| Message ID | 20220715010515.2087925-1-zheyuma97@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | ALSA: bcd2000: Fix a UAF bug on the error path of probing | expand |
On Fri, 15 Jul 2022 03:05:15 +0200, Zheyu Ma wrote: > > 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@gmail.com> Thanks, applied. Takashi
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);
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@gmail.com> --- sound/usb/bcd2000/bcd2000.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)