The driver stores a reference to the `usb_device` structure (`udev`)
in its private data (`data->udev`), which can persist beyond the
immediate context of the `bfusb_probe()` function.
Without proper reference count management, this can lead to two issues:
1. A `use-after-free` scenario if `udev` is accessed after its main
reference count drops to zero (e.g., if the device is disconnected
and the `data` structure is still active).
2. A `memory leak` if `udev`'s reference count is not properly
decremented during driver disconnect, preventing the `usb_device`
object from being freed.
To correctly manage the `udev` lifetime, explicitly increment its
reference count with `usb_get_dev(udev)` when storing it in the
driver's private data. Correspondingly, decrement the reference count
with `usb_put_dev(data->udev)` in the `bfusb_disconnect()` callback.
This ensures `udev` remains valid while referenced by the driver's
private data and is properly released when no longer needed.
Signed-off-by: Salah Triki <salah.triki@xxxxxxxxx>
Fixes: 9c724357f432d ("[Bluetooth] Code cleanup of the drivers source code")
Cc: stable@xxxxxxxxxxxxxxx
Cc: Marcel Holtmann <marcel@xxxxxxxxxxxx>
Cc: Luiz Augusto von Dentz <luiz.dentz@xxxxxxxxx>
Cc: linux-bluetooth@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
---
Changes in v3:
- Add tag Cc
Changes in v2:
- Add tags Fixes and Cc
drivers/bluetooth/bfusb.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/bluetooth/bfusb.c b/drivers/bluetooth/bfusb.c
index 8df310983bf6..f966bd8361b0 100644
--- a/drivers/bluetooth/bfusb.c
+++ b/drivers/bluetooth/bfusb.c
@@ -622,7 +622,7 @@ static int bfusb_probe(struct usb_interface *intf, const struct usb_device_id *i
if (!data)
return -ENOMEM;
- data->udev = udev;
+ data->udev = usb_get_dev(udev);
data->bulk_in_ep = bulk_in_ep->desc.bEndpointAddress;
data->bulk_out_ep = bulk_out_ep->desc.bEndpointAddress;
data->bulk_pkt_size = le16_to_cpu(bulk_out_ep->desc.wMaxPacketSize);
@@ -701,6 +701,8 @@ static void bfusb_disconnect(struct usb_interface *intf)
usb_set_intfdata(intf, NULL);
+ usb_put_dev(data->udev);
+
bfusb_close(hdev);
hci_unregister_dev(hdev);
--
2.43.0
