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Toolbox API comes with a basic oauth2 client. This commit sets-up details about two important oauth flows: - authorization flow, in which the user is sent to web page where an authorization code is generated which is exchanged for an access token. - details about token refresh endpoint where users can obtain a new access token and a new refresh token. A couple of important aspects: - the client app id is resolved in upstream - as well as the actual endpoints for authorization and token refresh - S256 is the only code challenge supported
…ation url OAuth endpoint `.well-known/oauth-authorization-server` provides metadata about the endpoint for dynamic client registration and supported response types. This commit adds support for deserializing these values.
OAuth allows programatic client registration for apps like Coder Toolbox via the DCR endpoint which requires a name for the client app, the requested scopes, redirect URI, etc... DCR replies back with a similar structure but in addition it returs two very important properties: client_id - a unique client identifier string and also a client_secret - a secret string value used by clients to authenticate to the token endpoint.
Code Toolbox plugin should protect against authorization code interception attacks by making use of the PKCE security extension which involves a cryptographically random string (128 characters) known as code verifier and a code challenge - derived from code verifier using the S256 challenge method.
The OAuth2-compatible authentication manager provided by Toolbox
- authentication and token endpoints are now passed via the login configuration object - similar for client_id and client_secret - PCKE is now enabled
…injection - remove ServiceLocator dependency from CoderToolboxContext - move OAuth manager creation to CoderToolboxExtension for cleaner separation - Refactor CoderOAuthManager to use configuration-based approach instead of constructor injection The idea behind these changes is that createRefreshConfig API does not receive a configuration object that can provide the client id and secret and even the refresh url. So initially we worked around the issue by passing the necessary data via the constructor. However this approach means a couple of things: - the actual auth manager can be created only at a very late stage, when a URL is provided by users - can't easily pass arround the auth manager without coupling the components - have to recreate a new auth manager instance if the user logs out and logs in to a different URL - service locator needs to be passed around because this is the actual factory of oauth managers in Toolbox Instead, we went with a differet approach, COderOAuthManager will derive and store the refresh configs once the authorization config is received. If the user logs out and logs in to a different URL the refresh data is also guaranteed to be updated. And on top of that - this approach allows us to get rid of all of the issues mentioned above.
Toolbox can handle automatically the exchange of an authorization code with a token by handling the custom URI for oauth. This commit calls the necessary API in the Coder Toolbox URI handling.
POST /api/v2/oauth2-provider/apps is actually for manual admin registration for admin created apps. Programmatic Dynamic Client Registration is done via `POST /oauth2/register`. At the same time I included `registration_access_token` and `registration_client_uri` to use it later in order to refresh the client secret without re-registering the client app.
A bunch of code thrown around to launch the OAuth flow. Still needs a couple of things: - persist the client id and registration uri and token - re-use client id instead of re-register every time - properly handle scenarios where OAuth is not available - the OAuth right now can be enabled if we log out and then hit next in the deployment screen
A new config `preferAuthViaApiToken` allows users to continue to use API tokens for authentication when OAuth2 is available on the Coder deployment.
Account implementation with logic to resolve the account once the token is retrieved. Marshalling logic for the account is also added. There is a limitation in the Toolbox API where createRefreshConfig is not receiving the auth params. We worked around by capturing and storing these params in the createAuthConfig but this is unreliable. Instead we use the account to pass the missing info around.
OAuth2 should be launched if user prefers is over any other method of auth and if only the server supports it.
Fallback on client_secret_basic or None depending on what the Coder server supports.
…n endpoint Based on the auth method type we need to send client id and client secret as a basic auth header or part of the body as an encoded url form
We encountered a couple of issues with the Toolbox API which is inflexible:
- we don't have complete control over which parameters are sent as query&body
- we don't have fully basic + headers + body logging for debugging purposes
- doesn't integrate that well with our existing http client used for polling
- spent more than a couple of hours trying to understand why Coder rejects the
authorization call with:
```
{"error":"invalid_request","error_description":"The request is missing required parameters or is otherwise malformed"} from Coder server.
```
Instead we will slowly discard the existing logic and rely on enhancements to our existing http client.
Basically, the login screen will try to first determine if mTLS auth is configured and use that, otherwise
it will check if the user wants to use OAuth over API token, if available. When the flag is
true then the login screen will query the Coder server to see if OAuth2 is supported.
If that is true then browser is launched pointing to the authentication URL. If not we will default to
the API token authentication.
jeremyruppel
reviewed
Mar 6, 2026
zedkipp
reviewed
Mar 7, 2026
The OAuth2 server implementation needs to provide an authorization code that can be exchanged for an access token. But in order to make sure the authorization code is for the "our" login request, the client provides a state value when launching the authorization URL which the OAuth2 server has to send back when with the auth code. This fix makes sure the authorization code is actually sent, and that the state value is the same as in our initial request.
This fix reports an error to the user when token exchange request is failing, or returning an empty body or a body that does not contain the token.
The logic for exchanging auth code to tokens, refreshing tokens was used in multiple places without any code reuse strategy. Extracted an OAuth service that handles the basic operations.
The metadata endpoint provide an absolute URL for the client registration endpoint which we should use instead of hardcoding the path relative to the base url.
ThomasK33
reviewed
Mar 17, 2026
https://datatracker.ietf.org/doc/html/rfc7591 normalizes the client registration error responses and forces providers to always include json with an error code and an error message. This patch captures the error response and builds a pretty message and displays it to the user.
RFC 6749 §4.1.2.1 + RFC 7636 §4.4.1 specify that the error code and optional error_description can be returned as a query params int the callback URI. Similarly, RFC 6749 §5.2 — the exchange of authorization codes to tokens can return a json body containing an error code and an error message that was never handled in our code.
This upgrade will need TBX 3.4 or higher to be installed. The upgrade is needed to benefit from the fixes related to displaying UI pages in the URI handler. In addition I reworked the main build.gradle and extracted everything into a small custom plugin.
Due to the dependency on the new API.
OAuth callbacks are encoded, especially error details need to be decoded before surfacing them to the user.
We ended up with error messages like `An error was encountered: <error-code>: <some error description`. ":" is a bit repetitive.
matifali
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Apr 6, 2026
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Non-engineering approval. I am fine shipping this, given its opt-in.
Just ensure we provide a good experience in case the setting is enabled, but the deployment does not have CODER_EXPERIMENTS=aouth2 enabled.
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Yes, I can confirm that OAuth happens only when the user explicitly enables the OAuth authentication AND the backed exposes the necessary endpoints. |
fioan89
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Go's html/template has a built-in security filter (urlFilter) that only allows http, https, and mailto URL schemes. Any other scheme gets replaced with #ZgotmplZ. The OAuth2 app's callback URL uses custom URI scheme which the filter considers unsafe. For example the Coder JetBrains plugin exposes a callback URI with the scheme jetbrains:// - which was effectively changed by the template engine into #ZgotmplZ. Of course this is not an actual callback. When users clicked the cancel button nothing happened. The fix was simple - we now wrap the apps registered callback URI into htmltemplate.URL. In addition, while testing this PR with coder/coder-jetbrains-toolbox#209 I discovered that we are also not compliant with https://www.rfc-editor.org/rfc/rfc6749#section-4.1.2.1 which requires the server to attach the local state if it was provided by the client in the original request. Also it is optional but generally a good practice to include `error_description` in the error responses. In fact we follow this pattern for the other types of error responses. So this is not a one off.
code-asher
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Apr 6, 2026
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I ran out of time but will finish tomorrow!
| else -> ClientAuth.None(oauthSessionContext.clientId) | ||
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| val service = createAuthorizationService() |
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Is there a reason we need to create a new service here rather than use the one on the class? Or should we update the service on the class with this new one?
| throw Exception(errorMessage) | ||
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| private fun createAuthorizationService(): CoderAuthorizationApi { |
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This is a nit, but when I initially saw the oauth2 auth service create yet another auth service it seemed weird to me, but this is really just an http/api client right? Not really doing any service-like things, I think?
In my mind it would involve state management to be a service, which has implications for how it should behave in the code (which is why I thought maybe it was a problem to recreate it above without updating the one on the class).
I guess in that sense OAuth2Service is not necessarily a service either, just a wrapper around the API calls. Actually, could these all be methods directly on the coder rest client? Feels to me like it could be part of the sdk, they are just more API endpoints after all.
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| val newAuthResponse = OAuth2Service(context).refreshToken(oauthContext!!) | ||
| this.oauthContext.tokenResponse = newAuthResponse |
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nbd at all but we use oauthContext without a this and then this.oauthContext, is there a reason for that?
I know I always say this haha but !! feels like a trap waiting to spring in the future, maybe we could pass in the context to refreshToken() or something?
| block() | ||
| try { | ||
| val response = block() | ||
| if (response.code() == HttpURLConnection.HTTP_UNAUTHORIZED && oauthContext.hasRefreshToken()) { |
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If oauthContext is nullable would this not require a ?? Should we do an oauthContext.let or something? Would also let us get rid of that !! if we pass that around.
But I assume it must not require it since it is building, just not sure how haha
| private suspend fun refreshToken() { | ||
| val newAuthResponse = OAuth2Service(context).refreshToken(oauthContext!!) | ||
| this.oauthContext.tokenResponse = newAuthResponse | ||
| onTokenRefreshed?.invoke(url, oauthContext) |
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Probably not a big deal at all, but it could be kinda weird that onTokenRefreshed could technically mutate the context. refreshToken could too, technically.
| refreshToken() | ||
| true | ||
| } catch (e: Exception) { | ||
| context.logger.error(e, "Failed to refresh access token") |
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If the refresh fails, do we need to look at the response and possibly discard the token? If it is some kind of permanent auth failure. Otherwise I imagine we would keep trying to refresh with the same token.
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Recent versions of Coder act as an OAuth 2.1 authorization server for first- and third‑party applications.
This PR aims at providing support for authenticating via OAuth with Coder Toolbox and still retain backward compatibility for authentication via API tokens or via certificates.
This PR is a WIP: