The Messenger of Allah ﷺ was asked what clothing a person in the state of ihram may wear. He replied, "He must not wear a shirt, a hooded cloak, trousers, a turban, or any garment touched by wars dye or saffron. Nor may he wear leather socks, unless he cannot find sandals. If he cannot find sandals, let him cut them so that they fall below the ankles."
أخبرنا محمد بن منصور عن سفيان عن الزهري
سئل رسول الله ﷺ ما يلبس المحرم من الثياب قال لا يلبس القميص ولا البرنس ولا السراويل ولا العمامة ولا ثوبا مسه ورس ولا زعفران ولا خفين إلا لمن لا يجد نعلين فإن لم يجد نعلين فليقطعهما حتى يكونا أسفل من الكعبين
Sourcing. Bukhari related it in the Book of Clothing, chapter on turbans, hadith no. 5806, and Muslim in the Book of Hajj, chapter on what is permitted etc., hadith no. 2/1177, both from the hadith of Sufyan bin Uyayna with this chain, concerning what the one in ihram for Hajj or Umrah may and may not wear. It is also found in Kubra, hadith no. 3647.