From: Guennadi Liakhovetski Date: Fri, 1 Feb 2019 17:05:13 +0000 (-0600) Subject: ASoC: topology: fix oops/use-after-free case with dai driver X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=52abe6cc1866a;p=openwrt%2Fstaging%2Fblogic.git ASoC: topology: fix oops/use-after-free case with dai driver rmmod/modprobe tests expose a kernel oops when accessing the dai driver pointer. This comes from the topology design which operates in multiple passes. Each object removal happens at a specific iteration, and the code checks for the iteration (order) number after the memory containing the order was freed. Fix this be clearing a reference to the dai driver and check its validity to avoid dereferences. Signed-off-by: Guennadi Liakhovetski Signed-off-by: Pierre-Louis Bossart Signed-off-by: Mark Brown --- diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c index ea16c2b199ce..50617db05c46 100644 --- a/sound/soc/soc-core.c +++ b/sound/soc/soc-core.c @@ -956,7 +956,7 @@ static void soc_remove_dai(struct snd_soc_dai *dai, int order) { int err; - if (!dai || !dai->probed || + if (!dai || !dai->probed || !dai->driver || dai->driver->remove_order != order) return; diff --git a/sound/soc/soc-topology.c b/sound/soc/soc-topology.c index 045ef136903d..fc79ec6927e3 100644 --- a/sound/soc/soc-topology.c +++ b/sound/soc/soc-topology.c @@ -502,6 +502,7 @@ static void remove_dai(struct snd_soc_component *comp, { struct snd_soc_dai_driver *dai_drv = container_of(dobj, struct snd_soc_dai_driver, dobj); + struct snd_soc_dai *dai; if (pass != SOC_TPLG_PASS_PCM_DAI) return; @@ -509,6 +510,10 @@ static void remove_dai(struct snd_soc_component *comp, if (dobj->ops && dobj->ops->dai_unload) dobj->ops->dai_unload(comp, dobj); + list_for_each_entry(dai, &comp->dai_list, list) + if (dai->driver == dai_drv) + dai->driver = NULL; + kfree(dai_drv->name); list_del(&dobj->list); kfree(dai_drv);