sandbox/win/src/handle_closer.cc

   1 // Copyright (c) 2011 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/handle_closer.h"
   6
   7 #include "base/logging.h"
   8 #include "base/memory/scoped_ptr.h"
   9 #include "base/win/windows_version.h"
  10 #include "sandbox/win/src/interceptors.h"
  11 #include "sandbox/win/src/internal_types.h"
  12 #include "sandbox/win/src/nt_internals.h"
  13 #include "sandbox/win/src/process_thread_interception.h"
  14 #include "sandbox/win/src/win_utils.h"
  15
  16 namespace {
  17
  18 template<typename T> T RoundUpToWordSize(T v) {
  19   if (size_t mod = v % sizeof(size_t))
  20     v += sizeof(size_t) - mod;
  21   return v;
  22 }
  23
  24 template<typename T> T* RoundUpToWordSize(T* v) {
  25   return reinterpret_cast<T*>(RoundUpToWordSize(reinterpret_cast<size_t>(v)));
  26 }
  27
  28 }  // namespace
  29
  30 namespace sandbox {
  31
  32 // Memory buffer mapped from the parent, with the list of handles.
  33 SANDBOX_INTERCEPT HandleCloserInfo* g_handles_to_close;
  34
  35 HandleCloser::HandleCloser() {}
  36
  37 ResultCode HandleCloser::AddHandle(const base::char16* handle_type,
  38                                    const base::char16* handle_name) {
  39   if (!handle_type)
  40     return SBOX_ERROR_BAD_PARAMS;
  41
  42   base::string16 resolved_name;
  43   if (handle_name) {
  44     resolved_name = handle_name;
  45     if (handle_type == base::string16(L"Key"))
  46       if (!ResolveRegistryName(resolved_name, &resolved_name))
  47         return SBOX_ERROR_BAD_PARAMS;
  48   }
  49
  50   HandleMap::iterator names = handles_to_close_.find(handle_type);
  51   if (names == handles_to_close_.end()) {  // We have no entries for this type.
  52     std::pair<HandleMap::iterator, bool> result = handles_to_close_.insert(
  53         HandleMap::value_type(handle_type, HandleMap::mapped_type()));
  54     names = result.first;
  55     if (handle_name)
  56       names->second.insert(resolved_name);
  57   } else if (!handle_name) {  // Now we need to close all handles of this type.
  58     names->second.clear();
  59   } else if (!names->second.empty()) {  // Add another name for this type.
  60     names->second.insert(resolved_name);
  61   }  // If we're already closing all handles of type then we're done.
  62
  63   return SBOX_ALL_OK;
  64 }
  65
  66 size_t HandleCloser::GetBufferSize() {
  67   size_t bytes_total = offsetof(HandleCloserInfo, handle_entries);
  68
  69   for (HandleMap::iterator i = handles_to_close_.begin();
  70        i != handles_to_close_.end(); ++i) {
  71     size_t bytes_entry = offsetof(HandleListEntry, handle_type) +
  72         (i->first.size() + 1) * sizeof(base::char16);
  73     for (HandleMap::mapped_type::iterator j = i->second.begin();
  74          j != i->second.end(); ++j) {
  75       bytes_entry += ((*j).size() + 1) * sizeof(base::char16);
  76     }
  77
  78     // Round up to the nearest multiple of word size.
  79     bytes_entry = RoundUpToWordSize(bytes_entry);
  80     bytes_total += bytes_entry;
  81   }
  82
  83   return bytes_total;
  84 }
  85
  86 bool HandleCloser::InitializeTargetHandles(TargetProcess* target) {
  87   // Do nothing on an empty list (global pointer already initialized to NULL).
  88   if (handles_to_close_.empty())
  89     return true;
  90
  91   size_t bytes_needed = GetBufferSize();
  92   scoped_ptr<size_t[]> local_buffer(
  93       new size_t[bytes_needed / sizeof(size_t)]);
  94
  95   if (!SetupHandleList(local_buffer.get(), bytes_needed))
  96     return false;
  97
  98   HANDLE child = target->Process();
  99
 100   // Allocate memory in the target process without specifying the address
 101   void* remote_data = ::VirtualAllocEx(child, NULL, bytes_needed,
 102                                        MEM_COMMIT, PAGE_READWRITE);
 103   if (NULL == remote_data)
 104     return false;
 105
 106   // Copy the handle buffer over.
 107   SIZE_T bytes_written;
 108   BOOL result = ::WriteProcessMemory(child, remote_data, local_buffer.get(),
 109                                      bytes_needed, &bytes_written);
 110   if (!result || bytes_written != bytes_needed) {
 111     ::VirtualFreeEx(child, remote_data, 0, MEM_RELEASE);
 112     return false;
 113   }
 114
 115   g_handles_to_close = reinterpret_cast<HandleCloserInfo*>(remote_data);
 116
 117   ResultCode rc = target->TransferVariable("g_handles_to_close",
 118                                            &g_handles_to_close,
 119                                            sizeof(g_handles_to_close));
 120
 121   return (SBOX_ALL_OK == rc);
 122 }
 123
 124 bool HandleCloser::SetupHandleList(void* buffer, size_t buffer_bytes) {
 125   ::ZeroMemory(buffer, buffer_bytes);
 126   HandleCloserInfo* handle_info = reinterpret_cast<HandleCloserInfo*>(buffer);
 127   handle_info->record_bytes = buffer_bytes;
 128   handle_info->num_handle_types = handles_to_close_.size();
 129
 130   base::char16* output = reinterpret_cast<base::char16*>(
 131       &handle_info->handle_entries[0]);
 132   base::char16* end = reinterpret_cast<base::char16*>(
 133       reinterpret_cast<char*>(buffer) + buffer_bytes);
 134   for (HandleMap::iterator i = handles_to_close_.begin();
 135        i != handles_to_close_.end(); ++i) {
 136     if (output >= end)
 137       return false;
 138     HandleListEntry* list_entry = reinterpret_cast<HandleListEntry*>(output);
 139     output = &list_entry->handle_type[0];
 140
 141     // Copy the typename and set the offset and count.
 142     i->first._Copy_s(output, i->first.size(), i->first.size());
 143     *(output += i->first.size()) = L'\0';
 144     output++;
 145     list_entry->offset_to_names = reinterpret_cast<char*>(output) -
 146         reinterpret_cast<char*>(list_entry);
 147     list_entry->name_count = i->second.size();
 148
 149     // Copy the handle names.
 150     for (HandleMap::mapped_type::iterator j = i->second.begin();
 151          j != i->second.end(); ++j) {
 152       output = std::copy((*j).begin(), (*j).end(), output) + 1;
 153     }
 154
 155     // Round up to the nearest multiple of sizeof(size_t).
 156     output = RoundUpToWordSize(output);
 157     list_entry->record_bytes = reinterpret_cast<char*>(output) -
 158         reinterpret_cast<char*>(list_entry);
 159   }
 160
 161   DCHECK_EQ(reinterpret_cast<size_t>(output), reinterpret_cast<size_t>(end));
 162   return output <= end;
 163 }
 164
 165 bool GetHandleName(HANDLE handle, base::string16* handle_name) {
 166   static NtQueryObject QueryObject = NULL;
 167   if (!QueryObject)
 168     ResolveNTFunctionPtr("NtQueryObject", &QueryObject);
 169
 170   ULONG size = MAX_PATH;
 171   scoped_ptr<UNICODE_STRING, base::FreeDeleter> name;
 172   NTSTATUS result;
 173
 174   do {
 175     name.reset(static_cast<UNICODE_STRING*>(malloc(size)));
 176     DCHECK(name.get());
 177     result = QueryObject(handle, ObjectNameInformation, name.get(),
 178                          size, &size);
 179   } while (result == STATUS_INFO_LENGTH_MISMATCH ||
 180            result == STATUS_BUFFER_OVERFLOW);
 181
 182   if (NT_SUCCESS(result) && name->Buffer && name->Length)
 183     handle_name->assign(name->Buffer, name->Length / sizeof(wchar_t));
 184   else
 185     handle_name->clear();
 186
 187   return NT_SUCCESS(result);
 188 }
 189
 190 }  // namespace sandbox