Re: [PATCH v2] Staging: rtl8723bs: Check sscanf return value

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Wed, Oct 18, 2017 at 12:39:11AM +0300, Georgiana Chelu wrote:
> Check the sscanf return value and handle it. The function returns
> the number of items of the argument list successfully filled.
> 
> Issue found by checkpatch.pl.
> WARNING: unchecked sscanf return value
> 
> Signed-off-by: Georgiana Chelu <georgiana.chelu93@gmail.com>
> ---
> 
> Changes in v2:
> * compared the return value of scanf to the right value
> * improved the commit message
> 
>  drivers/staging/rtl8723bs/os_dep/ioctl_linux.c | 11 +++++++++--
>  1 file changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/staging/rtl8723bs/os_dep/ioctl_linux.c b/drivers/staging/rtl8723bs/os_dep/ioctl_linux.c
> index 3fca0c2d4c8d..fe538cc088f0 100644
> --- a/drivers/staging/rtl8723bs/os_dep/ioctl_linux.c
> +++ b/drivers/staging/rtl8723bs/os_dep/ioctl_linux.c
> @@ -2356,7 +2356,11 @@ static int rtw_wx_read32(struct net_device *dev,
>  
>  	bytes = 0;
>  	addr = 0;
> -	sscanf(ptmp, "%d,%x", &bytes, &addr);
> +	ret = sscanf(ptmp, "%d,%x", &bytes, &addr);
> +	if (ret != 2) {
> +		ret = -EINVAL;
> +		goto exit;
> +	}

Are you sure that the code requires 2 values here?

>  
>  	switch (bytes) {
>  		case 1:
> @@ -2393,12 +2397,15 @@ static int rtw_wx_write32(struct net_device *dev,
>  	u32 addr;
>  	u32 data32;
>  	u32 bytes;
> +	int ret;
>  
>  
>  	bytes = 0;
>  	addr = 0;
>  	data32 = 0;
> -	sscanf(extra, "%d,%x,%x", &bytes, &addr, &data32);
> +	ret = sscanf(extra, "%d,%x,%x", &bytes, &addr, &data32);
> +	if (ret != 3)
> +		return -EINVAL;

Same here, are you sure that 3 values are required?

thanks,

greg k-h