[PATCH 02/11] ALSA: usb-audio: Fix undefined behavior due to shift overflowing the constant

From: Borislav Petkov
Date: Tue Apr 05 2022 - 16:42:16 EST


From: Borislav Petkov <bp@xxxxxxx>

Fix:

sound/usb/midi.c: In function ‘snd_usbmidi_out_endpoint_create’:
sound/usb/midi.c:1389:2: error: case label does not reduce to an integer constant
case USB_ID(0xfc08, 0x0101): /* Unknown vendor Cable */
^~~~

See https://lore.kernel.org/r/YkwQ6%2BtIH8GQpuct@xxxxxxx for the gory
details as to why it triggers with older gccs only.

Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Cc: Jaroslav Kysela <perex@xxxxxxxx>
Cc: Takashi Iwai <tiwai@xxxxxxxx>
Cc: alsa-devel@xxxxxxxxxxxxxxxx
---
sound/usb/usbaudio.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/usb/usbaudio.h b/sound/usb/usbaudio.h
index 167834133b9b..2b3dd55e8ee0 100644
--- a/sound/usb/usbaudio.h
+++ b/sound/usb/usbaudio.h
@@ -8,7 +8,7 @@
*/

/* handling of USB vendor/product ID pairs as 32-bit numbers */
-#define USB_ID(vendor, product) (((vendor) << 16) | (product))
+#define USB_ID(vendor, product) ((((unsigned int)vendor) << 16) | (product))
#define USB_ID_VENDOR(id) ((id) >> 16)
#define USB_ID_PRODUCT(id) ((u16)(id))

--
2.35.1