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authentik/internal/outpost/proxyv2/application/mode_forward.go
Jens Langhammer f10b57ba0b outposts/proxy: handle redirect loop in start handler, show error message
Signed-off-by: Jens Langhammer <jens.langhammer@beryju.org>
2021-12-21 10:07:08 +01:00

93 lines
3 KiB
Go

package application
import (
"fmt"
"net/http"
"net/url"
"goauthentik.io/api"
"goauthentik.io/internal/outpost/proxyv2/constants"
"goauthentik.io/internal/utils/web"
)
func (a *Application) configureForward() error {
a.mux.HandleFunc("/akprox/auth", func(rw http.ResponseWriter, r *http.Request) {
if _, ok := r.URL.Query()["traefik"]; ok {
a.forwardHandleTraefik(rw, r)
return
}
a.forwardHandleNginx(rw, r)
})
a.mux.HandleFunc("/akprox/auth/traefik", a.forwardHandleTraefik)
a.mux.HandleFunc("/akprox/auth/nginx", a.forwardHandleNginx)
return nil
}
func (a *Application) forwardHandleTraefik(rw http.ResponseWriter, r *http.Request) {
claims, err := a.getClaims(r)
if claims != nil && err == nil {
a.addHeaders(rw.Header(), claims)
rw.Header().Set("User-Agent", r.Header.Get("User-Agent"))
a.log.WithField("headers", rw.Header()).Trace("headers written to forward_auth")
return
} else if claims == nil && a.IsAllowlisted(r) {
a.log.Trace("path can be accessed without authentication")
return
}
host := ""
s, _ := a.sessions.Get(r, constants.SeesionName)
// Optional suffix, which is appended to the URL
if *a.proxyConfig.Mode == api.PROXYMODE_FORWARD_SINGLE {
host = web.GetHost(r)
} else if *a.proxyConfig.Mode == api.PROXYMODE_FORWARD_DOMAIN {
eh, _ := url.Parse(a.proxyConfig.ExternalHost)
host = eh.Host
}
// set the redirect flag to the current URL we have, since we redirect
// to a (possibly) different domain, but we want to be redirected back
// to the application
// see https://doc.traefik.io/traefik/middlewares/forwardauth/
// X-Forwarded-Uri is only the path, so we need to build the entire URL
s.Values[constants.SessionRedirect] = fmt.Sprintf(
"%s://%s%s",
r.Header.Get("X-Forwarded-Proto"),
r.Header.Get("X-Forwarded-Host"),
r.Header.Get("X-Forwarded-Uri"),
)
if r.Header.Get("X-Forwarded-Uri") == "/akprox/start" {
a.log.Info("Detected potential redirect loop")
if val, ok := s.Values[constants.SessionLoopDetection]; !ok {
s.Values[constants.SessionLoopDetection] = 1
} else {
s.Values[constants.SessionLoopDetection] = val.(int) + 1
}
}
err = s.Save(r, rw)
if err != nil {
a.log.WithError(err).Warning("failed to save session before redirect")
}
proto := r.Header.Get("X-Forwarded-Proto")
if proto != "" {
proto = proto + ":"
}
rdFinal := fmt.Sprintf("%s//%s%s", proto, host, "/akprox/start")
a.log.WithField("url", rdFinal).Debug("Redirecting to login")
http.Redirect(rw, r, rdFinal, http.StatusTemporaryRedirect)
}
func (a *Application) forwardHandleNginx(rw http.ResponseWriter, r *http.Request) {
claims, err := a.getClaims(r)
if claims != nil && err == nil {
a.addHeaders(rw.Header(), claims)
rw.Header().Set("User-Agent", r.Header.Get("User-Agent"))
rw.WriteHeader(200)
a.log.WithField("headers", rw.Header()).Trace("headers written to forward_auth")
return
} else if claims == nil && a.IsAllowlisted(r) {
a.log.Trace("path can be accessed without authentication")
return
}
http.Error(rw, "unauthorized request", http.StatusUnauthorized)
}