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 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> 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 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> 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 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 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 84 bool PickleIterator::ReadBool(bool* result) { 85 return ReadBuiltinType(result); 86 } 87 88 bool PickleIterator::ReadInt(int* result) { 89 return ReadBuiltinType(result); 90 } 91 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 } 103 104 bool PickleIterator::ReadUInt16(uint16_t* result) { 105 return ReadBuiltinType(result); 106 } 107 108 bool PickleIterator::ReadUInt32(uint32_t* result) { 109 return ReadBuiltinType(result); 110 } 111 112 bool PickleIterator::ReadInt64(int64_t* result) { 113 return ReadBuiltinType(result); 114 } 115 116 bool PickleIterator::ReadUInt64(uint64_t* result) { 117 return ReadBuiltinType(result); 118 } 119 120 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 } 131 132 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 } 143 144 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 } 155 156 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 } 167 168 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 } 179 180 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 } 191 192 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 } 201 202 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. 215 216 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 } 226 227 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 } 237 238 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 } 256 257 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 } 265 266 Pickle::~Pickle() { 267 if (capacity_after_header_ != kCapacityReadOnly) 268 free(header_); 269 } 270 271 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 } 290 291 void Pickle::WriteString(const StringPiece& value) { 292 WriteInt(static_cast<int>(value.size())); 293 WriteBytes(value.data(), static_cast<int>(value.size())); 294 } 295 296 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 } 300 301 void Pickle::WriteData(const char* data, int length) { 302 DCHECK_GE(length, 0); 303 WriteInt(length); 304 WriteBytes(data, length); 305 } 306 307 void Pickle::WriteBytes(const void* data, int length) { 308 WriteBytesCommon(data, length); 309 } 310 311 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 } 322 323 bool Pickle::WriteAttachment(scoped_refptr<Attachment> attachment) { 324 return false; 325 } 326 327 bool Pickle::ReadAttachment(base::PickleIterator* iter, 328 scoped_refptr<Attachment>* attachment) const { 329 return false; 330 } 331 332 bool Pickle::HasAttachments() const { 333 return false; 334 } 335 336 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 } 343 344 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 } 350 351 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 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 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 } 393 394 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); 401 402 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 } 426 427 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
