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Bluetooth: SCO: fix sco_conn related locking and validity issues

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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 9a8ec9e8ebb5 ("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: 9a8ec9e8ebb5 ("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>
This commit is contained in:
Pauli Virtanen 2023-07-10 19:48:19 +03:00 committed by Luiz Augusto von Dentz
parent b4066eb04b
commit 3dcaa192ac
1 changed files with 12 additions and 11 deletions
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23
net/bluetooth/sco.c
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@ -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);