Commit 4a26f49b authored by Kees Cook's avatar Kees Cook Committed by Linus Torvalds
Browse files

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@chromium.org


Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: George Popescu <georgepope@android.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Marco Elver <elver@google.com>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Michal Marek <michal.lkml@markovi.net>
Cc: Nathan Chancellor <natechancellor@gmail.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Peter Oberparleiter <oberpar@linux.ibm.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent c637693b

lib/test_ubsan.c

+66 −8
Original line number Diff line number Diff line
@@ -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(void) 
	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(void) 
	volatile int *ptr = NULL;

	int val;



	UBSAN_TEST(CONFIG_UBSAN_OBJECT_SIZE);

	val = *ptr;

}
@@ -85,6 +138,7 @@ static void test_ubsan_misaligned_access(void) 
	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_mismatch(void) 
	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_array[] = { 
	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);

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