1 /* 2 * Copyright (C) 2015 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #include "unflatten/ResChunkPullParser.h" 18 19 #include <inttypes.h> 20 #include <cstddef> 21 22 #include "android-base/logging.h" 23 #include "android-base/stringprintf.h" 24 #include "androidfw/ResourceTypes.h" 25 26 #include "util/Util.h" 27 28 namespace aapt { 29 30 using android::ResChunk_header; 31 using android::base::StringPrintf; 32 ChunkHeaderDump(const ResChunk_header * header)33static std::string ChunkHeaderDump(const ResChunk_header* header) { 34 return StringPrintf("(type=%02" PRIx16 " header_size=%" PRIu16 " size=%" PRIu32 ")", 35 util::DeviceToHost16(header->type), util::DeviceToHost16(header->headerSize), 36 util::DeviceToHost32(header->size)); 37 } 38 Next()39ResChunkPullParser::Event ResChunkPullParser::Next() { 40 if (!IsGoodEvent(event_)) { 41 return event_; 42 } 43 44 if (event_ == Event::kStartDocument) { 45 current_chunk_ = data_; 46 } else { 47 current_chunk_ = 48 (const ResChunk_header*)(((const char*)current_chunk_) + 49 util::DeviceToHost32(current_chunk_->size)); 50 } 51 52 const std::ptrdiff_t diff = (const char*)current_chunk_ - (const char*)data_; 53 CHECK(diff >= 0) << "diff is negative"; 54 const size_t offset = static_cast<const size_t>(diff); 55 56 if (offset == len_) { 57 current_chunk_ = nullptr; 58 return (event_ = Event::kEndDocument); 59 } else if (offset + sizeof(ResChunk_header) > len_) { 60 error_ = "chunk is past the end of the document"; 61 current_chunk_ = nullptr; 62 return (event_ = Event::kBadDocument); 63 } 64 65 if (util::DeviceToHost16(current_chunk_->headerSize) < sizeof(ResChunk_header)) { 66 error_ = "chunk has too small header"; 67 current_chunk_ = nullptr; 68 return (event_ = Event::kBadDocument); 69 } else if (util::DeviceToHost32(current_chunk_->size) < 70 util::DeviceToHost16(current_chunk_->headerSize)) { 71 error_ = "chunk's total size is smaller than header " + ChunkHeaderDump(current_chunk_); 72 current_chunk_ = nullptr; 73 return (event_ = Event::kBadDocument); 74 } else if (offset + util::DeviceToHost32(current_chunk_->size) > len_) { 75 error_ = "chunk's data extends past the end of the document " + ChunkHeaderDump(current_chunk_); 76 current_chunk_ = nullptr; 77 return (event_ = Event::kBadDocument); 78 } 79 return (event_ = Event::kChunk); 80 } 81 82 } // namespace aapt 83