oauth2_proxy/providers/oidc.go
2019-07-19 08:59:29 -05:00

181 lines
4.9 KiB
Go

package providers
import (
"context"
"fmt"
"net/http"
"time"
oidc "github.com/coreos/go-oidc"
"github.com/pusher/oauth2_proxy/pkg/apis/sessions"
"github.com/pusher/oauth2_proxy/pkg/requests"
"golang.org/x/oauth2"
)
// OIDCProvider represents an OIDC based Identity Provider
type OIDCProvider struct {
*ProviderData
Verifier *oidc.IDTokenVerifier
AllowUnverifiedEmail bool
}
// NewOIDCProvider initiates a new OIDCProvider
func NewOIDCProvider(p *ProviderData) *OIDCProvider {
p.ProviderName = "OpenID Connect"
return &OIDCProvider{ProviderData: p}
}
// Redeem exchanges the OAuth2 authentication token for an ID token
func (p *OIDCProvider) Redeem(redirectURL, code string) (s *sessions.SessionState, err error) {
ctx := context.Background()
c := oauth2.Config{
ClientID: p.ClientID,
ClientSecret: p.ClientSecret,
Endpoint: oauth2.Endpoint{
TokenURL: p.RedeemURL.String(),
},
RedirectURL: redirectURL,
}
token, err := c.Exchange(ctx, code)
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 *sessions.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 *sessions.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.CreatedAt = newSession.CreatedAt
s.ExpiresOn = newSession.ExpiresOn
s.Email = newSession.Email
return
}
func (p *OIDCProvider) createSessionState(ctx context.Context, token *oauth2.Token) (*sessions.SessionState, error) {
rawIDToken, ok := token.Extra("id_token").(string)
if !ok {
return nil, fmt.Errorf("token response did not contain an id_token")
}
// Parse and verify ID Token payload.
idToken, err := p.Verifier.Verify(ctx, rawIDToken)
if err != nil {
return nil, fmt.Errorf("could not verify id_token: %v", err)
}
// Extract custom claims.
var claims struct {
Subject string `json:"sub"`
Email string `json:"email"`
Verified *bool `json:"email_verified"`
}
if err := idToken.Claims(&claims); err != nil {
return nil, fmt.Errorf("failed to parse id_token claims: %v", err)
}
if claims.Email == "" {
if p.ProfileURL.String() == "" {
return nil, fmt.Errorf("id_token did not contain an email")
}
// If the userinfo endpoint profileURL is defined, then there is a chance the userinfo
// contents at the profileURL contains the email.
// Make a query to the userinfo endpoint, and attempt to locate the email from there.
req, err := http.NewRequest("GET", p.ProfileURL.String(), nil)
if err != nil {
return nil, err
}
req.Header = getOIDCHeader(token.AccessToken)
respJSON, err := requests.Request(req)
if err != nil {
return nil, err
}
email, err := respJSON.Get("email").String()
if err != nil {
return nil, fmt.Errorf("Neither id_token nor userinfo endpoint contained an email")
}
claims.Email = email
}
if !p.AllowUnverifiedEmail && claims.Verified != nil && !*claims.Verified {
return nil, fmt.Errorf("email in id_token (%s) isn't verified", claims.Email)
}
return &sessions.SessionState{
AccessToken: token.AccessToken,
IDToken: rawIDToken,
RefreshToken: token.RefreshToken,
CreatedAt: time.Now(),
ExpiresOn: idToken.Expiry,
Email: claims.Email,
User: claims.Subject,
}, nil
}
// ValidateSessionState checks that the session's IDToken is still valid
func (p *OIDCProvider) ValidateSessionState(s *sessions.SessionState) bool {
ctx := context.Background()
_, err := p.Verifier.Verify(ctx, s.IDToken)
if err != nil {
return false
}
return true
}
func getOIDCHeader(accessToken string) http.Header {
header := make(http.Header)
header.Set("Accept", "application/json")
header.Set("Authorization", fmt.Sprintf("Bearer %s", accessToken))
return header
}