[PATCH] wifi: mt76: mt7925: guard link STA in decap offload

[Guangshuo Li]

mt7925_sta_set_decap_offload() iterates over the vif valid_links mask
when updating decap offload state for an MLO station. The station may not
have a link STA for every valid link of the vif, so mt792x_sta_to_link()
can return NULL for a link that belongs to the vif but not to the station.

The function currently dereferences mlink before checking whether the
link WCID is ready. If mlink is NULL, setting or clearing
MT_WCID_FLAG_HDR_TRANS dereferences a NULL pointer.

Skip links without a station link before touching mlink->wcid.

Fixes: b859ad65309a ("wifi: mt76: mt7925: add link handling in mt7925_sta_set_decap_offload")
Signed-off-by: Guangshuo Li <lgs201920130244 at gmail.com>
---
 drivers/net/wireless/mediatek/mt76/mt7925/main.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7925/main.c b/drivers/net/wireless/mediatek/mt76/mt7925/main.c
index a9059866b701..2b6cc8e253c0 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7925/main.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7925/main.c
@@ -1713,6 +1713,9 @@ static void mt7925_sta_set_decap_offload(struct ieee80211_hw *hw,
 		mconf = mt792x_vif_to_link(mvif, i);
 		mlink = mt792x_sta_to_link(msta, i);
 
+		if (!mlink)
+			continue;
+
 		if (enabled)
 			set_bit(MT_WCID_FLAG_HDR_TRANS, &mlink->wcid.flags);
 		else
-- 
2.43.0