mac802154: fix use-after-free of sdata via queued RX frames

The RX softirq producer ieee802154_subif_frame() queues received beacon
and MAC-command frames onto local->rx_beacon_list / rx_mac_cmd_list and
schedules a process-context worker, storing a raw mac_pkt->sdata (and
skb->dev == sdata->dev) with neither a reference nor any locking:

 - the lists have no lock: the softirq producer list_add_tail()s while the
   mac_wq worker list_del()s, so sibling interfaces on the same phy corrupt
   the list;

 - the workers dereference the interface after it may have been freed.
   mac802154_rx_mac_cmd_worker() touches mac_pkt->sdata directly, and
   mac802154_rx_beacon_worker() -> mac802154_process_beacon() dereferences
   skb->dev (== sdata->dev). Removing an interface frees its sdata
   (netdev_priv) while a queued frame still points at it, so a later worker
   run is a use-after-free.

Reproduced under KASAN by flooding a victim interface with MAC command
frames and removing it (the beacon path is the same class via skb->dev):

  BUG: KASAN: slab-use-after-free in mac802154_rx_mac_cmd_worker+0x463/0x630 [mac802154]
  Read of size 4 at addr ffff888002f9ea18 by task kworker/u8:1/31
  Workqueue: phy0-mac-cmds mac802154_rx_mac_cmd_worker [mac802154]
  Call Trace:
   mac802154_rx_mac_cmd_worker+0x463/0x630 [mac802154]
   process_one_work+0x611/0xe80
   worker_thread+0x52e/0xdc0
   kthread+0x30c/0x630
   ret_from_fork+0x2fd/0x3e0

Fix both lists together:

 - add local->rx_lock and take it around every list access: the softirq
   producer (plain spin_lock, softirq context) and the workers and flush
   (spin_lock_bh, process context);

 - pin the interface for the lifetime of a queued frame with
   netdev_hold()/netdev_put(), so the worker can safely dereference sdata /
   skb->dev even while the interface is being removed;

 - dequeue under the lock at the head and loop-drain the whole list in the
   workers (they previously processed one frame per run and relied on a
   later enqueue to drain the rest);

 - drop not-yet-started frames of an interface before it is unregistered,
   from ieee802154_if_remove() (after the RCU grace period) and from the
   ieee802154_remove_interfaces() loop -- the latter is the whole-phy
   teardown path, which does not go through ieee802154_if_remove().

An in-flight worker that already dequeued a frame keeps its own netdev
reference; unregister_netdevice() then waits it out in netdev_run_todo(),
which runs at rtnl_unlock() (rtnl released) and after the interface has
been closed, so it does not pin rtnl. A worker blocked in an association
TX only delays that one interface's unregister (the usual "waiting for %s
to become free"), it does not hold rtnl. netdev_hold() is used for this
reason instead of a cancel_work_sync() under rtnl, which would block on
the worker's unbounded MLME TX wait via ieee802154_sync_queue().

The mac-command worker additionally skips processing for a stopped
interface (ieee802154_sdata_running()), avoiding a needless association
response during teardown.

Fixes: 57588c71177f ("mac802154: Handle passive scanning")
Cc: stable@vger.kernel.org
Signed-off-by: Ibrahim Hashimov <security@auditcode.ai>
Assisted-by: AuditCode-AI:2026.07
Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/20260725135154.99876-1-security@auditcode.ai
Signed-off-by: Stefan Schmidt <stefan@datenfreihafen.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/net/cfg802154.h b/include/net/cfg802154.h
index 76d2cd2e2b30..2e960441ea49 100644
--- a/include/net/cfg802154.h
+++ b/include/net/cfg802154.h
@@ -376,6 +376,7 @@ struct cfg802154_mac_pkt {
 	struct list_head node;
 	struct sk_buff *skb;
 	struct ieee802154_sub_if_data *sdata;
+	netdevice_tracker dev_tracker;
 	u8 page;
 	u8 channel;
 };