Hare Krishna,
Not that the injunctions regarding the Ten Offenses to the Holy Name were actually spoken by Lord Krishna directly ...
They are listed in the Padma Purana - the vedic literature from which Sri Damodarataksam also comes. This Purana is said to "contain the glory of Srimad-Bhagavatam." Such literatures are authorized, as they glorify Lord Krishna, the Supreme Personality of Godhead.
Here's a link for you to read the particular section from Padma Purana:
10 Offenses To The Holy Name