[alsa-devel] Applied "ASoC: topology: Prevent use-after-free in snd_soc_get_pcm_runtime()" to the asoc tree

[Mark Brown]

The patch

   ASoC: topology: Prevent use-after-free in snd_soc_get_pcm_runtime()

has been applied to the asoc tree at

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git for-5.6

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.  

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark

>From 72b46612d06b83851e2e4f7b538a0bbeb69c10de Mon Sep 17 00:00:00 2001
From: Dragos Tarcatu <dragos_tarcatu at mentor.com>
Date: Tue, 17 Dec 2019 18:05:18 -0600
Subject: [PATCH] ASoC: topology: Prevent use-after-free in
 snd_soc_get_pcm_runtime()

remove_link() is currently calling snd_soc_remove_pcm_runtime() after
it has already freed the memory for the link name. But this is later
read from snd_soc_get_pcm_runtime() causing a KASAN use-after-free
warning. Reorder the cleanups to fix this issue.

Reviewed-by: Ranjani Sridharan <ranjani.sridharan at linux.intel.com>
Signed-off-by: Dragos Tarcatu <dragos_tarcatu at mentor.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart at linux.intel.com>
Acked-by: Kuninori Morimoto <kuninori.morimoto.gx at renesas.com>
Link: https://lore.kernel.org/r/20191218000518.5830-4-pierre-louis.bossart@linux.intel.com
Signed-off-by: Mark Brown <broonie at kernel.org>
---
 sound/soc/soc-topology.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/sound/soc/soc-topology.c b/sound/soc/soc-topology.c
index f8bd406c6198..2b3c74a0b126 100644
--- a/sound/soc/soc-topology.c
+++ b/sound/soc/soc-topology.c
@@ -548,14 +548,14 @@ static void remove_link(struct snd_soc_component *comp,
 	if (dobj->ops && dobj->ops->link_unload)
 		dobj->ops->link_unload(comp, dobj);
 
-	kfree(link->name);
-	kfree(link->stream_name);
-	kfree(link->cpus->dai_name);
-
 	list_del(&dobj->list);
 
 	snd_soc_remove_pcm_runtime(comp->card,
 			snd_soc_get_pcm_runtime(comp->card, link));
+
+	kfree(link->name);
+	kfree(link->stream_name);
+	kfree(link->cpus->dai_name);
 	kfree(link);
 }
 
-- 
2.20.1