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/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
/* 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
// Preference containing the list (space separated) of origins that are
// allowed to send non-string values through a WebChannel, mainly for
const URL_WHITELIST_PREF = "webchannel.allowObject.urlWhitelist";
let _cachedWhitelist = null;
const CACHED_PREFS = {};
XPCOMUtils.defineLazyPreferenceGetter(
CACHED_PREFS,
"URL_WHITELIST",
URL_WHITELIST_PREF,
"",
// Null this out so we update it.
() => (_cachedWhitelist = null)
);
export class WebChannelChild extends JSWindowActorChild {
handleEvent(event) {
if (event.type === "WebChannelMessageToChrome") {
return this._onMessageToChrome(event);
}
return undefined;
}
receiveMessage(msg) {
if (msg.name === "WebChannelMessageToContent") {
return this._onMessageToContent(msg);
}
return undefined;
}
_getWhitelistedPrincipals() {
if (!_cachedWhitelist) {
let urls = CACHED_PREFS.URL_WHITELIST.split(/\s+/);
_cachedWhitelist = urls.map(origin =>
Services.scriptSecurityManager.createContentPrincipalFromOrigin(origin)
);
}
return _cachedWhitelist;
}
_onMessageToChrome(e) {
// If target is window then we want the document principal, otherwise fallback to target itself.
let principal = e.target.nodePrincipal
? e.target.nodePrincipal
: e.target.document.nodePrincipal;
if (e.detail) {
if (typeof e.detail != "string") {
// Check if the principal is one of the ones that's allowed to send
// non-string values for e.detail. They're whitelisted by site origin,
// so we compare on originNoSuffix in order to avoid other origin attributes
// that are not relevant here, such as containers or private browsing.
let objectsAllowed = this._getWhitelistedPrincipals().some(
whitelisted => principal.originNoSuffix == whitelisted.originNoSuffix
);
if (!objectsAllowed) {
console.error(
"WebChannelMessageToChrome sent with an object from a non-whitelisted principal"
);
return;
}
}
let eventTarget =
e.target instanceof Ci.nsIDOMWindow
? null
: ContentDOMReference.get(e.target);
this.sendAsyncMessage("WebChannelMessageToChrome", {
contentData: e.detail,
eventTarget,
principal,
});
} else {
console.error("WebChannel message failed. No message detail.");
}
}
_onMessageToContent(msg) {
if (msg.data && this.contentWindow) {
// msg.objects.eventTarget will be defined if sending a response to
// a WebChannelMessageToChrome event. An unsolicited send
// may not have an eventTarget defined, in this case send to the
// main content window.
let { eventTarget, principal } = msg.data;
if (!eventTarget) {
eventTarget = this.contentWindow;
} else {
eventTarget = ContentDOMReference.resolve(eventTarget);
}
if (!eventTarget) {
console.error("WebChannel message failed. No target.");
return;
}
// Use nodePrincipal if available, otherwise fallback to document principal.
let targetPrincipal =
eventTarget instanceof Ci.nsIDOMWindow
? eventTarget.document.nodePrincipal
: eventTarget.nodePrincipal;
if (principal.subsumes(targetPrincipal)) {
let targetWindow = this.contentWindow;
eventTarget.dispatchEvent(
new targetWindow.CustomEvent("WebChannelMessageToContent", {
detail: Cu.cloneInto(
{
id: msg.data.id,
message: msg.data.message,
},
targetWindow
),
})
);
} else {
console.error("WebChannel message failed. Principal mismatch.");
}
} else {
console.error("WebChannel message failed. No message data.");
}
}
}