Questions about network_macros [ was: Re: more ptal_t (strict) ]

Tom London selinux at
Mon May 30 01:23:56 UTC 2005

On 5/29/05, Ivan Gyurdiev <ivg2 at> wrote:
> > +can_network_tcp(ptal_t, self)
> Can someone clarify how networking rules are supposed to work.
> 1) There is poor documentation on all network macros - they all
> take 2 or 3 arguments, and only one is documented.
> 2) There is optional socket type and port type. Looking at policy,
> those don't seem to be used very often. Is that a bad thing?
> 3) Then there's name_connect and name_bind.
> Why are those not incorporated in any network macros,
> but at the same time you have the ability to specify a port type
> in base_can_network.
> Basically I've been writing:
> can_network_client(domain)
> allow domain specific_port:tcp_socket/udp_socket name_connect;
> can_network_server(domain)
> allow domain specific_port:tcp_socket/udp_socket name_bind;
> Now this seems wrong - what's are the proper rules?
> It seems to me that name_bind and name_connect should be integrated
> w/ network_macros, and I should specify a port/socket_type on network
> macros that I invoke.
> ....
> Then there wouldn't be need for special purpose name_connect macros
> like can_resolve, can_ldap...
> define(`can_ldap',`
> ifdef(`slapd.te',`
> can_network_client_tcp($1, `ldap_port_t')
> allow $1 ldap_port_t:tcp_socket name_connect;
> ')
> ')
> Why does slapd.te have to be present to name_connect to a ldap port?
> This seems wrong... I need to connect to ldap from evolution.
> The ldap port is not defined in slapd.te.
> > +allow ptal_t port_t:tcp_socket name_bind;
> This lets it bind to any port... why not a specific one?
> --
> Ivan Gyurdiev <ivg2 at>
> Cornell University
My error on can_network_tcp().  Should be 'can_network_tcp(ptal_t)'. I
agree with your comment on 'name_bind'.

I thought 'can_network_tcp()' was just a combination of the client and
server cases.

Regarding specific port.  Yeah, you're correct.  ptal-photod wants to
connect on 5703:
May 28 10:01:53 fedora kernel: audit(1117299713.078:31): avc:  denied 
{ name_bind } for  pid=3576 comm="ptal-photod" src=5703
scontext=root:system_r:ptal_t tcontext=system_u:object_r:port_t

Havent't done this before.

So I do this by adding something like the following to net_contexts?
ifdef(`cups.te', `portcon tcp 5703 system_u:object_r:ptal_port_t')

and add something like the following to types/network.te?
ifdef(`cups.te', `type ptal_port_t, port_type, reserved_port_type;')

and then change 'allow ptal_t port_t:tcp_socket name_bind' to?
allow ptal_t ptal_t:ptal_port_t name_bind;

Is that right? A better/simpler way to do this?
Tom London

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