[tcpm] Flaw in RFC793 (Fwd: New Version Notification for draft-gont-tcpm-tcp-seq-validation-03.txt)

[Fernando Gont <[e-mail]>]

Folks,

There is bug in the TCP Sequence Number validation algorithm from
RFC793. Most major implementations have addressed it, but the bug still
remains in our specs.

We got a bit of extra energy to try to get this one fixed. Our I-D
(draft-gont-tcpm-tcp-seq-validation) is available at the usual repository.

We have incorporated some minor edits done after the cut-off here:
<https://www.si6networks.com/publications/drafts/draft-gont-tcpm-tcp-seq-validation-04.txt>
 -- but modulo minor grammar corrections, version -03 is the same.

We'd like to receive feedback from the wg regarding the "problem
statement" (so to speak), and the proposed/described fixes.

Thanks!

Cheers,
Fernando




-------- Forwarded Message --------
Subject: New Version Notification for
draft-gont-tcpm-tcp-seq-validation-03.txt
Date: Mon, 05 Mar 2018 15:43:15 -0800
From: [e-mail]
To: Fernando Gont <[e-mail]>, David Borman
<[e-mail]>


A new version of I-D, draft-gont-tcpm-tcp-seq-validation-03.txt
has been successfully submitted by Fernando Gont and posted to the
IETF repository.

Name:		draft-gont-tcpm-tcp-seq-validation
Revision:	03
Title:		On the Validation of TCP Sequence Numbers
Document date:	2018-03-05
Group:		Individual Submission
Pages:		16
URL:
https://www.ietf.org/internet-drafts/draft-gont-tcpm-tcp-seq-validation-03.txt
Status:
https://datatracker.ietf.org/doc/draft-gont-tcpm-tcp-seq-validation/
Htmlized:
https://tools.ietf.org/html/draft-gont-tcpm-tcp-seq-validation-03
Htmlized:
https://datatracker.ietf.org/doc/html/draft-gont-tcpm-tcp-seq-validation-03
Diff:
https://www.ietf.org/rfcdiff?url2=draft-gont-tcpm-tcp-seq-validation-03

Abstract:
   When TCP receives packets that lie outside of the receive window, the
   corresponding packets are dropped and either an ACK, RST or no
   response is generated due to the out-of-window packet, with no
   further processing of the packet.  Most of the time, this works just
   fine and TCP remains stable, especially when a TCP connection has
   unidirectional data flow.  However, there are three scenarios in
   which packets that are outside of the receive window should still
   have their ACK field processed, or else a packet war will take place.
   The aforementioned issues have affected a number of popular TCP
   implementations, typically leading to connection failures, system
   crashes, or other undesirable behaviors.  This document describes the
   three scenarios in which the aforementioned issues might arise, and
   formally updates RFC 793 such that these potential problems are
   mitigated.




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