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1 /*
2     __ _____ _____ _____
3  __|  |   __|     |   | |  JSON for Modern C++ (fuzz test support)
4 |  |  |__   |  |  | | | |  version 3.10.0
5 |_____|_____|_____|_|___|  https://github.com/nlohmann/json
6 
7 This file implements a parser test suitable for fuzz testing. Given a byte
8 array data, it performs the following steps:
9 
10 - j1 = from_msgpack(data)
11 - vec = to_msgpack(j1)
12 - j2 = from_msgpack(vec)
13 - assert(j1 == j2)
14 
15 The provided function `LLVMFuzzerTestOneInput` can be used in different fuzzer
16 drivers.
17 
18 Licensed under the MIT License <http://opensource.org/licenses/MIT>.
19 */
20 
21 #include <iostream>
22 #include <sstream>
23 #include <nlohmann/json.hpp>
24 
25 using json = nlohmann::json;
26 
27 // see http://llvm.org/docs/LibFuzzer.html
LLVMFuzzerTestOneInput(const uint8_t * data,size_t size)28 extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size)
29 {
30     try
31     {
32         // step 1: parse input
33         std::vector<uint8_t> vec1(data, data + size);
34         json j1 = json::from_msgpack(vec1);
35 
36         try
37         {
38             // step 2: round trip
39             std::vector<uint8_t> vec2 = json::to_msgpack(j1);
40 
41             // parse serialization
42             json j2 = json::from_msgpack(vec2);
43 
44             // serializations must match
45             assert(json::to_msgpack(j2) == vec2);
46         }
47         catch (const json::parse_error&)
48         {
49             // parsing a MessagePack serialization must not fail
50             assert(false);
51         }
52     }
53     catch (const json::parse_error&)
54     {
55         // parse errors are ok, because input may be random bytes
56     }
57     catch (const json::type_error&)
58     {
59         // type errors can occur during parsing, too
60     }
61     catch (const json::out_of_range&)
62     {
63         // out of range errors may happen if provided sizes are excessive
64     }
65 
66     // return 0 - non-zero return values are reserved for future use
67     return 0;
68 }
69