59 lines · cpp
1//===-- checksum_test.cpp ---------------------------------------*- C++ -*-===//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-exception6//7//===----------------------------------------------------------------------===//8 9#include "tests/scudo_unit_test.h"10 11#include "checksum.h"12 13#include <string.h>14 15static scudo::u16 computeSoftwareChecksum(scudo::u32 Seed, scudo::uptr *Array,16 scudo::uptr ArraySize) {17 scudo::u16 Checksum = static_cast<scudo::u16>(Seed & 0xffff);18 for (scudo::uptr I = 0; I < ArraySize; I++)19 Checksum = scudo::computeBSDChecksum(Checksum, Array[I]);20 return Checksum;21}22 23static scudo::u16 computeHardwareChecksum(scudo::u32 Seed, scudo::uptr *Array,24 scudo::uptr ArraySize) {25 scudo::u32 Crc = Seed;26 for (scudo::uptr I = 0; I < ArraySize; I++)27 Crc = scudo::computeHardwareCRC32(Crc, Array[I]);28 return static_cast<scudo::u16>((Crc & 0xffff) ^ (Crc >> 16));29}30 31typedef scudo::u16 (*ComputeChecksum)(scudo::u32, scudo::uptr *, scudo::uptr);32 33// This verifies that flipping bits in the data being checksummed produces a34// different checksum. We do not use random data to avoid flakyness.35template <ComputeChecksum F> static void verifyChecksumFunctionBitFlip() {36 scudo::uptr Array[sizeof(scudo::u64) / sizeof(scudo::uptr)];37 const scudo::uptr ArraySize = ARRAY_SIZE(Array);38 memset(Array, 0xaa, sizeof(Array));39 const scudo::u32 Seed = 0x41424343U;40 const scudo::u16 Reference = F(Seed, Array, ArraySize);41 scudo::u8 IdenticalChecksums = 0;42 for (scudo::uptr I = 0; I < ArraySize; I++) {43 for (scudo::uptr J = 0; J < SCUDO_WORDSIZE; J++) {44 Array[I] ^= scudo::uptr{1} << J;45 if (F(Seed, Array, ArraySize) == Reference)46 IdenticalChecksums++;47 Array[I] ^= scudo::uptr{1} << J;48 }49 }50 // Allow for a couple of identical checksums over the whole set of flips.51 EXPECT_LE(IdenticalChecksums, 2);52}53 54TEST(ScudoChecksumTest, ChecksumFunctions) {55 verifyChecksumFunctionBitFlip<computeSoftwareChecksum>();56 if (&scudo::computeHardwareCRC32 && scudo::hasHardwareCRC32())57 verifyChecksumFunctionBitFlip<computeHardwareChecksum>();58}59