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1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. | 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 | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 | 4 |
5 #include "sandbox/win/src/handle_closer_agent.h" | 5 #include "sandbox/win/src/handle_closer_agent.h" |
6 | 6 |
7 #include "base/logging.h" | 7 #include "base/logging.h" |
8 #include "sandbox/win/src/nt_internals.h" | 8 #include "sandbox/win/src/nt_internals.h" |
9 #include "sandbox/win/src/win_utils.h" | 9 #include "sandbox/win/src/win_utils.h" |
10 | 10 |
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34 | 34 |
35 namespace sandbox { | 35 namespace sandbox { |
36 | 36 |
37 // Memory buffer mapped from the parent, with the list of handles. | 37 // Memory buffer mapped from the parent, with the list of handles. |
38 SANDBOX_INTERCEPT HandleCloserInfo* g_handles_to_close = NULL; | 38 SANDBOX_INTERCEPT HandleCloserInfo* g_handles_to_close = NULL; |
39 | 39 |
40 bool HandleCloserAgent::NeedsHandlesClosed() { | 40 bool HandleCloserAgent::NeedsHandlesClosed() { |
41 return g_handles_to_close != NULL; | 41 return g_handles_to_close != NULL; |
42 } | 42 } |
43 | 43 |
| 44 HandleCloserAgent::HandleCloserAgent() |
| 45 : dummy_handle_(::CreateEvent(NULL, FALSE, FALSE, NULL)) { |
| 46 } |
| 47 |
| 48 // Attempts to stuff |closed_handle| with a duplicated handle for a dummy Event |
| 49 // with no access. This should allow the handle to be closed, to avoid |
| 50 // generating EXCEPTION_INVALID_HANDLE on shutdown, but nothing else. For now |
| 51 // the only supported |type| is Event or File. |
| 52 bool HandleCloserAgent::AttemptToStuffHandleSlot(HANDLE closed_handle, |
| 53 const base::string16& type) { |
| 54 // Only attempt to stuff Files and Events at the moment. |
| 55 if (type != L"Event" && type != L"File") { |
| 56 return true; |
| 57 } |
| 58 |
| 59 if (!dummy_handle_.IsValid()) |
| 60 return false; |
| 61 |
| 62 // This should never happen, as g_dummy is created before closing to_stuff. |
| 63 DCHECK(dummy_handle_.Get() != closed_handle); |
| 64 |
| 65 std::vector<HANDLE> to_close; |
| 66 HANDLE dup_dummy = NULL; |
| 67 size_t count = 16; |
| 68 |
| 69 do { |
| 70 if (!::DuplicateHandle(::GetCurrentProcess(), dummy_handle_.Get(), |
| 71 ::GetCurrentProcess(), &dup_dummy, 0, FALSE, 0)) |
| 72 break; |
| 73 if (dup_dummy != closed_handle) |
| 74 to_close.push_back(dup_dummy); |
| 75 } while (count-- && |
| 76 reinterpret_cast<uintptr_t>(dup_dummy) < |
| 77 reinterpret_cast<uintptr_t>(closed_handle)); |
| 78 |
| 79 for (auto h : to_close) |
| 80 ::CloseHandle(h); |
| 81 |
| 82 // Useful to know when we're not able to stuff handles. |
| 83 DCHECK(dup_dummy == closed_handle); |
| 84 |
| 85 return dup_dummy == closed_handle; |
| 86 } |
| 87 |
44 // Reads g_handles_to_close and creates the lookup map. | 88 // Reads g_handles_to_close and creates the lookup map. |
45 void HandleCloserAgent::InitializeHandlesToClose() { | 89 void HandleCloserAgent::InitializeHandlesToClose() { |
46 CHECK(g_handles_to_close != NULL); | 90 CHECK(g_handles_to_close != NULL); |
47 | 91 |
48 // Grab the header. | 92 // Grab the header. |
49 HandleListEntry* entry = g_handles_to_close->handle_entries; | 93 HandleListEntry* entry = g_handles_to_close->handle_entries; |
50 for (size_t i = 0; i < g_handles_to_close->num_handle_types; ++i) { | 94 for (size_t i = 0; i < g_handles_to_close->num_handle_types; ++i) { |
51 // Set the type name. | 95 // Set the type name. |
52 base::char16* input = entry->handle_type; | 96 base::char16* input = entry->handle_type; |
53 HandleMap::mapped_type& handle_names = handles_to_close_[input]; | 97 HandleMap::mapped_type& handle_names = handles_to_close_[input]; |
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129 if (!names.empty()) { | 173 if (!names.empty()) { |
130 // Move on to the next handle if this name doesn't match. | 174 // Move on to the next handle if this name doesn't match. |
131 if (!GetHandleName(handle, &handle_name) || !names.count(handle_name)) | 175 if (!GetHandleName(handle, &handle_name) || !names.count(handle_name)) |
132 continue; | 176 continue; |
133 } | 177 } |
134 | 178 |
135 if (!::SetHandleInformation(handle, HANDLE_FLAG_PROTECT_FROM_CLOSE, 0)) | 179 if (!::SetHandleInformation(handle, HANDLE_FLAG_PROTECT_FROM_CLOSE, 0)) |
136 return false; | 180 return false; |
137 if (!::CloseHandle(handle)) | 181 if (!::CloseHandle(handle)) |
138 return false; | 182 return false; |
| 183 // Attempt to stuff this handle with a new dummy Event. |
| 184 AttemptToStuffHandleSlot(handle, result->first); |
139 } | 185 } |
140 } | 186 } |
141 | 187 |
142 return true; | 188 return true; |
143 } | 189 } |
144 | 190 |
145 } // namespace sandbox | 191 } // namespace sandbox |
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