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Date:   Wed, 2 Nov 2022 15:02:44 -0700
From:   Kees Cook <keescook@chromium.org>
To:     Nathan Chancellor <nathan@kernel.org>
Cc:     William Breathitt Gray <william.gray@linaro.org>,
        linux-iio@vger.kernel.org,
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        linux-kernel@vger.kernel.org, patches@lists.linux.dev,
        Patrick Havelange <patrick.havelange@essensium.com>,
        Jarkko Nikula <jarkko.nikula@linux.intel.com>,
        Oleksij Rempel <linux@rempel-privat.de>,
        Pengutronix Kernel Team <kernel@pengutronix.de>,
        Fabrice Gasnier <fabrice.gasnier@foss.st.com>,
        Vignesh Raghavendra <vigneshr@ti.com>,
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Subject: Re: [PATCH 1/4] counter: Adjust final parameter type in function and
 signal callbacks
Message-ID: <202211021501.88D8147@keescook>
References: <20221102172217.2860740-1-nathan@kernel.org>
 <202211021216.FF49E84C69@keescook>
 <Y2LR13xrrauVmeXP@dev-arch.thelio-3990X>
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On Wed, Nov 02, 2022 at 01:23:51PM -0700, Nathan Chancellor wrote:
> Right, I am not the biggest fan of this change myself and it is entirely
> possible that I am misreading the warnings from the commit message but I
> do not see how
> 
>         comp_node.comp.signal_u32_read = counter->ops->signal_read;
> 
> and
> 
>         comp_node.comp.count_u32_read = counter->ops->function_read;
> 
> in counter_add_watch(),
> 
>         comp.signal_u32_read = counter->ops->signal_read;
> 
> in counter_signal_attrs_create(), and
> 
>         comp.count_u32_read = counter->ops->function_read;
>         comp.count_u32_write = counter->ops->function_write;
> 
> in counter_count_attrs_create() are currently safe under kCFI, since the
> final parameter type of the prototypes in 'struct counter_ops' does not
> match the final parameter type of the prototypes in 'struct
> counter_comp'. I would expect the indirect calls in counter_get_data()
> and counter_comp_u32_show() to fail currently.

Ah! Thank you -- those were the places I couldn't find.

-- 
Kees Cook