1  // Copyright (c) 2019-present The Bitcoin Core developers
 2  // Distributed under the MIT software license, see the accompanying
 3  // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 4  
 5  #include <bech32.h>
 6  #include <test/fuzz/fuzz.h>
 7  #include <test/fuzz/FuzzedDataProvider.h>
 8  #include <test/util/str.h>
 9  #include <util/strencodings.h>
10  
11  #include <cassert>
12  #include <cstdint>
13  #include <string>
14  #include <vector>
15  
16  FUZZ_TARGET(bech32_random_decode)
17  {
18      auto limit = bech32::CharLimit::BECH32;
19      FuzzedDataProvider fdp(buffer.data(), buffer.size());
20      auto random_string = fdp.ConsumeRandomLengthString(limit + 1);
21      auto decoded = bech32::Decode(random_string, limit);
22  
23      if (decoded.hrp.empty()) {
24          assert(decoded.encoding == bech32::Encoding::INVALID);
25          assert(decoded.data.empty());
26      } else {
27          assert(decoded.encoding != bech32::Encoding::INVALID);
28          auto reencoded = bech32::Encode(decoded.encoding, decoded.hrp, decoded.data);
29          assert(CaseInsensitiveEqual(random_string, reencoded));
30      }
31  }
32  
33  // https://github.com/bitcoin/bips/blob/master/bip-0173.mediawiki and https://github.com/bitcoin/bips/blob/master/bip-0350.mediawiki
34  std::string GenerateRandomHRP(FuzzedDataProvider& fdp)
35  {
36      std::string hrp;
37      size_t length = fdp.ConsumeIntegralInRange<size_t>(1, 83);
38      for (size_t i = 0; i < length; ++i) {
39          // Generate lowercase ASCII characters in ([33-126] - ['A'-'Z']) range
40          char c = fdp.ConsumeBool()
41                   ? fdp.ConsumeIntegralInRange<char>(33, 'A' - 1)
42                   : fdp.ConsumeIntegralInRange<char>('Z' + 1, 126);
43          hrp += c;
44      }
45      return hrp;
46  }
47  
48  FUZZ_TARGET(bech32_roundtrip)
49  {
50      FuzzedDataProvider fdp(buffer.data(), buffer.size());
51      auto hrp = GenerateRandomHRP(fdp);
52  
53      auto input_chars = fdp.ConsumeBytes<unsigned char>(fdp.ConsumeIntegralInRange<size_t>(0, 82));
54      std::vector<uint8_t> converted_input;
55      ConvertBits<8, 5, true>([&](auto c) { converted_input.push_back(c); }, input_chars.begin(), input_chars.end());
56  
57      auto size = converted_input.size() + hrp.length() + std::string({bech32::SEPARATOR}).size() + bech32::CHECKSUM_SIZE;
58      if (size <= bech32::CharLimit::BECH32) {
59          for (auto encoding: {bech32::Encoding::BECH32, bech32::Encoding::BECH32M}) {
60              auto encoded = bech32::Encode(encoding, hrp, converted_input);
61              assert(!encoded.empty());
62  
63              const auto decoded = bech32::Decode(encoded);
64              assert(decoded.encoding == encoding);
65              assert(decoded.hrp == hrp);
66              assert(decoded.data == converted_input);
67          }
68      }
69  }