Re: [PATCH] selftests/exec: Avoid future NULL argv execve warning

From: Alexey Dobriyan <adobriyan@gmail.com>
To: Kees Cook <keescook@chromium.org>
Cc: Eric Biederman <ebiederm@xmission.com>,
	Shuah Khan <shuah@kernel.org>,
	linux-kselftest@vger.kernel.org,
	Ariadne Conill <ariadne@dereferenced.org>,
	Michael Kerrisk <mtk.manpages@gmail.com>,
	Matthew Wilcox <willy@infradead.org>,
	Christian Brauner <brauner@kernel.org>,
	Rich Felker <dalias@libc.org>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-hardening@vger.kernel.org
Subject: Re: [PATCH] selftests/exec: Avoid future NULL argv execve warning
Date: Wed, 2 Feb 2022 18:13:39 +0300	[thread overview]
Message-ID: <Yfqfo0rbq/B/l6IP@localhost.localdomain> (raw)
In-Reply-To: <20220201000807.2453486-1-keescook@chromium.org>

On Mon, Jan 31, 2022 at 04:08:07PM -0800, Kees Cook wrote:
> Build actual argv for launching recursion test to avoid future warning
> about using an empty argv in execve().

> --- a/tools/testing/selftests/exec/recursion-depth.c
> +++ b/tools/testing/selftests/exec/recursion-depth.c
> @@ -24,8 +24,14 @@
>  #include <sys/mount.h>
>  #include <unistd.h>
>  
> +#define FILENAME "/tmp/1"
> +#define HASHBANG "#!" FILENAME "\n"
> +
>  int main(void)
>  {
> +	char * const argv[] = { FILENAME, NULL };
> +	int rv;

Can we move out of -Wdeclaration-after-statement mentality in tests at least?

> -	int rv = execve(FILENAME, NULL, NULL);
> +	rv = execve(FILENAME, argv, NULL);

	int rv = execve(FILENAME, (char*[]){FILENAME, NULL}, NULL);

is cleaner (and modern)!

>  	if (rv == -1 && errno == ELOOP) {
>  		return 0;
>  	}