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dex/connector/oidc/oidc.go
2019-06-03 14:09:07 +02:00

284 lines
8.2 KiB
Go

// Package oidc implements logging in through OpenID Connect providers.
package oidc
import (
"context"
"errors"
"fmt"
"net/http"
"net/url"
"strings"
"sync"
"github.com/coreos/go-oidc"
"golang.org/x/oauth2"
"github.com/dexidp/dex/connector"
"github.com/dexidp/dex/pkg/log"
)
// Config holds configuration options for OpenID Connect logins.
type Config struct {
Issuer string `json:"issuer"`
ClientID string `json:"clientID"`
ClientSecret string `json:"clientSecret"`
RedirectURI string `json:"redirectURI"`
// Causes client_secret to be passed as POST parameters instead of basic
// auth. This is specifically "NOT RECOMMENDED" by the OAuth2 RFC, but some
// providers require it.
//
// https://tools.ietf.org/html/rfc6749#section-2.3.1
BasicAuthUnsupported *bool `json:"basicAuthUnsupported"`
Scopes []string `json:"scopes"` // defaults to "profile" and "email"
// Optional list of whitelisted domains when using Google
// If this field is nonempty, only users from a listed domain will be allowed to log in
HostedDomains []string `json:"hostedDomains"`
// Override the value of email_verifed to true in the returned claims
InsecureSkipEmailVerified bool `json:"insecureSkipEmailVerified"`
// GetUserInfo uses the userinfo endpoint to get additional claims for
// the token. This is especially useful where upstreams return "thin"
// id tokens
GetUserInfo bool `json:"getUserInfo"`
// Configurable key which contains the user id claim
UserIDKey string `json:"userIDKey"`
// Configurable key which contains the user name claim
UserNameKey string `json:"userNameKey"`
}
// Domains that don't support basic auth. golang.org/x/oauth2 has an internal
// list, but it only matches specific URLs, not top level domains.
var brokenAuthHeaderDomains = []string{
// See: https://github.com/dexidp/dex/issues/859
"okta.com",
"oktapreview.com",
}
// Detect auth header provider issues for known providers. This lets users
// avoid having to explicitly set "basicAuthUnsupported" in their config.
//
// Setting the config field always overrides values returned by this function.
func knownBrokenAuthHeaderProvider(issuerURL string) bool {
if u, err := url.Parse(issuerURL); err == nil {
for _, host := range brokenAuthHeaderDomains {
if u.Host == host || strings.HasSuffix(u.Host, "."+host) {
return true
}
}
}
return false
}
// golang.org/x/oauth2 doesn't do internal locking. Need to do it in this
// package ourselves and hope that other packages aren't calling it at the
// same time.
var registerMu = new(sync.Mutex)
func registerBrokenAuthHeaderProvider(url string) {
registerMu.Lock()
defer registerMu.Unlock()
oauth2.RegisterBrokenAuthHeaderProvider(url)
}
// Open returns a connector which can be used to login users through an upstream
// OpenID Connect provider.
func (c *Config) Open(id string, logger log.Logger) (conn connector.Connector, err error) {
ctx, cancel := context.WithCancel(context.Background())
provider, err := oidc.NewProvider(ctx, c.Issuer)
if err != nil {
cancel()
return nil, fmt.Errorf("failed to get provider: %v", err)
}
if c.BasicAuthUnsupported != nil {
// Setting "basicAuthUnsupported" always overrides our detection.
if *c.BasicAuthUnsupported {
registerBrokenAuthHeaderProvider(provider.Endpoint().TokenURL)
}
} else if knownBrokenAuthHeaderProvider(c.Issuer) {
registerBrokenAuthHeaderProvider(provider.Endpoint().TokenURL)
}
scopes := []string{oidc.ScopeOpenID}
if len(c.Scopes) > 0 {
scopes = append(scopes, c.Scopes...)
} else {
scopes = append(scopes, "profile", "email")
}
clientID := c.ClientID
return &oidcConnector{
provider: provider,
redirectURI: c.RedirectURI,
oauth2Config: &oauth2.Config{
ClientID: clientID,
ClientSecret: c.ClientSecret,
Endpoint: provider.Endpoint(),
Scopes: scopes,
RedirectURL: c.RedirectURI,
},
verifier: provider.Verifier(
&oidc.Config{ClientID: clientID},
),
logger: logger,
cancel: cancel,
hostedDomains: c.HostedDomains,
insecureSkipEmailVerified: c.InsecureSkipEmailVerified,
getUserInfo: c.GetUserInfo,
userIDKey: c.UserIDKey,
userNameKey: c.UserNameKey,
}, nil
}
var (
_ connector.CallbackConnector = (*oidcConnector)(nil)
_ connector.RefreshConnector = (*oidcConnector)(nil)
)
type oidcConnector struct {
provider *oidc.Provider
redirectURI string
oauth2Config *oauth2.Config
verifier *oidc.IDTokenVerifier
ctx context.Context
cancel context.CancelFunc
logger log.Logger
hostedDomains []string
insecureSkipEmailVerified bool
getUserInfo bool
userIDKey string
userNameKey string
}
func (c *oidcConnector) Close() error {
c.cancel()
return nil
}
func (c *oidcConnector) LoginURL(s connector.Scopes, callbackURL, state string) (string, error) {
if c.redirectURI != callbackURL {
return "", fmt.Errorf("expected callback URL %q did not match the URL in the config %q", callbackURL, c.redirectURI)
}
if len(c.hostedDomains) > 0 {
preferredDomain := c.hostedDomains[0]
if len(c.hostedDomains) > 1 {
preferredDomain = "*"
}
return c.oauth2Config.AuthCodeURL(state, oauth2.SetAuthURLParam("hd", preferredDomain)), nil
}
return c.oauth2Config.AuthCodeURL(state), nil
}
type oauth2Error struct {
error string
errorDescription string
}
func (e *oauth2Error) Error() string {
if e.errorDescription == "" {
return e.error
}
return e.error + ": " + e.errorDescription
}
func (c *oidcConnector) HandleCallback(s connector.Scopes, r *http.Request) (identity connector.Identity, err error) {
q := r.URL.Query()
if errType := q.Get("error"); errType != "" {
return identity, &oauth2Error{errType, q.Get("error_description")}
}
token, err := c.oauth2Config.Exchange(r.Context(), q.Get("code"))
if err != nil {
return identity, fmt.Errorf("oidc: failed to get token: %v", err)
}
rawIDToken, ok := token.Extra("id_token").(string)
if !ok {
return identity, errors.New("oidc: no id_token in token response")
}
idToken, err := c.verifier.Verify(r.Context(), rawIDToken)
if err != nil {
return identity, fmt.Errorf("oidc: failed to verify ID Token: %v", err)
}
var claims map[string]interface{}
if err := idToken.Claims(&claims); err != nil {
return identity, fmt.Errorf("oidc: failed to decode claims: %v", err)
}
userNameKey := "name"
if c.userNameKey != "" {
userNameKey = c.userNameKey
}
name, found := claims[userNameKey].(string)
if !found {
return identity, fmt.Errorf("missing \"%s\" claim", userNameKey)
}
email, found := claims["email"].(string)
if !found {
return identity, errors.New("missing \"email\" claim")
}
emailVerified, found := claims["email_verified"].(bool)
if !found {
if c.insecureSkipEmailVerified {
emailVerified = true
} else {
return identity, errors.New("missing \"email_verified\" claim")
}
}
hostedDomain, _ := claims["hd"].(string)
if len(c.hostedDomains) > 0 {
found := false
for _, domain := range c.hostedDomains {
if hostedDomain == domain {
found = true
break
}
}
if !found {
return identity, fmt.Errorf("oidc: unexpected hd claim %v", hostedDomain)
}
}
if c.getUserInfo {
userInfo, err := c.provider.UserInfo(r.Context(), oauth2.StaticTokenSource(token))
if err != nil {
return identity, fmt.Errorf("oidc: error loading userinfo: %v", err)
}
if err := userInfo.Claims(&claims); err != nil {
return identity, fmt.Errorf("oidc: failed to decode userinfo claims: %v", err)
}
}
identity = connector.Identity{
UserID: idToken.Subject,
Username: name,
Email: email,
EmailVerified: emailVerified,
}
if c.userIDKey != "" {
userID, found := claims[c.userIDKey].(string)
if !found {
return identity, fmt.Errorf("oidc: not found %v claim", c.userIDKey)
}
identity.UserID = userID
}
return identity, nil
}
// Refresh is implemented for backwards compatibility, even though it's a no-op.
func (c *oidcConnector) Refresh(ctx context.Context, s connector.Scopes, identity connector.Identity) (connector.Identity, error) {
return identity, nil
}