Mercurial > hg > CbC > CbC_llvm
comparison compiler-rt/test/fuzzer/SimpleHashTest.cpp @ 150:1d019706d866
LLVM10
author | anatofuz |
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date | Thu, 13 Feb 2020 15:10:13 +0900 |
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147:c2174574ed3a | 150:1d019706d866 |
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1 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. | |
2 // See https://llvm.org/LICENSE.txt for license information. | |
3 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception | |
4 | |
5 // This test computes a checksum of the data (all but the last 4 bytes), | |
6 // and then compares the last 4 bytes with the computed value. | |
7 // A fuzzer with cmp traces is expected to defeat this check. | |
8 #include <cstdint> | |
9 #include <cstdio> | |
10 #include <cstdlib> | |
11 #include <cstring> | |
12 | |
13 // A modified jenkins_one_at_a_time_hash initialized by non-zero, | |
14 // so that simple_hash(0) != 0. See also | |
15 // https://en.wikipedia.org/wiki/Jenkins_hash_function | |
16 static uint32_t simple_hash(const uint8_t *Data, size_t Size) { | |
17 uint32_t Hash = 0x12039854; | |
18 for (uint32_t i = 0; i < Size; i++) { | |
19 Hash += Data[i]; | |
20 Hash += (Hash << 10); | |
21 Hash ^= (Hash >> 6); | |
22 } | |
23 Hash += (Hash << 3); | |
24 Hash ^= (Hash >> 11); | |
25 Hash += (Hash << 15); | |
26 return Hash; | |
27 } | |
28 | |
29 extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) { | |
30 if (Size < 14) | |
31 return 0; | |
32 | |
33 uint32_t Hash = simple_hash(&Data[0], Size - 4); | |
34 uint32_t Want = reinterpret_cast<const uint32_t *>(&Data[Size - 4])[0]; | |
35 if (Hash != Want) | |
36 return 0; | |
37 fprintf(stderr, "BINGO; simple_hash defeated: %x == %x\n", (unsigned int)Hash, | |
38 (unsigned int)Want); | |
39 exit(1); | |
40 return 0; | |
41 } |