Shipping Position Independent Executables and using read-only Global Offset Table was already possible for packages but needed package maintainers to opt-in for each package (see Hardening wiki) using the “pie” and “bindnow” Dpkg hardening flags.
Now we can change that. We can make those hardening flags the default for every package.
We already have the needed patches for GCC (#835148) and dpkg (#835146, #835149). We already have all packages rebuilt once to test which breaks (Thanks to Lucas Nussbaum!). The Release Team already asked porters if they feel their ports ready for enabling PIE and most ports tentatively opted-in (Thanks to Niels Thykier for pushing this!).
What is left is fixing the ~75 open bugs found during the test rebuilds and this is where You can help, too! Please check if your packages are affected or give a helping hand to other maintainers who need it. (See PIEByDefaultTransition wiki for hints on fixing the bugs.) Many thanks to those who already fixed their packages!
If we can get past those last bugs we can enable those badly needed security features and make Stretch the most secure release ever!