Shulchan Arukh, Orach Chayim 450/שולחן ערוך·אורח חיים ת״נ

1The Laws Pertaining to [Chametz Owned by] a Jew and a Non-Jew in Partnership, 7 Seifim If an Jew borrowed a loaf of bread from their fellow Jew before Passover, they must repay it after Passover. Failing to do so would be considered theft.

2If a Jew regularly borrows flour from a non-Jew on a weekly basis with interest, before Passover they should tell the non-Jew to give them either flour or money during the week of Passover. Once an agreement is made in this manner, even though after Passover the non-Jew gives them leavened loaves as a replacement for the flour and money, it is permissible.

3If a Jew and a non-Jew jointly own an oven, the Jew should say to the non-Jew before Passover, "You take your portion of the Passover [baked goods], and I will take mine afterwards."

4If a Jew had an oven, and a non-Jew baked leavened bread in it during Passover, even accepting payment for its use is prohibited, as it would involve benefiting from something prohibited. However, if the payment has already been received, it is permissible to benefit from it.

5One who permits renting their oven to a non-Jew for the purpose of baking matzah in it, and if they bake leavened bread in it, one does not need their services. Note: Similarly, it is permissible to rent them a house for dwelling in, even though they may subsequently bring leavened bread into it. (Agur)

6One may say to a servant on Pesach, "go, take this dinar and buy and eat", even though he knows that he will acquire leavened bread. However, one should not tell him, "Go and eat, and I will compensate." Some permit even this, except if the dinar was given or exchanged directly. Rema: It is forbidden to purchase leavened bread for a non-Jew on Passover, even with the non-Jew's own money. (Rivash, Siman 41)

7It is forbidden to rent utensils to a non-Jew on Passover for the purpose of cooking leavened bread in them. However, one may rent a donkey to a non-Jew for the transportation of leavened bread. Rema: Some permit using chametz utensils to heat water or for washing purposes, as well as benefiting from other non-food-related uses, and this is the customary practice. (Tosafot, Perek Ein Ma'amidin; Mordechai, Perek Kol Sha'ah)