Track-specific gear can vary from what you might ride with on the street, but some of this stuff you might already have! Moving from top to bottom, here is what is required in order to ride on the track.
Your back protector must be a CE-approved foam insert at the minimum, but an aftermarket back protector that fits well is preferred.
Gloves should be a gauntlet-style glove that provides full coverage over your wrists and overlaps your leathers. As with all of your gear, the gloves should be in good condition and without holes or damage.
Your boots should be calf-length and provide full ankle coverage. They may be worn under the legs of your pants only if your pant legs are designed for this. Otherwise, your boots must fully overlap the pant legs on your suit.