| 1 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
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| 2 | // See https://llvm.org/LICENSE.txt for license information. |
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| 3 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
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| 4 | |
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| 5 | // Make sure the fuzzer eventually finds all possible values of a variable |
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| 6 | // within a range. |
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| 7 | #include <cassert> |
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| 8 | #include <cstdint> |
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| 9 | #include <cstdio> |
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| 10 | #include <cstdlib> |
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| 11 | #include <cstring> |
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| 12 | #include <set> |
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| 13 | |
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| 14 | const size_t N = 1 << 12; |
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| 15 | |
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| 16 | // Define an array of counters that will be understood by libFuzzer |
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| 17 | // as extra coverage signal. The array must be: |
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| 18 | // * uint8_t |
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| 19 | // * in the section named __libfuzzer_extra_counters. |
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| 20 | // The target code may declare more than one such array. |
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| 21 | // |
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| 22 | // Use either `Counters[Idx] = 1` or `Counters[Idx]++;` |
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| 23 | // depending on whether multiple occurrences of the event 'Idx' |
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| 24 | // is important to distinguish from one occurrence. |
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| 25 | #if defined(__linux__) || defined(__FreeBSD__) |
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| 26 | __attribute__((section("__libfuzzer_extra_counters" ))) |
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| 27 | #endif |
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| 28 | #ifdef _WIN32 |
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| 29 | # pragma section(".data$__libfuzzer_extra_counters") |
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| 30 | __declspec(allocate(".data$__libfuzzer_extra_counters" )) |
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| 31 | #endif |
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| 32 | static uint8_t Counters[N]; |
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| 33 | |
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| 34 | extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) { |
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| 35 | static std::set<uint16_t> SeenIdx; |
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| 36 | if (Size != 4) return 0; |
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| 37 | uint32_t Idx; |
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| 38 | memcpy(dest: &Idx, src: Data, n: 4); |
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| 39 | Idx %= N; |
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| 40 | assert(Counters[Idx] == 0); // libFuzzer should reset these between the runs. |
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| 41 | // Or Counters[Idx]=1 if we don't care how many times this happened. |
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| 42 | Counters[Idx]++; |
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| 43 | SeenIdx.insert(x: Idx); |
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| 44 | if (SeenIdx.size() == N) { |
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| 45 | fprintf(stderr, format: "BINGO: found all values\n" ); |
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| 46 | abort(); |
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| 47 | } |
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| 48 | return 0; |
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| 49 | } |
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| 50 | |
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