kasan: add test for invalid size in memmove

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.

[walter-zh.wu@mediatek.com: fix -Wstringop-overflow warning]
Link: http://lkml.kernel.org/r/20200311134244.13016-1-walter-zh.wu@mediatek.com
Signed-off-by: Walter Wu <walter-zh.wu@mediatek.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: kernel test robot <lkp@intel.com>
Link: http://lkml.kernel.org/r/20191112065313.7060-1-walter-zh.wu@mediatek.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/lib/test_kasan.c b/lib/test_kasan.c
index 3872d25..e3087d9 100644 (file)
--- a/lib/test_kasan.c
+++ b/lib/test_kasan.c
@@ -285,6 +285,24 @@ 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;
+       volatile size_t invalid_size = -2;
+
+       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, invalid_size);
+       kfree(ptr);
+}
+
 static noinline void __init kmalloc_uaf(void)
 {
        char *ptr;
@@ -799,6 +817,7 @@ 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();