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authorXiyu Yang <xiyuyang19@fudan.edu.cn>2020-04-23 12:54:19 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2020-04-29 16:31:29 +0200
commit33bb5a4f25a2c7543141d10ac166599062c2d9d1 (patch)
treed8f7870c3c4a7e8227e22260e5d08ec8c07003fe
parentee5a44badde58a33f417960cfae405be1e6a568d (diff)
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ALSA: usb-audio: Fix usb audio refcnt leak when getting spdif
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 <xiyuyang19@fudan.edu.cn> Signed-off-by: Xin Tan <tanxin.ctf@gmail.com> Cc: <stable@vger.kernel.org> Link: https://lore.kernel.org/r/1587617711-13200-1-git-send-email-xiyuyang19@fudan.edu.cn Signed-off-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--sound/usb/mixer_quirks.c12
1 files changed, 8 insertions, 4 deletions
diff --git a/sound/usb/mixer_quirks.c b/sound/usb/mixer_quirks.c
index 10c6971cf477..983e8a3ebfcf 100644
--- a/sound/usb/mixer_quirks.c
+++ b/sound/usb/mixer_quirks.c
@@ -1519,11 +1519,15 @@ static int snd_microii_spdif_default_get(struct snd_kcontrol *kcontrol,
/* 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,