code-boxx/0-PHP-WEBAUTHN.MD

## 0-PHP-WEBAUTHN.MD

      
    Raw
  

              0-PHP-WEBAUTHN.MD
            
          
    SIMPLE PHP WEBAUTHN

https://code-boxx.com/simple-php-webauthn/
NOTES


Change $rp to your own in 3-init.php.
Run composer require lbuchs/webauthn to download the PHP Web Authn Library

LICENSE

Copyright by Code Boxx
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

  
## 1-demo.html
<!DOCTYPE html>
<html>
  <head>
    <title>PHP WebAuthn Demo</title>
    <script src="2-demo.js"></script>
  </head>
  <body>
    <button onclick="register.a()">Register</button>
    <button onclick="validate.a()">Validate</button>
  </body>
</html>

## 2-demo.js
// (A) HELPER FUNCTIONS
var helper = {
  // (A1) ARRAY BUFFER TO BASE 64
  atb : b => {
    let u = new Uint8Array(b), s = "";
    for (let i=0; i<u.byteLength; i++) { s += String.fromCharCode(u[i]); }
    return btoa(s);
  },

  // (A2) BASE 64 TO ARRAY BUFFER
  bta : o => {
    let pre = "=?BINARY?B?", suf = "?=";
    for (let k in o) { if (typeof o[k] == "string") {
      let s = o[k];
      if (s.substring(0, pre.length)==pre && s.substring(s.length - suf.length)==suf) {
        let b = window.atob(s.substring(pre.length, s.length - suf.length)),
            u = new Uint8Array(b.length);
        for (let i=0; i<b.length; i++) { u[i] = b.charCodeAt(i); }
        o[k] = u.buffer;
      }
    } else { helper.bta(o[k]); }}
  },

  // (A3) AJAX FETCH
  ajax : (url, data, after) => {
    let form = new FormData();
    for (let [k,v] of Object.entries(data)) { form.append(k,v); }
    fetch(url, { method: "POST", body: form })
    .then(res => res.text())
    .then(res => after(res))
    .catch(err => { alert("ERROR!"); console.error(err); });
  }
};

// (B) REGISTRATION
var register = {
  // (B1) CREATE CREDENTIALS
  a : () => helper.ajax("4-register.php", {
    phase : "a"
  }, async (res) => {
    try {
      res = JSON.parse(res);
      helper.bta(res);
      register.b(await navigator.credentials.create(res));
    } catch (e) { alert(res); console.error(e); }
  }),

  // (B2) SEND CREDENTIALS TO SERVER
  b : cred => helper.ajax("4-register.php", {
    phase : "b",
    transport : cred.response.getTransports ? cred.response.getTransports() : null,
    client : cred.response.clientDataJSON ? helper.atb(cred.response.clientDataJSON) : null,
    attest : cred.response.attestationObject ? helper.atb(cred.response.attestationObject) : null
  }, res => alert(res))
};

// (C) VALIDATION
var validate = {
  // (C1) GET CREDENTIALS
  a : () => helper.ajax("5-validate.php", {
    phase : "a"
  }, async (res) => {
    try {
      res = JSON.parse(res);
      helper.bta(res);
      validate.b(await navigator.credentials.get(res));
    } catch (e) { alert(res); console.error(e); }
  }),

  // (C2) SEND TO SERVER & VALIDATE
  b : cred => helper.ajax("5-validate.php", {
    phase : "b",
    id : cred.rawId ? helper.atb(cred.rawId) : null,
    client : cred.response.clientDataJSON  ? helper.atb(cred.response.clientDataJSON) : null,
    auth : cred.response.authenticatorData ? helper.atb(cred.response.authenticatorData) : null,
    sig : cred.response.signature ? helper.atb(cred.response.signature) : null,
    user : cred.response.userHandle ? helper.atb(cred.response.userHandle) : null
  }, res => alert(res))
};

## 3-init.php
<?php
// (A) RELYING PARTY - CHANGE TO YOUR OWN!
$rp = [
  "name" => "Code Boxx",
  "id" => "localhost"
];

// (B) DUMMY USER
$user = [
  "id" => "12345678",
  "name" => "jon@doe.com",
  "display" => "Jon Doe"
];
$saveto = "user.txt";

// (C) START SESSION & LOAD WEBAUTHN LIBRARY
session_start();
require "vendor/autoload.php";
$WebAuthn = new lbuchs\WebAuthn\WebAuthn($rp["name"], $rp["id"]);

## 4-register.php
<?php
// (A) INIT & CHECK
require "3-init.php";
if (file_exists($saveto)) { exit("User already registered"); }

switch ($_POST["phase"]) {
  // (B) REGISTRATION PART 1 - GET ARGUMENTS
  case "a":
    $args = $WebAuthn->getCreateArgs(
      \hex2bin($user["id"]), $user["name"], $user["display"],
      30, false, true
    );
    $_SESSION["challenge"] = ($WebAuthn->getChallenge())->getBinaryString();
    echo json_encode($args);
    break;

  // (C) REGISTRATION PART 2 - SAVE USER CREDENTIAL
  // should be saved in database, but we save into a file instead
  case "b":
    // (C1) VALIDATE & PROCESS
    try {
      $data = $WebAuthn->processCreate(
        base64_decode($_POST["client"]),
        base64_decode($_POST["attest"]),
        $_SESSION["challenge"],
        true, true, false
      );
    } catch (Exception $ex) { print_r($ex); exit; }

    // (C2) SAVE
    file_put_contents($saveto, serialize($data));
    echo "OK";
    break;
}

## 5-validate.php
<?php
// (A) INIT & CHECK
require "3-init.php";
if (!file_exists($saveto)) { exit("User is not registered"); }
$saved = unserialize(file_get_contents("user.txt"));

switch ($_POST["phase"]) {
  // (B) VALIDATION PART 1 - GET ARGUMENTS
  case "a":
    $args = $WebAuthn->getGetArgs([$saved->credentialId], 30);
    $_SESSION["challenge"] = ($WebAuthn->getChallenge())->getBinaryString();
    echo json_encode($args);
    break;

  // (C) VALIDATION PART 2 - CHECKS & PROCESS
  case "b":
    $id = base64_decode($_POST["id"]);
    if ($saved->credentialId !== $id) { exit("Invalid credentials"); }
    try {
      $WebAuthn->processGet(
        base64_decode($_POST["client"]),
        base64_decode($_POST["auth"]),
        base64_decode($_POST["sig"]),
        $saved->credentialPublicKey,
        $_SESSION["challenge"]
      );
      echo "OK";
      // DO WHATEVER IS REQUIRED AFTER VALIDATION
    } catch (Exception $ex) { print_r($ex); exit; }
    break;
}
	<!DOCTYPE html>
	<html>
	<head>
	<title>PHP WebAuthn Demo</title>
	<script src="2-demo.js"></script>
	</head>
	<body>
	<button onclick="register.a()">Register</button>
	<button onclick="validate.a()">Validate</button>
	</body>
	</html>
	// (A) HELPER FUNCTIONS
	var helper = {
	// (A1) ARRAY BUFFER TO BASE 64
	atb : b => {
	let u = new Uint8Array(b), s = "";
	for (let i=0; i<u.byteLength; i++) { s += String.fromCharCode(u[i]); }
	return btoa(s);
	},

	// (A2) BASE 64 TO ARRAY BUFFER
	bta : o => {
	let pre = "=?BINARY?B?", suf = "?=";
	for (let k in o) { if (typeof o[k] == "string") {
	let s = o[k];
	if (s.substring(0, pre.length)==pre && s.substring(s.length - suf.length)==suf) {
	let b = window.atob(s.substring(pre.length, s.length - suf.length)),
	u = new Uint8Array(b.length);
	for (let i=0; i<b.length; i++) { u[i] = b.charCodeAt(i); }
	o[k] = u.buffer;
	}
	} else { helper.bta(o[k]); }}
	},

	// (A3) AJAX FETCH
	ajax : (url, data, after) => {
	let form = new FormData();
	for (let [k,v] of Object.entries(data)) { form.append(k,v); }
	fetch(url, { method: "POST", body: form })
	.then(res => res.text())
	.then(res => after(res))
	.catch(err => { alert("ERROR!"); console.error(err); });
	}
	};

	// (B) REGISTRATION
	var register = {
	// (B1) CREATE CREDENTIALS
	a : () => helper.ajax("4-register.php", {
	phase : "a"
	}, async (res) => {
	try {
	res = JSON.parse(res);
	helper.bta(res);
	register.b(await navigator.credentials.create(res));
	} catch (e) { alert(res); console.error(e); }
	}),

	// (B2) SEND CREDENTIALS TO SERVER
	b : cred => helper.ajax("4-register.php", {
	phase : "b",
	transport : cred.response.getTransports ? cred.response.getTransports() : null,
	client : cred.response.clientDataJSON ? helper.atb(cred.response.clientDataJSON) : null,
	attest : cred.response.attestationObject ? helper.atb(cred.response.attestationObject) : null
	}, res => alert(res))
	};

	// (C) VALIDATION
	var validate = {
	// (C1) GET CREDENTIALS
	a : () => helper.ajax("5-validate.php", {
	phase : "a"
	}, async (res) => {
	try {
	res = JSON.parse(res);
	helper.bta(res);
	validate.b(await navigator.credentials.get(res));
	} catch (e) { alert(res); console.error(e); }
	}),

	// (C2) SEND TO SERVER & VALIDATE
	b : cred => helper.ajax("5-validate.php", {
	phase : "b",
	id : cred.rawId ? helper.atb(cred.rawId) : null,
	client : cred.response.clientDataJSON ? helper.atb(cred.response.clientDataJSON) : null,
	auth : cred.response.authenticatorData ? helper.atb(cred.response.authenticatorData) : null,
	sig : cred.response.signature ? helper.atb(cred.response.signature) : null,
	user : cred.response.userHandle ? helper.atb(cred.response.userHandle) : null
	}, res => alert(res))
	};
	<?php
	// (A) RELYING PARTY - CHANGE TO YOUR OWN!
	$rp = [
	"name" => "Code Boxx",
	"id" => "localhost"
	];

	// (B) DUMMY USER
	$user = [
	"id" => "12345678",
	"name" => "jon@doe.com",
	"display" => "Jon Doe"
	];
	$saveto = "user.txt";

	// (C) START SESSION & LOAD WEBAUTHN LIBRARY
	session_start();
	require "vendor/autoload.php";
	$WebAuthn = new lbuchs\WebAuthn\WebAuthn($rp["name"], $rp["id"]);
	<?php
	// (A) INIT & CHECK
	require "3-init.php";
	if (file_exists($saveto)) { exit("User already registered"); }

	switch ($_POST["phase"]) {
	// (B) REGISTRATION PART 1 - GET ARGUMENTS
	case "a":
	$args = $WebAuthn->getCreateArgs(
	\hex2bin($user["id"]), $user["name"], $user["display"],
	30, false, true
	);
	$_SESSION["challenge"] = ($WebAuthn->getChallenge())->getBinaryString();
	echo json_encode($args);
	break;

	// (C) REGISTRATION PART 2 - SAVE USER CREDENTIAL
	// should be saved in database, but we save into a file instead
	case "b":
	// (C1) VALIDATE & PROCESS
	try {
	$data = $WebAuthn->processCreate(
	base64_decode($_POST["client"]),
	base64_decode($_POST["attest"]),
	$_SESSION["challenge"],
	true, true, false
	);
	} catch (Exception $ex) { print_r($ex); exit; }

	// (C2) SAVE
	file_put_contents($saveto, serialize($data));
	echo "OK";
	break;
	}