Commit 858bdeb0 authored by Andrey Konovalov's avatar Andrey Konovalov Committed by Linus Torvalds
Browse files

kasan: add proper page allocator tests 

The currently existing page allocator tests rely on kmalloc fallback
with large sizes that is only present for SLUB. Add proper tests that
use alloc/free_pages().

Link: https://linux-review.googlesource.com/id/Ia173d5a1b215fe6b2548d814ef0f4433cf983570
Link: https://lkml.kernel.org/r/a2648930e55ff75b8e700f2e0d905c2b55a67483.1610733117.git.andreyknvl@google.com


Signed-off-by: default avatarAndrey Konovalov <andreyknvl@google.com>
Reviewed-by: default avatarMarco Elver <elver@google.com>
Reviewed-by: default avatarAlexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Branislav Rankov <Branislav.Rankov@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Peter Collingbourne <pcc@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 611806b4

lib/test_kasan.c

+46 −5
Original line number Diff line number Diff line
@@ -147,6 +147,12 @@ static void kmalloc_node_oob_right(struct kunit *test) 
	kfree(ptr);

}



/*

 * These kmalloc_pagealloc_* tests try allocating a memory chunk that doesn't

 * fit into a slab cache and therefore is allocated via the page allocator

 * fallback. Since this kind of fallback is only implemented for SLUB, these

 * tests are limited to that allocator.

 */

static void kmalloc_pagealloc_oob_right(struct kunit *test)

{

	char *ptr;
@@ -154,14 +160,11 @@ static void kmalloc_pagealloc_oob_right(struct kunit *test) 


	KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_SLUB);



	/*

	 * Allocate a chunk that does not fit into a SLUB cache to trigger

	 * the page allocator fallback.

	 */

	ptr = kmalloc(size, GFP_KERNEL);

	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);



	KUNIT_EXPECT_KASAN_FAIL(test, ptr[size + OOB_TAG_OFF] = 0);



	kfree(ptr);

}
@@ -174,8 +177,8 @@ static void kmalloc_pagealloc_uaf(struct kunit *test) 


	ptr = kmalloc(size, GFP_KERNEL);

	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);



	kfree(ptr);



	KUNIT_EXPECT_KASAN_FAIL(test, ptr[0] = 0);

}
@@ -192,6 +195,42 @@ static void kmalloc_pagealloc_invalid_free(struct kunit *test) 
	KUNIT_EXPECT_KASAN_FAIL(test, kfree(ptr + 1));

}



static void pagealloc_oob_right(struct kunit *test)

{

	char *ptr;

	struct page *pages;

	size_t order = 4;

	size_t size = (1UL << (PAGE_SHIFT + order));



	/*

	 * With generic KASAN page allocations have no redzones, thus

	 * out-of-bounds detection is not guaranteed.

	 * See https://bugzilla.kernel.org/show_bug.cgi?id=210503.

	 */

	KASAN_TEST_NEEDS_CONFIG_OFF(test, CONFIG_KASAN_GENERIC);



	pages = alloc_pages(GFP_KERNEL, order);

	ptr = page_address(pages);

	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);



	KUNIT_EXPECT_KASAN_FAIL(test, ptr[size] = 0);

	free_pages((unsigned long)ptr, order);

}



static void pagealloc_uaf(struct kunit *test)

{

	char *ptr;

	struct page *pages;

	size_t order = 4;



	pages = alloc_pages(GFP_KERNEL, order);

	ptr = page_address(pages);

	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);

	free_pages((unsigned long)ptr, order);



	KUNIT_EXPECT_KASAN_FAIL(test, ptr[0] = 0);

}



static void kmalloc_large_oob_right(struct kunit *test)

{

	char *ptr;
@@ -903,6 +942,8 @@ static struct kunit_case kasan_kunit_test_cases[] = { 
	KUNIT_CASE(kmalloc_pagealloc_oob_right),

	KUNIT_CASE(kmalloc_pagealloc_uaf),

	KUNIT_CASE(kmalloc_pagealloc_invalid_free),

	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),