From 9497d3c03db13e72d4fcb6d5db93fa44e5b0288e Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?K=C3=A9vin=20Commaille?= Date: Wed, 18 Jun 2025 11:12:15 +0200 Subject: [PATCH] Move "Login flow" and "Refresh Token flow" as the first sections of OAuth 2.0 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Signed-off-by: Kévin Commaille --- content/client-server-api/_index.md | 336 ++++++++++++++-------------- 1 file changed, 168 insertions(+), 168 deletions(-) diff --git a/content/client-server-api/_index.md b/content/client-server-api/_index.md index 42c5eb17..714868f3 100644 --- a/content/client-server-api/_index.md +++ b/content/client-server-api/_index.md @@ -1481,6 +1481,174 @@ MAY reject weak passwords with an error code `M_WEAK_PASSWORD`. ### 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-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:` 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 +``` + + **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¶m2=value2`. +- If set to `query`, the parameters will be in placed the query string, like + `com.example.app:/callback?param1=value1¶m2=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 {{% 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 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-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:` 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 -``` - - **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¶m2=value2`. -- If set to `query`, the parameters will be in placed the query string, like - `com.example.app:/callback?param1=value1¶m2=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 locking