Allow update_verifier to access bootctrl_block_device.

Bug: 26039641
Change-Id: Ifd96b105f054b67f881529db3fe94718cab4a0f4
(cherry picked from commit 8eaf2585)

device.te

@@ -96,3 +96,6 @@ type metadata_block_device, dev_type;
 
 # The 'misc' partition used by recovery and A/B.
 type misc_block_device, dev_type;
+
+# Bootctrl block device used by A/B update (update_engine, update_verifier).
+type bootctrl_block_device, dev_type;

file_contexts

@@ -187,6 +187,7 @@
 /system/bin/inputflinger u:object_r:inputflinger_exec:s0
 /system/bin/logd        u:object_r:logd_exec:s0
 /system/bin/uncrypt     u:object_r:uncrypt_exec:s0
+/system/bin/update_verifier u:object_r:update_verifier_exec:s0
 /system/bin/logwrapper  u:object_r:system_file:s0
 /system/bin/vdc         u:object_r:vdc_exec:s0
 /system/bin/install-recovery.sh u:object_r:install_recovery_exec:s0

update_verifier.te

+# update_verifier
+type update_verifier, domain;
+type update_verifier_exec, exec_type, file_type;
+
+init_daemon_domain(update_verifier)
+
+# Raw writes to bootctrl block device
+allow update_verifier bootctrl_block_device:blk_file rw_file_perms;
+
+# TODO: Add rules to allow update_verifier to read system_block_device.