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From:   Xiaomeng Tong <xiam0nd.tong@gmail.com>
To:     jbrunet@baylibre.com, lgirdwood@gmail.com, broonie@kernel.org,
        perex@perex.cz, tiwai@suse.com, narmstrong@baylibre.com,
        khilman@baylibre.com
Cc:     martin.blumenstingl@googlemail.com, alsa-devel@alsa-project.org,
        linux-arm-kernel@lists.infradead.org,
        linux-amlogic@lists.infradead.org, linux-kernel@vger.kernel.org,
        Xiaomeng Tong <xiam0nd.tong@gmail.com>, stable@vger.kernel.org
Subject: [PATCH] soc: meson: fix a missing check on list iterator
Date:   Sun, 27 Mar 2022 16:18:50 +0800
Message-Id: <20220327081850.13456-1-xiam0nd.tong@gmail.com>
Precedence: bulk

The bug is here:
	*dai_name = dai->driver->name;

For for_each_component_dais(), just like list_for_each_entry,
the list iterator 'runtime' will point to a bogus position
containing HEAD if the list is empty or no element is found.
This case must be checked before any use of the iterator,
otherwise it will lead to a invalid memory access.

To fix the bug, just move the assignment into loop and return
0 when element is found, otherwise return -EINVAL;

Cc: stable@vger.kernel.org
Fixes: 6ae9ca9ce986b ("ASoC: meson: aiu: add i2s and spdif support")
Signed-off-by: Xiaomeng Tong <xiam0nd.tong@gmail.com>
---
 sound/soc/meson/aiu.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/sound/soc/meson/aiu.c b/sound/soc/meson/aiu.c
index d299a70db7e5..b52915c6f53b 100644
--- a/sound/soc/meson/aiu.c
+++ b/sound/soc/meson/aiu.c
@@ -61,14 +61,14 @@ int aiu_of_xlate_dai_name(struct snd_soc_component *component,
 		return -EINVAL;
 
 	for_each_component_dais(component, dai) {
-		if (id == 0)
-			break;
+		if (id == 0) {
+			*dai_name = dai->driver->name;
+			return 0;
+		}
 		id--;
 	}
 
-	*dai_name = dai->driver->name;
-
-	return 0;
+	return -EINVAL;
 }
 
 static int aiu_cpu_of_xlate_dai_name(struct snd_soc_component *component,
-- 
2.17.1