Hi James,
Il 29/03/2022 13:41, Gould, James ha scritto:
Mario,
My feedback is embedded below.
--
JG
*James Gould
*Fellow Engineer
jgo...@verisign.com
<applewebdata://13890C55-AAE8-4BF3-A6CE-B4BA42740803/jgo...@verisign.com>
703-948-3271
12061 Bluemont Way
Reston, VA 20190
Verisign.com <http://verisigninc.com/>
*From: *Mario Loffredo <mario.loffr...@iit.cnr.it>
*Date: *Monday, March 28, 2022 at 6:59 AM
*To: *James Gould <jgo...@verisign.com>, "regext@ietf.org"
<regext@ietf.org>
*Subject: *[EXTERNAL] Re: [regext] Comments to the feedback about
epp-over-http
Hi James,
thanks for ypur quick reply.
Please find my comments below.
Il 25/03/2022 16:45, Gould, James ha scritto:
Mario,
For #4 “Cookie vs. HTTP Connection”, you asked the question “can
you further clarify why we should opt for establishing the cookie
at setup of the connection and how should it be possible? For
example, what kind of request should be used to start the HTTP
connection?”.
I implemented pluggable transports in the Verisign EPP SDK, which
included HTTP, HTTPS, TCP, and TLS. The Verisign EPP SDK does
include a client interface as well as a server stub
implementation, so I was able to see the transports from both
sides. Support for HTTP and HTTPS was removed once we stopped
supporting EPP over HTTP. The cookie is setup at the time of the
HTTP or HTTPS connection. There is no “request” that is used to
start the HTTP connection, just like the case for TCP and TLS. A
network connection is made, which includes the underlying TLS
handshake in the case of HTTPS and TLS and the cookie is setup for
HTTP and HTTPS, and then the EPP application protocol rides on top
of it.
It seems to me a very low-level implementation.
Sorry but I stiil don't understand how cookies are returned. They
should be returned in an HTTP response that doesn't correspond to an
HTTP request. Correct?
JG: HTTP is being defined as a transport for EPP, so it should be
treated as such. The setup and tear-down of the HTTP connection,
includes the setup of the cookies that is used for HTTP session
tracking. When a connection is made to the EPP / HTTPS server, the
TLS connection is first established via the TLS-handshake and the HTTP
session is established via setup of the session cookie (e.g.,
JSESSIONID), which then enables the server to maintain state. State
such as tracking failed login attempts and timeouts (idle / command /
absolute), which will result in a drop in the HTTP session /
connection when the login attempt threshold is exceeded. At the
application layer, a HTTPS connection is treated in the same way as a
TLS connection, where the transport handles the framing and the
connection state, and the application layer returns the EPP Greeting
when the connection is setup and drops the connection with a EPP
logout occurs or other EPP session conditions (e.g., exceeding
timeouts). The HTTP session cookie is returned in all the HTTP
responses. There is absolutely no intermingling of the transport
layer (HTTP) with the application layer (EPP) other than making a
connection available to read and write framed packets and the ability
to close the connection when needed.
If so, it seems to me uncompliant with what is stated in the first
paragraph of Section 2.1 of RFC7230:
HTTP is a stateless request/response protocol that operates by
exchanging messages (Section 3
<https://secure-web.cisco.com/1HLyHB_XdFEjfXQwGFkG0LZSLLnG4WFNvmZ-TNjfY6OfIaLTmL1biILbx72S_U5GmIiJtbpg0x39TJ52od6XvJJ-XGkebzBiEggAwQ42v85iZAXdc75eWbMUFwdy__GSQvGqoc_3jBcXvzaJksIZ9kIaGCObuN4sNz3NQqB4Gsr44Gdw9c4U6nDx9j_3kyp9hk3Za8zxK-CiPfgUAyNLhZ53ksc5Ae9PHvSSpW9kjbB9txLir0tvwL_pUPzDpJS2Y/https%3A%2F%2Fwww.rfc-editor.org%2Frfc%2Frfc7230%23section-3>)
across a reliable transport- or
session-layer "connection" (Section 6
<https://secure-web.cisco.com/1vvJc-KSBR_KweDtRuo-dlLx6E_Z9fnj9TRqKJPKmI-z_MzpIyDJWDzfwvS180O64nU4M_K-HwHtvVlPkTyfnMVQ8I50S_dOCSrwzrW9QXz8ckfa9Yj0UZmgPk4aOBSCgpizCtKhPiufait2c-bik8SwDi5FGriXh2QetIDOP_N5qvkVGUCrJ7Agu0Kz55-5IRTrJpPK2rtdg6AYpfgj-5oaNCOjZ9kZcI233HN_HumLXDVcKmYklOTTqh_7mGPwt/https%3A%2F%2Fwww.rfc-editor.org%2Frfc%2Frfc7230%23section-6>).*An
HTTP "client" is a*
* program that establishes a connection to a server for the purpose of*
* sending one or more HTTP requests.* *An HTTP "server" is a program*
* that accepts connections in order to service HTTP requests by sending*
* HTTP responses.*
JG: I don’t see how using HTTP as a EPP transport would be considered
uncompliant with RFC7230. Below is the flow of using HTTP as an EPP
transport:
1. Establish TCP connection
2. Establish TLS session via TLS-handshake
3. Establish HTTP session via setup of the HTTP session cookie (e.g.,
JSESSIONID)
4. Return EPP Greeting in framed HTTP response with the session
cookie (e.g., JSESSIONID)
5. Support HTTP requests in the form of framed EPP commands that are
returned in HTTP responses in the form of framed EPP responses.
6. EPP session ends that drops the connection (HTTP / TLS / TCP)
[ML] I apologize James but I still don't understand how it would be
possible to return an HTTP response including the EPP Greeting and
establish a session cookie without having previously received an HTTP
request or, to say it better, how it would be possible at the
abstraction level provided by all the libraries and frameworks
supporting HTTP communication on both client and server side.
Being HTTP used as a purely transport (L4) protocol but not as a
request/response (L7) protocol, the implementation wouldn't be
compliant with RFC7230.
The same concept is also repeated in Section 2.1 of RFC 2818 "HTTP over
TLS":
The agent acting as the HTTP client should also act as the TLS
client. It should initiate a connection to the server on the
appropriate port and then send the TLS ClientHello to begin the TLS
handshake.*When the TLS handshake has finished. The client may then initiate the
first HTTP request.* All HTTP data MUST be sent as TLS
"application data". Normal HTTP behavior, including retained
connections should be followed.
1.
Anyway, the approach normally followed by every HTTP implementer
leverages the services provided by an application server that
incorporates an HTTP server.
You don't need to manage HTTP connections, HTTP resquest/response
marhsalling/unmarshalling and other low-level details. You just need
to focus on the core of your server.
Similarly, on the other side side, after having configured an HTTP
client instance, a client simply builds and sends an HTTP request,
and then receives and processes an HTTP response.
JG: An EPP client or server should be capable of reusing all the same
command and response processing without dealing with transport
specific logic. The transport layer can be built as a layer that is
pluggable. A client can configure the transport to use on a
per-server basis, and the server can reuse the same command processing
logic whether running on top of TLS or HTTPS, since TLS and HTTPS are
purely transports.
[ML] It's unclear to me how two communications working at different
layers could be handled in the same way. As I wrote in my previous reply
to Matthias, the approach proposed aims to preserve EPP commands
semantics so that the EPP server core should be the same regardless the
fact that it is supported by HTTP or TCP.
Mario
If there is a HTTP transport for EPP, then it should be purely a
transport and not intermingle with the application protocol.
There is no need to directly tie a HTTP session with the
established EPP session. By keeping them separate, it makes it
much easier for the client and the server to have pluggable
transports, where the processing of the EPP commands including the
hello, login, and logout treat the transport as simply a
connection with no intermingling of session management.
If it means that you have to reimplement what has commonly been used
for years, it isn't clear to me how it could be much easier. On the
contrary, it seems to me much trickier, especially if you implement
EPP-over-HTTP from scratch.
If the goal is using the same approach for mapping every transport
layer without considering the peculiarites of each transport protocol
and the technology the implementers are accostumed to use to deal with
them, it doesn't make sense to me.
For example, I cannot figure out how HTTP load balancing could support
your solution.
JG: The HTTP transport for EPP can easily be defined as a pure
transport, which provides a connection for the application layer to
leverage in the same fashion as TLS. The load balancer can leverage
the TLS session id to route to the EPP gateway and in the case of
HTTP, the HTTP session can be used to route the request to the
appropriate application server that contains the connection state.
Some HTTP application server proxies leverage the HTTP session to
route the requests to the application server that contains the HTTP
session and state. You need to establish the HTTP session when the
connection is established to support the needed routing. There are
other load balancing options, but by simplifying EPP over HTTP to have
HTTP as purely a transport, it provides maximum flexibility in routing
and maximum pluggability of transports (TCP, TLS, HTTP, HTTPS).
Best,
Mario
--
JG
*James Gould
*Fellow Engineer
jgo...@verisign.com
<applewebdata://13890C55-AAE8-4BF3-A6CE-B4BA42740803/jgo...@verisign.com>
703-948-3271
12061 Bluemont Way
Reston, VA 20190
Verisign.com
<http://secure-web.cisco.com/1ojxKstUEceETR7pe4khQ2dcwgGUwoOuZu4vhcT-TZcTCCpM93jXl6eq5i46tfTPt6lE9M6FO7hPqFZQVgxN5su1ozpEIXrOmp6SzB5kEB5SXCcRaJIg-vRb2B_SxGeDcgjxTqmZNEVO_Z0LtwZEFTLbzsLhmMMT-MlZ9pX7rpBY6Q8K0RxXyklhUEXCOqlJ0RMcZX2tEZNHp0Pr6XFhgw4X7OA0XCs0tk_jqiJbYMrkAFF0PXiAItfCmm_MR8whC/http%3A%2F%2Fverisigninc.com%2F>
*From: *regext <regext-boun...@ietf.org>
<mailto:regext-boun...@ietf.org> on behalf of Mario Loffredo
<mario.loffr...@iit.cnr.it> <mailto:mario.loffr...@iit.cnr.it>
*Date: *Friday, March 25, 2022 at 11:01 AM
*To: *"regext@ietf.org" <mailto:regext@ietf.org> <regext@ietf.org>
<mailto:regext@ietf.org>
*Subject: *[EXTERNAL] [regext] Comments to the feedback about
epp-over-http
Hi folks,
here are in the following some comments grouped by subject to last
meeting's feedback about EPP-over-HTTP:
*1) Draft title*
Ulrich suggested to call the document EPP-over-HTTPS.
I replied that the name was assigned to be consistent with
RFC5734, i.e. EPP-over-TCP.
SImilarly to RFC5734, the draft states, first in the abstract and
then in the security considerations, that TLS is required.
That being said, the authors don't object to renaming the
dcocument EPP-over-HTTPS if the WG agrees.
*2) Cookies*
Jim (Reed) asked why cookies should be used in this case.
The reasons why we have used session cookiea are that they
represent a standard method (RFC6265), well known to the community
of REST service implementers, largely used and natively supported
by libraries and frameworks on both client and server side. For
example, it is the same method used by rdap-openid to map an RDAP
session and tie it to an access token :-)
.it and .pl have been using this method since the beginning and
the registrars, after being informed that they had to enable
cookies in their HTTP clients, have no longer complained about
cookie management.
In addition, the implementation of such a method doesn't
introduce any change to the EPP core spec. Indeed, it preserves
EPP comands semantics and doesn't mix the application layer with
the transport layer.
I would like to say that, regarding the clear distinction between
those layers, this proposal is even better than RFC5734 as every
EPP response is returned by the server as a consequence of
receiving an EPP request.
On the contrary, in RFC5734, an EPP <greeting> is returned to the
client after the TCP connection has been established so, at least
in this case, the**two layers get mixed.
Which method other than session cookie shoud be used instead ?
*3) Security Considerations*
Ulirch recommended to review the security considerations by
inheriting those from TLS WG about which versions and ciphers of
TLS to use.
Thanks a lot for the heads up, Ulrich. Surely, we'll do.
Gavin noted that, unlike EPP-over-TCP, this draft states that
client IP address check is optional.
As a matter of fact, it is stated as recommended.
Anyway, the authors don't object to changing it into an absolute
rquirement if the WG agrees.
*4) Cookie vs. HTTP Connection*
One comment from James in the chat is about establishing the
cookie at setup of the connection and not linking it to the EPP
Login command.
James, can you further clarify why we should opt for establishing
the cookie at setup of the connection and how shoudl it be
possible? For example, what kind of request should be used to
start the HTTP connection?
IMO, an HTTP session is something that is inherently unlinked to
the HTTP connections.
HTTP connections can be broken but sessions don't get lost.
Programmatically, REST implementers are in charge of processing
HTTP requests and building responses rather than managing HTTP
connections, which is instead delegated to the application servers.
Finally, I would like to outline that Section 2.9.1 of RFC5730
states that an EPP session starts with a Login command and the
mechanism described by RFC6265 lets (I'm quoting here) "the
servers maintain a stateful session over the mostly stateless HTTP
protocol". As a consequence, it seems much more practical to start
the EPP/HTTP session as a result of a Login command.
*5) EPP/HTTP Sessions vs. HTTP3 Connections*
Ulrich remarked that, in HTTP3, it is possible to have multiple
sessions on an HTTP connection.
This is valid also for the other HTTP versions.
In fact, an HTTP connection can be kept alive and, over it, a
client could submit multiple login-commands-logout sequences.
This is quite usual for a smart client managing a pool of HTTP
connections.
Instead, It is unlikely but not impossible to come across HTTP
connections supporting multiple concurrent sessions.
What should be the possible drawbacks for a server in allowing the
scenarios above?
*6) Client authentication in HTTP3*
Another note pointed out that HTTP3 client authentication
requirements are different from this draft and they need to be
reconciled.
Think that it could be sufficient to add to the security
considerations some text similar to what is included in section
4.4 "Peer authentication" of RFC 9001 "Using TLS to secure QUIC":
A client MUST authenticate the identity of the server. This
typically involves verification that the identity of the server is
included in a certificate and that the certificate is issued by a
trusted entity (see for example [RFC2818
<https://secure-web.cisco.com/1tkPqD6aAMfTp6t6KppHDGdn0xpgOWSMeCqwZR-hs9Duph9SiceA0vCbaJJVqywNzcZscc6vUZkCPH9lCdtXq_nVJ3OfnNMz-XTQvhBuSBLsXa0VfO5ZNrGo47fSin8GRaQOWRSvSQP_7vRecBdddhF6L0Yqx3KcxAGpvdxpFCsPhLcd5bm-aVy3vTko6TfGBlohe2XEw3bwUmH-u56ZuZz50CUXUqA3YDFgBENAwPrLBjwdDxwgG1JFVGPZF_LEQ/https%3A%2F%2Fdatatracker.ietf.org%2Fdoc%2Fhtml%2Frfc2818>]).
The draft has only considered the optional use of a certificate on
server side (not on client side). In doing that, the draft is
consistent with another sentence in the same paragraph of RFC9001:
A server MAY request that the client authenticate during the
handshake. A server MAY refuse a connection if the client is unable
to authenticate when requested.
Would it address the feedback?
That's all for now.
Hope I did not miss anything.
Thanks a lot for your interest and feedback.
Looking forward to your further comments.
Best,
Mario
--
Dr. Mario Loffredo
Technological Unit “Digital Innovation”
Institute of Informatics and Telematics (IIT)
National Research Council (CNR)
via G. Moruzzi 1, I-56124 PISA, Italy
Phone: +39.0503153497
Web:http://www.iit.cnr.it/mario.loffredo
<http://secure-web.cisco.com/1Af0lIvD4wj2TkngfEVwrFVEVRozLiVIU2m1Gi1AH1GN4-eWP-IREXsOLCh8OJ03YAxRNYqVCPHQSwgj-tMCyzvN3jokOBTIBx4-5n1pJdiRXxl-ShJCaHkCjGNPa8EA5qw4kPjkxIrFAy1qOTcPFhieqdc_xyu8yisYoXzily9ozVw3GZaUtkKrLnmnDJhlFv2LRTCTnw913LzH8bX-hB6FpPlyFi_0v2_H1NFCgZYjuu4pgUeOeIqQJRQwtzNLS/http%3A%2F%2Fwww.iit.cnr.it%2Fmario.loffredo>
--
Dr. Mario Loffredo
Technological Unit “Digital Innovation”
Institute of Informatics and Telematics (IIT)
National Research Council (CNR)
via G. Moruzzi 1, I-56124 PISA, Italy
Phone: +39.0503153497
Web:http://www.iit.cnr.it/mario.loffredo
<http://secure-web.cisco.com/1OpUT5efcRPCKu9ZmpfyFmbeoIexTqMIlduFKl7VTUSeET1W3oogufCAfJPPw-WSQ0iyo_wkztY_7M69qw0yf13C4w7OWB_Zk5w2FsV-GGCSLot8lFQdslU0DvCpCTw9FjZr0AsFsubGH-kToYrLxzzEj7vGDKuxIFxPK92P5bu2CDOE4UFtRPRGvu9rzX83rks8X2le_j1uSS1SD5B8CyvSp0tsne0HWMS5luho_DIhdOil7-0a_7ZX6CQA08GQq/http%3A%2F%2Fwww.iit.cnr.it%2Fmario.loffredo>
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--
Dr. Mario Loffredo
Technological Unit “Digital Innovation”
Institute of Informatics and Telematics (IIT)
National Research Council (CNR)
via G. Moruzzi 1, I-56124 PISA, Italy
Phone: +39.0503153497
Web:http://www.iit.cnr.it/mario.loffredo
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