Re: [PATCH] kasan: fix the missing underflow in memmove and memcpy with CONFIG_KASAN_GENERIC=y

From: Walter Wu
Date: Tue Oct 08 2019 - 07:02:14 EST

On Tue, 2019-10-08 at 05:47 -0400, Qian Cai wrote:
> > On Oct 8, 2019, at 2:16 AM, Walter Wu <walter-zh.wu@xxxxxxxxxxxx> wrote:
> >
> > It is an undefined behavior to pass a negative numbers to
> > memset()/memcpy()/memmove(), so need to be detected by KASAN.
> Why canât this be detected by UBSAN?

I don't know very well in UBSAN, but I try to build ubsan kernel and
test a negative number in memset and kmalloc_memmove_invalid_size(), it
look like no check.