From nobody Sat Mar 21 12:40:12 2020 Return-Path: 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 D8A2A3A0901 for ; Sat, 21 Mar 2020 12:40:10 -0700 (PDT) X-Virus-Scanned: amavisd-new at amsl.com X-Spam-Flag: NO X-Spam-Score: -3.1 X-Spam-Level: X-Spam-Status: No, score=-3.1 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, HTML_MESSAGE=0.001, MAILING_LIST_MULTI=-1, SPF_HELO_NONE=0.001, 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 2HzYFzoxxNUf for ; Sat, 21 Mar 2020 12:40:05 -0700 (PDT) Received: from out-19.smtp.github.com (out-19.smtp.github.com [192.30.252.202]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 8DD643A0900 for ; Sat, 21 Mar 2020 12:40:00 -0700 (PDT) Date: Sat, 21 Mar 2020 12:39:59 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=github.com; s=pf2014; t=1584819599; bh=E+dtWMlt56R5+CTJl8bOgmuGI28hlfB995OiVQMjKw4=; h=Date:From:Reply-To:To:Cc:In-Reply-To:References:Subject:List-ID: List-Archive:List-Post:List-Unsubscribe:From; b=Vsc8OYqrflRsVsH3mBaDS5OSz9tiUwyNGCJqQrL/z6ktupPu7UneGmPWag3BlmVOv rVawAJdxgWvLVs0PKQ5psSc2xcQ1Tqmjzuz2XnOIQgFbSXH4+9rAfeC6f8inzJoJEX jiVxw2ulXcLTsiMLCBBzn4kf/KieZc7p/96OcSiA= From: ianswett Reply-To: quicwg/base-drafts To: quicwg/base-drafts Cc: Subscribed Message-ID: In-Reply-To: References: Subject: Re: [quicwg/base-drafts] Import HTTP/2 Security Considerations (#3531) Mime-Version: 1.0 Content-Type: multipart/alternative; boundary="--==_mimepart_5e766d8ff45c_53fa3fcaf28cd96027815e"; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: list X-GitHub-Sender: ianswett X-GitHub-Recipient: quic-issues X-GitHub-Reason: subscribed X-Auto-Response-Suppress: All X-GitHub-Recipient-Address: quic-issues@ietf.org Archived-At: X-BeenThere: quic-issues@ietf.org X-Mailman-Version: 2.1.29 List-Id: Notification list for GitHub issues related to the QUIC WG List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 21 Mar 2020 19:40:11 -0000 ----==_mimepart_5e766d8ff45c_53fa3fcaf28cd96027815e Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit ianswett commented on this pull request. > +the origin server in the Cache-Control header field. However, this can cause +issues if a single server hosts more than one tenant. For example, a server +might offer multiple users each a small portion of its URI space. + +Where multiple tenants share space on the same server, that server MUST ensure +that tenants are not able to push representations of resources that they do not +have authority over. Failure to enforce this would allow a tenant to provide a +representation that would be served out of cache, overriding the actual +representation that the authoritative tenant provides. + +Pushed responses for which an origin server is not authoritative (see +{{connection-reuse}}) MUST NOT be used or cached. + +## Denial-of-Service Considerations + +An HTTP/3 connection can demand a greater commitment of resources to operate I'm not sure I know why this would be true, particularly for HTTP/2 vs HTTP/3? > +might be done by setting multiple undefined SETTINGS parameters, unknown frame +types, or unknown stream types. Note, however, that some uses are entirely +legitimate, such as optional-to-understand extensions and padding to increase +resistance to traffic analysis. + +Header compression also offers some opportunities to waste processing resources; +see Section 7 of [QPACK] for more details on potential abuses. + +All these features -- i.e., server push, unknown protocol elements, field +compression -- have legitimate uses. These features become a burden only when +they are used unnecessarily or to excess. + +An endpoint that doesn't monitor this behavior exposes itself to a risk of +denial-of-service attack. Implementations SHOULD track the use of these +features and set limits on their use. An endpoint MAY treat activity that is +suspicious as a connection error ({{errors}}) of type H3_EXCESSIVE_LOAD. It might be worth calling out that this could close valid connections and cause requests to fail? > +All these features -- i.e., server push, unknown protocol elements, field +compression -- have legitimate uses. These features become a burden only when +they are used unnecessarily or to excess. + +An endpoint that doesn't monitor this behavior exposes itself to a risk of +denial-of-service attack. Implementations SHOULD track the use of these +features and set limits on their use. An endpoint MAY treat activity that is +suspicious as a connection error ({{errors}}) of type H3_EXCESSIVE_LOAD. + +### Limits on Field Section Size + +A large field section ({{request-response}}) can cause an implementation to +commit a large amount of state. Header fields that are critical for routing can +appear toward the end of a header field section, which prevents streaming of the +header field section to its ultimate destination. This ordering and other +reasons, such as ensuring cache correctness, mean that an endpoint might need to In my experience, this is quite likely a requirement, not just a might. So I'd be inclined to make this stronger(ie: "likely needs to..." -- 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/3531#pullrequestreview-378944999 ----==_mimepart_5e766d8ff45c_53fa3fcaf28cd96027815e Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: 7bit

@ianswett commented on this pull request.

In draft-ietf-quic-http.md:

> +the origin server in the Cache-Control header field. However, this can cause
+issues if a single server hosts more than one tenant.  For example, a server
+might offer multiple users each a small portion of its URI space.
+
+Where multiple tenants share space on the same server, that server MUST ensure
+that tenants are not able to push representations of resources that they do not
+have authority over.  Failure to enforce this would allow a tenant to provide a
+representation that would be served out of cache, overriding the actual
+representation that the authoritative tenant provides.
+
+Pushed responses for which an origin server is not authoritative (see
+{{connection-reuse}}) MUST NOT be used or cached.
+
+## Denial-of-Service Considerations
+
+An HTTP/3 connection can demand a greater commitment of resources to operate

I'm not sure I know why this would be true, particularly for HTTP/2 vs HTTP/3?

In draft-ietf-quic-http.md:

> +might be done by setting multiple undefined SETTINGS parameters, unknown frame
+types, or unknown stream types.  Note, however, that some uses are entirely
+legitimate, such as optional-to-understand extensions and padding to increase
+resistance to traffic analysis.
+
+Header compression also offers some opportunities to waste processing resources;
+see Section 7 of [QPACK] for more details on potential abuses.
+
+All these features -- i.e., server push, unknown protocol elements, field
+compression -- have legitimate uses.  These features become a burden only when
+they are used unnecessarily or to excess.
+
+An endpoint that doesn't monitor this behavior exposes itself to a risk of
+denial-of-service attack.  Implementations SHOULD track the use of these
+features and set limits on their use.  An endpoint MAY treat activity that is
+suspicious as a connection error ({{errors}}) of type H3_EXCESSIVE_LOAD.

It might be worth calling out that this could close valid connections and cause requests to fail?

In draft-ietf-quic-http.md:

> +All these features -- i.e., server push, unknown protocol elements, field
+compression -- have legitimate uses.  These features become a burden only when
+they are used unnecessarily or to excess.
+
+An endpoint that doesn't monitor this behavior exposes itself to a risk of
+denial-of-service attack.  Implementations SHOULD track the use of these
+features and set limits on their use.  An endpoint MAY treat activity that is
+suspicious as a connection error ({{errors}}) of type H3_EXCESSIVE_LOAD.
+
+### Limits on Field Section Size
+
+A large field section ({{request-response}}) can cause an implementation to
+commit a large amount of state.  Header fields that are critical for routing can
+appear toward the end of a header field section, which prevents streaming of the
+header field section to its ultimate destination.  This ordering and other
+reasons, such as ensuring cache correctness, mean that an endpoint might need to

In my experience, this is quite likely a requirement, not just a might. So I'd be inclined to make this stronger(ie: "likely needs to..."

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