fix: prevent nil pointer when err session retrieval fails

see https://sentry.in.nuonet.fr/share/issue/48b82c13ee3f4721bb6306b533799709/

internal/config/layers.go

@@ -21,6 +21,9 @@ func NewDefaultLayersConfig() LayersConfig {
 					Timeout:         NewInterpolatedDuration(10 * time.Second),
 				},
 			},
+			Sessions: AuthnLayerSessionConfig{
+				TTL: NewInterpolatedDuration(time.Hour),
+			},
 		},
 	}
 }
@@ -31,9 +34,14 @@ type QueueLayerConfig struct {
 }
 
 type AuthnLayerConfig struct {
-	Debug       InterpolatedBool     `yaml:"debug"`
-	TemplateDir InterpolatedString   `yaml:"templateDir"`
-	OIDC        AuthnOIDCLayerConfig `yaml:"oidc"`
+	Debug       InterpolatedBool        `yaml:"debug"`
+	TemplateDir InterpolatedString      `yaml:"templateDir"`
+	OIDC        AuthnOIDCLayerConfig    `yaml:"oidc"`
+	Sessions    AuthnLayerSessionConfig `yaml:"sessions"`
+}
+
+type AuthnLayerSessionConfig struct {
+	TTL *InterpolatedDuration `yaml:"ttl"`
 }
 
 type AuthnOIDCLayerConfig struct {

internal/session/options.go

@@ -10,6 +10,7 @@ import (
 type Options struct {
 	Session   sessions.Options
 	KeyPrefix string
+	TTL       time.Duration
 }
 
 type OptionFunc func(opts *Options)
@@ -25,6 +26,7 @@ func NewOptions(funcs ...OptionFunc) *Options {
 			SameSite: http.SameSiteDefaultMode,
 		},
 		KeyPrefix: "session:",
+		TTL:       time.Hour,
 	}
 
 	for _, fn := range funcs {
@@ -45,3 +47,9 @@ func WithKeyPrefix(prefix string) OptionFunc {
 		opts.KeyPrefix = prefix
 	}
 }
+
+func WithTTL(ttl time.Duration) OptionFunc {
+	return func(opts *Options) {
+		opts.TTL = ttl
+	}
+}

internal/session/store.go

@@ -31,6 +31,7 @@ type Store struct {
 	keyPrefix  string
 	keyGen     KeyGenFunc
 	serializer SessionSerializer
+	ttl        time.Duration
 }
 
 type KeyGenFunc func() (string, error)
@@ -43,6 +44,7 @@ func NewStore(adapter StoreAdapter, funcs ...OptionFunc) *Store {
 		keyPrefix:  opts.KeyPrefix,
 		keyGen:     generateRandomKey,
 		serializer: GobSerializer{},
+		ttl:        opts.TTL,
 	}
 
 	return rs
@@ -62,20 +64,21 @@ func (s *Store) New(r *http.Request, name string) (*sessions.Session, error) {
 	if err != nil {
 		return session, nil
 	}
+
 	session.ID = c.Value
 
 	err = s.load(r.Context(), session)
 	if err == nil {
 		session.IsNew = false
 	} else if !errors.Is(err, ErrNotFound) {
-		return nil, errors.WithStack(err)
+		return session, errors.WithStack(err)
 	}
 
 	return session, nil
 }
 
 func (s *Store) Save(r *http.Request, w http.ResponseWriter, session *sessions.Session) error {
-	if session.Options.MaxAge <= 0 {
+	if session.Options.MaxAge < 0 {
 		if err := s.delete(r.Context(), session); err != nil {
 			return errors.WithStack(err)
 		}
@@ -120,7 +123,12 @@ func (s *Store) save(ctx context.Context, session *sessions.Session) error {
 		return errors.WithStack(err)
 	}
 
-	if err := s.adapter.Set(ctx, s.keyPrefix+session.ID, b, time.Duration(session.Options.MaxAge)*time.Second); err != nil {
+	ttl := time.Duration(session.Options.MaxAge) * time.Second
+	if s.ttl < ttl || ttl == 0 {
+		ttl = s.ttl
+	}
+
+	if err := s.adapter.Set(ctx, s.keyPrefix+session.ID, b, ttl); err != nil {
 		return errors.WithStack(err)
 	}
 

misc/packaging/common/config.yml

@@ -218,6 +218,11 @@ layers:
   authn:
     # Répertoire contenant les templates
     templateDir: "/etc/bouncer/layers/authn/templates"
+    # Configuration des sessions
+    sessions:
+      # Temps de persistence sans actualisation des sessions dans le store
+      # (prévalent sur le MaxAge de la session)
+      ttl: "1h"
 
 # Configuration d'une série de proxy/layers
 # à créer par défaut par le serveur d'administration