Implement refreshing within OIDC provider

README.md

@@ -191,6 +191,10 @@ OpenID Connect is a spec for OAUTH 2.0 + identity that is implemented by many ma
     -cookie-secure=false
     -email-domain example.com
 
+If you enable cookie-refresh, it should be set to the same duration as token lifetime
+(due to a limitation in `oauth2_proxy` - see [bitly/oauth2_proxy#620](https://github.com/bitly/oauth2_proxy/pull/620)).
+
+
 ## Email Authentication
 
 To authorize by email domain use `--email-domain=yourcompany.com`. To authorize individual email addresses use `--authenticated-emails-file=/path/to/file` with one email per line. To authorize all email addresses use `--email-domain=*`.

oauthproxy.go

@@ -259,10 +259,6 @@ func (p *OAuthProxy) redeemCode(host, code string) (s *providers.SessionState, e
 func (p *OAuthProxy) MakeSessionCookie(req *http.Request, value string, expiration time.Duration, now time.Time) *http.Cookie {
 	if value != "" {
 		value = cookie.SignedValue(p.CookieSeed, p.CookieName, value, now)
-		if len(value) > 4096 {
-			// Cookies cannot be larger than 4kb
-			log.Printf("WARNING - Cookie Size: %d bytes", len(value))
-		}
 	}
 	return p.makeCookie(req, p.CookieName, value, expiration, now)
 }
@@ -281,6 +277,11 @@ func (p *OAuthProxy) makeCookie(req *http.Request, name string, value string, ex
 			log.Printf("Warning: request host is %q but using configured cookie domain of %q", domain, p.CookieDomain)
 		}
 	}
+	if len(value) > 3600 {
+		// nginx default response header limit is 4KiB, other software may have similar limits
+		// threshold includes margin for header name, cookie name, other cookie options
+		log.Printf("WARNING - %s cookie is very big: %d bytes", name, len(value))
+	}
 
 	return &http.Cookie{
 		Name:     name,

providers/oidc.go

@@ -35,7 +35,58 @@ func (p *OIDCProvider) Redeem(redirectURL, code string) (s *SessionState, err er
 	if err != nil {
 		return nil, fmt.Errorf("token exchange: %v", err)
 	}
+	s, err = p.createSessionState(token, ctx)
+	if err != nil {
+		return nil, fmt.Errorf("unable to update session: %v", err)
+	}
+	return
+}
+
+func (p *OIDCProvider) RefreshSessionIfNeeded(s *SessionState) (bool, error) {
+	if s == nil || s.ExpiresOn.After(time.Now()) || s.RefreshToken == "" {
+		return false, nil
+	}
+
+	origExpiration := s.ExpiresOn
 
+	err := p.redeemRefreshToken(s)
+	if err != nil {
+		return false, fmt.Errorf("unable to redeem refresh token: %v", err)
+	}
+
+	fmt.Printf("refreshed id token %s (expired on %s)\n", s, origExpiration)
+	return true, nil
+}
+
+func (p *OIDCProvider) redeemRefreshToken(s *SessionState) (err error) {
+	c := oauth2.Config{
+		ClientID:     p.ClientID,
+		ClientSecret: p.ClientSecret,
+		Endpoint: oauth2.Endpoint{
+			TokenURL: p.RedeemURL.String(),
+		},
+	}
+	ctx := context.Background()
+	t := &oauth2.Token{
+		RefreshToken: s.RefreshToken,
+		Expiry:       time.Now().Add(-time.Hour),
+	}
+	token, err := c.TokenSource(ctx, t).Token()
+	if err != nil {
+		return fmt.Errorf("failed to get token: %v", err)
+	}
+	newSession, err := p.createSessionState(token, ctx)
+	if err != nil {
+		return fmt.Errorf("unable to update session: %v", err)
+	}
+	s.AccessToken = newSession.AccessToken
+	s.RefreshToken = newSession.RefreshToken
+	s.ExpiresOn = newSession.ExpiresOn
+	s.Email = newSession.Email
+	return
+}
+
+func (p *OIDCProvider) createSessionState(token *oauth2.Token, ctx context.Context) (*SessionState, error) {
 	rawIDToken, ok := token.Extra("id_token").(string)
 	if !ok {
 		return nil, fmt.Errorf("token response did not contain an id_token")
@@ -63,23 +114,10 @@ func (p *OIDCProvider) Redeem(redirectURL, code string) (s *SessionState, err er
 		return nil, fmt.Errorf("email in id_token (%s) isn't verified", claims.Email)
 	}
 
-	s = &SessionState{
+	return &SessionState{
 		AccessToken:  token.AccessToken,
 		RefreshToken: token.RefreshToken,
 		ExpiresOn:    token.Expiry,
 		Email:        claims.Email,
-	}
-
-	return
-}
-
-func (p *OIDCProvider) RefreshSessionIfNeeded(s *SessionState) (bool, error) {
-	if s == nil || s.ExpiresOn.After(time.Now()) || s.RefreshToken == "" {
-		return false, nil
-	}
-
-	origExpiration := s.ExpiresOn
-	s.ExpiresOn = time.Now().Add(time.Second).Truncate(time.Second)
-	fmt.Printf("refreshed access token %s (expired on %s)\n", s, origExpiration)
-	return false, nil
+	}, nil
 }