Messages in this thread | | | Date | Mon, 02 Jul 2007 15:03:02 -0400 | From | Rik van Riel <> | Subject | Re: [patch 0/4] MAP_NOZERO v2 - VM_NOZERO/MAP_NOZERO early summer madness |
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Andy Isaacson wrote: > On Sat, Jun 30, 2007 at 08:21:52PM -0400, Kyle Moffett wrote: >> That's why you'd need to call an LSM hook to get a unique identifier, >> as the LSM would actually need to allocate identifiers for >> equivalence classes. Secondly, processes may change labels as they >> run, so you couldn't just call it once and cache the result, you >> would need to call it for every freed page (or every re-use of a page). > > Davide's patch adds a owner_uid field to mm_struct. Assuming that turns > into a "mm security equivalence class identifier", the LSM can simply > update it when a label-change-event occurs. No need to call out to > (potentially heavyweight!) LSM code in page allocation critical paths. > > I'm a bit concerned that tracking the equivalence classes will get > expensive. I think you can end up with quadratic explosion in the worst > case (every user using every permutation of LSM bits).
That should not happen. The default SELinux configuration in Fedora (and Debian?) runs a few daemons in their own restricted modes and has most of the system running in unconfined_t, including the majority of user programs.
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