Enable SELinux protections for netd.

This change does several things:

1) Restore domain.te to the version present at
cd516a32663b4eb11b2e3356b86450020e59e279 . This is the version
currently being distributed in AOSP.

2) Add "allow domain properties_device:file r_file_perms;" to
domain.te, to allow all domains to read /dev/__properties__ .
This change was missing from AOSP.

3) Restore netd.te to the version present at
80c9ba5267f1a6ceffcf979471d101948b520ad6 . This is the version
currently being distributed in AOSP.

4) Remove anything involving module loading from netd.te. CTS
enforces that Android kernels can't have module loading enabled.

5) Add several new capabilities, plus data file rules, to
netd.te, since netd needs to write to files owned by wifi.

6) Add a new unconfined domain called dnsmasq.te, and allow
transitions from netd to that domain. Over time, we'll tighten up
the dnsmasq.te domain.

7) Add a new unconfined domain called hostapd.te, and allow
transitions from netd to that domain. Over time, we'll tighten up
the hostapd.te domain.

The net effect of these changes is to re-enable SELinux protections
for netd. The policy is FAR from perfect, and allows a lot of wiggle
room, but we can improve it over time.

Testing: as much as possible, I've exercised networking related
functionality, including turning on and off wifi, entering airplane
mode, and enabling tethering and portable wifi hotspots. It's quite
possible I've missed something, and if we experience problems, I
can roll back this change.

Bug: 9618347
Change-Id: I23ff3eebcef629bc7baabcf6962f25f116c4a3c0

1 files changed, 44 insertions, 2 deletions

diff --git a/netd.te b/netd.te
index 6f294ed..3726ec4 100644
--- a/netd.te
+++ b/netd.te
@@ -2,7 +2,49 @@
 type netd, domain;
 type netd_exec, exec_type, file_type;
 
-permissive netd;
-unconfined_domain(netd)
 init_daemon_domain(netd)
+typeattribute netd mlstrustedsubject;
+allow netd self:capability { net_admin net_raw kill };
+allow netd self:netlink_kobject_uevent_socket *;
+allow netd self:netlink_route_socket *;
+allow netd self:netlink_nflog_socket *;
+allow netd self:rawip_socket *;
+allow netd self:udp_socket *;
+allow netd node:udp_socket node_bind;
+allow netd port:udp_socket name_bind;
+allow netd self:unix_stream_socket *;
+allow netd shell_exec:file rx_file_perms;
+allow netd system_file:file x_file_perms;
+allow netd devpts:chr_file rw_file_perms;
+
+# For /proc/sys/net/ipv[46]/route/flush.
+# XXX Split /proc/sys/net into its own type.
+allow netd proc:file write;
+
+# For /sys/modules/bcmdhd/parameters/firmware_path
+# XXX Split into its own type.
+allow netd sysfs:file write;
+
+# Set dhcp lease for PAN connection
+unix_socket_connect(netd, property, init)
+allow netd system_prop:property_service set;
+
+# Connect to PAN
 domain_auto_trans(netd, dhcp_exec, dhcp)
+allow netd dhcp:process signal;
+
+# Needed to update /data/misc/wifi/hostapd.conf
+# TODO: See what we can do to reduce the need for
+# these capabilities
+allow netd self:capability { dac_override chown fowner };
+allow netd wifi_data_file:file create_file_perms;
+allow netd wifi_data_file:dir rw_dir_perms;
+
+# Allow netd to spawn hostapd in it's own domain
+domain_auto_trans(netd, hostapd_exec, hostapd)
+allow netd hostapd:process signal;
+
+# Allow netd to spawn dnsmasq in it's own domain
+domain_auto_trans(netd, dnsmasq_exec, dnsmasq)
+allow netd dnsmasq:process signal;
+