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author | George Karpenkov <ekarpenkov@apple.com> | 2017-08-21 23:25:50 +0000 |
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committer | George Karpenkov <ekarpenkov@apple.com> | 2017-08-21 23:25:50 +0000 |
commit | 0c8339c8aab25f1156558e9e2082b4b124dc2327 (patch) | |
tree | 4f04d28abce4cbaa73fbba2b64f56af353e0f08b /test/fuzzer/SimpleHashTest.cpp | |
parent | 1a32c939c5eece22f3ca6cf70bd05a1527bc0970 (diff) |
Move libFuzzer to compiler_rt.
Resulting library binaries will be named libclang_rt.fuzzer*, and will
be placed in Clang toolchain, allowing redistribution.
Differential Revision: https://reviews.llvm.org/D36908
git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@311407 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'test/fuzzer/SimpleHashTest.cpp')
-rw-r--r-- | test/fuzzer/SimpleHashTest.cpp | 40 |
1 files changed, 40 insertions, 0 deletions
diff --git a/test/fuzzer/SimpleHashTest.cpp b/test/fuzzer/SimpleHashTest.cpp new file mode 100644 index 000000000..99e96cb25 --- /dev/null +++ b/test/fuzzer/SimpleHashTest.cpp @@ -0,0 +1,40 @@ +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. + +// This test computes a checksum of the data (all but the last 4 bytes), +// and then compares the last 4 bytes with the computed value. +// A fuzzer with cmp traces is expected to defeat this check. +#include <cstdint> +#include <cstdio> +#include <cstdlib> +#include <cstring> + +// A modified jenkins_one_at_a_time_hash initialized by non-zero, +// so that simple_hash(0) != 0. See also +// https://en.wikipedia.org/wiki/Jenkins_hash_function +static uint32_t simple_hash(const uint8_t *Data, size_t Size) { + uint32_t Hash = 0x12039854; + for (uint32_t i = 0; i < Size; i++) { + Hash += Data[i]; + Hash += (Hash << 10); + Hash ^= (Hash >> 6); + } + Hash += (Hash << 3); + Hash ^= (Hash >> 11); + Hash += (Hash << 15); + return Hash; +} + +extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) { + if (Size < 14) + return 0; + + uint32_t Hash = simple_hash(&Data[0], Size - 4); + uint32_t Want = reinterpret_cast<const uint32_t *>(&Data[Size - 4])[0]; + if (Hash != Want) + return 0; + fprintf(stderr, "BINGO; simple_hash defeated: %x == %x\n", (unsigned int)Hash, + (unsigned int)Want); + exit(1); + return 0; +} |