The security label configuration needs to block the objects with restricted value when sharing to ProjectLink

[tvaz]

Currently the objects with "Private" or "Most Confidential" security label value are allowed to share to project when doing "Add to Project". This would lead to sharing confidential data to outside world when external collaboration is enabled in ProjectLink. So we need a way to restrict the sharing of objects to ProjectLink for all the restricted security label values.

[craymond]

I would suggest that "non sharing" should be a configuration selection on a per label basis.  It won't be true in all business cases that "all" non null labels shouldn't be shared.

It might be interesting if there was a way to set up a project to not accept certain labels, that would allow for different project having different business rules.

[SteveShaw]

When an object is shared to a project its security label is still valid and will block access to such an object for any users in the project that are not cleared for such a security label value or applicable agreement.