[PATCH v4 2/2] kasan: add test for invalid size in memmove

From: Walter Wu
Date: Tue Nov 12 2019 - 01:53:28 EST


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 be detected by KASAN.

Signed-off-by: Walter Wu <walter-zh.wu@xxxxxxxxxxxx>
Reviewed-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
---
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