[PATCH AUTOSEL 5.14 97/99] kasan: test: clean up ksize_uaf

Sasha Levin
2021-09-10T00:47:06Z

From: Andrey Konovalov <andreyknvl@gmail.com>

[ Upstream commit b38fcca339dbcf680c9e43054502608fabc81508 ]

Some KASAN tests use global variables to store function returns values so
that the compiler doesn't optimize away these functions.

ksize_uaf() doesn't call any functions, so it doesn't need to use
kasan_int_result. Use volatile accesses instead, to be consistent with
other similar tests.

Link: https://lkml.kernel.org/r/a1fc34faca4650f4a6e4dfb3f8d8d82c82eb953a.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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
lib/test_kasan.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/test_kasan.c b/lib/test_kasan.c
index 65adde0757a3..564bee50cfa8 100644
--- a/lib/test_kasan.c
+++ b/lib/test_kasan.c
@@ -721,8 +721,8 @@ static void ksize_uaf(struct kunit *test)
kfree(ptr);

KUNIT_EXPECT_KASAN_FAIL(test, ksize(ptr));
- KUNIT_EXPECT_KASAN_FAIL(test, kasan_int_result = *ptr);
- KUNIT_EXPECT_KASAN_FAIL(test, kasan_int_result = *(ptr + size));
+ KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)ptr)[0]);
+ KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)ptr)[size]);
}

static void kasan_stack_oob(struct kunit *test)
--
2.30.2