From 3d4f23885e4b90347c9a1d779af6e79a99b5172a Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Mon, 9 Mar 2026 11:46:27 +0100 Subject: ALSA: usb-audio: Check endpoint numbers at parsing Scarlett2 mixer interfaces commit df1d8abf36ca3681c21a6809eaa9a1e01ef897a6 upstream. The Scarlett2 mixer quirk in USB-audio driver may hit a NULL dereference when a malformed USB descriptor is passed, since it assumes the presence of an endpoint in the parsed interface in scarlett2_find_fc_interface(), as reported by fuzzer. For avoiding the NULL dereference, just add the sanity check of bNumEndpoints and skip the invalid interface. Reported-by: syzbot+8f29539ef9a1c8334f42@syzkaller.appspotmail.com Closes: https://lore.kernel.org/69acbbe1.050a0220.310d8.0001.GAE@google.com Reported-by: syzbot+ae893a8901067fde2741@syzkaller.appspotmail.com Closes: https://lore.kernel.org/69acf72a.050a0220.310d8.0004.GAE@google.com Cc: Link: https://patch.msgid.link/20260309104632.141895-1-tiwai@suse.de Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman --- sound/usb/mixer_scarlett2.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'sound/usb/mixer_scarlett2.c') diff --git a/sound/usb/mixer_scarlett2.c b/sound/usb/mixer_scarlett2.c index 7b31504c5f24..4342d93ab771 100644 --- a/sound/usb/mixer_scarlett2.c +++ b/sound/usb/mixer_scarlett2.c @@ -8251,6 +8251,8 @@ static int scarlett2_find_fc_interface(struct usb_device *dev, if (desc->bInterfaceClass != 255) continue; + if (desc->bNumEndpoints < 1) + continue; epd = get_endpoint(intf->altsetting, 0); private->bInterfaceNumber = desc->bInterfaceNumber; -- cgit v1.2.3