When the driver fails in snd_card_register() at probe time, it will free
the 'bcd2k->midi_out_urb' before killing it, which may cause a UAF bug.
The following log can reveal it:
[ 50.727020] BUG: KASAN: use-after-free in bcd2000_input_complete+0x1f1/0x2e0 [snd_bcd2000]
[ 50.727623] Read of size 8 at addr ffff88810fab0e88 by task swapper/4/0
[ 50.729530] Call Trace:
[ 50.732899] bcd2000_input_complete+0x1f1/0x2e0 [snd_bcd2000]
Fix this by adding usb_kill_urb() before usb_free_urb().
Fixes: b47a22290d58 ("ALSA: MIDI driver for Behringer BCD2000 USB device")
Signed-off-by: Zheyu Ma <zheyuma97@xxxxxxxxx>
---
sound/usb/bcd2000/bcd2000.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/sound/usb/bcd2000/bcd2000.c b/sound/usb/bcd2000/bcd2000.c
index cd4a0bc6d278..7aec0a95c609 100644
--- a/sound/usb/bcd2000/bcd2000.c
+++ b/sound/usb/bcd2000/bcd2000.c
@@ -348,7 +348,8 @@ static int bcd2000_init_midi(struct bcd2000 *bcd2k)
static void bcd2000_free_usb_related_resources(struct bcd2000 *bcd2k,
struct usb_interface *interface)
{
- /* usb_kill_urb not necessary, urb is aborted automatically */
+ usb_kill_urb(bcd2k->midi_out_urb);
+ usb_kill_urb(bcd2k->midi_in_urb);
usb_free_urb(bcd2k->midi_out_urb);
usb_free_urb(bcd2k->midi_in_urb);
--
2.25.1
