[PATCH v2 6/9] can: ucan: ucan_disconnect(): fix NULL pointer dereference

Vincent Mailhol
2022-12-10T09:05:27Z

ucan sets the driver's priv data to NULL before waiting for the
completion of outsdanding urbs. This can results in NULL pointer
dereference, c.f. [1] and [2].

Remove the call to usb_set_intfdata(intf, NULL). The core will take
care of setting it to NULL after ucan_disconnect() at [3].

[1] c/27ef17849779 ("usb: add usb_set_intfdata() documentation")
Link: https://git.kernel.org/gregkh/usb/c/27ef17849779

[2] thread about usb_set_intfdata() on linux-usb mailing.
Link: https://lore.kernel.org/linux-usb/Y4OD70GD4KnoRk0k@rowland.harvard.edu/

[3] function usb_unbind_interface() from drivers/usb/core/driver.c
Link: https://elixir.bootlin.com/linux/v6.0/source/drivers/usb/core/driver.c#L497

Fixes: 9f2d3eae88d2 ("can: ucan: add driver for Theobroma Systems UCAN devices")
Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
---
drivers/net/can/usb/ucan.c | 2 --
1 file changed, 2 deletions(-)

diff --git a/drivers/net/can/usb/ucan.c b/drivers/net/can/usb/ucan.c
index ffa38f533c35..429b3519ee7f 100644
--- a/drivers/net/can/usb/ucan.c
+++ b/drivers/net/can/usb/ucan.c
@@ -1579,8 +1579,6 @@ static void ucan_disconnect(struct usb_interface *intf)
{
struct ucan_priv *up = usb_get_intfdata(intf);

- usb_set_intfdata(intf, NULL);
-
if (up) {
unregister_candev(up->netdev);
free_candev(up->netdev);
--
2.37.4