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From:   Alexey Khoroshilov <khoroshilov@ispras.ru>
To:     Liam Girdwood <lgirdwood@gmail.com>,
        Mark Brown <broonie@kernel.org>
Cc:     Alexey Khoroshilov <khoroshilov@ispras.ru>,
        Jaroslav Kysela <perex@perex.cz>,
        Takashi Iwai <tiwai@suse.com>, alsa-devel@alsa-project.org,
        linux-kernel@vger.kernel.org, ldv-project@linuxtesting.org
Subject: [PATCH] ASoC: max98090: Move check for invalid values before casting in max98090_put_enab_tlv()
Date:   Fri, 20 May 2022 01:31:26 +0300
Message-Id: <1652999486-29653-1-git-send-email-khoroshilov@ispras.ru>
In-Reply-To: <YoajesD+D1W3ZV7/@sirena.org.uk>
Precedence: bulk

Validation of signed input should be done before casting to unsigned int.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Suggested-by: Mark Brown <broonie@kernel.org>
Fixes: 2fbe467bcbfc ("ASoC: max98090: Reject invalid values in custom control put()")
---
 sound/soc/codecs/max98090.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/sound/soc/codecs/max98090.c b/sound/soc/codecs/max98090.c
index 62b41ca050a2..5513acd360b8 100644
--- a/sound/soc/codecs/max98090.c
+++ b/sound/soc/codecs/max98090.c
@@ -393,7 +393,8 @@ static int max98090_put_enab_tlv(struct snd_kcontrol *kcontrol,
 	struct soc_mixer_control *mc =
 		(struct soc_mixer_control *)kcontrol->private_value;
 	unsigned int mask = (1 << fls(mc->max)) - 1;
-	unsigned int sel = ucontrol->value.integer.value[0];
+	int sel_unchecked = ucontrol->value.integer.value[0];
+	unsigned int sel;
 	unsigned int val = snd_soc_component_read(component, mc->reg);
 	unsigned int *select;
 
@@ -413,8 +414,9 @@ static int max98090_put_enab_tlv(struct snd_kcontrol *kcontrol,
 
 	val = (val >> mc->shift) & mask;
 
-	if (sel < 0 || sel > mc->max)
+	if (sel_unchecked < 0 || sel_unchecked > mc->max)
 		return -EINVAL;
+	sel = sel_unchecked;
 
 	*select = sel;
 
-- 
2.7.4