lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20231215214955.12110-24-quic_wcheng@quicinc.com>
Date: Fri, 15 Dec 2023 13:49:37 -0800
From: Wesley Cheng <quic_wcheng@...cinc.com>
To: <srinivas.kandagatla@...aro.org>, <mathias.nyman@...el.com>,
        <perex@...ex.cz>, <conor+dt@...nel.org>, <corbet@....net>,
        <gregkh@...uxfoundation.org>, <lgirdwood@...il.com>,
        <andersson@...nel.org>, <krzysztof.kozlowski+dt@...aro.org>,
        <konrad.dybcio@...aro.org>, <Thinh.Nguyen@...opsys.com>,
        <broonie@...nel.org>, <bgoswami@...cinc.com>, <tiwai@...e.com>,
        <robh+dt@...nel.org>, <agross@...nel.org>
CC: <linux-kernel@...r.kernel.org>, <devicetree@...r.kernel.org>,
        <linux-sound@...r.kernel.org>, <linux-usb@...r.kernel.org>,
        <linux-arm-msm@...r.kernel.org>, <linux-doc@...r.kernel.org>,
        <alsa-devel@...a-project.org>, Wesley Cheng <quic_wcheng@...cinc.com>
Subject: [PATCH v10 23/41] ALSA: usb-audio: Prevent starting of audio stream if in use

With USB audio offloading, an audio session is started from the ASoC
platform sound card and PCM devices.  Likewise, the USB SND path is still
readily available for use, in case the non-offload path is desired.  In
order to prevent the two entities from attempting to use the USB bus,
introduce a flag that determines when either paths are in use.

If a PCM device is already in use, the check will return an error to
userspace notifying that the stream is currently busy.  This ensures that
only one path is using the USB substream.

Signed-off-by: Wesley Cheng <quic_wcheng@...cinc.com>
---
 sound/usb/card.h |  1 +
 sound/usb/pcm.c  | 19 +++++++++++++++++--
 2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/sound/usb/card.h b/sound/usb/card.h
index ed4a664e24e5..6d59995440c3 100644
--- a/sound/usb/card.h
+++ b/sound/usb/card.h
@@ -165,6 +165,7 @@ struct snd_usb_substream {
 	unsigned int pkt_offset_adj;	/* Bytes to drop from beginning of packets (for non-compliant devices) */
 	unsigned int stream_offset_adj;	/* Bytes to drop from beginning of stream (for non-compliant devices) */
 
+	unsigned int opened:1;		/* pcm device opened */
 	unsigned int running: 1;	/* running status */
 	unsigned int period_elapsed_pending;	/* delay period handling */
 
diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c
index 3adb09ce1702..c2cb52cd5d23 100644
--- a/sound/usb/pcm.c
+++ b/sound/usb/pcm.c
@@ -1241,8 +1241,15 @@ static int snd_usb_pcm_open(struct snd_pcm_substream *substream)
 	struct snd_usb_stream *as = snd_pcm_substream_chip(substream);
 	struct snd_pcm_runtime *runtime = substream->runtime;
 	struct snd_usb_substream *subs = &as->substream[direction];
+	struct snd_usb_audio *chip = subs->stream->chip;
 	int ret;
 
+	mutex_lock(&chip->mutex);
+	if (subs->opened) {
+		mutex_unlock(&chip->mutex);
+		return -EBUSY;
+	}
+
 	runtime->hw = snd_usb_hardware;
 	/* need an explicit sync to catch applptr update in low-latency mode */
 	if (direction == SNDRV_PCM_STREAM_PLAYBACK &&
@@ -1259,13 +1266,17 @@ static int snd_usb_pcm_open(struct snd_pcm_substream *substream)
 
 	ret = setup_hw_info(runtime, subs);
 	if (ret < 0)
-		return ret;
+		goto out;
 	ret = snd_usb_autoresume(subs->stream->chip);
 	if (ret < 0)
-		return ret;
+		goto out;
 	ret = snd_media_stream_init(subs, as->pcm, direction);
 	if (ret < 0)
 		snd_usb_autosuspend(subs->stream->chip);
+	subs->opened = 1;
+out:
+	mutex_unlock(&chip->mutex);
+
 	return ret;
 }
 
@@ -1274,6 +1285,7 @@ static int snd_usb_pcm_close(struct snd_pcm_substream *substream)
 	int direction = substream->stream;
 	struct snd_usb_stream *as = snd_pcm_substream_chip(substream);
 	struct snd_usb_substream *subs = &as->substream[direction];
+	struct snd_usb_audio *chip = subs->stream->chip;
 	int ret;
 
 	snd_media_stop_pipeline(subs);
@@ -1287,6 +1299,9 @@ static int snd_usb_pcm_close(struct snd_pcm_substream *substream)
 
 	subs->pcm_substream = NULL;
 	snd_usb_autosuspend(subs->stream->chip);
+	mutex_lock(&chip->mutex);
+	subs->opened = 0;
+	mutex_unlock(&chip->mutex);
 
 	return 0;
 }

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ