Re: [quicwg/base-drafts] Discard Initial keys as soon as possible (#2045)

ekr <notifications@github.com> Sat, 24 November 2018 04:34 UTC

Return-Path: <noreply@github.com>
X-Original-To: quic-issues@ietfa.amsl.com
Delivered-To: quic-issues@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id BCF45130DD6 for <quic-issues@ietfa.amsl.com>; Fri, 23 Nov 2018 20:34:28 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -9.46
X-Spam-Level:
X-Spam-Status: No, score=-9.46 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIMWL_WL_HIGH=-1.46, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, HTML_MESSAGE=0.001, MAILING_LIST_MULTI=-1, RCVD_IN_DNSWL_HI=-5, SPF_PASS=-0.001] autolearn=ham autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (1024-bit key) header.d=github.com
Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 8Wyyrd5DDI59 for <quic-issues@ietfa.amsl.com>; Fri, 23 Nov 2018 20:34:27 -0800 (PST)
Received: from out-2.smtp.github.com (out-2.smtp.github.com [192.30.252.193]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id BBDD4130DD0 for <quic-issues@ietf.org>; Fri, 23 Nov 2018 20:34:26 -0800 (PST)
Date: Fri, 23 Nov 2018 20:34:25 -0800
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=github.com; s=pf2014; t=1543034065; bh=KtghZk3BEwl2UjIviqmLrF/EBrURh38vJOiIktoqRYg=; h=Date:From:Reply-To:To:Cc:In-Reply-To:References:Subject:List-ID: List-Archive:List-Post:List-Unsubscribe:From; b=lYfHDnWaCEcADHyhO3w/BQNVDue+DkPR7SpnBiHgsyRts2YQOT6B0Z7n+JEL/LQ8U 4QiTbo77HNKAy36gubWWQUq9zPJIPqdx+G7mHeKPyFR4+P9AEOe6UugR7xe2llLfKv +TuEX9v+SAQ5W9WTYUT2uCN4y6LuvamnqxqYxnDY=
From: ekr <notifications@github.com>
Reply-To: quicwg/base-drafts <reply+0166e4ab03391f5e5e036d2bc556a1e8351c8556568d9c4f92cf00000001181096d192a169ce16de7e61@reply.github.com>
To: quicwg/base-drafts <base-drafts@noreply.github.com>
Cc: Subscribed <subscribed@noreply.github.com>
Message-ID: <quicwg/base-drafts/pull/2045/review/178040092@github.com>
In-Reply-To: <quicwg/base-drafts/pull/2045@github.com>
References: <quicwg/base-drafts/pull/2045@github.com>
Subject: Re: [quicwg/base-drafts] Discard Initial keys as soon as possible (#2045)
Mime-Version: 1.0
Content-Type: multipart/alternative; boundary="--==_mimepart_5bf8d4d14ef4f_5bb03fb8b94d45c0116090"; charset="UTF-8"
Content-Transfer-Encoding: 7bit
Precedence: list
X-GitHub-Sender: ekr
X-GitHub-Recipient: quic-issues
X-GitHub-Reason: subscribed
X-Auto-Response-Suppress: All
X-GitHub-Recipient-Address: quic-issues@ietf.org
Archived-At: <https://mailarchive.ietf.org/arch/msg/quic-issues/VHcvlmanNqCmOQGZ7NqS1mHe77k>
X-BeenThere: quic-issues@ietf.org
X-Mailman-Version: 2.1.29
List-Id: Notification list for GitHub issues related to the QUIC WG <quic-issues.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/quic-issues>, <mailto:quic-issues-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/quic-issues/>
List-Post: <mailto:quic-issues@ietf.org>
List-Help: <mailto:quic-issues-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/quic-issues>, <mailto:quic-issues-request@ietf.org?subject=subscribe>
X-List-Received-Date: Sat, 24 Nov 2018 04:34:29 -0000

ekr commented on this pull request.



> @@ -691,6 +692,24 @@ will be marked as lost before this, as they leave a gap in the sequence of
 packet numbers.
 
 
+## Discarding Initial Keys {#discard-initial}
+
+Packets protected with Initial secrets ({{initial-secrets}}) are not
+authenticated, meaning that an attacker could spoof packets with the intent to
+disrupt a connection.  To limit these attacks, Initial packet protection keys
+can be discarded more aggressively than other keys.
+
+The successful use of Handshake packets indicates that no more Initial packets
+need to be exchanged, as these keys can only be produced after receiving all
+CRYPTO frames from Initial packets.  Thus, a client MUST discard Initial keys
+when it first sends a Handshake packet and a server MUST discard Initial keys
+when it first successfully processes a Handshake packet.  Endpoints MUST NOT
+send Initial packets after this point.

Yes, and it's not clear to me it's worth making *this* change to defend against this attack. As I said, I don't recall there being consensus to make this change.

-- 
You are receiving this because you are subscribed to this thread.
Reply to this email directly or view it on GitHub:
https://github.com/quicwg/base-drafts/pull/2045#discussion_r236032170