Internet DRAFT - draft-an-fast-address-validation
draft-an-fast-address-validation
QUIC Q. An
Internet-Draft DP. Liu
Intended status: Standards Track YM. Liu
Expires: May 3, 2020 H. Wang
Alibaba Inc.
October 31, 2019
Fast Address Validation
draft-an-fast-address-validation-00
Abstract
This document describes a fast address validation method for QUIC.
Status of This Memo
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This Internet-Draft will expire on May 3, 2020.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Notational Conventions . . . . . . . . . . . . . . . . . . . 2
3. Problem Statement . . . . . . . . . . . . . . . . . . . . . . 2
4. Fast Address Validation During Handshake . . . . . . . . . . 4
5. Security Considerations . . . . . . . . . . . . . . . . . . . 4
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
7. Normative References . . . . . . . . . . . . . . . . . . . . 4
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5
1. Introduction
As described in [I-D.ietf-quic-transport], a token based scheme is
defined to facilitate address validation of a client. The token MUST
be covered by integrity protection against modification or
falsification by clients. The server remembers the value it sends to
clients and validates the token sent back from a client. In its
design, Retry packet is used to deliver the token to a client which
address has not yet been validated. It voids the first transmission
of the Initial packet sent by the client, and triggers a second
Initial packet to be sent with the token. The exchange of token will
cause unnecessary longer connection establishment delay for a client.
In this document, an alternative mechanism is proposed to improve the
efficiency of address validation during handshake. For the first
connection between client and server, eliminate the use of Retry
packet for token delivery, and rely on handshake encryption layer to
prove return routability. In addition, New_Token frame is used by
server, via i.e. the Initial packet, to provide the client with an
address validation token that can be used to validate future
connections.
2. Notational Conventions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].
3. Problem Statement
Address validation is used by QUIC to avoid being used for a traffic
amplification attack. In such an attack, a request is sent to a
server with spoofed source address information that identifies a
victim. If a server generates more or larger packets in response to
that request, the attacker can use the server to send more data
toward the victim than it would be able to send on its own.
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The primary defense against amplification attack is verifying that an
endpoint is able to receive packets at the transport address that it
claims. Address validation is performed both during connection
establishment and during connection migration.
Figure 1 provides an overview of the 0-RTT handshake procedure
jointly with address validation defined in [I-D.ietf-quic-transport].
Each line shows a QUIC packet with the packet type and packet number
shown first, followed by the frames that are typically contained in
those packets. So, for instance the first packet is of type Initial,
with packet number 0, and contains a CRYPTO frame carrying the
ClientHello.
Client Server
Initial[0]: CRYPTO[CH]
0-RTT[0]: STREAM[0, "..."] ->
<- Retry+Token
Initial+Token[1]: CRYPTO[CH]
0-RTT[1]: STREAM[0, "..."] ->
Initial[0]: CRYPTO[SH] ACK[1]
Handshake[0] CRYPTO[EE, FIN]
<- 1-RTT[0]: STREAM[1, "..."] ACK[1]
Initial+Token[2]: ACK[0]
Handshake[0]: CRYPTO[FIN], ACK[0]
1-RTT[2]: STREAM[0, "..."] ACK[0] ->
1-RTT[1]: STREAM[3, "..."], ACK[2]
<- Handshake[1]: ACK[0]
Figure 1: Example of 0-RTT Handshake joint with address validation
Note that, the server acknowledges 0-RTT data at the 1-RTT encryption
level, and the client sends 1-RTT packets in the same packet number
space.
A server might wish to validate the client address before starting
the cryptographic handshake. In [I-D.ietf-quic-transport], a token
is defined to provide address validation prior to completing the
handshake. Upon receiving the client's Initial packet, the server
can request address validation by sending a Retry packet containing a
token. When this token is delivered to the client during connection
establishment with a Retry packet, the Initial packet has to be re-
transmitted from the client including the token. It in turn adds one
more round of packet exchange to 0-RTT handshake.
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4. Fast Address Validation During Handshake
For the first connection between client and server, server can choose
to not use Retry packet for token delivery, but rely on handshake
encryption layer to prove return routability. In addition, New_Token
frame is used by server, via i.e. the Initial packet, to provide the
client with an address validation token that can be used to validate
future connections. A flow showing the use of a Handshake packet
with the token is depicted in Figure 2.
Client Server
Initial[0]: CRYPTO[CH]
0-RTT[0]: STREAM[0, "..."] ->
Initial[0]: CRYPTO[SH] ACK[0]
Handshake[0] CRYPTO[EE, FIN] New_Token
<- 1-RTT[0]: STREAM[1, "..."] ACK[0]
Initial[1]: ACK[0]
Handshake: CRYPTO[FIN], ACK[0]
1-RTT[1]: STREAM[0, "..."] ACK[0] ->
1-RTT[1]: STREAM[3, "..."], ACK[1]
<- Handshake[1]: ACK[0]
Figure 2: Example Handshake with fast address validation
It is the server's decision whether to exchange token in Retry or
just Handshake to validate client address. If server chooses to
accept the cost brought by token exchanging in Handshake, due to that
server needs to start maintaining handshake states it will bring more
enhanced experience in client side.
5. Security Considerations
Adding token field to Handshake packet does not add new security
concerns.
6. IANA Considerations
This document makes no request of IANA.
7. Normative References
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[I-D.ietf-quic-transport]
Iyengar, J. and M. Thomson, "QUIC: A UDP-Based Multiplexed
and Secure Transport", draft-ietf-quic-transport-23 (work
in progress), September 2019.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
Authors' Addresses
Qing An
Alibaba Inc.
Email: anqing.aq@alibaba-inc.com
Dapeng Liu
Alibaba Inc.
Email: max.ldp@alibaba-inc.com
Yanmei Liu
Alibaba Inc.
Email: miaoji.lym@alibaba-inc.com
Hao Wang
Alibaba Inc.
Email: tars.wh@alibaba-inc.com
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