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dex/server/oauth2.go
Eric Chiang f926d74157 server: fixes for the implicit and hybrid flow
Accept the following response_type for the implicit flow:

    id_token
    token id_token

And the following for hybrid flow

    code id_token
    code token
    code token id_token

This corrects the previous behavior of the implicit flow, which
only accepted "token" (now correctly rejected).
2017-01-10 16:20:17 -08:00

390 lines
10 KiB
Go

package server
import (
"encoding/json"
"fmt"
"net/http"
"net/url"
"strconv"
"strings"
"time"
"github.com/coreos/dex/connector"
"github.com/coreos/dex/storage"
)
// TODO(ericchiang): clean this file up and figure out more idiomatic error handling.
// authErr is an error response to an authorization request.
// See: https://tools.ietf.org/html/rfc6749#section-4.1.2.1
type authErr struct {
State string
RedirectURI string
Type string
Description string
}
func (err *authErr) Status() int {
if err.State == errServerError {
return http.StatusInternalServerError
}
return http.StatusBadRequest
}
func (err *authErr) Error() string {
return err.Description
}
func (err *authErr) Handle() (http.Handler, bool) {
// Didn't get a valid redirect URI.
if err.RedirectURI == "" {
return nil, false
}
hf := func(w http.ResponseWriter, r *http.Request) {
v := url.Values{}
v.Add("state", err.State)
v.Add("error", err.Type)
if err.Description != "" {
v.Add("error_description", err.Description)
}
var redirectURI string
if strings.Contains(err.RedirectURI, "?") {
redirectURI = err.RedirectURI + "&" + v.Encode()
} else {
redirectURI = err.RedirectURI + "?" + v.Encode()
}
http.Redirect(w, r, redirectURI, http.StatusSeeOther)
}
return http.HandlerFunc(hf), true
}
func tokenErr(w http.ResponseWriter, typ, description string, statusCode int) error {
data := struct {
Error string `json:"error"`
Description string `json:"error_description,omitempty"`
}{typ, description}
body, err := json.Marshal(data)
if err != nil {
return fmt.Errorf("failed to marshal token error response: %v", err)
}
w.Header().Set("Content-Type", "application/json")
w.Header().Set("Content-Length", strconv.Itoa(len(body)))
w.WriteHeader(statusCode)
w.Write(body)
return nil
}
const (
errInvalidRequest = "invalid_request"
errUnauthorizedClient = "unauthorized_client"
errAccessDenied = "access_denied"
errUnsupportedResponseType = "unsupported_response_type"
errInvalidScope = "invalid_scope"
errServerError = "server_error"
errTemporarilyUnavailable = "temporarily_unavailable"
errUnsupportedGrantType = "unsupported_grant_type"
errInvalidGrant = "invalid_grant"
errInvalidClient = "invalid_client"
)
const (
scopeOfflineAccess = "offline_access" // Request a refresh token.
scopeOpenID = "openid"
scopeGroups = "groups"
scopeEmail = "email"
scopeProfile = "profile"
scopeCrossClientPrefix = "audience:server:client_id:"
)
const (
redirectURIOOB = "urn:ietf:wg:oauth:2.0:oob"
)
const (
grantTypeAuthorizationCode = "authorization_code"
grantTypeRefreshToken = "refresh_token"
)
const (
responseTypeCode = "code" // "Regular" flow
responseTypeToken = "token" // Implicit flow for frontend apps.
responseTypeIDToken = "id_token" // ID Token in url fragment
)
func parseScopes(scopes []string) connector.Scopes {
var s connector.Scopes
for _, scope := range scopes {
switch scope {
case scopeOfflineAccess:
s.OfflineAccess = true
case scopeGroups:
s.Groups = true
}
}
return s
}
type audience []string
func (a audience) MarshalJSON() ([]byte, error) {
if len(a) == 1 {
return json.Marshal(a[0])
}
return json.Marshal([]string(a))
}
type idTokenClaims struct {
Issuer string `json:"iss"`
Subject string `json:"sub"`
Audience audience `json:"aud"`
Expiry int64 `json:"exp"`
IssuedAt int64 `json:"iat"`
AuthorizingParty string `json:"azp,omitempty"`
Nonce string `json:"nonce,omitempty"`
Email string `json:"email,omitempty"`
EmailVerified *bool `json:"email_verified,omitempty"`
Groups []string `json:"groups,omitempty"`
Name string `json:"name,omitempty"`
}
func (s *Server) newIDToken(clientID string, claims storage.Claims, scopes []string, nonce string) (idToken string, expiry time.Time, err error) {
issuedAt := s.now()
expiry = issuedAt.Add(s.idTokensValidFor)
tok := idTokenClaims{
Issuer: s.issuerURL.String(),
Subject: claims.UserID,
Nonce: nonce,
Expiry: expiry.Unix(),
IssuedAt: issuedAt.Unix(),
}
for _, scope := range scopes {
switch {
case scope == scopeEmail:
tok.Email = claims.Email
tok.EmailVerified = &claims.EmailVerified
case scope == scopeGroups:
tok.Groups = claims.Groups
case scope == scopeProfile:
tok.Name = claims.Username
default:
peerID, ok := parseCrossClientScope(scope)
if !ok {
continue
}
isTrusted, err := s.validateCrossClientTrust(clientID, peerID)
if err != nil {
return "", expiry, err
}
if !isTrusted {
// TODO(ericchiang): propagate this error to the client.
return "", expiry, fmt.Errorf("peer (%s) does not trust client", peerID)
}
tok.Audience = append(tok.Audience, peerID)
}
}
if len(tok.Audience) == 0 {
tok.Audience = audience{clientID}
} else {
tok.AuthorizingParty = clientID
}
payload, err := json.Marshal(tok)
if err != nil {
return "", expiry, fmt.Errorf("could not serialize claims: %v", err)
}
keys, err := s.storage.GetKeys()
if err != nil {
s.logger.Errorf("Failed to get keys: %v", err)
return "", expiry, err
}
if idToken, err = keys.Sign(payload); err != nil {
return "", expiry, fmt.Errorf("failed to sign payload: %v", err)
}
return idToken, expiry, nil
}
// parse the initial request from the OAuth2 client.
func (s *Server) parseAuthorizationRequest(r *http.Request) (req storage.AuthRequest, oauth2Err *authErr) {
q := r.URL.Query()
redirectURI, err := url.QueryUnescape(q.Get("redirect_uri"))
if err != nil {
return req, &authErr{"", "", errInvalidRequest, "No redirect_uri provided."}
}
clientID := q.Get("client_id")
state := q.Get("state")
nonce := q.Get("nonce")
// Some clients, like the old go-oidc, provide extra whitespace. Tolerate this.
scopes := strings.Fields(q.Get("scope"))
responseTypes := strings.Fields(q.Get("response_type"))
client, err := s.storage.GetClient(clientID)
if err != nil {
if err == storage.ErrNotFound {
description := fmt.Sprintf("Invalid client_id (%q).", clientID)
return req, &authErr{"", "", errUnauthorizedClient, description}
}
s.logger.Errorf("Failed to get client: %v", err)
return req, &authErr{"", "", errServerError, ""}
}
if !validateRedirectURI(client, redirectURI) {
description := fmt.Sprintf("Unregistered redirect_uri (%q).", redirectURI)
return req, &authErr{"", "", errInvalidRequest, description}
}
// From here on out, we want to redirect back to the client with an error.
newErr := func(typ, format string, a ...interface{}) *authErr {
return &authErr{state, redirectURI, typ, fmt.Sprintf(format, a...)}
}
var (
unrecognized []string
invalidScopes []string
)
hasOpenIDScope := false
for _, scope := range scopes {
switch scope {
case scopeOpenID:
hasOpenIDScope = true
case scopeOfflineAccess, scopeEmail, scopeProfile, scopeGroups:
default:
peerID, ok := parseCrossClientScope(scope)
if !ok {
unrecognized = append(unrecognized, scope)
continue
}
isTrusted, err := s.validateCrossClientTrust(clientID, peerID)
if err != nil {
return req, newErr(errServerError, "Internal server error.")
}
if !isTrusted {
invalidScopes = append(invalidScopes, scope)
}
}
}
if !hasOpenIDScope {
return req, newErr("invalid_scope", `Missing required scope(s) ["openid"].`)
}
if len(unrecognized) > 0 {
return req, newErr("invalid_scope", "Unrecognized scope(s) %q", unrecognized)
}
if len(invalidScopes) > 0 {
return req, newErr("invalid_scope", "Client can't request scope(s) %q", invalidScopes)
}
var rt struct {
code bool
idToken bool
token bool
}
for _, responseType := range responseTypes {
switch responseType {
case responseTypeCode:
rt.code = true
case responseTypeIDToken:
rt.idToken = true
case responseTypeToken:
rt.token = true
default:
return req, newErr("invalid_request", "Invalid response type %q", responseType)
}
if !s.supportedResponseTypes[responseType] {
return req, newErr(errUnsupportedResponseType, "Unsupported response type %q", responseType)
}
}
if len(responseTypes) == 0 {
return req, newErr("invalid_requests", "No response_type provided")
}
if rt.token && !rt.code && !rt.idToken {
// "token" can't be provided by its own.
//
// https://openid.net/specs/openid-connect-core-1_0.html#Authentication
return req, newErr("invalid_request", "Response type 'token' must be provided with type 'id_token' and/or 'code'")
}
if !rt.code {
// Either "id_token code" or "id_token" has been provided which implies the
// implicit flow. Implicit flow requires a nonce value.
//
// https://openid.net/specs/openid-connect-core-1_0.html#ImplicitAuthRequest
if nonce == "" {
return req, newErr("invalid_request", "Response type 'token' requires a 'nonce' value.")
}
}
if rt.token {
if redirectURI == redirectURIOOB {
err := fmt.Sprintf("Cannot use response type 'token' with redirect_uri '%s'.", redirectURIOOB)
return req, newErr("invalid_request", err)
}
}
return storage.AuthRequest{
ID: storage.NewID(),
ClientID: client.ID,
State: state,
Nonce: nonce,
ForceApprovalPrompt: q.Get("approval_prompt") == "force",
Scopes: scopes,
RedirectURI: redirectURI,
ResponseTypes: responseTypes,
}, nil
}
func parseCrossClientScope(scope string) (peerID string, ok bool) {
if ok = strings.HasPrefix(scope, scopeCrossClientPrefix); ok {
peerID = scope[len(scopeCrossClientPrefix):]
}
return
}
func (s *Server) validateCrossClientTrust(clientID, peerID string) (trusted bool, err error) {
if peerID == clientID {
return true, nil
}
peer, err := s.storage.GetClient(peerID)
if err != nil {
if err != storage.ErrNotFound {
s.logger.Errorf("Failed to get client: %v", err)
return false, err
}
return false, nil
}
for _, id := range peer.TrustedPeers {
if id == clientID {
return true, nil
}
}
return false, nil
}
func validateRedirectURI(client storage.Client, redirectURI string) bool {
if !client.Public {
for _, uri := range client.RedirectURIs {
if redirectURI == uri {
return true
}
}
return false
}
if redirectURI == redirectURIOOB {
return true
}
if !strings.HasPrefix(redirectURI, "http://localhost:") {
return false
}
n, err := strconv.Atoi(strings.TrimPrefix(redirectURI, "https://localhost:"))
return err == nil && n <= 0
}