From: Kees Cook <keescook@xxxxxxxxxxxx> Subject: ubsan: expand tests and reporting Expand the UBSAN tests to include some additional UB cases. Notably the out-of-bounds enum loading appears not to work. Also include per-test reporting, including the relevant CONFIG_UBSAN... Kconfigs. Link: https://lkml.kernel.org/r/20201203004437.389959-8-keescook@xxxxxxxxxxxx Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> Cc: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx> Cc: Ard Biesheuvel <ardb@xxxxxxxxxx> Cc: Arnd Bergmann <arnd@xxxxxxxx> Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx> Cc: George Popescu <georgepope@xxxxxxxxxxx> Cc: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Marco Elver <elver@xxxxxxxxxx> Cc: Masahiro Yamada <masahiroy@xxxxxxxxxx> Cc: Michal Marek <michal.lkml@xxxxxxxxxxx> Cc: Nathan Chancellor <natechancellor@xxxxxxxxx> Cc: Nick Desaulniers <ndesaulniers@xxxxxxxxxx> Cc: Peter Oberparleiter <oberpar@xxxxxxxxxxxxx> Cc: Randy Dunlap <rdunlap@xxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- lib/test_ubsan.c | 74 ++++++++++++++++++++++++++++++++++++++++----- 1 file changed, 66 insertions(+), 8 deletions(-) --- a/lib/test_ubsan.c~ubsan-expand-tests-and-reporting +++ a/lib/test_ubsan.c @@ -5,32 +5,54 @@ typedef void(*test_ubsan_fp)(void); +#define UBSAN_TEST(config, ...) do { \ + pr_info("%s " __VA_ARGS__ "%s(%s=%s)\n", __func__, \ + sizeof(" " __VA_ARGS__) > 2 ? " " : "", \ + #config, IS_ENABLED(config) ? "y" : "n"); \ + } while (0) + static void test_ubsan_add_overflow(void) { volatile int val = INT_MAX; + volatile unsigned int uval = UINT_MAX; + UBSAN_TEST(CONFIG_UBSAN_SIGNED_OVERFLOW); val += 2; + + UBSAN_TEST(CONFIG_UBSAN_UNSIGNED_OVERFLOW); + uval += 2; } static void test_ubsan_sub_overflow(void) { volatile int val = INT_MIN; + volatile unsigned int uval = 0; volatile int val2 = 2; + UBSAN_TEST(CONFIG_UBSAN_SIGNED_OVERFLOW); val -= val2; + + UBSAN_TEST(CONFIG_UBSAN_UNSIGNED_OVERFLOW); + uval -= val2; } static void test_ubsan_mul_overflow(void) { volatile int val = INT_MAX / 2; + volatile unsigned int uval = UINT_MAX / 2; + UBSAN_TEST(CONFIG_UBSAN_SIGNED_OVERFLOW); val *= 3; + + UBSAN_TEST(CONFIG_UBSAN_UNSIGNED_OVERFLOW); + uval *= 3; } static void test_ubsan_negate_overflow(void) { volatile int val = INT_MIN; + UBSAN_TEST(CONFIG_UBSAN_SIGNED_OVERFLOW); val = -val; } @@ -39,37 +61,67 @@ static void test_ubsan_divrem_overflow(v volatile int val = 16; volatile int val2 = 0; + UBSAN_TEST(CONFIG_UBSAN_DIV_ZERO); val /= val2; } static void test_ubsan_shift_out_of_bounds(void) { - volatile int val = -1; - int val2 = 10; + volatile int neg = -1, wrap = 4; + int val1 = 10; + int val2 = INT_MAX; + + UBSAN_TEST(CONFIG_UBSAN_SHIFT, "negative exponent"); + val1 <<= neg; - val2 <<= val; + UBSAN_TEST(CONFIG_UBSAN_SHIFT, "left overflow"); + val2 <<= wrap; } static void test_ubsan_out_of_bounds(void) { - volatile int i = 4, j = 5; + volatile int i = 4, j = 5, k = -1; + volatile char above[4] = { }; /* Protect surrounding memory. */ volatile int arr[4]; + volatile char below[4] = { }; /* Protect surrounding memory. */ + above[0] = below[0]; + + UBSAN_TEST(CONFIG_UBSAN_BOUNDS, "above"); arr[j] = i; + + UBSAN_TEST(CONFIG_UBSAN_BOUNDS, "below"); + arr[k] = i; } +enum ubsan_test_enum { + UBSAN_TEST_ZERO = 0, + UBSAN_TEST_ONE, + UBSAN_TEST_MAX, +}; + static void test_ubsan_load_invalid_value(void) { volatile char *dst, *src; bool val, val2, *ptr; - char c = 4; + enum ubsan_test_enum eval, eval2, *eptr; + unsigned char c = 0xff; + UBSAN_TEST(CONFIG_UBSAN_BOOL, "bool"); dst = (char *)&val; src = &c; *dst = *src; ptr = &val2; val2 = val; + + UBSAN_TEST(CONFIG_UBSAN_ENUM, "enum"); + dst = (char *)&eval; + src = &c; + *dst = *src; + + eptr = &eval2; + eval2 = eval; } static void test_ubsan_null_ptr_deref(void) @@ -77,6 +129,7 @@ static void test_ubsan_null_ptr_deref(vo volatile int *ptr = NULL; int val; + UBSAN_TEST(CONFIG_UBSAN_OBJECT_SIZE); val = *ptr; } @@ -85,6 +138,7 @@ static void test_ubsan_misaligned_access volatile char arr[5] __aligned(4) = {1, 2, 3, 4, 5}; volatile int *ptr, val = 6; + UBSAN_TEST(CONFIG_UBSAN_ALIGNMENT); ptr = (int *)(arr + 1); *ptr = val; } @@ -95,6 +149,7 @@ static void test_ubsan_object_size_misma volatile int val __aligned(8) = 4; volatile long long *ptr, val2; + UBSAN_TEST(CONFIG_UBSAN_OBJECT_SIZE); ptr = (long long *)&val; val2 = *ptr; } @@ -104,15 +159,19 @@ static const test_ubsan_fp test_ubsan_ar test_ubsan_sub_overflow, test_ubsan_mul_overflow, test_ubsan_negate_overflow, - test_ubsan_divrem_overflow, test_ubsan_shift_out_of_bounds, test_ubsan_out_of_bounds, test_ubsan_load_invalid_value, - //test_ubsan_null_ptr_deref, /* exclude it because there is a crash */ test_ubsan_misaligned_access, test_ubsan_object_size_mismatch, }; +/* Excluded because they Oops the module. */ +static const test_ubsan_fp skip_ubsan_array[] = { + test_ubsan_divrem_overflow, + test_ubsan_null_ptr_deref, +}; + static int __init test_ubsan_init(void) { unsigned int i; @@ -120,7 +179,6 @@ static int __init test_ubsan_init(void) for (i = 0; i < ARRAY_SIZE(test_ubsan_array); i++) test_ubsan_array[i](); - (void)test_ubsan_null_ptr_deref; /* to avoid unsed-function warning */ return 0; } module_init(test_ubsan_init); _
