root: check remote IP for proxy protocol same as HTTP/etc (cherry-pick #12094) (#12097)

root: check remote IP for proxy protocol same as HTTP/etc (#12094)

Signed-off-by: Jens Langhammer <jens@goauthentik.io>
Co-authored-by: Jens L. <jens@goauthentik.io>

internal/outpost/ldap/ldap.go

@@ -65,7 +65,7 @@ func (ls *LDAPServer) StartLDAPServer() error {
 		ls.log.WithField("listen", listen).WithError(err).Warning("Failed to listen (SSL)")
 		return err
 	}
-	proxyListener := &proxyproto.Listener{Listener: ln}
+	proxyListener := &proxyproto.Listener{Listener: ln, ConnPolicy: utils.GetProxyConnectionPolicy()}
 	defer proxyListener.Close()
 
 	ls.log.WithField("listen", listen).Info("Starting LDAP server")

internal/outpost/ldap/ldap_tls.go

@@ -48,7 +48,7 @@ func (ls *LDAPServer) StartLDAPTLSServer() error {
 		return err
 	}
 
-	proxyListener := &proxyproto.Listener{Listener: ln}
+	proxyListener := &proxyproto.Listener{Listener: ln, ConnPolicy: utils.GetProxyConnectionPolicy()}
 	defer proxyListener.Close()
 
 	tln := tls.NewListener(proxyListener, tlsConfig)

internal/outpost/proxyv2/proxyv2.go

@@ -129,7 +129,7 @@ func (ps *ProxyServer) ServeHTTP() {
 		ps.log.WithField("listen", listenAddress).WithError(err).Warning("Failed to listen")
 		return
 	}
-	proxyListener := &proxyproto.Listener{Listener: listener}
+	proxyListener := &proxyproto.Listener{Listener: listener, ConnPolicy: utils.GetProxyConnectionPolicy()}
 	defer proxyListener.Close()
 
 	ps.log.WithField("listen", listenAddress).Info("Starting HTTP server")
@@ -148,7 +148,7 @@ func (ps *ProxyServer) ServeHTTPS() {
 		ps.log.WithError(err).Warning("Failed to listen (TLS)")
 		return
 	}
-	proxyListener := &proxyproto.Listener{Listener: web.TCPKeepAliveListener{TCPListener: ln.(*net.TCPListener)}}
+	proxyListener := &proxyproto.Listener{Listener: web.TCPKeepAliveListener{TCPListener: ln.(*net.TCPListener)}, ConnPolicy: utils.GetProxyConnectionPolicy()}
 	defer proxyListener.Close()
 
 	tlsListener := tls.NewListener(proxyListener, tlsConfig)

internal/utils/proxy.go

@@ -0,0 +1,34 @@
+package utils
+
+import (
+	"net"
+
+	"github.com/pires/go-proxyproto"
+	log "github.com/sirupsen/logrus"
+	"goauthentik.io/internal/config"
+)
+
+func GetProxyConnectionPolicy() proxyproto.ConnPolicyFunc {
+	nets := []*net.IPNet{}
+	for _, rn := range config.Get().Listen.TrustedProxyCIDRs {
+		_, cidr, err := net.ParseCIDR(rn)
+		if err != nil {
+			continue
+		}
+		nets = append(nets, cidr)
+	}
+	return func(connPolicyOptions proxyproto.ConnPolicyOptions) (proxyproto.Policy, error) {
+		host, _, err := net.SplitHostPort(connPolicyOptions.Upstream.String())
+		if err == nil {
+			// remoteAddr will be nil if the IP cannot be parsed
+			remoteAddr := net.ParseIP(host)
+			for _, allowedCidr := range nets {
+				if remoteAddr != nil && allowedCidr.Contains(remoteAddr) {
+					log.WithField("remoteAddr", remoteAddr).WithField("cidr", allowedCidr.String()).Trace("Using remote IP from proxy protocol")
+					return proxyproto.USE, nil
+				}
+			}
+		}
+		return proxyproto.SKIP, nil
+	}
+}

internal/web/web.go

@@ -19,6 +19,7 @@ import (
 	"goauthentik.io/internal/config"
 	"goauthentik.io/internal/gounicorn"
 	"goauthentik.io/internal/outpost/proxyv2"
+	"goauthentik.io/internal/utils"
 	"goauthentik.io/internal/utils/web"
 	"goauthentik.io/internal/web/brand_tls"
 )
@@ -149,7 +150,7 @@ func (ws *WebServer) listenPlain() {
 		ws.log.WithError(err).Warning("failed to listen")
 		return
 	}
-	proxyListener := &proxyproto.Listener{Listener: ln}
+	proxyListener := &proxyproto.Listener{Listener: ln, ConnPolicy: utils.GetProxyConnectionPolicy()}
 	defer proxyListener.Close()
 
 	ws.log.WithField("listen", config.Get().Listen.HTTP).Info("Starting HTTP server")

internal/web/web_tls.go

@@ -45,7 +45,7 @@ func (ws *WebServer) listenTLS() {
 		ws.log.WithError(err).Warning("failed to listen (TLS)")
 		return
 	}
-	proxyListener := &proxyproto.Listener{Listener: web.TCPKeepAliveListener{TCPListener: ln.(*net.TCPListener)}}
+	proxyListener := &proxyproto.Listener{Listener: web.TCPKeepAliveListener{TCPListener: ln.(*net.TCPListener)}, ConnPolicy: utils.GetProxyConnectionPolicy()}
 	defer proxyListener.Close()
 
 	tlsListener := tls.NewListener(proxyListener, tlsConfig)