From a9671c6b9eff0b72ad797e2339865bd24222391b Mon Sep 17 00:00:00 2001
From: Alex Deymo <deymo@google.com>
Date: Tue, 5 Apr 2016 16:07:25 -0700
Subject: [PATCH] Allow postinstall_file to be an entrypoint.
postinstall_file was an exec_type so it could be an entrypoint for the
domain_auto_trans from update_engine domain to postinstall domain. This
patch removes the exec_type from postinstall_file and exempts it from
the neverallow rule to become an entrypoint.
Bug: 28008031
TEST=postinstall_example still runs as the "postinstall" domain on edison-eng.
Change-Id: Icbf5b262c6f971ce054f1b4896c611b32a6d66b5
---
domain.te | 4 ++--
file.te | 2 +-
postinstall.te | 4 ++++
3 files changed, 7 insertions(+), 3 deletions(-)
diff --git a/domain.te b/domain.te
index de00ac1df..f0201059e 100644
--- a/domain.te
+++ b/domain.te
@@ -201,8 +201,8 @@ neverallow { domain -init } kernel:security setsecparam;
# Only init, ueventd and system_server should be able to access HW RNG
neverallow { domain -init -system_server -ueventd } hw_random_device:chr_file *;
-# Ensure that all entrypoint executables are in exec_type.
-neverallow * { file_type -exec_type }:file entrypoint;
+# Ensure that all entrypoint executables are in exec_type or postinstall_file.
+neverallow * { file_type -exec_type -postinstall_file }:file entrypoint;
# Ensure that nothing in userspace can access /dev/mem or /dev/kmem
neverallow { domain -kernel -ueventd -init } kmem_device:chr_file *;
diff --git a/file.te b/file.te
index b789e36e5..833e41a4f 100644
--- a/file.te
+++ b/file.te
@@ -117,7 +117,7 @@ type storage_stub_file, file_type;
# /postinstall: Mount point used by update_engine to run postinstall.
type postinstall_mnt_dir, file_type;
# Files inside the /postinstall mountpoint are all labeled as postinstall_file.
-type postinstall_file, file_type, exec_type;
+type postinstall_file, file_type;
# /data/misc subdirectories
type adb_keys_file, file_type, data_file_type;
diff --git a/postinstall.te b/postinstall.te
index 8afc56128..938fcd23f 100644
--- a/postinstall.te
+++ b/postinstall.te
@@ -18,3 +18,7 @@ allow postinstall postinstall_file:dir r_dir_perms;
allow postinstall shell_exec:file rx_file_perms;
allow postinstall system_file:file rx_file_perms;
allow postinstall toolbox_exec:file rx_file_perms;
+
+# No domain other than update_engine should transition to postinstall, as it is
+# only meant to run during the update.
+neverallow { domain -update_engine } postinstall:process { transition dyntransition };
--
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