On Fri, Aug 21, 2020 at 8:15 AM Stephen Smalley <stephen.smalley.work@xxxxxxxxx> wrote: > > On Thu, Aug 20, 2020 at 10:22 PM Paul Moore <paul@xxxxxxxxxxxxxx> wrote: > > > > On Tue, Aug 18, 2020 at 8:14 AM Stephen Smalley > > <stephen.smalley.work@xxxxxxxxx> wrote: > > > On Tue, Aug 18, 2020 at 4:11 AM peter enderborg <peter.enderborg@xxxxxxxx> wrote: > > > > ... > > > > > > Is there any other things we need to fix? A part 1&2 now OK? > > > > > > They looked ok to me, but Paul should review them. > > > > Patches 1 and 2 look fine to me with the small nits that Stephen > > pointed out corrected. I'm glad to see the information in string form > > now, I think that will be a big help for people making use of this. > > > > Unfortunately, I'm a little concerned about patch 3 for the reason > > Stephen already mentioned. While changes to the class mapping are > > infrequent, they do happen, and I'm not very excited about adding it > > to the userspace kAPI via a header. Considering that the tracing > > tools are going to be running on the same system that is being > > inspected, perhaps the tracing tools could inspect > > /sys/fs/selinux/class at runtime to query the permission mappings? > > Stephen, is there a libselinux API which does this already? > > There is a libselinux API but both it and the /sys/fs/selinux/class > tree is exposing the policy values for classes/permissions, not the > kernel-private indices. The dynamic class/perm mapping support > introduced a layer of indirection between them. The tracepoint is in > the avc and therefore dealing with the kernel-private values, not the > policy values. The mapping occurs on entry/exit of the security > server functions. So there is no way for userspace to read the kernel > class/perm values. We'd just need to keep them in sync manually. And > one is allowed to insert new classes or permissions before existing > ones, thereby changing the values of existing ones, or even to remove > them. Ah, okay, thanks. Can you tell I've never really had to look very closely at that code ;) -- paul moore www.paul-moore.com
