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Merge pull request #1418 from dmcgowan/oauth-spec

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Add specification for using OAuth with the token server
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Aaron Lehmann 2016-03-31 10:42:12 -07:00
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docs/spec/auth/index.md
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@ -8,5 +8,7 @@ keywords = ["registry, on-prem, images, tags, repository, distribution, authenti
# Docker Registry v2 authentication
See the [Token Authentication Specification](token.md) and
[Token Authentication Implementation](jwt.md) for more information.
See the [Token Authentication Specification](token.md),
[Token Authentication Implementation](jwt.md),
[Token Scope Documentation](scope.md),
[OAuth2 Token Authentication](oauth.md) for more information.

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<!--[metadata]>
+++
title = "Oauth2 Token Authentication"
description = "Specifies the Docker Registry v2 authentication"
keywords = ["registry, on-prem, images, tags, repository, distribution, oauth2, advanced"]
[menu.main]
parent="smn_registry_ref"
+++
<![end-metadata]-->
# Docker Registry v2 authentication using OAuth2
This document describes support for the OAuth2 protocol within the authorization
server. [RFC6749](https://tools.ietf.org/html/rfc6749) should be used as a
reference for the protocol and HTTP endpoints described here.
## Refresh token format
The format of the refresh token is completely opaque to the client and should be
determined by the authorization server. The authorization should ensure the
token is sufficiently long and is responsible for storing any information about
long-lived tokens which may be needed for revoking. Any information stored
inside the token will not be extracted and presented by clients.
## Getting a token
POST /token
#### Headers
Content-Type: application/x-www-form-urlencoded
#### Post parameters
<dl>
<dt>
<code>grant_type</code>
</dt>
<dd>
(REQUIRED) Type of grant used to get token. When getting a refresh token
using credentials this type should be set to "password" and have the
accompanying username and password paramters. Type "authorization_code"
is reserved for future use for authenticating to an authorization server
without having to send credentials directly from the client. When
requesting an access token with a refresh token this should be set to
"refresh_token".
</dd>
<dt>
<code>service</code>
</dt>
<dd>
(REQUIRED) The name of the service which hosts the resource to get
access for. Refresh tokens will only be good for getting tokens for
this service.
</dd>
<dt>
<code>client_id</code>
</dt>
<dd>
(REQUIRED) String identifying the client. This client_id does not need
to be registered with the authorization server but should be set to a
meaningful value in order to allow auditing keys created by unregistered
clients. Accepted syntax is defined in
[RFC6749 Appendix A.1](https://tools.ietf.org/html/rfc6749#appendix-A.1)
</dd>
<dt>
<code>access_type</code>
</dt>
<dd>
(OPTIONAL) Access which is being requested. If "offline" is provided
then a refresh token will be returned. The default is "online" only
returning short lived access token. If the grant type is "refresh_token"
this will only return the same refresh token and not a new one.
</dd>
<dt>
<code>scope</code>
</dt>
<dd>
(OPTIONAL) The resource in question, formatted as one of the space-delimited
entries from the <code>scope</code> parameters from the <code>WWW-Authenticate</code> header
shown above. This query parameter should only be specified once but may
contain multiple scopes using the scope list format defined in the scope
grammar. If multiple <code>scope</code> is provided from
<code>WWW-Authenticate</code> header the scopes should first be
converted to a scope list before requesting the token. The above example
would be specified as: <code>scope=repository:samalba/my-app:push</code>.
When requesting a refresh token the scopes may be empty since the
refresh token will not be limited by this scope, only the provided short
lived access token will have the scope limitation.
</dd>
<dt>
<code>refresh_token</code>
</dt>
<dd>
(OPTIONAL) The refresh token to use for authentication when grant type "refresh_token" is used.
</dd>
<dt>
<code>username</code>
</dt>
<dd>
(OPTIONAL) The username to use for authentication when grant type "password" is used.
</dd>
<dt>
<code>password</code>
</dt>
<dd>
(OPTIONAL) The password to use for authentication when grant type "password" is used.
</dd>
</dl>
#### Response fields
<dl>
<dt>
<code>access_token</code>
</dt>
<dd>
(REQUIRED) An opaque <code>Bearer</code> token that clients should
supply to subsequent requests in the <code>Authorization</code> header.
This token should not be attempted to be parsed or understood by the
client but treated as opaque string.
</dd>
<dt>
<code>scope</code>
</dt>
<dd>
(REQUIRED) The scope granted inside the access token. This may be the
same scope as requested or a subset. This requirement is stronger than
specified in [RFC6749 Section 4.2.2](https://tools.ietf.org/html/rfc6749#section-4.2.2)
by strictly requiring the scope in the return value.
</dd>
<dt>
<code>expires_in</code>
</dt>
<dd>
(REQUIRED) The duration in seconds since the token was issued that it
will remain valid. When omitted, this defaults to 60 seconds. For
compatibility with older clients, a token should never be returned with
less than 60 seconds to live.
</dd>
<dt>
<code>issued_at</code>
</dt>
<dd>
(Optional) The <a href="https://www.ietf.org/rfc/rfc3339.txt">RFC3339</a>-serialized UTC
standard time at which a given token was issued. If <code>issued_at</code> is omitted, the
expiration is from when the token exchange completed.
</dd>
<dt>
<code>refresh_token</code>
</dt>
<dd>
(Optional) Token which can be used to get additional access tokens for
the same subject with different scopes. This token should be kept secure
by the client and only sent to the authorization server which issues
bearer tokens. This field will only be set when `access_type=offline` is
provided in the request.
</dd>
</dl>
#### Example getting refresh token
```
POST /token HTTP/1.1
Host: auth.docker.io
Content-Type: application/x-www-form-urlencoded
grant_type=password&username=johndoe&password=A3ddj3w&service=hub.docker.io&client_id=dockerengine&access_type=offline
HTTP/1.1 200 OK
Content-Type: application/json
{"refresh_token":"kas9Da81Dfa8","access_token":"eyJhbGciOiJFUzI1NiIsInR5","expires_in":"900","scope":""}
````
#### Example refreshing an Access Token
````
POST /token HTTP/1.1
Host: auth.docker.io
Content-Type: application/x-www-form-urlencoded
grant_type=refresh_token&refresh_token=kas9Da81Dfa8&service=registry-1.docker.io&client_id=dockerengine&scope=repository:samalba/my-app:pull,push
HTTP/1.1 200 OK
Content-Type: application/json
{"refresh_token":"kas9Da81Dfa8","access_token":"eyJhbGciOiJFUzI1NiIsInR5":"expires_in":"900","scope":"repository:samalba/my-app:pull,repository:samalba/my-app:push"}
````

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<!--[metadata]>
+++
title = "Token Scope Documentation"
description = "Describes the scope and access fields used for registry authorization tokens"
keywords = ["registry, on-prem, images, tags, repository, distribution, advanced, access, scope"]
[menu.main]
parent="smn_registry_ref"
+++
<![end-metadata]-->
# Docker Registry Token Scope and Access
Tokens used by the registry are always restricted what resources they may
be used to access, where those resources may be accessed, and what actions
may be done on those resources. Tokens always have the context of a user which
the token was originally created for. This document describes how these
restrictions are represented and enforced by the authorization server and
resource providers.
## Scope Components
### Subject (Authenticated User)
The subject represents the user for which a token is valid. Any actions
performed using an access token should be considered on behalf of the subject.
This is included in the `sub` field of access token JWT. A refresh token should
be limited to a single subject and only be able to give out access tokens for
that subject.
### Audience (Resource Provider)
The audience represents a resource provider which is intended to be able to
perform the actions specified in the access token. Any resource provider which
does not match the audience should not use that access token. The audience is
included in the `aud` field of the access token JWT. A refresh token should be
limited to a single audience and only be able to give out access tokens for that
audience.
### Resource Type
The resource type represents the type of resource which the resource name is
intended to represent. This type may be specific to a resource provider but must
be understood by the authorization server in order to validate the subject
is authorized for a specific resource.
#### Example Resource Types
- `repository` - represents a single repository within a registry. A
repository may represent many manifest or content blobs, but the resource type
is considered the collections of those items. Actions which may be performed on
a `repository` are `pull` for accessing the collection and `push` for adding to
it.
### Resource Name
The resource name represent the name which identifies a resource for a resource
provider. A resource is identified by this name and the provided resource type.
An example of a resource name would be the name component of an image tag, such
as "samalba/myapp".
### Resource Actions
The resource actions define the actions which the access token allows to be
performed on the identified resource. These actions are type specific but will
normally have actions identifying read and write access on the resource. Example
for the `repository` type are `pull` for read access and `push` for write
access.
## Authorization Server Use
Each access token request may include a scope and an audience. The subject is
always derived from the passed in credentials or refresh token. When using
a refresh token the passed in audience must match the audience defined for
the refresh token. The audience (resource provider) is provided using the
`service` field. Multiple resource scopes may be provided using multiple `scope`
fields on the `GET` request. The `POST` request only takes in a single
`scope` field but may use a space to separate a list of multiple resource
scopes.
### Resource Scope Grammar
```
scope := resourcescope [ ' ' resourcescope ]*
resourcescope := resourcetype ":" resourcename ":" action [ ',' action ]*
resourcetype := /[a-z]*/
resourcename := component [ '/' component ]*
action := /[a-z]*/
component := alpha-numeric [ separator alpha-numeric ]*
alpha-numeric := /[a-z0-9]+/
separator := /[_.]|__|[-]*/
```
Full reference grammar is defined
(here)[https://godoc.org/github.com/docker/distribution/reference]. Currently
the scope name grammar is a subset of the reference grammar without support
for hostnames.
## Resource Provider Use
Once a resource provider has verified the authenticity of the scope through
JWT access token verification, the resource provider must ensure that scope
satisfies the request. The resource provider should match the given audience
according to name or URI the resource provider uses to identify itself. Any
denial based on subject is not defined here and is up to resource provider, the
subject is mainly provided for audit logs and any other user-specific rules
which may need to be provided but are not defined by the authorization server.
The resource provider must ensure that ANY resource being accessed as the
result of a request has the appropriate access scope. Both the resource type
and resource name must match the accessed resource and an appropriate action
scope must be included.
When appropriate authorization is not provided either due to lack of scope
or missing token, the resource provider to return a `WWW-AUTHENTICATE` HTTP
header with the `realm` as the authorization server, the `service` as the
expected audience identifying string, and a `scope` field for each required
resource scope to complete the request.
## JWT Access Tokens
Each JWT access token may only have a single subject and audience but multiple
resource scopes. The subject and audience are put into standard JWT fields
`sub` and `aud`. The resource scope is put into the `access` field. The
structure of the access field can be seen in the
[jwt documentation](jwt.md).
## Refresh Tokens
A refresh token must be defined for a single subject and audience. Further
restricting scope to specific type, name, and actions combinations should be
done by fetching an access token using the refresh token. Since the refresh
token is not scoped to specific resources for an audience, extra care should
be taken to only use the refresh token to negotiate new access tokens directly
with the authorization server, and never with a resource provider.

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@ -91,6 +91,8 @@ challenge, the client will need to make a `GET` request to the URL
## Requesting a Token
Defines getting a bearer and refresh token using the token endpoint.
#### Query Parameters
<dl>
@ -100,6 +102,25 @@ challenge, the client will need to make a `GET` request to the URL
<dd>
The name of the service which hosts the resource.
</dd>
<dt>
<code>offline_token</code>
</dt>
<dd>
Whether to return a refresh token along with the bearer token. A refresh
token is capable of getting additional bearer tokens for the same
subject with different scopes. The refresh token does not have an
expiration and should be considered completely opaque to the client.
</dd>
<dt>
<code>client_id</code>
</dt>
<dd>
String identifying the client. This client_id does not need
to be registered with the authorization server but should be set to a
meaningful value in order to allow auditing keys created by unregistered
clients. Accepted syntax is defined in
[RFC6749 Appendix A.1](https://tools.ietf.org/html/rfc6749#appendix-A.1).
</dd>
<dt>
<code>scope</code>
</dt>
@ -109,7 +130,9 @@ challenge, the client will need to make a `GET` request to the URL
shown above. This query parameter should be specified multiple times if
there is more than one <code>scope</code> entry from the <code>WWW-Authenticate</code>
header. The above example would be specified as:
<code>scope=repository:samalba/my-app:push</code>.
<code>scope=repository:samalba/my-app:push</code>. The scope field may
be empty to request a refresh token without providing any resource
permissions to the returned bearer token.
</dd>
</dl>
@ -150,6 +173,16 @@ challenge, the client will need to make a `GET` request to the URL
standard time at which a given token was issued. If <code>issued_at</code> is omitted, the
expiration is from when the token exchange completed.
</dd>
<dt>
<code>refresh_token</code>
</dt>
<dd>
(Optional) Token which can be used to get additional access tokens for
the same subject with different scopes. This token should be kept secure
by the client and only sent to the authorization server which issues
bearer tokens. This field will only be set when `offline_token=true` is
provided in the request.
</dd>
</dl>
#### Example
@ -161,11 +194,12 @@ https://auth.docker.io/token?service=registry.docker.io&scope=repository:samalba
```
The token server should first attempt to authenticate the client using any
authentication credentials provided with the request. As of Docker 1.8, the
registry client in the Docker Engine only supports Basic Authentication to
these token servers. If an attempt to authenticate to the token server fails,
the token server should return a `401 Unauthorized` response indicating that
the provided credentials are invalid.
authentication credentials provided with the request. From Docker 1.11 the
Docker engine supports both Basic Authentication and [OAuth2](oauth.md) for
getting tokens. Docker 1.10 and before, the registry client in the Docker Engine
only supports Basic Authentication. If an attempt to authenticate to the token
server fails, the token server should return a `401 Unauthorized` response
indicating that the provided credentials are invalid.
Whether the token server requires authentication is up to the policy of that
access control provider. Some requests may require authentication to determine