Subject: [Errata Held for Document Update] RFC7230 (5257)

From: RFC Errata System <[email-masked]>
Date: Mon, 23 Aug 2021 09:31:32 -0700 (PDT)

The following errata report has been held for document update 
for RFC7230, "Hypertext Transfer Protocol (HTTP/1.1): Message Syntax and Routing". 

--------------------------------------
You may review the report below and at:
https://www.rfc-editor.org/errata/eid5257

--------------------------------------
Status: Held for Document Update
Type: Technical

Reported by: Erwin Pe <[email-masked]>
Date Reported: 2018-02-07
Held by: Francesca Palombini (IESG)

Section: 7

Original Text
-------------
For compatibility with legacy list rules, a recipient MUST parse and
ignore a reasonable number of empty list elements: enough to handle
common mistakes by senders that merge values, but not so much that
they could be used as a denial-of-service mechanism.  In other words,
a recipient MUST accept lists that satisfy the following syntax:

  #element => [ ( "," / element ) *( OWS "," [ OWS element ] ) ]

  1#element => *( "," OWS ) element *( OWS "," [ OWS element ] )

Corrected Text
--------------
For compatibility with legacy list rules, a recipient MUST parse and
ignore a reasonable number of empty list elements: enough to handle
common mistakes by senders that merge values, but not so much that
they could be used as a denial-of-service mechanism.  In other words,
a recipient MUST accept lists that satisfy the following syntax:

  #element => [ ( ("," OWS element) / element ) *( OWS "," [ OWS 
    element ] ) ]

  1#element => *( "," OWS ) element *( OWS "," [ OWS element ] )

Notes
-----
With the current ABNF rule for #element, and using token as an element, the construction:

    ",     foobar" 

cannot be derived from #element, but can be derived from 1#element. (legacy list rule)
Since #element is meant to be a superset of 1#element, lists derived from 1#element should satisfy the #element rule as well.

--------------------------------------
RFC7230 (draft-ietf-httpbis-p1-messaging-26)
--------------------------------------
Title               : Hypertext Transfer Protocol (HTTP/1.1): Message Syntax and Routing
Publication Date    : June 2014
Author(s)           : R. Fielding, Ed., J. Reschke, Ed.
Category            : PROPOSED STANDARD
Source              : Hypertext Transfer Protocol Bis APP
Area                : Applications
Stream              : IETF
Verifying Party     : IESG