blob: a5f8af684526290bd8ec24922c053fa90784c387 [file] [log] [blame]
From 862fa160ae0771b1e562da9c8b52d8f0bc5c8344 Mon Sep 17 00:00:00 2001
From: Takashi Iwai <>
Date: Tue, 16 Jun 2020 14:09:21 +0200
Subject: [PATCH] ALSA: usb-audio: Fix potential use-after-free of streams
commit ff58bbc7b9704a5869204176f804eff57307fef0 upstream.
With the recent full-duplex support of implicit feedback streams, an
endpoint can be still running after closing the capture stream as long
as the playback stream with the sync-endpoint is running. In such a
state, the URBs are still be handled and they may call retire_data_urb
callback, which tries to transfer the data from the PCM buffer. Since
the PCM stream gets closed, this may lead to use-after-free.
This patch adds the proper clearance of the callback at stopping the
capture stream for addressing the possible UAF above.
Fixes: 10ce77e4817f ("ALSA: usb-audio: Add duplex sound support for USB devices using implicit feedback")
Signed-off-by: Takashi Iwai <>
Signed-off-by: Paul Gortmaker <>
diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c
index ccc1fba59df2..a07155faaac6 100644
--- a/sound/usb/pcm.c
+++ b/sound/usb/pcm.c
@@ -1739,6 +1739,7 @@ static int snd_usb_substream_playback_trigger(struct snd_pcm_substream *substrea
return 0;
stop_endpoints(subs, false);
+ subs->data_endpoint->retire_data_urb = NULL;
subs->running = 0;
return 0;