From 994b5b9a0a0e67992bb5db03dfe5c13a3520f139 Mon Sep 17 00:00:00 2001
From: Mechiel Lukkien <mechiel@ueber.net>
Date: Tue, 28 Feb 2023 20:40:52 +0100
Subject: [PATCH] fix serving mta-sts policy files

i broke it 3 days ago when adding support for serving it through external reverse proxy.

report by mteege, thanks!
---
 http/mtasts.go | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/http/mtasts.go b/http/mtasts.go
index b5c5585..6f5963a 100644
--- a/http/mtasts.go
+++ b/http/mtasts.go
@@ -15,14 +15,16 @@ import (
 func mtastsPolicyHandle(w http.ResponseWriter, r *http.Request) {
 	log := xlog.WithCid(mox.Cid())
 
-	if !strings.HasPrefix(r.Host, "mta-sts.") {
+	host := strings.ToLower(r.Host)
+	if !strings.HasPrefix(host, "mta-sts.") {
 		http.NotFound(w, r)
 		return
 	}
-	host, _, err := net.SplitHostPort(strings.TrimPrefix(r.Host, "mta-sts."))
-	if err != nil {
-		http.NotFound(w, r)
-		return
+	host = strings.TrimPrefix(host, "mta-sts.")
+	nhost, _, err := net.SplitHostPort(host)
+	if err == nil {
+		// Only relevant for when host has a port.
+		host = nhost
 	}
 	domain, err := dns.ParseDomain(host)
 	if err != nil {