From: "Brett Tate" <[EMAIL PROTECTED]>
Since some vendors are validating the position of "critical" within the
Privacy header based upon the following rfc3323 text, I decided to ask a
few questions.
RFC 3323 section 4.2: "When a Privacy header is constructed, it MUST
consist of either the value 'none', or one or more of the values 'user',
'header' and 'session' (each of which MUST appear at most once) which
MAY in turn be followed by the 'critical' indicator."
Does this sentence actually impose an order concerning where "critical"
should be placed within the header?
And if so, did the author and working really intend to impose such an
order restriction? Note that the bnf did not impose such ordering.
It looks like the BNF they really wanted is:
Privacy-hdr = "Privacy" HCOLON priv-list
priv-list = "none"
/ priv-value *(";" priv-value) ?(";" "critical")
priv-value = "header" / "session" / "user" / token
based on section 4.2:
When a Privacy header is constructed, it MUST consist of either the
value 'none', or one or more of the values 'user', 'header' and
'session' (each of which MUST appear at most once) which MAY in turn
be followed by the 'critical' indicator.
and section 5:
When a privacy service performs one of the functions corresponding to
a privacy level listed in the Privacy header, it SHOULD remove the
corresponding priv-value from the Privacy header - otherwise, any
other privacy service involved with routing this message might
unnecessarily apply the same function, which in many cases would be
undesirable. When the last priv-value (not counting 'critical') has
been removed from the Privacy header, the entire Privacy header MUST
be removed from a message.
But the situation is un-analyzable because the writers didn't plan for
extensibility, nor did they make the text match the BNF.
Dale
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