Merge branch 'feature/xep-0389'

This commit is contained in:
Jonas Schäfer 2020-05-26 17:25:49 +02:00
commit 8e5fd8100e
1 changed files with 228 additions and 106 deletions

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@ -31,6 +31,19 @@
<supersededby/>
<shortname>ibr2</shortname>
&sam;
<revision>
<version>0.5.0</version>
<date>2020-05-26</date>
<initials>ssw</initials>
<remark>
<ul>
<li>Overhaul document for readability.</li>
<li>Add JID and username information to success element.</li>
<li>Always require disco/caps feature.</li>
<li>More examples.</li>
</ul>
</remark>
</revision>
<revision>
<version>0.4.0</version>
<date>2020-04-22</date>
@ -196,18 +209,43 @@
</ul>
</section1>
<section1 topic='Discovering Support' anchor='disco'>
<p>
Clients, servers, and other services such as components that support
Extensible IBR MUST advertise the fact by including a feature of
"urn::xmpp:register:0" in response to &xep0030; information requests and in
their &xep0115; profiles.
</p>
<example caption='Disco info response'><![CDATA[
<query xmlns='http://jabber.org/protocol/disco#info'>
<feature var='urn:xmpp:register:0' />
</query>]]></example>
</section1>
<section1 topic='Flows' anchor='flows'>
<p>
Registration or recovery is completed after responding to a series of
challenges issued by the server.
Challenges are grouped in to "flows", a number of challenges that may be
issued together to complete an action.
For example, a registration flow might be created that issues a data form
challenge which will be shown to the user to gather information, then issues
a second data form challenge to let the user enter a confirmation code that
was sent to their email.
</p>
<section2 topic='Stream Feature'>
<p>
If a server supports registering for or recovering an account using
Extensible IBR, it MUST inform the connecting client when returning stream
features during the stream negotiation process.
Extensible IBR during stream negotiation, it MUST inform the connecting
client when returning stream features during the stream negotiation process.
This is done by including a &lt;register/&gt; element, qualified by the
'urn:xmpp:register:0' namespace for account registration, or a
&lt;recovery/&gt; element qualified by the same namespace for account
recovery.
The register and recovery features are always voluntary-to-negotiate.
The registration and recovery features MUST NOT be advertised before
encryption has been negotiated, eg. using direct TLS or opportunistic TLS.
The registration and recovery features MUST NOT be advertised before a
security layer has been negotiated, eg. using direct TLS or opportunistic
TLS.
They SHOULD be advertised at the same time as the SASL authentication
feature, meaning that after registration or recovery is completed SASL
authentication can proceed.
@ -220,15 +258,17 @@
workflow that only contains challenges which the client supports.
Each &lt;flow/&gt; element MUST have a unique "id" attribute which is used
by the client to identify the flow being selected.
They must also have at least one &lt;name/&gt; element containing a short,
The id attribute is only used during this particular flow negotiation and
has no meaning after a flow has been selected.
Flows must also have at least one &lt;name/&gt; element containing a short,
human readable description of the flow.
If multiple &lt;name/&gt; elements are present they MUST have unique values
for the "xml:lang" attribute.
Clients MAY use the name element to show the different flows to the user and
ask them to pick between them.
Each flow must also contain an unordered set of &lt;challenge/&gt; elements
representing the various challenges that must be completed to complete the
registration or recovery flow.
Each flow element must also contain an unordered set of &lt;challenge/&gt;
elements representing the various challenge types that may be required to
complete the registration or recovery flow.
Each &lt;challenge/&gt; element contains a "type" attribute that uniquely
identifies the challenge for the purpose of determining if it is supported.
If a flow would offer the same challenge twice (eg. two data forms asking
@ -272,40 +312,35 @@
</recovery>
</stream:features>]]></example>
</section2>
<section2 topic='Service Discovery'>
<p>
Clients, servers, and other services such as components that support
Extensible IBR after stream negotiation is complete MUST advertise the
fact by including a feature of "urn::xmpp:register:0" in response to
&xep0030; information requests and in their &xep0115; profiles.
</p>
<example caption='Disco info response'><![CDATA[
<query xmlns='http://jabber.org/protocol/disco#info'>
<feature var='urn:xmpp:register:0' />
</query>]]></example>
</section2>
<p>
Just because a challenge type is listed by the server in the initial flow
element does not mean that it will be issued by the server.
Servers MAY choose to issue more or fewer challenges based on the result of
previous challenges and may not use every challenge type listed in the
original flow.
</p>
<section2 topic='Retrieving the Flows'>
<p>
Registration or recovery may also be completed after stream neogtiation if
server policy allows it.
</p>
<p>
To find what flows an entity provides (if any) after stream negotiation is
complete the requester can send an IQ of type "get" containing a
&lt;register&gt; or &lt;recovery&gt; element qualified by the
"urn:xmpp:register:0" namespace.
</p>
<p>
When responding to a query for registration or recovery flows the list of
challenges should be included just as it would be if during stream feature
negotiation.
That is, a "register" or "recovery" element containing a list of flows,
each with an id, containing a name and a list of challenges.
If an entity supports this specification but does not provide any flows
after stream negotiation it MUST respond with an empty list.
</p>
<example caption='Registration flows query'><![CDATA[
<iq type='get'>
<register xmlns='urn:xmpp:register:0'/>
</iq>]]></example>
<p>
When responding to a query for registration or recovery flows the list of
challenges MUST be included just as it would be during stream feature
negotiation.
That is, a "register" or "recovery" element containing a list of flows,
each with an id, containing a name and a list of challenges.
</p>
<example caption='Registration flows results'><![CDATA[
<iq type='result'>
<register xmlns='urn:xmpp:register:0'>
@ -324,64 +359,141 @@
</flow>
</register>
</iq>]]></example>
<p>
If an entity supports issuing challenges but does not provide any flows
after stream negotiation is complete it MUST respond with an empty list.
Similarly, an entity that supports this specification but does not support
issuign challenges itself (for example, a client that only supports
receiving challenges) it MUST respond successfully with an empty list.
</p>
<example caption='Empty registration flows results'><![CDATA[
<iq type='result'>
<register xmlns='urn:xmpp:register:0'/>
</iq>]]></example>
</section2>
</section1>
<section1 topic='Challenges' anchor='challenge'>
<p>
A client selects the registration or recovery feature for negotiation by
replying with an element of the same name and namespace.
The element MUST contain a &lt;flow&gt; element that MUST have an "id"
attribute matching one of the flows advertised by the server.
For example, to select the "Verify by Phone Call" registration flow from
the previous example, the client would reply with:
</p>
<section2 topic='Issuing Challenges' anchor='challenge'>
<p>
A client selects the registration or recovery feature for negotiation by
replying with an element of the same name and namespace.
The element MUST contain a &lt;flow&gt; element that MUST have an "id"
attribute matching one of the flows advertised by the server.
For example, to select the "Verify by Phone Call" registration flow from
the previous example, the client would reply with:
</p>
<example caption='Client selects a recovery flow'><![CDATA[
<register xmlns='urn:xmpp:register:0'>
<flow id='1'/>
</register>]]></example>
<p>
If the client is initiating registration or recovery after a stream has
already been initiated it uses the same registration element wrapped in an
IQ of type "set".
<p>
If the client is initiating registration or recovery after a stream has
already been initiated it uses the same registration element wrapped in an
IQ of type "set".
</p>
<example caption='Client selects a recovery flow after stream negotiation'><![CDATA[
<example caption='Client selects a recovery flow after stream negotiation'><![CDATA[
<iq type='set' id='foo'>
<recovery xmlns='urn:xmpp:register:0'>
<flow id='0'/>
</recovery>
</iq>]]></example>
<p>
The server then replies to the IQ or feature selection with a challenge.
If replying to an IQ, the challenge must be wrapped in an IQ of type
"result".
Challenges take the form of a &lt;challenge/&gt; element qualified by the
'urn:xmpp:register:0' namespace with a 'type' attribute that uniquely
identifies the type of payload a client might expect the element to contain.
</p>
<p>
The server then replies to the IQ or feature selection with a challenge.
If replying to an IQ, the challenge must be wrapped in an IQ of type
"result".
Challenges take the form of a &lt;challenge/&gt; element qualified by the
'urn:xmpp:register:0' namespace with a 'type' attribute that uniquely
identifies the type of payload a client might expect the element to
contain.
</p>
<example caption='Server issues a challenge'><![CDATA[
<challenge xmlns='urn:xmpp:register:0'
type='urn:example:challenge'>
<example xmlns='urn:example:challenge'>Payload</example>
</challenge>]]></example>
<p>
After a challenge is received, the client replies to the challenge by
sending a &lt;response/&gt; element qualified by the 'urn:xmpp:register:0'
namespace or a cancellation as defined later in this document.
If the client sends a response, it MUST also include the payload
corresponding to the challenges 'type' element (which may be empty).
</p>
<p>
After a challenge is received, the client replies to the challenge by
sending a &lt;response/&gt; element qualified by the 'urn:xmpp:register:0'
namespace or a cancellation as defined later in this document.
If the client sends a response, it MUST also include the payload
corresponding to the challenges 'type' element (which may be empty).
</p>
<example caption='Client responds to a challenge'><![CDATA[
<response xmlns='urn:xmpp:register:0'>
<result xmlns='urn:example:challenge'>Example Response</result>
</response>]]></example>
<p>
After a response is received, if the server needs more information it MAY
issue another challenge.
For example, if the user has entered their email in response to a
challenge, the server might send an email and then issue another challenge
asking for the unique code sent in the email.
</p>
</section2>
<section2 topic='Completing Registration or Recovery' anchor='completion'>
<p>
If after receiving a challenge or response a client or server does not
wish to continue registration or recovery, it may send an empty
&lt;cancel/&gt; element qualified by the 'urn:xmpp:register:0' namespace.
This informs the client or server that registration is complete.
This is the same as submitting a data form of type 'cancel' in response to
a data form challenge.
</p>
<example caption='User Cancels Registration or Recovery'><![CDATA[
<cancel xmlns='urn:xmpp:register:0'/>]]></example>
<p>
If the IQ based registration or recovery flow is being used and the server
wishes to cancel the flow, it MAY respond to any IQ with the cancel
element and type "result".
</p>
<example caption='Client or server cancels request'><![CDATA[
<iq type='result' id='bar'>
<cancel xmlns='urn:xmpp:register:0'/>
</iq>]]></example>
<p>
A server may also issue a cancelation IQ with type 'set' if it wishes to
cancel after a request/response has been received (ie. when there is no
existing IQ to respond to).
</p>
<example caption='Server cancels flow'><![CDATA[
<iq type='set' id='bar'>
<cancel xmlns='urn:xmpp:register:0'/>
</iq>]]></example>
<p>
If the client successfully completes all required challenges during stream
negotiation the server MUST return a &lt;success/&gt; element qualified by
the 'urn:xmpp:register:0' namespace, at which point it may continue with
the stream negotiation process.
The success element MUST contain a &lt;jid&gt; element containing the bare
JID as registered or recovered by the server and a &lt;username&gt;
element containing the simple user name for use with SASL (normally this
will be the same as the localpart of the JID).
</p>
<example caption='Server indicates success during steam negotiation'><![CDATA[
<success xmlns='urn:xmpp:register:0'>
<jid>mercutio@example.net</jid>
<username>mercutio</username>
</success>]]></example>
<p>
If the IQ based flow is being used and the server wishes to indicate
success after a challenge has been completed it sends an IQ of type "set"
containing the &lt;success/&gt; element.
</p>
<example caption='Server indicates success after stream negotiation'><![CDATA[
<iq type='set' id='bar'>
<success xmlns='urn:xmpp:register:0'>
<jid>mercutio@example.net</jid>
<username>mercutio</username>
</success>
</iq>]]></example>
</section2>
</section1>
<section1 topic='Challenges' anchor='challenge'>
<p>
This document defines several challenges that use existing technologies.
</p>
<section2 topic='Data Form' anchor='dataform'>
<p>
This document defines a type of 'jabber:x:data' which MUST always contain a
data form (an 'x' element with type 'form') as defined by &xep0004;.
Challenges of type 'jabber:x:data' MUST always contain a data form (an 'x'
element with type 'form') as defined by &xep0004;.
</p>
<example caption='Server issues a data form challenge'><![CDATA[
<challenge xmlns='urn:xmpp:register:0'
@ -434,7 +546,7 @@
</section2>
<section2 topic='Out of Band Data' anchor='oob'>
<p>
Challenges of the type "jabber:x:oob" MUST contain an &lt;x/&gt; element
Challenges of type "jabber:x:oob" MUST contain an &lt;x/&gt; element
qualified by the "jabber:x:oob" namespace as defined in &xep0066;.
</p>
<example caption='Server issues an OOB challenge'><![CDATA[
@ -450,44 +562,54 @@
<example caption='Client acknowledges the OOB challenge'><![CDATA[
<response xmlns='urn:xmpp:register:0'/>]]></example>
</section2>
</section1>
<section1 topic='Completing Registration or Recovery' anchor='completion'>
<p>
If after receiving a challenge or response a client or server does not wish
to continue registration or recovery, it may send an empty &lt;cancel/&gt;
element qualified by the 'urn:xmpp:register:0' namespace.
This informs the client or server that registration is complete.
This is the same as submitting a data form of type 'cancel' in response to a
data form challenge.
</p>
<example caption='User Cancels Registration or Recovery'><![CDATA[
<cancel xmlns='urn:xmpp:register:0'/>]]></example>
<p>
If the IQ based registration or recovery flow is being used and the server
wishes to cancel the flow, it MAY respond to any IQ from the client with the
cancel element and type "result".
</p>
<example caption='Server cancels request'><![CDATA[
<iq type='result' id='bar'>
<cancel xmlns='urn:xmpp:register:0'/>
</iq>]]></example>
<p>
If the client successfully completes all required challenges during stream
negotiation the server MUST return an empty &lt;success/&gt; element
qualified by the 'urn:xmpp:register:0' namespace, at which point it may
continue with the stream negotiation process.
If the server needs more information, for example, in the previous challenge
the user entered an email and now the server wishes to ask for a code that
was sent to that email, the server MAY send another challenge.
</p>
<example caption='Server indicates success during steam negotiation'><![CDATA[
<success xmlns='urn:xmpp:register:0'/>]]></example>
<p>
If the IQ based flow is being used and the server wishes to indicate success
it sends an empty IQ response of type "result".
</p>
<example caption='Server indicates success after stream negotiation'><![CDATA[
<iq type='result' id='bar' />]]></example>
<section2 topic='SASL' anchor='sasl'>
<p>
Servers can support changing passwords by providing a reset flow
containing a SASL challenge.
The SASL challenge re-uses the SASL profile from &rfc6120;.
The server begins by sending the mechanisms list, and the client responds
by selecting a mechanism and possibly including initial data.
Each step in the SASL process is issued as a new SASL challenge.
</p>
<example caption='SASL challenge flow'><![CDATA[
<!-- Server -->
<challenge xmlns='urn:xmpp:register:0'
type='urn:ietf:params:xml:ns:xmpp-sasl'>
<mechanisms xmlns='urn:ietf:params:xml:ns:xmpp-sasl'>
<mechanism>EXTERNAL</mechanism>
<mechanism>SCRAM-SHA-1-PLUS</mechanism>
<mechanism>SCRAM-SHA-1</mechanism>
<mechanism>PLAIN</mechanism>
</mechanisms>
</challenge>
<!-- Client -->
<response xmlns='urn:xmpp:register:0'>
<auth xmlns="urn:ietf:params:xml:ns:xmpp-sasl"
mechanism="SCRAM-SHA-1">
biwsbj1qdWxpZXQscj1vTXNUQUF3QUFBQU1BQUFBTlAwVEFBQUFBQUJQVTBBQQ==
</auth>
</response>
<!-- Server -->
<challenge xmlns='urn:xmpp:register:0'
type='urn:ietf:params:xml:ns:xmpp-sasl'>
<challenge xmlns="urn:ietf:params:xml:ns:xmpp-sasl">
cj1vTXNUQUF3QUFBQU1BQUFBTlAwVEFBQUFBQUJQVTBBQWUxMjQ2OTViLTY5Y
TktNGRlNi05YzMwLWI1MWIzODA4YzU5ZSxzPU5qaGtZVE0wTURndE5HWTBaaT
AwTmpkbUxUa3hNbVV0TkRsbU5UTm1ORE5rTURNeixpPTQwOTY=
</challenge>
</challenge>
<!-- Client -->
<response xmlns='urn:xmpp:register:0'>
<response xmlns="urn:ietf:params:xml:ns:xmpp-sasl">
Yz1iaXdzLHI9b01zVEFBd0FBQUFNQUFBQU5QMFRBQUFBQUFCUFUwQUFlMTI0N
jk1Yi02OWE5LTRkZTYtOWMzMC1iNTFiMzgwOGM1OWUscD1VQTU3dE0vU3ZwQV
RCa0gyRlhzMFdEWHZKWXc9
</response>
</response>]]></example>
</section2>
</section1>
<section1 topic='Internationalization Considerations' anchor='i18n'>
<p>
@ -506,10 +628,10 @@
Servers that allow in-band registration need to take measures to prevent
abuse.
Common techniques to prevent spam registrations include displaying CAPTCHAs
or requiring proof-of-possession of a valid email address or telephone number
by sending a unique code (e.g. an HMAC that can later be verified as having
originated at the server) to the users email and requiring that they enter
the code before continuing.
or requiring proof-of-possession of a valid email address or telephone
number by sending a unique code (e.g. an HMAC that can later be verified as
having originated at the server) to the users email and requiring that they
enter the code before continuing.
Servers that do not take such measures risk being black listed by other
servers in the network.
</p>