wpa_supplicant: Remove unnecessary permissions from system_server

Now that the android wifi framework has fully switched over to HIDL,
remove the sepolicy permissions for accessing wpa_supplicant using
socket control interface.

While there, also removed the redundant |hwbinder_use|.

Bug: 35707797
Test: Device boots up and able to connect to wifi networks.
Test: Wifi integration tests passed.
Change-Id: I55e24b852558d1a905b189116879179d62bdc76c

private/system_server.te

@@ -14,10 +14,6 @@ type_transition system_server system_data_file:sock_file system_ndebug_socket "n
 
 allow system_server zygote_tmpfs:file read;
 
-# 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;
-
 # For art.
 allow system_server dalvikcache_data_file:dir r_dir_perms;
 allow system_server dalvikcache_data_file:file { r_file_perms execute };
@@ -151,8 +147,6 @@ unix_socket_connect(system_server, vold, vold)
 unix_socket_connect(system_server, webview_zygote, webview_zygote)
 unix_socket_connect(system_server, zygote, zygote)
 unix_socket_connect(system_server, racoon, racoon)
-# TODO(b/35707797): Remove this socket access.
-unix_socket_send(system_server, wpa, hal_wifi_supplicant_server)
 unix_socket_connect(system_server, uncrypt, uncrypt)
 
 # Communicate over a socket created by surfaceflinger.
@@ -423,13 +417,6 @@ get_prop(system_server, serialno_prop)
 # Read/write the property which keeps track of whether this is the first start of system_server
 set_prop(system_server, firstboot_prop)
 
-# Create a socket for receiving info from wpa.
-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
-allow system_server wpa_socket:sock_file unlink;
-
 # Create a socket for connections from debuggerd.
 allow system_server system_ndebug_socket:sock_file create_file_perms;
 

public/hal_wifi_supplicant.te

@@ -18,12 +18,6 @@ allow hal_wifi_supplicant self:packet_socket create_socket_perms;
 allowxperm hal_wifi_supplicant self:packet_socket ioctl { unpriv_sock_ioctls priv_sock_ioctls unpriv_tty_ioctls };
 allow hal_wifi_supplicant wifi_data_file:dir create_dir_perms;
 allow hal_wifi_supplicant wifi_data_file:file create_file_perms;
-# TODO(b/35707797): Remove this socket access.
-unix_socket_send(hal_wifi_supplicant, system_wpa, system_server)
-
-# HIDL interface exposed by WPA.
-hwbinder_use(hal_wifi_supplicant)
-binder_call(hal_wifi_supplicant, system_server)
 
 # Create a socket for receiving info from wpa
 allow hal_wifi_supplicant wpa_socket:dir create_dir_perms;