RFC Errata
RFC 3862, "Common Presence and Instant Messaging (CPIM): Message Format", August 2004
Source of RFC: impp (app)
Errata ID: 3625
Status: Held for Document Update
Type: Technical
Publication Format(s) : TEXT
Reported By: Sergio Garcia
Date Reported: 2013-05-17
Held for Document Update by: Barry Leiba
Date Held: 2013-06-10
Section ABNF defs says:
From-header = "From" ": " [ Formal-name ] "<" URI ">"
; "From" is case-sensitive
It should say:
From-header = %d46 %d72 %d6f %d6g ": " [ Formal-name ] "<" URI ">"
; "From" is case-sensitive
Notes:
All the ABNF from headers are not correct, from ABNF RFC:
Literal text is specified through the use of a string enclosed in quotation marks ("). These strings are case-insensitive and the character set used is (US-)ASCII. Therefore the string “abc” will match “abc”, “Abc”, “aBc”, “abC”, “ABc”, “AbC”, “aBC”, and “ABC”. For a case-sensitive match the explicit characters must be defined: to match “aBc” the definition will be %d97 %d66 %d99.
----------------------- Verifier notes -----------------------
This issue isn't limited to the From header, but applies throughout. However...
Customs for specifying ABNF have become more strict since RFC 3862 was written.
At the time of its writing, it was considered acceptable to use the mechanism here:
specify the string (which would normally be case-insensitive, according to RFC 2234)
and add a comment to note the case-sensitivity. In fact, it was specifically considered
more clear to do that than to specify sequences of hex characters. In addition to the
comments in the ABNF, this variance is noted in Sections 3 and 3.6:
<<
NOTE: Specified text values MUST be used as given, using exactly the
indicated upper- and lower-case letters. In this respect, the ABNF
usage here differs from RFC 2234 [6].
>>
Given that, this is clearly not an *error* in RFC 3862, though a different decision
might be made today, or whenever this document might be revised.
I am therefore marking this report as "held for document update".