# webview_zygote is an auxiliary zygote process that is used to spawn # isolated_app processes for rendering untrusted web content. typeattribute webview_zygote coredomain; # The webview_zygote needs to be able to transition domains. typeattribute webview_zygote mlstrustedsubject; # Allow access to temporary files, which is normally permitted through # a domain macro. tmpfs_domain(webview_zygote); userfaultfd_use(webview_zygote) # Allow reading/executing installed binaries to enable preloading the # installed WebView implementation. allow webview_zygote apk_data_file:dir r_dir_perms; allow webview_zygote apk_data_file:file { r_file_perms execute }; # Access to the WebView relro file. allow webview_zygote shared_relro_file:dir search; allow webview_zygote shared_relro_file:file r_file_perms; # Set the UID/GID of the process. allow webview_zygote self:global_capability_class_set { setgid setuid }; # Drop capabilities from bounding set. allow webview_zygote self:global_capability_class_set setpcap; # Switch SELinux context to app domains. allow webview_zygote self:process setcurrent; allow webview_zygote isolated_app:process dyntransition; # For art. allow webview_zygote { apex_art_data_file dalvikcache_data_file }:dir r_dir_perms; allow webview_zygote dalvikcache_data_file:lnk_file r_file_perms; allow webview_zygote { apex_art_data_file dalvikcache_data_file }:file { r_file_perms execute }; allow webview_zygote apex_module_data_file:dir search; # To load overlay from /apex (vendor APEXes) allow webview_zygote vendor_apex_metadata_file:dir search; # Allow webview_zygote to create JIT memory. allow webview_zygote self:process execmem; # Allow webview_zygote to stat the files that it opens. It must # be able to inspect them so that it can reopen them on fork # if necessary: b/30963384. allow webview_zygote debugfs_trace_marker:file getattr; # Allow webview_zygote to manage the pgroup of its children. allow webview_zygote system_server:process getpgid; # Interaction between the webview_zygote and its children. allow webview_zygote isolated_app:process setpgid; # TODO (b/63631799) fix this access # Suppress denials to storage. Webview zygote should not be accessing. dontaudit webview_zygote mnt_expand_file:dir getattr; # TODO (b/72957399) remove this when webview_zygote is reparented to # app_process zygote dontaudit webview_zygote dex2oat_exec:file execute; # Get seapp_contexts allow webview_zygote seapp_contexts_file:file r_file_perms; # Check validity of SELinux context before use. selinux_check_context(webview_zygote) # Check SELinux permissions. selinux_check_access(webview_zygote) # Directory listing in /system. allow webview_zygote system_file:dir r_dir_perms; # Read and inspect temporary files (like system properties) managed by zygote. allow webview_zygote zygote_tmpfs:file { read getattr }; # Child of zygote. allow webview_zygote zygote:fd use; allow webview_zygote zygote:process sigchld; # Allow apps access to /vendor/overlay r_dir_file(webview_zygote, vendor_overlay_file) allow webview_zygote same_process_hal_file:file { execute read open getattr map }; allow webview_zygote system_data_file:lnk_file r_file_perms; # Send unsolicited message to system_server unix_socket_send(webview_zygote, system_unsolzygote, system_server) # Allow the webview_zygote to access the runtime feature flag properties. get_prop(webview_zygote, device_config_runtime_native_prop) get_prop(webview_zygote, device_config_runtime_native_boot_prop) # Allow webview_zygote to access odsign verification status get_prop(zygote, odsign_prop) # /data/resource-cache allow webview_zygote resourcecache_data_file:file r_file_perms; allow webview_zygote resourcecache_data_file:dir r_dir_perms; ##### ##### Neverallow ##### # Only permit transition to isolated_app. neverallow webview_zygote { domain -isolated_app }:process dyntransition; # Only setcon() transitions, no exec() based transitions, except for crash_dump. neverallow webview_zygote { domain -crash_dump }:process transition; # Must not exec() a program without changing domains. # Having said that, exec() above is not allowed. neverallow webview_zygote *:file execute_no_trans; # The only way to enter this domain is for the zygote to fork a new # webview_zygote child. neverallow { domain -zygote } webview_zygote:process dyntransition; # Disallow write access to properties. neverallow webview_zygote property_socket:sock_file write; neverallow webview_zygote property_type:property_service set; # Should not have any access to app data files. neverallow webview_zygote app_data_file_type:file { rwx_file_perms }; neverallow webview_zygote { service_manager_type -activity_service -webviewupdate_service }:service_manager find; # Isolated apps shouldn't be able to access the driver directly. neverallow webview_zygote gpu_device:chr_file { rwx_file_perms }; # Do not allow webview_zygote access to /cache. neverallow webview_zygote cache_file:dir ~{ r_dir_perms }; neverallow webview_zygote cache_file:file ~{ read getattr }; # Do not allow most socket access. This is socket_class_set, excluding unix_dgram_socket, # unix_stream_socket, and netlink_selinux_socket. neverallow webview_zygote domain:{ socket tcp_socket udp_socket rawip_socket netlink_socket packet_socket key_socket appletalk_socket netlink_route_socket netlink_tcpdiag_socket netlink_nflog_socket netlink_xfrm_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_generic_socket netlink_scsitransport_socket netlink_rdma_socket netlink_crypto_socket sctp_socket icmp_socket ax25_socket ipx_socket netrom_socket atmpvc_socket x25_socket rose_socket decnet_socket atmsvc_socket rds_socket irda_socket pppox_socket llc_socket can_socket tipc_socket bluetooth_socket iucv_socket rxrpc_socket isdn_socket phonet_socket ieee802154_socket caif_socket alg_socket nfc_socket vsock_socket kcm_socket qipcrtr_socket smc_socket xdp_socket } *; # Do not allow access to Bluetooth-related system properties. # neverallow rules for Bluetooth-related data files are listed above. neverallow webview_zygote { bluetooth_a2dp_offload_prop bluetooth_audio_hal_prop bluetooth_prop exported_bluetooth_prop }:file create_file_perms;