11.04.2024 18:19, kovalev@xxxxxxxxxxxx wrote:
From: Vasiliy Kovalev <kovalev@xxxxxxxxxxxx>
When returning from the hci_disconnect() function, the conn->state
continues to be set to BT_CONNECTED and hci_conn_drop() is executed,
which decrements the conn->refcnt.
Syzkaller C reproducer:
https://lore.kernel.org/all/f8bb62a7-5845-53ed-7fbe-c0557c2745f2@xxxxxxxxxx/#t
During debugging, the value conn->refcnt goes down to -1000 and less.
Syzkaller has generated a reproducer that results in multiple calls to
hci_encrypt_change_evt() of the same conn object.
--
hci_encrypt_change_evt(){
// conn->state == BT_CONNECTED
hci_disconnect(){
hci_abort_conn();
}
hci_conn_drop();
// conn->state == BT_CONNECTED
}
--
This behavior can cause the conn->refcnt to go far into negative values
and cause problems. To get around this, you need to change the conn->state,
namely to BT_DISCONN, as it was before. > Fixes: a13f316e90fd ("Bluetooth: hci_conn: Consolidate code for
aborting connections")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Vasiliy Kovalev <kovalev@xxxxxxxxxxxx>
---
net/bluetooth/hci_event.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index 64477e1bde7cec..e0477021183f9b 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -2989,6 +2989,7 @@ static void hci_cs_le_start_enc(struct hci_dev *hdev, u8 status)
hci_disconnect(conn, HCI_ERROR_AUTH_FAILURE);
hci_conn_drop(conn);
+ conn->state = BT_DISCONN;
unlock:
hci_dev_unlock(hdev);
@@ -3654,6 +3655,7 @@ static void hci_encrypt_change_evt(struct hci_dev *hdev, void *data,
hci_encrypt_cfm(conn, ev->status);
hci_disconnect(conn, HCI_ERROR_AUTH_FAILURE);
hci_conn_drop(conn);
+ conn->state = BT_DISCONN;
goto unlock;
}
@@ -5248,6 +5250,7 @@ static void hci_key_refresh_complete_evt(struct hci_dev *hdev, void *data,
if (ev->status && conn->state == BT_CONNECTED) {
hci_disconnect(conn, HCI_ERROR_AUTH_FAILURE);
hci_conn_drop(conn);
+ conn->state = BT_DISCONN;
goto unlock;
}
--
Regards,
Vasiliy Kovalev
