[PATCH] ALSA: usb-audio: fix sign unintended sign extension on left shifts

From: Colin King
Date: Thu Jun 27 2019 - 12:43:17 EST


From: Colin Ian King <colin.king@xxxxxxxxxxxxx>

There are a couple of left shifts of unsigned 8 bit values that
first get promoted to signed ints and hence get sign extended
on the shift if the top bit of the 8 bit values are set. Fix
this by casting the 8 bit values to unsigned ints to stop the
unintentional sign extension.

Addresses-Coverity: ("Unintended sign extension")
Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
---
sound/usb/mixer_quirks.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/sound/usb/mixer_quirks.c b/sound/usb/mixer_quirks.c
index 1f6011f36bb0..199fa157a411 100644
--- a/sound/usb/mixer_quirks.c
+++ b/sound/usb/mixer_quirks.c
@@ -741,7 +741,7 @@ static int snd_ni_control_init_val(struct usb_mixer_interface *mixer,
return err;
}

- kctl->private_value |= (value << 24);
+ kctl->private_value |= ((unsigned int)value << 24);
return 0;
}

@@ -902,7 +902,7 @@ static int snd_ftu_eff_switch_init(struct usb_mixer_interface *mixer,
if (err < 0)
return err;

- kctl->private_value |= value[0] << 24;
+ kctl->private_value |= (unsigned int)value[0] << 24;
return 0;
}

--
2.20.1