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From:   Linus Torvalds <torvalds@linux-foundation.org>
Date:   Fri, 22 Sep 2023 16:55:45 -0700
Message-ID: <CAHk-=wg0C+eEm0Tegpvc1zZjcqkdG9L0ed10tg_rQ1-WZciMGA@mail.gmail.com>
Subject: Re: [GIT PULL] hardening fixes for v6.6-rc3
To:     Kees Cook <keescook@chromium.org>
Cc:     linux-kernel@vger.kernel.org, Alexey Dobriyan <adobriyan@gmail.com>
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On Fri, 22 Sept 2023 at 09:59, Kees Cook <keescook@chromium.org> wrote:
>
> - Fix UAPI stddef.h to avoid C++-ism (Alexey Dobriyan)

Ugh. Did we really have to make two different versions of that define?

Ok, so C++ did something stupid wrt an empty struct. Fine.

But I think we could have still shared the same definition by just
using the same 'zero-sized array' trick, regardless of any 'empty
struct has a size in C++'.

IOW, wouldn't this just work universally, without any "two completely
different versions" hack?

#define __DECLARE_FLEX_ARRAY(TYPE, NAME)        \
        struct { \
                char __empty_ ## NAME[0]; \
                TYPE NAME[]; \
        }

I didn't test. I'm just hating on that '#ifdef __cplusplus'.

                   Linus