Re: [kitten] New Version Notification for draft-kaduk-kitten-gss-loop-01.txt (fwd)

[Benjamin Kaduk <[e-mail]>]

On Wed, 20 Nov 2013, Benjamin Kaduk wrote:

> I submitted an -01 of the gss-loop document, with sample code.
> There's a duplicate line of source XML in section 2.5 which causes some 
> duplicate text, it's fixed in my git already.  Sorry about that.
>
> Comments welcome :)

We had some discussion on IRC, with Nico, Simo, Tom, Greg, and me.

It's unclear whether the src_name output of gss_accept_sec_context() is 
only intended to be populated on a GSS_S_COMPLETE return; if not, it is 
very easy to leak storage from earlier iterations when multiple calls are 
needed.

We discussed whether (either at the abstract level or the C bindings) it 
is guaranteed to be safe to call gss_release_buffer() twice on the same 
buffer.  It is required to set the length of the buffer to zero (but not 
to zero the value field), but also "Any buffer object returned by a 
GSS-API routine may be passed to gss_release_buffer (even if there is no 
storage associated with the buffer)."  What exactly constitutes a "buffer
object returned by a GSS-API routine" seems subject to interpretation.
(There are many things that could have been done to make this situation 
better, but we don't hvae a time machine.)  Buffers with length zero can 
be generated in lots of ways other than gss_release_buffer() 
(gss_init_sec_context(), gss_accept_sec_context(), gss_unwrap()).

We're pretty sure that GSS_S_CONTINUE_NEEDED will not be set with any 
other major status bits (in the C API).

Nico wanted sample Java code, too (anything we have bindings for, really). 
I don't think I can contribute such code, but would probably take it if 
someone else did.

The send_token()/receive_token() routines are not very good examples.  It 
is probably better to rewrite them to use sendmsg/recvmsg with socketpair, 
which also eliminates the need to add framing with the token length.
(Other stuff about the current implenetation is bad, too, but that's not 
really relevant if it gets rewritten.)

-Ben