From b5500b9ca0102f1ccaf32f0e77e96d0739aded9b Mon Sep 17 00:00:00 2001 From: pascal Date: Sat, 3 Sep 2016 22:46:54 +0000 Subject: Use the space freed up by sparc and zaurus to import LLVM. ok hackroom@ --- gnu/llvm/lib/Fuzzer/test/SimpleHashTest.cpp | 37 +++++++++++++++++++++++++++++ 1 file changed, 37 insertions(+) create mode 100644 gnu/llvm/lib/Fuzzer/test/SimpleHashTest.cpp (limited to 'gnu/llvm/lib/Fuzzer/test/SimpleHashTest.cpp') diff --git a/gnu/llvm/lib/Fuzzer/test/SimpleHashTest.cpp b/gnu/llvm/lib/Fuzzer/test/SimpleHashTest.cpp new file mode 100644 index 00000000000..5bab3fa7f64 --- /dev/null +++ b/gnu/llvm/lib/Fuzzer/test/SimpleHashTest.cpp @@ -0,0 +1,37 @@ +// 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 +#include +#include +#include + +// 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(&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; +} -- cgit v1.2.3-59-g8ed1b