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From:   Nick Desaulniers <ndesaulniers@google.com>
Date:   Tue, 16 Jul 2019 12:45:25 -0700
Message-ID: <CAKwvOd=r3xh+yxCgFqQObwi=sMb9oqG0UcTvNJQ4KWKvN82g8A@mail.gmail.com>
Subject: Re: BUG: KASAN: global-out-of-bounds in ata_exec_internal_sg+0x50f/0xc70
To:     Steven Rostedt <rostedt@goodmis.org>
Cc:     Jeffrin Thalakkottoor <jeffrin@rajagiritech.edu.in>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        tobin@kernel.org, lkml <linux-kernel@vger.kernel.org>,
        Kees Cook <keescook@chromium.org>,
        Dmitry Vyukov <dvyukov@google.com>,
        Alexander Potapenko <glider@google.com>
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On Tue, Jul 16, 2019 at 11:57 AM Steven Rostedt <rostedt@goodmis.org> wrote:
>
> On Tue, 16 Jul 2019 11:28:29 -0700
> Nick Desaulniers <ndesaulniers@google.com> wrote:
>
> > The cited code looks like a check comparing that the pointer distance
> > is greater than the size of bytes being passed in.  I'd wager
> > someone's calling memmove with overlapping memory regions when they
> > really wanted memcpy.  Maybe a better question, is why was memmove
> > ever used; if there was some invariant that the memory regions
> > overlapped, why is that invariant no longer holding.
>
> I'm confused by the above statement as memmove() allows overlapping of
> src and dest, where as memcpy() does not.

Yes you're right; I confused the two.  From the snippet in the
original email, it looks like the body of a fortified memcpy was
provided, and a memmove declaration was below it.  So replace my
assumption of a bad call to memmove with a bad call to memcpy (which
should then make more sense, hopefully).
-- 
Thanks,
~Nick Desaulniers