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kasan: test: avoid corrupting memory via memset 

kmalloc_oob_memset_*() tests do writes past the allocated objects.  As the
result, they corrupt memory, which might lead to crashes with the HW_TAGS
mode, as it neither uses quarantine nor redzones.

Adjust the tests to only write memory within the aligned kmalloc objects.

Also add a comment mentioning that memset tests are designed to touch both
valid and invalid memory.

Link: https://lkml.kernel.org/r/64fd457668a16e7b58d094f14a165f9d5170c5a9.1628779805.git.andreyknvl@gmail.com
Signed-off-by: Andrey Konovalov <andreyknvl@gmail.com>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Andrey Konovalov 2021-09-02 14:57:38 -07:00 committed by Linus Torvalds
parent 8fbad19bdc
commit 555999a009
1 changed files with 17 additions and 11 deletions
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28
lib/test_kasan.c
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@ -428,64 +428,70 @@ static void kmalloc_uaf_16(struct kunit *test)
kfree(ptr1);
}
/*
* Note: in the memset tests below, the written range touches both valid and
* invalid memory. This makes sure that the instrumentation does not only check
* the starting address but the whole range.
*/
static void kmalloc_oob_memset_2(struct kunit *test)
{
char *ptr;
size_t size = 8;
size_t size = 128 - KASAN_GRANULE_SIZE;
ptr = kmalloc(size, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
KUNIT_EXPECT_KASAN_FAIL(test, memset(ptr + 7 + OOB_TAG_OFF, 0, 2));
KUNIT_EXPECT_KASAN_FAIL(test, memset(ptr + size - 1, 0, 2));
kfree(ptr);
}
static void kmalloc_oob_memset_4(struct kunit *test)
{
char *ptr;
size_t size = 8;
size_t size = 128 - KASAN_GRANULE_SIZE;
ptr = kmalloc(size, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
KUNIT_EXPECT_KASAN_FAIL(test, memset(ptr + 5 + OOB_TAG_OFF, 0, 4));
KUNIT_EXPECT_KASAN_FAIL(test, memset(ptr + size - 3, 0, 4));
kfree(ptr);
}
static void kmalloc_oob_memset_8(struct kunit *test)
{
char *ptr;
size_t size = 8;
size_t size = 128 - KASAN_GRANULE_SIZE;
ptr = kmalloc(size, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
KUNIT_EXPECT_KASAN_FAIL(test, memset(ptr + 1 + OOB_TAG_OFF, 0, 8));
KUNIT_EXPECT_KASAN_FAIL(test, memset(ptr + size - 7, 0, 8));
kfree(ptr);
}
static void kmalloc_oob_memset_16(struct kunit *test)
{
char *ptr;
size_t size = 16;
size_t size = 128 - KASAN_GRANULE_SIZE;
ptr = kmalloc(size, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
KUNIT_EXPECT_KASAN_FAIL(test, memset(ptr + 1 + OOB_TAG_OFF, 0, 16));
KUNIT_EXPECT_KASAN_FAIL(test, memset(ptr + size - 15, 0, 16));
kfree(ptr);
}
static void kmalloc_oob_in_memset(struct kunit *test)
{
char *ptr;
size_t size = 666;
size_t size = 128 - KASAN_GRANULE_SIZE;
ptr = kmalloc(size, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
KUNIT_EXPECT_KASAN_FAIL(test, memset(ptr, 0, size + 5 + OOB_TAG_OFF));
KUNIT_EXPECT_KASAN_FAIL(test,
memset(ptr, 0, size + KASAN_GRANULE_SIZE));
kfree(ptr);
}