(15) باب لُبْسِ الْخُفَّيْنِ لِلْمُحْرِمِ إِذَا لَمْ يَجِدِ النَّعْلَيْنِ
Narrated `Abdullah:
Allah's Messenger (ﷺ) was asked what sort of clothes a Muhrim should wear. He replied, "He should not wear a shirt, turbans, trousers, a hooded cloak, or a dress perfumed with saffron or Wars; and if slippers are not available he can wear Khuffs (socks made from thick fabric or leather) but he should cut them so that they reach below the ankles.
Reference: Sahih al-Bukhari 1842
In-book reference: Book 28, Hadith 22
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 3, Book 29, Hadith 68