Re: [PATCH] wireless: rtlwifi: fix incorrect error codes in rtl_debugfs_set_write_rfreg()

[Simon Horman]

On Sat, Mar 25, 2023 at 08:34:29AM +0000, Wei Chen wrote:
> If there is a failure during copy_from_user or user-provided data buffer
> is invalid, rtl_debugfs_set_write_rfreg should return negative error code
> instead of a positive value count.
> 
> Fix this bug by returning correct error code. Moreover, the check of buffer
> against null is removed since it will be handled by copy_from_user.
> 
> Signed-off-by: Wei Chen <harperchen1110@xxxxxxxxx>

Hi Wei Chen,

* I'm not sure if a fixes tag is appropriate for this.
  But if so, perhaps it should be:

  Fixes: 610247f46feb ("rtlwifi: Improve debugging by using debugfs")

* I think the preferred subject prefix may be                                     'rtlwifi: ' (without the leading 'wireless: ').

* This seems to be v2 of this patch, which would be best noted in
  the subject '[PATCH v2]'.               

The above notwithstanding, the code changes look correct to me.

Reviewed-by: Simon Horman <simon.horman@xxxxxxxxxxxx>

> ---
>  drivers/net/wireless/realtek/rtlwifi/debug.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/net/wireless/realtek/rtlwifi/debug.c b/drivers/net/wireless/realtek/rtlwifi/debug.c
> index 3e7f9b4f1f19..9eb26dfe4ca9 100644
> --- a/drivers/net/wireless/realtek/rtlwifi/debug.c
> +++ b/drivers/net/wireless/realtek/rtlwifi/debug.c
> @@ -375,8 +375,8 @@ static ssize_t rtl_debugfs_set_write_rfreg(struct file *filp,
>  
>  	tmp_len = (count > sizeof(tmp) - 1 ? sizeof(tmp) - 1 : count);
>  
> -	if (!buffer || copy_from_user(tmp, buffer, tmp_len))
> -		return count;
> +	if (copy_from_user(tmp, buffer, tmp_len))
> +		return -EFAULT;
>  
>  	tmp[tmp_len] = '\0';
>  
> @@ -386,7 +386,7 @@ static ssize_t rtl_debugfs_set_write_rfreg(struct file *filp,
>  	if (num != 4) {
>  		rtl_dbg(rtlpriv, COMP_ERR, DBG_DMESG,
>  			"Format is <path> <addr> <mask> <data>\n");
> -		return count;
> +		return -EINVAL;
>  	}
>  
>  	rtl_set_rfreg(hw, path, addr, bitmask, data);
> -- 
> 2.25.1
>