1 files changed, 341 insertions, 0 deletions
diff --git a/dom/media/PeerConnectionIdp.jsm b/dom/media/PeerConnectionIdp.jsm
new file mode 100644
index 000000000..d1578d1b7
--- /dev/null
+++ b/dom/media/PeerConnectionIdp.jsm
@@ -0,0 +1,341 @@
+/* jshint moz:true, browser:true */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+this.EXPORTED_SYMBOLS = ['PeerConnectionIdp'];
+
+const {classes: Cc, interfaces: Ci, utils: Cu} = Components;
+
+Cu.import('resource://gre/modules/Services.jsm');
+Cu.import('resource://gre/modules/XPCOMUtils.jsm');
+XPCOMUtils.defineLazyModuleGetter(this, 'IdpSandbox',
+  'resource://gre/modules/media/IdpSandbox.jsm');
+
+/**
+ * Creates an IdP helper.
+ *
+ * @param win (object) the window we are working for
+ * @param timeout (int) the timeout in milliseconds
+ */
+function PeerConnectionIdp(win, timeout) {
+  this._win = win;
+  this._timeout = timeout || 5000;
+
+  this.provider = null;
+  this._resetAssertion();
+}
+
+(function() {
+  PeerConnectionIdp._mLinePattern = new RegExp('^m=', 'm');
+  // attributes are funny, the 'a' is case sensitive, the name isn't
+  let pattern = '^a=[iI][dD][eE][nN][tT][iI][tT][yY]:(\\S+)';
+  PeerConnectionIdp._identityPattern = new RegExp(pattern, 'm');
+  pattern = '^a=[fF][iI][nN][gG][eE][rR][pP][rR][iI][nN][tT]:(\\S+) (\\S+)';
+  PeerConnectionIdp._fingerprintPattern = new RegExp(pattern, 'm');
+})();
+
+PeerConnectionIdp.prototype = {
+  get enabled() {
+    return !!this._idp;
+  },
+
+  _resetAssertion: function() {
+    this.assertion = null;
+    this.idpLoginUrl = null;
+  },
+
+  setIdentityProvider: function(provider, protocol, username) {
+    this._resetAssertion();
+    this.provider = provider;
+    this.protocol = protocol || 'default';
+    this.username = username;
+    if (this._idp) {
+      if (this._idp.isSame(provider, protocol)) {
+        return; // noop
+      }
+      this._idp.stop();
+    }
+    this._idp = new IdpSandbox(provider, protocol, this._win);
+  },
+
+  // start the IdP and do some error fixup
+  start: function() {
+    return this._idp.start()
+      .catch(e => {
+        throw new this._win.DOMException(e.message, 'IdpError');
+      });
+  },
+
+  close: function() {
+    this._resetAssertion();
+    this.provider = null;
+    this.protocol = null;
+    if (this._idp) {
+      this._idp.stop();
+      this._idp = null;
+    }
+  },
+
+  _getFingerprintsFromSdp: function(sdp) {
+    let fingerprints = {};
+    let m = sdp.match(PeerConnectionIdp._fingerprintPattern);
+    while (m) {
+      fingerprints[m[0]] = { algorithm: m[1], digest: m[2] };
+      sdp = sdp.substring(m.index + m[0].length);
+      m = sdp.match(PeerConnectionIdp._fingerprintPattern);
+    }
+
+    return Object.keys(fingerprints).map(k => fingerprints[k]);
+  },
+
+  _isValidAssertion: function(assertion) {
+    return assertion && assertion.idp &&
+      typeof assertion.idp.domain === 'string' &&
+      (!assertion.idp.protocol ||
+       typeof assertion.idp.protocol === 'string') &&
+      typeof assertion.assertion === 'string';
+  },
+
+  _getIdentityFromSdp: function(sdp) {
+    // a=identity is session level
+    let idMatch;
+    let mLineMatch = sdp.match(PeerConnectionIdp._mLinePattern);
+    if (mLineMatch) {
+      let sessionLevel = sdp.substring(0, mLineMatch.index);
+      idMatch = sessionLevel.match(PeerConnectionIdp._identityPattern);
+    }
+    if (!idMatch) {
+      return; // undefined === no identity
+    }
+
+    let assertion;
+    try {
+      assertion = JSON.parse(atob(idMatch[1]));
+    } catch (e) {
+      throw new this._win.DOMException('invalid identity assertion: ' + e,
+                                       'InvalidSessionDescriptionError');
+    }
+    if (!this._isValidAssertion(assertion)) {
+      throw new this._win.DOMException('assertion missing idp/idp.domain/assertion',
+                                       'InvalidSessionDescriptionError');
+    }
+    return assertion;
+  },
+
+  /**
+   * Verifies the a=identity line the given SDP contains, if any.
+   * If the verification succeeds callback is called with the message from the
+   * IdP proxy as parameter, else (verification failed OR no a=identity line in
+   * SDP at all) null is passed to callback.
+   *
+   * Note that this only verifies that the SDP is coherent.  We still rely on
+   * the fact that the RTCPeerConnection won't connect to a peer if the
+   * fingerprint of the certificate they offer doesn't appear in the SDP.
+   */
+  verifyIdentityFromSDP: function(sdp, origin) {
+    let identity = this._getIdentityFromSdp(sdp);
+    let fingerprints = this._getFingerprintsFromSdp(sdp);
+    if (!identity || fingerprints.length <= 0) {
+      return this._win.Promise.resolve(); // undefined result = no identity
+    }
+
+    this.setIdentityProvider(identity.idp.domain, identity.idp.protocol);
+    return this._verifyIdentity(identity.assertion, fingerprints, origin);
+  },
+
+  /**
+   * Checks that the name in the identity provided by the IdP is OK.
+   *
+   * @param name (string) the name to validate
+   * @throws if the name isn't valid
+   */
+  _validateName: function(name) {
+    let error = msg => {
+        throw new this._win.DOMException('assertion name error: ' + msg,
+                                         'IdpError');
+    };
+
+    if (typeof name !== 'string') {
+      error('name not a string');
+    }
+    let atIdx = name.indexOf('@');
+    if (atIdx <= 0) {
+      error('missing authority in name from IdP');
+    }
+
+    // no third party assertions... for now
+    let tail = name.substring(atIdx + 1);
+
+    // strip the port number, if present
+    let provider = this.provider;
+    let providerPortIdx = provider.indexOf(':');
+    if (providerPortIdx > 0) {
+      provider = provider.substring(0, providerPortIdx);
+    }
+    let idnService = Components.classes['@mozilla.org/network/idn-service;1']
+        .getService(Components.interfaces.nsIIDNService);
+    if (idnService.convertUTF8toACE(tail) !==
+        idnService.convertUTF8toACE(provider)) {
+      error('name "' + name +
+            '" doesn\'t match IdP: "' + this.provider + '"');
+    }
+  },
+
+  /**
+   * Check the validation response.  We are very defensive here when handling
+   * the message from the IdP proxy.  That way, broken IdPs aren't likely to
+   * cause catastrophic damage.
+   */
+  _checkValidation: function(validation, sdpFingerprints) {
+    let error = msg => {
+      throw new this._win.DOMException('IdP validation error: ' + msg,
+                                       'IdpError');
+    };
+
+    if (!this.provider) {
+      error('IdP closed');
+    }
+
+    if (typeof validation !== 'object' ||
+        typeof validation.contents !== 'string' ||
+        typeof validation.identity !== 'string') {
+      error('no payload in validation response');
+    }
+
+    let fingerprints;
+    try {
+      fingerprints = JSON.parse(validation.contents).fingerprint;
+    } catch (e) {
+      error('invalid JSON');
+    }
+
+    let isFingerprint = f =>
+        (typeof f.digest === 'string') &&
+        (typeof f.algorithm === 'string');
+    if (!Array.isArray(fingerprints) || !fingerprints.every(isFingerprint)) {
+      error('fingerprints must be an array of objects' +
+            ' with digest and algorithm attributes');
+    }
+
+    // everything in `innerSet` is found in `outerSet`
+    let isSubsetOf = (outerSet, innerSet, comparator) => {
+      return innerSet.every(i => {
+        return outerSet.some(o => comparator(i, o));
+      });
+    };
+    let compareFingerprints = (a, b) => {
+      return (a.digest === b.digest) && (a.algorithm === b.algorithm);
+    };
+    if (!isSubsetOf(fingerprints, sdpFingerprints, compareFingerprints)) {
+      error('the fingerprints must be covered by the assertion');
+    }
+    this._validateName(validation.identity);
+    return validation;
+  },
+
+  /**
+   * Asks the IdP proxy to verify an identity assertion.
+   */
+  _verifyIdentity: function(assertion, fingerprints, origin) {
+    let p = this.start()
+        .then(idp => this._wrapCrossCompartmentPromise(
+          idp.validateAssertion(assertion, origin)))
+        .then(validation => this._checkValidation(validation, fingerprints));
+
+    return this._applyTimeout(p);
+  },
+
+  /**
+   * Enriches the given SDP with an `a=identity` line.  getIdentityAssertion()
+   * must have already run successfully, otherwise this does nothing to the sdp.
+   */
+  addIdentityAttribute: function(sdp) {
+    if (!this.assertion) {
+      return sdp;
+    }
+
+    // yes, we assume that this matches; if it doesn't something is *wrong*
+    let match = sdp.match(PeerConnectionIdp._mLinePattern);
+    return sdp.substring(0, match.index) +
+      'a=identity:' + this.assertion + '\r\n' +
+      sdp.substring(match.index);
+  },
+
+  /**
+   * Asks the IdP proxy for an identity assertion.  Don't call this unless you
+   * have checked .enabled, or you really like exceptions.  Also, don't call
+   * this when another call is still running, because it's not certain which
+   * call will finish first and the final state will be similarly uncertain.
+   */
+  getIdentityAssertion: function(fingerprint, origin) {
+    if (!this.enabled) {
+      throw new this._win.DOMException(
+        'no IdP set, call setIdentityProvider() to set one', 'InvalidStateError');
+    }
+
+    let [algorithm, digest] = fingerprint.split(' ', 2);
+    let content = {
+      fingerprint: [{
+        algorithm: algorithm,
+        digest: digest
+      }]
+    };
+
+    this._resetAssertion();
+    let p = this.start()
+        .then(idp => this._wrapCrossCompartmentPromise(
+          idp.generateAssertion(JSON.stringify(content),
+                                origin, this.username)))
+        .then(assertion => {
+          if (!this._isValidAssertion(assertion)) {
+            throw new this._win.DOMException('IdP generated invalid assertion',
+                                             'IdpError');
+          }
+          // save the base64+JSON assertion, since that is all that is used
+          this.assertion = btoa(JSON.stringify(assertion));
+          return this.assertion;
+        });
+
+    return this._applyTimeout(p);
+  },
+
+  /**
+   * Promises generated by the sandbox need to be very carefully treated so that
+   * they can chain into promises in the `this._win` compartment.  Results need
+   * to be cloned across; errors need to be converted.
+   */
+  _wrapCrossCompartmentPromise: function(sandboxPromise) {
+    return new this._win.Promise((resolve, reject) => {
+      sandboxPromise.then(
+        result => resolve(Cu.cloneInto(result, this._win)),
+        e => {
+          let message = '' + (e.message || JSON.stringify(e) || 'IdP error');
+          if (e.name === 'IdpLoginError') {
+            if (typeof e.loginUrl === 'string') {
+              this.idpLoginUrl = e.loginUrl;
+            }
+            reject(new this._win.DOMException(message, 'IdpLoginError'));
+          } else {
+            reject(new this._win.DOMException(message, 'IdpError'));
+          }
+        });
+    });
+  },
+
+  /**
+   * Wraps a promise, adding a timeout guard on it so that it can't take longer
+   * than the specified time.  Returns a promise that rejects if the timeout
+   * elapses before `p` resolves.
+   */
+  _applyTimeout: function(p) {
+    let timeout = new this._win.Promise(
+      r => this._win.setTimeout(r, this._timeout))
+        .then(() => {
+          throw new this._win.DOMException('IdP timed out', 'IdpError');
+        });
+    return this._win.Promise.race([ timeout, p ]);
+  }
+};
+
+this.PeerConnectionIdp = PeerConnectionIdp;