bouncer/internal/proxy/director/layer/authn/oidc/authenticator.go
William Petit 132bf1e642
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feat(authn-oidc): allow for dynamic post-logout redirection
2024-05-24 17:01:06 +02:00

412 lines
10 KiB
Go

package oidc
import (
"bytes"
"context"
"crypto/tls"
"fmt"
"net/http"
"net/url"
"slices"
"strings"
"text/template"
"time"
"forge.cadoles.com/Cadoles/go-proxy/wildcard"
"forge.cadoles.com/cadoles/bouncer/internal/proxy/director"
"forge.cadoles.com/cadoles/bouncer/internal/proxy/director/layer/authn"
"forge.cadoles.com/cadoles/bouncer/internal/store"
"github.com/coreos/go-oidc/v3/oidc"
"github.com/gorilla/sessions"
"github.com/pkg/errors"
"github.com/prometheus/client_golang/prometheus"
"gitlab.com/wpetit/goweb/logger"
)
type Authenticator struct {
store sessions.Store
httpTransport *http.Transport
httpClientTimeout time.Duration
}
func (a *Authenticator) PreAuthentication(w http.ResponseWriter, r *http.Request, layer *store.Layer) error {
ctx := r.Context()
originalURL, err := director.OriginalURL(ctx)
if err != nil {
return errors.WithStack(err)
}
options, err := fromStoreOptions(layer.Options)
if err != nil {
return errors.WithStack(err)
}
sess, err := a.store.Get(r, a.getCookieName(options.Cookie.Name, layer.Name))
if err != nil {
logger.Error(ctx, "could not retrieve session", logger.E(errors.WithStack(err)))
}
loginCallbackURL, err := a.getLoginCallbackURL(originalURL, layer.Proxy, layer.Name, options)
if err != nil {
return errors.WithStack(err)
}
client, err := a.getClient(options, loginCallbackURL.String())
if err != nil {
return errors.WithStack(err)
}
loginCallbackPathPattern, err := a.templatize(options.OIDC.MatchLoginCallbackPath, layer.Proxy, layer.Name)
if err != nil {
return errors.WithStack(err)
}
logoutPathPattern, err := a.templatize(options.OIDC.MatchLogoutPath, layer.Proxy, layer.Name)
if err != nil {
return errors.WithStack(err)
}
logger.Debug(ctx, "checking url", logger.F("loginCallbackPathPattern", loginCallbackPathPattern), logger.F("logoutPathPattern", logoutPathPattern))
switch {
case wildcard.Match(originalURL.Path, loginCallbackPathPattern):
if err := client.HandleCallback(w, r, sess); err != nil {
return errors.WithStack(err)
}
metricLoginSuccessesTotal.With(prometheus.Labels{
metricLabelLayer: string(layer.Name),
metricLabelProxy: string(layer.Proxy),
}).Add(1)
case wildcard.Match(originalURL.Path, logoutPathPattern):
postLogoutRedirectURL := r.URL.Query().Get("redirect")
if postLogoutRedirectURL != "" {
isAuthorized := slices.Contains(options.OIDC.PostLogoutRedirectURLs, postLogoutRedirectURL)
if !isAuthorized {
http.Error(w, "unauthorized post-logout redirect", http.StatusBadRequest)
return errors.WithStack(authn.ErrSkipRequest)
}
}
if postLogoutRedirectURL == "" {
if options.OIDC.PublicBaseURL != "" {
postLogoutRedirectURL = options.OIDC.PublicBaseURL
} else {
postLogoutRedirectURL = originalURL.Scheme + "://" + originalURL.Host
}
}
if err := client.HandleLogout(w, r, sess, postLogoutRedirectURL); err != nil {
return errors.WithStack(err)
}
metricLogoutsTotal.With(prometheus.Labels{
metricLabelLayer: string(layer.Name),
metricLabelProxy: string(layer.Proxy),
}).Add(1)
}
return nil
}
// Authenticate implements authn.Authenticator.
func (a *Authenticator) Authenticate(w http.ResponseWriter, r *http.Request, layer *store.Layer) (*authn.User, error) {
ctx := r.Context()
options, err := fromStoreOptions(layer.Options)
if err != nil {
return nil, errors.WithStack(err)
}
sess, err := a.store.Get(r, a.getCookieName(options.Cookie.Name, layer.Name))
if err != nil {
return nil, errors.WithStack(err)
}
defer func() {
if err := sess.Save(r, w); err != nil {
logger.Error(ctx, "could not save session", logger.E(errors.WithStack(err)))
}
}()
sess.Options.Domain = options.Cookie.Domain
sess.Options.HttpOnly = options.Cookie.HTTPOnly
sess.Options.MaxAge = int(options.Cookie.MaxAge.Seconds())
sess.Options.Path = options.Cookie.Path
switch options.Cookie.SameSite {
case "lax":
sess.Options.SameSite = http.SameSiteLaxMode
case "strict":
sess.Options.SameSite = http.SameSiteStrictMode
case "none":
sess.Options.SameSite = http.SameSiteNoneMode
default:
sess.Options.SameSite = http.SameSiteDefaultMode
}
originalURL, err := director.OriginalURL(ctx)
if err != nil {
return nil, errors.WithStack(err)
}
loginCallbackURL, err := a.getLoginCallbackURL(originalURL, layer.Proxy, layer.Name, options)
if err != nil {
return nil, errors.WithStack(err)
}
client, err := a.getClient(options, loginCallbackURL.String())
if err != nil {
return nil, errors.WithStack(err)
}
postLoginRedirectURL, err := a.mergeURL(originalURL, originalURL.Path, options.OIDC.PublicBaseURL, true)
if err != nil {
return nil, errors.WithStack(err)
}
idToken, err := client.Authenticate(w, r, sess, postLoginRedirectURL.String())
if err != nil {
if errors.Is(err, ErrLoginRequired) {
metricLoginRequestsTotal.With(prometheus.Labels{
metricLabelLayer: string(layer.Name),
metricLabelProxy: string(layer.Proxy),
}).Add(1)
return nil, errors.WithStack(authn.ErrSkipRequest)
}
return nil, errors.WithStack(err)
}
user, err := a.toUser(originalURL, idToken, layer.Proxy, layer.Name, options, sess)
if err != nil {
return nil, errors.WithStack(err)
}
return user, nil
}
type claims struct {
Issuer string `json:"iss"`
Subject string `json:"sub"`
Expiration int64 `json:"exp"`
IssuedAt int64 `json:"iat"`
AuthTime int64 `json:"auth_time"`
Nonce string `json:"nonce"`
ACR string `json:"acr"`
AMR string `json:"amr"`
AZP string `json:"amp"`
Others map[string]any `json:"-"`
}
func (c claims) AsAttrs() map[string]any {
attrs := make(map[string]any)
for key, val := range c.Others {
if val != nil {
attrs["claim_"+key] = val
}
}
attrs["claim_iss"] = c.Issuer
attrs["claim_sub"] = c.Subject
attrs["claim_exp"] = c.Expiration
attrs["claim_iat"] = c.IssuedAt
if c.AuthTime != 0 {
attrs["claim_auth_time"] = c.AuthTime
}
if c.Nonce != "" {
attrs["claim_nonce"] = c.Nonce
}
if c.ACR != "" {
attrs["claim_arc"] = c.ACR
}
if c.AMR != "" {
attrs["claim_amr"] = c.AMR
}
if c.AZP != "" {
attrs["claim_azp"] = c.AZP
}
return attrs
}
func (a *Authenticator) toUser(originalURL *url.URL, idToken *oidc.IDToken, proxyName store.ProxyName, layerName store.LayerName, options *LayerOptions, sess *sessions.Session) (*authn.User, error) {
var claims claims
if err := idToken.Claims(&claims); err != nil {
return nil, errors.WithStack(err)
}
if err := idToken.Claims(&claims.Others); err != nil {
return nil, errors.WithStack(err)
}
attrs := claims.AsAttrs()
logoutURL, err := a.getLogoutURL(originalURL, proxyName, layerName, options)
if err != nil {
return nil, errors.WithStack(err)
}
attrs["logout_url"] = logoutURL.String()
if accessToken, exists := sess.Values[sessionKeyAccessToken]; exists && accessToken != nil {
attrs["access_token"] = accessToken
}
if refreshToken, exists := sess.Values[sessionKeyRefreshToken]; exists && refreshToken != nil {
attrs["refresh_token"] = refreshToken
}
if tokenExpiry, exists := sess.Values[sessionKeyTokenExpiry]; exists && tokenExpiry != nil {
attrs["token_expiry"] = tokenExpiry
}
user := authn.NewUser(idToken.Subject, attrs)
return user, nil
}
func (a *Authenticator) getLoginCallbackURL(originalURL *url.URL, proxyName store.ProxyName, layerName store.LayerName, options *LayerOptions) (*url.URL, error) {
path, err := a.templatize(options.OIDC.LoginCallbackPath, proxyName, layerName)
if err != nil {
return nil, errors.WithStack(err)
}
merged, err := a.mergeURL(originalURL, path, options.OIDC.PublicBaseURL, false)
if err != nil {
return nil, errors.WithStack(err)
}
return merged, nil
}
func (a *Authenticator) getLogoutURL(originalURL *url.URL, proxyName store.ProxyName, layerName store.LayerName, options *LayerOptions) (*url.URL, error) {
path, err := a.templatize(options.OIDC.LogoutPath, proxyName, layerName)
if err != nil {
return nil, errors.WithStack(err)
}
merged, err := a.mergeURL(originalURL, path, options.OIDC.PublicBaseURL, true)
if err != nil {
return nil, errors.WithStack(err)
}
return merged, nil
}
func (a *Authenticator) mergeURL(base *url.URL, path string, overlay string, withQuery bool) (*url.URL, error) {
merged := &url.URL{
Scheme: base.Scheme,
Host: base.Host,
Path: path,
}
if withQuery {
merged.RawQuery = base.RawQuery
}
if overlay != "" {
overlayURL, err := url.Parse(overlay)
if err != nil {
return nil, errors.WithStack(err)
}
merged.Scheme = overlayURL.Scheme
merged.Host = overlayURL.Host
merged.Path = overlayURL.Path + strings.TrimPrefix(path, "/")
for key, values := range overlayURL.Query() {
query := merged.Query()
for _, v := range values {
query.Add(key, v)
}
merged.RawQuery = query.Encode()
}
}
return merged, nil
}
func (a *Authenticator) templatize(rawTemplate string, proxyName store.ProxyName, layerName store.LayerName) (string, error) {
tmpl, err := template.New("").Parse(rawTemplate)
if err != nil {
return "", errors.WithStack(err)
}
var raw bytes.Buffer
err = tmpl.Execute(&raw, struct {
ProxyName store.ProxyName
LayerName store.LayerName
}{
ProxyName: proxyName,
LayerName: layerName,
})
if err != nil {
return "", errors.WithStack(err)
}
return raw.String(), nil
}
func (a *Authenticator) getClient(options *LayerOptions, redirectURL string) (*Client, error) {
ctx := context.Background()
transport := a.httpTransport.Clone()
if options.OIDC.TLSInsecureSkipVerify {
if transport.TLSClientConfig == nil {
transport.TLSClientConfig = &tls.Config{}
}
transport.TLSClientConfig.InsecureSkipVerify = true
}
httpClient := &http.Client{
Timeout: a.httpClientTimeout,
Transport: transport,
}
ctx = oidc.ClientContext(ctx, httpClient)
if options.OIDC.SkipIssuerVerification {
ctx = oidc.InsecureIssuerURLContext(ctx, options.OIDC.IssuerURL)
}
provider, err := oidc.NewProvider(ctx, options.OIDC.IssuerURL)
if err != nil {
return nil, errors.Wrap(err, "could not create oidc provider")
}
client := NewClient(
WithCredentials(options.OIDC.ClientID, options.OIDC.ClientSecret),
WithProvider(provider),
WithRedirectURL(redirectURL),
WithScopes(options.OIDC.Scopes...),
WithAuthParams(options.OIDC.AuthParams),
WithHTTPClient(httpClient),
)
return client, nil
}
func (a *Authenticator) getCookieName(cookieName string, layerName store.LayerName) string {
return fmt.Sprintf("%s_%s", cookieName, layerName)
}
var (
_ authn.PreAuthentication = &Authenticator{}
_ authn.Authenticator = &Authenticator{}
)