[PATCH AUTOSEL 5.14 96/99] kasan: test: only do kmalloc_uaf_memset for generic mode

Sasha Levin
2021-09-10T00:47:01Z

From: Andrey Konovalov <andreyknvl@gmail.com>

[ Upstream commit 25b12a58e848459ae2dbf2e7d318ef168bd1c5e2 ]

kmalloc_uaf_memset() writes to freed memory, which is only safe with the
GENERIC mode (as it uses quarantine). For other modes, this test corrupts
kernel memory, which might result in a crash.

Only enable kmalloc_uaf_memset() for the GENERIC mode.

Link: https://lkml.kernel.org/r/2e1c87b607b1292556cde3cab2764f108542b60c.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 | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/lib/test_kasan.c b/lib/test_kasan.c
index c149675300bd..65adde0757a3 100644
--- a/lib/test_kasan.c
+++ b/lib/test_kasan.c
@@ -518,6 +518,12 @@ static void kmalloc_uaf_memset(struct kunit *test)
char *ptr;
size_t size = 33;

+ /*
+ * Only generic KASAN uses quarantine, which is required to avoid a
+ * kernel memory corruption this test causes.
+ */
+ KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_GENERIC);
+
ptr = kmalloc(size, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);

--
2.30.2