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/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