[RFC V4 PATCH 04/19] ALSA: mixer_audient: Add length check to USB transfer

[Christian Ruppert <arc@gmx.li>]

Check USB control transfers not only for errors but also for expected
length and return -EIO in case of error.

Signed-off-by: Christian Ruppert <arc@gmx.li>
Signed-off-by: Will Porter <mrwillporter@gmail.com>
---
 sound/usb/mixer_audient.c | 22 ++++++++++++++++------
 1 file changed, 16 insertions(+), 6 deletions(-)

diff --git a/sound/usb/mixer_audient.c b/sound/usb/mixer_audient.c
index 63714d00592c..1f3744a7c10a 100644
--- a/sound/usb/mixer_audient.c
+++ b/sound/usb/mixer_audient.c
@@ -244,9 +244,14 @@ static inline int snd_audient_get_cur(struct usb_mixer_interface *mixer,
 	const u16 value = U8_U8(sel, cidx);
 	const u16 index = U8_U8(unit, mixer->hostif->desc.bInterfaceNumber);
 
-	return snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0),
-			       UAC2_CS_CUR, AUDIENT_REQTYPE_GET,
-			       value, index, buf, len);
+	const int ret = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0),
+					UAC2_CS_CUR, AUDIENT_REQTYPE_GET,
+					value, index, buf, len);
+
+	if ((ret >= 0) && (ret != len))
+		return -EIO;
+
+	return ret;
 }
 
 static inline int snd_audient_set_cur(struct usb_mixer_interface *mixer,
@@ -258,9 +263,14 @@ static inline int snd_audient_set_cur(struct usb_mixer_interface *mixer,
 	const u16 value = U8_U8(sel, cidx);
 	const u16 index = U8_U8(unit, mixer->hostif->desc.bInterfaceNumber);
 
-	return snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
-			       UAC2_CS_CUR, AUDIENT_REQTYPE_SET,
-			       value, index, buf, len);
+	const int ret = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+					UAC2_CS_CUR, AUDIENT_REQTYPE_SET,
+					value, index, buf, len);
+
+	if ((ret >= 0) && (ret != len))
+		return -EIO;
+
+	return ret;
 }
 
 
-- 
2.56.1