Maliks Muwatta Book 020, Hadith Number 009.

Section : Wearing Clothes when in Ihram.

Yahya related to me from Malik from 'Abdullah ibn Dinar that Abdullah ibn Umar said, "The Messenger of Allah, may Allah bless him and grant him peace, forbade anyone in ihram to wear a garment which had been dyed with saffron or yellow dye, and said, 'Anyone that cannot find sandals can wear leather socks, but he should cut them off below the ankles.'"