system_server: neverallow blk_file read/write
With the exception of the factory reset protection block device,
don't allow system_server to read or write to any other block
devices. This helps protect against a system->root escalation
when system_server has the ability to directly minipulate raw
block devices / partitions / partition tables.
This change adds a neverallow rule, which is a compile time
assertion that no SELinux policy is written which allows this
access. No new rules are added or removed.
Change-Id: I388408423097ef7cf4950197b79d4be9d666362c
diff --git a/neverallow_macros b/neverallow_macros
index 3593dd1..b36cceb 100644
--- a/neverallow_macros
+++ b/neverallow_macros
@@ -1,5 +1,6 @@
#
# Common neverallow permissions
define(`no_w_file_perms', `{ append create link unlink relabelfrom rename setattr write }')
+define(`no_rw_file_perms', `{ no_w_file_perms open read ioctl lock }')
define(`no_x_file_perms', `{ execute execute_no_trans }')
define(`no_w_dir_perms', `{ add_name create link relabelfrom remove_name rename reparent rmdir setattr write }')