Don't return value for {remote} placeholder in early dataearly-data

1 files changed, 8 insertions, 0 deletions

diff --git a/modules/caddyhttp/replacer.go b/modules/caddyhttp/replacer.go
index 1cf3ec474..2c0f32357 100644
--- a/modules/caddyhttp/replacer.go
+++ b/modules/caddyhttp/replacer.go
@@ -142,8 +142,16 @@ func addHTTPVarsToReplacer(repl *caddy.Replacer, req *http.Request, w http.Respo
 				}
 				return port, true
 			case "http.request.remote":
+				if req.TLS != nil && !req.TLS.HandshakeComplete {
+					// without a complete handshake (QUIC "early data") we can't trust the remote IP address to not be spoofed
+					return nil, true
+				}
 				return req.RemoteAddr, true
 			case "http.request.remote.host":
+				if req.TLS != nil && !req.TLS.HandshakeComplete {
+					// without a complete handshake (QUIC "early data") we can't trust the remote IP address to not be spoofed
+					return nil, true
+				}
 				host, _, err := net.SplitHostPort(req.RemoteAddr)
 				if err != nil {
 					// req.RemoteAddr is host:port for tcp and udp sockets and /unix/socket.path