Adam Lesinski | 970bd8d | 2017-09-25 13:21:55 -0700 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright (C) 2017 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 | #define ATRACE_TAG ATRACE_TAG_RESOURCES |
| 18 | |
| 19 | #include "androidfw/Idmap.h" |
| 20 | |
| 21 | #include "android-base/logging.h" |
| 22 | #include "android-base/stringprintf.h" |
| 23 | #include "utils/ByteOrder.h" |
| 24 | #include "utils/Trace.h" |
| 25 | |
| 26 | #ifdef _WIN32 |
| 27 | #ifdef ERROR |
| 28 | #undef ERROR |
| 29 | #endif |
| 30 | #endif |
| 31 | |
| 32 | #include "androidfw/ResourceTypes.h" |
| 33 | |
| 34 | using ::android::base::StringPrintf; |
| 35 | |
| 36 | namespace android { |
| 37 | |
| 38 | constexpr static inline bool is_valid_package_id(uint16_t id) { |
| 39 | return id != 0 && id <= 255; |
| 40 | } |
| 41 | |
| 42 | constexpr static inline bool is_valid_type_id(uint16_t id) { |
| 43 | // Type IDs and package IDs have the same constraints in the IDMAP. |
| 44 | return is_valid_package_id(id); |
| 45 | } |
| 46 | |
| 47 | bool LoadedIdmap::Lookup(const IdmapEntry_header* header, uint16_t input_entry_id, |
| 48 | uint16_t* output_entry_id) { |
| 49 | if (input_entry_id < dtohs(header->entry_id_offset)) { |
| 50 | // After applying the offset, the entry is not present. |
| 51 | return false; |
| 52 | } |
| 53 | |
| 54 | input_entry_id -= dtohs(header->entry_id_offset); |
| 55 | if (input_entry_id >= dtohs(header->entry_count)) { |
| 56 | // The entry is not present. |
| 57 | return false; |
| 58 | } |
| 59 | |
| 60 | uint32_t result = dtohl(header->entries[input_entry_id]); |
| 61 | if (result == 0xffffffffu) { |
| 62 | return false; |
| 63 | } |
| 64 | *output_entry_id = static_cast<uint16_t>(result); |
| 65 | return true; |
| 66 | } |
| 67 | |
| 68 | static bool is_word_aligned(const void* data) { |
| 69 | return (reinterpret_cast<uintptr_t>(data) & 0x03) == 0; |
| 70 | } |
| 71 | |
| 72 | static bool IsValidIdmapHeader(const StringPiece& data) { |
| 73 | if (!is_word_aligned(data.data())) { |
| 74 | LOG(ERROR) << "Idmap header is not word aligned."; |
| 75 | return false; |
| 76 | } |
| 77 | |
| 78 | if (data.size() < sizeof(Idmap_header)) { |
| 79 | LOG(ERROR) << "Idmap header is too small."; |
| 80 | return false; |
| 81 | } |
| 82 | |
| 83 | const Idmap_header* header = reinterpret_cast<const Idmap_header*>(data.data()); |
| 84 | if (dtohl(header->magic) != kIdmapMagic) { |
| 85 | LOG(ERROR) << StringPrintf("Invalid Idmap file: bad magic value (was 0x%08x, expected 0x%08x)", |
| 86 | dtohl(header->magic), kIdmapMagic); |
| 87 | return false; |
| 88 | } |
| 89 | |
| 90 | if (dtohl(header->version) != kIdmapCurrentVersion) { |
| 91 | // We are strict about versions because files with this format are auto-generated and don't need |
| 92 | // backwards compatibility. |
| 93 | LOG(ERROR) << StringPrintf("Version mismatch in Idmap (was 0x%08x, expected 0x%08x)", |
| 94 | dtohl(header->version), kIdmapCurrentVersion); |
| 95 | return false; |
| 96 | } |
| 97 | |
| 98 | if (!is_valid_package_id(dtohs(header->target_package_id))) { |
| 99 | LOG(ERROR) << StringPrintf("Target package ID in Idmap is invalid: 0x%02x", |
| 100 | dtohs(header->target_package_id)); |
| 101 | return false; |
| 102 | } |
| 103 | |
| 104 | if (dtohs(header->type_count) > 255) { |
| 105 | LOG(ERROR) << StringPrintf("Idmap has too many type mappings (was %d, max 255)", |
| 106 | (int)dtohs(header->type_count)); |
| 107 | return false; |
| 108 | } |
| 109 | return true; |
| 110 | } |
| 111 | |
| 112 | LoadedIdmap::LoadedIdmap(const Idmap_header* header) : header_(header) { |
| 113 | size_t length = strnlen(reinterpret_cast<const char*>(header_->overlay_path), |
| 114 | arraysize(header_->overlay_path)); |
| 115 | overlay_apk_path_.assign(reinterpret_cast<const char*>(header_->overlay_path), length); |
| 116 | } |
| 117 | |
| 118 | std::unique_ptr<const LoadedIdmap> LoadedIdmap::Load(const StringPiece& idmap_data) { |
| 119 | ATRACE_CALL(); |
| 120 | if (!IsValidIdmapHeader(idmap_data)) { |
| 121 | return {}; |
| 122 | } |
| 123 | |
| 124 | const Idmap_header* header = reinterpret_cast<const Idmap_header*>(idmap_data.data()); |
| 125 | |
| 126 | // Can't use make_unique because LoadedImpl constructor is private. |
| 127 | std::unique_ptr<LoadedIdmap> loaded_idmap = std::unique_ptr<LoadedIdmap>(new LoadedIdmap(header)); |
| 128 | |
| 129 | const uint8_t* data_ptr = reinterpret_cast<const uint8_t*>(idmap_data.data()) + sizeof(*header); |
| 130 | size_t data_size = idmap_data.size() - sizeof(*header); |
| 131 | |
| 132 | size_t type_maps_encountered = 0u; |
| 133 | while (data_size >= sizeof(IdmapEntry_header)) { |
| 134 | if (!is_word_aligned(data_ptr)) { |
| 135 | LOG(ERROR) << "Type mapping in Idmap is not word aligned"; |
| 136 | return {}; |
| 137 | } |
| 138 | |
| 139 | // Validate the type IDs. |
| 140 | const IdmapEntry_header* entry_header = reinterpret_cast<const IdmapEntry_header*>(data_ptr); |
| 141 | if (!is_valid_type_id(dtohs(entry_header->target_type_id)) || !is_valid_type_id(dtohs(entry_header->overlay_type_id))) { |
| 142 | LOG(ERROR) << StringPrintf("Invalid type map (0x%02x -> 0x%02x)", |
| 143 | dtohs(entry_header->target_type_id), |
| 144 | dtohs(entry_header->overlay_type_id)); |
| 145 | return {}; |
| 146 | } |
| 147 | |
| 148 | // Make sure there is enough space for the entries declared in the header. |
| 149 | if ((data_size - sizeof(*entry_header)) / sizeof(uint32_t) < |
| 150 | static_cast<size_t>(dtohs(entry_header->entry_count))) { |
| 151 | LOG(ERROR) << StringPrintf("Idmap too small for the number of entries (%d)", |
| 152 | (int)dtohs(entry_header->entry_count)); |
| 153 | return {}; |
| 154 | } |
| 155 | |
| 156 | // Only add a non-empty overlay. |
| 157 | if (dtohs(entry_header->entry_count != 0)) { |
| 158 | loaded_idmap->type_map_[static_cast<uint8_t>(dtohs(entry_header->overlay_type_id))] = |
| 159 | entry_header; |
| 160 | } |
| 161 | |
| 162 | const size_t entry_size_bytes = |
| 163 | sizeof(*entry_header) + (dtohs(entry_header->entry_count) * sizeof(uint32_t)); |
| 164 | data_ptr += entry_size_bytes; |
| 165 | data_size -= entry_size_bytes; |
| 166 | type_maps_encountered++; |
| 167 | } |
| 168 | |
| 169 | // Verify that we parsed all the type maps. |
| 170 | if (type_maps_encountered != static_cast<size_t>(dtohs(header->type_count))) { |
| 171 | LOG(ERROR) << "Parsed " << type_maps_encountered << " type maps but expected " |
| 172 | << (int)dtohs(header->type_count); |
| 173 | return {}; |
| 174 | } |
| 175 | return std::move(loaded_idmap); |
| 176 | } |
| 177 | |
| 178 | uint8_t LoadedIdmap::TargetPackageId() const { |
| 179 | return static_cast<uint8_t>(dtohs(header_->target_package_id)); |
| 180 | } |
| 181 | |
| 182 | const IdmapEntry_header* LoadedIdmap::GetEntryMapForType(uint8_t type_id) const { |
| 183 | auto iter = type_map_.find(type_id); |
| 184 | if (iter != type_map_.end()) { |
| 185 | return iter->second; |
| 186 | } |
| 187 | return nullptr; |
| 188 | } |
| 189 | |
| 190 | } // namespace android |