GSOC 2017 Progress Report #7

[Dimitris Gravanis]

Progress Report #7 22-07-2017 
<https://dimgrav.blogspot.gr/2017/07/progress-report-7.html>

_gss-tsig:_ <https://github.com/dimgrav/Samba-GSOC2017/tree/master/gss-tsig>

  * memset() in dns_empty_tsig() to initialize empty rdata fields in
    client_crypto.c
  * full tsig generation and server mac validation in client_crypto.c
  * minor changes in libcli_crypto.h

*client_crypto.c*

I used WERROR in accordance to error handling in the server code. Is 
there an advantage in using NTSTATUS instead?

Use of memset() must be reviewed, as it uses pointers and I am not fully 
aware if all related fields in rdata are declared as such.

dns_find_tkey() is used as coded for its respected use in 
/source4/dns_server/dns_server.c. It has been suggested that I use a new 
linked-list to manipulate the cache, though I've come across this 
<http://www.zentut.com/c-tutorial/c-linked-list/#C_Linked_List_implementation> 
tutorial, which suggests that linked-lists may not be ideal for locating 
specific nodes in the cache:

"The linked list data structure is designed to be efficient for 
insertion or removal of elements from any position in the list./However 
other operations such as getting the last element or finding an element 
that stores specific data _requires scanning most or all the elements_ 
in the list/."

_tcp-cli:_ <https://github.com/dimgrav/Samba-GSOC2017/tree/master/tcp-cli>

  * added tcp connection handling in dns_tcp.c
  * tstream_read_pdu_blob_send/recv() loop implemented in dns_tcp.c
  * added missing callback assignments in dns_tcp.c
  * changes in libdns_tcp to accomodate changes

*dns_tcp.c*

The send/recv loop should probably be reviewed, since 
tstream_read_pdu_blob does not appear to be defined in tsocket, so I'm 
not sure I've got it right.

Additionally, dns_tcp_req_done() is probably wrong, but I'd need some 
verification on this.


I'm starting writing tests for gss-tsig tomorrow, as I'm quite confident 
that the code appears to be a solid foundation for fine-tuning.

The TCP call handler needs a bit of work, so that I can add signature 
generation.


As always, feedback would be greatly appreciated.

Temporary GitHub repo here <https://github.com/dimgrav/Samba-GSOC2017>.


Have a great weekend,

Dimitris