Add option to remove tokens from cookie sessions (#673)

* Add option to remove tokens from cookie sessions

* Move Minimal to be an option on CookieSession

* Add sessionOptionsDefaults helper

CHANGELOG.md

@@ -11,6 +11,7 @@
 
 ## Changes since v6.0.0
 
+- [#673](https://github.com/oauth2-proxy/oauth2-proxy/pull/673) Add --session-cookie-minimal option to create session cookies with no tokens (@NickMeves)
 - [#632](https://github.com/oauth2-proxy/oauth2-proxy/pull/632) Reduce session size by encoding with MessagePack and using LZ4 compression (@NickMeves)
 - [#675](https://github.com/oauth2-proxy/oauth2-proxy/pull/675) Fix required ruby version and deprecated option for building docs (@mkontani)
 - [#669](https://github.com/oauth2-proxy/oauth2-proxy/pull/669) Reduce docker context to improve build times (@JoelSpeed)

docs/configuration/configuration.md

@@ -107,6 +107,7 @@ An example [oauth2-proxy.cfg]({{ site.gitweb }}/contrib/oauth2-proxy.cfg.example
 | `--resource` | string | The resource that is protected (Azure AD only) | |
 | `--reverse-proxy` | bool | are we running behind a reverse proxy, controls whether headers like X-Real-Ip are accepted | false |
 | `--scope` | string | OAuth scope specification | |
+| `--session-cookie-minimal` | bool | strip OAuth tokens from cookie session stores if they aren't needed (cookie session store only) | false |
 | `--session-store-type` | string | [Session data storage backend](configuration/sessions); redis or cookie | cookie |
 | `--set-xauthrequest` | bool | set X-Auth-Request-User, X-Auth-Request-Email and X-Auth-Request-Preferred-Username response headers (useful in Nginx auth_request mode) | false |
 | `--set-authorization-header` | bool | set Authorization Bearer response header (useful in Nginx auth_request mode) | false |

pkg/apis/options/options.go

@@ -155,9 +155,7 @@ func NewOptions() *Options {
 		ForceHTTPS:                       false,
 		DisplayHtpasswdForm:              true,
 		Cookie:                           cookieDefaults(),
-		Session: SessionOptions{
-			Type: "cookie",
-		},
+		Session:                          sessionOptionsDefaults(),
 		AzureTenant:                      "common",
 		SetXAuthRequest:                  false,
 		SkipAuthPreflight:                false,
@@ -241,6 +239,7 @@ func NewFlagSet() *pflag.FlagSet {
 	flagSet.String("ping-user-agent", "", "special User-Agent that will be used for basic health checks")
 	flagSet.Bool("proxy-websockets", true, "enables WebSocket proxying")
 	flagSet.String("session-store-type", "cookie", "the session storage provider to use")
+	flagSet.Bool("session-cookie-minimal", false, "strip OAuth tokens from cookie session stores if they aren't needed (cookie session store only)")
 	flagSet.String("redis-connection-url", "", "URL of redis server for redis session storage (eg: redis://HOST[:PORT])")
 	flagSet.Bool("redis-use-sentinel", false, "Connect to redis via sentinels. Must set --redis-sentinel-master-name and --redis-sentinel-connection-urls to use this feature")
 	flagSet.String("redis-sentinel-master-name", "", "Redis sentinel master name. Used in conjunction with --redis-use-sentinel")

pkg/apis/options/sessions.go

@@ -3,6 +3,7 @@ package options
 // SessionOptions contains configuration options for the SessionStore providers.
 type SessionOptions struct {
 	Type   string             `flag:"session-store-type" cfg:"session_store_type"`
+	Cookie CookieStoreOptions `cfg:",squash"`
 	Redis  RedisStoreOptions  `cfg:",squash"`
 }
 
@@ -14,6 +15,11 @@ var CookieSessionStoreType = "cookie"
 // used for storing sessions.
 var RedisSessionStoreType = "redis"
 
+// CookieStoreOptions contains configuration options for the CookieSessionStore.
+type CookieStoreOptions struct {
+	Minimal bool `flag:"session-cookie-minimal" cfg:"session_cookie_minimal"`
+}
+
 // RedisStoreOptions contains configuration options for the RedisSessionStore.
 type RedisStoreOptions struct {
 	ConnectionURL          string   `flag:"redis-connection-url" cfg:"redis_connection_url"`
@@ -25,3 +31,12 @@ type RedisStoreOptions struct {
 	CAPath                 string   `flag:"redis-ca-path" cfg:"redis_ca_path"`
 	InsecureSkipTLSVerify  bool     `flag:"redis-insecure-skip-tls-verify" cfg:"redis_insecure_skip_tls_verify"`
 }
+
+func sessionOptionsDefaults() SessionOptions {
+	return SessionOptions{
+		Type: CookieSessionStoreType,
+		Cookie: CookieStoreOptions{
+			Minimal: false,
+		},
+	}
+}

pkg/sessions/cookie/session_store.go

@@ -30,6 +30,7 @@ var _ sessions.SessionStore = &SessionStore{}
 type SessionStore struct {
 	Cookie       *options.Cookie
 	CookieCipher encryption.Cipher
+	Minimal      bool
 }
 
 // Save takes a sessions.SessionState and stores the information from it
@@ -39,7 +40,7 @@ func (s *SessionStore) Save(rw http.ResponseWriter, req *http.Request, ss *sessi
 		now := time.Now()
 		ss.CreatedAt = &now
 	}
-	value, err := cookieForSession(ss, s.CookieCipher)
+	value, err := s.cookieForSession(ss)
 	if err != nil {
 		return err
 	}
@@ -85,8 +86,17 @@ func (s *SessionStore) Clear(rw http.ResponseWriter, req *http.Request) error {
 }
 
 // cookieForSession serializes a session state for storage in a cookie
-func cookieForSession(s *sessions.SessionState, c encryption.Cipher) ([]byte, error) {
-	return s.EncodeSessionState(c, true)
+func (s *SessionStore) cookieForSession(ss *sessions.SessionState) ([]byte, error) {
+	if s.Minimal && (ss.AccessToken != "" || ss.IDToken != "" || ss.RefreshToken != "") {
+		minimal := *ss
+		minimal.AccessToken = ""
+		minimal.IDToken = ""
+		minimal.RefreshToken = ""
+
+		return minimal.EncodeSessionState(s.CookieCipher, true)
+	}
+
+	return ss.EncodeSessionState(s.CookieCipher, true)
 }
 
 // sessionFromCookie deserializes a session from a cookie value
@@ -146,6 +156,7 @@ func NewCookieSessionStore(opts *options.SessionOptions, cookieOpts *options.Coo
 	return &SessionStore{
 		CookieCipher: cipher,
 		Cookie:       cookieOpts,
+		Minimal:      opts.Cookie.Minimal,
 	}, nil
 }
 

pkg/validation/options.go

@@ -27,6 +27,7 @@ import (
 // are of the correct format
 func Validate(o *options.Options) error {
 	msgs := validateCookie(o.Cookie)
+	msgs = append(msgs, validateSessionCookieMinimal(o)...)
 
 	if o.SSLInsecureSkipVerify {
 		insecureTransport := &http.Transport{

pkg/validation/sessions.go

@@ -0,0 +1,32 @@
+package validation
+
+import (
+	"time"
+
+	"github.com/oauth2-proxy/oauth2-proxy/pkg/apis/options"
+)
+
+func validateSessionCookieMinimal(o *options.Options) []string {
+	if !o.Session.Cookie.Minimal {
+		return []string{}
+	}
+
+	msgs := []string{}
+	if o.PassAuthorization {
+		msgs = append(msgs,
+			"pass_authorization_header requires oauth tokens in sessions. session_cookie_minimal cannot be set")
+	}
+	if o.SetAuthorization {
+		msgs = append(msgs,
+			"set_authorization_header requires oauth tokens in sessions. session_cookie_minimal cannot be set")
+	}
+	if o.PassAccessToken {
+		msgs = append(msgs,
+			"pass_access_token requires oauth tokens in sessions. session_cookie_minimal cannot be set")
+	}
+	if o.Cookie.Refresh != time.Duration(0) {
+		msgs = append(msgs,
+			"cookie_refresh > 0 requires oauth tokens in sessions. session_cookie_minimal cannot be set")
+	}
+	return msgs
+}

pkg/validation/sessions_test.go

@@ -0,0 +1,121 @@
+package validation
+
+import (
+	"testing"
+	"time"
+
+	"github.com/oauth2-proxy/oauth2-proxy/pkg/apis/options"
+	. "github.com/onsi/gomega"
+)
+
+func Test_validateSessionCookieMinimal(t *testing.T) {
+	const (
+		passAuthorizationMsg = "pass_authorization_header requires oauth tokens in sessions. session_cookie_minimal cannot be set"
+		setAuthorizationMsg  = "set_authorization_header requires oauth tokens in sessions. session_cookie_minimal cannot be set"
+		passAccessTokenMsg   = "pass_access_token requires oauth tokens in sessions. session_cookie_minimal cannot be set"
+		cookieRefreshMsg     = "cookie_refresh > 0 requires oauth tokens in sessions. session_cookie_minimal cannot be set"
+	)
+
+	testCases := map[string]struct {
+		opts       *options.Options
+		errStrings []string
+	}{
+		"No minimal cookie session": {
+			opts: &options.Options{
+				Session: options.SessionOptions{
+					Cookie: options.CookieStoreOptions{
+						Minimal: false,
+					},
+				},
+			},
+			errStrings: []string{},
+		},
+		"No minimal cookie session & passAuthorization": {
+			opts: &options.Options{
+				Session: options.SessionOptions{
+					Cookie: options.CookieStoreOptions{
+						Minimal: false,
+					},
+				},
+				PassAuthorization: true,
+			},
+			errStrings: []string{},
+		},
+		"Minimal cookie session no conflicts": {
+			opts: &options.Options{
+				Session: options.SessionOptions{
+					Cookie: options.CookieStoreOptions{
+						Minimal: true,
+					},
+				},
+			},
+			errStrings: []string{},
+		},
+		"PassAuthorization conflict": {
+			opts: &options.Options{
+				Session: options.SessionOptions{
+					Cookie: options.CookieStoreOptions{
+						Minimal: true,
+					},
+				},
+				PassAuthorization: true,
+			},
+			errStrings: []string{passAuthorizationMsg},
+		},
+		"SetAuthorization conflict": {
+			opts: &options.Options{
+				Session: options.SessionOptions{
+					Cookie: options.CookieStoreOptions{
+						Minimal: true,
+					},
+				},
+				SetAuthorization: true,
+			},
+			errStrings: []string{setAuthorizationMsg},
+		},
+		"PassAccessToken conflict": {
+			opts: &options.Options{
+				Session: options.SessionOptions{
+					Cookie: options.CookieStoreOptions{
+						Minimal: true,
+					},
+				},
+				PassAccessToken: true,
+			},
+			errStrings: []string{passAccessTokenMsg},
+		},
+		"CookieRefresh conflict": {
+			opts: &options.Options{
+				Cookie: options.Cookie{
+					Refresh: time.Hour,
+				},
+				Session: options.SessionOptions{
+					Cookie: options.CookieStoreOptions{
+						Minimal: true,
+					},
+				},
+			},
+			errStrings: []string{cookieRefreshMsg},
+		},
+		"Multiple conflicts": {
+			opts: &options.Options{
+				Session: options.SessionOptions{
+					Cookie: options.CookieStoreOptions{
+						Minimal: true,
+					},
+				},
+				PassAuthorization: true,
+				PassAccessToken:   true,
+			},
+			errStrings: []string{passAuthorizationMsg, passAccessTokenMsg},
+		},
+	}
+
+	for testName, tc := range testCases {
+		t.Run(testName, func(t *testing.T) {
+			errStrings := validateSessionCookieMinimal(tc.opts)
+			g := NewWithT(t)
+			g.Expect(errStrings).To(ConsistOf(tc.errStrings))
+		})
+	}
+}