From 5684f61fe2a92cfa2c1250481201d9970d1e0f19 Mon Sep 17 00:00:00 2001
From: Neil Fuller <nfuller@google.com>
Date: Fri, 24 Feb 2017 19:03:58 +0000
Subject: [PATCH] Allow the shell user to run tzdatacheck
Allow the shell user to run tzdatacheck, which is required
to enable a new host side test.
This change also adds some additional checks to
tzdatacheck.te to ensure that OEMs opening up permissions
further don't accidentally create a security hole.
Bug: 31008728
Test: Ran CTS
Change-Id: I6ebfb467526b6b2ea08f891420eea24c81ed1e36
---
public/shell.te | 1 +
public/tzdatacheck.te | 12 ++++++++++++
2 files changed, 13 insertions(+)
diff --git a/public/shell.te b/public/shell.te
index ee8cf2a03..ee498911e 100644
--- a/public/shell.te
+++ b/public/shell.te
@@ -46,6 +46,7 @@ allow shell input_device:chr_file rw_file_perms;
r_dir_file(shell, system_file)
allow shell system_file:file x_file_perms;
allow shell toolbox_exec:file rx_file_perms;
+allow shell tzdatacheck_exec:file rx_file_perms;
allow shell shell_exec:file rx_file_perms;
allow shell zygote_exec:file rx_file_perms;
diff --git a/public/tzdatacheck.te b/public/tzdatacheck.te
index 93ae16529..6f60c8e2a 100644
--- a/public/tzdatacheck.te
+++ b/public/tzdatacheck.te
@@ -4,3 +4,15 @@ type tzdatacheck_exec, exec_type, file_type;
allow tzdatacheck zoneinfo_data_file:dir create_dir_perms;
allow tzdatacheck zoneinfo_data_file:file unlink;
+
+# Below are strong assertion that only init, system_server and tzdatacheck
+# can modify the /data time zone rules directories. This is to make it very
+# clear that only these domains should modify the actual time zone rules data.
+# The tzdatacheck binary itself may be executed by shell for tests but it must
+# not be able to modify the real rules.
+# If other users / binaries could modify time zone rules on device this might
+# have negative implications for users (who may get incorrect local times)
+# or break assumptions made / invalidate data held by the components actually
+# responsible for updating time zone rules.
+neverallow { domain -system_server -init -tzdatacheck } zoneinfo_data_file:file no_w_file_perms;
+neverallow { domain -system_server -init -tzdatacheck } zoneinfo_data_file:dir no_w_dir_perms;
--
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