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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 5/8] kasan: test: only do kmalloc_uaf_memset for generic mode
Date:   Thu, 12 Aug 2021 16:53:32 +0200
Message-Id: <2e1c87b607b1292556cde3cab2764f108542b60c.1628779805.git.andreyknvl@gmail.com>
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From: Andrey Konovalov <andreyknvl@gmail.com>

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.

Signed-off-by: Andrey Konovalov <andreyknvl@gmail.com>
---
 lib/test_kasan.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/lib/test_kasan.c b/lib/test_kasan.c
index 1f533a7346d9..1dcba6dbfc97 100644
--- a/lib/test_kasan.c
+++ b/lib/test_kasan.c
@@ -534,6 +534,12 @@ 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);
 
-- 
2.25.1