USB: microtek: fix info-leak at probe

BugLink: https://bugs.launchpad.net/bugs/1848780

commit 177238c3 upstream.

Add missing bulk-in endpoint sanity check to prevent uninitialised stack
data from being reported to the system log and used as endpoint
addresses.

Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Cc: stable <stable@vger.kernel.org>
Reported-by: syzbot+5630ca7c3b2be5c9da5e@syzkaller.appspotmail.com
Signed-off-by: Johan Hovold <johan@kernel.org>
Acked-by: Oliver Neukum <oneukum@suse.com>
Link: https://lore.kernel.org/r/20191003070931.17009-1-johan@kernel.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Connor Kuehl <connor.kuehl@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

drivers/usb/image/microtek.c

@@ -724,6 +724,10 @@ static int mts_usb_probe(struct usb_interface *intf,
 
 	}
 
+	if (ep_in_current != &ep_in_set[2]) {
+		MTS_WARNING("couldn't find two input bulk endpoints. Bailing out.\n");
+		return -ENODEV;
+	}
 
 	if ( ep_out == -1 ) {
 		MTS_WARNING( "couldn't find an output bulk endpoint. Bailing out.\n" );