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Bluetooth: RFCOMM: free the skb when the DLC has no owner

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rfcomm_recv_data() hands the skb to d->data_ready() and returns 0
without freeing it, so the callback owns the skb from that point on.
The tty implementation frees it when the DLC has been detached from its
device:

  static void rfcomm_dev_data_ready(struct rfcomm_dlc *dlc,
                                    struct sk_buff *skb)
  {
          struct rfcomm_dev *dev = dlc->owner;

          if (!dev) {
                  kfree_skb(skb);
                  return;
          }

The socket implementation returns without freeing it, and the skb is
leaked.

A connected DLC can have no owner: rfcomm_sock_destruct() clears
d->owner, while the DLC itself stays on the session until it is closed.
Data frames that arrive in that window still find d->state ==
BT_CONNECTED in rfcomm_recv_data() and are handed to the callback, one
leaked skb each.

The leak does not stop on its own either.  The remote runs out of
credits only once RFCOMM_RX_THROTTLED is set, and for a socket the only
place that sets it is rfcomm_sk_data_ready() itself, below the return.
rfcomm_process_dlcs() keeps granting credits, so the remote keeps
sending and the leak keeps growing.

Free the skb, as the tty side does.

Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Reported-by: Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com>
Closes: https://lore.kernel.org/linux-bluetooth/CABXGCsPe5wykd8Aj-hm+SJ7SGQyb8yoGNnx3XDpPmBathj+EGg@mail.gmail.com/
Cc: stable@vger.kernel.org
Signed-off-by: Maxim Skokov <skokovmaksimevg@gmail.com>
Assisted-by: Claude:claude-opus-5
Reviewed-by: Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
This commit is contained in:
Maxim Skokov 2026-09-15 10:00:46 +03:00 • committed by Luiz Augusto von Dentz
commit 9d1afbf60e
1 changed files with 4 additions and 1 deletions
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