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dex/vendor/github.com/ericchiang/oidc/oidc.go

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2016-07-25 20:00:28 +00:00
package oidc
import (
"encoding/json"
"errors"
"fmt"
"io/ioutil"
"net/http"
"strings"
"time"
"golang.org/x/net/context"
"golang.org/x/oauth2"
)
var (
// ErrTokenExpired indicates that a token parsed by a verifier has expired.
ErrTokenExpired = errors.New("ID Token expired")
// ErrNotSupported indicates that the requested optional OpenID Connect endpoint is not supported by the provider.
ErrNotSupported = errors.New("endpoint not supported")
)
const (
// ScopeOpenID is the mandatory scope for all OpenID Connect OAuth2 requests.
ScopeOpenID = "openid"
// ScopeOfflineAccess is an optional scope defined by OpenID Connect for requesting
// OAuth2 refresh tokens.
//
// Support for this scope differs between OpenID Connect providers. For instance
// Google rejects it, favoring appending "access_type=offline" as part of the
// authorization request instead.
//
// See: https://openid.net/specs/openid-connect-core-1_0.html#OfflineAccess
ScopeOfflineAccess = "offline_access"
)
// Provider contains the subset of the OpenID Connect provider metadata needed to request
// and verify ID Tokens.
type Provider struct {
Issuer string `json:"issuer"`
AuthURL string `json:"authorization_endpoint"`
TokenURL string `json:"token_endpoint"`
JWKSURL string `json:"jwks_uri"`
UserInfoURL string `json:"userinfo_endpoint"`
// Optionally contains extra claims.
raw map[string]interface{}
}
// NewProvider uses the OpenID Connect disovery mechanism to construct a Provider.
func NewProvider(ctx context.Context, issuer string) (*Provider, error) {
wellKnown := strings.TrimSuffix(issuer, "/") + "/.well-known/openid-configuration"
resp, err := contextClient(ctx).Get(wellKnown)
if err != nil {
return nil, err
}
body, err := ioutil.ReadAll(resp.Body)
if err != nil {
return nil, err
}
if resp.StatusCode != http.StatusOK {
return nil, fmt.Errorf("%s: %s", resp.Status, body)
}
defer resp.Body.Close()
var p Provider
if err := json.Unmarshal(body, &p); err != nil {
return nil, fmt.Errorf("oidc: failed to decode provider discovery object: %v", err)
}
// raw claims do not get error checks
json.Unmarshal(body, &p.raw)
if p.Issuer != issuer {
return nil, fmt.Errorf("oidc: issuer did not match the issuer returned by provider, expected %q got %q", issuer, p.Issuer)
}
return &p, nil
}
// Extra returns additional fields returned by the server during discovery.
func (p *Provider) Extra(key string) interface{} {
if p.raw != nil {
return p.raw[key]
}
return nil
}
// Endpoint returns the OAuth2 auth and token endpoints for the given provider.
func (p *Provider) Endpoint() oauth2.Endpoint {
return oauth2.Endpoint{AuthURL: p.AuthURL, TokenURL: p.TokenURL}
}
// UserInfo represents the OpenID Connect userinfo claims.
type UserInfo struct {
Subject string `json:"sub"`
Profile string `json:"profile"`
Email string `json:"email"`
EmailVerified bool `json:"email_verified"`
// Optionally contains extra claims.
raw map[string]interface{}
}
// Extra returns additional claims returned by the server.
func (u *UserInfo) Extra(key string) interface{} {
if u.raw != nil {
return u.raw[key]
}
return nil
}
// UserInfo uses the token source to query the provider's user info endpoint.
func (p *Provider) UserInfo(ctx context.Context, tokenSource oauth2.TokenSource) (*UserInfo, error) {
if p.UserInfoURL == "" {
return nil, ErrNotSupported
}
cli := oauth2.NewClient(ctx, tokenSource)
resp, err := cli.Get(p.UserInfoURL)
if err != nil {
return nil, err
}
defer resp.Body.Close()
body, err := ioutil.ReadAll(resp.Body)
if err != nil {
return nil, err
}
if resp.StatusCode != http.StatusOK {
return nil, fmt.Errorf("%s: %s", resp.Status, body)
}
var userInfo UserInfo
if err := json.Unmarshal(body, &userInfo); err != nil {
return nil, fmt.Errorf("oidc: failed to decode userinfo: %v", err)
}
// raw claims do not get error checks
json.Unmarshal(body, &userInfo.raw)
return &userInfo, nil
}
// IDTokenVerifier provides verification for ID Tokens.
type IDTokenVerifier struct {
issuer string
keySet *remoteKeySet
options []VerificationOption
}
// Verify parse the raw ID Token, verifies it's been signed by the provider, preforms
// additional verification, such as checking the expiration, and returns the claims.
func (v *IDTokenVerifier) Verify(rawIDToken string) (payload []byte, err error) {
payload, err = v.keySet.verifyJWT(rawIDToken)
if err != nil {
return nil, err
}
var token struct {
Exp float64 `json:"exp"` // JSON numbers are always float64s.
Issuer string `json:"iss"`
}
if err := json.Unmarshal(payload, &token); err != nil {
return nil, fmt.Errorf("oidc: failed to unmarshal claims: %v", err)
}
if v.issuer != token.Issuer {
return nil, fmt.Errorf("oidc: iss field did not match provider issuer")
}
if time.Unix(int64(token.Exp), 0).Before(time.Now().Round(time.Second)) {
return nil, ErrTokenExpired
}
for _, option := range v.options {
if err := option.verifyIDTokenPayload(payload); err != nil {
return nil, err
}
}
return payload, nil
}
// NewVerifier returns an IDTokenVerifier that uses the provider's key set to verify JWTs.
//
// The verifier queries the provider to update keys when a signature cannot be verified by the
// set of keys cached from the previous request.
func (p *Provider) NewVerifier(ctx context.Context, options ...VerificationOption) *IDTokenVerifier {
return &IDTokenVerifier{
issuer: p.Issuer,
keySet: newRemoteKeySet(ctx, p.JWKSURL),
options: options,
}
}
// VerificationOption is an option provided to Provider.NewVerifier.
type VerificationOption interface {
verifyIDTokenPayload(raw []byte) error
}
// VerifyAudience ensures that an ID Token was issued for the specific client.
//
// Note that a verified token may be valid for other clients, as OpenID Connect allows a token to have
// multiple audiences.
func VerifyAudience(clientID string) VerificationOption {
return clientVerifier{clientID}
}
type clientVerifier struct {
clientID string
}
func (c clientVerifier) verifyIDTokenPayload(payload []byte) error {
var token struct {
Aud string `json:"aud"`
}
if err := json.Unmarshal(payload, &token); err == nil {
if token.Aud != c.clientID {
return errors.New("oidc: id token aud field did not match client_id")
}
return nil
}
// Aud can optionally be an array of strings
var token2 struct {
Aud []string `json:"aud"`
}
if err := json.Unmarshal(payload, &token2); err != nil {
return fmt.Errorf("oidc: failed to unmarshal aud claim: %v", err)
}
for _, aud := range token2.Aud {
if aud == c.clientID {
return nil
}
}
return errors.New("oidc: id token aud field did not match client_id")
}
// This method is internal to golang.org/x/oauth2. Just copy it.
func contextClient(ctx context.Context) *http.Client {
if ctx != nil {
if hc, ok := ctx.Value(oauth2.HTTPClient).(*http.Client); ok {
return hc
}
}
return http.DefaultClient
}