Merge pull request #14 from pusher/oidc

OIDC ID Token, Authorization Headers, Refreshing and Verification

CHANGELOG.md

@@ -2,6 +2,11 @@
 
 ## Changes since v3.0.0
 
+- [#14](https://github.com/pusher/oauth2_proxy/pull/14) OIDC ID Token, Authorization Headers, Refreshing and Verification (@joelspeed)
+  - Implement `pass-authorization-header` and `set-authorization-header` flags
+  - Implement token refreshing in OIDC provider
+  - Split cookies larger than 4k limit into multiple cookies
+  - Implement token validation in OIDC provider
 - [#21](https://github.com/pusher/oauth2_proxy/pull/21) Docker Improvement (@yaegashi)
   - Move Docker base image from debian to alpine
   - Install ca-certificates in docker image

README.md

@@ -212,6 +212,7 @@ Usage of oauth2_proxy:
   -https-address string: <addr>:<port> to listen on for HTTPS clients (default ":443")
   -login-url string: Authentication endpoint
   -pass-access-token: pass OAuth access_token to upstream via X-Forwarded-Access-Token header
+  -pass-authorization-header: pass OIDC IDToken to upstream via Authorization Bearer header
   -pass-basic-auth: pass HTTP Basic Auth, X-Forwarded-User and X-Forwarded-Email information to upstream (default true)
   -pass-host-header: pass the request Host Header to upstream (default true)
   -pass-user-headers: pass X-Forwarded-User and X-Forwarded-Email information to upstream (default true)
@@ -225,6 +226,7 @@ Usage of oauth2_proxy:
   -resource string: The resource that is protected (Azure AD only)
   -scope string: OAuth scope specification
   -set-xauthrequest: set X-Auth-Request-User and X-Auth-Request-Email response headers (useful in Nginx auth_request mode)
+  -set-authorization-header: set Authorization Bearer response header (useful in Nginx auth_request mode)
   -signature-key string: GAP-Signature request signature key (algorithm:secretkey)
   -skip-auth-preflight: will skip authentication for OPTIONS requests
   -skip-auth-regex value: bypass authentication for requests path's that match (may be given multiple times)

main.go

@@ -37,6 +37,8 @@ func main() {
 	flagSet.String("basic-auth-password", "", "the password to set when passing the HTTP Basic Auth header")
 	flagSet.Bool("pass-access-token", false, "pass OAuth access_token to upstream via X-Forwarded-Access-Token header")
 	flagSet.Bool("pass-host-header", true, "pass the request Host Header to upstream")
+	flagSet.Bool("pass-authorization-header", false, "pass the Authorization Header to upstream")
+	flagSet.Bool("set-authorization-header", false, "set Authorization response headers (useful in Nginx auth_request mode)")
 	flagSet.Var(&skipAuthRegex, "skip-auth-regex", "bypass authentication for requests path's that match (may be given multiple times)")
 	flagSet.Bool("skip-provider-button", false, "will skip sign-in-page to directly reach the next step: oauth/start")
 	flagSet.Bool("skip-auth-preflight", false, "will skip authentication for OPTIONS requests")

oauthproxy.go

@@ -26,6 +26,10 @@ const (
 
 	httpScheme  = "http"
 	httpsScheme = "https"
+
+	// Cookies are limited to 4kb including the length of the cookie name,
+	// the cookie name can be up to 256 bytes
+	maxCookieLength = 3840
 )
 
 // SignatureHeaders contains the headers to be signed by the hmac algorithm
@@ -76,6 +80,8 @@ type OAuthProxy struct {
 	PassUserHeaders     bool
 	BasicAuthPassword   string
 	PassAccessToken     bool
+	SetAuthorization    bool
+	PassAuthorization   bool
 	CookieCipher        *cookie.Cipher
 	skipAuthRegex       []string
 	skipAuthPreflight   bool
@@ -183,7 +189,7 @@ func NewOAuthProxy(opts *Options, validator func(string) bool) *OAuthProxy {
 	log.Printf("Cookie settings: name:%s secure(https):%v httponly:%v expiry:%s domain:%s refresh:%s", opts.CookieName, opts.CookieSecure, opts.CookieHTTPOnly, opts.CookieExpire, opts.CookieDomain, refresh)
 
 	var cipher *cookie.Cipher
-	if opts.PassAccessToken || (opts.CookieRefresh != time.Duration(0)) {
+	if opts.PassAccessToken || opts.SetAuthorization || opts.PassAuthorization || (opts.CookieRefresh != time.Duration(0)) {
 		var err error
 		cipher, err = cookie.NewCipher(secretBytes(opts.CookieSecret))
 		if err != nil {
@@ -222,6 +228,8 @@ func NewOAuthProxy(opts *Options, validator func(string) bool) *OAuthProxy {
 		PassUserHeaders:    opts.PassUserHeaders,
 		BasicAuthPassword:  opts.BasicAuthPassword,
 		PassAccessToken:    opts.PassAccessToken,
+		SetAuthorization:   opts.SetAuthorization,
+		PassAuthorization:  opts.PassAuthorization,
 		SkipProviderButton: opts.SkipProviderButton,
 		CookieCipher:       cipher,
 		templates:          loadTemplates(opts.CustomTemplatesDir),
@@ -278,15 +286,100 @@ func (p *OAuthProxy) redeemCode(host, code string) (s *providers.SessionState, e
 
 // MakeSessionCookie creates an http.Cookie containing the authenticated user's
 // authentication details
-func (p *OAuthProxy) MakeSessionCookie(req *http.Request, value string, expiration time.Duration, now time.Time) *http.Cookie {
+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
+	c := p.makeCookie(req, p.CookieName, value, expiration, now)
-			log.Printf("WARNING - Cookie Size: %d bytes", len(value))
+	if len(c.Value) > 4096-len(p.CookieName) {
+		return splitCookie(c)
+	}
+	return []*http.Cookie{c}
+}
+
+func copyCookie(c *http.Cookie) *http.Cookie {
+	return &http.Cookie{
+		Name:       c.Name,
+		Value:      c.Value,
+		Path:       c.Path,
+		Domain:     c.Domain,
+		Expires:    c.Expires,
+		RawExpires: c.RawExpires,
+		MaxAge:     c.MaxAge,
+		Secure:     c.Secure,
+		HttpOnly:   c.HttpOnly,
+		Raw:        c.Raw,
+		Unparsed:   c.Unparsed,
+	}
+}
+
+// splitCookie reads the full cookie generated to store the session and splits
+// it into a slice of cookies which fit within the 4kb cookie limit indexing
+// the cookies from 0
+func splitCookie(c *http.Cookie) []*http.Cookie {
+	if len(c.Value) < maxCookieLength {
+		return []*http.Cookie{c}
+	}
+	cookies := []*http.Cookie{}
+	valueBytes := []byte(c.Value)
+	count := 0
+	for len(valueBytes) > 0 {
+		new := copyCookie(c)
+		new.Name = fmt.Sprintf("%s-%d", c.Name, count)
+		count++
+		if len(valueBytes) < maxCookieLength {
+			new.Value = string(valueBytes)
+			valueBytes = []byte{}
+		} else {
+			newValue := valueBytes[:maxCookieLength]
+			valueBytes = valueBytes[maxCookieLength:]
+			new.Value = string(newValue)
+		}
+		cookies = append(cookies, new)
+	}
+	return cookies
+}
+
+// joinCookies takes a slice of cookies from the request and reconstructs the
+// full session cookie
+func joinCookies(cookies []*http.Cookie) (*http.Cookie, error) {
+	if len(cookies) == 0 {
+		return nil, fmt.Errorf("list of cookies must be > 0")
+	}
+	if len(cookies) == 1 {
+		return cookies[0], nil
+	}
+	c := copyCookie(cookies[0])
+	for i := 1; i < len(cookies); i++ {
+		c.Value += cookies[i].Value
+	}
+	c.Name = strings.TrimRight(c.Name, "-0")
+	return c, nil
+}
+
+// loadCookie retreieves the sessions state cookie from the http request.
+// If a single cookie is present this will be returned, otherwise it attempts
+// to reconstruct a cookie split up by splitCookie
+func loadCookie(req *http.Request, cookieName string) (*http.Cookie, error) {
+	c, err := req.Cookie(cookieName)
+	if err == nil {
+		return c, nil
+	}
+	cookies := []*http.Cookie{}
+	err = nil
+	count := 0
+	for err == nil {
+		var c *http.Cookie
+		c, err = req.Cookie(fmt.Sprintf("%s-%d", cookieName, count))
+		if err == nil {
+			cookies = append(cookies, c)
+			count++
 		}
 	}
-	return p.makeCookie(req, p.CookieName, value, expiration, now)
+	if len(cookies) == 0 {
+		return nil, fmt.Errorf("Could not find cookie %s", cookieName)
+	}
+	return joinCookies(cookies)
 }
 
 // MakeCSRFCookie creates a cookie for CSRF
@@ -330,12 +423,14 @@ func (p *OAuthProxy) SetCSRFCookie(rw http.ResponseWriter, req *http.Request, va
 // ClearSessionCookie creates a cookie to unset the user's authentication cookie
 // stored in the user's session
 func (p *OAuthProxy) ClearSessionCookie(rw http.ResponseWriter, req *http.Request) {
-	clr := p.MakeSessionCookie(req, "", time.Hour*-1, time.Now())
+	cookies := p.MakeSessionCookie(req, "", time.Hour*-1, time.Now())
-	http.SetCookie(rw, clr)
+	for _, clr := range cookies {
+		http.SetCookie(rw, clr)
+	}
 
 	// ugly hack because default domain changed
-	if p.CookieDomain == "" {
+	if p.CookieDomain == "" && len(cookies) > 0 {
-		clr2 := *clr
+		clr2 := *cookies[0]
 		clr2.Domain = req.Host
 		http.SetCookie(rw, &clr2)
 	}
@@ -343,13 +438,15 @@ func (p *OAuthProxy) ClearSessionCookie(rw http.ResponseWriter, req *http.Reques
 
 // SetSessionCookie adds the user's session cookie to the response
 func (p *OAuthProxy) SetSessionCookie(rw http.ResponseWriter, req *http.Request, val string) {
-	http.SetCookie(rw, p.MakeSessionCookie(req, val, p.CookieExpire, time.Now()))
+	for _, c := range p.MakeSessionCookie(req, val, p.CookieExpire, time.Now()) {
+		http.SetCookie(rw, c)
+	}
 }
 
 // LoadCookiedSession reads the user's authentication details from the request
 func (p *OAuthProxy) LoadCookiedSession(req *http.Request) (*providers.SessionState, time.Duration, error) {
 	var age time.Duration
-	c, err := req.Cookie(p.CookieName)
+	c, err := loadCookie(req, p.CookieName)
 	if err != nil {
 		// always http.ErrNoCookie
 		return nil, age, fmt.Errorf("Cookie %q not present", p.CookieName)
@@ -750,6 +847,12 @@ func (p *OAuthProxy) Authenticate(rw http.ResponseWriter, req *http.Request) int
 	if p.PassAccessToken && session.AccessToken != "" {
 		req.Header["X-Forwarded-Access-Token"] = []string{session.AccessToken}
 	}
+	if p.PassAuthorization && session.IDToken != "" {
+		req.Header["Authorization"] = []string{fmt.Sprintf("Bearer %s", session.IDToken)}
+	}
+	if p.SetAuthorization && session.IDToken != "" {
+		rw.Header().Set("Authorization", fmt.Sprintf("Bearer %s", session.IDToken))
+	}
 	if session.Email == "" {
 		rw.Header().Set("GAP-Auth", session.User)
 	} else {

oauthproxy_test.go

@@ -502,7 +502,7 @@ func NewProcessCookieTestWithDefaults() *ProcessCookieTest {
 	})
 }
 
-func (p *ProcessCookieTest) MakeCookie(value string, ref time.Time) *http.Cookie {
+func (p *ProcessCookieTest) MakeCookie(value string, ref time.Time) []*http.Cookie {
 	return p.proxy.MakeSessionCookie(p.req, value, p.opts.CookieExpire, ref)
 }
 
@@ -511,7 +511,9 @@ func (p *ProcessCookieTest) SaveSession(s *providers.SessionState, ref time.Time
 	if err != nil {
 		return err
 	}
-	p.req.AddCookie(p.proxy.MakeSessionCookie(p.req, value, p.proxy.CookieExpire, ref))
+	for _, c := range p.proxy.MakeSessionCookie(p.req, value, p.proxy.CookieExpire, ref) {
+		p.req.AddCookie(c)
+	}
 	return nil
 }
 
@@ -800,8 +802,9 @@ func (st *SignatureTest) MakeRequestWithExpectedKey(method, body, key string) {
 	if err != nil {
 		panic(err)
 	}
-	cookie := proxy.MakeSessionCookie(req, value, proxy.CookieExpire, time.Now())
+	for _, c := range proxy.MakeSessionCookie(req, value, proxy.CookieExpire, time.Now()) {
-	req.AddCookie(cookie)
+		req.AddCookie(c)
+	}
 	// This is used by the upstream to validate the signature.
 	st.authenticator.auth = hmacauth.NewHmacAuth(
 		crypto.SHA1, []byte(key), SignatureHeader, SignatureHeaders)

options.go

@@ -61,6 +61,8 @@ type Options struct {
 	PassUserHeaders       bool     `flag:"pass-user-headers" cfg:"pass_user_headers"`
 	SSLInsecureSkipVerify bool     `flag:"ssl-insecure-skip-verify" cfg:"ssl_insecure_skip_verify"`
 	SetXAuthRequest       bool     `flag:"set-xauthrequest" cfg:"set_xauthrequest"`
+	SetAuthorization      bool     `flag:"set-authorization-header" cfg:"set_authorization_header"`
+	PassAuthorization     bool     `flag:"pass-authorization-header" cfg:"pass_authorization_header"`
 	SkipAuthPreflight     bool     `flag:"skip-auth-preflight" cfg:"skip_auth_preflight"`
 
 	// These options allow for other providers besides Google, with
@@ -113,6 +115,8 @@ func NewOptions() *Options {
 		PassUserHeaders:      true,
 		PassAccessToken:      false,
 		PassHostHeader:       true,
+		SetAuthorization:     false,
+		PassAuthorization:    false,
 		ApprovalPrompt:       "force",
 		RequestLogging:       true,
 		RequestLoggingFormat: defaultRequestLoggingFormat,

providers/google.go

@@ -145,6 +145,7 @@ func (p *GoogleProvider) Redeem(redirectURL, code string) (s *SessionState, err
 	}
 	s = &SessionState{
 		AccessToken:  jsonResponse.AccessToken,
+		IDToken:      jsonResponse.IDToken,
 		ExpiresOn:    time.Now().Add(time.Duration(jsonResponse.ExpiresIn) * time.Second).Truncate(time.Second),
 		RefreshToken: jsonResponse.RefreshToken,
 		Email:        email,

providers/oidc.go

@@ -38,7 +38,61 @@ 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(ctx, token)
+	if err != nil {
+		return nil, fmt.Errorf("unable to update session: %v", err)
+	}
+	return
+}
 
+// RefreshSessionIfNeeded checks if the session has expired and uses the
+// RefreshToken to fetch a new ID token if required
+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(ctx, token)
+	if err != nil {
+		return fmt.Errorf("unable to update session: %v", err)
+	}
+	s.AccessToken = newSession.AccessToken
+	s.IDToken = newSession.IDToken
+	s.RefreshToken = newSession.RefreshToken
+	s.ExpiresOn = newSession.ExpiresOn
+	s.Email = newSession.Email
+	return
+}
+
+func (p *OIDCProvider) createSessionState(ctx context.Context, token *oauth2.Token) (*SessionState, error) {
 	rawIDToken, ok := token.Extra("id_token").(string)
 	if !ok {
 		return nil, fmt.Errorf("token response did not contain an id_token")
@@ -66,28 +120,22 @@ 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,
+		IDToken:      rawIDToken,
 		RefreshToken: token.RefreshToken,
 		ExpiresOn:    token.Expiry,
 		Email:        claims.Email,
-	}
+	}, nil
-
-	return
 }
 
-// RefreshSessionIfNeeded checks if the session has expired and uses the
+// ValidateSessionState checks that the session's IDToken is still valid
-// RefreshToken to fetch a new ID token if required
+func (p *OIDCProvider) ValidateSessionState(s *SessionState) bool {
-//
+	ctx := context.Background()
-// WARNGING: This implementation is broken and does not check with the upstream
+	_, err := p.Verifier.Verify(ctx, s.IDToken)
-// OIDC provider before refreshing the session
+	if err != nil {
-func (p *OIDCProvider) RefreshSessionIfNeeded(s *SessionState) (bool, error) {
+		return false
-	if s == nil || s.ExpiresOn.After(time.Now()) || s.RefreshToken == "" {
-		return false, nil
 	}
 
-	origExpiration := s.ExpiresOn
+	return true
-	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
 }

providers/session_state.go

@@ -12,6 +12,7 @@ import (
 // SessionState is used to store information about the currently authenticated user session
 type SessionState struct {
 	AccessToken  string
+	IDToken      string
 	ExpiresOn    time.Time
 	RefreshToken string
 	Email        string
@@ -32,6 +33,9 @@ func (s *SessionState) String() string {
 	if s.AccessToken != "" {
 		o += " token:true"
 	}
+	if s.IDToken != "" {
+		o += " id_token:true"
+	}
 	if !s.ExpiresOn.IsZero() {
 		o += fmt.Sprintf(" expires:%s", s.ExpiresOn)
 	}
@@ -65,13 +69,19 @@ func (s *SessionState) EncryptedString(c *cookie.Cipher) (string, error) {
 			return "", err
 		}
 	}
+	i := s.IDToken
+	if i != "" {
+		if i, err = c.Encrypt(i); err != nil {
+			return "", err
+		}
+	}
 	r := s.RefreshToken
 	if r != "" {
 		if r, err = c.Encrypt(r); err != nil {
 			return "", err
 		}
 	}
-	return fmt.Sprintf("%s|%s|%d|%s", s.accountInfo(), a, s.ExpiresOn.Unix(), r), nil
+	return fmt.Sprintf("%s|%s|%s|%d|%s", s.accountInfo(), a, i, s.ExpiresOn.Unix(), r), nil
 }
 
 func decodeSessionStatePlain(v string) (s *SessionState, err error) {
@@ -96,8 +106,8 @@ func DecodeSessionState(v string, c *cookie.Cipher) (s *SessionState, err error)
 	}
 
 	chunks := strings.Split(v, "|")
-	if len(chunks) != 4 {
+	if len(chunks) != 5 {
-		err = fmt.Errorf("invalid number of fields (got %d expected 4)", len(chunks))
+		err = fmt.Errorf("invalid number of fields (got %d expected 5)", len(chunks))
 		return
 	}
 
@@ -112,11 +122,17 @@ func DecodeSessionState(v string, c *cookie.Cipher) (s *SessionState, err error)
 		}
 	}
 
-	ts, _ := strconv.Atoi(chunks[2])
+	if chunks[2] != "" {
+		if sessionState.IDToken, err = c.Decrypt(chunks[2]); err != nil {
+			return nil, err
+		}
+	}
+
+	ts, _ := strconv.Atoi(chunks[3])
 	sessionState.ExpiresOn = time.Unix(int64(ts), 0)
 
-	if chunks[3] != "" {
+	if chunks[4] != "" {
-		if sessionState.RefreshToken, err = c.Decrypt(chunks[3]); err != nil {
+		if sessionState.RefreshToken, err = c.Decrypt(chunks[4]); err != nil {
 			return nil, err
 		}
 	}

providers/session_state_test.go

@@ -21,12 +21,13 @@ func TestSessionStateSerialization(t *testing.T) {
 	s := &SessionState{
 		Email:        "user@domain.com",
 		AccessToken:  "token1234",
+		IDToken:      "rawtoken1234",
 		ExpiresOn:    time.Now().Add(time.Duration(1) * time.Hour),
 		RefreshToken: "refresh4321",
 	}
 	encoded, err := s.EncodeSessionState(c)
 	assert.Equal(t, nil, err)
-	assert.Equal(t, 3, strings.Count(encoded, "|"))
+	assert.Equal(t, 4, strings.Count(encoded, "|"))
 
 	ss, err := DecodeSessionState(encoded, c)
 	t.Logf("%#v", ss)
@@ -34,6 +35,7 @@ func TestSessionStateSerialization(t *testing.T) {
 	assert.Equal(t, "user", ss.User)
 	assert.Equal(t, s.Email, ss.Email)
 	assert.Equal(t, s.AccessToken, ss.AccessToken)
+	assert.Equal(t, s.IDToken, ss.IDToken)
 	assert.Equal(t, s.ExpiresOn.Unix(), ss.ExpiresOn.Unix())
 	assert.Equal(t, s.RefreshToken, ss.RefreshToken)
 
@@ -45,6 +47,7 @@ func TestSessionStateSerialization(t *testing.T) {
 	assert.Equal(t, s.Email, ss.Email)
 	assert.Equal(t, s.ExpiresOn.Unix(), ss.ExpiresOn.Unix())
 	assert.NotEqual(t, s.AccessToken, ss.AccessToken)
+	assert.NotEqual(t, s.IDToken, ss.IDToken)
 	assert.NotEqual(t, s.RefreshToken, ss.RefreshToken)
 }
 
@@ -62,7 +65,7 @@ func TestSessionStateSerializationWithUser(t *testing.T) {
 	}
 	encoded, err := s.EncodeSessionState(c)
 	assert.Equal(t, nil, err)
-	assert.Equal(t, 3, strings.Count(encoded, "|"))
+	assert.Equal(t, 4, strings.Count(encoded, "|"))
 
 	ss, err := DecodeSessionState(encoded, c)
 	t.Logf("%#v", ss)