Commit 58b999d7 authored by Andrey Konovalov's avatar Andrey Konovalov Committed by Linus Torvalds
Browse files

kasan: adopt KUNIT tests to SW_TAGS mode 



Now that we have KASAN-KUNIT tests integration, it's easy to see that
some KASAN tests are not adopted to the SW_TAGS mode and are failing.

Adjust the allocation size for kasan_memchr() and kasan_memcmp() by
roung it up to OOB_TAG_OFF so the bad access ends up in a separate
memory granule.

Add a new kmalloc_uaf_16() tests that relies on UAF, and a new
kasan_bitops_tags() test that is tailored to tag-based mode, as it's
hard to adopt the existing kmalloc_oob_16() and kasan_bitops_generic()
(renamed from kasan_bitops()) without losing the precision.

Add new kmalloc_uaf_16() and kasan_bitops_uaf() tests that rely on UAFs,
as it's hard to adopt the existing kmalloc_oob_16() and
kasan_bitops_oob() (rename from kasan_bitops()) without losing the
precision.

Disable kasan_global_oob() and kasan_alloca_oob_left/right() as SW_TAGS
mode doesn't instrument globals nor dynamic allocas.

Signed-off-by: default avatarAndrey Konovalov <andreyknvl@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Tested-by: default avatarDavid Gow <davidgow@google.com>
Link: https://lkml.kernel.org/r/76eee17b6531ca8b3ca92b240cb2fd23204aaff7.1603129942.git.andreyknvl@google.com


Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 8de15e92

lib/test_kasan.c

+107 −42
Original line number Diff line number Diff line
@@ -216,6 +216,12 @@ static void kmalloc_oob_16(struct kunit *test) 
		u64 words[2];

	} *ptr1, *ptr2;



	/* This test is specifically crafted for the generic mode. */

	if (!IS_ENABLED(CONFIG_KASAN_GENERIC)) {

		kunit_info(test, "CONFIG_KASAN_GENERIC required\n");

		return;

	}



	ptr1 = kmalloc(sizeof(*ptr1) - 3, GFP_KERNEL);

	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr1);
@@ -227,6 +233,23 @@ static void kmalloc_oob_16(struct kunit *test) 
	kfree(ptr2);

}



static void kmalloc_uaf_16(struct kunit *test)

{

	struct {

		u64 words[2];

	} *ptr1, *ptr2;



	ptr1 = kmalloc(sizeof(*ptr1), GFP_KERNEL);

	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr1);



	ptr2 = kmalloc(sizeof(*ptr2), GFP_KERNEL);

	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr2);

	kfree(ptr2);



	KUNIT_EXPECT_KASAN_FAIL(test, *ptr1 = *ptr2);

	kfree(ptr1);

}



static void kmalloc_oob_memset_2(struct kunit *test)

{

	char *ptr;
@@ -429,6 +452,12 @@ static void kasan_global_oob(struct kunit *test) 
	volatile int i = 3;

	char *p = &global_array[ARRAY_SIZE(global_array) + i];



	/* Only generic mode instruments globals. */

	if (!IS_ENABLED(CONFIG_KASAN_GENERIC)) {

		kunit_info(test, "CONFIG_KASAN_GENERIC required");

		return;

	}



	KUNIT_EXPECT_KASAN_FAIL(test, *(volatile char *)p);

}
@@ -467,6 +496,12 @@ static void kasan_alloca_oob_left(struct kunit *test) 
	char alloca_array[i];

	char *p = alloca_array - 1;



	/* Only generic mode instruments dynamic allocas. */

	if (!IS_ENABLED(CONFIG_KASAN_GENERIC)) {

		kunit_info(test, "CONFIG_KASAN_GENERIC required");

		return;

	}



	if (!IS_ENABLED(CONFIG_KASAN_STACK)) {

		kunit_info(test, "CONFIG_KASAN_STACK is not enabled");

		return;
@@ -481,6 +516,12 @@ static void kasan_alloca_oob_right(struct kunit *test) 
	char alloca_array[i];

	char *p = alloca_array + i;



	/* Only generic mode instruments dynamic allocas. */

	if (!IS_ENABLED(CONFIG_KASAN_GENERIC)) {

		kunit_info(test, "CONFIG_KASAN_GENERIC required");

		return;

	}



	if (!IS_ENABLED(CONFIG_KASAN_STACK)) {

		kunit_info(test, "CONFIG_KASAN_STACK is not enabled");

		return;
@@ -551,6 +592,9 @@ static void kasan_memchr(struct kunit *test) 
		return;

	}



	if (OOB_TAG_OFF)

		size = round_up(size, OOB_TAG_OFF);



	ptr = kmalloc(size, GFP_KERNEL | __GFP_ZERO);

	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
@@ -573,6 +617,9 @@ static void kasan_memcmp(struct kunit *test) 
		return;

	}



	if (OOB_TAG_OFF)

		size = round_up(size, OOB_TAG_OFF);



	ptr = kmalloc(size, GFP_KERNEL | __GFP_ZERO);

	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);

	memset(arr, 0, sizeof(arr));
@@ -619,13 +666,50 @@ static void kasan_strings(struct kunit *test) 
	KUNIT_EXPECT_KASAN_FAIL(test, kasan_int_result = strnlen(ptr, 1));

}



static void kasan_bitops(struct kunit *test)

static void kasan_bitops_modify(struct kunit *test, int nr, void *addr)

{

	KUNIT_EXPECT_KASAN_FAIL(test, set_bit(nr, addr));

	KUNIT_EXPECT_KASAN_FAIL(test, __set_bit(nr, addr));

	KUNIT_EXPECT_KASAN_FAIL(test, clear_bit(nr, addr));

	KUNIT_EXPECT_KASAN_FAIL(test, __clear_bit(nr, addr));

	KUNIT_EXPECT_KASAN_FAIL(test, clear_bit_unlock(nr, addr));

	KUNIT_EXPECT_KASAN_FAIL(test, __clear_bit_unlock(nr, addr));

	KUNIT_EXPECT_KASAN_FAIL(test, change_bit(nr, addr));

	KUNIT_EXPECT_KASAN_FAIL(test, __change_bit(nr, addr));

}



static void kasan_bitops_test_and_modify(struct kunit *test, int nr, void *addr)

{

	KUNIT_EXPECT_KASAN_FAIL(test, test_and_set_bit(nr, addr));

	KUNIT_EXPECT_KASAN_FAIL(test, __test_and_set_bit(nr, addr));

	KUNIT_EXPECT_KASAN_FAIL(test, test_and_set_bit_lock(nr, addr));

	KUNIT_EXPECT_KASAN_FAIL(test, test_and_clear_bit(nr, addr));

	KUNIT_EXPECT_KASAN_FAIL(test, __test_and_clear_bit(nr, addr));

	KUNIT_EXPECT_KASAN_FAIL(test, test_and_change_bit(nr, addr));

	KUNIT_EXPECT_KASAN_FAIL(test, __test_and_change_bit(nr, addr));

	KUNIT_EXPECT_KASAN_FAIL(test, kasan_int_result = test_bit(nr, addr));



#if defined(clear_bit_unlock_is_negative_byte)

	KUNIT_EXPECT_KASAN_FAIL(test, kasan_int_result =

				clear_bit_unlock_is_negative_byte(nr, addr));

#endif

}



static void kasan_bitops_generic(struct kunit *test)

{

	long *bits;



	/* This test is specifically crafted for the generic mode. */

	if (!IS_ENABLED(CONFIG_KASAN_GENERIC)) {

		kunit_info(test, "CONFIG_KASAN_GENERIC required\n");

		return;

	}



	/*

	 * Allocate 1 more byte, which causes kzalloc to round up to 16-bytes;

	 * this way we do not actually corrupt other memory.

	 */

	long *bits = kzalloc(sizeof(*bits) + 1, GFP_KERNEL);

	bits = kzalloc(sizeof(*bits) + 1, GFP_KERNEL);

	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, bits);



	/*
@@ -633,55 +717,34 @@ static void kasan_bitops(struct kunit *test) 
	 * below accesses are still out-of-bounds, since bitops are defined to

	 * operate on the whole long the bit is in.

	 */

	KUNIT_EXPECT_KASAN_FAIL(test, set_bit(BITS_PER_LONG, bits));



	KUNIT_EXPECT_KASAN_FAIL(test, __set_bit(BITS_PER_LONG, bits));



	KUNIT_EXPECT_KASAN_FAIL(test, clear_bit(BITS_PER_LONG, bits));



	KUNIT_EXPECT_KASAN_FAIL(test, __clear_bit(BITS_PER_LONG, bits));



	KUNIT_EXPECT_KASAN_FAIL(test, clear_bit_unlock(BITS_PER_LONG, bits));



	KUNIT_EXPECT_KASAN_FAIL(test, __clear_bit_unlock(BITS_PER_LONG, bits));



	KUNIT_EXPECT_KASAN_FAIL(test, change_bit(BITS_PER_LONG, bits));



	KUNIT_EXPECT_KASAN_FAIL(test, __change_bit(BITS_PER_LONG, bits));

	kasan_bitops_modify(test, BITS_PER_LONG, bits);



	/*

	 * Below calls try to access bit beyond allocated memory.

	 */

	KUNIT_EXPECT_KASAN_FAIL(test,

		test_and_set_bit(BITS_PER_LONG + BITS_PER_BYTE, bits));



	KUNIT_EXPECT_KASAN_FAIL(test,

		__test_and_set_bit(BITS_PER_LONG + BITS_PER_BYTE, bits));



	KUNIT_EXPECT_KASAN_FAIL(test,

		test_and_set_bit_lock(BITS_PER_LONG + BITS_PER_BYTE, bits));

	kasan_bitops_test_and_modify(test, BITS_PER_LONG + BITS_PER_BYTE, bits);



	KUNIT_EXPECT_KASAN_FAIL(test,

		test_and_clear_bit(BITS_PER_LONG + BITS_PER_BYTE, bits));

	kfree(bits);

}



	KUNIT_EXPECT_KASAN_FAIL(test,

		__test_and_clear_bit(BITS_PER_LONG + BITS_PER_BYTE, bits));

static void kasan_bitops_tags(struct kunit *test)

{

	long *bits;



	KUNIT_EXPECT_KASAN_FAIL(test,

		test_and_change_bit(BITS_PER_LONG + BITS_PER_BYTE, bits));

	/* This test is specifically crafted for the tag-based mode. */

	if (IS_ENABLED(CONFIG_KASAN_GENERIC)) {

		kunit_info(test, "CONFIG_KASAN_SW_TAGS required\n");

		return;

	}



	KUNIT_EXPECT_KASAN_FAIL(test,

		__test_and_change_bit(BITS_PER_LONG + BITS_PER_BYTE, bits));

	/* Allocation size will be rounded to up granule size, which is 16. */

	bits = kzalloc(sizeof(*bits), GFP_KERNEL);

	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, bits);



	KUNIT_EXPECT_KASAN_FAIL(test,

		kasan_int_result =

			test_bit(BITS_PER_LONG + BITS_PER_BYTE, bits));

	/* Do the accesses past the 16 allocated bytes. */

	kasan_bitops_modify(test, BITS_PER_LONG, &bits[1]);

	kasan_bitops_test_and_modify(test, BITS_PER_LONG + BITS_PER_BYTE, &bits[1]);



#if defined(clear_bit_unlock_is_negative_byte)

	KUNIT_EXPECT_KASAN_FAIL(test,

		kasan_int_result = clear_bit_unlock_is_negative_byte(

			BITS_PER_LONG + BITS_PER_BYTE, bits));

#endif

	kfree(bits);

}
@@ -728,6 +791,7 @@ static struct kunit_case kasan_kunit_test_cases[] = { 
	KUNIT_CASE(kmalloc_oob_krealloc_more),

	KUNIT_CASE(kmalloc_oob_krealloc_less),

	KUNIT_CASE(kmalloc_oob_16),

	KUNIT_CASE(kmalloc_uaf_16),

	KUNIT_CASE(kmalloc_oob_in_memset),

	KUNIT_CASE(kmalloc_oob_memset_2),

	KUNIT_CASE(kmalloc_oob_memset_4),
@@ -751,7 +815,8 @@ static struct kunit_case kasan_kunit_test_cases[] = { 
	KUNIT_CASE(kasan_memchr),

	KUNIT_CASE(kasan_memcmp),

	KUNIT_CASE(kasan_strings),

	KUNIT_CASE(kasan_bitops),

	KUNIT_CASE(kasan_bitops_generic),

	KUNIT_CASE(kasan_bitops_tags),

	KUNIT_CASE(kmalloc_double_kzfree),

	KUNIT_CASE(vmalloc_oob),

	{}

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