From: Andrey Konovalov Date: Fri, 26 Feb 2021 01:20:15 +0000 (-0800) Subject: kasan: rework krealloc tests X-Git-Tag: accepted/tizen/unified/20230118.172025~7728^2~43 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=b87c28b9a7ef64590943435ea59f40092f2376d5;p=platform%2Fkernel%2Flinux-rpi.git kasan: rework krealloc tests This patch reworks KASAN-KUnit tests for krealloc() to: 1. Check both slab and page_alloc based krealloc() implementations. 2. Allow at least one full granule to fit between old and new sizes for each KASAN mode, and check accesses to that granule accordingly. Link: https://lkml.kernel.org/r/c707f128a2bb9f2f05185d1eb52192cf179cf4fa.1612546384.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov Reviewed-by: Marco Elver Cc: Alexander Potapenko Cc: Andrey Ryabinin Cc: Branislav Rankov Cc: Catalin Marinas Cc: Dmitry Vyukov Cc: Evgenii Stepanov Cc: Kevin Brodsky Cc: Peter Collingbourne Cc: Vincenzo Frascino Cc: Will Deacon Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/lib/test_kasan.c b/lib/test_kasan.c index 2557630..e1bd1d1 100644 --- a/lib/test_kasan.c +++ b/lib/test_kasan.c @@ -252,11 +252,14 @@ static void kmalloc_large_oob_right(struct kunit *test) kfree(ptr); } -static void kmalloc_oob_krealloc_more(struct kunit *test) +static void krealloc_more_oob_helper(struct kunit *test, + size_t size1, size_t size2) { char *ptr1, *ptr2; - size_t size1 = 17; - size_t size2 = 19; + size_t middle; + + KUNIT_ASSERT_LT(test, size1, size2); + middle = size1 + (size2 - size1) / 2; ptr1 = kmalloc(size1, GFP_KERNEL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr1); @@ -264,15 +267,31 @@ static void kmalloc_oob_krealloc_more(struct kunit *test) ptr2 = krealloc(ptr1, size2, GFP_KERNEL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr2); - KUNIT_EXPECT_KASAN_FAIL(test, ptr2[size2 + OOB_TAG_OFF] = 'x'); + /* All offsets up to size2 must be accessible. */ + ptr2[size1 - 1] = 'x'; + ptr2[size1] = 'x'; + ptr2[middle] = 'x'; + ptr2[size2 - 1] = 'x'; + + /* Generic mode is precise, so unaligned size2 must be inaccessible. */ + if (IS_ENABLED(CONFIG_KASAN_GENERIC)) + KUNIT_EXPECT_KASAN_FAIL(test, ptr2[size2] = 'x'); + + /* For all modes first aligned offset after size2 must be inaccessible. */ + KUNIT_EXPECT_KASAN_FAIL(test, + ptr2[round_up(size2, KASAN_GRANULE_SIZE)] = 'x'); + kfree(ptr2); } -static void kmalloc_oob_krealloc_less(struct kunit *test) +static void krealloc_less_oob_helper(struct kunit *test, + size_t size1, size_t size2) { char *ptr1, *ptr2; - size_t size1 = 17; - size_t size2 = 15; + size_t middle; + + KUNIT_ASSERT_LT(test, size2, size1); + middle = size2 + (size1 - size2) / 2; ptr1 = kmalloc(size1, GFP_KERNEL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr1); @@ -280,10 +299,60 @@ static void kmalloc_oob_krealloc_less(struct kunit *test) ptr2 = krealloc(ptr1, size2, GFP_KERNEL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr2); - KUNIT_EXPECT_KASAN_FAIL(test, ptr2[size2 + OOB_TAG_OFF] = 'x'); + /* Must be accessible for all modes. */ + ptr2[size2 - 1] = 'x'; + + /* Generic mode is precise, so unaligned size2 must be inaccessible. */ + if (IS_ENABLED(CONFIG_KASAN_GENERIC)) + KUNIT_EXPECT_KASAN_FAIL(test, ptr2[size2] = 'x'); + + /* For all modes first aligned offset after size2 must be inaccessible. */ + KUNIT_EXPECT_KASAN_FAIL(test, + ptr2[round_up(size2, KASAN_GRANULE_SIZE)] = 'x'); + + /* + * For all modes all size2, middle, and size1 should land in separate + * granules and thus the latter two offsets should be inaccessible. + */ + KUNIT_EXPECT_LE(test, round_up(size2, KASAN_GRANULE_SIZE), + round_down(middle, KASAN_GRANULE_SIZE)); + KUNIT_EXPECT_LE(test, round_up(middle, KASAN_GRANULE_SIZE), + round_down(size1, KASAN_GRANULE_SIZE)); + KUNIT_EXPECT_KASAN_FAIL(test, ptr2[middle] = 'x'); + KUNIT_EXPECT_KASAN_FAIL(test, ptr2[size1 - 1] = 'x'); + KUNIT_EXPECT_KASAN_FAIL(test, ptr2[size1] = 'x'); + kfree(ptr2); } +static void krealloc_more_oob(struct kunit *test) +{ + krealloc_more_oob_helper(test, 201, 235); +} + +static void krealloc_less_oob(struct kunit *test) +{ + krealloc_less_oob_helper(test, 235, 201); +} + +static void krealloc_pagealloc_more_oob(struct kunit *test) +{ + /* page_alloc fallback in only implemented for SLUB. */ + KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_SLUB); + + krealloc_more_oob_helper(test, KMALLOC_MAX_CACHE_SIZE + 201, + KMALLOC_MAX_CACHE_SIZE + 235); +} + +static void krealloc_pagealloc_less_oob(struct kunit *test) +{ + /* page_alloc fallback in only implemented for SLUB. */ + KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_SLUB); + + krealloc_less_oob_helper(test, KMALLOC_MAX_CACHE_SIZE + 235, + KMALLOC_MAX_CACHE_SIZE + 201); +} + static void kmalloc_oob_16(struct kunit *test) { struct { @@ -977,8 +1046,10 @@ static struct kunit_case kasan_kunit_test_cases[] = { KUNIT_CASE(pagealloc_oob_right), KUNIT_CASE(pagealloc_uaf), KUNIT_CASE(kmalloc_large_oob_right), - KUNIT_CASE(kmalloc_oob_krealloc_more), - KUNIT_CASE(kmalloc_oob_krealloc_less), + KUNIT_CASE(krealloc_more_oob), + KUNIT_CASE(krealloc_less_oob), + KUNIT_CASE(krealloc_pagealloc_more_oob), + KUNIT_CASE(krealloc_pagealloc_less_oob), KUNIT_CASE(kmalloc_oob_16), KUNIT_CASE(kmalloc_uaf_16), KUNIT_CASE(kmalloc_oob_in_memset),