From 3420fdb8ae99f0a08d78d2b80f42a71971cf478d Mon Sep 17 00:00:00 2001
From: Gaosheng Cui <cuigaosheng1@huawei.com>
Date: Fri, 18 Nov 2022 11:00:56 +0800
Subject: [PATCH] ASoC: amd: acp: Fix possible UAF in acp_dma_open
Git-commit: 3420fdb8ae99f0a08d78d2b80f42a71971cf478d
Patch-mainline: v6.2-rc1
References: bsc#1219136

Smatch report warning as follows:

sound/soc/amd/acp/acp-platform.c:199 acp_dma_open() warn:
  '&stream->list' not removed from list

If snd_pcm_hw_constraint_integer() fails in acp_dma_open(),
stream will be freed, but stream->list will not be removed from
adata->stream_list, then list traversal may cause UAF.

Fix by adding the newly allocated stream to the list once it's fully
initialised.

Fixes: 7929985cfe36 ("ASoC: amd: acp: Initialize list to store acp_stream during pcm_open")
Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com>
Link: https://lore.kernel.org/r/20221118030056.3135960-1-cuigaosheng1@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 sound/soc/amd/acp/acp-platform.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/sound/soc/amd/acp/acp-platform.c b/sound/soc/amd/acp/acp-platform.c
index 85a81add4ef9..447612a7a762 100644
--- a/sound/soc/amd/acp/acp-platform.c
+++ b/sound/soc/amd/acp/acp-platform.c
@@ -184,10 +184,6 @@ static int acp_dma_open(struct snd_soc_component *component, struct snd_pcm_subs
 
 	stream->substream = substream;
 
-	spin_lock_irq(&adata->acp_lock);
-	list_add_tail(&stream->list, &adata->stream_list);
-	spin_unlock_irq(&adata->acp_lock);
-
 	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
 		runtime->hw = acp_pcm_hardware_playback;
 	else
@@ -203,6 +199,10 @@ static int acp_dma_open(struct snd_soc_component *component, struct snd_pcm_subs
 
 	writel(1, ACP_EXTERNAL_INTR_ENB(adata));
 
+	spin_lock_irq(&adata->acp_lock);
+	list_add_tail(&stream->list, &adata->stream_list);
+	spin_unlock_irq(&adata->acp_lock);
+
 	return ret;
 }
 
-- 
2.35.3