Mihai Sucan [:msucan] Reporter
	Description • 11 years ago

Given compartments A, B and C, object O which lives in B, and a variable V in A that points to object O. B is nuked at some later point but V is still there, as a DeadObject. If you get V from C and you call Cu.isDeadWrapper(V) you get |false|. You only get |true| if you call Cu.isDeadWrapper(V) from A. We would need this to work from other compartments as well.

Bobby Holley said the following in bug 883649 comment #14:

> Once a wrapper is nuked, it ceases to become a wrapper at all. This means
> that passing the nuked wrapper across compartment boundaries will end up
> with a CCW to a DeadObjectProxy, rather than another DeadObjectProxy.
> 
> If it would be helpful, we could make Cu.IsDeadWrapper unwrap CCWs, so if
> would give the right answer here. If it would, please file a bug and CC me.

... in reply to bug 883649 comment 13.

	Gabor Krizsanits (INACTIVE)
	Comment 2 • 11 years ago

Comment on attachment 766106 [details] [diff] [review]
Unwrap CCWs in Cu.isDeadWrapper. v1

Review of attachment 766106 [details] [diff] [review]:
-----------------------------------------------------------------

I don't really see why do you not just use the unchecked unwrap here, but since it's a Cu method, probably does not matter.

	Bobby Holley (:bholley)
	Comment 3 • 11 years ago

(In reply to Gabor Krizsanits [:krizsa :gabor] (sick) from comment #2)
> Comment on attachment 766106 [details] [diff] [review]
> Unwrap CCWs in Cu.isDeadWrapper. v1
> 
> Review of attachment 766106 [details] [diff] [review]:
> -----------------------------------------------------------------
> 
> I don't really see why do you not just use the unchecked unwrap here, but
> since it's a Cu method, probably does not matter.

We should always use CheckedUnwrap unless we have an explicit need for UncheckedUnwrap, since the latter is a a potential security risk. I'd like to minimize the MXR results for UncheckedUnwrap.

	Bobby Holley (:bholley)
	Comment 4 • 11 years ago

https://hg.mozilla.org/integration/mozilla-inbound/rev/ab82dbf50dd2

	Phil Ringnalda (:philor)
	Comment 5 • 11 years ago

https://hg.mozilla.org/mozilla-central/rev/ab82dbf50dd2