How authentic is the Hadith that the Companions rubbed their faces and bodies with the Prophet's — may Allah's peace and blessings be upon him — phlegm during the Treaty of Hudaybiyyah?

The Prophet, peace and blessings be upon him, forbade exaggeration in his praise, and he disliked people standing up for him out of his humility. What the Companions did, seeking blessings from his remnants, peace and blessings be upon him, and demonstrating their immense love, was correct. Its purpose was to provoke Urwah ibn Mas'ud al-Thaqafi, in response to his statement, "And indeed, I see a rabble of people who are likely to flee and abandon you."