handshake.go

/*
Copyright 2020 The Board of Trustees of The Leland Stanford Junior University

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package lzr

import (
	//"fmt"
	"strings"
)

var (

	handshakes map[string]Handshake
	fingerprintMap  map[string]int
)
type Handshake interface {

    //get Data to send in first packet
    GetData( dst string ) []byte
	//verify the protocol from response
	Verify( data string)  string

}

func AddHandshake( name string, h Handshake ) {

	handshakes[ name ] = h

}

func GetHandshake( name string ) (Handshake,bool) {
	h, ok := handshakes[name]
	return h,ok
}

// implement a hiearchy where when responses match
// for two fingerprints, we choose the more specific one
// e.g., protocols implemented on http
func hiearchizeFingerprint( fingerprint string ) string {


	// prioritize for the handshake being sent
	// or for handshake which was asked to be prioritized
	// so if scanning for http ipp will return as http
	// but if scanning for ipp then http+ipp will return ipp

	req_handshakes := GetAllHandshakes()
	for  _, h := range req_handshakes {
		if strings.Contains( fingerprint, h ) {
			return h
		}
	}


	if strings.Contains( fingerprint, "ipp" ) {
		return "ipp"
	} else if strings.Contains( fingerprint, "kubernetes") {
		return "kubernetes"
	} else if (strings.Contains( fingerprint, "dns") &&
		strings.Contains( fingerprint, "http")) {
		return "http"
	}else if (strings.Contains( fingerprint, "ssh") &&
		strings.Contains( fingerprint, "http")) {
		return "http"
	}else if (strings.Contains( fingerprint, "ftp") &&
		strings.Contains( fingerprint, "http")) {
		return "http"
	}else if (strings.Contains( fingerprint, "ftp") &&
		strings.Contains( fingerprint, "ssh")) {
		return "ssh"
	//probs tls with HTTPS text
	} else if (strings.Contains( fingerprint, "tls") &&
		strings.Contains( fingerprint, "http")) {
		return "tls"
	} else {
		//fmt.Println("WARNING: NEW MULTI-FINGERPRINT:", fingerprint)
		return fingerprint
	}

}

func fingerprintResponse( data string ) string {
	fingerprint := ""
	tfingerprint := ""
	multiprint := false
	for _, hand := range handshakes {
		tfingerprint = hand.Verify( data )
		if tfingerprint != "" {
			//concat fingerprints together 
			if fingerprint == "" {
				fingerprint += tfingerprint
			} else {
				multiprint = true
				fingerprint += ("-" + tfingerprint)
			}

		}
	}
	if multiprint {
		fingerprint = hiearchizeFingerprint( fingerprint )
	}
	if fingerprint == "" {
		fingerprint = "unknown"
	}
	fingerprintMap[fingerprint] += 1
	return fingerprint
}

func GetFingerprints() map[string]int {
	return fingerprintMap
}

func init() {
	handshakes = make( map[string]Handshake )
	fingerprintMap = make( map[string]int )
}