Sayyiduna Ibn Mas'ud (may Allah be pleased with him) said: "There were some practices that the Messenger of Allah (peace and blessings be upon him) used to do which the people have abandoned. One of them is that the imam should give the salam in the funeral prayer just as he gives it in the prayer."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 9986