base/pickle.cc

   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/numerics/safe_conversions.h"
  14 #include "base/numerics/safe_math.h"
  15 #include "build/build_config.h"
  16
  17 namespace base {
  18
  19 // static
  20 const int Pickle::kPayloadUnit = 64;
  21
  22 static const size_t kCapacityReadOnly = static_cast<size_t>(-1);
  23
  24 PickleIterator::PickleIterator(const Pickle& pickle)
  25     : payload_(pickle.payload()),
  26       read_index_(0),
  27       end_index_(pickle.payload_size()) {
  28 }
  29
  30 template <typename Type>
  31 inline bool PickleIterator::ReadBuiltinType(Type* result) {
  32   const char* read_from = GetReadPointerAndAdvance<Type>();
  33   if (!read_from)
  34     return false;
  35   if (sizeof(Type) > sizeof(uint32_t))
  36     memcpy(result, read_from, sizeof(*result));
  37   else
  38     *result = *reinterpret_cast<const Type*>(read_from);
  39   return true;
  40 }
  41
  42 inline void PickleIterator::Advance(size_t size) {
  43   size_t aligned_size = bits::AlignUp(size, sizeof(uint32_t));
  44   if (end_index_ - read_index_ < aligned_size) {
  45     read_index_ = end_index_;
  46   } else {
  47     read_index_ += aligned_size;
  48   }
  49 }
  50
  51 template<typename Type>
  52 inline const char* PickleIterator::GetReadPointerAndAdvance() {
  53   if (sizeof(Type) > end_index_ - read_index_) {
  54     read_index_ = end_index_;
  55     return nullptr;
  56   }
  57   const char* current_read_ptr = payload_ + read_index_;
  58   Advance(sizeof(Type));
  59   return current_read_ptr;
  60 }
  61
  62 const char* PickleIterator::GetReadPointerAndAdvance(int num_bytes) {
  63   if (num_bytes < 0 ||
  64       end_index_ - read_index_ < static_cast<size_t>(num_bytes)) {
  65     read_index_ = end_index_;
  66     return nullptr;
  67   }
  68   const char* current_read_ptr = payload_ + read_index_;
  69   Advance(num_bytes);
  70   return current_read_ptr;
  71 }
  72
  73 inline const char* PickleIterator::GetReadPointerAndAdvance(
  74     int num_elements,
  75     size_t size_element) {
  76   // Check for int32_t overflow.
  77   int num_bytes;
  78   if (!CheckMul(num_elements, size_element).AssignIfValid(&num_bytes))
  79     return nullptr;
  80   return GetReadPointerAndAdvance(num_bytes);
  81 }
  82
  83 bool PickleIterator::ReadBool(bool* result) {
  84   return ReadBuiltinType(result);
  85 }
  86
  87 bool PickleIterator::ReadInt(int* result) {
  88   return ReadBuiltinType(result);
  89 }
  90
  91 bool PickleIterator::ReadLong(long* result) {
  92   // Always read long as a 64-bit value to ensure compatibility between 32-bit
  93   // and 64-bit processes.
  94   int64_t result_int64 = 0;
  95   if (!ReadBuiltinType(&result_int64))
  96     return false;
  97   // CHECK if the cast truncates the value so that we know to change this IPC
  98   // parameter to use int64_t.
  99   *result = base::checked_cast<long>(result_int64);
 100   return true;
 101 }
 102
 103 bool PickleIterator::ReadUInt16(uint16_t* result) {
 104   return ReadBuiltinType(result);
 105 }
 106
 107 bool PickleIterator::ReadUInt32(uint32_t* result) {
 108   return ReadBuiltinType(result);
 109 }
 110
 111 bool PickleIterator::ReadInt64(int64_t* result) {
 112   return ReadBuiltinType(result);
 113 }
 114
 115 bool PickleIterator::ReadUInt64(uint64_t* result) {
 116   return ReadBuiltinType(result);
 117 }
 118
 119 bool PickleIterator::ReadFloat(float* result) {
 120   // crbug.com/315213
 121   // The source data may not be properly aligned, and unaligned float reads
 122   // cause SIGBUS on some ARM platforms, so force using memcpy to copy the data
 123   // into the result.
 124   const char* read_from = GetReadPointerAndAdvance<float>();
 125   if (!read_from)
 126     return false;
 127   memcpy(result, read_from, sizeof(*result));
 128   return true;
 129 }
 130
 131 bool PickleIterator::ReadDouble(double* result) {
 132   // crbug.com/315213
 133   // The source data may not be properly aligned, and unaligned double reads
 134   // cause SIGBUS on some ARM platforms, so force using memcpy to copy the data
 135   // into the result.
 136   const char* read_from = GetReadPointerAndAdvance<double>();
 137   if (!read_from)
 138     return false;
 139   memcpy(result, read_from, sizeof(*result));
 140   return true;
 141 }
 142
 143 bool PickleIterator::ReadString(std::string* result) {
 144   int len;
 145   if (!ReadInt(&len))
 146     return false;
 147   const char* read_from = GetReadPointerAndAdvance(len);
 148   if (!read_from)
 149     return false;
 150
 151   result->assign(read_from, len);
 152   return true;
 153 }
 154
 155 bool PickleIterator::ReadStringPiece(StringPiece* result) {
 156   int len;
 157   if (!ReadInt(&len))
 158     return false;
 159   const char* read_from = GetReadPointerAndAdvance(len);
 160   if (!read_from)
 161     return false;
 162
 163   *result = StringPiece(read_from, len);
 164   return true;
 165 }
 166
 167 bool PickleIterator::ReadString16(std::u16string* result) {
 168   int len;
 169   if (!ReadInt(&len))
 170     return false;
 171   const char* read_from = GetReadPointerAndAdvance(len, sizeof(char16_t));
 172   if (!read_from)
 173     return false;
 174
 175   result->assign(reinterpret_cast<const char16_t*>(read_from), len);
 176   return true;
 177 }
 178
 179 bool PickleIterator::ReadStringPiece16(StringPiece16* result) {
 180   int len;
 181   if (!ReadInt(&len))
 182     return false;
 183   const char* read_from = GetReadPointerAndAdvance(len, sizeof(char16_t));
 184   if (!read_from)
 185     return false;
 186
 187   *result = StringPiece16(reinterpret_cast<const char16_t*>(read_from), len);
 188   return true;
 189 }
 190
 191 bool PickleIterator::ReadData(const char** data, int* length) {
 192   *length = 0;
 193   *data = nullptr;
 194
 195   if (!ReadInt(length))
 196     return false;
 197
 198   return ReadBytes(data, *length);
 199 }
 200
 201 bool PickleIterator::ReadData(base::span<const uint8_t>* data) {
 202   const char* ptr;
 203   int length;
 204
 205   if (!ReadData(&ptr, &length))
 206     return false;
 207
 208   *data = base::as_bytes(base::make_span(ptr, length));
 209   return true;
 210 }
 211
 212 bool PickleIterator::ReadBytes(const char** data, int length) {
 213   const char* read_from = GetReadPointerAndAdvance(length);
 214   if (!read_from)
 215     return false;
 216   *data = read_from;
 217   return true;
 218 }
 219
 220 Pickle::Attachment::Attachment() = default;
 221
 222 Pickle::Attachment::~Attachment() = default;
 223
 224 // Payload is uint32_t aligned.
 225
 226 Pickle::Pickle()
 227     : header_(nullptr),
 228       header_size_(sizeof(Header)),
 229       capacity_after_header_(0),
 230       write_offset_(0) {
 231   static_assert(base::bits::IsPowerOfTwo(Pickle::kPayloadUnit),
 232                 "Pickle::kPayloadUnit must be a power of two");
 233   Resize(kPayloadUnit);
 234   header_->payload_size = 0;
 235 }
 236
 237 Pickle::Pickle(int header_size)
 238     : header_(nullptr),
 239       header_size_(bits::AlignUp(header_size, sizeof(uint32_t))),
 240       capacity_after_header_(0),
 241       write_offset_(0) {
 242   DCHECK_GE(static_cast<size_t>(header_size), sizeof(Header));
 243   DCHECK_LE(header_size, kPayloadUnit);
 244   Resize(kPayloadUnit);
 245   header_->payload_size = 0;
 246 }
 247
 248 Pickle::Pickle(const char* data, size_t data_len)
 249     : header_(reinterpret_cast<Header*>(const_cast<char*>(data))),
 250       header_size_(0),
 251       capacity_after_header_(kCapacityReadOnly),
 252       write_offset_(0) {
 253   if (data_len >= static_cast<int>(sizeof(Header)))
 254     header_size_ = data_len - header_->payload_size;
 255
 256   if (header_size_ > static_cast<unsigned int>(data_len))
 257     header_size_ = 0;
 258
 259   if (header_size_ != bits::AlignUp(header_size_, sizeof(uint32_t)))
 260     header_size_ = 0;
 261
 262   // If there is anything wrong with the data, we're not going to use it.
 263   if (!header_size_)
 264     header_ = nullptr;
 265 }
 266
 267 Pickle::Pickle(const Pickle& other)
 268     : header_(nullptr),
 269       header_size_(other.header_size_),
 270       capacity_after_header_(0),
 271       write_offset_(other.write_offset_) {
 272   Resize(other.header_->payload_size);
 273   memcpy(header_, other.header_, header_size_ + other.header_->payload_size);
 274 }
 275
 276 Pickle::~Pickle() {
 277   if (capacity_after_header_ != kCapacityReadOnly)
 278     free(header_);
 279 }
 280
 281 Pickle& Pickle::operator=(const Pickle& other) {
 282   if (this == &other) {
 283     return *this;
 284   }
 285   if (capacity_after_header_ == kCapacityReadOnly) {
 286     header_ = nullptr;
 287     capacity_after_header_ = 0;
 288   }
 289   if (header_size_ != other.header_size_) {
 290     free(header_);
 291     header_ = nullptr;
 292     header_size_ = other.header_size_;
 293   }
 294   Resize(other.header_->payload_size);
 295   memcpy(header_, other.header_,
 296          other.header_size_ + other.header_->payload_size);
 297   write_offset_ = other.write_offset_;
 298   return *this;
 299 }
 300
 301 void Pickle::WriteString(const StringPiece& value) {
 302   WriteInt(static_cast<int>(value.size()));
 303   WriteBytes(value.data(), static_cast<int>(value.size()));
 304 }
 305
 306 void Pickle::WriteString16(const StringPiece16& value) {
 307   WriteInt(static_cast<int>(value.size()));
 308   WriteBytes(value.data(), static_cast<int>(value.size()) * sizeof(char16_t));
 309 }
 310
 311 void Pickle::WriteData(const char* data, int length) {
 312   DCHECK_GE(length, 0);
 313   WriteInt(length);
 314   WriteBytes(data, length);
 315 }
 316
 317 void Pickle::WriteBytes(const void* data, int length) {
 318   WriteBytesCommon(data, length);
 319 }
 320
 321 void Pickle::Reserve(size_t length) {
 322   size_t data_len = bits::AlignUp(length, sizeof(uint32_t));
 323   DCHECK_GE(data_len, length);
 324 #ifdef ARCH_CPU_64_BITS
 325   DCHECK_LE(data_len, std::numeric_limits<uint32_t>::max());
 326 #endif
 327   DCHECK_LE(write_offset_, std::numeric_limits<uint32_t>::max() - data_len);
 328   size_t new_size = write_offset_ + data_len;
 329   if (new_size > capacity_after_header_)
 330     Resize(capacity_after_header_ * 2 + new_size);
 331 }
 332
 333 bool Pickle::WriteAttachment(scoped_refptr<Attachment> attachment) {
 334   return false;
 335 }
 336
 337 bool Pickle::ReadAttachment(base::PickleIterator* iter,
 338                             scoped_refptr<Attachment>* attachment) const {
 339   return false;
 340 }
 341
 342 bool Pickle::HasAttachments() const {
 343   return false;
 344 }
 345
 346 void Pickle::Resize(size_t new_capacity) {
 347   CHECK_NE(capacity_after_header_, kCapacityReadOnly);
 348   capacity_after_header_ = bits::AlignUp(new_capacity, kPayloadUnit);
 349   void* p = realloc(header_, GetTotalAllocatedSize());
 350   CHECK(p);
 351   header_ = reinterpret_cast<Header*>(p);
 352 }
 353
 354 void* Pickle::ClaimBytes(size_t num_bytes) {
 355   void* p = ClaimUninitializedBytesInternal(num_bytes);
 356   CHECK(p);
 357   memset(p, 0, num_bytes);
 358   return p;
 359 }
 360
 361 size_t Pickle::GetTotalAllocatedSize() const {
 362   if (capacity_after_header_ == kCapacityReadOnly)
 363     return 0;
 364   return header_size_ + capacity_after_header_;
 365 }
 366
 367 // static
 368 const char* Pickle::FindNext(size_t header_size,
 369                              const char* start,
 370                              const char* end) {
 371   size_t pickle_size = 0;
 372   if (!PeekNext(header_size, start, end, &pickle_size))
 373     return nullptr;
 374
 375   if (pickle_size > static_cast<size_t>(end - start))
 376     return nullptr;
 377
 378   return start + pickle_size;
 379 }
 380
 381 // static
 382 bool Pickle::PeekNext(size_t header_size,
 383                       const char* start,
 384                       const char* end,
 385                       size_t* pickle_size) {
 386   DCHECK_EQ(header_size, bits::AlignUp(header_size, sizeof(uint32_t)));
 387   DCHECK_GE(header_size, sizeof(Header));
 388   DCHECK_LE(header_size, static_cast<size_t>(kPayloadUnit));
 389
 390   size_t length = static_cast<size_t>(end - start);
 391   if (length < sizeof(Header))
 392     return false;
 393
 394   const Header* hdr = reinterpret_cast<const Header*>(start);
 395   if (length < header_size)
 396     return false;
 397
 398   // If payload_size causes an overflow, we return maximum possible
 399   // pickle size to indicate that.
 400   *pickle_size = ClampAdd(header_size, hdr->payload_size);
 401   return true;
 402 }
 403
 404 template <size_t length> void Pickle::WriteBytesStatic(const void* data) {
 405   WriteBytesCommon(data, length);
 406 }
 407
 408 template void Pickle::WriteBytesStatic<2>(const void* data);
 409 template void Pickle::WriteBytesStatic<4>(const void* data);
 410 template void Pickle::WriteBytesStatic<8>(const void* data);
 411
 412 inline void* Pickle::ClaimUninitializedBytesInternal(size_t length) {
 413   DCHECK_NE(kCapacityReadOnly, capacity_after_header_)
 414       << "oops: pickle is readonly";
 415   size_t data_len = bits::AlignUp(length, sizeof(uint32_t));
 416   DCHECK_GE(data_len, length);
 417 #ifdef ARCH_CPU_64_BITS
 418   DCHECK_LE(data_len, std::numeric_limits<uint32_t>::max());
 419 #endif
 420   DCHECK_LE(write_offset_, std::numeric_limits<uint32_t>::max() - data_len);
 421   size_t new_size = write_offset_ + data_len;
 422   if (new_size > capacity_after_header_) {
 423     size_t new_capacity = capacity_after_header_ * 2;
 424     const size_t kPickleHeapAlign = 4096;
 425     if (new_capacity > kPickleHeapAlign) {
 426       new_capacity =
 427           bits::AlignUp(new_capacity, kPickleHeapAlign) - kPayloadUnit;
 428     }
 429     Resize(std::max(new_capacity, new_size));
 430   }
 431
 432   char* write = mutable_payload() + write_offset_;
 433   memset(write + length, 0, data_len - length);  // Always initialize padding
 434   header_->payload_size = static_cast<uint32_t>(new_size);
 435   write_offset_ = new_size;
 436   return write;
 437 }
 438
 439 inline void Pickle::WriteBytesCommon(const void* data, size_t length) {
 440   DCHECK_NE(kCapacityReadOnly, capacity_after_header_)
 441       << "oops: pickle is readonly";
 442   MSAN_CHECK_MEM_IS_INITIALIZED(data, length);
 443   void* write = ClaimUninitializedBytesInternal(length);
 444   memcpy(write, data, length);
 445 }
 446
 447 }  // namespace base