Introduce a `postinstall_apex_mnt_dir` label for `/postinstall/apex`.
Directory `/postinstall/apex` is used as a mount point for a tmpfs
filesystem during A/B OTA updates. APEX packages from the new system
partition are mounted ("activated") in subdirectories of
`/postinstall/apex`, so that they are available when `otapreopt` is
running.
Directory `/postinstall/apex` used to be of type `tmpfs` for SELinux
purposes. The new `postinstall_apex_mnt_dir` label is more
restrictive, and tightens permissions granted to `otapreopt_chroot`,
`otapreopt` (running as `postinstall_dexopt`), and `dex2oat`,
regarding the apexd logic recently added to `otapreopt_chroot`.
Test: A/B OTA update test (asit/dexoptota/self_full).
Bug: 113373927
Bug: 120796514
Change-Id: I03f0b0433d9c066a0c607f864d60ca62fc68c990
diff --git a/private/file_contexts b/private/file_contexts
index af9572d..89c11bd 100644
--- a/private/file_contexts
+++ b/private/file_contexts
@@ -28,6 +28,7 @@
/config u:object_r:rootfs:s0
/mnt u:object_r:tmpfs:s0
/postinstall u:object_r:postinstall_mnt_dir:s0
+/postinstall/apex u:object_r:postinstall_apex_mnt_dir:s0
/proc u:object_r:rootfs:s0
/sys u:object_r:sysfs:s0
/apex u:object_r:apex_mnt_dir:s0