sandbox/win/src/eat_resolver.cc

   1 // Copyright (c) 2006-2010 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/eat_resolver.h"
   6
   7 #include "base/win/pe_image.h"
   8 #include "sandbox/win/src/sandbox_nt_util.h"
   9
  10 namespace sandbox {
  11
  12 NTSTATUS EatResolverThunk::Setup(const void* target_module,
  13                                  const void* interceptor_module,
  14                                  const char* target_name,
  15                                  const char* interceptor_name,
  16                                  const void* interceptor_entry_point,
  17                                  void* thunk_storage,
  18                                  size_t storage_bytes,
  19                                  size_t* storage_used) {
  20   NTSTATUS ret = Init(target_module, interceptor_module, target_name,
  21                       interceptor_name, interceptor_entry_point,
  22                       thunk_storage, storage_bytes);
  23   if (!NT_SUCCESS(ret))
  24     return ret;
  25
  26   if (!eat_entry_)
  27     return STATUS_INVALID_PARAMETER;
  28
  29   size_t thunk_bytes = GetInternalThunkSize();
  30
  31 #if defined(_WIN64)
  32   // We have two thunks, in order: the return path and the forward path.
  33   if (!SetInternalThunk(thunk_storage, storage_bytes, NULL, target_))
  34     return STATUS_BUFFER_TOO_SMALL;
  35
  36   storage_bytes -= thunk_bytes;
  37   thunk_storage = reinterpret_cast<char*>(thunk_storage) + thunk_bytes;
  38 #endif
  39
  40   if (!SetInternalThunk(thunk_storage, storage_bytes, target_, interceptor_))
  41     return STATUS_BUFFER_TOO_SMALL;
  42
  43   AutoProtectMemory memory;
  44   ret = memory.ChangeProtection(eat_entry_, sizeof(DWORD), PAGE_READWRITE);
  45   if (!NT_SUCCESS(ret))
  46     return ret;
  47
  48   // Perform the patch.
  49 #pragma warning(push)
  50 #pragma warning(disable: 4311)
  51   // These casts generate warnings because they are 32 bit specific.
  52   *eat_entry_ = reinterpret_cast<DWORD>(thunk_storage) -
  53                 reinterpret_cast<DWORD>(target_module);
  54 #pragma warning(pop)
  55
  56   if (NULL != storage_used)
  57     *storage_used = GetThunkSize();
  58
  59   return ret;
  60 }
  61
  62 NTSTATUS EatResolverThunk::ResolveTarget(const void* module,
  63                                          const char* function_name,
  64                                          void** address) {
  65   DCHECK_NT(address);
  66   if (!module)
  67     return STATUS_INVALID_PARAMETER;
  68
  69   base::win::PEImage pe(module);
  70   if (!pe.VerifyMagic())
  71     return STATUS_INVALID_IMAGE_FORMAT;
  72
  73   eat_entry_ = pe.GetExportEntry(function_name);
  74
  75   if (!eat_entry_)
  76     return STATUS_PROCEDURE_NOT_FOUND;
  77
  78   *address = pe.RVAToAddr(*eat_entry_);
  79
  80   return STATUS_SUCCESS;
  81 }
  82
  83 size_t EatResolverThunk::GetThunkSize() const {
  84 #if defined(_WIN64)
  85   return GetInternalThunkSize() * 2;
  86 #else
  87   return GetInternalThunkSize();
  88 #endif
  89 }
  90
  91 }  // namespace sandbox