Channel window limits

[Ben Harris <bjh21%bjh21.me.uk@localhost>]

In draft-ietf-secsh-connect-23.txt, there seems to be no limit on the 
window size that an implementation can advertise.  While each 
SSH_MSG_CHANNEL_WINDOW_ADJUST can add at most 2^32-1 bytes to the window, 
an implementation can send as many WINDOW_ADJUSTs as it wants.  This is a 
problem because it means that its peer has to keep track of an 
arbitrarily-large window, and in particular one that can't be represented 
by a 32-bit unsigned integer.  I doubt that this is the intention of the 
spec, so I'd suggest the following change:

After:

   After receiving this message, the recipient MAY send the given number
   of bytes more than it was previously allowed to send; the window size
   is incremented.

add:

                    The window MUST NOT be increased above 2^32-1 bytes.

This isn't desperately important, since I doubt any sane implementation 
would violate this constraint anyway, but if there's another draft of 
-connect- I think it should be in there.

Of course, that assumes I'm right about the implication of the current 
draft...

--
Ben Harris