1 /*
2 * Copyright (c) 2023 Huawei Device Co., Ltd.
3 * Licensed under the Apache License, Version 2.0 (the "License");
4 * you may not use this file except in compliance with the License.
5 * You may obtain a copy of the License at
6 *
7 * http://www.apache.org/licenses/LICENSE-2.0
8 *
9 * Unless required by applicable law or agreed to in writing, software
10 * distributed under the License is distributed on an "AS IS" BASIS,
11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 * See the License for the specific language governing permissions and
13 * limitations under the License.
14 */
15
16 #include "utils.h"
17 #include <fstream>
18 #include <iomanip>
19 #include "utils/logger.h"
20
21 namespace panda::verifier {
22
GenerateModifiedAbc(const std::vector<unsigned char> & buffer,const std::string & filename)23 void GenerateModifiedAbc(const std::vector<unsigned char> &buffer, const std::string &filename)
24 {
25 std::ofstream abc_file(filename, std::ios::out | std::ios::binary);
26 if (abc_file.fail()) {
27 LOG(ERROR, VERIFIER) << "Failed to open file " << filename;
28 return;
29 }
30
31 abc_file.write(reinterpret_cast<const char *>(buffer.data()), buffer.size());
32 abc_file.close();
33 }
34
ConvertToLittleEndian(std::vector<unsigned char> & inner_id,const uint32_t & id)35 void ConvertToLittleEndian(std::vector<unsigned char> &inner_id, const uint32_t &id)
36 {
37 std::vector<unsigned char> bytes;
38 for (int i = 0; i < sizeof(uint32_t); ++i) {
39 unsigned char byte = static_cast<unsigned char>((id >> (i * 8)) & 0xff);
40 inner_id.push_back(byte);
41 }
42 }
43
ModifyBuffer(std::unordered_map<uint32_t,uint32_t> & literal_map,std::vector<unsigned char> & buffer)44 void ModifyBuffer(std::unordered_map<uint32_t, uint32_t> &literal_map, std::vector<unsigned char> &buffer)
45 {
46 for (const auto &literal : literal_map) {
47 size_t literal_id = literal.first;
48 std::vector<unsigned char> inner_id;
49 ConvertToLittleEndian(inner_id, literal.second);
50 for (size_t i = literal_id; i < buffer.size(); ++i) {
51 if (buffer[i] == inner_id[0] && buffer[i+1] == inner_id[1]) {
52 // The purpose of this modification is to break abc
53 // The abc is tampered with by setting buffer[i + 1] to buffer[i] and buffer[i + 2] to buffer[i + 1]
54 buffer[i] = buffer[i + 1];
55 buffer[i + 1] = buffer[i + 2];
56 break;
57 }
58 }
59 }
60 }
61
62 } // namespace panda::verifier