1 /*
2 __ _____ _____ _____
3 __| | __| | | | JSON for Modern C++ (fuzz test support)
4 | | |__ | | | | | | version 3.9.1
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_ubjson(data)
11 - vec = to_ubjson(j1)
12 - j2 = from_ubjson(vec)
13 - assert(j1 == j2)
14 - vec2 = to_ubjson(j1, use_size = true, use_type = false)
15 - j3 = from_ubjson(vec2)
16 - assert(j1 == j3)
17 - vec3 = to_ubjson(j1, use_size = true, use_type = true)
18 - j4 = from_ubjson(vec3)
19 - assert(j1 == j4)
20
21 The provided function `LLVMFuzzerTestOneInput` can be used in different fuzzer
22 drivers.
23
24 Licensed under the MIT License <http://opensource.org/licenses/MIT>.
25 */
26
27 #include <iostream>
28 #include <sstream>
29 #include <nlohmann/json.hpp>
30
31 using json = nlohmann::json;
32
33 // see http://llvm.org/docs/LibFuzzer.html
LLVMFuzzerTestOneInput(const uint8_t * data,size_t size)34 extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size)
35 {
36 try
37 {
38 // step 1: parse input
39 std::vector<uint8_t> vec1(data, data + size);
40 json j1 = json::from_ubjson(vec1);
41
42 try
43 {
44 // step 2.1: round trip without adding size annotations to container types
45 std::vector<uint8_t> vec2 = json::to_ubjson(j1, false, false);
46
47 // step 2.2: round trip with adding size annotations but without adding type annonations to container types
48 std::vector<uint8_t> vec3 = json::to_ubjson(j1, true, false);
49
50 // step 2.3: round trip with adding size as well as type annotations to container types
51 std::vector<uint8_t> vec4 = json::to_ubjson(j1, true, true);
52
53 // parse serialization
54 json j2 = json::from_ubjson(vec2);
55 json j3 = json::from_ubjson(vec3);
56 json j4 = json::from_ubjson(vec4);
57
58 // serializations must match
59 assert(json::to_ubjson(j2, false, false) == vec2);
60 assert(json::to_ubjson(j3, true, false) == vec3);
61 assert(json::to_ubjson(j4, true, true) == vec4);
62 }
63 catch (const json::parse_error&)
64 {
65 // parsing a UBJSON serialization must not fail
66 assert(false);
67 }
68 }
69 catch (const json::parse_error&)
70 {
71 // parse errors are ok, because input may be random bytes
72 }
73 catch (const json::type_error&)
74 {
75 // type errors can occur during parsing, too
76 }
77 catch (const json::out_of_range&)
78 {
79 // out of range errors may happen if provided sizes are excessive
80 }
81
82 // return 0 - non-zero return values are reserved for future use
83 return 0;
84 }
85