Move "Login flow" and "Refresh Token flow" as the first sections of OAuth 2.0

Signed-off-by: Kévin Commaille <zecakeh@tedomum.fr>
This commit is contained in:
Kévin Commaille 2025-06-18 11:12:15 +02:00
parent 572c2f3119
commit 9497d3c03d
No known key found for this signature in database
GPG key ID: F26F4BE20A08255B

View file

@ -1481,6 +1481,174 @@ MAY reject weak passwords with an error code `M_WEAK_PASSWORD`.
### OAuth 2.0 API ### OAuth 2.0 API
#### Login flow
Logging in with the OAuth 2.0 API should be done with the [authorization code
grant](#authorization-code-grant). In the context of the Matrix specification,
this means requesting a [scope](#scope) including full client-server API
read/write access and allocating a device ID.
Once the client has retrieved the [server metadata](#server-metadata-discovery),
it needs to generate the following values:
- `device_id`: a unique identifier for this device; see the
[`urn:matrix:client:device:<device_id>`](#device-id-allocation) scope token.
- `state`: a unique opaque identifier, like a [transaction ID](#transaction-identifiers),
that will allow the client to maintain state between the authorization request
and the callback.
- `code_verifier`: a cryptographically random value that will allow to make sure
that the client that makes the token request for a given `code` is the same
one that made the authorization request.
It is defined in [RFC 7636](https://datatracker.ietf.org/doc/html/rfc7636) as
a high-entropy cryptographic random string using the characters `[A-Z]`,
`[a-z]`, `[0-9]`, `-`, `.`, `_` and `~` with a minimum length of 43 characters
and a maximum length of 128 characters.
**Authorization request**
The client then constructs the authorization request URL using the
`authorization_endpoint` value, with the following query parameters:
| Parameter | Value |
|-------------------------|----------------------------------------------------|
| `response_type` | `code` |
| `client_id` | The client ID returned from client registration. |
| `redirect_uri` | The redirect URI that MUST match one of the values registered in the client metadata |
| `scope` | `urn:matrix:client:api:* urn:matrix:client:device:<device_id>` with the `device_id` generated previously. |
| `state` | The `state` value generated previously. |
| `response_mode` | `fragment` or `query` (see "[Callback](#callback)" below). |
| `code_challenge` | Computed from the `code_verifier` value generated previously using the SHA-256 algorithm, as described in [RFC 7636](https://datatracker.ietf.org/doc/html/rfc7636). |
| `code_challenge_method` | `S256` |
This authorization request URL must be opened in the user's browser:
- For web-based clients, this can be done through a redirection or by opening
the URL in a new tab.
- For native clients, this can be done by opening the URL using the system
browser, or, when available, through platform-specific APIs such as
[`ASWebAuthenticationSession`](https://developer.apple.com/documentation/authenticationservices/aswebauthenticationsession)
on iOS or [Android Custom Tabs](https://developer.chrome.com/docs/android/custom-tabs).
Sample authorization request, with extra whitespaces for readability:
```
https://account.example.com/oauth2/auth?
client_id = s6BhdRkqt3 &
response_type = code &
response_mode = fragment &
redirect_uri = https://app.example.com/oauth2-callback &
scope = urn:matrix:client:api:* urn:matrix:client:device:AAABBBCCCDDD &
state = ewubooN9weezeewah9fol4oothohroh3 &
code_challenge = 72xySjpngTcCxgbPfFmkPHjMvVDl2jW1aWP7-J6rmwU &
code_challenge_method = S256
```
<a id="callback"></a> **Callback**
Once completed, the user is redirected to the `redirect_uri`, with either a
successful or failed authorization in the URL fragment or query parameters.
Whether the parameters are in the URL fragment or query parameters is determined
by the `response_mode` value:
- If set to `fragment`, the parameters will be placed in the URL fragment, like
`https://example.com/callback#param1=value1&param2=value2`.
- If set to `query`, the parameters will be in placed the query string, like
`com.example.app:/callback?param1=value1&param2=value2`.
To avoid disclosing the parameters to the web server hosting the `redirect_uri`,
clients SHOULD use the `fragment` response mode if the `redirect_uri` is an
HTTPS URI with a remote host.
In both success and failure cases, the parameters will include the `state` value
used in the authorization request.
A successful authorization will have a `code` value, for example:
```
https://app.example.com/oauth2-callback#state=ewubooN9weezeewah9fol4oothohroh3&code=iuB7Eiz9heengah1joh2ioy9ahChuP6R
```
A failed authorization will have the following values:
- `error`: the error code
- `error_description`: the error description (optional)
- `error_uri`: the URI where the user can find more information about the error (optional)
For example:
```
https://app.example.com/oauth2-callback#state=ewubooN9weezeewah9fol4oothohroh3&error=access_denied&error_description=The+resource+owner+or+authorization+server+denied+the+request.&error_uri=https%3A%2F%2Ferrors.example.com%2F
```
**Token request**
The client then exchanges the authorization code to obtain an access token using
the token endpoint.
This is done by making a POST request to the `token_endpoint` with the following
parameters, encoded as `application/x-www-form-urlencoded` in the body:
| Parameter | Value |
|-----------------|------------------------------------------------------------|
| `grant_type` | `authorization_code` |
| `code` | The value of `code` obtained from the callback. |
| `redirect_uri` | The same `redirect_uri` used in the authorization request. |
| `client_id` | The client ID returned from client registration. |
| `code_verifier` | The value generated at the start of the authorization flow. |
The server replies with a JSON object containing the access token, the token
type, the expiration time, and the refresh token.
Sample token request:
```
POST /oauth2/token HTTP/1.1
Host: account.example.com
Content-Type: application/x-www-form-urlencoded
Accept: application/json
grant_type=authorization_code
&code=iuB7Eiz9heengah1joh2ioy9ahChuP6R
&redirect_uri=https://app.example.com/oauth2-callback
&client_id=s6BhdRkqt3
&code_verifier=ogie4iVaeteeKeeLaid0aizuimairaCh
```
Sample response:
```json
{
"access_token": "2YotnFZFEjr1zCsicMWpAA",
"token_type": "Bearer",
"expires_in": 299,
"refresh_token": "tGz3JOkF0XG5Qx2TlKWIA",
"scope": "urn:matrix:client:api:* urn:matrix:client:device:AAABBBCCCDDD"
}
```
Finally, the client can call the [`/whoami`](#get_matrixclientv3accountwhoami)
endpoint to get the user ID that owns the access token.
#### Token refresh flow
Refreshing a token with the OAuth 2.0 API should be done with the [refresh token
grant](#refresh-token-grant).
When the access token expires, the client must refresh it by making a `POST`
request to the `token_endpoint` with the following parameters, encoded as
`application/x-www-form-urlencoded` in the body:
| Parameter | Value |
|-----------------|------------------------------------------------------------|
| `grant_type` | `refresh_token` |
| `refresh_token` | The `refresh_token` obtained from the token response during the last token request. |
| `client_id` | The client ID returned from client registration. |
The server replies with a JSON object containing the new access token, the token
type, the expiration time, and a new refresh token, like in the authorization
flow.
#### Server metadata discovery #### Server metadata discovery
{{% http-api spec="client-server" api="oauth_server_metadata" %}} {{% http-api spec="client-server" api="oauth_server_metadata" %}}
@ -1653,174 +1821,6 @@ The client MUST handle access token refresh failures as follows:
- If the refresh fails due to a `4xx` HTTP status code from the server, the - If the refresh fails due to a `4xx` HTTP status code from the server, the
client should consider the session logged out. client should consider the session logged out.
#### Login flow
Logging in with the OAuth 2.0 API should be done with the [authorization code
grant](#authorization-code-grant). In the context of the Matrix specification,
this means requesting a [scope](#scope) including full client-server API
read/write access and allocating a device ID.
Once the client has retrieved the [server metadata](#server-metadata-discovery),
it needs to generate the following values:
- `device_id`: a unique identifier for this device; see the
[`urn:matrix:client:device:<device_id>`](#device-id-allocation) scope token.
- `state`: a unique opaque identifier, like a [transaction ID](#transaction-identifiers),
that will allow the client to maintain state between the authorization request
and the callback.
- `code_verifier`: a cryptographically random value that will allow to make sure
that the client that makes the token request for a given `code` is the same
one that made the authorization request.
It is defined in [RFC 7636](https://datatracker.ietf.org/doc/html/rfc7636) as
a high-entropy cryptographic random string using the characters `[A-Z]`,
`[a-z]`, `[0-9]`, `-`, `.`, `_` and `~` with a minimum length of 43 characters
and a maximum length of 128 characters.
**Authorization request**
The client then constructs the authorization request URL using the
`authorization_endpoint` value, with the following query parameters:
| Parameter | Value |
|-------------------------|----------------------------------------------------|
| `response_type` | `code` |
| `client_id` | The client ID returned from client registration. |
| `redirect_uri` | The redirect URI that MUST match one of the values registered in the client metadata |
| `scope` | `urn:matrix:client:api:* urn:matrix:client:device:<device_id>` with the `device_id` generated previously. |
| `state` | The `state` value generated previously. |
| `response_mode` | `fragment` or `query` (see "[Callback](#callback)" below). |
| `code_challenge` | Computed from the `code_verifier` value generated previously using the SHA-256 algorithm, as described in [RFC 7636](https://datatracker.ietf.org/doc/html/rfc7636). |
| `code_challenge_method` | `S256` |
This authorization request URL must be opened in the user's browser:
- For web-based clients, this can be done through a redirection or by opening
the URL in a new tab.
- For native clients, this can be done by opening the URL using the system
browser, or, when available, through platform-specific APIs such as
[`ASWebAuthenticationSession`](https://developer.apple.com/documentation/authenticationservices/aswebauthenticationsession)
on iOS or [Android Custom Tabs](https://developer.chrome.com/docs/android/custom-tabs).
Sample authorization request, with extra whitespaces for readability:
```
https://account.example.com/oauth2/auth?
client_id = s6BhdRkqt3 &
response_type = code &
response_mode = fragment &
redirect_uri = https://app.example.com/oauth2-callback &
scope = urn:matrix:client:api:* urn:matrix:client:device:AAABBBCCCDDD &
state = ewubooN9weezeewah9fol4oothohroh3 &
code_challenge = 72xySjpngTcCxgbPfFmkPHjMvVDl2jW1aWP7-J6rmwU &
code_challenge_method = S256
```
<a id="callback"></a> **Callback**
Once completed, the user is redirected to the `redirect_uri`, with either a
successful or failed authorization in the URL fragment or query parameters.
Whether the parameters are in the URL fragment or query parameters is determined
by the `response_mode` value:
- If set to `fragment`, the parameters will be placed in the URL fragment, like
`https://example.com/callback#param1=value1&param2=value2`.
- If set to `query`, the parameters will be in placed the query string, like
`com.example.app:/callback?param1=value1&param2=value2`.
To avoid disclosing the parameters to the web server hosting the `redirect_uri`,
clients SHOULD use the `fragment` response mode if the `redirect_uri` is an
HTTPS URI with a remote host.
In both success and failure cases, the parameters will include the `state` value
used in the authorization request.
A successful authorization will have a `code` value, for example:
```
https://app.example.com/oauth2-callback#state=ewubooN9weezeewah9fol4oothohroh3&code=iuB7Eiz9heengah1joh2ioy9ahChuP6R
```
A failed authorization will have the following values:
- `error`: the error code
- `error_description`: the error description (optional)
- `error_uri`: the URI where the user can find more information about the error (optional)
For example:
```
https://app.example.com/oauth2-callback#state=ewubooN9weezeewah9fol4oothohroh3&error=access_denied&error_description=The+resource+owner+or+authorization+server+denied+the+request.&error_uri=https%3A%2F%2Ferrors.example.com%2F
```
**Token request**
The client then exchanges the authorization code to obtain an access token using
the token endpoint.
This is done by making a POST request to the `token_endpoint` with the following
parameters, encoded as `application/x-www-form-urlencoded` in the body:
| Parameter | Value |
|-----------------|------------------------------------------------------------|
| `grant_type` | `authorization_code` |
| `code` | The value of `code` obtained from the callback. |
| `redirect_uri` | The same `redirect_uri` used in the authorization request. |
| `client_id` | The client ID returned from client registration. |
| `code_verifier` | The value generated at the start of the authorization flow. |
The server replies with a JSON object containing the access token, the token
type, the expiration time, and the refresh token.
Sample token request:
```
POST /oauth2/token HTTP/1.1
Host: account.example.com
Content-Type: application/x-www-form-urlencoded
Accept: application/json
grant_type=authorization_code
&code=iuB7Eiz9heengah1joh2ioy9ahChuP6R
&redirect_uri=https://app.example.com/oauth2-callback
&client_id=s6BhdRkqt3
&code_verifier=ogie4iVaeteeKeeLaid0aizuimairaCh
```
Sample response:
```json
{
"access_token": "2YotnFZFEjr1zCsicMWpAA",
"token_type": "Bearer",
"expires_in": 299,
"refresh_token": "tGz3JOkF0XG5Qx2TlKWIA",
"scope": "urn:matrix:client:api:* urn:matrix:client:device:AAABBBCCCDDD"
}
```
Finally, the client can call the [`/whoami`](#get_matrixclientv3accountwhoami)
endpoint to get the user ID that owns the access token.
#### Token refresh flow
Refreshing a token with the OAuth 2.0 API should be done with the [refresh token
grant](#refresh-token-grant).
When the access token expires, the client must refresh it by making a `POST`
request to the `token_endpoint` with the following parameters, encoded as
`application/x-www-form-urlencoded` in the body:
| Parameter | Value |
|-----------------|------------------------------------------------------------|
| `grant_type` | `refresh_token` |
| `refresh_token` | The `refresh_token` obtained from the token response during the last token request. |
| `client_id` | The client ID returned from client registration. |
The server replies with a JSON object containing the new access token, the token
type, the expiration time, and a new refresh token, like in the authorization
flow.
### Account moderation ### Account moderation
#### Account locking #### Account locking