Boiled.
However, keep in mind that the modern version of "boiled" is not the same as the historical.
Also, if you use the boiled on cotton canvas, it tends to make it stiff and prone to tearing (or cracking when folded in cold weather). Cotton is not very tough compared to linen or hemp.
Another option that could be used is "barn paint". Essentially a mixture of boiled linseed oil, colorants and dryers. Easier than making it yourself.