Fix for bug where originating CoA requests causes segfault if proxying is disabled.

[paterry]

If FreeRADIUS 3.0.11 is configured to originate CoA requests in response to certain packets using the following files:

etc/raddb/sites-enabled/default
etc/raddb/sites-enabled/originate-coa
etc/raddb/clients.conf

it will segfault if the following line is present in etc/raddb/radiusd.conf:

proxy_requests = no

In src/main/process.c request_coa_originate() calls insert_into_proxy_hash(), which expects the global variable proxy_list to be initialised. It is initialised in radius_event_start(), but only if main_config.proxy_requests is true.

The patch adds the following configuration parameter:

originate_coa_requests = yes / no

If it is set to 'yes' the proxy_list global will be initialised if the proxy code hasn't already done so. Otherwise CoA requests will not be originated. It defaults to 'yes'.

[alandekok]

The simpler fix is to disallow originate_coa unless proxy_requests = yes.

Sending CoA packets is proxying. So there's no point in allowing CoA when proxying is disallowed.

There is no problem (security, performance, etc.) when allowing proxy_requests = yes, but never doing proxying.