Last Call Review of draft-hollenbeck-rfc4933bis-
I have reviewed this document as part of the security directorate's
ongoing effort to review all IETF documents being processed by the IESG.
These comments were written primarily for the benefit of the security area
directors. Document editors and WG chairs should treat these comments
just like any other last call comments.
The draft updates RFC 4933, the EPP Contacts Mapping spec. The updates
listed are relatively minor - updates to references and a few minor
updates to text.
Many of my comments below apply to language that was in RFC4933, but
perhaps it is OK to suggest changes from the original at this point.
First: EPP, as in RFC4930 and draft *-rfc4930bis-01*, employs a very
simple authentication scheme that is cleartext password based.
It therefore mandates:
Specifically, EPP instances MUST be protected using
a transport mechanism or application protocol that provides
integrity, confidentiality, and mutual strong client-server
This mandate is inherited by the rfc4933bis draft, which also says
Both client and server MUST ensure that authorization
information is stored and exchanged with high-grade encryption
mechanisms to provide privacy services.
I would expect that this would make the protocol subject to channel
binding issues. I probably am not up on the whole idea, but the I
reviewed RFC5060 and the description of the problem sure sounds like it
applies to EPP as well.
OTOH, I seem to recall several drafts recently that relied on the security
of their transport layers, and no one has been talking about how they deal
with channel binding. Maybe I'm way off.
Also, the security considerations there and in rfc4930bis do not address
the cases when completion of a pending request is communicated by an
out-of-band mechanism. I don't know if there are security concerns for
those notifications, but given that they are not covered by the security
of the transport mechanism, advice would be good.
sect 2.2, page 5
- pendingCreate, pendingDelete, pendingRenew, pendingTransfer,
A transform command has been processed for the object, but the
action has not been completed by the server. Server operators can
delay action completion for a variety of reasons, such as to allow
for human review or third-party action. A transform command that
is processed, but whose requested action is pending, is noted with
response code 1001.
When the requested action has been completed, the pendingCreate,
pendingDelete, pendingTransfer, or pendingUpdate status value MUST be
Later, sect 3.3 page 27 says (indirectly) that the status MUST be set if
the action is delayed:
The status of the corresponding object MUST clearly reflect
processing of the pending action.
If the MUST for removal is here, it would be good to be consistent and put
the MUST for setting the status as well. (As a matter of fact, it would
be nice to mention the pending<action> status being set in the description
of the transform commands as well.)
(By the way: why is a pendingRenew status defined when section 3.2 says
there is no mapping defined for the Renew command?)
Same section, immediately following:
All clients involved in the transaction MUST be notified
using a service message that the action has been completed and that
the status of the object has changed.
Later sections (p 17 sec 3.2 and p 28 sec 3.3) add qualifications to this
MUST: "Other notification methods MAY be used" and "or by using an
sect 2.9, page 7
A server operator MUST reject any
transaction that requests disclosure practices that do not conform to
the announced data collection policy with a 2308 error response code.
When servers are compling with client specified exceptional disclosure
handling for some data elements, does this same requirement apply, and
with the same error code?
sect 3.1.2, page 14
The <info> response example contains:
S: <contact:voice x="1234">+1.7035555555</contact:voice>
S: <contact:disclose flag="0">
Section 2.9, page 7 says
In conjunction with this disclosure
requirement, this mapping includes data elements that allow a client
to identify elements that require exceptional server operator
handling to allow or restrict disclosure to third parties.
but then also
A value of "false" or "0" (zero)
notes a client preference to not allow disclosure of the specified
elements as an exception to the stated data collection policy.
Between "require .. operator handling" and "client preference", I'm not
sure of the obligation the server has to refrain from disclosing data
elements that the client has requested be prohibited from disclosing
But at any rate, this example seems to me to be ignoring the client's
request. True? If so, and allowed, it would deserve more discussion.
sect 3.2, page 17
Server operators SHOULD confirm that a client is authorized to
perform a transform command on a given object. Any attempt to
transform an object by an unauthorized client MUST be rejected, and
the server MUST return a 2201 response code to the client to note
that the client lacks privileges to execute the requested command.
Is that "MUST be rejected" only in the case that the server operator
decides that they will confirm authorization?
sect 3.2.2, page 20
A contact object SHOULD NOT be deleted if it is associated with other
known objects. An associated contact SHOULD NOT be deleted until
associations with other known objects have been broken. A server
SHOULD notify clients that object relationships exist by sending a
2305 error response code when a <delete> command is attempted and
fails due to existing object relationships.
Do these object associations and object relationships include cases where
the status is "clientDeleteProhibited" or "serverDeleteProhibited"? If
not, should there be this (or some other) error message in those status
cases as well? The prohibition status values don't seem to show up in the
discussions of server response to commands. Perhaps those prohibitions
are covered under the "An EPP error response MUST be returned if the ...
command cannot be processed for any reason". I believe an explicit
discussion would be good, including the appropriate error code. (Same
comment in the Transfer and Update commands.)
sect 3.2.5, page 24
At least one <contact:add>, <contact:rem>, or <contact:chg> element
MUST be provided if the command is not being extended. All of these
elements MAY be omitted if an <update> extension is present. The
<contact:add> and <contact:rem> elements contain the following child
- One or more <contact:status> elements that contain status values
to be associated with or removed from the object. When specifying
a value to be removed, only the attribute value is significant;
element text is not required to match a value for removal.
Who is responsible for ensuring the valid status combinations discussed in
sect 2.2? I.e., if the client is adding a prohibition, does the server
remove the "ok" status or must the client include that removal in the
update? if the removal is in the same update, does the order in the
update matter (removal first?)?
Note: the example adds a prohibition without removing an "ok" status,
implying that the client is not responsible. But it is not necessarily
the case that the "ok" status was there, so the implication isn't certain.
sect 3.3, page 27
The server MUST also notify the
client when offline processing of the action has been completed.
Object mappings SHOULD describe standard formats for notices that
describe completion of offline processing.
Section 3.3 contains an example of the contents of the notification for a
create command. But Delete, Update and Transfer may also be pending.
Should there be a description of their notification service messages also?