The hotfix extension does two things:
1) Install a new certificate for "CN=signingca1.addons.mozilla.org/[email protected]", effectively replacing the old certificate that expired. This should work.
2) Then it tries to import the internal "resource://gre/modules/addons/XPIDatabase.jsm" module and calls XPIDatabase.verifySignatures().
This does not work on ESR, as "XPIDatabase.jsm" is a new-ish thing that isn't present in ESR yet. In ESR the function is still in "resource://gre/modules/addons/XPIProvider.jsm" (XPIProvider.verifySignatures()). Thankfully, the non-existing module is imported using ChromeUtils.defineModuleGetter, which only lazily loads the module on first of the imported property, so after the certificate-adding code has run.
https://storage.googleapis.com/moz-fx-normandy-prod-addons/e...
Can mozilla please verify, confirm authenticity, and list this instruction on their issue page?
I encourage you to go through the whole Normandy process yourself in a test environment, and even better (if possible), check out the code to see whether it looks legit or benign.
I'm happy, because I went through and checked it out myself without needing to enable Normandy on my actual Firefox, but ultimately, it will be great when Moz can get instructions for manually applying the fix out.
This fixed it for me. Thanks. W10/FF 66.0.3
hotfix-update-xpi-signing-intermediate-bug-1548973: https://storage.googleapis.com/moz-fx-normandy-prod-addons/e...
From the looks, it installs the above plugin, and changes `app.update.lastUpdateTime.xpi-signature-verification` to `1556945257`
I can't get it to work in ESR 60 though. Getting file not found on "resource://gre/modules/addons/XPIDatabase.jsm"
edit: The linked XPI definitely seems to add the new certificate, whatever mechanism used to reverify the signatures just doesn't seem to work in 60.
edit2: Restarting Firefox appears to have forced the reverify... Possibly a flag that I twiddled with though, hard to be sure. Either way, the above should help people get everything running again without having to enable studies/normandy.