Subject: WG Action - 1 week last call [LL14] Add security consideration for the threat if the same address is used for multiple interfaces - force reconfiguration will effect multiple links

From: Erik Guttman <[email-masked]>
Date: Thu, 3 Apr 2003 18:19:31 +0200 (CEST)

This item is entering a 1 week last call discussion period, ending Apr
10, 2003.  Please send a comment to the working group list indicating
whether you accept or reject the proposal, including more information if
appropriate.  Please use the subject line:

  [LL14] Add security consideration for the threat ...

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If LL15 is accepted, this security consideration no longer applies,
right?
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Description of Issue  Add security consideration for the threat if the
same address is used for multiple interfaces - force reconfiguration
will effect multiple links    
Submitter Name  Erik Nordmark    
Submitter Email Address  [email-masked]    
Date first submitted 6 Feb 2003
Reference
http://www.merit.edu/mail.archives/zeroconf/2002-10/msg00000.html
Comment Type ['T'echnical | 'E'ditorial]  T    
Priority['S' Must fix | '1' Should fix | '2' May fix ]  S    
Section  5
Rationale/Explanation of issue:   
Lengthy description of problem:
section 3.2:
Some operating systems have networking APIs that allow
applications to specify network interfaces by name, index value,
or other local identifier, and to identify interfaces this way
both for incoming and outgoing packets/connections. For operating
systems that have this capability (and have application software
that makes use of it) it is sufficient to configure all interfaces
with a single common IPv4 link-local address, and defend that
address on all interfaces.

Add warning that uses the same address on all interfaces makes the host
more suceptible to attacks and other reasons for duplicate addresses
being detected late, resulting in a shorter lifetime for the link-local
addresses. Using a separate address per interface limits the "damage"
in such a case to a single link. 

Requested Change: 

Change text to: 

Some operating systems have networking APIs that allow applications to
specify network interfaces by name, index value, or other local
identifier, and to identify interfaces this way both for incoming and
outgoing packets/connections. For operating systems that have this
capability (and have application software that makes use of it) it is
not necessary to ensure that all local interfaces have distinct
addresses, nor to ensure that all local interfaces have addresses that
are distinct with respect to ALL links to which the host has
connectivity. Such a host may choose to initially configure all
interfaces with a single common IPv4 link-local address, and defend that
address on all interfaces, but in the event that an address conflict is
detected on a particular link, only the interface(s)  directly connected
to that link should select a new address as described in Section 2.
Reconfiguring all interfaces to a new common IPv4 link-local address
could needlessly break TCP connections that may have already been
established on other links where there is no address conflict. 

Erik Guttman
Zeroconf WG chair

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From: "Philip Nye" <[email-masked]>
Date: Fri, 4 Apr 2003 11:14:37 -0000

I support LL14

Philip

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From: "Philip Nye" <[email-masked]>
Date: Fri, 4 Apr 2003 11:31:25 -0000

> From: "Philip Nye" <[email-masked]>
> I support LL14

I thought I did until I read LL15 and LL30 better. I shouldn't be in so much
hurry! - see my reply to LL30.

Philip

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From: Erik Guttman <[email-masked]>
Date: Fri, 11 Apr 2003 14:54:45 +0200 (CEST)

Action: Reject
Since LL15 has been accepted - this issue is no longer relevent.

Erik Guttman
ZEROCONF WG Chair

---------------------------------------------------------

On Thu, 3 Apr 2003, Erik Guttman wrote:
> Date: Thu, 3 Apr 2003 18:19:31 +0200 (CEST)
> From: Erik Guttman <[email-masked]>
> To: [email-masked]
> Cc: [email-masked]
> Subject: WG Action - 1 week last call [LL14] Add security consideration for the threat if the same address is used for multiple interfaces - force reconfiguration will effect multiple links
> 
> 

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