linux-kernel - [PATCH v3] ASoC: samsung: i2s: Null pointer dereference on samsung_i2s

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Date:   Fri, 11 Aug 2017 16:06:23 +0300
From:   Anton Vasilyev <vasilyev@...ras.ru>
To:     Sylwester Nawrocki <s.nawrocki@...sung.com>
Cc:     Anton Vasilyev <vasilyev@...ras.ru>,
        Krzysztof Kozlowski <krzk@...nel.org>,
        Sangbeom Kim <sbkim73@...sung.com>,
        Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>,
        Jaroslav Kysela <perex@...ex.cz>,
        Takashi Iwai <tiwai@...e.com>, alsa-devel@...a-project.org,
        linux-kernel@...r.kernel.org, ldv-project@...uxtesting.org
Subject: [PATCH v3] ASoC: samsung: i2s: Null pointer dereference on samsung_i2s_remove

If (quirks & QUIRK_SEC_DAI == 0) then samsung_i2s_probe() doesn't allocate
sec_dai and pri_dai->sec_dai remains Null, but samsung_i2s_remove()
performs pri_dai->sec_dai dereference in any case.

The patch adds sec_dai check on Null before derefence at
samsung_i2s_remove().

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Anton Vasilyev <vasilyev@...ras.ru>
---
v2: Drop initialization of sec_dai by NULL at samsung_i2s_remove
as Sylwester Nawrocki suggest.
---
v3: Fix typo in the comment
---
 sound/soc/samsung/i2s.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/sound/soc/samsung/i2s.c b/sound/soc/samsung/i2s.c
index af3ba4d..6f896e3 100644
--- a/sound/soc/samsung/i2s.c
+++ b/sound/soc/samsung/i2s.c
@@ -1376,13 +1376,9 @@ static int samsung_i2s_probe(struct platform_device *pdev)
 
 static int samsung_i2s_remove(struct platform_device *pdev)
 {
-	struct i2s_dai *pri_dai, *sec_dai;
+	struct i2s_dai *pri_dai;
 
 	pri_dai = dev_get_drvdata(&pdev->dev);
-	sec_dai = pri_dai->sec_dai;
-
-	pri_dai->sec_dai = NULL;
-	sec_dai->pri_dai = NULL;
 
 	pm_runtime_get_sync(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
-- 
2.7.4