Move creation of /data/user/0 and /data/media/obb to vold

To prevent bugs, directory creation and encryption should happen
together.  /data/user/0 (and its "alias" /data/data) is a per-user
encrypted directory; such directories can only be encrypted by vold.
Therefore, move its creation to vold as well.

Besides closing the uncomfortably-large gap between the creation and
encryption of /data/user/0, this allows removing init's write access to
/data/user and similar directories (SELinux type system_userdir_file) to
prevent any such issues from being reintroduced in the future.

To also allow removing init's write access to /data/media (SELinux type
media_userdir_file), which also contains per-user encrypted directories,
also move the creation and encryption of /data/media/obb to vold.

Bug: 156305599
BYPASS_INCLUSIVE_LANGUAGE_REASON=Linux API ("slave" mount flag)
Change-Id: I7245251eeb56b345b6c7711482c0aa5848648edb
diff --git a/init/util.cpp b/init/util.cpp
index d1e518b..af6cf50 100644
--- a/init/util.cpp
+++ b/init/util.cpp
@@ -465,12 +465,6 @@
         return FscryptAction::kNone;
     }
 
-    // Special-case /data/media/obb per b/64566063
-    if (dir == "/data/media/obb") {
-        // Try to set policy on this directory, but if it is non-empty this may fail.
-        return FscryptAction::kAttempt;
-    }
-
     // Only set policy on first level /data directories
     // To make this less restrictive, consider using a policy file.
     // However this is overkill for as long as the policy is simply
diff --git a/rootdir/init.rc b/rootdir/init.rc
index 69e06d0..a255d17 100644
--- a/rootdir/init.rc
+++ b/rootdir/init.rc
@@ -840,7 +840,6 @@
     # Do not place files or directories in /data/local/tmp
     mkdir /data/local/tmp 0771 shell shell
     mkdir /data/local/traces 0777 shell shell
-    mkdir /data/data 0771 system system encryption=None
     mkdir /data/app-private 0771 system system encryption=Require
     mkdir /data/app-ephemeral 0771 system system encryption=Require
     mkdir /data/app-asec 0700 root root encryption=Require
@@ -915,13 +914,6 @@
     mkdir /data/user 0711 system system encryption=None
     mkdir /data/user_de 0711 system system encryption=None
 
-    # Unlink /data/user/0 if we previously symlink it to /data/data
-    rm /data/user/0
-
-    # Bind mount /data/user/0 to /data/data
-    mkdir /data/user/0 0700 system system encryption=None
-    mount none /data/data /data/user/0 bind rec
-
     # A tmpfs directory, which will contain all apps CE DE data directory that
     # bind mount from the original source.
     mount tmpfs tmpfs /data_mirror nodev noexec nosuid mode=0700,uid=0,gid=1000
@@ -933,8 +925,10 @@
     mkdir /data_mirror/data_ce/null 0700 root root
     mkdir /data_mirror/data_de/null 0700 root root
 
-    # Bind mount CE and DE data directory to mirror's default volume directory
-    mount none /data/user /data_mirror/data_ce/null bind rec
+    # Bind mount CE and DE data directory to mirror's default volume directory.
+    # The 'slave' option (MS_SLAVE) is needed to cause the later bind mount of
+    # /data/data onto /data/user/0 to propagate to /data_mirror/data_ce/null/0.
+    mount none /data/user /data_mirror/data_ce/null bind rec slave
     mount none /data/user_de /data_mirror/data_de/null bind rec
 
     # Create mirror directory for jit profiles
@@ -967,10 +961,8 @@
     wait_for_prop apexd.status activated
     perform_apex_config
 
-    # Special-case /data/media/obb per b/64566063
     mkdir /data/media 0770 media_rw media_rw encryption=None
     exec - media_rw media_rw -- /system/bin/chattr +F /data/media
-    mkdir /data/media/obb 0770 media_rw media_rw encryption=Attempt
 
     # Create directories for boot animation.
     mkdir /data/bootanim 0755 system system encryption=None