1 //===-- yaml-parser-fuzzer.cpp - Fuzzer for YAML parser -------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8
9 #include "llvm/ADT/StringRef.h"
10 #include "llvm/Support/YAMLParser.h"
11
12 using namespace llvm;
13
isValidYaml(const uint8_t * Data,size_t Size)14 static bool isValidYaml(const uint8_t *Data, size_t Size) {
15 SourceMgr SM;
16 yaml::Stream Stream(StringRef(reinterpret_cast<const char *>(Data), Size),
17 SM);
18 return Stream.validate();
19 }
20
LLVMFuzzerTestOneInput(const uint8_t * Data,size_t Size)21 extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
22 std::vector<uint8_t> Input(Data, Data + Size);
23
24 // Ensure we don't crash on any arbitrary byte string.
25 isValidYaml(Input.data(), Input.size());
26
27 // Ensure we don't crash on byte strings with no null characters.
28 llvm::erase_value(Input, 0);
29 Input.shrink_to_fit();
30 bool IsValidWithout0s = isValidYaml(Input.data(), Input.size());
31
32 // Ensure we don't crash on byte strings where the only null character is
33 // one-past-the-end of the actual input to the parser.
34 Input.push_back(0);
35 Input.shrink_to_fit();
36 bool IsValidWhen0Terminated = isValidYaml(Input.data(), Input.size() - 1);
37
38 // Ensure we don't crash on byte strings with no null characters, but with
39 // an invalid character one-past-the-end of the actual input to the parser.
40 Input.back() = 1;
41 bool IsValidWhen1Terminated = isValidYaml(Input.data(), Input.size() - 1);
42
43 // The parser should either accept all of these inputs, or reject all of
44 // them, because the parser sees an identical byte string in each case. This
45 // should hopefully catch some cases where the parser is sensitive to what is
46 // present one-past-the-end of the actual input.
47 if (IsValidWithout0s != IsValidWhen0Terminated ||
48 IsValidWhen0Terminated != IsValidWhen1Terminated)
49 LLVM_BUILTIN_TRAP;
50
51 return 0;
52 }
53