[RFC V4 PATCH 07/19] ALSA: mixer_audient: Add integer range checks

[Christian Ruppert <arc@gmx.li>]

Add range checks to integer parameters to improve error management:
- Reject out-of-range write attempts with -EINVAL
- Prune out-of-range values returned by the device to the range limits

Signed-off-by: Christian Ruppert <arc@gmx.li>
Signed-off-by: Will Porter <mrwillporter@gmail.com>
---
 sound/usb/mixer_audient.c | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/sound/usb/mixer_audient.c b/sound/usb/mixer_audient.c
index 4b20db9a82e2..433bb5479d8e 100644
--- a/sound/usb/mixer_audient.c
+++ b/sound/usb/mixer_audient.c
@@ -44,10 +44,10 @@ static const struct snd_audient_ctrl_type {
 	unsigned long flags;
 	size_t len;		/* datatype size, can be 1, 2 or 4 bytes */
 	union {
-		int integer;
+		long integer;
 	} min;		/* for booleans holds physical int value for false */
 	union {
-		int integer;
+		long integer;
 	} max;		/* for booleans holds physical int value for true */
 	const unsigned int *tlv;
 	u8 unit;
@@ -425,6 +425,12 @@ static int snd_ctl_audient_integer_get(struct snd_kcontrol *kctl,
 		if (ret < 0)
 			return ret;
 
+		if (val < ctype->min.integer)
+			val = ctype->min.integer;
+
+		if (val > ctype->max.integer)
+			val = ctype->max.integer;
+
 		ctl_val->value.integer.value[i] = val;
 	}
 
@@ -448,6 +454,13 @@ static int snd_ctl_audient_integer_set(struct snd_kcontrol *kctl,
 	int changed = 0;
 	int i;
 
+	for (i = 0; i < hwchan; i++) {
+		long val = ctl_val->value.integer.value[i];
+
+		if ((val < ctype->min.integer) || (val > ctype->max.integer))
+			return -EINVAL;
+	}
+
 	CLASS(snd_usb_lock, pm)(mixer->chip);
 	if (pm.err < 0)
 		return pm.err;
-- 
2.56.1