From 5f26a690e8efa54315e4922368daf54e0b8f5515 Mon Sep 17 00:00:00 2001 From: Zihan Xi Date: Sun, 2 Aug 2026 09:23:34 +0000 Subject: [PATCH] mac802154: fix netdev use-after-free in beacon worker mac802154_beacon_worker() reads local->beacon_req under RCU and derives the sub-interface from the request, but then drops the RCU read lock and continues to use both sdata and the embedded wpan_dev. mac802154_stop_beacons_locked() cancels only pending beacon work, clears local->beacon_req and frees the request. A beacon worker that is already running can therefore continue after interface teardown and dereference the freed netdev private area. The scan worker already pins the netdev before leaving RCU. Apply the same lifetime rule to the beacon worker: take a netdev reference while the request is still protected by RCU, and release it on all paths that continue after the reference is acquired. Fixes: 3accf4762734 ("mac802154: Handle basic beaconing") Cc: stable@vger.kernel.org Reported-by: Vega Signed-off-by: Zihan Xi Reviewed-by: Miquel Raynal Link: https://patch.msgid.link/e9a3909c7a6281967961773ca841e860b8ecf40e.1785596603.git.zihanx@nebusec.ai Signed-off-by: Jakub Kicinski --- net/mac802154/scan.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/net/mac802154/scan.c b/net/mac802154/scan.c index 65089826ff59..005338f89b75 100644 --- a/net/mac802154/scan.c +++ b/net/mac802154/scan.c @@ -415,6 +415,7 @@ void mac802154_beacon_worker(struct work_struct *work) container_of(work, struct ieee802154_local, beacon_work.work); struct cfg802154_beacon_request *beacon_req; struct ieee802154_sub_if_data *sdata; + netdevice_tracker dev_tracker; struct wpan_dev *wpan_dev; u8 interval; int ret; @@ -427,12 +428,14 @@ void mac802154_beacon_worker(struct work_struct *work) } sdata = IEEE802154_WPAN_DEV_TO_SUB_IF(beacon_req->wpan_dev); + netdev_hold(sdata->dev, &dev_tracker, GFP_ATOMIC); /* Wait an arbitrary amount of time in case we cannot use the device */ if (local->suspended || !ieee802154_sdata_running(sdata)) { rcu_read_unlock(); queue_delayed_work(local->mac_wq, &local->beacon_work, msecs_to_jiffies(1000)); + netdev_put(sdata->dev, &dev_tracker); return; } @@ -450,6 +453,7 @@ void mac802154_beacon_worker(struct work_struct *work) if (interval < IEEE802154_ACTIVE_SCAN_DURATION) queue_delayed_work(local->mac_wq, &local->beacon_work, local->beacon_interval); + netdev_put(sdata->dev, &dev_tracker); } int mac802154_stop_beacons_locked(struct ieee802154_local *local,