168c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo// Copyright 2017 The Chromium OS Authors. All rights reserved. 268c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo// Use of this source code is governed by a BSD-style license that can be 368c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo// found in the LICENSE file. 468c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo 568c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo#include "bsdiff/diff_encoder.h" 668c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo 768c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo#include <vector> 868c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo 968c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo#include "bsdiff/logging.h" 1068c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo 1168c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymonamespace { 1268c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo 1368c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo// The maximum positive number that we should encode. A number larger than this 1468c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo// for unsigned fields will be interpreted as a negative value and thus a 1568c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo// corrupt patch. 1668c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymoconst uint64_t kMaxEncodedUint64Value = (1ULL << 63) - 1; 1768c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo 1868c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo} // namespace 1968c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo 2068c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymonamespace bsdiff { 2168c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo 224dadd8b4439358585be374226357b35aece52f17Alex Deymobool DiffEncoder::Init() { 234dadd8b4439358585be374226357b35aece52f17Alex Deymo return patch_->Init(new_size_); 244dadd8b4439358585be374226357b35aece52f17Alex Deymo} 254dadd8b4439358585be374226357b35aece52f17Alex Deymo 2668c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymobool DiffEncoder::AddControlEntry(const ControlEntry& entry) { 2768c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo if (entry.diff_size > kMaxEncodedUint64Value) { 2818480eb706be7479b899138410abc2c800337230Tianjie Xu LOG(ERROR) << "Encoding value out of range " << entry.diff_size; 2968c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo return false; 3068c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo } 3168c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo 3268c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo if (entry.extra_size > kMaxEncodedUint64Value) { 3318480eb706be7479b899138410abc2c800337230Tianjie Xu LOG(ERROR) << "Encoding value out of range " << entry.extra_size; 3468c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo return false; 3568c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo } 3668c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo 37aefc253cd9bbc2750748d37d3db1438332748d37Alex Deymo // entry.diff_size + entry.extra_size don't overflow in uint64_t since we 38aefc253cd9bbc2750748d37d3db1438332748d37Alex Deymo // checked the kMaxEncodedUint64Value limit before. 39aefc253cd9bbc2750748d37d3db1438332748d37Alex Deymo if (entry.diff_size + entry.extra_size > new_size_ - written_output_) { 4018480eb706be7479b899138410abc2c800337230Tianjie Xu LOG(ERROR) << "Wrote more output than the declared new_size"; 4168c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo return false; 4268c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo } 4368c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo 4468c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo if (entry.diff_size > 0 && 45aefc253cd9bbc2750748d37d3db1438332748d37Alex Deymo (old_pos_ < 0 || 46aefc253cd9bbc2750748d37d3db1438332748d37Alex Deymo static_cast<uint64_t>(old_pos_) + entry.diff_size > old_size_)) { 47aefc253cd9bbc2750748d37d3db1438332748d37Alex Deymo LOG(ERROR) << "The pointer in the old stream [" << old_pos_ << ", " 48aefc253cd9bbc2750748d37d3db1438332748d37Alex Deymo << (static_cast<uint64_t>(old_pos_) + entry.diff_size) 4918480eb706be7479b899138410abc2c800337230Tianjie Xu << ") is out of bounds [0, " << old_size_ << ")"; 5068c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo return false; 5168c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo } 5268c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo 5368c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo // Pass down the control entry. 5468c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo if (!patch_->AddControlEntry(entry)) 5568c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo return false; 5668c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo 5768c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo // Generate the diff stream. 5868c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo std::vector<uint8_t> diff(entry.diff_size); 5968c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo for (uint64_t i = 0; i < entry.diff_size; ++i) { 6068c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo diff[i] = new_buf_[written_output_ + i] - old_buf_[old_pos_ + i]; 6168c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo } 6268c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo if (!patch_->WriteDiffStream(diff.data(), diff.size())) { 6318480eb706be7479b899138410abc2c800337230Tianjie Xu LOG(ERROR) << "Writing " << diff.size() << " bytes to the diff stream"; 6468c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo return false; 6568c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo } 6668c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo 6768c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo if (!patch_->WriteExtraStream(new_buf_ + written_output_ + entry.diff_size, 6868c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo entry.extra_size)) { 6918480eb706be7479b899138410abc2c800337230Tianjie Xu LOG(ERROR) << "Writing " << entry.extra_size 7018480eb706be7479b899138410abc2c800337230Tianjie Xu << " bytes to the extra stream"; 7168c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo return false; 7268c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo } 7368c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo 7468c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo old_pos_ += entry.diff_size + entry.offset_increment; 7568c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo written_output_ += entry.diff_size + entry.extra_size; 7668c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo 7768c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo return true; 7868c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo} 7968c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo 8068c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymobool DiffEncoder::Close() { 8168c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo if (written_output_ != new_size_) { 8218480eb706be7479b899138410abc2c800337230Tianjie Xu LOG(ERROR) << "Close() called but not all the output was written"; 8368c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo return false; 8468c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo } 8568c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo return patch_->Close(); 8668c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo} 8768c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo 8868c0e7f20623158c007735100b95f2ccbc468ad7Alex Deymo} // namespace bsdiff 89