[PATCH v2 26/28] video: fbdev: uvesafb: Fix string related warnings

[Thomas Zimmermann]

Hi

Am 28.11.20 um 23:41 schrieb Sam Ravnborg:
> Two W=1 string related warnings.
> - Using strncpy to copy string without null-termination generates a
>    warning.  Use memcpy to copy only the relevant chars
> 
> - Fix a potential bug with a very long string, subtract one from the
>    length to make room for the termination null.
> 
> Signed-off-by: Sam Ravnborg <sam at ravnborg.org>
> Cc: Michal Januszewski <spock at gentoo.org>
> Cc: linux-fbdev at vger.kernel.org
> ---
>   drivers/video/fbdev/uvesafb.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/video/fbdev/uvesafb.c b/drivers/video/fbdev/uvesafb.c
> index 8ee0fc9c63cf..45dc8da191e4 100644
> --- a/drivers/video/fbdev/uvesafb.c
> +++ b/drivers/video/fbdev/uvesafb.c
> @@ -423,7 +423,7 @@ static int uvesafb_vbe_getinfo(struct uvesafb_ktask *task,
>   	task->t.flags = TF_VBEIB;
>   	task->t.buf_len = sizeof(struct vbe_ib);
>   	task->buf = &par->vbe_ib;
> -	strncpy(par->vbe_ib.vbe_signature, "VBE2", 4);
> +	memcpy(par->vbe_ib.vbe_signature, "VBE2", 4);
>   
>   	err = uvesafb_exec(task);
>   	if (err || (task->t.regs.eax & 0xffff) != 0x004f) {
> @@ -1871,7 +1871,7 @@ static ssize_t v86d_show(struct device_driver *dev, char *buf)
>   static ssize_t v86d_store(struct device_driver *dev, const char *buf,
>   		size_t count)
>   {
> -	strncpy(v86d_path, buf, PATH_MAX);
> +	strncpy(v86d_path, buf, PATH_MAX - 1);

 From lookign a the drive rcode, I assume that the code never touches 
the final byte in v86d_path. So it remains \0 indefinitely.

Acked-by: Thomas Zimmermann <tzimmermann at suse.de>

>   	return count;
>   }
>   static DRIVER_ATTR_RW(v86d);
> 

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Felix Imendörffer

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