feat: allow setting OIDC_CLIENT_SECRET_METHOD

app/utils/config/headplane.ts

@@ -28,6 +28,7 @@ export interface HeadplaneContext {
 		client: string
 		secret: string
 		rootKey: string
+		method: string
 		disableKeyLogin: boolean
 	}
 }
@@ -143,6 +144,7 @@ async function checkOidc(config?: HeadscaleConfig) {
 	let issuer = process.env.OIDC_ISSUER
 	let client = process.env.OIDC_CLIENT_ID
 	let secret = process.env.OIDC_CLIENT_SECRET
+	let method = process.env.OIDC_CLIENT_SECRET_METHOD ?? 'client_secret_basic'
 
 	log.debug('CTXT', 'Checking OIDC environment variables')
 	log.debug('CTXT', 'Issuer: %s', issuer)
@@ -161,6 +163,7 @@ async function checkOidc(config?: HeadscaleConfig) {
 			issuer,
 			client,
 			secret,
+			method,
 			rootKey,
 			disableKeyLogin,
 		}
@@ -204,6 +207,7 @@ async function checkOidc(config?: HeadscaleConfig) {
 		client,
 		secret,
 		rootKey,
+		method,
 		disableKeyLogin,
 	}
 }

app/utils/oidc.ts

@@ -36,7 +36,7 @@ export async function startOidc(oidc: OidcConfig, req: Request) {
 	const issuerUrl = new URL(oidc.issuer)
 	const oidcClient = {
 		client_id: oidc.client,
-		token_endpoint_auth_method: 'client_secret_basic',
+		token_endpoint_auth_method: oidc.method,
 	} satisfies Client
 
 	const response = await discoveryRequest(issuerUrl)
@@ -91,7 +91,7 @@ export async function finishOidc(oidc: OidcConfig, req: Request) {
 	const oidcClient = {
 		client_id: oidc.client,
 		client_secret: oidc.secret,
-		token_endpoint_auth_method: 'client_secret_basic',
+		token_endpoint_auth_method: oidc.method,
 	} satisfies Client
 
 	const response = await discoveryRequest(issuerUrl)

docs/Configuration.md

@@ -34,6 +34,7 @@ If you use the Headscale configuration integration, these are not required.
 - **`OIDC_ISSUER`**: The issuer URL of your OIDC provider.
 - **`OIDC_CLIENT_ID`**: The client ID of your OIDC provider.
 - **`OIDC_CLIENT_SECRET`**: The client secret of your OIDC provider.
+- **`OIDC_CLIENT_SECRET_METHOD`**: The method used to send the client secret (default: `client_secret_basic`).
 - **`ROOT_API_KEY`**: An API key used to issue new ones for sessions (keep expiry fairly long).
 - **`DISABLE_API_KEY_LOGIN`**: If you want to disable API key login, set this to `true`.