Warner, 32, becomes the fourth short term goalie to come to Carrow Road this season following Lee Camp, Jamie Ashdown and David Marshall, and will provide competition for Paul Gallacher.
Marshall, who had been on loan from Celtic, has returned to Scotland after an injury sustained in the FA Cup clash with Chelsea ruled him out until the summer.
Warner, who began his career at Liverpool before making his name with Millwall, has already featured in the Championship this season after a spell with Leeds. He joined Fulham from Cardiff. During his days at Anfield he warmed the bench to such an extent that he earned the nickname 'Bonus' for his habit of continually taking home his win dividend having failed to get onto the pitch.