From: andrey.konovalov@linux.dev
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrey Konovalov <andreyknvl@gmail.com>,
Andrey Ryabinin <aryabinin@virtuozzo.com>,
Marco Elver <elver@google.com>,
Dmitry Vyukov <dvyukov@google.com>,
Alexander Potapenko <glider@google.com>,
kasan-dev@googlegroups.com, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: [PATCH v2 3/8] kasan: test: avoid corrupting memory via memset
Date: Thu, 12 Aug 2021 16:53:30 +0200 [thread overview]
Message-ID: <64fd457668a16e7b58d094f14a165f9d5170c5a9.1628779805.git.andreyknvl@gmail.com> (raw)
In-Reply-To: <cover.1628779805.git.andreyknvl@gmail.com>
From: Andrey Konovalov <andreyknvl@gmail.com>
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.
Signed-off-by: Andrey Konovalov <andreyknvl@gmail.com>
---
lib/test_kasan.c | 28 +++++++++++++++++-----------
1 file changed, 17 insertions(+), 11 deletions(-)
diff --git a/lib/test_kasan.c b/lib/test_kasan.c
index c82a82eb5393..db73bc9e3fa2 100644
--- a/lib/test_kasan.c
+++ b/lib/test_kasan.c
@@ -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);
}
--
2.25.1
next prev parent reply other threads:[~2021-08-12 14:54 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-12 14:53 [PATCH v2 0/8] kasan: test: avoid crashing the kernel with HW_TAGS andrey.konovalov
2021-08-12 14:53 ` [PATCH v2 1/8] kasan: test: rework kmalloc_oob_right andrey.konovalov
2021-08-12 14:53 ` [PATCH v2 2/8] kasan: test: avoid writing invalid memory andrey.konovalov
2021-08-12 14:53 ` andrey.konovalov [this message]
2021-08-12 14:53 ` [PATCH v2 4/8] kasan: test: disable kmalloc_memmove_invalid_size for HW_TAGS andrey.konovalov
2021-08-12 14:53 ` [PATCH v2 5/8] kasan: test: only do kmalloc_uaf_memset for generic mode andrey.konovalov
2021-08-12 14:56 ` [PATCH v2 6/8] kasan: test: clean up ksize_uaf andrey.konovalov
2021-08-12 15:00 ` [PATCH v2 7/8] kasan: test: avoid corrupting memory in copy_user_test andrey.konovalov
2021-08-12 15:05 ` [PATCH v2 8/8] kasan: test: avoid corrupting memory in kasan_rcu_uaf andrey.konovalov
2021-08-12 15:05 ` [PATCH v2 0/8] kasan: test: avoid crashing the kernel with HW_TAGS Andrey Konovalov
2021-08-12 15:44 ` Marco Elver
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