[PATCH v2] wifi: mt76: mt7996: prevent uninit return in mt7996_mac_sta_add_links

[PATCH v2] 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>
---
v2:
- Added missing semi-colon as pointed out by Jonas Gorski

 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..70823bbb165c 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 v2] wifi: mt76: mt7996: prevent uninit return in mt7996_mac_sta_add_links

[Markus Elfring]

…
> or link_sta_dereference_protected() fail the code jumps to
> the error_unlink label and returns ret which is uninitialised.
…

* Would you like to avoid typos in such a change description?

* Can any background information become more relevant for the usage of
  source code analysis tools?

* Can the summary phrase be improved also another bit?


…
> +++ 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;
> +		}
…

Can software development interests evolve in ways which might make the avoidance
of duplicate source code more feasible also for affected error/exception handling?

Regards,
Markus