reinterpret_cast<NtQuerySectionFunction>(
 229           GetNtDllExportByName("NtQuerySection"));
 230   g_nt_query_virtual_memory_func =
 231       reinterpret_cast<NtQueryVirtualMemoryFunction>(
 232           GetNtDllExportByName("NtQueryVirtualMemory"));
 233   g_nt_unmap_view_of_section_func =
 234       reinterpret_cast<NtUnmapViewOfSectionFunction>(
 235           GetNtDllExportByName("NtUnmapViewOfSection"));
 236
 237   return (g_nt_query_section_func && g_nt_query_virtual_memory_func &&
 238           g_nt_unmap_view_of_section_func);
 239 }
 240
 241 SANDBOX_INTERCEPT NTSTATUS WINAPI BlNtMapViewOfSection(
 242     NtMapViewOfSectionFunction orig_MapViewOfSection,
 243     HANDLE section,
 244     HANDLE process,
 245     PVOID *base,
 246     ULONG_PTR zero_bits,
 247     SIZE_T commit_size,
 248     PLARGE_INTEGER offset,
 249     PSIZE_T view_size,
 250     SECTION_INHERIT inherit,
 251     ULONG allocation_type,
 252     ULONG protect) {
 253   NTSTATUS ret = STATUS_UNSUCCESSFUL;
 254
 255   __try {
 256     ret = BlNtMapViewOfSectionImpl(orig_MapViewOfSection, section, process,
 257                                    base, zero_bits, commit_size, offset,
 258                                    view_size, inherit, allocation_type,
 259                                    protect);
 260   } __except(GenerateCrashDump(GetExceptionInformation())) {
 261   }
 262
 263   return ret;
 264 }
 265
 266 #if defined(_WIN64)
 267 NTSTATUS WINAPI BlNtMapViewOfSection64(
 268     HANDLE section, HANDLE process, PVOID *base, ULONG_PTR zero_bits,
 269     SIZE_T commit_size, PLARGE_INTEGER offset, PSIZE_T view_size,
 270     SECTION_INHERIT inherit, ULONG allocation_type, ULONG protect) {
 271   return BlNtMapViewOfSection(g_nt_map_view_of_section_func, section, process,
 272                               base, zero_bits, commit_size, offset, view_size,
 273                               inherit, allocation_type, protect);
 274 }
 275 #endif
 276 }  // namespace blacklist