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From:   Walter Wu <walter-zh.wu@mediatek.com>
To:     Andrey Ryabinin <aryabinin@virtuozzo.com>,
        Alexander Potapenko <glider@google.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Matthias Brugger <matthias.bgg@gmail.com>
CC:     <kasan-dev@googlegroups.com>, <linux-mm@kvack.org>,
        <linux-kernel@vger.kernel.org>,
        <linux-arm-kernel@lists.infradead.org>,
        <linux-mediatek@lists.infradead.org>, <wsd_upstream@mediatek.com>,
        Walter Wu <walter-zh.wu@mediatek.com>
Subject: [PATCH v2 2/2] kasan: add test for invalid size in memmove
Date:   Tue, 15 Oct 2019 13:02:30 +0800
Message-ID: <20191015050230.20521-1-walter-zh.wu@mediatek.com>
MIME-Version: 1.0
Content-Type: text/plain
Sender: linux-kernel-owner@vger.kernel.org
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Test negative size in memmove in order to verify whether it correctly
get KASAN report.

Casting negative numbers to size_t would indeed turn up as a 'large'
size_t, so it will have out-of-bounds bug and detected by KASAN.

Changes in v2:
Add some descriptions for clarity the testcase.

Signed-off-by: Walter Wu <walter-zh.wu@mediatek.com>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
---
 lib/test_kasan.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/lib/test_kasan.c b/lib/test_kasan.c
index 49cc4d570a40..06942cf585cc 100644
--- a/lib/test_kasan.c
+++ b/lib/test_kasan.c
@@ -283,6 +283,23 @@ static noinline void __init kmalloc_oob_in_memset(void)
 	kfree(ptr);
 }
 
+static noinline void __init kmalloc_memmove_invalid_size(void)
+{
+	char *ptr;
+	size_t size = 64;
+
+	pr_info("invalid size in memmove\n");
+	ptr = kmalloc(size, GFP_KERNEL);
+	if (!ptr) {
+		pr_err("Allocation failed\n");
+		return;
+	}
+
+	memset((char *)ptr, 0, 64);
+	memmove((char *)ptr, (char *)ptr + 4, -2);
+	kfree(ptr);
+}
+
 static noinline void __init kmalloc_uaf(void)
 {
 	char *ptr;
@@ -773,6 +790,7 @@ static int __init kmalloc_tests_init(void)
 	kmalloc_oob_memset_4();
 	kmalloc_oob_memset_8();
 	kmalloc_oob_memset_16();
+	kmalloc_memmove_invalid_size();
 	kmalloc_uaf();
 	kmalloc_uaf_memset();
 	kmalloc_uaf2();
-- 
2.18.0