R' Aryeh Kaplan in The Living Torah quotes four opinions as to the identity of keneh bosem (page pictured below, paragraph beginning "fragrant cane"): calamus (Septuagint, Rambam Peirush HaMishnayos, et. al.), Cympopogan (Rambam Mishneh Torah), Cannabis ("some"), and Cinnamon (Radak, Abarbanel).
As he does not actually quote an opinion that identifies this with Cannabis, is there anyone who explicitly does so?
fragrant cane Keneh bosem in Hebrew. Ancient sources identify this with the sweet calmus (Septuagint; Rambam on Kerithoth 1:1; Saadia; Ibn Janach). This is the sweetflag or flag-root, Acoras calamus which grows in Europe. It appears that a similar species grew in the Holy Land, in the Hula region in ancient times (Theophrastus, History of Plants 9:7). Other sources apparently indicate that it was the Indian plant, Cympopogan martini, which has the form of red straw (Yad, Kley HaMikdash 1:3). On the basis of cognate pronunciation and Septuagint readings, some identify Keneh bosem with the English and Greek cannabis, the hemp plant.
There are, however, some authorities who identify the 'sweet cane' with cinnamon bark (Radak, Sherashim). Some say that kinman is the wood, and keneh bosem is the bark (Abarbanel).