[PATCH 4/8] can: kvaser_usb: kvaser_usb_disconnect(): fix NULL pointer dereference

Vincent Mailhol
2022-12-03T13:33:30Z

kvaser_usb sets the usb_interface to NULL before waiting for the
completion of outstanding urbs. This can result 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 kvaser_usb_disconnect() at [3].

[1] commit 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: 080f40a6fa28 ("can: kvaser_usb: Add support for Kvaser CAN/USB devices")
Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
---
@stable team: the function was moved from kvaser_usb.c to
kvaser_usb_core.c in:

7259124eac7d1 ("can: kvaser_usb: Split driver into kvaser_usb_core.c and kvaser_usb_leaf.c")
---
drivers/net/can/usb/kvaser_usb/kvaser_usb_core.c | 2 --
1 file changed, 2 deletions(-)

diff --git a/drivers/net/can/usb/kvaser_usb/kvaser_usb_core.c b/drivers/net/can/usb/kvaser_usb/kvaser_usb_core.c
index 3a2bfaad1406..dad916b3288e 100644
--- a/drivers/net/can/usb/kvaser_usb/kvaser_usb_core.c
+++ b/drivers/net/can/usb/kvaser_usb/kvaser_usb_core.c
@@ -981,8 +981,6 @@ static void kvaser_usb_disconnect(struct usb_interface *intf)
{
struct kvaser_usb *dev = usb_get_intfdata(intf);

- usb_set_intfdata(intf, NULL);
-
if (!dev)
return;

--
2.37.4