If you just want tor to bind to the dns port use these interfaces
corenet_tcp_bind_dns_port(tor_t)
corenet_udp_bind_dns_port(tor_t)
Considering these interfaces contain the net_bind_service cap it seems
like you will have to include it. However that isn't a concern since the
statement here only will allow tor to bind to ports labeled dns_port_t.
In this case tcp/udp 53. If you don't want tcp just include the second
of the two interfaces only.
It worked - it is exactly what I was after, thank you! I've just
included the udp bind since tcp/53 is not used by tor.
After I patched tor.te and re-compiled the targeted policy tor started
without any problems.