Re: [PATCH] selftests: do not macro-expand failed assertion expressions

[Kees Cook]

On Sun, Dec 9, 2018 at 3:00 PM Dmitry V. Levin <ldv@xxxxxxxxxxxx> wrote:
>
> I've stumbled over the current macro-expand behaviour of the test
> harness:
>
> $ gcc -Wall -xc - <<'__EOF__'
> TEST(macro) {
>         int status = 0;
>         ASSERT_TRUE(WIFSIGNALED(status));
> }
> TEST_HARNESS_MAIN
> __EOF__
> $ ./a.out
> [==========] Running 1 tests from 1 test cases.
> [ RUN      ] global.macro
> <stdin>:4:global.macro:Expected 0 (0) != (((signed char) (((status) & 0x7f) + 1) >> 1) > 0) (0)
> global.macro: Test terminated by assertion
> [     FAIL ] global.macro
> [==========] 0 / 1 tests passed.
> [  FAILED  ]
>
> With this change the output of the same test looks much more
> comprehensible:
>
> [==========] Running 1 tests from 1 test cases.
> [ RUN      ] global.macro
> <stdin>:4:global.macro:Expected 0 (0) != WIFSIGNALED(status) (0)
> global.macro: Test terminated by assertion
> [     FAIL ] global.macro
> [==========] 0 / 1 tests passed.
> [  FAILED  ]
>
> The issue is very similar to the bug fixed in glibc assert(3)
> three years ago:
> https://sourceware.org/bugzilla/show_bug.cgi?id=18604
>
> Cc: Shuah Khan <shuah@xxxxxxxxxx>
> Cc: Kees Cook <keescook@xxxxxxxxxxxx>
> Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
> Cc: Will Drewry <wad@xxxxxxxxxxxx>
> Cc: linux-kselftest@xxxxxxxxxxxxxxx
> Signed-off-by: Dmitry V. Levin <ldv@xxxxxxxxxxxx>

Yeah, good idea.

Acked-by: Kees Cook <keescook@xxxxxxxxxxxx>

-Kees


> ---
>  tools/testing/selftests/kselftest_harness.h | 42 ++++++++++-----------
>  1 file changed, 21 insertions(+), 21 deletions(-)
>
> diff --git a/tools/testing/selftests/kselftest_harness.h b/tools/testing/selftests/kselftest_harness.h
> index 6ae3730c4ee3..76d654ef3234 100644
> --- a/tools/testing/selftests/kselftest_harness.h
> +++ b/tools/testing/selftests/kselftest_harness.h
> @@ -354,7 +354,7 @@
>   * ASSERT_EQ(expected, measured): expected == measured
>   */
>  #define ASSERT_EQ(expected, seen) \
> -       __EXPECT(expected, seen, ==, 1)
> +       __EXPECT(expected, #expected, seen, #seen, ==, 1)
>
>  /**
>   * ASSERT_NE(expected, seen)
> @@ -365,7 +365,7 @@
>   * ASSERT_NE(expected, measured): expected != measured
>   */
>  #define ASSERT_NE(expected, seen) \
> -       __EXPECT(expected, seen, !=, 1)
> +       __EXPECT(expected, #expected, seen, #seen, !=, 1)
>
>  /**
>   * ASSERT_LT(expected, seen)
> @@ -376,7 +376,7 @@
>   * ASSERT_LT(expected, measured): expected < measured
>   */
>  #define ASSERT_LT(expected, seen) \
> -       __EXPECT(expected, seen, <, 1)
> +       __EXPECT(expected, #expected, seen, #seen, <, 1)
>
>  /**
>   * ASSERT_LE(expected, seen)
> @@ -387,7 +387,7 @@
>   * ASSERT_LE(expected, measured): expected <= measured
>   */
>  #define ASSERT_LE(expected, seen) \
> -       __EXPECT(expected, seen, <=, 1)
> +       __EXPECT(expected, #expected, seen, #seen, <=, 1)
>
>  /**
>   * ASSERT_GT(expected, seen)
> @@ -398,7 +398,7 @@
>   * ASSERT_GT(expected, measured): expected > measured
>   */
>  #define ASSERT_GT(expected, seen) \
> -       __EXPECT(expected, seen, >, 1)
> +       __EXPECT(expected, #expected, seen, #seen, >, 1)
>
>  /**
>   * ASSERT_GE(expected, seen)
> @@ -409,7 +409,7 @@
>   * ASSERT_GE(expected, measured): expected >= measured
>   */
>  #define ASSERT_GE(expected, seen) \
> -       __EXPECT(expected, seen, >=, 1)
> +       __EXPECT(expected, #expected, seen, #seen, >=, 1)
>
>  /**
>   * ASSERT_NULL(seen)
> @@ -419,7 +419,7 @@
>   * ASSERT_NULL(measured): NULL == measured
>   */
>  #define ASSERT_NULL(seen) \
> -       __EXPECT(NULL, seen, ==, 1)
> +       __EXPECT(NULL, "NULL", seen, #seen, ==, 1)
>
>  /**
>   * ASSERT_TRUE(seen)
> @@ -429,7 +429,7 @@
>   * ASSERT_TRUE(measured): measured != 0
>   */
>  #define ASSERT_TRUE(seen) \
> -       ASSERT_NE(0, seen)
> +       __EXPECT(0, "0", seen, #seen, !=, 1)
>
>  /**
>   * ASSERT_FALSE(seen)
> @@ -439,7 +439,7 @@
>   * ASSERT_FALSE(measured): measured == 0
>   */
>  #define ASSERT_FALSE(seen) \
> -       ASSERT_EQ(0, seen)
> +       __EXPECT(0, "0", seen, #seen, ==, 1)
>
>  /**
>   * ASSERT_STREQ(expected, seen)
> @@ -472,7 +472,7 @@
>   * EXPECT_EQ(expected, measured): expected == measured
>   */
>  #define EXPECT_EQ(expected, seen) \
> -       __EXPECT(expected, seen, ==, 0)
> +       __EXPECT(expected, #expected, seen, #seen, ==, 0)
>
>  /**
>   * EXPECT_NE(expected, seen)
> @@ -483,7 +483,7 @@
>   * EXPECT_NE(expected, measured): expected != measured
>   */
>  #define EXPECT_NE(expected, seen) \
> -       __EXPECT(expected, seen, !=, 0)
> +       __EXPECT(expected, #expected, seen, #seen, !=, 0)
>
>  /**
>   * EXPECT_LT(expected, seen)
> @@ -494,7 +494,7 @@
>   * EXPECT_LT(expected, measured): expected < measured
>   */
>  #define EXPECT_LT(expected, seen) \
> -       __EXPECT(expected, seen, <, 0)
> +       __EXPECT(expected, #expected, seen, #seen, <, 0)
>
>  /**
>   * EXPECT_LE(expected, seen)
> @@ -505,7 +505,7 @@
>   * EXPECT_LE(expected, measured): expected <= measured
>   */
>  #define EXPECT_LE(expected, seen) \
> -       __EXPECT(expected, seen, <=, 0)
> +       __EXPECT(expected, #expected, seen, #seen, <=, 0)
>
>  /**
>   * EXPECT_GT(expected, seen)
> @@ -516,7 +516,7 @@
>   * EXPECT_GT(expected, measured): expected > measured
>   */
>  #define EXPECT_GT(expected, seen) \
> -       __EXPECT(expected, seen, >, 0)
> +       __EXPECT(expected, #expected, seen, #seen, >, 0)
>
>  /**
>   * EXPECT_GE(expected, seen)
> @@ -527,7 +527,7 @@
>   * EXPECT_GE(expected, measured): expected >= measured
>   */
>  #define EXPECT_GE(expected, seen) \
> -       __EXPECT(expected, seen, >=, 0)
> +       __EXPECT(expected, #expected, seen, #seen, >=, 0)
>
>  /**
>   * EXPECT_NULL(seen)
> @@ -537,7 +537,7 @@
>   * EXPECT_NULL(measured): NULL == measured
>   */
>  #define EXPECT_NULL(seen) \
> -       __EXPECT(NULL, seen, ==, 0)
> +       __EXPECT(NULL, "NULL", seen, #seen, ==, 0)
>
>  /**
>   * EXPECT_TRUE(seen)
> @@ -547,7 +547,7 @@
>   * EXPECT_TRUE(measured): 0 != measured
>   */
>  #define EXPECT_TRUE(seen) \
> -       EXPECT_NE(0, seen)
> +       __EXPECT(0, "0", seen, #seen, !=, 0)
>
>  /**
>   * EXPECT_FALSE(seen)
> @@ -557,7 +557,7 @@
>   * EXPECT_FALSE(measured): 0 == measured
>   */
>  #define EXPECT_FALSE(seen) \
> -       EXPECT_EQ(0, seen)
> +       __EXPECT(0, "0", seen, #seen, ==, 0)
>
>  /**
>   * EXPECT_STREQ(expected, seen)
> @@ -597,7 +597,7 @@
>         if (_metadata->passed && _metadata->step < 255) \
>                 _metadata->step++;
>
> -#define __EXPECT(_expected, _seen, _t, _assert) do { \
> +#define __EXPECT(_expected, _expected_str, _seen, _seen_str, _t, _assert) do { \
>         /* Avoid multiple evaluation of the cases */ \
>         __typeof__(_expected) __exp = (_expected); \
>         __typeof__(_seen) __seen = (_seen); \
> @@ -606,8 +606,8 @@
>                 unsigned long long __exp_print = (uintptr_t)__exp; \
>                 unsigned long long __seen_print = (uintptr_t)__seen; \
>                 __TH_LOG("Expected %s (%llu) %s %s (%llu)", \
> -                        #_expected, __exp_print, #_t, \
> -                        #_seen, __seen_print); \
> +                        _expected_str, __exp_print, #_t, \
> +                        _seen_str, __seen_print); \
>                 _metadata->passed = 0; \
>                 /* Ensure the optional handler is triggered */ \
>                 _metadata->trigger = 1; \
> --
> ldv



--
Kees Cook