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

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

[Wei Chen]

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@gmail.com>
---
 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

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@gmail.com>

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@corigine.com>

> ---
>  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
> 

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

[Wei Chen]

Dear Simon,

Thanks for the advice and review. I have sent the second version of the patch.

Besides, rtl_debugfs_set_write_reg also suffers from the incorrect
error code problem. I also sent v2 of the corresponding patch. Hope
there is no confusion between these two patches.

Best,
Wei

On Sat, 25 Mar 2023 at 17:48, Simon Horman <simon.horman@corigine.com> wrote:
>
> 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@gmail.com>
>
> 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@corigine.com>
>
> > ---
> >  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
> >

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

[Simon Horman]

On Sun, Mar 26, 2023 at 01:47:51PM +0800, Wei Chen wrote:
> Dear Simon,
> 
> Thanks for the advice and review. I have sent the second version of the patch.
> 
> Besides, rtl_debugfs_set_write_reg also suffers from the incorrect
> error code problem. I also sent v2 of the corresponding patch. Hope
> there is no confusion between these two patches.

Thanks. I now see there are two similar but different patches. My bad.

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

[Larry Finger]

On 3/26/23 03:03, Simon Horman wrote:
> On Sun, Mar 26, 2023 at 01:47:51PM +0800, Wei Chen wrote:
>> Dear Simon,
>>
>> Thanks for the advice and review. I have sent the second version of the patch.
>>
>> Besides, rtl_debugfs_set_write_reg also suffers from the incorrect
>> error code problem. I also sent v2 of the corresponding patch. Hope
>> there is no confusion between these two patches.
> 
> Thanks. I now see there are two similar but different patches. My bad.

Avoid all such misunderstandings by making a patch set.

Larry