Label /data/misc/wifi/sockets with wpa_socket.

This will ensure that any sockets created in this directory
will default to wpa_socket unless a type_transition is defined.
Define a type transition for system_server to keep its separate
system_wpa_socket type assigned for its socket.  Allow wpa
to create and unlink sockets in the directory.  We leave the
already existing rules for wifi_data_file in place for compatibility
with existing devices that have wifi_data_file on /data/misc/wifi/sockets.

Change-Id: I9e35cc93abf89ce3594860aa3193f84a3b42ea6e
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>

file_contexts

@@ -186,6 +186,8 @@
 /data/misc/systemkeys(/.*)?     u:object_r:systemkeys_data_file:s0
 /data/misc/vpn(/.*)?            u:object_r:vpn_data_file:s0
 /data/misc/wifi(/.*)?           u:object_r:wifi_data_file:s0
+/data/misc/wifi/sockets(/.*)?   u:object_r:wpa_socket:s0
+/data/misc/wifi/sockets/wpa_ctrl.*   u:object_r:system_wpa_socket:s0
 /data/misc/zoneinfo(/.*)?       u:object_r:zoneinfo_data_file:s0
 
 # App sandboxes

system_server.te

@@ -173,6 +173,8 @@ allow system_server ctl_default_prop:property_service set;
 
 # Create a socket for receiving info from wpa.
 type_transition system_server wifi_data_file:sock_file system_wpa_socket;
+type_transition system_server wpa_socket:sock_file system_wpa_socket;
+allow system_server wpa_socket:dir rw_dir_perms;
 allow system_server system_wpa_socket:sock_file create_file_perms;
 
 # Remove sockets created by wpa_supplicant

wpa_supplicant.te

@@ -17,4 +17,5 @@ allow wpa random_device:chr_file r_file_perms;
 
 # Create a socket for receiving info from wpa
 type_transition wpa wifi_data_file:sock_file wpa_socket;
+allow wpa wpa_socket:dir { rw_dir_perms setattr };
 allow wpa wpa_socket:sock_file create_file_perms;