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mod_http_oauth2: Make storage of various code more consistent
I'm not sure how any of this worked at all.
author | Kim Alvefur <zash@zash.se> |
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date | Sun, 06 Aug 2023 12:07:05 +0200 |
parent | 5624:d8622797e315 |
child | 5652:f3b7e05c74a9 |
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--- labels: - Stage-Alpha rockspec: build: copy_directories: - html summary: OAuth 2.0 Authorization Server API --- ## Introduction This module implements an [OAuth2](https://oauth.net/2/)/[OpenID Connect (OIDC)](https://openid.net/connect/) provider HTTP frontend on top of Prosody's usual internal authentication backend. OAuth and OIDC are web standards that allow you to provide clients and third-party applications limited access to your account, without sharing your password with them. With this module deployed, software that supports OAuth can obtain "access tokens" from Prosody which can then be used to connect to XMPP accounts using the [OAUTHBEARER SASL mechanism][rfc7628] or via non-XMPP interfaces such as [mod_rest]. Although this module has been around for some time, it has recently been significantly extended and largely rewritten to support OAuth/OIDC more fully. As of April 2023, it should be considered **alpha** stage. It works, we have tested it, but it has not yet seen wider review, testing and deployment. At this stage we recommend it for experimental and test deployments only. For specific information, see the [deployment notes section](#deployment-notes) below. Known client implementations: - [example shell script for mod_rest](https://hg.prosody.im/prosody-modules/file/tip/mod_rest/example/rest.sh) - *(we need you!)* Support for [OAUTHBEARER][rfc7628] has been added to the Lua XMPP library, [verse](https://code.matthewwild.co.uk/verse). If you know of additional implementations, or are motivated to work on one, please let us know! We'd be happy to help (e.g. by providing a test server). ## Standards support Notable supported standards: - [RFC 6749: The OAuth 2.0 Authorization Framework](https://www.rfc-editor.org/rfc/rfc6749) - [RFC 7009: OAuth 2.0 Token Revocation](https://www.rfc-editor.org/rfc/rfc7009) - [RFC 7591: OAuth 2.0 Dynamic Client Registration](https://www.rfc-editor.org/rfc/rfc7591.html) - [RFC 7628: A Set of Simple Authentication and Security Layer (SASL) Mechanisms for OAuth](https://www.rfc-editor.org/rfc/rfc7628) - [RFC 7636: Proof Key for Code Exchange by OAuth Public Clients](https://www.rfc-editor.org/rfc/rfc7636) - [RFC 8628: OAuth 2.0 Device Authorization Grant](https://www.rfc-editor.org/rfc/rfc8628) - [RFC 9207: OAuth 2.0 Authorization Server Issuer Identification](https://www.rfc-editor.org/rfc/rfc9207.html) - [OpenID Connect Core 1.0](https://openid.net/specs/openid-connect-core-1_0.html) - [OpenID Connect Discovery 1.0](https://openid.net/specs/openid-connect-discovery-1_0.html) (_partial, e.g. missing JWKS_) - [OpenID Connect Dynamic Client Registration 1.0](https://openid.net/specs/openid-connect-registration-1_0.html) ## Configuration ### Interface The module presents a web page to users to allow them to authenticate when a client requests access. Built-in pages are provided, but you may also theme or entirely override them. This module honours the `site_name` configuration option that is also used by a number of other modules: ```lua site_name = "My XMPP Server" ``` To provide custom templates, specify the path to the template directory: ```lua oauth2_template_path = "/etc/prosody/custom-oauth2-templates" ``` Some templates support additional variables, that can be provided by the `oauth2_template_style` option: ```lua oauth2_template_style = { background_colour = "#ffffff"; } ``` If you know what features your templates use use you can adjust the `Content-Security-Policy` header to only allow what is needed: ```lua oauth2_security_policy = "default-src 'self'" -- this is the default ``` ### Token parameters The following options configure the lifetime of tokens issued by the module. The defaults are recommended. ```lua oauth2_access_token_ttl = 3600 -- one hour oauth2_refresh_token_ttl = 604800 -- one week ``` ### Dynamic client registration To allow users to connect any compatible software, you should enable dynamic client registration. Dynamic client registration can be enabled by configuring a JWT key. Algorithm defaults to *HS256* lifetime defaults to forever. ```lua oauth2_registration_key = "securely generated JWT key here" oauth2_registration_algorithm = "HS256" oauth2_registration_ttl = nil -- unlimited by default ``` Registering a client is described in [RFC7591](https://www.rfc-editor.org/rfc/rfc7591.html). In addition to the requirements in the RFC, the following requirements are enforced: `client_name` : **MUST** be present, is shown to users in consent screen. `client_uri` : **MUST** be present and **MUST** be a `https://` URL. `redirect_uris` : **MUST** contain at least one valid URI. Different rules apply depending on the value of `application_type`, see below. `application_type` : Optional, defaults to `web`. Determines further restrictions for `redirect_uris`. The following values are supported: `web` *(default)* : For web clients. With this, `redirect_uris` **MUST** be `https://` URIs and **MUST** use the same hostname part as the `client_uri`. `native` `native` : For native e.g. desktop clients etc. `redirect_uris` **MUST** match one of: - Loopback HTTP URI, e.g. `http://127.0.0.1/` or `http://[::1]` - Application-specific scheme, e.g. `com.example.app:/` - The special OOB URI `urn:ietf:wg:oauth:2.0:oob` `tos_uri`, `policy_uri` : Informative URLs pointing to Terms of Service and Service Policy document **MUST** use the same scheme (i.e. `https://`) and hostname as the `client_uri`. #### Registration Examples In short registration works by POST-ing a JSON structure describing your client to an endpoint: ``` bash curl -sSf https://xmpp.example.net/oauth2/register \ -H Content-Type:application/json \ -H Accept:application/json \ --data ' { "client_name" : "My Application", "client_uri" : "https://app.example.com/", "redirect_uris" : [ "https://app.example.com/redirect" ] } ' ``` Another example with more fields: ``` bash curl -sSf https://xmpp.example.net/oauth2/register \ -H Content-Type:application/json \ -H Accept:application/json \ --data ' { "application_type" : "native", "client_name" : "Desktop Chat App", "client_uri" : "https://app.example.org/", "contacts" : [ "support@example.org" ], "policy_uri" : "https://app.example.org/about/privacy", "redirect_uris" : [ "http://localhost:8080/redirect", "org.example.app:/redirect" ], "scope" : "xmpp", "software_id" : "32a0a8f3-4016-5478-905a-c373156eca73", "software_version" : "3.4.1", "tos_uri" : "https://app.example.org/about/terms" } ' ``` ### Supported flows - Authorization Code grant, optionally with Proof Key for Code Exchange - Device Authorization Grant - Resource owner password grant *(likely to be phased out in the future)* - Implicit flow *(disabled by default)* - Refresh Token grants Various flows can be disabled and enabled with `allowed_oauth2_grant_types` and `allowed_oauth2_response_types`: ```lua -- These examples reflect the defaults allowed_oauth2_grant_types = { "authorization_code"; -- authorization code grant "device_code"; "password"; -- resource owner password grant } allowed_oauth2_response_types = { "code"; -- authorization code flow -- "token"; -- implicit flow disabled by default } ``` The [Proof Key for Code Exchange][RFC 7636] mitigation method is optional by default but can be made required: ```lua oauth2_require_code_challenge = true -- default is false ``` Further, individual challenge methods can be enabled or disabled: ```lua -- These reflects the default allowed_oauth2_code_challenge_methods = { "plain"; -- the insecure one "S256"; } ``` ### Policy documents Links to Terms of Service and Service Policy documents can be advertised for use by OAuth clients: ```lua oauth2_terms_url = "https://example.com/terms-of-service.html" oauth2_policy_url = "https://example.com/service-policy.pdf" -- These are unset by default ``` ## Deployment notes ### Access management This module does not provide an interface for users to manage what they have granted access to their account! (e.g. to view and revoke clients they have previously authorized). It is recommended to join this module with [mod_client_management] to provide such access. However, at the time of writing, no XMPP clients currently support the protocol used by that module. We plan to work on additional interfaces in the future. ### Scopes OAuth supports "scopes" as a way to grant clients limited access. There are currently no standard scopes defined for XMPP. This is something that we intend to change, e.g. by definitions provided in a future XEP. This means that clients you authorize currently have to choose between unrestricted access to your account (including the ability to change your password and lock you out!) and zero access. So, for now, while using OAuth clients can prevent leaking your password to them, it is not currently suitable for connecting untrusted clients to your account. As a first step, the `xmpp` scope is supported, and corresponds to whatever permissions the user would have when logged in over XMPP. Further, known Prosody roles can be used as scopes. OpenID scopes such as `openid` and `profile` can be used for "Login with XMPP" without granting access to more than limited profile details. ## Compatibility Requires Prosody trunk (April 2023), **not** compatible with Prosody 0.12 or earlier.