[PATCH] wifi: mt76: mt7996: prevent uninit return in mt7996_mac_sta_add_links

[PATCH] wifi: mt76: mt7996: prevent uninit return in mt7996_mac_sta_add_links

[Qasim Ijaz]

If link_conf_dereference_protected() or mt7996_vif_link() 
or link_sta_dereference_protected() fail the code jumps to
the error_unlink label and returns ret which is uninitialised.

Fix this by setting err before jumping to error_unlink.

Fixes: c7e4fc362443 ("wifi: mt76: mt7996: Update mt7996_mcu_add_sta to MLO support")
Fixes: dd82a9e02c05 ("wifi: mt76: mt7996: Rely on mt7996_sta_link in sta_add/sta_remove callbacks")
Signed-off-by: Qasim Ijaz <qasdev00@gmail.com>
---
 drivers/net/wireless/mediatek/mt76/mt7996/main.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7996/main.c b/drivers/net/wireless/mediatek/mt76/mt7996/main.c
index 91c64e3a0860..78f7f1fc867e 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7996/main.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7996/main.c
@@ -998,16 +998,22 @@ mt7996_mac_sta_add_links(struct mt7996_dev *dev, struct ieee80211_vif *vif,
 			continue;
 
 		link_conf = link_conf_dereference_protected(vif, link_id);
-		if (!link_conf)
+		if (!link_conf) {
+			err = -EINVAL;
 			goto error_unlink;
+		}
 
 		link = mt7996_vif_link(dev, vif, link_id);
-		if (!link)
+		if (!link) {
+			err = -EINVAL;
 			goto error_unlink;
+		}
 
 		link_sta = link_sta_dereference_protected(sta, link_id);
-		if (!link_sta)
+		if (!link_sta) {
+			err = -EINVAL
 			goto error_unlink;
+		}
 
 		err = mt7996_mac_sta_init_link(dev, link_conf, link_sta, link,
 					       link_id);
-- 
2.39.5

Re: [PATCH] wifi: mt76: mt7996: prevent uninit return in mt7996_mac_sta_add_links

[Dan Carpenter]

On Thu, Mar 20, 2025 at 08:19:14PM +0000, Qasim Ijaz wrote:
> If link_conf_dereference_protected() or mt7996_vif_link() 
> or link_sta_dereference_protected() fail the code jumps to
> the error_unlink label and returns ret which is uninitialised.
> 
> Fix this by setting err before jumping to error_unlink.
> 
> Fixes: c7e4fc362443 ("wifi: mt76: mt7996: Update mt7996_mcu_add_sta to MLO support")
> Fixes: dd82a9e02c05 ("wifi: mt76: mt7996: Rely on mt7996_sta_link in sta_add/sta_remove callbacks")
> Signed-off-by: Qasim Ijaz <qasdev00@gmail.com>
> ---
>  drivers/net/wireless/mediatek/mt76/mt7996/main.c | 12 +++++++++---
>  1 file changed, 9 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/net/wireless/mediatek/mt76/mt7996/main.c b/drivers/net/wireless/mediatek/mt76/mt7996/main.c
> index 91c64e3a0860..78f7f1fc867e 100644
> --- a/drivers/net/wireless/mediatek/mt76/mt7996/main.c
> +++ b/drivers/net/wireless/mediatek/mt76/mt7996/main.c
> @@ -998,16 +998,22 @@ mt7996_mac_sta_add_links(struct mt7996_dev *dev, struct ieee80211_vif *vif,
>  			continue;

What about if the list is empty or we hit this continue on every link?

regards,
dan carpenter

>  
>  		link_conf = link_conf_dereference_protected(vif, link_id);
> -		if (!link_conf)
> +		if (!link_conf) {
> +			err = -EINVAL;
>  			goto error_unlink;
> +		}
>  
>  		link = mt7996_vif_link(dev, vif, link_id);
> -		if (!link)
> +		if (!link) {
> +			err = -EINVAL;
>  			goto error_unlink;
> +		}
>  
>  		link_sta = link_sta_dereference_protected(sta, link_id);
> -		if (!link_sta)
> +		if (!link_sta) {
> +			err = -EINVAL
>  			goto error_unlink;
> +		}
>  
>  		err = mt7996_mac_sta_init_link(dev, link_conf, link_sta, link,
>  					       link_id);
> -- 
> 2.39.5
> 

Re: [PATCH] wifi: mt76: mt7996: prevent uninit return in mt7996_mac_sta_add_links

[Lorenzo Bianconi]

[-- Attachment #1: Type: text/plain, Size: 1976 bytes --]

> On Thu, Mar 20, 2025 at 08:19:14PM +0000, Qasim Ijaz wrote:
> > If link_conf_dereference_protected() or mt7996_vif_link() 
> > or link_sta_dereference_protected() fail the code jumps to
> > the error_unlink label and returns ret which is uninitialised.
> > 
> > Fix this by setting err before jumping to error_unlink.
> > 
> > Fixes: c7e4fc362443 ("wifi: mt76: mt7996: Update mt7996_mcu_add_sta to MLO support")
> > Fixes: dd82a9e02c05 ("wifi: mt76: mt7996: Rely on mt7996_sta_link in sta_add/sta_remove callbacks")
> > Signed-off-by: Qasim Ijaz <qasdev00@gmail.com>
> > ---
> >  drivers/net/wireless/mediatek/mt76/mt7996/main.c | 12 +++++++++---
> >  1 file changed, 9 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/net/wireless/mediatek/mt76/mt7996/main.c b/drivers/net/wireless/mediatek/mt76/mt7996/main.c
> > index 91c64e3a0860..78f7f1fc867e 100644
> > --- a/drivers/net/wireless/mediatek/mt76/mt7996/main.c
> > +++ b/drivers/net/wireless/mediatek/mt76/mt7996/main.c
> > @@ -998,16 +998,22 @@ mt7996_mac_sta_add_links(struct mt7996_dev *dev, struct ieee80211_vif *vif,
> >  			continue;
> 
> What about if the list is empty or we hit this continue on every link?

we will return 0 and I guess that's fine, agree?

Regards,
Lorenzo

> 
> regards,
> dan carpenter
> 
> >  
> >  		link_conf = link_conf_dereference_protected(vif, link_id);
> > -		if (!link_conf)
> > +		if (!link_conf) {
> > +			err = -EINVAL;
> >  			goto error_unlink;
> > +		}
> >  
> >  		link = mt7996_vif_link(dev, vif, link_id);
> > -		if (!link)
> > +		if (!link) {
> > +			err = -EINVAL;
> >  			goto error_unlink;
> > +		}
> >  
> >  		link_sta = link_sta_dereference_protected(sta, link_id);
> > -		if (!link_sta)
> > +		if (!link_sta) {
> > +			err = -EINVAL
> >  			goto error_unlink;
> > +		}
> >  
> >  		err = mt7996_mac_sta_init_link(dev, link_conf, link_sta, link,
> >  					       link_id);
> > -- 
> > 2.39.5
> > 

[-- Attachment #2: signature.asc --]
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Re: [PATCH] wifi: mt76: mt7996: prevent uninit return in mt7996_mac_sta_add_links

[Dan Carpenter]

On Fri, Mar 21, 2025 at 06:14:49PM +0100, Lorenzo Bianconi wrote:
> > On Thu, Mar 20, 2025 at 08:19:14PM +0000, Qasim Ijaz wrote:
> > > If link_conf_dereference_protected() or mt7996_vif_link() 
> > > or link_sta_dereference_protected() fail the code jumps to
> > > the error_unlink label and returns ret which is uninitialised.
> > > 
> > > Fix this by setting err before jumping to error_unlink.
> > > 
> > > Fixes: c7e4fc362443 ("wifi: mt76: mt7996: Update mt7996_mcu_add_sta to MLO support")
> > > Fixes: dd82a9e02c05 ("wifi: mt76: mt7996: Rely on mt7996_sta_link in sta_add/sta_remove callbacks")
> > > Signed-off-by: Qasim Ijaz <qasdev00@gmail.com>
> > > ---
> > >  drivers/net/wireless/mediatek/mt76/mt7996/main.c | 12 +++++++++---
> > >  1 file changed, 9 insertions(+), 3 deletions(-)
> > > 
> > > diff --git a/drivers/net/wireless/mediatek/mt76/mt7996/main.c b/drivers/net/wireless/mediatek/mt76/mt7996/main.c
> > > index 91c64e3a0860..78f7f1fc867e 100644
> > > --- a/drivers/net/wireless/mediatek/mt76/mt7996/main.c
> > > +++ b/drivers/net/wireless/mediatek/mt76/mt7996/main.c
> > > @@ -998,16 +998,22 @@ mt7996_mac_sta_add_links(struct mt7996_dev *dev, struct ieee80211_vif *vif,
> > >  			continue;
> > 
> > What about if the list is empty or we hit this continue on every link?
> 
> we will return 0 and I guess that's fine, agree?
> 

Fine by me?

regards,
dan carpenter

Re: [PATCH] wifi: mt76: mt7996: prevent uninit return in mt7996_mac_sta_add_links

[Markus Elfring]

…
> +++ b/drivers/net/wireless/mediatek/mt76/mt7996/main.c
> @@ -998,16 +998,22 @@ mt7996_mac_sta_add_links(struct mt7996_dev *dev, struct ieee80211_vif *vif,
>  			continue;
>
>  		link_conf = link_conf_dereference_protected(vif, link_id);
> -		if (!link_conf)
> +		if (!link_conf) {
> +			err = -EINVAL;
>  			goto error_unlink;
> +		}
>
>  		link = mt7996_vif_link(dev, vif, link_id);
> -		if (!link)
> +		if (!link) {
> +			err = -EINVAL;
>  			goto error_unlink;
> +		}
…

I suggest to avoid such repeated error code assignments.
Can an additional label be applied instead for this purpose?

Regards,
Markus

Re: [PATCH] wifi: mt76: mt7996: prevent uninit return in mt7996_mac_sta_add_links

[Dan Carpenter]

On Sat, Mar 22, 2025 at 11:01:18AM +0100, Markus Elfring wrote:
> …
> > +++ b/drivers/net/wireless/mediatek/mt76/mt7996/main.c
> > @@ -998,16 +998,22 @@ mt7996_mac_sta_add_links(struct mt7996_dev *dev, struct ieee80211_vif *vif,
> >  			continue;
> >
> >  		link_conf = link_conf_dereference_protected(vif, link_id);
> > -		if (!link_conf)
> > +		if (!link_conf) {
> > +			err = -EINVAL;
> >  			goto error_unlink;
> > +		}
> >
> >  		link = mt7996_vif_link(dev, vif, link_id);
> > -		if (!link)
> > +		if (!link) {
> > +			err = -EINVAL;
> >  			goto error_unlink;
> > +		}
> …
> 
> I suggest to avoid such repeated error code assignments.
> Can an additional label be applied instead for this purpose?

Maintainers get the final vote but generally when someone is doing
the work they get to decide.

I would say that generally the way that Qasim did it is normally
more readable and more future proof.

regards
dan carpenter

Re: [PATCH] wifi: mt76: mt7996: prevent uninit return in mt7996_mac_sta_add_links

[Johannes Berg]

On Sat, 2025-03-22 at 11:01 +0100, Markus Elfring wrote:
> 
> I suggest to avoid such repeated error code assignments.
> Can an additional label be applied instead for this purpose?
> 

Please stop your "suggestions" on this list. None have really been
helpful.

johannes

Re: wifi: mt76: mt7996: prevent uninit return in mt7996_mac_sta_add_links

[Markus Elfring]

>> I suggest to avoid such repeated error code assignments.
>> Can an additional label be applied instead for this purpose?
>
> Please stop your "suggestions" on this list. None have really been
> helpful.
It seems that you care less then for the avoidance of duplicate source code
also for affected error/exception handling.

Regards,
Markus

Re: [PATCH] wifi: mt76: mt7996: prevent uninit return in mt7996_mac_sta_add_links

[Markus Elfring]

> If link_conf_dereference_protected() or mt7996_vif_link()
> or link_sta_dereference_protected() fail the code jumps to

                                      call failed?


> the error_unlink label and returns ret which is uninitialised.

                                     a value from a local variable
                                     which was not initialised properly?


Can the summary phrase be improved also another bit?

Regards,
Markus

Re: [PATCH] wifi: mt76: mt7996: prevent uninit return in mt7996_mac_sta_add_links

[Jonas Gorski]

Hi,

On Thu, Mar 20, 2025 at 9:19 PM Qasim Ijaz <qasdev00@gmail.com> wrote:
>
> If link_conf_dereference_protected() or mt7996_vif_link()
> or link_sta_dereference_protected() fail the code jumps to
> the error_unlink label and returns ret which is uninitialised.
>
> Fix this by setting err before jumping to error_unlink.
>
> Fixes: c7e4fc362443 ("wifi: mt76: mt7996: Update mt7996_mcu_add_sta to MLO support")
> Fixes: dd82a9e02c05 ("wifi: mt76: mt7996: Rely on mt7996_sta_link in sta_add/sta_remove callbacks")
> Signed-off-by: Qasim Ijaz <qasdev00@gmail.com>
> ---
>  drivers/net/wireless/mediatek/mt76/mt7996/main.c | 12 +++++++++---
>  1 file changed, 9 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/net/wireless/mediatek/mt76/mt7996/main.c b/drivers/net/wireless/mediatek/mt76/mt7996/main.c
> index 91c64e3a0860..78f7f1fc867e 100644
> --- a/drivers/net/wireless/mediatek/mt76/mt7996/main.c
> +++ b/drivers/net/wireless/mediatek/mt76/mt7996/main.c
> @@ -998,16 +998,22 @@ mt7996_mac_sta_add_links(struct mt7996_dev *dev, struct ieee80211_vif *vif,
>                         continue;
>
>                 link_conf = link_conf_dereference_protected(vif, link_id);
> -               if (!link_conf)
> +               if (!link_conf) {
> +                       err = -EINVAL;
>                         goto error_unlink;
> +               }
>
>                 link = mt7996_vif_link(dev, vif, link_id);
> -               if (!link)
> +               if (!link) {
> +                       err = -EINVAL;
>                         goto error_unlink;
> +               }
>
>                 link_sta = link_sta_dereference_protected(sta, link_id);
> -               if (!link_sta)
> +               if (!link_sta) {
> +                       err = -EINVAL

You are missing a semicolon at the end of the line.

To also do some bike shedding, you could initialize err (with 0 or
-EINVAL), and then change the err return to return err ? : -EINVAL;.
But your way has an explicit error code assigned to each failure, even
if it is always the same. So I won't claim my suggestion is better.

Best regards,
Jonas

Re: [PATCH] wifi: mt76: mt7996: prevent uninit return in mt7996_mac_sta_add_links

[Qasim Ijaz]

On Sat, Mar 22, 2025 at 12:51:57PM +0100, Jonas Gorski wrote:
> Hi,
> 
> On Thu, Mar 20, 2025 at 9:19 PM Qasim Ijaz <qasdev00@gmail.com> wrote:
> >
> > If link_conf_dereference_protected() or mt7996_vif_link()
> > or link_sta_dereference_protected() fail the code jumps to
> > the error_unlink label and returns ret which is uninitialised.
> >
> > Fix this by setting err before jumping to error_unlink.
> >
> > Fixes: c7e4fc362443 ("wifi: mt76: mt7996: Update mt7996_mcu_add_sta to MLO support")
> > Fixes: dd82a9e02c05 ("wifi: mt76: mt7996: Rely on mt7996_sta_link in sta_add/sta_remove callbacks")
> > Signed-off-by: Qasim Ijaz <qasdev00@gmail.com>
> > ---
> >  drivers/net/wireless/mediatek/mt76/mt7996/main.c | 12 +++++++++---
> >  1 file changed, 9 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/net/wireless/mediatek/mt76/mt7996/main.c b/drivers/net/wireless/mediatek/mt76/mt7996/main.c
> > index 91c64e3a0860..78f7f1fc867e 100644
> > --- a/drivers/net/wireless/mediatek/mt76/mt7996/main.c
> > +++ b/drivers/net/wireless/mediatek/mt76/mt7996/main.c
> > @@ -998,16 +998,22 @@ mt7996_mac_sta_add_links(struct mt7996_dev *dev, struct ieee80211_vif *vif,
> >                         continue;
> >
> >                 link_conf = link_conf_dereference_protected(vif, link_id);
> > -               if (!link_conf)
> > +               if (!link_conf) {
> > +                       err = -EINVAL;
> >                         goto error_unlink;
> > +               }
> >
> >                 link = mt7996_vif_link(dev, vif, link_id);
> > -               if (!link)
> > +               if (!link) {
> > +                       err = -EINVAL;
> >                         goto error_unlink;
> > +               }
> >
> >                 link_sta = link_sta_dereference_protected(sta, link_id);
> > -               if (!link_sta)
> > +               if (!link_sta) {
> > +                       err = -EINVAL
> 
> You are missing a semicolon at the end of the line.
> 

Good spot! not sure how that happened but I will resend a v2 patch.

> To also do some bike shedding, you could initialize err (with 0 or
> -EINVAL), and then change the err return to return err ? : -EINVAL;.
> But your way has an explicit error code assigned to each failure, even
> if it is always the same. So I won't claim my suggestion is better.
> 

Thanks for the suggestion, I think this could work however I think my 
current approach is more a bit more readable, so I will leave it as is.

Thanks,
Qasim

> Best regards,
> Jonas