From: Walter Wu <walter-zh.wu@xxxxxxxxxxxx> Subject: 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@xxxxxxxxxxxx: fix -Wstringop-overflow warning] Link: http://lkml.kernel.org/r/20200311134244.13016-1-walter-zh.wu@xxxxxxxxxxxx Link: http://lkml.kernel.org/r/20191112065313.7060-1-walter-zh.wu@xxxxxxxxxxxx Signed-off-by: Walter Wu <walter-zh.wu@xxxxxxxxxxxx> Reviewed-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx> Reviewed-by: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx> Cc: Alexander Potapenko <glider@xxxxxxxxxx> Cc: kernel test robot <lkp@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- lib/test_kasan.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) --- a/lib/test_kasan.c~kasan-add-test-for-invalid-size-in-memmove +++ a/lib/test_kasan.c @@ -285,6 +285,24 @@ static noinline void __init kmalloc_oob_ 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(voi kmalloc_oob_memset_4(); kmalloc_oob_memset_8(); kmalloc_oob_memset_16(); + kmalloc_memmove_invalid_size(); kmalloc_uaf(); kmalloc_uaf_memset(); kmalloc_uaf2(); _
