Re: [dnssd] Genart last call review of draft-ietf-dnssd-push-20

Michael Richardson <mcr+ietf@sandelman.ca> Sun, 14 July 2019 21:05 UTC

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From: Michael Richardson <mcr+ietf@sandelman.ca>
To: Ted Lemon <mellon@fugue.com>
cc: Stuart Cheshire <cheshire=40apple.com@dmarc.ietf.org>, Eric Rescorla <ekr@rtfm.com>, DNSSD <dnssd@ietf.org>, draft-ietf-dnssd-push.all@ietf.org, David Schinazi <dschinazi.ietf@gmail.com>, Tom Pusateri <pusateri@bangj.com>, Robert Sparks <rjsparks@nostrum.com>
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Comments: In-reply-to Ted Lemon <mellon@fugue.com> message dated "Thu, 11 Jul 2019 13:19:05 -0400."
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Date: Sun, 14 Jul 2019 17:05:26 -0400
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Subject: Re: [dnssd] Genart last call review of draft-ietf-dnssd-push-20
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Ted Lemon <mellon@fugue.com> wrote:
    > forging an RST to the server. We should discuss whether this is a
    > serious concern that we need to take into account. If it is, then using
    > close_notify would protect against this iff the server ignores TCP RSTs
    > for active TLS sessions.

I'm unaware of TCP stacks that can turn off RSTs on a per-socket basis.
Is this commonly available now and I'm just ignorant of it?

I imagine that is the only way the application could inform the kernel that
TLS is active.

I guess a filter could drop RSTs to port 853, and assume it's always TLS.

Securing TCP against fake RSTs is something the TCP-AO was designed to do.
AFAIK, we never defined a way to key TCP-AO from TLS.

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