ALSA: pcm: Check PCM state at xfern compat ioctl

[ Upstream commit f13876e2c33a657a71bcbb10f767c0951b165020 ]

Since snd_pcm_ioctl_xfern_compat() has no PCM state check, it may go
further and hit the sanity check pcm_sanity_check() when the ioctl is
called right after open.  It may eventually spew a kernel warning, as
triggered by syzbot, depending on kconfig.

The lack of PCM state check there was just an oversight.  Although
it's no real crash, the spurious kernel warning is annoying, so let's
add the proper check.

Reported-by: syzbot+1dac3a4f6bc9c1c675d4@syzkaller.appspotmail.com
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>

diff --git a/sound/core/pcm_compat.c b/sound/core/pcm_compat.c
index 1f64ab0c2a95a291638406e62daa15ad6a172db3..7ae080bae15c1359a33d4067d9bdfa4ad3bbd1a9 100644 (file)
--- a/sound/core/pcm_compat.c
+++ b/sound/core/pcm_compat.c
@@ -426,6 +426,8 @@ static int snd_pcm_ioctl_xfern_compat(struct snd_pcm_substream *substream,
                return -ENOTTY;
        if (substream->stream != dir)
                return -EINVAL;
+       if (substream->runtime->status->state == SNDRV_PCM_STATE_OPEN)
+               return -EBADFD;
 
        if ((ch = substream->runtime->channels) > 128)
                return -EINVAL;