Пример #1
0
func handleCallbackFunc(c *oidc.Client) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		code := r.URL.Query().Get("code")
		if code == "" {
			phttp.WriteError(w, http.StatusBadRequest, "code query param must be set")
			return
		}

		tok, err := c.ExchangeAuthCode(code)
		if err != nil {
			phttp.WriteError(w, http.StatusBadRequest, fmt.Sprintf("unable to verify auth code with issuer: %v", err))
			return
		}

		claims, err := tok.Claims()
		if err != nil {
			phttp.WriteError(w, http.StatusBadRequest, fmt.Sprintf("unable to construct claims: %v", err))
			return
		}

		s := fmt.Sprintf(`<html><body><p>Token: %v</p><p>Claims: %v </p>
        <a href="/resend?jwt=%s">Resend Verification Email</a>
</body></html>`, tok.Encode(), claims, tok.Encode())
		w.Write([]byte(s))
	}
}
Пример #2
0
func handleOOBFunc(s *Server, tpl *template.Template) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		if r.Method != "GET" {
			w.Header().Set("Allow", "GET")
			phttp.WriteError(w, http.StatusMethodNotAllowed, "GET only acceptable method")
			return
		}

		key := r.URL.Query().Get("code")
		if key == "" {
			phttp.WriteError(w, http.StatusBadRequest, "Invalid Session")
			return
		}
		sessionID, err := s.SessionManager.ExchangeKey(key)
		if err != nil {
			phttp.WriteError(w, http.StatusBadRequest, "Invalid Session")
			return
		}
		code, err := s.SessionManager.NewSessionKey(sessionID)
		if err != nil {
			log.Errorf("problem getting NewSessionKey: %v", err)
			phttp.WriteError(w, http.StatusInternalServerError, "Internal Server Error")
			return
		}

		execTemplate(w, tpl, map[string]string{
			"code": code,
		})
	}
}
Пример #3
0
func execTemplateWithStatus(w http.ResponseWriter, tpl Template, data interface{}, status int) {
	w.WriteHeader(status)
	if err := tpl.Execute(w, data); err != nil {
		log.Errorf("Error loading page: %q", err)
		phttp.WriteError(w, http.StatusInternalServerError, "error loading page")
		return
	}
}
Пример #4
0
func handleIndexFunc(oob bool) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		err := indexTemplate.Execute(w, map[string]interface{}{
			"OOB": oob,
		})
		if err != nil {
			phttp.WriteError(w, http.StatusInternalServerError,
				fmt.Sprintf("unable to execute template: %v", err))

		}
	}
}
Пример #5
0
func handleKeysFunc(km key.PrivateKeyManager, clock clockwork.Clock) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		if r.Method != "GET" {
			w.Header().Set("Allow", "GET")
			phttp.WriteError(w, http.StatusMethodNotAllowed, "GET only acceptable method")
			return
		}

		jwks, err := km.JWKs()
		if err != nil {
			log.Errorf("Failed to get JWKs while serving HTTP request: %v", err)
			phttp.WriteError(w, http.StatusInternalServerError, "")
			return
		}

		keys := struct {
			Keys []jose.JWK `json:"keys"`
		}{
			Keys: jwks,
		}

		b, err := json.Marshal(keys)
		if err != nil {
			log.Errorf("Unable to marshal signing key to JSON: %v", err)
		}

		exp := km.ExpiresAt()
		w.Header().Set("Expires", exp.Format(time.RFC1123))

		ttl := int(exp.Sub(clock.Now()).Seconds())
		w.Header().Set("Cache-Control", fmt.Sprintf("public, max-age=%d", ttl))

		w.Header().Set("Content-Type", "application/json")
		w.WriteHeader(http.StatusOK)
		w.Write(b)
	}
}
Пример #6
0
func handleDiscoveryFunc(cfg oidc.ProviderConfig) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		if r.Method != "GET" {
			w.Header().Set("Allow", "GET")
			phttp.WriteError(w, http.StatusMethodNotAllowed, "GET only acceptable method")
			return
		}

		b, err := json.Marshal(cfg)
		if err != nil {
			log.Errorf("Unable to marshal %#v to JSON: %v", cfg, err)
		}

		w.Header().Set("Cache-Control", fmt.Sprintf("public, max-age=%d", int(discoveryMaxAge.Seconds())))
		w.Header().Set("Content-Type", "application/json")
		w.Write(b)
	}
}
Пример #7
0
func handleLoginFunc(c *oidc.Client) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		err := r.ParseForm()
		if err != nil {
			phttp.WriteError(w, http.StatusBadRequest,
				fmt.Sprintf("Could not parse request: %v", err))
		}

		oac, err := c.OAuthClient()
		if err != nil {
			panic("unable to proceed")
		}

		u, err := url.Parse(oac.AuthCodeURL("", "", ""))
		if err != nil {
			panic("unable to proceed")
		}

		var scopes []string
		q := u.Query()
		if scope := q.Get("scope"); scope != "" {
			scopes = strings.Split(scope, " ")
		}

		if xClient := r.Form.Get("cross_client"); xClient != "" {
			xClients := strings.Split(xClient, ",")
			for _, x := range xClients {
				scopes = append(scopes, scope.ScopeGoogleCrossClient+x)
			}
		}

		if extraScopes := r.Form.Get("extra_scopes"); extraScopes != "" {
			scopes = append(scopes, strings.Split(extraScopes, ",")...)
		}

		if scopes != nil {
			q.Set("scope", strings.Join(scopes, " "))
			u.RawQuery = q.Encode()
		}

		http.Redirect(w, r, u.String(), http.StatusFound)
	}
}
Пример #8
0
func handleCallbackFunc(c *oidc.Client, claims *jose.Claims, refresh *string) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		code := r.URL.Query().Get("code")
		if code == "" {
			phttp.WriteError(w, http.StatusBadRequest, "code query param must be set")
			return
		}

		oac, err := c.OAuthClient()
		if err != nil {
			phttp.WriteError(w, http.StatusInternalServerError, fmt.Sprintf("unable to create oauth client: %v", err))
			return
		}

		t, err := oac.RequestToken(oauth2.GrantTypeAuthCode, code)
		if err != nil {
			phttp.WriteError(w, http.StatusBadRequest, fmt.Sprintf("unable to verify auth code with issuer: %v", err))
			return
		}

		// Get id token and claims.
		tok, err := jose.ParseJWT(t.IDToken)
		if err != nil {
			phttp.WriteError(w, http.StatusBadRequest, fmt.Sprintf("unable to parse id_token: %v", err))
			return
		}

		if err := c.VerifyJWT(tok); err != nil {
			phttp.WriteError(w, http.StatusBadRequest, fmt.Sprintf("unable to verify the JWT: %v", err))
			return
		}

		if *claims, err = tok.Claims(); err != nil {
			phttp.WriteError(w, http.StatusBadRequest, fmt.Sprintf("unable to construct claims: %v", err))
			return
		}

		// Get refresh token.
		*refresh = t.RefreshToken

		w.WriteHeader(http.StatusOK)
	}
}
Пример #9
0
func handleTokenFunc(srv OIDCServer) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		if r.Method != "POST" {
			w.Header().Set("Allow", "POST")
			phttp.WriteError(w, http.StatusMethodNotAllowed, fmt.Sprintf("POST only acceptable method"))
			return
		}

		err := r.ParseForm()
		if err != nil {
			log.Errorf("error parsing request: %v", err)
			writeTokenError(w, oauth2.NewError(oauth2.ErrorInvalidRequest), "")
			return
		}

		state := r.PostForm.Get("state")

		user, password, ok := r.BasicAuth()
		if !ok {
			log.Errorf("error parsing basic auth")
			writeTokenError(w, oauth2.NewError(oauth2.ErrorInvalidClient), state)
			return
		}

		creds := oidc.ClientCredentials{ID: user, Secret: password}

		var jwt *jose.JWT
		var refreshToken string
		grantType := r.PostForm.Get("grant_type")

		switch grantType {
		case oauth2.GrantTypeAuthCode:
			code := r.PostForm.Get("code")
			if code == "" {
				log.Errorf("missing code param")
				writeTokenError(w, oauth2.NewError(oauth2.ErrorInvalidRequest), state)
				return
			}
			jwt, refreshToken, err = srv.CodeToken(creds, code)
			if err != nil {
				log.Errorf("couldn't exchange code for token: %v", err)
				writeTokenError(w, err, state)
				return
			}
		case oauth2.GrantTypeClientCreds:
			jwt, err = srv.ClientCredsToken(creds)
			if err != nil {
				log.Errorf("couldn't creds for token: %v", err)
				writeTokenError(w, err, state)
				return
			}
		case oauth2.GrantTypeRefreshToken:
			token := r.PostForm.Get("refresh_token")
			if token == "" {
				writeTokenError(w, oauth2.NewError(oauth2.ErrorInvalidRequest), state)
				return
			}
			jwt, err = srv.RefreshToken(creds, token)
			if err != nil {
				writeTokenError(w, err, state)
				return
			}
		default:
			log.Errorf("unsupported grant: %v", grantType)
			writeTokenError(w, oauth2.NewError(oauth2.ErrorUnsupportedGrantType), state)
			return
		}

		t := oAuth2Token{
			AccessToken:  jwt.Encode(),
			IDToken:      jwt.Encode(),
			TokenType:    "bearer",
			RefreshToken: refreshToken,
		}

		b, err := json.Marshal(t)
		if err != nil {
			log.Errorf("Failed marshaling %#v to JSON: %v", t, err)
			writeTokenError(w, oauth2.NewError(oauth2.ErrorServerError), state)
			return
		}

		w.Header().Set("Content-Type", "application/json")
		w.WriteHeader(http.StatusOK)
		w.Write(b)
	}
}
Пример #10
0
func handleAuthFunc(srv OIDCServer, idpcs []connector.Connector, tpl *template.Template, registrationEnabled bool) http.HandlerFunc {
	idx := makeConnectorMap(idpcs)
	return func(w http.ResponseWriter, r *http.Request) {
		if r.Method != "GET" {
			w.Header().Set("Allow", "GET")
			phttp.WriteError(w, http.StatusMethodNotAllowed, "GET only acceptable method")
			return
		}

		q := r.URL.Query()
		register := q.Get("register") == "1" && registrationEnabled
		e := q.Get("error")
		if e != "" {
			sessionKey := q.Get("state")
			if err := srv.KillSession(sessionKey); err != nil {
				log.Errorf("Failed killing sessionKey %q: %v", sessionKey, err)
			}
			renderLoginPage(w, r, srv, idpcs, register, tpl)
			return
		}

		connectorID := q.Get("connector_id")
		idpc, ok := idx[connectorID]
		if !ok {
			renderLoginPage(w, r, srv, idpcs, register, tpl)
			return
		}

		acr, err := oauth2.ParseAuthCodeRequest(q)
		if err != nil {
			log.Errorf("Invalid auth request: %v", err)
			writeAuthError(w, err, acr.State)
			return
		}

		cm, err := srv.ClientMetadata(acr.ClientID)
		if err != nil {
			log.Errorf("Failed fetching client %q from repo: %v", acr.ClientID, err)
			writeAuthError(w, oauth2.NewError(oauth2.ErrorServerError), acr.State)
			return
		}
		if cm == nil {
			log.Errorf("Client %q not found", acr.ClientID)
			writeAuthError(w, oauth2.NewError(oauth2.ErrorInvalidRequest), acr.State)
			return
		}

		if len(cm.RedirectURLs) == 0 {
			log.Errorf("Client %q has no redirect URLs", acr.ClientID)
			writeAuthError(w, oauth2.NewError(oauth2.ErrorServerError), acr.State)
			return
		}

		redirectURL, err := client.ValidRedirectURL(acr.RedirectURL, cm.RedirectURLs)
		if err != nil {
			switch err {
			case (client.ErrorCantChooseRedirectURL):
				log.Errorf("Request must provide redirect URL as client %q has registered many", acr.ClientID)
				writeAuthError(w, oauth2.NewError(oauth2.ErrorInvalidRequest), acr.State)
				return
			case (client.ErrorInvalidRedirectURL):
				log.Errorf("Request provided unregistered redirect URL: %s", acr.RedirectURL)
				writeAuthError(w, oauth2.NewError(oauth2.ErrorInvalidRequest), acr.State)
				return
			case (client.ErrorNoValidRedirectURLs):
				log.Errorf("There are no registered URLs for the requested client: %s", acr.RedirectURL)
				writeAuthError(w, oauth2.NewError(oauth2.ErrorInvalidRequest), acr.State)
				return
			}
		}

		if acr.ResponseType != oauth2.ResponseTypeCode {
			log.Errorf("unexpected ResponseType: %v: ", acr.ResponseType)
			redirectAuthError(w, oauth2.NewError(oauth2.ErrorUnsupportedResponseType), acr.State, redirectURL)
			return
		}

		// Check scopes.
		var scopes []string
		foundOpenIDScope := false
		for _, scope := range acr.Scope {
			switch scope {
			case "openid":
				foundOpenIDScope = true
				scopes = append(scopes, scope)
			case "offline_access":
				// According to the spec, for offline_access scope, the client must
				// use a response_type value that would result in an Authorization Code.
				// Currently oauth2.ResponseTypeCode is the only supported response type,
				// and it's been checked above, so we don't need to check it again here.
				//
				// TODO(yifan): Verify that 'consent' should be in 'prompt'.
				scopes = append(scopes, scope)
			default:
				// Pass all other scopes.
				scopes = append(scopes, scope)
			}
		}

		if !foundOpenIDScope {
			log.Errorf("Invalid auth request: missing 'openid' in 'scope'")
			writeAuthError(w, oauth2.NewError(oauth2.ErrorInvalidRequest), acr.State)
			return
		}

		nonce := q.Get("nonce")

		key, err := srv.NewSession(connectorID, acr.ClientID, acr.State, redirectURL, nonce, register, acr.Scope)
		if err != nil {
			log.Errorf("Error creating new session: %v: ", err)
			redirectAuthError(w, err, acr.State, redirectURL)
			return
		}

		if register {
			_, ok := idpc.(*connector.LocalConnector)
			if ok {
				q := url.Values{}
				q.Set("code", key)
				ru := httpPathRegister + "?" + q.Encode()
				w.Header().Set("Location", ru)
				w.WriteHeader(http.StatusFound)
				return
			}
		}

		var p string
		if register {
			p = "select_account consent"
		}
		if shouldReprompt(r) || register {
			p = "select_account"
		}
		lu, err := idpc.LoginURL(key, p)
		if err != nil {
			log.Errorf("Connector.LoginURL failed: %v", err)
			redirectAuthError(w, err, acr.State, redirectURL)
			return
		}

		http.SetCookie(w, createLastSeenCookie())
		w.Header().Set("Location", lu)
		w.WriteHeader(http.StatusFound)
		return
	}
}
Пример #11
0
func renderLoginPage(w http.ResponseWriter, r *http.Request, srv OIDCServer, idpcs []connector.Connector, register bool, tpl *template.Template) {
	if tpl == nil {
		phttp.WriteError(w, http.StatusInternalServerError, "error loading login page")
		return
	}

	td := templateData{
		Message:                  "Error",
		Instruction:              "Please try again or contact the system administrator",
		Register:                 register,
		ShowEmailVerifiedMessage: consumeShowEmailVerifiedCookie(r, w),
	}

	// Render error if remote IdP connector errored and redirected here.
	q := r.URL.Query()
	e := q.Get("error")
	connectorID := q.Get("connector_id")
	if e != "" {
		td.Error = true
		td.Message = "Authentication Error"
		remoteMsg := q.Get("error_description")
		if remoteMsg == "" {
			remoteMsg = q.Get("error")
		}
		if connectorID == "" {
			td.Detail = remoteMsg
		} else {
			td.Detail = fmt.Sprintf("Error from %s: %s.", connectorID, remoteMsg)
		}
		execTemplate(w, tpl, td)
		return
	}

	if q.Get("msg_code") != "" {
		td.MsgCode = q.Get("msg_code")
	}

	// Render error message if client id is invalid.
	clientID := q.Get("client_id")
	cm, err := srv.ClientMetadata(clientID)
	if err != nil {
		log.Errorf("Failed fetching client %q from repo: %v", clientID, err)
		td.Error = true
		td.Message = "Server Error"
		execTemplate(w, tpl, td)
		return
	}
	if cm == nil {
		td.Error = true
		td.Message = "Authentication Error"
		td.Detail = "Invalid client ID"
		execTemplate(w, tpl, td)
		return
	}

	if len(idpcs) == 0 {
		td.Error = true
		td.Message = "Server Error"
		td.Instruction = "Unable to authenticate users at this time"
		td.Detail = "Authentication service may be misconfigured"
		execTemplate(w, tpl, td)
		return
	}

	link := *r.URL
	linkParams := link.Query()
	if !register {
		linkParams.Set("register", "1")
	} else {
		linkParams.Del("register")
	}
	linkParams.Del("msg_code")
	linkParams.Del("show_connectors")
	link.RawQuery = linkParams.Encode()
	td.RegisterOrLoginURL = link.String()

	var showConnectors map[string]struct{}

	// Only show the following connectors, if param is present
	if q.Get("show_connectors") != "" {
		conns := strings.Split(q.Get("show_connectors"), ",")
		if len(conns) != 0 {
			showConnectors = make(map[string]struct{})
			for _, connID := range conns {
				showConnectors[connID] = struct{}{}
			}
		}
	}

	for _, idpc := range idpcs {
		id := idpc.ID()
		if showConnectors != nil {
			if _, ok := showConnectors[id]; !ok {
				continue
			}
		}
		var link Link
		link.ID = id

		displayName, ok := connectorDisplayNameMap[id]
		if !ok {
			displayName = id
		}
		link.DisplayName = displayName

		v := r.URL.Query()
		v.Set("connector_id", idpc.ID())
		v.Set("response_type", "code")
		link.URL = httpPathAuth + "?" + v.Encode()
		td.Links = append(td.Links, link)
	}

	execTemplate(w, tpl, td)
}
Пример #12
0
func handleLoginFunc(lf oidc.LoginFunc, tpl *template.Template, idp *LocalIdentityProvider, localErrorPath string, errorURL url.URL) http.HandlerFunc {
	handleGET := func(w http.ResponseWriter, r *http.Request, errMsg string) {
		q := r.URL.Query()
		sessionKey := q.Get("session_key")

		p := &Page{PostURL: r.URL.String(), Name: "Local", SessionKey: sessionKey}
		if errMsg != "" {
			p.Error = true
			p.Message = errMsg
		}

		if err := tpl.Execute(w, p); err != nil {
			phttp.WriteError(w, http.StatusInternalServerError, err.Error())
		}
	}

	handlePOST := func(w http.ResponseWriter, r *http.Request) {
		if err := r.ParseForm(); err != nil {
			msg := fmt.Sprintf("unable to parse form from body: %v", err)
			phttp.WriteError(w, http.StatusBadRequest, msg)
			return
		}

		userid := r.PostForm.Get("userid")
		if userid == "" {
			handleGET(w, r, "missing email address")
			return
		}

		password := r.PostForm.Get("password")
		if password == "" {
			handleGET(w, r, "missing password")
			return
		}

		ident, err := idp.Identity(userid, password)
		log.Errorf("IDENTITY: err: %v", err)

		if ident == nil || err != nil {
			handleGET(w, r, "invalid login")
			return
		}

		q := r.URL.Query()
		sessionKey := r.FormValue("session_key")
		if sessionKey == "" {
			q.Set("error", oauth2.ErrorInvalidRequest)
			q.Set("error_description", "missing session_key")
			redirectPostError(w, errorURL, q)
			return
		}

		redirectURL, err := lf(*ident, sessionKey)
		if err != nil {
			log.Errorf("Unable to log in %#v: %v", *ident, err)
			q.Set("error", oauth2.ErrorAccessDenied)
			q.Set("error_description", "login failed")
			redirectPostError(w, errorURL, q)
			return
		}

		w.Header().Set("Location", redirectURL)
		w.WriteHeader(http.StatusFound)
	}

	return func(w http.ResponseWriter, r *http.Request) {
		switch r.Method {
		case "POST":
			handlePOST(w, r)
		case "GET":
			handleGET(w, r, "")
		default:
			w.Header().Set("Allow", "GET, POST")
			phttp.WriteError(w, http.StatusMethodNotAllowed, "GET and POST only acceptable methods")
		}
	}
}
Пример #13
0
func handleCallbackFunc(c *oidc.Client) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		refreshToken := r.URL.Query().Get("refresh_token")
		code := r.URL.Query().Get("code")

		oac, err := c.OAuthClient()
		if err != nil {
			phttp.WriteError(w, http.StatusBadRequest, fmt.Sprintf("unable to create OAuth2 client: %v", err))
			return
		}

		var token oauth2.TokenResponse

		switch {
		case code != "":
			if token, err = oac.RequestToken(oauth2.GrantTypeAuthCode, code); err != nil {
				phttp.WriteError(w, http.StatusBadRequest, fmt.Sprintf("unable to verify auth code with issuer: %v", err))
				return
			}
		case refreshToken != "":
			if token, err = oac.RequestToken(oauth2.GrantTypeRefreshToken, refreshToken); err != nil {
				phttp.WriteError(w, http.StatusBadRequest, fmt.Sprintf("unable to refresh token: %v", err))
				return
			}
			if token.RefreshToken == "" {
				token.RefreshToken = refreshToken
			}
		default:
			phttp.WriteError(w, http.StatusBadRequest, "code query param must be set")
			return
		}

		tok, err := jose.ParseJWT(token.IDToken)
		if err != nil {
			phttp.WriteError(w, http.StatusBadRequest, fmt.Sprintf("unable to parse JWT: %v", err))
			return
		}

		claims := new(bytes.Buffer)
		if err := json.Indent(claims, tok.Payload, "", "  "); err != nil {
			phttp.WriteError(w, http.StatusBadRequest, fmt.Sprintf("unable to construct claims: %v", err))
			return
		}
		s := fmt.Sprintf(`
<html>
  <head>
    <style>
/* make pre wrap */
pre {
 white-space: pre-wrap;       /* css-3 */
 white-space: -moz-pre-wrap;  /* Mozilla, since 1999 */
 white-space: -pre-wrap;      /* Opera 4-6 */
 white-space: -o-pre-wrap;    /* Opera 7 */
 word-wrap: break-word;       /* Internet Explorer 5.5+ */
} 
    </style>
  </head>
  <body>
    <p> Token: <pre><code>%v</code></pre></p>
    <p> Claims: <pre><code>%v</code></pre></p>
    <p> Refresh Token: <pre><code>%v</code></pre></p>
    <p><a href="%s?refresh_token=%s">Redeem refresh token</a><p>
    <p><a href="/resend?jwt=%s">Resend Verification Email</a></p>
  </body>
</html>`, tok.Encode(), claims.String(), token.RefreshToken, r.URL.Path, token.RefreshToken, tok.Encode())
		w.Write([]byte(s))
	}
}
Пример #14
0
func handleAuthFunc(srv OIDCServer, baseURL url.URL, idpcs []connector.Connector, tpl *template.Template, registrationEnabled bool) http.HandlerFunc {
	idx := makeConnectorMap(idpcs)
	return func(w http.ResponseWriter, r *http.Request) {
		if r.Method != "GET" {
			w.Header().Set("Allow", "GET")
			phttp.WriteError(w, http.StatusMethodNotAllowed, "GET only acceptable method")
			return
		}

		q := r.URL.Query()
		register := q.Get("register") == "1" && registrationEnabled
		e := q.Get("error")
		if e != "" {
			sessionKey := q.Get("state")
			if err := srv.KillSession(sessionKey); err != nil {
				log.Errorf("Failed killing sessionKey %q: %v", sessionKey, err)
			}
			renderLoginPage(w, r, srv, idpcs, register, tpl)
			return
		}

		connectorID := q.Get("connector_id")
		idpc, ok := idx[connectorID]
		if !ok {
			renderLoginPage(w, r, srv, idpcs, register, tpl)
			return
		}

		acr, err := oauth2.ParseAuthCodeRequest(q)
		if err != nil {
			log.Errorf("Invalid auth request: %v", err)
			writeAuthError(w, err, acr.State)
			return
		}

		cli, err := srv.Client(acr.ClientID)
		if err != nil {
			log.Errorf("Failed fetching client %q from repo: %v", acr.ClientID, err)
			writeAuthError(w, oauth2.NewError(oauth2.ErrorServerError), acr.State)
			return
		}
		if err == client.ErrorNotFound {
			log.Errorf("Client %q not found", acr.ClientID)
			writeAuthError(w, oauth2.NewError(oauth2.ErrorInvalidRequest), acr.State)
			return
		}

		redirectURL, err := cli.ValidRedirectURL(acr.RedirectURL)
		if err != nil {
			switch err {
			case (client.ErrorCantChooseRedirectURL):
				log.Errorf("Request must provide redirect URL as client %q has registered many", acr.ClientID)
				writeAuthError(w, oauth2.NewError(oauth2.ErrorInvalidRequest), acr.State)
				return
			case (client.ErrorInvalidRedirectURL):
				log.Errorf("Request provided unregistered redirect URL: %s", acr.RedirectURL)
				writeAuthError(w, oauth2.NewError(oauth2.ErrorInvalidRequest), acr.State)
				return
			case (client.ErrorNoValidRedirectURLs):
				log.Errorf("There are no registered URLs for the requested client: %s", acr.RedirectURL)
				writeAuthError(w, oauth2.NewError(oauth2.ErrorInvalidRequest), acr.State)
				return
			}
		}

		if acr.ResponseType != oauth2.ResponseTypeCode {
			log.Errorf("unexpected ResponseType: %v: ", acr.ResponseType)
			redirectAuthError(w, oauth2.NewError(oauth2.ErrorUnsupportedResponseType), acr.State, redirectURL)
			return
		}

		// Check scopes.
		if scopeErr := validateScopes(srv, acr.ClientID, acr.Scope); scopeErr != nil {
			log.Error(scopeErr)
			writeAuthError(w, scopeErr, acr.State)
			return
		}

		nonce := q.Get("nonce")

		key, err := srv.NewSession(connectorID, acr.ClientID, acr.State, redirectURL, nonce, register, acr.Scope)
		if err != nil {
			log.Errorf("Error creating new session: %v: ", err)
			redirectAuthError(w, err, acr.State, redirectURL)
			return
		}

		if register {
			_, ok := idpc.(*connector.LocalConnector)
			if ok {
				q := url.Values{}
				q.Set("code", key)
				ru := path.Join(baseURL.Path, httpPathRegister) + "?" + q.Encode()
				w.Header().Set("Location", ru)
				w.WriteHeader(http.StatusFound)
				return
			}
		}

		var p string
		if register {
			p = "select_account consent"
		}
		if shouldReprompt(r) || register {
			p = "select_account"
		}
		lu, err := idpc.LoginURL(key, p)
		if err != nil {
			log.Errorf("Connector.LoginURL failed: %v", err)
			redirectAuthError(w, err, acr.State, redirectURL)
			return
		}

		http.SetCookie(w, createLastSeenCookie())
		w.Header().Set("Location", lu)
		w.WriteHeader(http.StatusFound)
		return
	}
}