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Issue 623883002: Revert "Move mojo edk into mojo/edk" (Closed) Base URL: https://chromium.googlesource.com/chromium/src.git@master
Patch Set: Created 6 years, 2 months ago
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1 // Copyright 2014 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 "mojo/edk/system/transport_data.h"
6
7 #include <string.h>
8
9 #include "base/compiler_specific.h"
10 #include "base/logging.h"
11 #include "mojo/edk/system/channel.h"
12 #include "mojo/edk/system/constants.h"
13 #include "mojo/edk/system/message_in_transit.h"
14
15 namespace mojo {
16 namespace system {
17
18 // The maximum amount of space needed per platform handle.
19 // (|{Channel,RawChannel}::GetSerializedPlatformHandleSize()| should always
20 // return a value which is at most this. This is only used to calculate
21 // |TransportData::kMaxBufferSize|. This value should be a multiple of the
22 // alignment in order to simplify calculations, even though the actual amount of
23 // space needed need not be a multiple of the alignment.
24 const size_t kMaxSizePerPlatformHandle = 8;
25 static_assert(kMaxSizePerPlatformHandle % MessageInTransit::kMessageAlignment ==
26 0,
27 "kMaxSizePerPlatformHandle not a multiple of alignment");
28
29 STATIC_CONST_MEMBER_DEFINITION const size_t
30 TransportData::kMaxSerializedDispatcherSize;
31 STATIC_CONST_MEMBER_DEFINITION const size_t
32 TransportData::kMaxSerializedDispatcherPlatformHandles;
33
34 // static
35 const size_t TransportData::kMaxPlatformHandles =
36 kMaxMessageNumHandles * kMaxSerializedDispatcherPlatformHandles;
37
38 // In additional to the header, for each attached (Mojo) handle there'll be a
39 // handle table entry and serialized dispatcher data.
40 // Note: This definition must follow the one for |kMaxPlatformHandles|;
41 // otherwise, we get a static initializer with gcc (but not clang).
42 // static
43 const size_t TransportData::kMaxBufferSize =
44 sizeof(Header) +
45 kMaxMessageNumHandles *
46 (sizeof(HandleTableEntry) + kMaxSerializedDispatcherSize) +
47 kMaxPlatformHandles * kMaxSizePerPlatformHandle;
48
49 struct TransportData::PrivateStructForCompileAsserts {
50 static_assert(sizeof(Header) % MessageInTransit::kMessageAlignment == 0,
51 "sizeof(MessageInTransit::Header) not a multiple of alignment");
52 static_assert(kMaxSerializedDispatcherSize %
53 MessageInTransit::kMessageAlignment ==
54 0,
55 "kMaxSerializedDispatcherSize not a multiple of alignment");
56 static_assert(sizeof(HandleTableEntry) %
57 MessageInTransit::kMessageAlignment ==
58 0,
59 "sizeof(MessageInTransit::HandleTableEntry) not a multiple of "
60 "alignment");
61 };
62
63 TransportData::TransportData(scoped_ptr<DispatcherVector> dispatchers,
64 Channel* channel) {
65 DCHECK(dispatchers);
66 DCHECK(channel);
67
68 const size_t num_handles = dispatchers->size();
69 DCHECK_GT(num_handles, 0u);
70
71 // The offset to the start of the (Mojo) handle table.
72 const size_t handle_table_start_offset = sizeof(Header);
73 // The offset to the start of the serialized dispatcher data.
74 const size_t serialized_dispatcher_start_offset =
75 handle_table_start_offset + num_handles * sizeof(HandleTableEntry);
76 // The estimated size of the secondary buffer. We compute this estimate below.
77 // It must be at least as big as the (eventual) actual size.
78 size_t estimated_size = serialized_dispatcher_start_offset;
79 size_t estimated_num_platform_handles = 0;
80 #if DCHECK_IS_ON
81 std::vector<size_t> all_max_sizes(num_handles);
82 std::vector<size_t> all_max_platform_handles(num_handles);
83 #endif
84 for (size_t i = 0; i < num_handles; i++) {
85 if (Dispatcher* dispatcher = (*dispatchers)[i].get()) {
86 size_t max_size = 0;
87 size_t max_platform_handles = 0;
88 Dispatcher::TransportDataAccess::StartSerialize(
89 dispatcher, channel, &max_size, &max_platform_handles);
90
91 DCHECK_LE(max_size, kMaxSerializedDispatcherSize);
92 estimated_size += MessageInTransit::RoundUpMessageAlignment(max_size);
93 DCHECK_LE(estimated_size, kMaxBufferSize);
94
95 DCHECK_LE(max_platform_handles, kMaxSerializedDispatcherPlatformHandles);
96 estimated_num_platform_handles += max_platform_handles;
97 DCHECK_LE(estimated_num_platform_handles, kMaxPlatformHandles);
98
99 #if DCHECK_IS_ON
100 all_max_sizes[i] = max_size;
101 all_max_platform_handles[i] = max_platform_handles;
102 #endif
103 }
104 }
105
106 size_t size_per_platform_handle = 0;
107 if (estimated_num_platform_handles > 0) {
108 size_per_platform_handle = channel->GetSerializedPlatformHandleSize();
109 DCHECK_LE(size_per_platform_handle, kMaxSizePerPlatformHandle);
110 estimated_size += estimated_num_platform_handles * size_per_platform_handle;
111 estimated_size = MessageInTransit::RoundUpMessageAlignment(estimated_size);
112 DCHECK_LE(estimated_size, kMaxBufferSize);
113 }
114
115 buffer_.reset(static_cast<char*>(
116 base::AlignedAlloc(estimated_size, MessageInTransit::kMessageAlignment)));
117 // Entirely clear out the secondary buffer, since then we won't have to worry
118 // about clearing padding or unused space (e.g., if a dispatcher fails to
119 // serialize).
120 memset(buffer_.get(), 0, estimated_size);
121
122 if (estimated_num_platform_handles > 0) {
123 DCHECK(!platform_handles_);
124 platform_handles_.reset(new embedder::PlatformHandleVector());
125 }
126
127 Header* header = reinterpret_cast<Header*>(buffer_.get());
128 header->num_handles = static_cast<uint32_t>(num_handles);
129 // (Okay to leave |platform_handle_table_offset|, |num_platform_handles|, and
130 // |unused| be zero; we'll set the former two later if necessary.)
131
132 HandleTableEntry* handle_table = reinterpret_cast<HandleTableEntry*>(
133 buffer_.get() + handle_table_start_offset);
134 size_t current_offset = serialized_dispatcher_start_offset;
135 for (size_t i = 0; i < num_handles; i++) {
136 Dispatcher* dispatcher = (*dispatchers)[i].get();
137 if (!dispatcher) {
138 static_assert(Dispatcher::kTypeUnknown == 0,
139 "Value of Dispatcher::kTypeUnknown must be 0");
140 continue;
141 }
142
143 #if DCHECK_IS_ON
144 size_t old_platform_handles_size =
145 platform_handles_ ? platform_handles_->size() : 0;
146 #endif
147
148 void* destination = buffer_.get() + current_offset;
149 size_t actual_size = 0;
150 if (Dispatcher::TransportDataAccess::EndSerializeAndClose(
151 dispatcher,
152 channel,
153 destination,
154 &actual_size,
155 platform_handles_.get())) {
156 handle_table[i].type = static_cast<int32_t>(dispatcher->GetType());
157 handle_table[i].offset = static_cast<uint32_t>(current_offset);
158 handle_table[i].size = static_cast<uint32_t>(actual_size);
159 // (Okay to not set |unused| since we cleared the entire buffer.)
160
161 #if DCHECK_IS_ON
162 DCHECK_LE(actual_size, all_max_sizes[i]);
163 DCHECK_LE(platform_handles_
164 ? (platform_handles_->size() - old_platform_handles_size)
165 : 0,
166 all_max_platform_handles[i]);
167 #endif
168 } else {
169 // Nothing to do on failure, since |buffer_| was cleared, and
170 // |kTypeUnknown| is zero. The handle was simply closed.
171 LOG(ERROR) << "Failed to serialize handle to remote message pipe";
172 }
173
174 current_offset += MessageInTransit::RoundUpMessageAlignment(actual_size);
175 DCHECK_LE(current_offset, estimated_size);
176 DCHECK_LE(platform_handles_ ? platform_handles_->size() : 0,
177 estimated_num_platform_handles);
178 }
179
180 if (platform_handles_ && platform_handles_->size() > 0) {
181 header->platform_handle_table_offset =
182 static_cast<uint32_t>(current_offset);
183 header->num_platform_handles =
184 static_cast<uint32_t>(platform_handles_->size());
185 current_offset += platform_handles_->size() * size_per_platform_handle;
186 current_offset = MessageInTransit::RoundUpMessageAlignment(current_offset);
187 }
188
189 // There's no aligned realloc, so it's no good way to release unused space (if
190 // we overshot our estimated space requirements).
191 buffer_size_ = current_offset;
192
193 // |dispatchers_| will be destroyed as it goes out of scope.
194 }
195
196 #if defined(OS_POSIX)
197 TransportData::TransportData(
198 embedder::ScopedPlatformHandleVectorPtr platform_handles)
199 : buffer_size_(sizeof(Header)), platform_handles_(platform_handles.Pass()) {
200 buffer_.reset(static_cast<char*>(
201 base::AlignedAlloc(buffer_size_, MessageInTransit::kMessageAlignment)));
202 memset(buffer_.get(), 0, buffer_size_);
203 }
204 #endif // defined(OS_POSIX)
205
206 TransportData::~TransportData() {
207 }
208
209 // static
210 const char* TransportData::ValidateBuffer(
211 size_t serialized_platform_handle_size,
212 const void* buffer,
213 size_t buffer_size) {
214 DCHECK(buffer);
215 DCHECK_GT(buffer_size, 0u);
216
217 // Always make sure that the buffer size is sane; if it's not, someone's
218 // messing with us.
219 if (buffer_size < sizeof(Header) || buffer_size > kMaxBufferSize ||
220 buffer_size % MessageInTransit::kMessageAlignment != 0)
221 return "Invalid message secondary buffer size";
222
223 const Header* header = static_cast<const Header*>(buffer);
224 const size_t num_handles = header->num_handles;
225
226 #if !defined(OS_POSIX)
227 // On POSIX, we send control messages with platform handles (but no handles)
228 // attached (see the comments for
229 // |TransportData(embedder::ScopedPlatformHandleVectorPtr)|. (This check isn't
230 // important security-wise anyway.)
231 if (num_handles == 0)
232 return "Message has no handles attached, but secondary buffer present";
233 #endif
234
235 // Sanity-check |num_handles| (before multiplying it against anything).
236 if (num_handles > kMaxMessageNumHandles)
237 return "Message handle payload too large";
238
239 if (buffer_size < sizeof(Header) + num_handles * sizeof(HandleTableEntry))
240 return "Message secondary buffer too small";
241
242 if (header->num_platform_handles == 0) {
243 // Then |platform_handle_table_offset| should also be zero.
244 if (header->platform_handle_table_offset != 0) {
245 return "Message has no handles attached, but platform handle table "
246 "present";
247 }
248 } else {
249 // |num_handles| has already been validated, so the multiplication is okay.
250 if (header->num_platform_handles >
251 num_handles * kMaxSerializedDispatcherPlatformHandles)
252 return "Message has too many platform handles attached";
253
254 static const char kInvalidPlatformHandleTableOffset[] =
255 "Message has invalid platform handle table offset";
256 // This doesn't check that the platform handle table doesn't alias other
257 // stuff, but it doesn't matter, since it's all read-only.
258 if (header->platform_handle_table_offset %
259 MessageInTransit::kMessageAlignment !=
260 0)
261 return kInvalidPlatformHandleTableOffset;
262
263 // ">" instead of ">=" since the size per handle may be zero.
264 if (header->platform_handle_table_offset > buffer_size)
265 return kInvalidPlatformHandleTableOffset;
266
267 // We already checked |platform_handle_table_offset| and
268 // |num_platform_handles|, so the addition and multiplication are okay.
269 if (header->platform_handle_table_offset +
270 header->num_platform_handles * serialized_platform_handle_size >
271 buffer_size)
272 return kInvalidPlatformHandleTableOffset;
273 }
274
275 const HandleTableEntry* handle_table =
276 reinterpret_cast<const HandleTableEntry*>(
277 static_cast<const char*>(buffer) + sizeof(Header));
278 static const char kInvalidSerializedDispatcher[] =
279 "Message contains invalid serialized dispatcher";
280 for (size_t i = 0; i < num_handles; i++) {
281 size_t offset = handle_table[i].offset;
282 if (offset % MessageInTransit::kMessageAlignment != 0)
283 return kInvalidSerializedDispatcher;
284
285 size_t size = handle_table[i].size;
286 if (size > kMaxSerializedDispatcherSize || size > buffer_size)
287 return kInvalidSerializedDispatcher;
288
289 // Note: This is an overflow-safe check for |offset + size > buffer_size|
290 // (we know that |size <= buffer_size| from the previous check).
291 if (offset > buffer_size - size)
292 return kInvalidSerializedDispatcher;
293 }
294
295 return nullptr;
296 }
297
298 // static
299 void TransportData::GetPlatformHandleTable(const void* transport_data_buffer,
300 size_t* num_platform_handles,
301 const void** platform_handle_table) {
302 DCHECK(transport_data_buffer);
303 DCHECK(num_platform_handles);
304 DCHECK(platform_handle_table);
305
306 const Header* header = static_cast<const Header*>(transport_data_buffer);
307 *num_platform_handles = header->num_platform_handles;
308 *platform_handle_table = static_cast<const char*>(transport_data_buffer) +
309 header->platform_handle_table_offset;
310 }
311
312 // static
313 scoped_ptr<DispatcherVector> TransportData::DeserializeDispatchers(
314 const void* buffer,
315 size_t buffer_size,
316 embedder::ScopedPlatformHandleVectorPtr platform_handles,
317 Channel* channel) {
318 DCHECK(buffer);
319 DCHECK_GT(buffer_size, 0u);
320 DCHECK(channel);
321
322 const Header* header = static_cast<const Header*>(buffer);
323 const size_t num_handles = header->num_handles;
324 scoped_ptr<DispatcherVector> dispatchers(new DispatcherVector(num_handles));
325
326 const HandleTableEntry* handle_table =
327 reinterpret_cast<const HandleTableEntry*>(
328 static_cast<const char*>(buffer) + sizeof(Header));
329 for (size_t i = 0; i < num_handles; i++) {
330 size_t offset = handle_table[i].offset;
331 size_t size = handle_table[i].size;
332 // Should already have been checked by |ValidateBuffer()|:
333 DCHECK_EQ(offset % MessageInTransit::kMessageAlignment, 0u);
334 DCHECK_LE(offset, buffer_size);
335 DCHECK_LE(offset + size, buffer_size);
336
337 const void* source = static_cast<const char*>(buffer) + offset;
338 (*dispatchers)[i] = Dispatcher::TransportDataAccess::Deserialize(
339 channel, handle_table[i].type, source, size, platform_handles.get());
340 }
341
342 return dispatchers.Pass();
343 }
344
345 } // namespace system
346 } // namespace mojo
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