You can make your own with equal parts of varnish, boiled linseed oil and mineral spirits.
It will be fine for your knife handle.
I like to heat it in a soup can set in boiling water. That makes it penetrate the wood deeper and dry faster. Apply a heavy coat let it set a few minutes then rub it into the wood. Wipe off any excess and let it dry at least 24 hours. Rub with extra fine steel wool or 300 grit or higher sand paper between coats. Repeat three to four times.