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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Dan Carpenter <dan.carpenter@oracle.com>,
        Mark Brown <broonie@kernel.org>
Subject: [PATCH 5.15 075/110] ASoC: max9759: fix underflow in speaker_gain_control_put()
Date:   Mon,  7 Feb 2022 12:06:48 +0100
Message-Id: <20220207103804.925662667@linuxfoundation.org>
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From: Dan Carpenter <dan.carpenter@oracle.com>

commit 4c907bcd9dcd233da6707059d777ab389dcbd964 upstream.

Check for negative values of "priv->gain" to prevent an out of bounds
access.  The concern is that these might come from the user via:
  -> snd_ctl_elem_write_user()
    -> snd_ctl_elem_write()
      -> kctl->put()

Fixes: fa8d915172b8 ("ASoC: max9759: Add Amplifier Driver")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/20220119123101.GA9509@kili
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 sound/soc/codecs/max9759.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/sound/soc/codecs/max9759.c
+++ b/sound/soc/codecs/max9759.c
@@ -64,7 +64,8 @@ static int speaker_gain_control_put(stru
 	struct snd_soc_component *c = snd_soc_kcontrol_component(kcontrol);
 	struct max9759 *priv = snd_soc_component_get_drvdata(c);
 
-	if (ucontrol->value.integer.value[0] > 3)
+	if (ucontrol->value.integer.value[0] < 0 ||
+	    ucontrol->value.integer.value[0] > 3)
 		return -EINVAL;
 
 	priv->gain = ucontrol->value.integer.value[0];