Re: [PATCH 01/11] staging: vc04_services: changen strncpy() to strscpy_pad()

From: Justin Stitt <justinstitt@google.com>
To: Arnd Bergmann <arnd@kernel.org>
Cc: linux-kernel@vger.kernel.org,
	 Florian Fainelli <florian.fainelli@broadcom.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	 Arnd Bergmann <arnd@arndb.de>,
	 Broadcom internal kernel review list
	<bcm-kernel-feedback-list@broadcom.com>,
	linux-rpi-kernel@lists.infradead.org,
	 linux-arm-kernel@lists.infradead.org,
	linux-staging@lists.linux.dev
Subject: Re: [PATCH 01/11] staging: vc04_services: changen strncpy() to strscpy_pad()
Date: Thu, 28 Mar 2024 23:10:44 +0000	[thread overview]
Message-ID: <hbwxiid52lv2dq7rdtvard3up46khu5uv335tzavwag3v6s6jl@dzjrnooz553m> (raw)
In-Reply-To: <20240328140512.4148825-2-arnd@kernel.org>

Hi,

On Thu, Mar 28, 2024 at 03:04:45PM +0100, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
> 
> gcc-14 warns about this strncpy() that results in a non-terminated
> string for an overflow:
> 
> In file included from include/linux/string.h:369,
>                  from drivers/staging/vc04_services/vchiq-mmal/mmal-vchiq.c:20:
> In function 'strncpy',
>     inlined from 'create_component' at drivers/staging/vc04_services/vchiq-mmal/mmal-vchiq.c:940:2:
> include/linux/fortify-string.h:108:33: error: '__builtin_strncpy' specified bound 128 equals destination size [-Werror=stringop-truncation]
> 
> Change it to strscpy_pad(), which produces a properly terminated and
> zero-padded string.
> 
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

If there is other review that warrants a change, we might as well switch
over to the new 2-argument version of strscpy{_pad}() introduced in
Commit e6584c3964f2f ("string: Allow 2-argument strscpy()"). No need to
change for only this reason, though.

Reviewed-by: Justin Stitt <justinstitt@google.com>

> ---
>  drivers/staging/vc04_services/vchiq-mmal/mmal-vchiq.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/staging/vc04_services/vchiq-mmal/mmal-vchiq.c b/drivers/staging/vc04_services/vchiq-mmal/mmal-vchiq.c
> index 258aa0e37f55..6ca5797aeae5 100644
> --- a/drivers/staging/vc04_services/vchiq-mmal/mmal-vchiq.c
> +++ b/drivers/staging/vc04_services/vchiq-mmal/mmal-vchiq.c
> @@ -937,8 +937,8 @@ static int create_component(struct vchiq_mmal_instance *instance,
>  	/* build component create message */
>  	m.h.type = MMAL_MSG_TYPE_COMPONENT_CREATE;
>  	m.u.component_create.client_component = component->client_component;
> -	strncpy(m.u.component_create.name, name,
> -		sizeof(m.u.component_create.name));
> +	strscpy_pad(m.u.component_create.name, name,
> +		    sizeof(m.u.component_create.name));
>  
>  	ret = send_synchronous_mmal_msg(instance, &m,
>  					sizeof(m.u.component_create),
> -- 
> 2.39.2
> 

Thanks
Justin