Guard against open redirect URL parameters in login

flyteadmin/auth/handler_utils.go

@@ -8,6 +8,7 @@ import (
 	"github.com/grpc-ecosystem/go-grpc-middleware/util/metautils"
 
 	"github.com/flyteorg/flyte/flyteadmin/auth/config"
+	"github.com/flyteorg/flyte/flytestdlib/logger"
 )
 
 const (
@@ -146,3 +147,32 @@ func GetPublicURL(ctx context.Context, req *http.Request, cfg *config.Config) *u
 
 	return u
 }
+
+func isAuthorizedRedirectURL(url *url.URL, authorizedURL *url.URL) bool {
+	return url.Hostname() == authorizedURL.Hostname() && url.Port() == authorizedURL.Port() && url.Scheme == authorizedURL.Scheme
+}
+
+func GetRedirectURLAllowed(ctx context.Context, redirectParam string, cfg *config.Config) bool {
+	if len(redirectParam) == 0 {
+		logger.Debugf(ctx, "not validating whether empty redirect url is authorized")
+		return true
+	}
+	redirectURL, err := url.Parse(redirectParam)
+	if err != nil {
+		logger.Debugf(ctx, "failed to parse user-supplied redirect url: %s with err: %v", redirectParam, err)
+		return false
+	}
+	if redirectURL.Host == "" {
+		logger.Debugf(ctx, "not validating whether relative redirect url is authorized")
+		return true
+	}
+	logger.Debugf(ctx, "validating whether redirectURL: %s is authorized", redirectURL)
+	for _, authorizedURI := range cfg.AuthorizedURIs {
+		if isAuthorizedRedirectURL(redirectURL, &authorizedURI.URL) {
+			logger.Debugf(ctx, "authorizing url: %s against authorized uri: %s", redirectURL.String(), authorizedURI.String())
+			return true
+		}
+	}
+	logger.Debugf(ctx, "not authorizing url: %s", redirectURL.String())
+	return false
+}

flyteadmin/auth/handler_utils_test.go

@@ -8,15 +8,15 @@ import (
 	"github.com/stretchr/testify/assert"
 
 	"github.com/flyteorg/flyte/flyteadmin/auth/config"
-	config2 "github.com/flyteorg/flyte/flytestdlib/config"
+	flytestdconfig "github.com/flyteorg/flyte/flytestdlib/config"
 )
 
 func TestGetPublicURL(t *testing.T) {
 	t.Run("Matching scheme and host", func(t *testing.T) {
 		req, err := http.NewRequest(http.MethodPost, "https://abc", nil)
 		assert.NoError(t, err)
 		u := GetPublicURL(context.Background(), req, &config.Config{
-			AuthorizedURIs: []config2.URL{
+			AuthorizedURIs: []flytestdconfig.URL{
 				{URL: *config.MustParseURL("https://xyz")},
 				{URL: *config.MustParseURL("https://abc")},
 			},
@@ -28,7 +28,7 @@ func TestGetPublicURL(t *testing.T) {
 		req, err := http.NewRequest(http.MethodPost, "https://abc", nil)
 		assert.NoError(t, err)
 		u := GetPublicURL(context.Background(), req, &config.Config{
-			AuthorizedURIs: []config2.URL{
+			AuthorizedURIs: []flytestdconfig.URL{
 				{URL: *config.MustParseURL("https://xyz")},
 				{URL: *config.MustParseURL("http://abc")},
 			},
@@ -40,7 +40,7 @@ func TestGetPublicURL(t *testing.T) {
 		req, err := http.NewRequest(http.MethodPost, "https://abc", nil)
 		assert.NoError(t, err)
 		u := GetPublicURL(context.Background(), req, &config.Config{
-			AuthorizedURIs: []config2.URL{
+			AuthorizedURIs: []flytestdconfig.URL{
 				{URL: *config.MustParseURL("https://xyz")},
 				{URL: *config.MustParseURL("http://xyz")},
 			},
@@ -61,7 +61,7 @@ func TestGetPublicURL(t *testing.T) {
 
 		assert.NoError(t, err)
 		u := GetPublicURL(context.Background(), req, &config.Config{
-			AuthorizedURIs: []config2.URL{
+			AuthorizedURIs: []flytestdconfig.URL{
 				{URL: *config.MustParseURL("http://flyteadmin:80")},
 				{URL: *config.MustParseURL("http://localhost:30081")},
 				{URL: *config.MustParseURL("http://localhost:8089")},
@@ -72,3 +72,28 @@ func TestGetPublicURL(t *testing.T) {
 		assert.Equal(t, "http://localhost:30081", u.String())
 	})
 }
+
+func TestGetRedirectURLAllowed(t *testing.T) {
+	ctx := context.TODO()
+	t.Run("relative url", func(t *testing.T) {
+		assert.True(t, GetRedirectURLAllowed(ctx, "/console", &config.Config{}))
+	})
+	t.Run("no redirect url", func(t *testing.T) {
+		assert.True(t, GetRedirectURLAllowed(ctx, "", &config.Config{}))
+	})
+	cfg := &config.Config{
+		AuthorizedURIs: []flytestdconfig.URL{
+			{URL: *config.MustParseURL("https://example.com")},
+			{URL: *config.MustParseURL("http://localhost:3008")},
+		},
+	}
+	t.Run("authorized url", func(t *testing.T) {
+		assert.True(t, GetRedirectURLAllowed(ctx, "https://example.com", cfg))
+	})
+	t.Run("authorized localhost url", func(t *testing.T) {
+		assert.True(t, GetRedirectURLAllowed(ctx, "http://localhost:3008", cfg))
+	})
+	t.Run("unauthorized url", func(t *testing.T) {
+		assert.False(t, GetRedirectURLAllowed(ctx, "https://flyte.com", cfg))
+	})
+}

flyteadmin/auth/handlers.go

@@ -141,6 +141,11 @@ func GetLoginHandler(ctx context.Context, authCtx interfaces.AuthenticationConte
 		logger.Debugf(ctx, "Setting CSRF state cookie to %s and state to %s\n", csrfToken, state)
 		url := authCtx.OAuth2ClientConfig(GetPublicURL(ctx, request, authCtx.Options())).AuthCodeURL(state)
 		queryParams := request.URL.Query()
+		if !GetRedirectURLAllowed(ctx, queryParams.Get(RedirectURLParameter), authCtx.Options()) {
+			logger.Errorf(ctx, "unauthorized redirect URI")
+			writer.WriteHeader(http.StatusForbidden)
+			return
+		}
 		if flowEndRedirectURL := queryParams.Get(RedirectURLParameter); flowEndRedirectURL != "" {
 			redirectCookie := NewRedirectCookie(ctx, flowEndRedirectURL)
 			if redirectCookie != nil {