Add Supervisor upstream IDP discovery on the server-side

internal/oidc/discovery/discovery_handler.go

@@ -1,4 +1,4 @@
-// Copyright 2020 the Pinniped contributors. All Rights Reserved.
+// Copyright 2020-2021 the Pinniped contributors. All Rights Reserved.
 // SPDX-License-Identifier: Apache-2.0
 
 // Package discovery provides a handler for the OIDC discovery endpoint.
@@ -8,10 +8,16 @@ import (
 	"bytes"
 	"encoding/json"
 	"net/http"
+	"sort"
 
 	"go.pinniped.dev/internal/oidc"
 )
 
+const (
+	idpDiscoveryTypeLDAP = "ldap"
+	idpDiscoveryTypeOIDC = "oidc"
+)
+
 // Metadata holds all fields (that we care about) from the OpenID Provider Metadata section in the
 // OpenID Connect Discovery specification:
 // https://openid.net/specs/openid-connect-discovery-1_0.html#rfc.section.3.
@@ -37,33 +43,28 @@ type Metadata struct {
 	ClaimsSupported                   []string `json:"claims_supported"`
 
 	// ^^^ Optional ^^^
+
+	// vvv Custom vvv
+
+	IDPs []IdentityProviderMetadata `json:"pinniped_idps"`
+
+	// ^^^ Custom ^^^
+}
+
+type IdentityProviderMetadata struct {
+	Name string `json:"name"`
+	Type string `json:"type"`
 }
 
 // NewHandler returns an http.Handler that serves an OIDC discovery endpoint.
-func NewHandler(issuerURL string) http.Handler {
+func NewHandler(issuerURL string, upstreamIDPs oidc.UpstreamIdentityProvidersLister) http.Handler {
-	oidcConfig := Metadata{
-		Issuer:                            issuerURL,
-		AuthorizationEndpoint:             issuerURL + oidc.AuthorizationEndpointPath,
-		TokenEndpoint:                     issuerURL + oidc.TokenEndpointPath,
-		JWKSURI:                           issuerURL + oidc.JWKSEndpointPath,
-		ResponseTypesSupported:            []string{"code"},
-		SubjectTypesSupported:             []string{"public"},
-		IDTokenSigningAlgValuesSupported:  []string{"ES256"},
-		TokenEndpointAuthMethodsSupported: []string{"client_secret_basic"},
-		ScopesSupported:                   []string{"openid", "offline"},
-		ClaimsSupported:                   []string{"groups"},
-	}
-
-	var b bytes.Buffer
-	encodeErr := json.NewEncoder(&b).Encode(&oidcConfig)
-	encodedMetadata := b.Bytes()
-
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		if r.Method != http.MethodGet {
 			http.Error(w, `Method not allowed (try GET)`, http.StatusMethodNotAllowed)
 			return
 		}
 
+		encodedMetadata, encodeErr := metadata(issuerURL, upstreamIDPs)
 		if encodeErr != nil {
 			http.Error(w, encodeErr.Error(), http.StatusInternalServerError)
 			return
@@ -76,3 +77,38 @@ func NewHandler(issuerURL string) http.Handler {
 		}
 	})
 }
+
+func metadata(issuerURL string, upstreamIDPs oidc.UpstreamIdentityProvidersLister) ([]byte, error) {
+	oidcConfig := Metadata{
+		Issuer:                            issuerURL,
+		AuthorizationEndpoint:             issuerURL + oidc.AuthorizationEndpointPath,
+		TokenEndpoint:                     issuerURL + oidc.TokenEndpointPath,
+		JWKSURI:                           issuerURL + oidc.JWKSEndpointPath,
+		ResponseTypesSupported:            []string{"code"},
+		SubjectTypesSupported:             []string{"public"},
+		IDTokenSigningAlgValuesSupported:  []string{"ES256"},
+		TokenEndpointAuthMethodsSupported: []string{"client_secret_basic"},
+		ScopesSupported:                   []string{"openid", "offline"},
+		ClaimsSupported:                   []string{"groups"},
+		IDPs:                              []IdentityProviderMetadata{},
+	}
+
+	// The cache of IDPs could change at any time, so always recalculate the list.
+	for _, provider := range upstreamIDPs.GetLDAPIdentityProviders() {
+		oidcConfig.IDPs = append(oidcConfig.IDPs, IdentityProviderMetadata{Name: provider.GetName(), Type: idpDiscoveryTypeLDAP})
+	}
+	for _, provider := range upstreamIDPs.GetOIDCIdentityProviders() {
+		oidcConfig.IDPs = append(oidcConfig.IDPs, IdentityProviderMetadata{Name: provider.GetName(), Type: idpDiscoveryTypeOIDC})
+	}
+
+	// Nobody like an API that changes the results unnecessarily. :)
+	sort.SliceStable(oidcConfig.IDPs, func(i, j int) bool {
+		return oidcConfig.IDPs[i].Name < oidcConfig.IDPs[j].Name
+	})
+
+	var b bytes.Buffer
+	encodeErr := json.NewEncoder(&b).Encode(&oidcConfig)
+	encodedMetadata := b.Bytes()
+
+	return encodedMetadata, encodeErr
+}

internal/oidc/discovery/discovery_handler_test.go

@@ -1,4 +1,4 @@
-// Copyright 2020 the Pinniped contributors. All Rights Reserved.
+// Copyright 2020-2021 the Pinniped contributors. All Rights Reserved.
 // SPDX-License-Identifier: Apache-2.0
 
 package discovery
@@ -9,6 +9,10 @@ import (
 	"net/http/httptest"
 	"testing"
 
+	"go.pinniped.dev/internal/oidc/provider"
+
+	"go.pinniped.dev/internal/testutil/oidctestutil"
+
 	"github.com/stretchr/testify/require"
 
 	"go.pinniped.dev/internal/oidc"
@@ -24,7 +28,8 @@ func TestDiscovery(t *testing.T) {
 
 		wantStatus                 int
 		wantContentType            string
-		wantBodyJSON    interface{}
+		wantFirstResponseBodyJSON  interface{}
+		wantSecondResponseBodyJSON interface{}
 		wantBodyString             string
 	}{
 		{
@@ -34,7 +39,7 @@ func TestDiscovery(t *testing.T) {
 			path:            "/some/path" + oidc.WellKnownEndpointPath,
 			wantStatus:      http.StatusOK,
 			wantContentType: "application/json",
-			wantBodyJSON: &Metadata{
+			wantFirstResponseBodyJSON: &Metadata{
 				Issuer:                            "https://some-issuer.com/some/path",
 				AuthorizationEndpoint:             "https://some-issuer.com/some/path/oauth2/authorize",
 				TokenEndpoint:                     "https://some-issuer.com/some/path/oauth2/token",
@@ -45,6 +50,32 @@ func TestDiscovery(t *testing.T) {
 				TokenEndpointAuthMethodsSupported: []string{"client_secret_basic"},
 				ScopesSupported:                   []string{"openid", "offline"},
 				ClaimsSupported:                   []string{"groups"},
+				IDPs: []IdentityProviderMetadata{
+					{Name: "a-some-ldap-idp", Type: "ldap"},
+					{Name: "a-some-oidc-idp", Type: "oidc"},
+					{Name: "x-some-idp", Type: "ldap"},
+					{Name: "x-some-idp", Type: "oidc"},
+					{Name: "z-some-ldap-idp", Type: "ldap"},
+					{Name: "z-some-oidc-idp", Type: "oidc"},
+				},
+			},
+			wantSecondResponseBodyJSON: &Metadata{
+				Issuer:                            "https://some-issuer.com/some/path",
+				AuthorizationEndpoint:             "https://some-issuer.com/some/path/oauth2/authorize",
+				TokenEndpoint:                     "https://some-issuer.com/some/path/oauth2/token",
+				JWKSURI:                           "https://some-issuer.com/some/path/jwks.json",
+				ResponseTypesSupported:            []string{"code"},
+				SubjectTypesSupported:             []string{"public"},
+				IDTokenSigningAlgValuesSupported:  []string{"ES256"},
+				TokenEndpointAuthMethodsSupported: []string{"client_secret_basic"},
+				ScopesSupported:                   []string{"openid", "offline"},
+				ClaimsSupported:                   []string{"groups"},
+				IDPs: []IdentityProviderMetadata{
+					{Name: "some-other-ldap-idp-1", Type: "ldap"},
+					{Name: "some-other-ldap-idp-2", Type: "ldap"},
+					{Name: "some-other-oidc-idp-1", Type: "oidc"},
+					{Name: "some-other-oidc-idp-2", Type: "oidc"},
+				},
 			},
 		},
 		{
@@ -60,7 +91,16 @@ func TestDiscovery(t *testing.T) {
 	for _, test := range tests {
 		test := test
 		t.Run(test.name, func(t *testing.T) {
-			handler := NewHandler(test.issuer)
+			idpLister := oidctestutil.NewUpstreamIDPListerBuilder().
+				WithOIDC(&oidctestutil.TestUpstreamOIDCIdentityProvider{Name: "z-some-oidc-idp"}).
+				WithOIDC(&oidctestutil.TestUpstreamOIDCIdentityProvider{Name: "x-some-idp"}).
+				WithLDAP(&oidctestutil.TestUpstreamLDAPIdentityProvider{Name: "a-some-ldap-idp"}).
+				WithOIDC(&oidctestutil.TestUpstreamOIDCIdentityProvider{Name: "a-some-oidc-idp"}).
+				WithLDAP(&oidctestutil.TestUpstreamLDAPIdentityProvider{Name: "z-some-ldap-idp"}).
+				WithLDAP(&oidctestutil.TestUpstreamLDAPIdentityProvider{Name: "x-some-idp"}).
+				Build()
+
+			handler := NewHandler(test.issuer, idpLister)
 			req := httptest.NewRequest(test.method, test.path, nil)
 			rsp := httptest.NewRecorder()
 			handler.ServeHTTP(rsp, req)
@@ -69,8 +109,36 @@ func TestDiscovery(t *testing.T) {
 
 			require.Equal(t, test.wantContentType, rsp.Header().Get("Content-Type"))
 
-			if test.wantBodyJSON != nil {
+			if test.wantFirstResponseBodyJSON != nil {
-				wantJSON, err := json.Marshal(test.wantBodyJSON)
+				wantJSON, err := json.Marshal(test.wantFirstResponseBodyJSON)
+				require.NoError(t, err)
+				require.JSONEq(t, string(wantJSON), rsp.Body.String())
+			}
+
+			if test.wantBodyString != "" {
+				require.Equal(t, test.wantBodyString, rsp.Body.String())
+			}
+
+			// Change the list of IDPs in the cache.
+			idpLister.SetLDAPIdentityProviders([]provider.UpstreamLDAPIdentityProviderI{
+				&oidctestutil.TestUpstreamLDAPIdentityProvider{Name: "some-other-ldap-idp-1"},
+				&oidctestutil.TestUpstreamLDAPIdentityProvider{Name: "some-other-ldap-idp-2"},
+			})
+			idpLister.SetOIDCIdentityProviders([]provider.UpstreamOIDCIdentityProviderI{
+				&oidctestutil.TestUpstreamOIDCIdentityProvider{Name: "some-other-oidc-idp-1"},
+				&oidctestutil.TestUpstreamOIDCIdentityProvider{Name: "some-other-oidc-idp-2"},
+			})
+
+			// Make the same request to the same handler instance again, and expect different results.
+			rsp = httptest.NewRecorder()
+			handler.ServeHTTP(rsp, req)
+
+			require.Equal(t, test.wantStatus, rsp.Code)
+
+			require.Equal(t, test.wantContentType, rsp.Header().Get("Content-Type"))
+
+			if test.wantFirstResponseBodyJSON != nil {
+				wantJSON, err := json.Marshal(test.wantSecondResponseBodyJSON)
 				require.NoError(t, err)
 				require.JSONEq(t, string(wantJSON), rsp.Body.String())
 			}

internal/oidc/provider/manager/manager.go

@@ -102,7 +102,7 @@ func (m *Manager) SetProviders(federationDomains ...*provider.FederationDomainIs
 			wrapGetter(incomingProvider.Issuer(), m.secretCache.GetStateEncoderBlockKey),
 		)
 
-		m.providerHandlers[(issuerHostWithPath + oidc.WellKnownEndpointPath)] = discovery.NewHandler(issuer)
+		m.providerHandlers[(issuerHostWithPath + oidc.WellKnownEndpointPath)] = discovery.NewHandler(issuer, m.upstreamIDPs)
 
 		m.providerHandlers[(issuerHostWithPath + oidc.JWKSEndpointPath)] = jwks.NewHandler(issuer, m.dynamicJWKSProvider)
 

internal/oidc/provider/manager/manager_test.go

@@ -52,6 +52,8 @@ func TestManager(t *testing.T) {
 			issuer2DifferentCaseHostname = "https://exAmPlE.Com/some/path/more/deeply/nested/path"
 			issuer2KeyID                 = "issuer2-key"
 			upstreamIDPAuthorizationURL  = "https://test-upstream.com/auth"
+			upstreamIDPName              = "test-idp"
+			upstreamIDPType              = "oidc"
 			downstreamClientID           = "pinniped-cli"
 			downstreamRedirectURL        = "http://127.0.0.1:12345/callback"
 
@@ -68,7 +70,7 @@ func TestManager(t *testing.T) {
 			return req
 		}
 
-		requireDiscoveryRequestToBeHandled := func(requestIssuer, requestURLSuffix, expectedIssuerInResponse string) {
+		requireDiscoveryRequestToBeHandled := func(requestIssuer, requestURLSuffix, expectedIssuer, expectedIDPName, expectedIDPType string) {
 			recorder := httptest.NewRecorder()
 
 			subject.ServeHTTP(recorder, newGetRequest(requestIssuer+oidc.WellKnownEndpointPath+requestURLSuffix))
@@ -82,7 +84,10 @@ func TestManager(t *testing.T) {
 			parsedDiscoveryResult := discovery.Metadata{}
 			err = json.Unmarshal(responseBody, &parsedDiscoveryResult)
 			r.NoError(err)
-			r.Equal(expectedIssuerInResponse, parsedDiscoveryResult.Issuer)
+			r.Equal(expectedIssuer, parsedDiscoveryResult.Issuer)
+			r.Len(parsedDiscoveryResult.IDPs, 1)
+			r.Equal(expectedIDPName, parsedDiscoveryResult.IDPs[0].Name)
+			r.Equal(expectedIDPType, parsedDiscoveryResult.IDPs[0].Type)
 		}
 
 		requireAuthorizationRequestToBeHandled := func(requestIssuer, requestURLSuffix, expectedRedirectLocationPrefix string) (string, string) {
@@ -222,7 +227,7 @@ func TestManager(t *testing.T) {
 			parsedUpstreamIDPAuthorizationURL, err := url.Parse(upstreamIDPAuthorizationURL)
 			r.NoError(err)
 			idpLister := oidctestutil.NewUpstreamIDPListerBuilder().WithOIDC(&oidctestutil.TestUpstreamOIDCIdentityProvider{
-				Name:             "test-idp",
+				Name:             upstreamIDPName,
 				ClientID:         "test-client-id",
 				AuthorizationURL: *parsedUpstreamIDPAuthorizationURL,
 				Scopes:           []string{"test-scope"},
@@ -284,14 +289,14 @@ func TestManager(t *testing.T) {
 		}
 
 		requireRoutesMatchingRequestsToAppropriateProvider := func() {
-			requireDiscoveryRequestToBeHandled(issuer1, "", issuer1)
+			requireDiscoveryRequestToBeHandled(issuer1, "", issuer1, upstreamIDPName, upstreamIDPType)
-			requireDiscoveryRequestToBeHandled(issuer2, "", issuer2)
+			requireDiscoveryRequestToBeHandled(issuer2, "", issuer2, upstreamIDPName, upstreamIDPType)
-			requireDiscoveryRequestToBeHandled(issuer2, "?some=query", issuer2)
+			requireDiscoveryRequestToBeHandled(issuer2, "?some=query", issuer2, upstreamIDPName, upstreamIDPType)
 
 			// Hostnames are case-insensitive, so test that we can handle that.
-			requireDiscoveryRequestToBeHandled(issuer1DifferentCaseHostname, "", issuer1)
+			requireDiscoveryRequestToBeHandled(issuer1DifferentCaseHostname, "", issuer1, upstreamIDPName, upstreamIDPType)
-			requireDiscoveryRequestToBeHandled(issuer2DifferentCaseHostname, "", issuer2)
+			requireDiscoveryRequestToBeHandled(issuer2DifferentCaseHostname, "", issuer2, upstreamIDPName, upstreamIDPType)
-			requireDiscoveryRequestToBeHandled(issuer2DifferentCaseHostname, "?some=query", issuer2)
+			requireDiscoveryRequestToBeHandled(issuer2DifferentCaseHostname, "?some=query", issuer2, upstreamIDPName, upstreamIDPType)
 
 			issuer1JWKS := requireJWKSRequestToBeHandled(issuer1, "", issuer1KeyID)
 			issuer2JWKS := requireJWKSRequestToBeHandled(issuer2, "", issuer2KeyID)

test/integration/supervisor_discovery_test.go

@@ -483,7 +483,8 @@ func requireWellKnownEndpointIsWorking(t *testing.T, supervisorScheme, superviso
       "response_types_supported": ["code"],
       "claims_supported": ["groups"],
       "subject_types_supported": ["public"],
-      "id_token_signing_alg_values_supported": ["ES256"]
+      "id_token_signing_alg_values_supported": ["ES256"],
+	  "pinniped_idps": []
     }`)
 	expectedJSON := fmt.Sprintf(expectedResultTemplate, issuerName, issuerName, issuerName, issuerName)