What is the ruling on keeping cats at home, and are they pure?

It is permissible to keep cats at home, provided they are fed if confined, or allowed to eat from the vermin of the earth, due to the Prophet's (peace and blessings be upon him) saying: "A woman entered Hellfire because of a cat that she tied up; she did not feed it, nor did she let it eat from the vermin of the earth." The cat itself is pure, and its leftover drink (su'r) is pure and not impure, as he (peace and blessings be upon him) said: "Indeed, it is not impure; it is one of those that roam around you." However, its urine and feces are impure according to the majority of scholars, and one must be careful of them and purify whatever they touch.