gecko/dom/media/PeerConnectionIdp.jsm

342 lines
11 KiB
JavaScript

/* 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 "' + identity.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;