hardened_memory_unittest.cc

// Copyright lowRISC contributors (OpenTitan project).
// Licensed under the Apache License, Version 2.0, see LICENSE for details.
// SPDX-License-Identifier: Apache-2.0
 
#include "sw/device/lib/base/hardened_memory.h"
 
#include <vector>
 
#include "gmock/gmock.h"
#include "gtest/gtest.h"
 
// NOTE: This test does not verify hardening measures; it only checks that the
// "normal" contract of the functions is upheld.
 
namespace hardened_memory_unittest {
namespace {
 
using ::testing::Each;
using ::testing::ElementsAre;
 
TEST(HardenedMemory, Memcpy) {
  std::vector<uint32_t> xs = {1, 2, 3, 4, 5, 6, 7, 8};
  std::vector<uint32_t> ys(8);
 
  hardened_memcpy(ys.data(), xs.data(), 0);
  EXPECT_THAT(ys, Each(0));
 
  hardened_memcpy(ys.data() + 1, xs.data(), 7);
  EXPECT_THAT(ys, ElementsAre(0, 1, 2, 3, 4, 5, 6, 7));
}
 
constexpr uint32_t kRandomWord = 0xdeadbeef;
 
// Override whatever the default randomness source is so we can verify it
// actually gets used.
extern "C" size_t hardened_memshred_random_word() { return kRandomWord; }
 
TEST(HardenedMemory, MemShred) {
  std::vector<uint32_t> xs = {1, 2, 3, 4, 5, 6, 7, 8};
  hardened_memshred(xs.data(), xs.size());
 
  EXPECT_THAT(xs, Each(kRandomWord));
}
 
TEST(HardenedMemory, MemEq) {
  std::vector<uint32_t> xs = {1, 2, 3, 4, 5, 6, 7, 8};
  std::vector<uint32_t> ys = xs;
 
  EXPECT_EQ(hardened_memeq(ys.data(), xs.data(), xs.size()), kHardenedBoolTrue);
 
  ++ys[5];
  EXPECT_EQ(hardened_memeq(ys.data(), xs.data(), xs.size()),
            kHardenedBoolFalse);
}
 
}  // namespace
}  // namespace hardened_memory_unittest