Fix sigsev when conLdap.Close() after connection was droped remotely

LICENSE

@@ -0,0 +1,30 @@
+Copyright (C) 2020, yo000 <johan@nosd.in>
+
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions
+are met:
+
+- Redistributions of source code must retain the above copyright notice,
+  this list of conditions and the following disclaimer.
+- Redistributions in binary form must reproduce the above copyright notice,
+  this list of conditions and the following disclaimer in the documentation
+  and/or other materials provided with the distribution.
+- Neither the name of the Mumble Developers nor the names of its
+  contributors may be used to endorse or promote products derived from this
+  software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+`AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR
+CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+

mynettcptable.conf.sample

@@ -5,3 +5,5 @@ ldapUser cn=mynettcptable,ou=services,dc=example,dc=org
 ldapPass here_lies_the_password
 # networks cache refresh interval
 refresh 300
+# Inactive connection timeout
+timeout 30

mynettcptable.go

@@ -7,49 +7,49 @@
 package main
 
 import (
-	"os"
 	"fmt"
 	"net"
-//	"log"
+	"os"
+	//	"log"
+	"errors"
 	"flag"
+	"log/syslog"
+	"strings"
 	"sync"
 	"time"
-	"errors"
-	"strings"
-	"log/syslog"
 
-	"github.com/tabalt/pidfile"
 	"github.com/go-ldap/ldap/v3"
 	"github.com/peterbourgon/ff"
 	"github.com/sirupsen/logrus"
 	lSyslog "github.com/sirupsen/logrus/hooks/syslog"
+	"github.com/tabalt/pidfile"
 )
 
 const (
-	version = "1.0.0-rc"
+	version = "1.0.1"
 )
 
 var (
-	logstream   	*logrus.Logger
+	logstream       *logrus.Logger
-	conLdap     	*ldap.Conn
+	conLdap         *ldap.Conn
-	mutex       	sync.Mutex
+	mutex           sync.Mutex
-	logTo       	*string
+	logTo           *string
-	logLevel       	*string
+	logLevel        *string
-	listen      	*string
+	listen          *string
-	ldapURL     	*string
+	ldapURL         *string
-	ldapBaseDN  	*string
+	ldapBaseDN      *string
-	ldapUser    	*string
+	ldapUser        *string
-	ldapPass    	*string
+	ldapPass        *string
-	refreshInterval	*int
+	refreshInterval *int
-	pidFilePath 	*string
+	pidFilePath     *string
-	timeout     	*int
+	timeout         *int
 
-	netCache		[]NoAuthNet
+	netCache []NoAuthNet
 )
 
 type NoAuthNet struct {
-	Net					*net.IPNet
+	Net     *net.IPNet
-	Present				bool
+	Present bool
 }
 
 // Test if a net is present in cache, and set "Present" flag to true
@@ -95,7 +95,6 @@ func unsetNetCachePresentFlag() {
 	}
 }
 
-
 func buildNetCacheFromIPNetwork(conLdap *ldap.Conn) error {
 	attribute := "ipNetworkNumber"
 
@@ -117,17 +116,13 @@ func buildNetCacheFromIPNetwork(conLdap *ldap.Conn) error {
 			logstream.Info(fmt.Sprintf("Error searching into LDAP: Attribute %s not found for entry %s\n", attribute, r))
 			continue
 		} else {
-			// Explode the network to individual IPs
-			// 1: Verify format : Either CIDR, or netmask is in ipNetworkMask (do we want to support this?)
-			// 2: n := iplib.NewNet4(net.ParseIP("192.168.0.0"), 16)
-			//    n.Enumerate(
 			_, ipnet, err := net.ParseCIDR(r.Attributes[0].Values[0])
 			if err != nil {
 				logstream.Info(err.Error())
 				continue
 			}
 			if false == checkNetCacheContainsAndFlag(ipnet) {
-				netCache = append(netCache, NoAuthNet{ Net: ipnet, Present: true })
+				netCache = append(netCache, NoAuthNet{Net: ipnet, Present: true})
 			}
 		}
 	}
@@ -143,7 +138,6 @@ func buildNetCacheFromIPNetwork(conLdap *ldap.Conn) error {
 	return nil
 }
 
-
 func isIPContainedInNetCache(string_ip string) (bool, error) {
 	ip := net.ParseIP(string_ip)
 	if ip == nil {
@@ -183,8 +177,6 @@ func handleConnection(connClt net.Conn, conLdap *ldap.Conn) {
 			if err.Error() != "EOF" && !strings.HasSuffix(err.Error(), "i/o timeout") {
 				logstream.Errorf("Error reading connection: %v\n", err.Error())
 			}
-			//sendResponse(connClt, err.Error(), 500)
-			//continue
 			return
 		}
 
@@ -214,11 +206,11 @@ func handleConnection(connClt net.Conn, conLdap *ldap.Conn) {
 		// "set loglevel level" sent on listening port will set current loglevel
 		if readlen > 14 && strings.EqualFold(string(buf[:12]), "set loglevel") {
 			logstream.Infof("Received \"%s\" instruction from %s", string(buf[:readlen-1]), connClt.RemoteAddr().String())
-			level, err := logrus.ParseLevel(string(buf[13:readlen-1]))
+			level, err := logrus.ParseLevel(string(buf[13 : readlen-1]))
-		    if err != nil {
+			if err != nil {
 				sendResponse(connClt, fmt.Sprintf("Invalid log level: %s", string(buf[13:readlen-1])), 500)
-		    } else {
+			} else {
-		        logstream.Level = level
+				logstream.Level = level
 				sendResponse(connClt, "loglevel set", 200)
 			}
 			continue
@@ -230,12 +222,17 @@ func handleConnection(connClt net.Conn, conLdap *ldap.Conn) {
 			sendResponse(connClt, fmt.Sprintf("Invalid request: %s", buf[:readlen-1]), 500)
 			continue
 		}
-		ip := string(buf[4:readlen-1])
+		ip := string(buf[4 : readlen-1])
 
 		// First query netCache built with ipNetworkNumber
 		res, err := isIPContainedInNetCache(ip)
 		if err != nil {
-			logstream.Error(err.Error())
+			if strings.EqualFold(err.Error(), fmt.Sprintf("Invalid IP: %s", ip)) {
+				// We don't want those msg to pollute logs
+				logstream.Info(err.Error())
+			} else {
+				logstream.Error(err.Error())
+			}
 			sendResponse(connClt, err.Error(), 500)
 			continue
 		}
@@ -287,7 +284,11 @@ func searchLdap(searchReq *ldap.SearchRequest, attempt int) (*ldap.SearchResult,
 	if err != nil && strings.HasSuffix(err.Error(), "ldap: connection closed") {
 		logstream.Error("LDAP connection closed, retrying")
 		mutex.Lock()
-		conLdap.Close()
+		// 16/01/2023: panic: runtime error: invalid memory address or nil pointer dereference
+		// probably bc connection is already closed
+		if conLdap != nil {
+			conLdap.Close()
+		}
 		conLdap, err = connectLdap()
 		mutex.Unlock()
 		if err != nil {
@@ -305,12 +306,12 @@ func connectLdap() (*ldap.Conn, error) {
 	conLdap, err = ldap.DialURL(*ldapURL)
 	if err != nil {
 		logstream.Errorf("Error dialing LDAP on %s: %v\n", *ldapURL, err)
-		return conLdap, err
+		return nil, err
 	}
 	err = conLdap.Bind(*ldapUser, *ldapPass)
 	if err != nil {
-		logstream.Errorf("Error binding LDAP: ", err)
+		logstream.Errorf("Error binding LDAP: %s", err)
-		return conLdap, err
+		return nil, err
 	}
 	return conLdap, err
 }
@@ -357,7 +358,7 @@ func main() {
 	ldapBaseDN = fs.String("ldapDN", "", "LDAP base DN (also via LDAPDN env var)")
 	ldapUser = fs.String("ldapUser", "", "LDAP user DN (also via LDAPUSER env var)")
 	ldapPass = fs.String("ldapPass", "", "LDAP user password (also via LDAPPASS env var)")
-	pidFilePath = fs.String("pidfile", "/var/run/mynettcptable/mynettcptable.pid", "PID File (also via PIDFILE env var)")
+	pidFilePath = fs.String("pidfile", "", "PID File (also via PIDFILE env var). Creates pidfile only if defined")
 	refreshInterval = fs.Int("refresh", 300, "Net cache update interval in seconds")
 	timeout = fs.Int("timeout", 5, "timeout in seconds")
 	_ = fs.String("config", "", "config file (optional)")
@@ -391,17 +392,17 @@ func main() {
 	if strings.EqualFold(*logTo, "syslog") {
 		// level != priority
 		prio := syslog.LOG_MAIL
-		switch (*logLevel) {
+		switch *logLevel {
-			case "fatal":
+		case "fatal":
-				prio += syslog.LOG_CRIT
+			prio += syslog.LOG_CRIT
-			case "error":
+		case "error":
-				prio += syslog.LOG_ERR
+			prio += syslog.LOG_ERR
-			case "warn":
+		case "warn":
-				prio += syslog.LOG_WARNING
+			prio += syslog.LOG_WARNING
-			case "info":
+		case "info":
-				prio += syslog.LOG_INFO
+			prio += syslog.LOG_INFO
-			case "debug":
+		case "debug":
-				prio += syslog.LOG_DEBUG
+			prio += syslog.LOG_DEBUG
 		}
 		hook, err := lSyslog.NewSyslogHook("", "", prio, "mynettcptable")
 		if err != nil {
@@ -411,15 +412,14 @@ func main() {
 		logstream.Hooks.Add(hook)
 	}
 
-	if pid, err := pidfile.Create(*pidFilePath); err != nil {
+	if len(*pidFilePath) > 0 {
-		logstream.Fatal(err)
+		if pid, err := pidfile.Create(*pidFilePath); err != nil {
-	} else {
+			logstream.Fatal(err)
-		defer pid.Clear()
+		} else {
+			defer pid.Clear()
+		}
 	}
 
-	//defer logstream.Close()
-
 	logstream.Infof("Start listening for incoming connections on %s\n", *listen)
 	run()
 }
-