Re: [TLS] I-D Action:draft-ietf-tls-rfc4366-bis-09.txt

[Nikos Mavrogiannopoulos <[e-mail]>]

Peter Gutmann wrote:
> Nikos Mavrogiannopoulos <[e-mail]> writes:
> 
>> I have no exact information about where 2^14 the limit itself is coming from 
>> (it dates all the way back to SSL 3.0), but I can imagine it has something to 
>> do with values 2^15 and up being negative if signed 16-bit integers are used. 
> 
> It may also have been because it's a convenient upper bound for memory 
> buffers, particularly in embedded systems.  There's an awful lot of SSL 
> running in little controller boards for various devices, having to allocate 
> potentially 2 x 64kB buffers (the limit for 16-bit lengths) instead of 2 x 
> 16kB would have been a deal-breaker for some of them.  In addition, as you
> say, on 16-bit systems (some of which are still in use today, again in 
> embedded devices) you run into risky conditions once you get close to 2^15.

This is not really a stopper. Since it is being negotiated it should be
obvious that those clients will accept the default or less. The
intention is to give choice to more capable clients and servers.


regards,
Nikos