blob: 8fc3219680559c5fe05598ef6ca4dfe72f839727 [file] [log] [blame]
Adam Lesinski7ad11102016-10-28 16:39:15 -07001/*
2 * Copyright (C) 2016 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
Adam Lesinskida431a22016-12-29 16:08:16 -050017#include "androidfw/Chunk.h"
Adam Lesinski7ad11102016-10-28 16:39:15 -070018
19#include "android-base/logging.h"
20
21namespace android {
22
23Chunk ChunkIterator::Next() {
24 CHECK(len_ != 0) << "called Next() after last chunk";
25
26 const ResChunk_header* this_chunk = next_chunk_;
27
28 // We've already checked the values of this_chunk, so safely increment.
29 next_chunk_ = reinterpret_cast<const ResChunk_header*>(
30 reinterpret_cast<const uint8_t*>(this_chunk) + dtohl(this_chunk->size));
31 len_ -= dtohl(this_chunk->size);
32
33 if (len_ != 0) {
34 // Prepare the next chunk.
Todd Kennedy28e663c2018-07-12 13:15:54 -070035 if (VerifyNextChunkNonFatal()) {
36 VerifyNextChunk();
37 }
Adam Lesinski7ad11102016-10-28 16:39:15 -070038 }
39 return Chunk(this_chunk);
40}
41
Todd Kennedy28e663c2018-07-12 13:15:54 -070042// TODO(b/111401637) remove this and have full resource file verification
43// Returns false if there was an error.
44bool ChunkIterator::VerifyNextChunkNonFatal() {
45 if (len_ < sizeof(ResChunk_header)) {
46 last_error_ = "not enough space for header";
47 last_error_was_fatal_ = false;
48 return false;
49 }
50 const size_t size = dtohl(next_chunk_->size);
51 if (size > len_) {
52 last_error_ = "chunk size is bigger than given data";
53 last_error_was_fatal_ = false;
54 return false;
55 }
56 return true;
57}
58
Adam Lesinski7ad11102016-10-28 16:39:15 -070059// Returns false if there was an error.
60bool ChunkIterator::VerifyNextChunk() {
61 const uintptr_t header_start = reinterpret_cast<uintptr_t>(next_chunk_);
62
63 // This data must be 4-byte aligned, since we directly
64 // access 32-bit words, which must be aligned on
65 // certain architectures.
66 if (header_start & 0x03) {
67 last_error_ = "header not aligned on 4-byte boundary";
68 return false;
69 }
70
71 if (len_ < sizeof(ResChunk_header)) {
72 last_error_ = "not enough space for header";
73 return false;
74 }
75
76 const size_t header_size = dtohs(next_chunk_->headerSize);
77 const size_t size = dtohl(next_chunk_->size);
78 if (header_size < sizeof(ResChunk_header)) {
79 last_error_ = "header size too small";
80 return false;
81 }
82
83 if (header_size > size) {
84 last_error_ = "header size is larger than entire chunk";
85 return false;
86 }
87
88 if (size > len_) {
89 last_error_ = "chunk size is bigger than given data";
90 return false;
91 }
92
93 if ((size | header_size) & 0x03) {
94 last_error_ = "header sizes are not aligned on 4-byte boundary";
95 return false;
96 }
97 return true;
98}
99
100} // namespace android