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ALSA: bcd2000: Fix a UAF bug on the error path of probing

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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: b47a22290d ("ALSA: MIDI driver for Behringer BCD2000 USB device")
Signed-off-by: Zheyu Ma <zheyuma97@gmail.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20220715010515.2087925-1-zheyuma97@gmail.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Zheyu Ma 2022-07-15 09:05:15 +08:00 committed by Takashi Iwai
parent 63f4b99f00
commit ffb2759df7
1 changed files with 2 additions and 1 deletions
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3
sound/usb/bcd2000/bcd2000.c
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@ -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);