From cb9cf1ab36b6f971423011d6bb6920bd78b81ca7 Mon Sep 17 00:00:00 2001
From: yo <johan@nosd.in>
Date: Thu, 11 Feb 2021 14:43:16 +0100
Subject: [PATCH] BUFIX : Check MX format with regex instead of old split
 method

---
 mxrouter.go | 25 ++++++++++++++++++-------
 1 file changed, 18 insertions(+), 7 deletions(-)

diff --git a/mxrouter.go b/mxrouter.go
index 6febc49..3b698d5 100644
--- a/mxrouter.go
+++ b/mxrouter.go
@@ -10,6 +10,7 @@
 // Use a single LDAP connection protected by a mutex
 //
 // v0.9.6 : add PID file
+// v0.9.7.2 : Check MX format with regex
 //
 
 package main
@@ -21,6 +22,7 @@ import (
 	"log/syslog"
 	"net"
 	"os"
+	"regexp"
 	"strings"
 	"sync"
 	"time"
@@ -31,7 +33,10 @@ import (
 )
 
 const (
-	version = "0.9.7.1"
+	version = "0.9.7.2"
+	// Match le nom de domaine, soit les 2 dernieres chaines separees par un point.
+	//  Peut aussi terminer par un point (Ex: srv.domaine.com. => domaine.com)
+	DomainRegexpFormat = `([0-9A-Za-z\-]*)\.([0-9A-Za-z\-]*)(?:\.)?$`
 )
 
 var (
@@ -85,8 +90,11 @@ func sendResponse(con net.Conn, respMsg string, respCode int) error {
 func handleConnection(connClt net.Conn, conLdap *ldap.Conn) {
 	var s string
 	var mxdom string
+
 	buf := make([]byte, 1024)
 
+	re := regexp.MustCompile(DomainRegexpFormat)
+
 	// Close connection when this function ends
 	defer func() {
 		logstream.Debug("Closing connection")
@@ -130,13 +138,16 @@ func handleConnection(connClt net.Conn, conLdap *ldap.Conn) {
 				continue
 			}
 
-			mxslic := strings.Split(mxs[0].Host, ".")
-			// les MXs terminent par '.', on le retire
-			if mxs[0].Host[len(mxs[0].Host)-1] == '.' {
-				mxdom = strings.Join(mxslic[len(mxslic)-3:len(mxslic)-1], ".")
-			} else {
-				mxdom = strings.Join(mxslic[len(mxslic)-2:len(mxslic)], ".")
+			// On recuperer le nom de domaine de 1er niveau
+			group := re.FindSubmatch([]byte(mxs[0].Host))
+			if len(group) < 3 || len(group[2]) == 0 {
+				logstream.Err(fmt.Sprintln("MX format incorrect: ", mxs[0].Host))
+				w
+				s := fmt.Sprintf("MX format incorrect: %s", err.Error())
+				sendResponse(connClt, s, 500)
+				continue
 			}
+			mxdom = string(group[1]) + "." + string(group[2])
 
 			filter := fmt.Sprintf("(dc=%s)", ldap.EscapeFilter(mxdom))
 			searchReq := ldap.NewSearchRequest(*ldapBaseDN, ldap.ScopeWholeSubtree, 0, 0, 0,