linux-kernel - Re: [PATCH -next] [media] media: Replaced simple

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Date:   Wed, 26 May 2021 12:08:41 +0200
From:   Hans Verkuil <hverkuil@...all.nl>
To:     Liu Shixin <liushixin2@...wei.com>, Mike Isely <isely@...ox.com>,
        Mauro Carvalho Chehab <mchehab@...nel.org>
Cc:     linux-media@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH -next] [media] media: Replaced simple_strtol() with
 kstrtoint()

On 24/05/2021 14:08, Liu Shixin wrote:
> It looks like that memcpy() is a superfluous operation in
> parse_token()/parse_mtoken(). Simple these two functions and
> use kstrtoint() instead of simple_strtol() to avoid data
> overflow.

Always mention which driver you are changing in the subject line.
Just saying 'media:' suggests a subsystem-wide patch, but this is
just for a single driver.

Regards,

	Hans

> 
> Signed-off-by: Liu Shixin <liushixin2@...wei.com>
> ---
>  drivers/media/usb/pvrusb2/pvrusb2-ctrl.c | 25 ++----------------------
>  1 file changed, 2 insertions(+), 23 deletions(-)
> 
> diff --git a/drivers/media/usb/pvrusb2/pvrusb2-ctrl.c b/drivers/media/usb/pvrusb2/pvrusb2-ctrl.c
> index 9f71d8c2a3c6..8ae3ad80cccb 100644
> --- a/drivers/media/usb/pvrusb2/pvrusb2-ctrl.c
> +++ b/drivers/media/usb/pvrusb2/pvrusb2-ctrl.c
> @@ -355,11 +355,8 @@ static int parse_token(const char *ptr,unsigned int len,
>  		       int *valptr,
>  		       const char * const *names, unsigned int namecnt)
>  {
> -	char buf[33];
>  	unsigned int slen;
>  	unsigned int idx;
> -	int negfl;
> -	char *p2;
>  	*valptr = 0;
>  	if (!names) namecnt = 0;
>  	for (idx = 0; idx < namecnt; idx++) {
> @@ -370,18 +367,7 @@ static int parse_token(const char *ptr,unsigned int len,
>  		*valptr = idx;
>  		return 0;
>  	}
> -	negfl = 0;
> -	if ((*ptr == '-') || (*ptr == '+')) {
> -		negfl = (*ptr == '-');
> -		ptr++; len--;
> -	}
> -	if (len >= sizeof(buf)) return -EINVAL;
> -	memcpy(buf,ptr,len);
> -	buf[len] = 0;
> -	*valptr = simple_strtol(buf,&p2,0);
> -	if (negfl) *valptr = -(*valptr);
> -	if (*p2) return -EINVAL;
> -	return 1;
> +	return kstrtoint(ptr, 0, valptr) ? -EINVAL : 1;
>  }
>  
>  
> @@ -389,10 +375,8 @@ static int parse_mtoken(const char *ptr,unsigned int len,
>  			int *valptr,
>  			const char **names,int valid_bits)
>  {
> -	char buf[33];
>  	unsigned int slen;
>  	unsigned int idx;
> -	char *p2;
>  	int msk;
>  	*valptr = 0;
>  	for (idx = 0, msk = 1; valid_bits; idx++, msk <<= 1) {
> @@ -405,12 +389,7 @@ static int parse_mtoken(const char *ptr,unsigned int len,
>  		*valptr = msk;
>  		return 0;
>  	}
> -	if (len >= sizeof(buf)) return -EINVAL;
> -	memcpy(buf,ptr,len);
> -	buf[len] = 0;
> -	*valptr = simple_strtol(buf,&p2,0);
> -	if (*p2) return -EINVAL;
> -	return 0;
> +	return kstrtoint(ptr, 0, valptr);
>  }
>  
>  
>