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 #if defined(_WIN64)
  30   // We have two thunks, in order: the return path and the forward path.
  31   if (!SetInternalThunk(thunk_storage, storage_bytes, NULL, target_))
  32     return STATUS_BUFFER_TOO_SMALL;
  33
  34   size_t thunk_bytes = GetInternalThunkSize();
  35   storage_bytes -= thunk_bytes;
  36   thunk_storage = reinterpret_cast<char*>(thunk_storage) + thunk_bytes;
  37 #endif
  38
  39   if (!SetInternalThunk(thunk_storage, storage_bytes, target_, interceptor_))
  40     return STATUS_BUFFER_TOO_SMALL;
  41
  42   AutoProtectMemory memory;
  43   ret = memory.ChangeProtection(eat_entry_, sizeof(DWORD), PAGE_READWRITE);
  44   if (!NT_SUCCESS(ret))
  45     return ret;
  46
  47   // Perform the patch.
  48 #pragma warning(push)
  49 #pragma warning(disable: 4311)
  50   // These casts generate warnings because they are 32 bit specific.
  51   *eat_entry_ = reinterpret_cast<DWORD>(thunk_storage) -
  52                 reinterpret_cast<DWORD>(target_module);
  53 #pragma warning(pop)
  54
  55   if (NULL != storage_used)
  56     *storage_used = GetThunkSize();
  57
  58   return ret;
  59 }
  60
  61 NTSTATUS EatResolverThunk::ResolveTarget(const void* module,
  62                                          const char* function_name,
  63                                          void** address) {
  64   DCHECK_NT(address);
  65   if (!module)
  66     return STATUS_INVALID_PARAMETER;
  67
  68   base::win::PEImage pe(module);
  69   if (!pe.VerifyMagic())
  70     return STATUS_INVALID_IMAGE_FORMAT;
  71
  72   eat_entry_ = pe.GetExportEntry(function_name);
  73
  74   if (!eat_entry_)
  75     return STATUS_PROCEDURE_NOT_FOUND;
  76
  77   *address = pe.RVAToAddr(*eat_entry_);
  78
  79   return STATUS_SUCCESS;
  80 }
  81
  82 size_t EatResolverThunk::GetThunkSize() const {
  83 #if defined(_WIN64)
  84   return GetInternalThunkSize() * 2;
  85 #else
  86   return GetInternalThunkSize();
  87 #endif
  88 }
  89
  90 }  // namespace sandbox