On Sun, Nov 22, 2020 at 3:14 PM Paul Moore <paul@xxxxxxxxxxxxxx> wrote: > > On Wed, Nov 18, 2020 at 5:39 PM Lokesh Gidra <lokeshgidra@xxxxxxxxxx> wrote: > > I have created a cuttlefish build and have tested with the attached > > userfaultfd program: > > Thanks, that's a good place to start, a few comments: > > - While we support Android as a distribution, it isn't a platform that > we common use for development and testing. At the moment, Fedora is > probably your best choice for that. > I tried setting up a debian/ubuntu system for testing using the instructions on the selinux-testsuite page, but the system kept freezing after 'setenforce 1'. I'll try with fedora now. > - Your test program should be written in vanilla C for the > selinux-testsuite. Looking at the userfaultfdSimple.cc code that > should be a trivial conversion. > > - I think you have a good start on a test for the selinux-testsuite, > please take a look at the test suite and submit a patch against that > repo. Ondrej (CC'd) currently maintains the test suite and he may > have some additional thoughts. > > * https://github.com/SELinuxProject/selinux-testsuite Thanks a lot for the inputs. I'll start working on this. > > > 1) Without these kernel patches the program executes without any restrictions > > > > vsoc_x86_64:/ $ ./system/bin/userfaultfdSimple > > api: 170 > > features: 511 > > ioctls: 9223372036854775811 > > > > read: Try again > > > > > > 2) With these patches applied but without any policy the 'permission > > denied' is thrown > > > > vsoc_x86_64:/ $ ./system/bin/userfaultfdSimple > > syscall(userfaultfd): Permission denied > > > > with the following logcat message: > > 11-18 14:21:44.041 3130 3130 W userfaultfdSimp: type=1400 > > audit(0.0:107): avc: denied { create } for dev="anon_inodefs" > > ino=45031 scontext=u:r:shell:s0 tcontext=u:object_r:shell:s0 > > tclass=anon_inode permissive=0 > > > > > > 3) With the attached .te policy file in place the following output is > > observed, confirming that the patch is working as intended. > > vsoc_x86_64:/ $ ./vendor/bin/userfaultfdSimple > > UFFDIO_API: Permission denied > > > > with the following logcat message: > > 11-18 14:33:29.142 2028 2028 W userfaultfdSimp: type=1400 > > audit(0.0:104): avc: denied { ioctl } for > > path="anon_inode:[userfaultfd]" dev="anon_inodefs" ino=41169 > > ioctlcmd=0xaa3f scontext=u:r:userfaultfdSimple:s0 > > tcontext=u:object_r:uffd_t:s0 tclass=anon_inode permissive=0 > > -- > paul moore > www.paul-moore.com
