[management,proxy] Use single-use codes for OIDC session handoff (#7635)

* Generalize PKCE verifier store into SingleUseStore

* Generalize PKCE verifier store into SingleUseStore

* Extend single-use store to generate one-time retrieval codes

* Hand off proxy OIDC session via one-time code instead of URL token

* Use the single-use store in integration tests

* Read active proxy versions by cluster

* Detect proxy clusters that support session codes

* Bind OIDC session handoff mode to signed state

* Deprecate legacy OIDC session token handoff

* Remove unrelated session code test stub

* fix tests

* fix merge

* Fix session code compatibility detection

* Isolate proxy session codes in shared cache

* bump min session version

management/server/http/handlers/proxy/auth.go

@@ -59,7 +59,7 @@ func (h *AuthCallbackHandler) handleCallback(w http.ResponseWriter, r *http.Requ
 
 	state := r.URL.Query().Get("state")
 
-	codeVerifier, originalURL, err := h.proxyService.ValidateState(state)
+	codeVerifier, originalURL, useSessionCode, err := h.proxyService.ValidateState(state)
 	if err != nil {
 		log.WithError(err).Error("OAuth callback state validation failed")
 		http.Error(w, "Invalid state parameter", http.StatusBadRequest)
@@ -119,10 +119,19 @@ func (h *AuthCallbackHandler) handleCallback(w http.ResponseWriter, r *http.Requ
 	redirectURL.Scheme = "https"
 
 	query := redirectURL.Query()
-	query.Set("session_token", sessionToken)
+	if useSessionCode {
+		code, ok := h.proxyService.GenerateSessionCode(sessionToken)
+		if !ok {
+			http.Error(w, "Failed to create session", http.StatusInternalServerError)
+			return
+		}
+		query.Set("session_code", code)
+	} else {
+		query.Set("session_token", sessionToken)
+	}
 	redirectURL.RawQuery = query.Encode()
 
-	log.WithField("redirect", redirectURL.Host).Debug("OAuth callback: redirecting user with session token")
+	log.WithField("redirect", redirectURL.Host).Debug("OAuth callback: redirecting user to proxy")
 	http.Redirect(w, r, redirectURL.String(), http.StatusFound)
 }
 

management/server/http/handlers/proxy/auth_callback_integration_test.go

@@ -181,6 +181,10 @@ func (m *testAccessLogManager) GetAllAccessLogs(_ context.Context, _, _ string,
 }
 
 func setupAuthCallbackTest(t *testing.T) *testSetup {
+	return setupAuthCallbackTestWithProxyManager(t, testSessionCodeManager{})
+}
+
+func setupAuthCallbackTestWithProxyManager(t *testing.T, proxyManager nbproxy.Manager) *testSetup {
 	t.Helper()
 
 	ctx := context.Background()
@@ -217,7 +221,7 @@ func setupAuthCallbackTest(t *testing.T) *testSetup {
 		nil,
 		usersManager,
 		nil,
-		nil,
+		proxyManager,
 		nil,
 	)
 
@@ -242,6 +246,15 @@ func setupAuthCallbackTest(t *testing.T) *testSetup {
 	}
 }
 
+type testSessionCodeManager struct {
+	nbproxy.Manager
+	supported bool
+}
+
+func (m testSessionCodeManager) ClusterSupportsSessionCode(_ context.Context, _ string) bool {
+	return m.supported
+}
+
 func createTestReverseProxies(t *testing.T, ctx context.Context, testStore store.Store) {
 	t.Helper()
 
@@ -252,10 +265,11 @@ func createTestReverseProxies(t *testing.T, ctx context.Context, testStore store
 	privKey := base64.StdEncoding.EncodeToString(priv)
 
 	testProxy := &service.Service{
-		ID:        "testProxyId",
-		AccountID: "testAccountId",
-		Name:      "Test Proxy",
-		Domain:    "test-proxy.example.com",
+		ID:           "testProxyId",
+		AccountID:    "testAccountId",
+		Name:         "Test Proxy",
+		Domain:       "test-proxy.example.com",
+		ProxyCluster: "cluster.example.com",
 		Targets: []*service.Target{{
 			Path:       strPtr("/"),
 			Host:       "localhost",
@@ -512,29 +526,56 @@ func createTestState(t *testing.T, ps *nbgrpc.ProxyServiceServer, redirectURL st
 }
 
 func TestAuthCallback_UserAllowedToLogin(t *testing.T) {
-	setup := setupAuthCallbackTest(t)
-	defer setup.cleanup()
+	tests := []struct {
+		name        string
+		manager     nbproxy.Manager
+		wantParam   string
+		absentParam string
+	}{
+		{name: "legacy proxy", manager: testSessionCodeManager{}, wantParam: "session_token", absentParam: "session_code"},
+		{name: "compatible proxy", manager: testSessionCodeManager{supported: true}, wantParam: "session_code", absentParam: "session_token"},
+	}
 
-	setup.oidcServer.tokenSubject = "allowedUserId"
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			setup := setupAuthCallbackTestWithProxyManager(t, tt.manager)
+			defer setup.cleanup()
 
-	state := createTestState(t, setup.proxyService, "https://test-proxy.example.com/dashboard")
+			setup.oidcServer.tokenSubject = "allowedUserId"
+			state := createTestState(t, setup.proxyService, "https://test-proxy.example.com/dashboard")
+			req := httptest.NewRequest(http.MethodGet, "/reverse-proxy/callback?code=test-auth-code&state="+url.QueryEscape(state), nil)
+			rec := httptest.NewRecorder()
+			setup.router.ServeHTTP(rec, req)
+			require.Equal(t, http.StatusFound, rec.Code)
 
-	req := httptest.NewRequest(http.MethodGet, "/reverse-proxy/callback?code=test-auth-code&state="+url.QueryEscape(state), nil)
-	rec := httptest.NewRecorder()
+			location, err := url.Parse(rec.Header().Get("Location"))
+			require.NoError(t, err)
+			require.Equal(t, "test-proxy.example.com", location.Host)
+			require.NotEmpty(t, location.Query().Get(tt.wantParam))
+			require.Empty(t, location.Query().Get(tt.absentParam))
+			require.Empty(t, location.Query().Get("error"))
 
-	setup.router.ServeHTTP(rec, req)
+			if tt.wantParam == "session_code" {
+				code := location.Query().Get("session_code")
+				response, err := setup.proxyService.ValidateSession(context.Background(), &proto.ValidateSessionRequest{
+					Domain:      location.Hostname(),
+					SessionCode: code,
+				})
+				require.NoError(t, err)
+				require.True(t, response.GetValid())
+				require.NotEmpty(t, response.GetSessionToken())
+				require.NotEqual(t, code, response.GetSessionToken())
 
-	require.Equal(t, http.StatusFound, rec.Code)
-
-	location := rec.Header().Get("Location")
-	require.NotEmpty(t, location)
-
-	parsedLocation, err := url.Parse(location)
-	require.NoError(t, err)
-
-	require.Equal(t, "test-proxy.example.com", parsedLocation.Host)
-	require.NotEmpty(t, parsedLocation.Query().Get("session_token"), "Should include session token")
-	require.Empty(t, parsedLocation.Query().Get("error"), "Should not have error parameter")
+				replayed, err := setup.proxyService.ValidateSession(context.Background(), &proto.ValidateSessionRequest{
+					Domain:      location.Hostname(),
+					SessionCode: code,
+				})
+				require.NoError(t, err)
+				require.False(t, replayed.GetValid())
+				require.Empty(t, replayed.GetSessionToken())
+			}
+		})
+	}
 }
 
 // TestAuthCallback_UserDeniedByAccountStatus asserts that a user whose account