onionHEN/source/util/tests/test_hotpatch.cpp

/* Host regression tests for atomic x86-64 entry-patch construction. */
#include "test_harness.h"

#include <onion/hotpatch.h>

#include <cstdint>
#include <cstring>

namespace {

uint64_t read_u64(const uint8_t *p) {
  uint64_t value = 0;
  std::memcpy(&value, p, sizeof(value));
  return value;
}

int test_builds_absolute_jump_and_preserves_tail() {
  uint8_t current[ONION_X64_ATOMIC_PATCH_SIZE];
  for (size_t i = 0; i < sizeof(current); ++i)
    current[i] = static_cast<uint8_t>(0xa0 + i);

  onion_x64_atomic_patch patch{};
  constexpr uintptr_t target = 0x1000;
  constexpr uintptr_t hook = 0x123456789abcdef0ULL;
  TEST_ASSERT_TRUE(
      onion_x64_build_atomic_patch(target, current, hook, &patch));

  TEST_ASSERT_MEMEQ(current, patch.expected, sizeof(current));
  const uint8_t prefix[] = {0xff, 0x25, 0, 0, 0, 0};
  TEST_ASSERT_MEMEQ(prefix, patch.desired, sizeof(prefix));
  TEST_ASSERT_EQ_U64(hook, read_u64(patch.desired + sizeof(prefix)));
  TEST_ASSERT_EQ_INT(current[14], patch.desired[14]);
  TEST_ASSERT_EQ_INT(current[15], patch.desired[15]);
  return 0;
}

int test_rejects_unaligned_target() {
  uint8_t current[ONION_X64_ATOMIC_PATCH_SIZE] = {};
  onion_x64_atomic_patch patch{};
  TEST_ASSERT_TRUE(
      !onion_x64_build_atomic_patch(0x1008, current, 0x2000, &patch));
  return 0;
}

int test_rejects_invalid_arguments() {
  uint8_t current[ONION_X64_ATOMIC_PATCH_SIZE] = {};
  onion_x64_atomic_patch patch{};
  TEST_ASSERT_TRUE(!onion_x64_build_atomic_patch(0x1000, nullptr, 0x2000,
                                                  &patch));
  TEST_ASSERT_TRUE(!onion_x64_build_atomic_patch(0x1000, current, 0, &patch));
  TEST_ASSERT_TRUE(
      !onion_x64_build_atomic_patch(0x1000, current, 0x2000, nullptr));
  return 0;
}

} // namespace

extern "C" int test_hotpatch_suite(void) {
  int failures = 0;
  failures += onion_test_run("hotpatch.build",
                             test_builds_absolute_jump_and_preserves_tail);
  failures +=
      onion_test_run("hotpatch.alignment", test_rejects_unaligned_target);
  failures +=
      onion_test_run("hotpatch.arguments", test_rejects_invalid_arguments);
  return failures;
}