## Summary
This PR implements critical MCP OAuth2 compliance features for Coder's authorization server, adding PKCE support, resource parameter handling, and OAuth2 server metadata discovery. This brings Coder's OAuth2 implementation significantly closer to production readiness for MCP (Model Context Protocol)
integrations.
## What's Added
### OAuth2 Authorization Server Metadata (RFC 8414)
- Add `/.well-known/oauth-authorization-server` endpoint for automatic client discovery
- Returns standardized metadata including supported grant types, response types, and PKCE methods
- Essential for MCP client compatibility and OAuth2 standards compliance
### PKCE Support (RFC 7636)
- Implement Proof Key for Code Exchange with S256 challenge method
- Add `code_challenge` and `code_challenge_method` parameters to authorization flow
- Add `code_verifier` validation in token exchange
- Provides enhanced security for public clients (mobile apps, CLIs)
### Resource Parameter Support (RFC 8707)
- Add `resource` parameter to authorization and token endpoints
- Store resource URI and bind tokens to specific audiences
- Critical for MCP's resource-bound token model
### Enhanced OAuth2 Error Handling
- Add OAuth2-compliant error responses with proper error codes
- Use standard error format: `{"error": "code", "error_description": "details"}`
- Improve error consistency across OAuth2 endpoints
### Authorization UI Improvements
- Fix authorization flow to use POST-based consent instead of GET redirects
- Remove dependency on referer headers for security decisions
- Improve CSRF protection with proper state parameter validation
## Why This Matters
**For MCP Integration:** MCP requires OAuth2 authorization servers to support PKCE, resource parameters, and metadata discovery. Without these features, MCP clients cannot securely authenticate with Coder.
**For Security:** PKCE prevents authorization code interception attacks, especially critical for public clients. Resource binding ensures tokens are only valid for intended services.
**For Standards Compliance:** These are widely adopted OAuth2 extensions that improve interoperability with modern OAuth2 clients.
## Database Changes
- **Migration 000343:** Adds `code_challenge`, `code_challenge_method`, `resource_uri` to `oauth2_provider_app_codes`
- **Migration 000343:** Adds `audience` field to `oauth2_provider_app_tokens` for resource binding
- **Audit Updates:** New OAuth2 fields properly tracked in audit system
- **Backward Compatibility:** All changes maintain compatibility with existing OAuth2 flows
## Test Coverage
- Comprehensive PKCE test suite in `coderd/identityprovider/pkce_test.go`
- OAuth2 metadata endpoint tests in `coderd/oauth2_metadata_test.go`
- Integration tests covering PKCE + resource parameter combinations
- Negative tests for invalid PKCE verifiers and malformed requests
## Testing Instructions
```bash
# Run the comprehensive OAuth2 test suite
./scripts/oauth2/test-mcp-oauth2.sh
Manual Testing with Interactive Server
# Start Coder in development mode
./scripts/develop.sh
# In another terminal, set up test app and run interactive flow
eval $(./scripts/oauth2/setup-test-app.sh)
./scripts/oauth2/test-manual-flow.sh
# Opens browser with OAuth2 flow, handles callback automatically
# Clean up when done
./scripts/oauth2/cleanup-test-app.sh
Individual Component Testing
# Test metadata endpoint
curl -s http://localhost:3000/.well-known/oauth-authorization-server | jq .
# Test PKCE generation
./scripts/oauth2/generate-pkce.sh
# Run specific test suites
go test -v ./coderd/identityprovider -run TestVerifyPKCE
go test -v ./coderd -run TestOAuth2AuthorizationServerMetadata
```
### Breaking Changes
None. All changes maintain backward compatibility with existing OAuth2 flows.
---
Change-Id: Ifbd0d9a543d545f9f56ecaa77ff2238542ff954a
Signed-off-by: Thomas Kosiewski <tk@coder.com>
First PR in a series to address
https://github.com/coder/coder/issues/16230.
Introduces support for logging in via the [GitHub OAuth2 Device
Flow](https://docs.github.com/en/apps/oauth-apps/building-oauth-apps/authorizing-oauth-apps#device-flow).
It's previously been possible to configure external auth with the device
flow, but it's not been possible to use it for logging in. This PR
builds on the existing support we had to extend it to sign ins.
When a user clicks "sign in with GitHub" when device auth is configured,
they are redirected to the new `/login/device` page, which makes the
flow possible from the client's side. The recording below shows the full
flow.
https://github.com/user-attachments/assets/90c06f1f-e42f-43e9-a128-462270c80fdd
I've also manually tested that it works for converting from
password-based auth to oauth.
Device auth can be enabled by a deployment's admin by setting the
`CODER_OAUTH2_GITHUB_DEVICE_FLOW` env variable or a corresponding config
setting.
* Add database tables for OAuth2 applications
These are applications that will be able to use OAuth2 to get an API key
from Coder.
* Add endpoints for managing OAuth2 applications
These let you add, update, and remove OAuth2 applications.
* Add frontend for managing OAuth2 applications
* chore: add /v2 to import module path
go mod requires semantic versioning with versions greater than 1.x
This was a mechanical update by running:
```
go install github.com/marwan-at-work/mod/cmd/mod@latest
mod upgrade
```
Migrate generated files to import /v2
* Fix gen
This commit:
- Allows configuring the OIDC claim Coder uses for email addresses (by default, this is still email)
- Allows customising the parameters sent to the upstream identity provider when requesting a token. This is still access_type=offline by default.
- Updates documentation related to the above.
* chore: rename `AgentConn` to `WorkspaceAgentConn`
The codersdk was becoming bloated with consts for the workspace
agent that made no sense to a reader. `Tailnet*` is an example
of these consts.
* chore: remove `Get` prefix from *Client functions
* chore: remove `BypassRatelimits` option in `codersdk.Client`
It feels wrong to have this as a direct option because it's so infrequently
needed by API callers. It's better to directly modify headers in the two
places that we actually use it.
* Merge `appearance.go` and `buildinfo.go` into `deployment.go`
* Merge `experiments.go` and `features.go` into `deployment.go`
* Fix `make gen` referencing old type names
* Merge `error.go` into `client.go`
`codersdk.Response` lived in `error.go`, which is wrong.
* chore: refactor workspace agent functions into agentsdk
It was odd conflating the codersdk that clients should use
with functions that only the agent should use. This separates
them into two SDKs that are closely coupled, but separate.
* Merge `insights.go` into `deployment.go`
* Merge `organizationmember.go` into `organizations.go`
* Merge `quota.go` into `workspaces.go`
* Rename `sse.go` to `serversentevents.go`
* Rename `codersdk.WorkspaceAppHostResponse` to `codersdk.AppHostResponse`
* Format `.vscode/settings.json`
* Fix outdated naming in `api.ts`
* Fix app host response
* Fix unsupported type
* Fix imported type
