android_system_sepolicy/public/otapreopt_chroot.te
Benjamin Gordon 9b2e0cbeea sepolicy: Add rules for non-init namespaces
In kernel 4.7, the capability and capability2 classes were split apart
from cap_userns and cap2_userns (see kernel commit
8e4ff6f228e4722cac74db716e308d1da33d744f). Since then, Android cannot be
run in a container with SELinux in enforcing mode.

This change applies the existing capability rules to user namespaces as
well as the root namespace so that Android running in a container
behaves the same on pre- and post-4.7 kernels.

This is essentially:
  1. New global_capability_class_set and global_capability2_class_set
     that match capability+cap_userns and capability2+cap2_userns,
     respectively.
  2. s/self:capability/self:global_capability_class_set/g
  3. s/self:capability2/self:global_capability2_class_set/g
  4. Add cap_userns and cap2_userns to the existing capability_class_set
     so that it covers all capabilities.  This set was used by several
     neverallow and dontaudit rules, and I confirmed that the new
     classes are still appropriate.

Test: diff new policy against old and confirm that all new rules add
      only cap_userns or cap2_userns;
      Boot ARC++ on a device with the 4.12 kernel.
Bug: crbug.com/754831

Change-Id: I4007eb3a2ecd01b062c4c78d9afee71c530df95f
2017-11-21 08:34:32 -07:00

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# otapreopt_chroot executable
type otapreopt_chroot, domain;
type otapreopt_chroot_exec, exec_type, file_type;
# Chroot preparation and execution.
# We need to create an unshared mount namespace, and then mount /data.
allow otapreopt_chroot postinstall_file:dir { search mounton };
allow otapreopt_chroot self:global_capability_class_set { sys_admin sys_chroot };
# This is required to mount /vendor.
allow otapreopt_chroot block_device:dir search;
allow otapreopt_chroot labeledfs:filesystem mount;
# Mounting /vendor can have this side-effect. Ignore denial.
dontaudit otapreopt_chroot kernel:process setsched;
# Allow otapreopt to use file descriptors from update-engine. It will
# close them immediately.
allow otapreopt_chroot postinstall:fd use;
allow otapreopt_chroot update_engine:fd use;
allow otapreopt_chroot update_engine:fifo_file write;