From: Andrey Konovalov <andreyknvl@xxxxxxxxxx> Subject: 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. Link: https://lkml.kernel.org/r/76eee17b6531ca8b3ca92b240cb2fd23204aaff7.1603129942.git.andreyknvl@xxxxxxxxxx Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx> Tested-by: David Gow <davidgow@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- lib/test_kasan.c | 149 ++++++++++++++++++++++++++++++++------------- 1 file changed, 107 insertions(+), 42 deletions(-) --- a/lib/test_kasan.c~kasan-adopt-kunit-tests-to-sw_tags-mode +++ a/lib/test_kasan.c @@ -216,6 +216,12 @@ static void kmalloc_oob_16(struct kunit 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 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 kuni 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 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(struc 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 *t 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 *t 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 * 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 *t * 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)); + kasan_bitops_test_and_modify(test, BITS_PER_LONG + BITS_PER_BYTE, bits); - KUNIT_EXPECT_KASAN_FAIL(test, - test_and_set_bit_lock(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_tes 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_tes 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), {} _
