No security updates for partner by default
You will get security updates for all your regular repositories, including main, restricted, universe and multiverse, but not for partner.
The top-level structure of the precise-security repository makes this quite clear:
The packages in partners are basically proprietary binaries wrapped in a .deb. Incremental "security" updates are not released for these, just regular updates (new versions), which may include security updates. To find out if an update addresses security issues, either look at the provider's page for the update or in the changelog at the launchpad "source" page. The latter is typically easier, e.g. for Adobe Reader (
acroread), go to:
Expanding the latest release for Precise 12.04 shows you the changelog (emphasis added):
New upstream release, addresses security issues:
Well, how do I quickly check for regular updates to partner, then?
The partners repository contains just fifteen packages, and I imagine even regular updates are infrequent (think Adobe Reader). Given the tiny size (5 kb) of the partner update file, I'd just add the actual repository (
deb http://archive.canonical.com/ubuntu precise partner) to any "quick check" sources.list file.
precise-security exists on the partner server, it is (as expected) empty.