[PATCH v2] ASoC: SOF: Intel: hda-dai: fix possible stream_tag leak

[Peter Ujfalusi <peter.ujfalusi@linux.intel.com>]

From: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>

The HDaudio stream allocation is done first, and in a second step the
LOSIDV parameter is programmed for the multi-link used by a codec.

This leads to a possible stream_tag leak, e.g. if a DisplayAudio link
is not used. This would happen when a non-Intel graphics card is used
and userspace unconditionally uses the Intel Display Audio PCMs without
checking if they are connected to a receiver with jack controls.

We should first check that there is a valid multi-link entry to
configure before allocating a stream_tag. This change aligns the
dma_assign and dma_cleanup phases.

Complements: b0cd60f3e9f5 ("ALSA/ASoC: hda: clarify bus_get_link() and bus_link_get() helpers")
Link: https://github.com/thesofproject/linux/issues/4151
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Reviewed-by: Rander Wang <rander.wang@intel.com>
Reviewed-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>
---
Hi Mark,

I have added a Complements tag for now to force it follow the rename patch.
I need to check how far this needs to go back and I will send a backported
version later on.

b0cd60f3e9f5 is in 6.2-rc

Thanks,
Peter

 sound/soc/sof/intel/hda-dai.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/sound/soc/sof/intel/hda-dai.c b/sound/soc/sof/intel/hda-dai.c
index 193b3e74820a..8d9c38d562d3 100644
--- a/sound/soc/sof/intel/hda-dai.c
+++ b/sound/soc/sof/intel/hda-dai.c
@@ -216,6 +216,10 @@ static int hda_link_dma_hw_params(struct snd_pcm_substream *substream,
 	sdev = snd_soc_component_get_drvdata(cpu_dai->component);
 	bus = sof_to_bus(sdev);
 
+	hlink = snd_hdac_ext_bus_get_hlink_by_name(bus, codec_dai->component->name);
+	if (!hlink)
+		return -EINVAL;
+
 	hext_stream = snd_soc_dai_get_dma_data(cpu_dai, substream);
 	if (!hext_stream) {
 		hext_stream = hda_link_stream_assign(bus, substream);
@@ -225,10 +229,6 @@ static int hda_link_dma_hw_params(struct snd_pcm_substream *substream,
 		snd_soc_dai_set_dma_data(cpu_dai, substream, (void *)hext_stream);
 	}
 
-	hlink = snd_hdac_ext_bus_get_hlink_by_name(bus, codec_dai->component->name);
-	if (!hlink)
-		return -EINVAL;
-
 	/* set the hdac_stream in the codec dai */
 	snd_soc_dai_set_stream(codec_dai, hdac_stream(hext_stream), substream->stream);
 
-- 
2.39.2