Re: draft-stjohns-sipso-05 & transport protocols

On Fri, 03 Oct 2008 07:32:44 -0700
Bill Sommerfeld <sommerfeld <at> sun.com> wrote:

> In a securely-configured MLS environment, systems not running an MLS
> operating system will never receive a packet with an MLS label -- if
> they did, that inherently means that an MLS system somewhere is
> misconfigured and information is flowing in violation of the MLS
> policy.
> 
> It is IMHO not necessary to specify what a label-unaware system should
> do with a labeled packet -- if they get one at all, it's a serious
> error on the part of the sender.
> 
Actually, 793 disagrees:

  The security paramaters may be used even in a non-secure environment  
  (the values would indicate unclassified data), thus hosts in
  non-secure environments must be prepared to receive the security
  parameters, though they need not send them.

The question is how realistic that statement is.

		--Steve Bellovin, http://www.cs.columbia.edu/~smb