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Date: Thu, 6 Feb 2025 13:34:35 -0800
From: Kees Cook <kees@kernel.org>
To: David Laight <david.laight.linux@gmail.com>
Cc: Suren Baghdasaryan <surenb@google.com>,
	Kent Overstreet <kent.overstreet@linux.dev>,
	Andy Shevchenko <andy@kernel.org>,
	Luc Van Oostenryck <luc.vanoostenryck@gmail.com>,
	Nathan Chancellor <nathan@kernel.org>,
	Nick Desaulniers <ndesaulniers@google.com>,
	Bill Wendling <morbo@google.com>,
	Justin Stitt <justinstitt@google.com>,
	Philipp Reisner <philipp.reisner@linbit.com>,
	Miguel Ojeda <ojeda@kernel.org>, linux-kernel@vger.kernel.org,
	linux-hardening@vger.kernel.org, llvm@lists.linux.dev
Subject: Re: [PATCH 2/3] compiler.h: Introduce __must_be_char_array()
Message-ID: <202502061333.302D4EA68@keescook>
References: <20250206175216.work.225-kees@kernel.org>
 <20250206181133.3450635-2-kees@kernel.org>
 <20250206195658.79231973@pumpkin>
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In-Reply-To: <20250206195658.79231973@pumpkin>

On Thu, Feb 06, 2025 at 07:56:58PM +0000, David Laight wrote:
> On Thu,  6 Feb 2025 10:11:29 -0800
> Kees Cook <kees@kernel.org> wrote:
> 
> > In preparation for adding stricter type checking to the str/mem*()
> > helpers, provide a way to check that a variable is a character array
> > via __must_be_char_array().
> > 
> ...
> > +#define __is_char_array(a)	(__is_array(a) && sizeof((a)[0]) == 1)
> > +#define __must_be_char_array(a)	__BUILD_BUG_ON_ZERO_MSG(!__is_char_array(a), \
> > +							"must be byte array")
> 
> If you are only checking the size, perhaps __is_byte_array() would
> be a better name.
> (You've even used 'byte' in the error message.)

Yeah, fair point. I went and forth on naming. Fixed for v2.

-- 
Kees Cook