[jraph]

I don't think that's true. "If you redistribute we stop collaboration" is not a restriction on the source code the customer has access to.

I think this clause doesn't mean what you mean. This clause means that the GRSecurity project can't license their modifications under a more restrictive license than the GPL. Which the GRSecurity project respects, customers do have access to the modifications under the GPL license.

[pabs3]

One of those customers also redistributed GRSec modifications:

https://github.com/jameshilliard/linux-grsec