MySQL 5.7 Reference Manual Including MySQL NDB Cluster 7.5 and NDB Cluster 7.6
The MySQL grant system takes stored routines into account as follows:
          The CREATE ROUTINE privilege is
          needed to create stored routines.
        
          The ALTER ROUTINE privilege is
          needed to alter or drop stored routines. This privilege is
          granted automatically to the creator of a routine if
          necessary, and dropped from the creator when the routine is
          dropped.
        
          The EXECUTE privilege is
          required to execute stored routines. However, this privilege
          is granted automatically to the creator of a routine if
          necessary (and dropped from the creator when the routine is
          dropped). Also, the default SQL SECURITY
          characteristic for a routine is DEFINER,
          which enables users who have access to the database with which
          the routine is associated to execute the routine.
        
          If the
          automatic_sp_privileges
          system variable is 0, the
          EXECUTE and
          ALTER ROUTINE privileges are
          not automatically granted to and dropped from the routine
          creator.
        
          The creator of a routine is the account used to execute the
          CREATE statement for it. This might not be
          the same as the account named as the
          DEFINER in the routine definition.
        
      The server manipulates the mysql.proc table in
      response to statements that create, alter, or drop stored
      routines. Manual manipulation of this table is not supported.