She asked Umm Salama what garments a woman should pray in. Umm Salama replied, "She prays in a head covering and a long shift that covers the tops of her feet."
حدثنا القعنبي عن مالك
أنها سألت أم سلمة ماذا تصلي فيه المرأة من الثياب فقالت تصلي في الخمار والدرع السابغ الذي يغيب ظهور قدميها
[Its chain is daif] Bayhaqi narrated it, 2/232, and it is found in Muwatta (Yahya), 1/142.Muhammad bin Zayd is of unknown status, though Hakim graded it sahih on her authority, 1/250, and Dhahabi agreed.