Hi all,
I've been working on re-adding GSS/Kerberos authentication support to the PROXY (V4) FSAL, with a mind to eventually also adding Kerberos delegation support for completeness. I've been having some issues I was hoping to get some feedback on.
The first issue I've been having is to do with the GSS code in libntirpc.
I'm calling authgss_ncreate_default with a valid CLIENT * and service name, and hopefully a reasonable struct rpc_gss_sec. This fails, because the call to gss_verify_mic inside authgss_refresh fails. This appears to be because authgss_verify fills a relevant buffer (gd->gc_wire_verf) with <empty>, which originally comes from cc_verf in the clnt code (via the start of authgss_validate). Specifically I'm looking at clnt_req's cc_verf which gets used for AUTH_VALIDATE in clnt_generic.c, and always seems to have the same "_null_auth" value - which seems surprising to me! If anyone can give me some insight into what exactly cc_verf is supposed to contain that might help me fix it. Working around it by ignoring the result of gss_verify_mic does seem to work OK.
The second issue is to do with the structure of the PROXY FSAL.
It appears that it largely handles requests "manually", calling the relevant xdr_* functions, and reading/writing to sockets itself. The GSS auth code on the other hand, seems to require use of CLIENT *, which in my understanding means handing responsibility for the socket to that CLIENT *. These two approaches appear incompatible to me. I've made some reasonable progress rewriting PROXY with clnt_req_* functions, similar to nfs_rpc_callback.c, but if anyone has any feedback on a) why the original approach (ffilz suggests those functions didn't used to be threadsafe?) b) the most sensible thing to do now, it would be very much appreciated.
Anyway any feedback is very welcome, I'm very new to both Ganesha and GSS/Kerberos.
Many thanks,
Jo