Commit 3dcaa192 authored Jul 10, 2023 by Pauli Virtanen Committed by Luiz Augusto von Dentz Jul 20, 2023

Bluetooth: SCO: fix sco_conn related locking and validity issues



Operations that check/update sk_state and access conn should hold
lock_sock, otherwise they can race.

The order of taking locks is hci_dev_lock > lock_sock > sco_conn_lock,
which is how it is in connect/disconnect_cfm -> sco_conn_del ->
sco_chan_del.

Fix locking in sco_connect to take lock_sock around updating sk_state
and conn.

sco_conn_del must not occur during sco_connect, as it frees the
sco_conn. Hold hdev->lock longer to prevent that.

sco_conn_add shall return sco_conn with valid hcon. Make it so also when
reusing an old SCO connection waiting for disconnect timeout (see
__sco_sock_close where conn->hcon is set to NULL).

This should not reintroduce the issue fixed in the earlier
commit 9a8ec9e8 ("Bluetooth: SCO: Fix possible circular locking
dependency on sco_connect_cfm"), the relevant fix of releasing lock_sock
in sco_sock_connect before acquiring hdev->lock is retained.

These changes mirror similar fixes earlier in ISO sockets.

Fixes: 9a8ec9e8 ("Bluetooth: SCO: Fix possible circular locking dependency on sco_connect_cfm")
Signed-off-by: Pauli Virtanen <pav@iki.fi>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

parent b4066eb0

net/bluetooth/sco.c

+12 −11

Original line number	Diff line number	Diff line
		@@ -126,8 +126,11 @@ static struct sco_conn sco_conn_add(struct hci_conn hcon)
		struct hci_dev *hdev = hcon->hdev;
		struct sco_conn *conn = hcon->sco_data;

		if (conn)
		if (conn) {
		if (!conn->hcon)
		conn->hcon = hcon;
		return conn;
		}

		conn = kzalloc(sizeof(struct sco_conn), GFP_KERNEL);
		if (!conn)
		@@ -268,21 +271,21 @@ static int sco_connect(struct sock *sk)
		goto unlock;
		}

		hci_dev_unlock(hdev);
		hci_dev_put(hdev);

		conn = sco_conn_add(hcon);
		if (!conn) {
		hci_conn_drop(hcon);
		return -ENOMEM;
		err = -ENOMEM;
		goto unlock;
		}

		err = sco_chan_add(conn, sk, NULL);
		if (err)
		return err;

		lock_sock(sk);

		err = sco_chan_add(conn, sk, NULL);
		if (err) {
		release_sock(sk);
		goto unlock;
		}

		/* Update source addr of the socket */
		bacpy(&sco_pi(sk)->src, &hcon->src);

		@@ -296,8 +299,6 @@ static int sco_connect(struct sock *sk)

		release_sock(sk);

		return err;

		unlock:
		hci_dev_unlock(hdev);
		hci_dev_put(hdev);