Musnad Ahmad 27:387

Mu'adh narrated to us, Ibn 'Awn narrated to us, from Nafi', from Ibn 'Umar, who said: A man called out to the Prophet, peace and blessings of Allah be upon him: "What garments should the *muhrim* (pilgrim in ihram) wear?" He said: "Do not wear the shirt, nor the turban, nor the hooded cloaks (*baranis*), nor the trousers, nor the leather socks (*khuffayn*), unless one does not have sandals; if one does not have sandals, then [he may wear] leather socks cut below the ankles. And do not wear any garment touched by *wars* (a yellow dye)." Ibn 'Awn said: Either he said "dyed," or he said "touched by *wars* and saffron." Ibn 'Awn said: And in Nafi's book it says "touched by."