[PATCH 4.19 79/86] ASoC: max9759: fix underflow in speaker_gain_control_put()

Greg Kroah-Hartman
2022-02-07T11:25:07Z

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];