Re: [DNSOP] [Ext] I-D Action: draft-ietf-dnsop-svcb-https-05.txt

Paul Wouters <paul@nohats.ca> Mon, 10 May 2021 20:04 UTC

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Date: Mon, 10 May 2021 16:04:21 -0400 (EDT)
From: Paul Wouters <paul@nohats.ca>
To: dnsop <dnsop@ietf.org>
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Subject: Re: [DNSOP] [Ext] I-D Action: draft-ietf-dnsop-svcb-https-05.txt
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On Mon, 10 May 2021, Joe Abley wrote:

>>>    $ORIGIN example.com
>>>    @   SVCB   1 foo
>>> key6="\032\001\013\184\000\000\000\000\000\000\000\000\\\\,\000"
>>>    ; a.k.a.   ipv6hint=2001:db8::5c5c:2c00
>>
>> A zone owner/editor would never even think of typing in IP addresses
>> like that.
>
> Right, but an attacker who wants to take advantage of the impact of that observation in the construction of some parser might, which is why it's a security concern.

Some DN / RDN / CN parsing tools have hthis issue too and some allow a
comma with an additional masking comma, eg  OU=testing,,security, O=Mayhem

Then other code can just never ever allow masking, double masking,
backslshing, single or double quotes or what not.

Paul