Script integrity check fails for extension iframes script tags

jeurissen

Given a third party web page with an iframe set to an extension html file which is specified in web_accessible_resources. A script file inside this iframe fails to load due to an integrity attribute check failure.

For the integrity check to succeed.

1.4.1

jeurissen

This breaks extensions like "G App Launcher" (https://addons.mozilla.org/en-US/firefox/addon/google-shortcuts-all-google-se/) with errors like:

Cannot load script moz-extension://5C46D283-ABDE-4dce-B83C-08881401921C/scripts/embed.js. Failed integrity metadata check. Content length: 2451, Expected content length: 2451, Expected metadata: sha384-EIaw0Qw/eLc9kSxntAt36P7HKboDD7HgVME+da8E6QXiRibfyQIhmHYvdnzIJJ/3

RoxyRoxyRoxy

CC @nrudnyk