[Acme] Generating nonces probabilistically in 6.4.1. Replay-Nonce

[Erica Portnoy]

In section 6.4.1. Replay-Nonce, it states: "The server should generate
the value provided in Replay-Nonce in such a way that they are unique to
each message, with high probability."

Should this not be: "The server MUST generate the value provided in
Replay-Nonce in such a way that they are unique to each message."

This is actually two separate items:
- First, that the server must, not should, generate a unique
Replay-Nonce. I can't imagine that we're ok with the spec allowing a
server to come under replay attacks, so this should probably be MUST.
- Second, do Replay-Nonces need to be certainly unique to each message?
Or are we merely attempting to mostly rule out replay attacks? If we
want to disable them completely, not just with extremely high
probability, then we should remove "with high probability".

Best,
Erica Portnoy

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Re: [Acme] Fwd: New Version Notification for draft-shoemaker-acme-ip-00.txt

[Roland Bracewell Shoemaker]

On 03/27/2017 04:28 PM, Richard Barnes wrote:
> Thanks, Roland.  Interesting draft.
> 
> Couple of first reactions:
> 
> - Why use the target of the PTR instead of just provisioning the TXT
> record directly in the reverse DNS.  (Is there some restriction in the
> spec for reverse DNS that says it's only PTR?)  It seems like by using
> the PTR target, your security analysis gets much more complicated.
> 

The original reason for this was that I held the belief that there was
an RFC that set restrictions on the record types that should exist in
the reverse zones (i.e. PTR/CNAME/NS/SOA) only. After looking through
relevant documents for the last hour though I can't actually find
anything that states this and a number of example zones do seem to
contain other types, notably TXTs.

Based on this I think it does makes sense to remove the use of the PTR
target and just require the provisioning of a TXT record at the reverse
mapping node.

> - For the re-use of "http-01", you should probably specify the contents
> of the Host header.  (Main ACME should probably clarify that for DNS, if
> it's not clear already.)
> 

Good point.

> On Mon, Mar 27, 2017 at 4:38 PM, Roland Shoemaker
> > wrote:
> 
> Probably of interesting to some people here, would love to hear your
> thoughts.
> 
>  Forwarded Message 
> Subject: New Version Notification for draft-shoemaker-acme-ip-00.txt
> Date: Mon, 27 Mar 2017 13:30:19 -0700
> From: internet-dra...@ietf.org 
> To: Roland Bracewell Shoemaker  >, Roland
> Shoemaker >
> 
> 
> A new version of I-D, draft-shoemaker-acme-ip-00.txt
> has been successfully submitted by Roland Bracewell Shoemaker and posted
> to the
> IETF repository.
> 
> Name:   draft-shoemaker-acme-ip
> Revision:   00
> Title:  ACME IP Identifier Validation Extension
> Document date:  2017-03-27
> Group:  Individual Submission
> Pages:  6
> URL:
> https://www.ietf.org/internet-drafts/draft-shoemaker-acme-ip-00.txt
> 
> Status:   
>  https://datatracker.ietf.org/doc/draft-shoemaker-acme-ip/
> 
> Htmlized: 
>  https://tools.ietf.org/html/draft-shoemaker-acme-ip-00
> 
> Htmlized:
> https://datatracker.ietf.org/doc/html/draft-shoemaker-acme-ip-00
> 
> 
> 
> Abstract:
>This document specifies identifiers and challenges required to enable
>the Automated Certificate Management Environment (ACME) to issue
>certificates for IP addresses.
> 
> 
> 
> 
> Please note that it may take a couple of minutes from the time of
> submission
> until the htmlized version and diff are available at tools.ietf.org
> .
> 
> The IETF Secretariat
> 
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> 
> 

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Re: [Acme] Fwd: New Version Notification for draft-shoemaker-acme-ip-00.txt

[Richard Barnes]

Thanks, Roland.  Interesting draft.

Couple of first reactions:

- Why use the target of the PTR instead of just provisioning the TXT record
directly in the reverse DNS.  (Is there some restriction in the spec for
reverse DNS that says it's only PTR?)  It seems like by using the PTR
target, your security analysis gets much more complicated.

- For the re-use of "http-01", you should probably specify the contents of
the Host header.  (Main ACME should probably clarify that for DNS, if it's
not clear already.)

On Mon, Mar 27, 2017 at 4:38 PM, Roland Shoemaker 
wrote:

> Probably of interesting to some people here, would love to hear your
> thoughts.
>
>  Forwarded Message 
> Subject: New Version Notification for draft-shoemaker-acme-ip-00.txt
> Date: Mon, 27 Mar 2017 13:30:19 -0700
> From: internet-dra...@ietf.org
> To: Roland Bracewell Shoemaker , Roland
> Shoemaker 
>
>
> A new version of I-D, draft-shoemaker-acme-ip-00.txt
> has been successfully submitted by Roland Bracewell Shoemaker and posted
> to the
> IETF repository.
>
> Name:   draft-shoemaker-acme-ip
> Revision:   00
> Title:  ACME IP Identifier Validation Extension
> Document date:  2017-03-27
> Group:  Individual Submission
> Pages:  6
> URL:
> https://www.ietf.org/internet-drafts/draft-shoemaker-acme-ip-00.txt
> Status: https://datatracker.ietf.org/doc/draft-shoemaker-acme-ip/
> Htmlized:   https://tools.ietf.org/html/draft-shoemaker-acme-ip-00
> Htmlized:
> https://datatracker.ietf.org/doc/html/draft-shoemaker-acme-ip-00
>
>
> Abstract:
>This document specifies identifiers and challenges required to enable
>the Automated Certificate Management Environment (ACME) to issue
>certificates for IP addresses.
>
>
>
>
> Please note that it may take a couple of minutes from the time of
> submission
> until the htmlized version and diff are available at tools.ietf.org.
>
> The IETF Secretariat
>
> ___
> Acme mailing list
> Acme@ietf.org
> https://www.ietf.org/mailman/listinfo/acme
>
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[Acme] Generating nonces probabilistically in 6.4.1. Replay-Nonce

[Jacob Hoffman-Andrews]

Forwarding on behalf of Erica Portnoy.

I agree, the uniqueness should be a MUST, but I think "high probability"
should stay so random generation of nonces is acceptable. PR:
https://github.com/ietf-wg-acme/acme/pull/289


 Forwarded Message 
Subject:Generating nonces probabilistically in 6.4.1. Replay-Nonce
Resent-Date:Fri, 24 Mar 2017 18:19:35 -0700 (PDT)
Resent-From:alias-boun...@ietf.org
Resent-To:  r...@ipv.sx, j...@eff.org, jdkas...@umich.edu
Date:   Fri, 24 Mar 2017 18:03:53 -0700
From:   erica 
To: draft-ietf-acme-a...@ietf.org



In section 6.4.1. Replay-Nonce, it states: "The server should generate 
the value provided in Replay-Nonce in such a way that they are unique to 
each message, with high probability."

Should this not be: "The server MUST generate the value provided in 
Replay-Nonce in such a way that they are unique to each message."

This is actually two separate items:
- First, that the server must, not should, generate a unique 
Replay-Nonce. I can't imagine that we're ok with the spec allowing a 
server to come under replay attacks, so this should probably be MUST.
- Second, do Replay-Nonces need to be certainly unique to each message? 
Or are we merely attempting to mostly rule out replay attacks? If we 
want to disable them completely, not just with extremely high 
probability, then we should remove "with high probability".

Best,
Erica Portnoy


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[Acme] Fwd: New Version Notification for draft-shoemaker-acme-ip-00.txt

[Roland Shoemaker]

Probably of interesting to some people here, would love to hear your
thoughts.

 Forwarded Message 
Subject: New Version Notification for draft-shoemaker-acme-ip-00.txt
Date: Mon, 27 Mar 2017 13:30:19 -0700
From: internet-dra...@ietf.org
To: Roland Bracewell Shoemaker , Roland
Shoemaker 


A new version of I-D, draft-shoemaker-acme-ip-00.txt
has been successfully submitted by Roland Bracewell Shoemaker and posted
to the
IETF repository.

Name:   draft-shoemaker-acme-ip
Revision:   00
Title:  ACME IP Identifier Validation Extension
Document date:  2017-03-27
Group:  Individual Submission
Pages:  6
URL:
https://www.ietf.org/internet-drafts/draft-shoemaker-acme-ip-00.txt
Status: https://datatracker.ietf.org/doc/draft-shoemaker-acme-ip/
Htmlized:   https://tools.ietf.org/html/draft-shoemaker-acme-ip-00
Htmlized:
https://datatracker.ietf.org/doc/html/draft-shoemaker-acme-ip-00


Abstract:
   This document specifies identifiers and challenges required to enable
   the Automated Certificate Management Environment (ACME) to issue
   certificates for IP addresses.




Please note that it may take a couple of minutes from the time of submission
until the htmlized version and diff are available at tools.ietf.org.

The IETF Secretariat

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