Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

Function.prototype.constructor is tamed in the host #52

Open
evanw opened this issue Sep 16, 2019 · 7 comments · May be fixed by #305
Open

Function.prototype.constructor is tamed in the host #52

evanw opened this issue Sep 16, 2019 · 7 comments · May be fixed by #305

Comments

@evanw
Copy link

evanw commented Sep 16, 2019

We recently ran into a problem with the Realm shim. We're injecting the shim into our page via <script src="..."> and then using the Realm object. However, that causes Function to be tamed in the host page, which we weren't expecting to happen.

Recently we upgraded selenium-webdriver, one of our 3rd-party dependencies, that apparently now calls Function("...") to eval something. When the Realm shim is loaded, that no longer works. We end up getting TypeError: Not available when we call their driver.executeScript API call.

Is there a reason to tame Function in the host environment? We think we can work around it on our end by loading the Realm shim into a same-origin iframe instead, but I wanted to file this issue with you in case this behavior was unintended. I imagine this behavior will also trip up others trying to use the shim in the future.
@Jack-Works
Copy link
Contributor

Also have this problem when developing WebExtension-shim

@erights
Copy link
Member

erights commented Sep 18, 2019

I am not sure I understand which realm's Function constructor you mean. When you create a new root realm, the Function constructor of that realm is indeed tamed. By "host page", do you mean the realm from which you asked to make a new root realm, as opposed to the root realm created by such a call? If so, then this indeed surprises me and is likely a bug. Could you post a small piece of code that demonstrates the problem? Thanks.

@Jack-Works
Copy link
Contributor

When you creating a new realm, the outside world (out of the sandbox)'s Function is polluted. And code relay on that can not work properly

@erights
Copy link
Member

erights commented Sep 18, 2019

Ok, that is definitely a bug. Will investigate. Thanks all!!!

@Jack-Works
Copy link
Contributor

A fix is available at 969f1fe

@Jack-Works Jack-Works mentioned this issue Sep 28, 2019
Closed
@ExE-Boss
Copy link
Contributor

ExE-Boss commented Sep 30, 2020 •
edited
Loading

The correct fix is to delete this line in createCurrentUnsafeRec():

realms-shim/src/unsafeRec.js

Line 130 in 067bdd9

repairFunctions();

Turns out, that breaks makeCompartment().

@ExE-Boss ExE-Boss linked a pull request Sep 30, 2020 that will close this issue
Draft
@erights
Copy link
Member

erights commented Sep 30, 2020

Before shutting down or transferring the realms shim, in addition to applying relevant improvements to the compartments shim (see endojs/endo#481) we should also migrate relevant outstanding open PRs and issues, such as this one.

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Assignees
No one assigned
Labels
None yet
Projects
None yet
Milestone
No milestone
4 participants
@erights @evanw @ExE-Boss @Jack-Works