Jabir bin Abdullah (may Allah be pleased with them both) said that the Messenger of Allah (peace and blessings be upon him) touched the Black Stone and kissed it, and touched the Yamani Corner and kissed his hand.
Umar bin Qays al-Makki is da'if (weak). A report has also been narrated about kissing it (the Yamani Corner) that is likewise not established.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحج / 9235