[PATCH AUTOSEL 5.7 294/388] ASoC: dapm: Move dai_link widgets to runtime to fix use after free

Sasha Levin
2020-06-18T01:16:46Z

From: Charles Keepax <ckeepax@opensource.cirrus.com>

[ Upstream commit f4aa5e214eeaf7f1c7f157526a5aa29784cb6a1f ]

The newly added CODEC to CODEC DAI link widget pointers in
snd_soc_dai_link are better placed in snd_soc_pcm_runtime.
snd_soc_dai_link is really intended for static configuration of
the DAI, and the runtime for dynamic data. The snd_soc_dai_link
structures are not destroyed if the card is unbound. The widgets
are cleared up on unbind, however if the card is rebound as the
snd_soc_dai_link structures are reused these pointers will be left at
their old values, causing access to freed memory.

Fixes: 595571cca4de ("ASoC: dapm: Fix regression introducing multiple copies of DAI widgets")
Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Link: https://lore.kernel.org/r/20200526161930.30759-1-ckeepax@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
include/sound/soc.h | 6 +++---
sound/soc/soc-dapm.c | 12 ++++++------
2 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/include/sound/soc.h b/include/sound/soc.h
index e0371e70242d..8e480efeda2a 100644
--- a/include/sound/soc.h
+++ b/include/sound/soc.h
@@ -790,9 +790,6 @@ struct snd_soc_dai_link {
const struct snd_soc_pcm_stream *params;
unsigned int num_params;

- struct snd_soc_dapm_widget *playback_widget;
- struct snd_soc_dapm_widget *capture_widget;
-
unsigned int dai_fmt; /* format to set on init */

enum snd_soc_dpcm_trigger trigger[2]; /* trigger type for DPCM */
@@ -1156,6 +1153,9 @@ struct snd_soc_pcm_runtime {
struct snd_soc_dai **cpu_dais;
unsigned int num_cpus;

+ struct snd_soc_dapm_widget *playback_widget;
+ struct snd_soc_dapm_widget *capture_widget;
+
struct delayed_work delayed_work;
void (*close_delayed_work_func)(struct snd_soc_pcm_runtime *rtd);
#ifdef CONFIG_DEBUG_FS
diff --git a/sound/soc/soc-dapm.c b/sound/soc/soc-dapm.c
index e2632841b321..c0aa64ff8e32 100644
--- a/sound/soc/soc-dapm.c
+++ b/sound/soc/soc-dapm.c
@@ -4340,16 +4340,16 @@ static void dapm_connect_dai_pair(struct snd_soc_card *card,
codec = codec_dai->playback_widget;

if (playback_cpu && codec) {
- if (dai_link->params && !dai_link->playback_widget) {
+ if (dai_link->params && !rtd->playback_widget) {
substream = streams[SNDRV_PCM_STREAM_PLAYBACK].substream;
dai = snd_soc_dapm_new_dai(card, substream, "playback");
if (IS_ERR(dai))
goto capture;
- dai_link->playback_widget = dai;
+ rtd->playback_widget = dai;
}

dapm_connect_dai_routes(&card->dapm, cpu_dai, playback_cpu,
- dai_link->playback_widget,
+ rtd->playback_widget,
codec_dai, codec);
}

@@ -4358,16 +4358,16 @@ static void dapm_connect_dai_pair(struct snd_soc_card *card,
codec = codec_dai->capture_widget;

if (codec && capture_cpu) {
- if (dai_link->params && !dai_link->capture_widget) {
+ if (dai_link->params && !rtd->capture_widget) {
substream = streams[SNDRV_PCM_STREAM_CAPTURE].substream;
dai = snd_soc_dapm_new_dai(card, substream, "capture");
if (IS_ERR(dai))
return;
- dai_link->capture_widget = dai;
+ rtd->capture_widget = dai;
}

dapm_connect_dai_routes(&card->dapm, codec_dai, codec,
- dai_link->capture_widget,
+ rtd->capture_widget,
cpu_dai, capture_cpu);
}
}
--
2.25.1