fix: use policy engine in oauth whitelist check (#904)

Author: steveiliop56

internal/bootstrap/service_bootstrap.go

@@ -42,7 +42,7 @@ func (app *BootstrapApp) setupServices() error {
 	oauthBrokerService := service.NewOAuthBrokerService(app.log, app.runtime.OAuthProviders, app.ctx)
 	app.services.oauthBrokerService = oauthBrokerService
 
-	authService := service.NewAuthService(app.log, app.config, app.runtime, app.ctx, &app.wg, app.services.ldapService, app.queries, app.services.oauthBrokerService, app.services.tailscaleService)
+	authService := service.NewAuthService(app.log, app.config, app.runtime, app.ctx, &app.wg, app.services.ldapService, app.queries, app.services.oauthBrokerService, app.services.tailscaleService, app.services.policyEngine)
 	app.services.authService = authService
 
 	oidcService, err := service.NewOIDCService(app.log, app.config, app.runtime, app.queries, app.ctx, &app.wg)

internal/controller/proxy_controller_test.go

@@ -357,7 +357,6 @@ func TestProxyController(t *testing.T) {
 	ctx := context.TODO()
 
 	broker := service.NewOAuthBrokerService(log, map[string]model.OAuthServiceConfig{}, ctx)
-	authService := service.NewAuthService(log, cfg, runtime, ctx, wg, nil, store, broker, nil)
 	aclsService := service.NewAccessControlsService(log, cfg, nil)
 
 	policyEngine, err := service.NewPolicyEngine(cfg, log)
@@ -383,6 +382,8 @@ func TestProxyController(t *testing.T) {
 		Log: log,
 	})
 
+	authService := service.NewAuthService(log, cfg, runtime, ctx, wg, nil, store, broker, nil, policyEngine)
+
 	for _, test := range tests {
 		t.Run(test.description, func(t *testing.T) {
 			router := gin.Default()

internal/controller/user_controller_test.go

@@ -414,8 +414,11 @@ func TestUserController(t *testing.T) {
 	ctx := context.TODO()
 	wg := &sync.WaitGroup{}
 
+	policyEngine, err := service.NewPolicyEngine(cfg, log)
+	require.NoError(t, err)
+
 	broker := service.NewOAuthBrokerService(log, map[string]model.OAuthServiceConfig{}, ctx)
-	authService := service.NewAuthService(log, cfg, runtime, ctx, wg, nil, store, broker, nil)
+	authService := service.NewAuthService(log, cfg, runtime, ctx, wg, nil, store, broker, nil, policyEngine)
 
 	beforeEach := func() {
 		// Clear failed login attempts before each test

internal/middleware/context_middleware_test.go

@@ -254,8 +254,11 @@ func TestContextMiddleware(t *testing.T) {
 
 	store := memory.New()
 
+	policyEngine, err := service.NewPolicyEngine(cfg, log)
+	require.NoError(t, err)
+
 	broker := service.NewOAuthBrokerService(log, map[string]model.OAuthServiceConfig{}, ctx)
-	authService := service.NewAuthService(log, cfg, runtime, ctx, wg, nil, store, broker, nil)
+	authService := service.NewAuthService(log, cfg, runtime, ctx, wg, nil, store, broker, nil, policyEngine)
 
 	contextMiddleware := middleware.NewContextMiddleware(log, runtime, authService, broker, nil)
 

internal/service/auth_service.go

@@ -75,10 +75,11 @@ type AuthService struct {
 	runtime model.RuntimeConfig
 	context context.Context
 
-	ldap        *LdapService
-	queries     repository.Store
-	oauthBroker *OAuthBrokerService
-	tailscale   *TailscaleService
+	ldap         *LdapService
+	queries      repository.Store
+	oauthBroker  *OAuthBrokerService
+	tailscale    *TailscaleService
+	policyEngine *PolicyEngine
 
 	loginAttempts        map[string]*LoginAttempt
 	ldapGroupsCache      map[string]*LdapGroupsCache
@@ -101,6 +102,7 @@ func NewAuthService(
 	queries repository.Store,
 	oauthBroker *OAuthBrokerService,
 	tailscale *TailscaleService,
+	policy *PolicyEngine,
 ) *AuthService {
 	service := &AuthService{
 		log:                  log,
@@ -114,6 +116,7 @@ func NewAuthService(
 		queries:              queries,
 		oauthBroker:          oauthBroker,
 		tailscale:            tailscale,
+		policyEngine:         policy,
 	}
 
 	wg.Go(service.CleanupOAuthSessionsRoutine)
@@ -285,18 +288,27 @@ func (auth *AuthService) RecordLoginAttempt(identifier string, success bool) {
 	}
 }
 
+// We could also directly access the policyEngine.effectToAccess but
+// I believe it's better to use the exported functions instead
 func (auth *AuthService) IsEmailWhitelisted(provider string, email string) bool {
-	whitelist := auth.runtime.OAuthWhitelist
-	if providerConfig, ok := auth.runtime.OAuthProviders[provider]; ok && len(providerConfig.Whitelist) > 0 {
-		whitelist = providerConfig.Whitelist
-	}
-
-	match, err := utils.CheckFilter(strings.Join(whitelist, ","), email)
-	if err != nil {
-		auth.log.App.Warn().Err(err).Str("provider", provider).Str("email", email).Msg("Invalid email filter pattern")
-		return false
-	}
-	return match
+	return auth.policyEngine.EvaluateFunc(func() Effect {
+		whitelist := auth.runtime.OAuthWhitelist
+		if providerConfig, ok := auth.runtime.OAuthProviders[provider]; ok && len(providerConfig.Whitelist) > 0 {
+			whitelist = providerConfig.Whitelist
+		}
+		match, err := utils.CheckFilter(strings.Join(whitelist, ","), email)
+		if err != nil {
+			if err == utils.ErrFilterEmpty {
+				return EffectAbstain
+			}
+			auth.log.App.Error().Err(err).Str("email", email).Msg("Failed to evaluate email whitelist filter, defaulting to deny")
+			return EffectDeny
+		}
+		if match {
+			return EffectAllow
+		}
+		return EffectDeny
+	})
 }
 
 func (auth *AuthService) CreateSession(ctx context.Context, data repository.Session) (*http.Cookie, error) {

internal/service/policy_engine.go

@@ -108,3 +108,7 @@ func (engine *PolicyEngine) Policy() Policy {
 func (engine *PolicyEngine) Rules() map[RuleName]Rule {
 	return engine.rules
 }
+
+func (engine *PolicyEngine) EvaluateFunc(f func() Effect) bool {
+	return engine.effectToAccess(f())
+}

internal/utils/security_utils.go

@@ -3,6 +3,7 @@ package utils
 import (
 	"crypto/rand"
 	"encoding/base64"
+	"errors"
 	"fmt"
 	"net"
 	"regexp"
@@ -11,6 +12,10 @@ import (
 	"github.com/google/uuid"
 )
 
+var (
+	ErrFilterEmpty = errors.New("filter is empty")
+)
+
 func GetSecret(conf string, file string) string {
 	if conf == "" && file == "" {
 		return ""
@@ -78,7 +83,7 @@ func CheckIPFilter(filter string, ip string) (bool, error) {
 
 func CheckFilter(filter string, input string) (bool, error) {
 	if len(strings.TrimSpace(filter)) == 0 {
-		return false, fmt.Errorf("filter is empty")
+		return false, ErrFilterEmpty
 	}
 
 	if strings.HasPrefix(filter, "/") && strings.HasSuffix(filter, "/") {