[PATCH v2 2/2] kasan: add test for invalid size in memmove

[Walter Wu]

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...@mediatek.com>
Reviewed-by: Dmitry Vyukov <dvyu...@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