> The problem is, IIRC, that GPLv2 does not allow creating a combined work where part of it is covered by license that has stricter requirements than GPL

That is part of the virality: the combined work is under the terms of the GPL and therefore cannot have additional restrictions placed on it. If the GPL wasn't viral then the GPL code and CDDL code would both be under their respective licenses and leave each other alone. The GPL decided to apply itself to the combined work which causes the problems.