Subject: [xmpp] [Editorial Errata Reported] RFC6121 (5058)

From: RFC Errata System <[email-masked]>
Date: Sun, 2 Jul 2017 09:52:06 -0700 (PDT)

The following errata report has been submitted for RFC6121,
"Extensible Messaging and Presence Protocol (XMPP): Instant Messaging and Presence".

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You may review the report below and at:
http://www.rfc-editor.org/errata/eid5058

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Type: Editorial
Reported by: Florian Schmaus <[email-masked]>

Section: 2.1.6

Original Text
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   2.  A receiving client MUST ignore the stanza unless it has no 'from'
       attribute (i.e., implicitly from the bare JID of the user's
       account) or it has a 'from' attribute whose value matches the
       user's bare JID <user@domainpart>.

Corrected Text
--------------
   2.  A receiving client MUST ignore the stanza unless it has no 'from'
       attribute (i.e., implicitly from the bare JID of the user's
       account) or it has a 'from' attribute whose value matches either
       the user's bare JID <user@domainpart> or the address of an entity
       authorized performing roster pushes.

Notes
-----
RFC 6121 § 2.1.6 2. specifies that roster pushes have to origin from the "user's account", i.e., no 'from' attribute or 'from' attribute matching the user's bare JID. However the Security Warning in the same section states that

      ... this specification allows entities other than the user's server to
      maintain roster information, which means that a roster push might
      include a 'from' address other than the bare JID of the user's
      account.  Therefore, the client MUST check the 'from' address to
      verify that the sender of the roster push is authorized to update
      the roster.

which contradicts what is specified in § 2.1.6 2.

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RFC6121 (draft-ietf-xmpp-3921bis-20)
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Title               : Extensible Messaging and Presence Protocol (XMPP): Instant Messaging and Presence
Publication Date    : March 2011
Author(s)           : P. Saint-Andre
Category            : PROPOSED STANDARD
Source              : Extensible Messaging and Presence Protocol RAI
Area                : Real-time Applications and Infrastructure
Stream              : IETF
Verifying Party     : IESG