ALSA: usb-audio: Fix potential memory leaks

When the driver hits -ENOMEM at allocating a URB or a buffer, it
aborts and goes to the error path that releases the all previously
allocated resources.  However, when -ENOMEM hits at the middle of the
sync EP URB allocation loop, the partially allocated URBs might be
left without released, because ep->nurbs is still zero at that point.

Fix it by setting ep->nurbs at first, so that the error handler loops
over the full URB list.

Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20220930100151.19461-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/usb/endpoint.c b/sound/usb/endpoint.c
index 36f753a28341bba4a9db4f77acb908333da62acf..48a3843a08f11ff23617e8ac6a0e5291222e7982 100644 (file)
--- a/sound/usb/endpoint.c
+++ b/sound/usb/endpoint.c
@@ -1268,6 +1268,7 @@ static int sync_ep_set_params(struct snd_usb_endpoint *ep)
        if (!ep->syncbuf)
                return -ENOMEM;
 
+       ep->nurbs = SYNC_URBS;
        for (i = 0; i < SYNC_URBS; i++) {
                struct snd_urb_ctx *u = &ep->urb[i];
                u->index = i;
@@ -1287,8 +1288,6 @@ static int sync_ep_set_params(struct snd_usb_endpoint *ep)
                u->urb->complete = snd_complete_urb;
        }
 
-       ep->nurbs = SYNC_URBS;
-
        return 0;
 
 out_of_memory: