linux-kernel - Re: [PATCH 07/12] driver/char: use correct format characters

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Message-ID: <YqLUORmZQgG1D6lc@kroah.com>
Date:   Fri, 10 Jun 2022 07:18:49 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     Bill Wendling <morbo@...gle.com>
Cc:     isanbard@...il.com, Tony Luck <tony.luck@...el.com>,
        Borislav Petkov <bp@...en8.de>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org,
        "H. Peter Anvin" <hpa@...or.com>,
        Phillip Potter <phil@...lpotter.co.uk>,
        Arnd Bergmann <arnd@...db.de>,
        "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
        Jan Kara <jack@...e.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Pablo Neira Ayuso <pablo@...filter.org>,
        Jozsef Kadlecsik <kadlec@...filter.org>,
        Florian Westphal <fw@...len.de>,
        "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>,
        Jaroslav Kysela <perex@...ex.cz>,
        Takashi Iwai <tiwai@...e.com>,
        Nathan Chancellor <nathan@...nel.org>,
        Nick Desaulniers <ndesaulniers@...gle.com>,
        Tom Rix <trix@...hat.com>,
        Daniel Kiper <daniel.kiper@...cle.com>,
        Ross Philipson <ross.philipson@...cle.com>,
        linux-edac@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-acpi@...r.kernel.org, linux-mm@...ck.org,
        netfilter-devel@...r.kernel.org, coreteam@...filter.org,
        netdev@...r.kernel.org, alsa-devel@...a-project.org,
        llvm@...ts.linux.dev
Subject: Re: [PATCH 07/12] driver/char: use correct format characters

On Thu, Jun 09, 2022 at 10:16:26PM +0000, Bill Wendling wrote:
> From: Bill Wendling <isanbard@...il.com>

Why isn't that matching your From: line in the email?

> 
> When compiling with -Wformat, clang emits the following warnings:

Is that ever a default build option for the kernel?

> 
> drivers/char/mem.c:775:16: error: format string is not a string literal (potentially insecure) [-Werror,-Wformat-security]
>                               NULL, devlist[minor].name);
>                                     ^~~~~~~~~~~~~~~~~~~
> 
> Use a string literal for the format string.
> 
> Link: https://github.com/ClangBuiltLinux/linux/issues/378
> Signed-off-by: Bill Wendling <isanbard@...il.com>
> ---
>  drivers/char/mem.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/char/mem.c b/drivers/char/mem.c
> index 84ca98ed1dad..32d821ba9e4d 100644
> --- a/drivers/char/mem.c
> +++ b/drivers/char/mem.c
> @@ -772,7 +772,7 @@ static int __init chr_dev_init(void)
>  			continue;
>  
>  		device_create(mem_class, NULL, MKDEV(MEM_MAJOR, minor),
> -			      NULL, devlist[minor].name);
> +			      NULL, "%s", devlist[minor].name);

Please explain how this static string can ever be user controlled.

thanks,

greg k-h