Is it permissible to eat from the fruits of farms seized by the state, or to accept them as a gift, or to buy them from the market?

It is forbidden to seize the property of others without right. This prohibition includes both the state and individuals. Thus, it is not permissible for the state to usurp people's lands, nor for individuals to assist in their usurpation. Therefore, it is not permissible for anyone to consume the fruits of usurped land, whether it be a gift or a purchase.