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
3 // found in the LICENSE file.
4
5 #include "base/pickle.h"
6
7 #include <stdlib.h>
8
9 #include <algorithm> // for max()
10 #include <limits>
11
12 #include "base/bits.h"
13 #include "base/macros.h"
14 #include "base/numerics/safe_conversions.h"
15 #include "base/numerics/safe_math.h"
16 #include "build/build_config.h"
17
18 namespace base {
19
20 // static
21 const int Pickle::kPayloadUnit = 64;
22
23 static const size_t kCapacityReadOnly = static_cast<size_t>(-1);
24
PickleIterator(const Pickle & pickle)25 PickleIterator::PickleIterator(const Pickle& pickle)
26 : payload_(pickle.payload()),
27 read_index_(0),
28 end_index_(pickle.payload_size()) {
29 }
30
31 template <typename Type>
ReadBuiltinType(Type * result)32 inline bool PickleIterator::ReadBuiltinType(Type* result) {
33 const char* read_from = GetReadPointerAndAdvance<Type>();
34 if (!read_from)
35 return false;
36 if (sizeof(Type) > sizeof(uint32_t))
37 memcpy(result, read_from, sizeof(*result));
38 else
39 *result = *reinterpret_cast<const Type*>(read_from);
40 return true;
41 }
42
Advance(size_t size)43 inline void PickleIterator::Advance(size_t size) {
44 size_t aligned_size = bits::Align(size, sizeof(uint32_t));
45 if (end_index_ - read_index_ < aligned_size) {
46 read_index_ = end_index_;
47 } else {
48 read_index_ += aligned_size;
49 }
50 }
51
52 template<typename Type>
GetReadPointerAndAdvance()53 inline const char* PickleIterator::GetReadPointerAndAdvance() {
54 if (sizeof(Type) > end_index_ - read_index_) {
55 read_index_ = end_index_;
56 return nullptr;
57 }
58 const char* current_read_ptr = payload_ + read_index_;
59 Advance(sizeof(Type));
60 return current_read_ptr;
61 }
62
GetReadPointerAndAdvance(int num_bytes)63 const char* PickleIterator::GetReadPointerAndAdvance(int num_bytes) {
64 if (num_bytes < 0 ||
65 end_index_ - read_index_ < static_cast<size_t>(num_bytes)) {
66 read_index_ = end_index_;
67 return nullptr;
68 }
69 const char* current_read_ptr = payload_ + read_index_;
70 Advance(num_bytes);
71 return current_read_ptr;
72 }
73
GetReadPointerAndAdvance(int num_elements,size_t size_element)74 inline const char* PickleIterator::GetReadPointerAndAdvance(
75 int num_elements,
76 size_t size_element) {
77 // Check for int32_t overflow.
78 int num_bytes;
79 if (!CheckMul(num_elements, size_element).AssignIfValid(&num_bytes))
80 return nullptr;
81 return GetReadPointerAndAdvance(num_bytes);
82 }
83
ReadBool(bool * result)84 bool PickleIterator::ReadBool(bool* result) {
85 return ReadBuiltinType(result);
86 }
87
ReadInt(int * result)88 bool PickleIterator::ReadInt(int* result) {
89 return ReadBuiltinType(result);
90 }
91
ReadLong(long * result)92 bool PickleIterator::ReadLong(long* result) {
93 // Always read long as a 64-bit value to ensure compatibility between 32-bit
94 // and 64-bit processes.
95 int64_t result_int64 = 0;
96 if (!ReadBuiltinType(&result_int64))
97 return false;
98 // CHECK if the cast truncates the value so that we know to change this IPC
99 // parameter to use int64_t.
100 *result = base::checked_cast<long>(result_int64);
101 return true;
102 }
103
ReadUInt16(uint16_t * result)104 bool PickleIterator::ReadUInt16(uint16_t* result) {
105 return ReadBuiltinType(result);
106 }
107
ReadUInt32(uint32_t * result)108 bool PickleIterator::ReadUInt32(uint32_t* result) {
109 return ReadBuiltinType(result);
110 }
111
ReadInt64(int64_t * result)112 bool PickleIterator::ReadInt64(int64_t* result) {
113 return ReadBuiltinType(result);
114 }
115
ReadUInt64(uint64_t * result)116 bool PickleIterator::ReadUInt64(uint64_t* result) {
117 return ReadBuiltinType(result);
118 }
119
ReadFloat(float * result)120 bool PickleIterator::ReadFloat(float* result) {
121 // crbug.com/315213
122 // The source data may not be properly aligned, and unaligned float reads
123 // cause SIGBUS on some ARM platforms, so force using memcpy to copy the data
124 // into the result.
125 const char* read_from = GetReadPointerAndAdvance<float>();
126 if (!read_from)
127 return false;
128 memcpy(result, read_from, sizeof(*result));
129 return true;
130 }
131
ReadDouble(double * result)132 bool PickleIterator::ReadDouble(double* result) {
133 // crbug.com/315213
134 // The source data may not be properly aligned, and unaligned double reads
135 // cause SIGBUS on some ARM platforms, so force using memcpy to copy the data
136 // into the result.
137 const char* read_from = GetReadPointerAndAdvance<double>();
138 if (!read_from)
139 return false;
140 memcpy(result, read_from, sizeof(*result));
141 return true;
142 }
143
ReadString(std::string * result)144 bool PickleIterator::ReadString(std::string* result) {
145 int len;
146 if (!ReadInt(&len))
147 return false;
148 const char* read_from = GetReadPointerAndAdvance(len);
149 if (!read_from)
150 return false;
151
152 result->assign(read_from, len);
153 return true;
154 }
155
ReadStringPiece(StringPiece * result)156 bool PickleIterator::ReadStringPiece(StringPiece* result) {
157 int len;
158 if (!ReadInt(&len))
159 return false;
160 const char* read_from = GetReadPointerAndAdvance(len);
161 if (!read_from)
162 return false;
163
164 *result = StringPiece(read_from, len);
165 return true;
166 }
167
ReadString16(string16 * result)168 bool PickleIterator::ReadString16(string16* result) {
169 int len;
170 if (!ReadInt(&len))
171 return false;
172 const char* read_from = GetReadPointerAndAdvance(len, sizeof(char16));
173 if (!read_from)
174 return false;
175
176 result->assign(reinterpret_cast<const char16*>(read_from), len);
177 return true;
178 }
179
ReadStringPiece16(StringPiece16 * result)180 bool PickleIterator::ReadStringPiece16(StringPiece16* result) {
181 int len;
182 if (!ReadInt(&len))
183 return false;
184 const char* read_from = GetReadPointerAndAdvance(len, sizeof(char16));
185 if (!read_from)
186 return false;
187
188 *result = StringPiece16(reinterpret_cast<const char16*>(read_from), len);
189 return true;
190 }
191
ReadData(const char ** data,int * length)192 bool PickleIterator::ReadData(const char** data, int* length) {
193 *length = 0;
194 *data = nullptr;
195
196 if (!ReadInt(length))
197 return false;
198
199 return ReadBytes(data, *length);
200 }
201
ReadBytes(const char ** data,int length)202 bool PickleIterator::ReadBytes(const char** data, int length) {
203 const char* read_from = GetReadPointerAndAdvance(length);
204 if (!read_from)
205 return false;
206 *data = read_from;
207 return true;
208 }
209
210 Pickle::Attachment::Attachment() = default;
211
212 Pickle::Attachment::~Attachment() = default;
213
214 // Payload is uint32_t aligned.
215
Pickle()216 Pickle::Pickle()
217 : header_(nullptr),
218 header_size_(sizeof(Header)),
219 capacity_after_header_(0),
220 write_offset_(0) {
221 static_assert((Pickle::kPayloadUnit & (Pickle::kPayloadUnit - 1)) == 0,
222 "Pickle::kPayloadUnit must be a power of two");
223 Resize(kPayloadUnit);
224 header_->payload_size = 0;
225 }
226
Pickle(int header_size)227 Pickle::Pickle(int header_size)
228 : header_(nullptr),
229 header_size_(bits::Align(header_size, sizeof(uint32_t))),
230 capacity_after_header_(0),
231 write_offset_(0) {
232 DCHECK_GE(static_cast<size_t>(header_size), sizeof(Header));
233 DCHECK_LE(header_size, kPayloadUnit);
234 Resize(kPayloadUnit);
235 header_->payload_size = 0;
236 }
237
Pickle(const char * data,int data_len)238 Pickle::Pickle(const char* data, int data_len)
239 : header_(reinterpret_cast<Header*>(const_cast<char*>(data))),
240 header_size_(0),
241 capacity_after_header_(kCapacityReadOnly),
242 write_offset_(0) {
243 if (data_len >= static_cast<int>(sizeof(Header)))
244 header_size_ = data_len - header_->payload_size;
245
246 if (header_size_ > static_cast<unsigned int>(data_len))
247 header_size_ = 0;
248
249 if (header_size_ != bits::Align(header_size_, sizeof(uint32_t)))
250 header_size_ = 0;
251
252 // If there is anything wrong with the data, we're not going to use it.
253 if (!header_size_)
254 header_ = nullptr;
255 }
256
Pickle(const Pickle & other)257 Pickle::Pickle(const Pickle& other)
258 : header_(nullptr),
259 header_size_(other.header_size_),
260 capacity_after_header_(0),
261 write_offset_(other.write_offset_) {
262 Resize(other.header_->payload_size);
263 memcpy(header_, other.header_, header_size_ + other.header_->payload_size);
264 }
265
~Pickle()266 Pickle::~Pickle() {
267 if (capacity_after_header_ != kCapacityReadOnly)
268 free(header_);
269 }
270
operator =(const Pickle & other)271 Pickle& Pickle::operator=(const Pickle& other) {
272 if (this == &other) {
273 return *this;
274 }
275 if (capacity_after_header_ == kCapacityReadOnly) {
276 header_ = nullptr;
277 capacity_after_header_ = 0;
278 }
279 if (header_size_ != other.header_size_) {
280 free(header_);
281 header_ = nullptr;
282 header_size_ = other.header_size_;
283 }
284 Resize(other.header_->payload_size);
285 memcpy(header_, other.header_,
286 other.header_size_ + other.header_->payload_size);
287 write_offset_ = other.write_offset_;
288 return *this;
289 }
290
WriteString(const StringPiece & value)291 void Pickle::WriteString(const StringPiece& value) {
292 WriteInt(static_cast<int>(value.size()));
293 WriteBytes(value.data(), static_cast<int>(value.size()));
294 }
295
WriteString16(const StringPiece16 & value)296 void Pickle::WriteString16(const StringPiece16& value) {
297 WriteInt(static_cast<int>(value.size()));
298 WriteBytes(value.data(), static_cast<int>(value.size()) * sizeof(char16));
299 }
300
WriteData(const char * data,int length)301 void Pickle::WriteData(const char* data, int length) {
302 DCHECK_GE(length, 0);
303 WriteInt(length);
304 WriteBytes(data, length);
305 }
306
WriteBytes(const void * data,int length)307 void Pickle::WriteBytes(const void* data, int length) {
308 WriteBytesCommon(data, length);
309 }
310
Reserve(size_t length)311 void Pickle::Reserve(size_t length) {
312 size_t data_len = bits::Align(length, sizeof(uint32_t));
313 DCHECK_GE(data_len, length);
314 #ifdef ARCH_CPU_64_BITS
315 DCHECK_LE(data_len, std::numeric_limits<uint32_t>::max());
316 #endif
317 DCHECK_LE(write_offset_, std::numeric_limits<uint32_t>::max() - data_len);
318 size_t new_size = write_offset_ + data_len;
319 if (new_size > capacity_after_header_)
320 Resize(capacity_after_header_ * 2 + new_size);
321 }
322
WriteAttachment(scoped_refptr<Attachment> attachment)323 bool Pickle::WriteAttachment(scoped_refptr<Attachment> attachment) {
324 return false;
325 }
326
ReadAttachment(base::PickleIterator * iter,scoped_refptr<Attachment> * attachment) const327 bool Pickle::ReadAttachment(base::PickleIterator* iter,
328 scoped_refptr<Attachment>* attachment) const {
329 return false;
330 }
331
HasAttachments() const332 bool Pickle::HasAttachments() const {
333 return false;
334 }
335
Resize(size_t new_capacity)336 void Pickle::Resize(size_t new_capacity) {
337 CHECK_NE(capacity_after_header_, kCapacityReadOnly);
338 capacity_after_header_ = bits::Align(new_capacity, kPayloadUnit);
339 void* p = realloc(header_, GetTotalAllocatedSize());
340 CHECK(p);
341 header_ = reinterpret_cast<Header*>(p);
342 }
343
ClaimBytes(size_t num_bytes)344 void* Pickle::ClaimBytes(size_t num_bytes) {
345 void* p = ClaimUninitializedBytesInternal(num_bytes);
346 CHECK(p);
347 memset(p, 0, num_bytes);
348 return p;
349 }
350
GetTotalAllocatedSize() const351 size_t Pickle::GetTotalAllocatedSize() const {
352 if (capacity_after_header_ == kCapacityReadOnly)
353 return 0;
354 return header_size_ + capacity_after_header_;
355 }
356
357 // static
FindNext(size_t header_size,const char * start,const char * end)358 const char* Pickle::FindNext(size_t header_size,
359 const char* start,
360 const char* end) {
361 size_t pickle_size = 0;
362 if (!PeekNext(header_size, start, end, &pickle_size))
363 return nullptr;
364
365 if (pickle_size > static_cast<size_t>(end - start))
366 return nullptr;
367
368 return start + pickle_size;
369 }
370
371 // static
PeekNext(size_t header_size,const char * start,const char * end,size_t * pickle_size)372 bool Pickle::PeekNext(size_t header_size,
373 const char* start,
374 const char* end,
375 size_t* pickle_size) {
376 DCHECK_EQ(header_size, bits::Align(header_size, sizeof(uint32_t)));
377 DCHECK_GE(header_size, sizeof(Header));
378 DCHECK_LE(header_size, static_cast<size_t>(kPayloadUnit));
379
380 size_t length = static_cast<size_t>(end - start);
381 if (length < sizeof(Header))
382 return false;
383
384 const Header* hdr = reinterpret_cast<const Header*>(start);
385 if (length < header_size)
386 return false;
387
388 // If payload_size causes an overflow, we return maximum possible
389 // pickle size to indicate that.
390 *pickle_size = ClampAdd(header_size, hdr->payload_size);
391 return true;
392 }
393
WriteBytesStatic(const void * data)394 template <size_t length> void Pickle::WriteBytesStatic(const void* data) {
395 WriteBytesCommon(data, length);
396 }
397
398 template void Pickle::WriteBytesStatic<2>(const void* data);
399 template void Pickle::WriteBytesStatic<4>(const void* data);
400 template void Pickle::WriteBytesStatic<8>(const void* data);
401
ClaimUninitializedBytesInternal(size_t length)402 inline void* Pickle::ClaimUninitializedBytesInternal(size_t length) {
403 DCHECK_NE(kCapacityReadOnly, capacity_after_header_)
404 << "oops: pickle is readonly";
405 size_t data_len = bits::Align(length, sizeof(uint32_t));
406 DCHECK_GE(data_len, length);
407 #ifdef ARCH_CPU_64_BITS
408 DCHECK_LE(data_len, std::numeric_limits<uint32_t>::max());
409 #endif
410 DCHECK_LE(write_offset_, std::numeric_limits<uint32_t>::max() - data_len);
411 size_t new_size = write_offset_ + data_len;
412 if (new_size > capacity_after_header_) {
413 size_t new_capacity = capacity_after_header_ * 2;
414 const size_t kPickleHeapAlign = 4096;
415 if (new_capacity > kPickleHeapAlign)
416 new_capacity = bits::Align(new_capacity, kPickleHeapAlign) - kPayloadUnit;
417 Resize(std::max(new_capacity, new_size));
418 }
419
420 char* write = mutable_payload() + write_offset_;
421 memset(write + length, 0, data_len - length); // Always initialize padding
422 header_->payload_size = static_cast<uint32_t>(new_size);
423 write_offset_ = new_size;
424 return write;
425 }
426
WriteBytesCommon(const void * data,size_t length)427 inline void Pickle::WriteBytesCommon(const void* data, size_t length) {
428 DCHECK_NE(kCapacityReadOnly, capacity_after_header_)
429 << "oops: pickle is readonly";
430 MSAN_CHECK_MEM_IS_INITIALIZED(data, length);
431 void* write = ClaimUninitializedBytesInternal(length);
432 memcpy(write, data, length);
433 }
434
435 } // namespace base
436