[The Ruling on a Sale with a Condition of Rescission (Iqālah)]

Answer: The sale in question—if it is as was known formerly, where there is an intention to exploit the land and benefit from its produce—then the sale is invalid; it is not sound and not permissible, because that is a form of usury (ribā), whether the term is fixed or not.
— But if there is no intention or purpose relating to the yield, and the term is fixed and known, then the sale is valid, and the mentioned condition, in ruling, is like an option by stipulation (khiyār al-sharṭ)—or we say: it is khiyār al-sharṭ.
On this basis, benefits (profits/yields) that arise after the sale—both principal and derivative—belong to the one in whom ownership ultimately settles. If the seller brings the price to the buyer and the buyer returns the sold item, the buyer must return to the seller what benefits arose with him.
— If he stipulated rescission to a time not fixed, then the sale is invalid; yet it is permissible to enter into it if there is no intention or purpose toward the yield in the sale, and the benefits belong to the one in whom ownership ultimately settles.
Source: Min Thimār al-ʿIlm wa al-Ḥikmah vol.2