Securely encrypt the master key

Remove unencrypted link since it is easier to manage directly
Move creation of key to vold
Start vold early so this is possible in a timely fashion

This is one of four changes to enable this functionality:
  https://android-review.googlesource.com/#/c/144586/
  https://android-review.googlesource.com/#/c/144663/
  https://android-review.googlesource.com/#/c/144672/
  https://android-review.googlesource.com/#/c/144673/

Bug: 18151196
Change-Id: Idb17d1f1a724c6ec509d181ae4427113e9d3b5e6

1 files changed, 15 insertions, 30 deletions

diff --git a/init/builtins.cpp b/init/builtins.cpp
index 3bbaf8336..d0e56ec0c 100644
--- a/init/builtins.cpp
+++ b/init/builtins.cpp
@@ -29,7 +29,7 @@
 #include <sys/wait.h>
 #include <unistd.h>
 #include <linux/loop.h>
-#include <ext4_crypt.h>
+#include <ext4_crypt_init_extensions.h>
 
 #include <selinux/selinux.h>
 #include <selinux/label.h>
@@ -386,18 +386,6 @@ static int wipe_data_via_recovery()
 }
 
 /*
- * Callback to make a directory from the ext4 code
- */
-static int do_mount_alls_make_dir(const char* dir)
-{
-    if (make_dir(dir, 0700) && errno != EEXIST) {
-        return -1;
-    }
-
-    return 0;
-}
-
-/*
  * This function might request a reboot, in which case it will
  * not return.
  */
@@ -465,22 +453,6 @@ int do_mount_all(int nargs, char **args)
         ret = wipe_data_via_recovery();
         /* If reboot worked, there is no return. */
     } else if (ret == FS_MGR_MNTALL_DEV_DEFAULT_FILE_ENCRYPTED) {
-        // We have to create the key files here. Only init can call make_dir,
-        // and we can't do it from fs_mgr as then fs_mgr would depend on
-        // make_dir creating a circular dependency.
-        fstab = fs_mgr_read_fstab(args[1]);
-        for (int i = 0; i < fstab->num_entries; ++i) {
-            if (fs_mgr_is_file_encrypted(&fstab->recs[i])) {
-              if (e4crypt_create_device_key(fstab->recs[i].mount_point,
-                                            do_mount_alls_make_dir)) {
-                    ERROR("Could not create device key on %s"
-                          " - continue unencrypted\n",
-                          fstab->recs[i].mount_point);
-                }
-            }
-        }
-        fs_mgr_free_fstab(fstab);
-
         if (e4crypt_install_keyring()) {
             return -1;
         }
@@ -849,10 +821,23 @@ int do_wait(int nargs, char **args)
         return -1;
 }
 
+/*
+ * Callback to make a directory from the ext4 code
+ */
+static int do_installkeys_ensure_dir_exists(const char* dir)
+{
+    if (make_dir(dir, 0700) && errno != EEXIST) {
+        return -1;
+    }
+
+    return 0;
+}
+
 int do_installkey(int nargs, char **args)
 {
     if (nargs == 2) {
-        return e4crypt_install_key(args[1]);
+      return e4crypt_create_device_key(args[1],
+                                       do_installkeys_ensure_dir_exists);
     }
 
     return -1;