define object and subject type transitions:
object transition
type_transition sshd_t tmp_t:{ dir file lnk_file sock_file fifo_file } sshd_tmp_t;
subject transition
type_transition sshd_t shell_exec_t:process user_t;
SELinux supports a lot of useful transition macros, e.g. domain_auto_trans, file_type_auto_trans
file_type_auto_trans(sshd_t, tmp_t, sshd_tmp_t) domain_auto_trans(sshd_t, shell_exec_t, user_t)
