1# only HALs responsible for network hardware should have privileged 2# network capabilities 3neverallow { 4 halserverdomain 5 -hal_bluetooth_server 6 -hal_can_controller_server 7 -hal_wifi_server 8 -hal_wifi_hostapd_server 9 -hal_wifi_supplicant_server 10 -hal_telephony_server 11 -hal_uwb_server 12} self:global_capability_class_set { net_admin net_raw }; 13 14# Unless a HAL's job is to communicate over the network, or control network 15# hardware, it should not be using network sockets. 16# NOTE: HALs for automotive devices have an exemption from this rule because in 17# a car it is common to have external modules and HALs need to communicate to 18# those modules using network. Using this exemption for non-automotive builds 19# will result in CTS failure. 20neverallow { 21 halserverdomain 22 -hal_automotive_socket_exemption 23 -hal_can_controller_server 24 -hal_tetheroffload_server 25 -hal_wifi_server 26 -hal_wifi_hostapd_server 27 -hal_wifi_supplicant_server 28 -hal_telephony_server 29 -hal_uwb_server 30} domain:{ tcp_socket udp_socket rawip_socket } *; 31 32# The UWB HAL is not actually a networking HAL but may need to bring up and down 33# interfaces. Restrict it to only these networking operations. 34neverallow hal_uwb_server self:global_capability_class_set { net_raw }; 35 36# Subset of socket_class_set likely to be usable for communication or accessible through net_admin. 37# udp_socket is required to use interface ioctls. 38neverallow hal_uwb_server domain:{ socket tcp_socket rawip_socket netlink_socket packet_socket key_socket netlink_route_socket netlink_tcpdiag_socket netlink_nflog_socket netlink_xfrm_socket netlink_selinux_socket netlink_audit_socket netlink_dnrt_socket netlink_kobject_uevent_socket tun_socket netlink_iscsi_socket netlink_fib_lookup_socket netlink_connector_socket netlink_netfilter_socket netlink_scsitransport_socket netlink_rdma_socket netlink_crypto_socket qipcrtr_socket xdp_socket } *; 39 40### 41# HALs are defined as an attribute and so a given domain could hypothetically 42# have multiple HALs in it (or even all of them) with the subsequent policy of 43# the domain comprised of the union of all the HALs. 44# 45# This is a problem because 46# 1) Security sensitive components should only be accessed by specific HALs. 47# 2) hwbinder_call and the restrictions it provides cannot be reasoned about in 48# the platform. 49# 3) The platform cannot reason about defense in depth if there are 50# monolithic domains etc. 51# 52# As an example, hal_keymaster and hal_gatekeeper can access the TEE and while 53# its OK for them to share a process its not OK with them to share processes 54# with other hals. 55# 56# The following neverallow rules, in conjuntion with CTS tests, assert that 57# these security principles are adhered to. 58# 59# Do not allow a hal to exec another process without a domain transition. 60# TODO remove exemptions. 61neverallow { 62 halserverdomain 63 -hal_dumpstate_server 64 -hal_telephony_server 65} { file_type fs_type }:file execute_no_trans; 66# Do not allow a process other than init to transition into a HAL domain. 67neverallow { domain -init } halserverdomain:process transition; 68# Only allow transitioning to a domain by running its executable. Do not 69# allow transitioning into a HAL domain by use of seclabel in an 70# init.*.rc script. 71neverallow * halserverdomain:process dyntransition; 72