From: Xiyu Yang <xiyuyan...@fudan.edu.cn>
commit 59e1947ca09ebd1cae147c08c7c41f3141233c84 upstream.
snd_microii_spdif_default_get() invokes snd_usb_lock_shutdown(), which
increases the refcount of the snd_usb_audio object "chip".
When snd_microii_spdif_default_get() returns, local variable "chip"
becomes invalid, so the refcount should be decreased to keep refcount
balanced.
The reference counting issue happens in several exception handling paths
of snd_microii_spdif_default_get(). When those error scenarios occur
such as usb_ifnum_to_if() returns NULL, the function forgets to decrease
the refcnt increased by snd_usb_lock_shutdown(), causing a refcnt leak.
Fix this issue by jumping to "end" label when those error scenarios
occur.
Fixes: 447d6275f0c2 ("ALSA: usb-audio: Add sanity checks for endpoint accesses")
Signed-off-by: Xiyu Yang <xiyuyan...@fudan.edu.cn>
Signed-off-by: Xin Tan <tanxin....@gmail.com>
Cc: <sta...@vger.kernel.org>
Link:
https://lore.kernel.org/r/1587617711-13200-1-git-send-email-xiyuyan...@fudan.edu.cn
Signed-off-by: Takashi Iwai <ti...@suse.de>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
sound/usb/mixer_quirks.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
--- a/sound/usb/mixer_quirks.c
+++ b/sound/usb/mixer_quirks.c
@@ -1519,11 +1519,15 @@ static int snd_microii_spdif_default_get
/* use known values for that card: interface#1 altsetting#1 */
iface = usb_ifnum_to_if(chip->dev, 1);
- if (!iface || iface->num_altsetting < 2)
- return -EINVAL;
+ if (!iface || iface->num_altsetting < 2) {
+ err = -EINVAL;
+ goto end;
+ }
alts = &iface->altsetting[1];
- if (get_iface_desc(alts)->bNumEndpoints < 1)
- return -EINVAL;
+ if (get_iface_desc(alts)->bNumEndpoints < 1) {
+ err = -EINVAL;
+ goto end;
+ }
ep = get_endpoint(alts, 0)->bEndpointAddress;
err = snd_usb_ctl_msg(chip->dev,
