Merge pull request #105143 from aojea/netexec_optional_listen

agnhost: allow to disable udp listener on netexec

test/images/agnhost/README.md

@@ -417,6 +417,8 @@ It will also start a UDP server on the indicated UDP port that responds to the f
 - `echo <msg>`: Returns the given `<msg>`
 - `clientip`: Returns the request's IP address
 
+The UDP server can be disabled by setting `--udp-port -1`.
+
 Additionally, if (and only if) `--sctp-port` is passed, it will start an SCTP server on that port,
 responding to the same commands as the UDP server.
 

test/images/agnhost/VERSION

@@ -1 +1 @@
-2.33
+2.34

test/images/agnhost/netexec/netexec.go

@@ -106,12 +106,14 @@ will be upgraded to HTTPS. The image has default, "localhost"-based cert/privkey
 If "--http-override" is set, the HTTP(S) server will always serve the override path & options,
 ignoring the request URL.
 
-It will also start a UDP server on the indicated UDP port that responds to the following commands:
+It will also start a UDP server on the indicated UDP port and addresses that responds to the following commands:
 
 - "hostname": Returns the server's hostname
 - "echo <msg>": Returns the given <msg>
 - "clientip": Returns the request's IP address
 
+The UDP server can be disabled by setting --udp-port to -1.
+
 Additionally, if (and only if) --sctp-port is passed, it will start an SCTP server on that port,
 responding to the same commands as the UDP server.
 `,
@@ -168,14 +170,19 @@ func main(cmd *cobra.Command, args []string) {
 		addRoutes(http.DefaultServeMux, exitCh)
 	}
 
-	udpBindTo, err := parseAddresses(udpListenAddresses)
-	if err != nil {
-		log.Fatal(err)
+	// UDP server
+	if udpPort != -1 {
+		udpBindTo, err := parseAddresses(udpListenAddresses)
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		for _, address := range udpBindTo {
+			go startUDPServer(address, udpPort)
+		}
 	}
 
-	for _, address := range udpBindTo {
-		go startUDPServer(address, udpPort)
-	}
+	// SCTP server
 	if sctpPort != -1 {
 		go startSCTPServer(sctpPort)
 	}