[PATCH] wifi: mt76: fix unlocked wcid check in mt76_tx_status_skb_add()
Ryan Leung <[email protected]>
| Newsgroups | org.kernel.vger.linux-wireless,org.infradead.lists.linux-arm-kernel,org.infradead.lists.linux-mediatek,org.kernel.vger.linux-kernel |
|---|---|
| Message-ID | <[email protected]> |
mt76_tx_status_skb_add() checks rcu_access_pointer(dev->wcid[wcid->idx])
before taking dev->status_lock, then allocates a pktid afterwards. A
concurrent mt76_wcid_cleanup() can run between the check and the lock,
letting a stale wcid be re-added to dev->wcid_list after teardown.
Move the check inside the status_lock section, so that it is atomic
with the idr_alloc() and wcid_list update.
Fixes: fcfe1b5e162b ("mt76: fix tx status related use-after-free race on station removal")
Signed-off-by: Ryan Leung <[email protected]>
---
drivers/net/wireless/mediatek/mt76/tx.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/net/wireless/mediatek/mt76/tx.c b/drivers/net/wireless/mediatek/mt76/tx.c
index 3707ee19e4ae..fa635fe84ec2 100644
--- a/drivers/net/wireless/mediatek/mt76/tx.c
+++ b/drivers/net/wireless/mediatek/mt76/tx.c
@@ -129,7 +129,7 @@ mt76_tx_status_skb_add(struct mt76_dev *dev, struct mt76_wcid *wcid,
memset(cb, 0, sizeof(*cb));
- if (!wcid || !rcu_access_pointer(dev->wcid[wcid->idx]))
+ if (!wcid)
return MT_PACKET_ID_NO_ACK;
if (info->flags & IEEE80211_TX_CTL_NO_ACK)
@@ -147,6 +147,11 @@ mt76_tx_status_skb_add(struct mt76_dev *dev, struct mt76_wcid *wcid,
spin_lock_bh(&dev->status_lock);
+ if (!rcu_access_pointer(dev->wcid[wcid->idx])) {
+ pid = MT_PACKET_ID_NO_ACK;
+ goto out;
+ }
+
pid = idr_alloc(&wcid->pktid, skb, MT_PACKET_ID_FIRST,
MT_PACKET_ID_MASK, GFP_ATOMIC);
if (pid < 0) {
---
base-commit: ca800a9302764c445de0da0e84d2252400a770ee
change-id: 20260821-mt76-stale-wcid-race-4d92f898437b
Best regards,
--
Ryan Leung <[email protected]>