From: Kees Cook <keescook@chromium.org>
To: Kent Overstreet <kent.overstreet@linux.dev>
Cc: linux-bcachefs@vger.kernel.org, linux-bcache@vger.kernel.org,
Coly Li <colyli@suse.de>
Subject: Re: [PATCH] closures: CLOSURE_CALLBACK() to fix type punning
Date: Wed, 29 Nov 2023 12:13:16 -0800 [thread overview]
Message-ID: <202311291212.7955AF30D1@keescook> (raw)
In-Reply-To: <20231120030729.3285278-1-kent.overstreet@linux.dev>
On Sun, Nov 19, 2023 at 10:07:25PM -0500, Kent Overstreet wrote:
> Control flow integrity is now checking that type signatures match on
> indirect function calls. That breaks closures, which embed a work_struct
> in a closure in such a way that a closure_fn may also be used as a
> workqueue fn by the underlying closure code.
>
> So we have to change closure fns to take a work_struct as their
> argument - but that results in a loss of clarity, as closure fns have
> different semantics from normal workqueue functions (they run owning a
> ref on the closure, which must be released with continue_at() or
> closure_return()).
>
> Thus, this patc introduces CLOSURE_CALLBACK() and closure_type() macros
> as suggested by Kees, to smooth things over a bit.
>
> Suggested-by: Kees Cook <keescook@chromium.org>
> Cc: Coly Li <colyli@suse.de>
> Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Thanks for doing this! This looks reasonable to me. I look forward to
being able to do fancier CFI prototype partitioning in the future...
Reviewed-by: Kees Cook <keescook@chromium.org>
-Kees
--
Kees Cook
prev parent reply other threads:[~2023-11-29 20:13 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-20 3:07 [PATCH] closures: CLOSURE_CALLBACK() to fix type punning Kent Overstreet
2023-11-20 7:58 ` kernel test robot
2023-11-20 7:58 ` kernel test robot
2023-11-29 6:13 ` Coly Li
2023-11-29 20:13 ` Kees Cook [this message]
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