On 6/7/13 6:02 AM, Brett Tate wrote:
> Because the message is malformed, you can basically act however you want. A
> common philosophy is to be strict sending and lenient receiving. Thus unless
> you have a reason to do otherwise, you might want to allow the message to
> continue.
While I generally agree with that philosophy, it is likely to have
limited success in extreme cases like this.
"Being liberal" effectively means assigning a valid meaning to some
invalid construct. If you guess a meaning that is consistent with the
sender's intent, then all is well.
Sometimes this is straightforward - all reasonable people would infer
the same meaning.
But in other cases there is no clear choice of a valid interpretation.
If there are two likely choices, then maybe you have a 50-50 chance of
doing something more useful than rejecting.
In this case, where there are three request headers, presumably to
proceed you would need to assume it is one of the three. I suppose it is
more likely that either the first or last is the right one than the
middle one, so maybe you pick one of those. What are the odds of doing
something reasonable? I think not very good. (Maybe all three messages
were to have been sent, and all you got were the first lines of two and
the full last message. Then if you process the last one you may
correctly process one of the messages, but without the others things may
still go south.)
IMO this is so broken that you are much better just rejecting it. And
logging it, and later, based on the log, complaining to the sender that
it needs to fix its implementation.
Thanks,
Paul
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