It's been 20 years today (Oct 16, UTC). Hard to believe.

bzs at bzs at
Wed Oct 17 03:20:16 UTC 2018

On October 16, 2018 at 19:35 mike at (Michael Thomas) wrote:
 > I believe that the IETF party line these days is that Postel was wrong 
 > on this point. Security is one consideration, but there are others.

Security fits into all this, being liberal in what you accept doesn't
mean you do whatever they ask.

Quite the contrary it means make sure your code doesn't roll over dead
or misbehaving just because you received an unexpected input.

Not doing that was exactly what allowed for example buffer overflow

The target software wasn't liberal in what it accepts which is to say
anticipated that someone might send them a very long string and should
either buffer it correctly or truncate it. They assumed they'd only be
sent reasonably short strings.

 > Mike
 > On 10/16/2018 07:18 PM, bzs at wrote:
 > > What it's trying to say is that you have control over your own code
 > > but not others', in general.
 > >
 > > So make your own code (etc) robust and forgiving since you can't edit
 > > others' code to conform to your own understanding of what they should
 > > be sending you.
 > >
 > > I suppose that pre-dates github but nonetheless much of the code which
 > > generates bits flung at you is proprietary and otherwise out of your
 > > control but what you can control is your code's reaction to it.
 > >
 > > And of course the bits you generate which should try to make
 > > conservative assumptions about what they might accept and interpret as
 > > you expect.
 > >
 > > For example just because they sent you a seemingly malformed HTTP
 > > request, and given that 4xx is for error codes, doesn't mean you
 > > should return "420 You must be high!" and expect to be understood.
 > >

        -Barry Shein

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