Segfault in module accessing custom attributes fields

D'AVELLA STEFANO Stefano.DAvella at
Mon Feb 16 15:14:37 CET 2009

Hi all,

I am having some problems in trying to write a little module to handle
some custom attributes. Because I have a project regarding very specific
requirements I preferred to write a module instead of trying to use the
existing ones, so I can know in a better way where to go to change
things when I want a different behaviour.

What I am doing right now is trying to have a testbed with a client, a
proxy and a server, exchanging some custom attributes saved in the users
file of the server and transmitted with auth-accept messages.

The proxy should intercept these new attributes and save them in a
specific syntax in a local file.

I managed to create and transfer successfully the custom attributes and
to have them saved in a local file by the proxy.

The problem is that if these attributes have a string as a value, there
is no problem in reading it using the field vp_strvalue.
If these attributes have the attribute ipv6address, when I try to access
to them using vp_ipv6address I get a segFault. The values are correctly
stored in the packets because I can see them with wireshark and the
client receives them successfully.

In the documentation (the wiki) there is written to access the
attributes through request->packet->vps but I managed to do it only with
request->reply->vps. (initially I wanted to save this local file using
the post-proxy section because I was thinking that it was the best place
to do it (it's an action to do when the proxy receives the reply from
the server) but I couldn't access the right packet through the API and
so I found out that I could do it in the post-auth phase)

I would not want to disturb you too much but the problem is that it
seems to me that there is a bit of lack in the documentation regarding
how write modules in the newer versions of freeradius and so I didn't
know other places to look (I have been looking at the source code for
all the day but maybe I can do it faster if pointed into the right

Thank you in advance for any answer,

Best regards,

D'Avella Stefano
Bell Labs
Centre de Villarceaux
Route de Villejust
91625 NOZAY

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <>

More information about the Freeradius-Users mailing list