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media/plg_system_webauthn/js/login.js

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+/**
+ * @package     Joomla.Plugin
+ * @subpackage  System.webauthn
+ *
+ * @copyright   (C) 2020 Open Source Matters, Inc. <https://www.joomla.org>
+ * @license     GNU General Public License version 2 or later; see LICENSE.txt
+ */
+
+window.Joomla = window.Joomla || {};
+((Joomla, document) => {
+
+  /**
+   * Converts a simple object containing query string parameters to a single, escaped query string.
+   * This method is a necessary evil since Joomla.request can only accept data as a string.
+   *
+   * @param    object   {object}  A plain object containing the query parameters to pass
+   * @param    prefix   {string}  Prefix for array-type parameters
+   *
+   * @returns  {string}
+   */
+  const interpolateParameters = (object, prefix = '') => {
+    let encodedString = '';
+    Object.keys(object).forEach(prop => {
+      if (typeof object[prop] !== 'object') {
+        if (encodedString.length > 0) {
+          encodedString += '&';
+        }
+        if (prefix === '') {
+          encodedString += `${encodeURIComponent(prop)}=${encodeURIComponent(object[prop])}`;
+        } else {
+          encodedString += `${encodeURIComponent(prefix)}[${encodeURIComponent(prop)}]=${encodeURIComponent(object[prop])}`;
+        }
+        return;
+      }
+
+      // Objects need special handling
+      encodedString += `${interpolateParameters(object[prop], prop)}`;
+    });
+    return encodedString;
+  };
+
+  /**
+   * Finds the first field matching a selector inside a form
+   *
+   * @param   {HTMLFormElement}  form           The FORM element
+   * @param   {String}           fieldSelector  The CSS selector to locate the field
+   *
+   * @returns {Element|null}  NULL when no element is found
+   */
+  const findField = (form, fieldSelector) => {
+    const elInputs = form.querySelectorAll(fieldSelector);
+    if (!elInputs.length) {
+      return null;
+    }
+    return elInputs[0];
+  };
+
+  /**
+   * Find a form field described by the CSS selector fieldSelector.
+   * The field must be inside a <form> element which is either the
+   * outerElement itself or enclosed by outerElement.
+   *
+   * @param   {Element}  outerElement   The element which is either our form or contains our form.
+   * @param   {String}   fieldSelector  The CSS selector to locate the field
+   *
+   * @returns {null|Element}  NULL when no element is found
+   */
+  const lookForField = (outerElement, fieldSelector) => {
+    let elInput = null;
+    if (!outerElement) {
+      return elInput;
+    }
+    const elElement = outerElement.parentElement;
+    if (elElement.nodeName === 'FORM') {
+      elInput = findField(elElement, fieldSelector);
+      return elInput;
+    }
+    const elForms = elElement.querySelectorAll('form');
+    if (elForms.length) {
+      for (let i = 0; i < elForms.length; i += 1) {
+        elInput = findField(elForms[i], fieldSelector);
+        if (elInput !== null) {
+          return elInput;
+        }
+      }
+    }
+    return null;
+  };
+
+  /**
+   * A simple error handler.
+   *
+   * @param   {String}  message
+   */
+  const handleLoginError = message => {
+    Joomla.renderMessages({
+      error: [message]
+    });
+  };
+
+  /**
+   * Handles the browser response for the user interaction with the authenticator. Redirects to an
+   * internal page which handles the login server-side.
+   *
+   * @param {  Object}  publicKey     Public key request options, returned from the server
+   */
+  const handleLoginChallenge = publicKey => {
+    const arrayToBase64String = a => btoa(String.fromCharCode(...a));
+    const base64url2base64 = input => {
+      let output = input.replace(/-/g, '+').replace(/_/g, '/');
+      const pad = output.length % 4;
+      if (pad) {
+        if (pad === 1) {
+          throw new Error('InvalidLengthError: Input base64url string is the wrong length to determine padding');
+        }
+        output += new Array(5 - pad).join('=');
+      }
+      return output;
+    };
+    if (!publicKey.challenge) {
+      handleLoginError(Joomla.Text._('PLG_SYSTEM_WEBAUTHN_ERR_INVALID_USERNAME'));
+      return;
+    }
+    publicKey.challenge = Uint8Array.from(window.atob(base64url2base64(publicKey.challenge)), c => c.charCodeAt(0));
+    if (publicKey.allowCredentials) {
+      publicKey.allowCredentials = publicKey.allowCredentials.map(data => {
+        data.id = Uint8Array.from(window.atob(base64url2base64(data.id)), c => c.charCodeAt(0));
+        return data;
+      });
+    }
+    navigator.credentials.get({
+      publicKey
+    }).then(data => {
+      const publicKeyCredential = {
+        id: data.id,
+        type: data.type,
+        rawId: arrayToBase64String(new Uint8Array(data.rawId)),
+        response: {
+          authenticatorData: arrayToBase64String(new Uint8Array(data.response.authenticatorData)),
+          clientDataJSON: arrayToBase64String(new Uint8Array(data.response.clientDataJSON)),
+          signature: arrayToBase64String(new Uint8Array(data.response.signature)),
+          userHandle: data.response.userHandle ? arrayToBase64String(new Uint8Array(data.response.userHandle)) : null
+        }
+      };
+
+      // Send the response to your server
+      const paths = Joomla.getOptions('system.paths');
+      window.location = `${paths ? `${paths.base}/index.php` : window.location.pathname}?${Joomla.getOptions('csrf.token')}=1&option=com_ajax&group=system&plugin=webauthn&` + `format=raw&akaction=login&encoding=redirect&data=${btoa(JSON.stringify(publicKeyCredential))}`;
+    }).catch(error => {
+      // Example: timeout, interaction refused...
+      handleLoginError(error);
+    });
+  };
+
+  /**
+   * Initialize the passwordless login, going through the server to get the registered certificates
+   * for the user.
+   *
+   * @param   {string}   formId       The login form's or login module's HTML ID
+   *
+   * @returns {boolean}  Always FALSE to prevent BUTTON elements from reloading the page.
+   */
+  // eslint-disable-next-line no-unused-vars
+  Joomla.plgSystemWebauthnLogin = formId => {
+    // Get the username
+    const elFormContainer = document.getElementById(formId);
+    const elUsername = lookForField(elFormContainer, 'input[name=username]');
+    const elReturn = lookForField(elFormContainer, 'input[name=return]');
+    if (elUsername === null) {
+      Joomla.renderMessages({
+        error: [Joomla.Text._('PLG_SYSTEM_WEBAUTHN_ERR_CANNOT_FIND_USERNAME')]
+      });
+      return false;
+    }
+    const username = elUsername.value;
+    const returnUrl = elReturn ? elReturn.value : null;
+
+    // No username? We cannot proceed. We need a username to find the acceptable public keys :(
+    if (username === '') {
+      Joomla.renderMessages({
+        error: [Joomla.Text._('PLG_SYSTEM_WEBAUTHN_ERR_EMPTY_USERNAME')]
+      });
+      return false;
+    }
+
+    // Get the Public Key Credential Request Options (challenge and acceptable public keys)
+    const postBackData = {
+      option: 'com_ajax',
+      group: 'system',
+      plugin: 'webauthn',
+      format: 'raw',
+      akaction: 'challenge',
+      encoding: 'raw',
+      username,
+      returnUrl
+    };
+    postBackData[Joomla.getOptions('csrf.token')] = 1;
+    const paths = Joomla.getOptions('system.paths');
+    Joomla.request({
+      url: `${paths ? `${paths.base}/index.php` : window.location.pathname}?${Joomla.getOptions('csrf.token')}=1`,
+      method: 'POST',
+      data: interpolateParameters(postBackData),
+      onSuccess(rawResponse) {
+        let jsonData = {};
+        try {
+          jsonData = JSON.parse(rawResponse);
+        } catch (e) {
+          /**
+           * In case of JSON decoding failure fall through; the error will be handled in the login
+           * challenge handler called below.
+           */
+        }
+        handleLoginChallenge(jsonData);
+      },
+      onError: xhr => {
+        handleLoginError(`${xhr.status} ${xhr.statusText}`);
+      }
+    });
+    return false;
+  };
+
+  // Initialization. Runs on DOM content loaded since this script is always loaded deferred.
+  document.querySelectorAll('.plg_system_webauthn_login_button').forEach(button => {
+    button.addEventListener('click', ({
+      currentTarget
+    }) => Joomla.plgSystemWebauthnLogin(currentTarget.getAttribute('data-webauthn-form')));
+  });
+})(Joomla, document);