1# webview_zygote is an auxiliary zygote process that is used to spawn 2# isolated_app processes for rendering untrusted web content. 3 4typeattribute webview_zygote coredomain; 5 6# The webview_zygote needs to be able to transition domains. 7typeattribute webview_zygote mlstrustedsubject; 8 9# Allow access to temporary files, which is normally permitted through 10# a domain macro. 11tmpfs_domain(webview_zygote); 12 13userfaultfd_use(webview_zygote) 14 15# Allow reading/executing installed binaries to enable preloading the 16# installed WebView implementation. 17allow webview_zygote apk_data_file:dir r_dir_perms; 18allow webview_zygote apk_data_file:file { r_file_perms execute }; 19 20# Access to the WebView relro file. 21allow webview_zygote shared_relro_file:dir search; 22allow webview_zygote shared_relro_file:file r_file_perms; 23 24# Set the UID/GID of the process. 25allow webview_zygote self:global_capability_class_set { setgid setuid }; 26# Drop capabilities from bounding set. 27allow webview_zygote self:global_capability_class_set setpcap; 28# Switch SELinux context to app domains. 29allow webview_zygote self:process setcurrent; 30allow webview_zygote isolated_app:process dyntransition; 31 32# For art. 33allow webview_zygote { apex_art_data_file dalvikcache_data_file }:dir r_dir_perms; 34allow webview_zygote dalvikcache_data_file:lnk_file r_file_perms; 35allow webview_zygote { apex_art_data_file dalvikcache_data_file }:file { r_file_perms execute }; 36allow webview_zygote apex_module_data_file:dir search; 37 38# To load overlay from /apex (vendor APEXes) 39allow webview_zygote vendor_apex_metadata_file:dir search; 40 41# Allow webview_zygote to create JIT memory. 42allow webview_zygote self:process execmem; 43 44# Allow webview_zygote to stat the files that it opens. It must 45# be able to inspect them so that it can reopen them on fork 46# if necessary: b/30963384. 47allow webview_zygote debugfs_trace_marker:file getattr; 48 49# Allow webview_zygote to manage the pgroup of its children. 50allow webview_zygote system_server:process getpgid; 51 52# Interaction between the webview_zygote and its children. 53allow webview_zygote isolated_app:process setpgid; 54 55# TODO (b/63631799) fix this access 56# Suppress denials to storage. Webview zygote should not be accessing. 57dontaudit webview_zygote mnt_expand_file:dir getattr; 58 59# TODO (b/72957399) remove this when webview_zygote is reparented to 60# app_process zygote 61dontaudit webview_zygote dex2oat_exec:file execute; 62 63# Get seapp_contexts 64allow webview_zygote seapp_contexts_file:file r_file_perms; 65# Check validity of SELinux context before use. 66selinux_check_context(webview_zygote) 67# Check SELinux permissions. 68selinux_check_access(webview_zygote) 69 70# Directory listing in /system. 71allow webview_zygote system_file:dir r_dir_perms; 72 73# Read and inspect temporary files (like system properties) managed by zygote. 74allow webview_zygote zygote_tmpfs:file { read getattr }; 75# Child of zygote. 76allow webview_zygote zygote:fd use; 77allow webview_zygote zygote:process sigchld; 78 79# Allow apps access to /vendor/overlay 80r_dir_file(webview_zygote, vendor_overlay_file) 81 82allow webview_zygote same_process_hal_file:file { execute read open getattr map }; 83 84allow webview_zygote system_data_file:lnk_file r_file_perms; 85 86# Send unsolicited message to system_server 87unix_socket_send(webview_zygote, system_unsolzygote, system_server) 88 89# Allow the webview_zygote to access the runtime feature flag properties. 90get_prop(webview_zygote, device_config_runtime_native_prop) 91get_prop(webview_zygote, device_config_runtime_native_boot_prop) 92 93# Allow webview_zygote to access odsign verification status 94get_prop(zygote, odsign_prop) 95 96# /data/resource-cache 97allow webview_zygote resourcecache_data_file:file r_file_perms; 98allow webview_zygote resourcecache_data_file:dir r_dir_perms; 99 100##### 101##### Neverallow 102##### 103 104# Only permit transition to isolated_app. 105neverallow webview_zygote { domain -isolated_app }:process dyntransition; 106 107# Only setcon() transitions, no exec() based transitions, except for crash_dump. 108neverallow webview_zygote { domain -crash_dump }:process transition; 109 110# Must not exec() a program without changing domains. 111# Having said that, exec() above is not allowed. 112neverallow webview_zygote *:file execute_no_trans; 113 114# The only way to enter this domain is for the zygote to fork a new 115# webview_zygote child. 116neverallow { domain -zygote } webview_zygote:process dyntransition; 117 118# Disallow write access to properties. 119neverallow webview_zygote property_socket:sock_file write; 120neverallow webview_zygote property_type:property_service set; 121 122# Should not have any access to app data files. 123neverallow webview_zygote app_data_file_type:file { rwx_file_perms }; 124 125neverallow webview_zygote { 126 service_manager_type 127 -activity_service 128 -webviewupdate_service 129}:service_manager find; 130 131# Isolated apps shouldn't be able to access the driver directly. 132neverallow webview_zygote gpu_device:chr_file { rwx_file_perms }; 133 134# Do not allow webview_zygote access to /cache. 135neverallow webview_zygote cache_file:dir ~{ r_dir_perms }; 136neverallow webview_zygote cache_file:file ~{ read getattr }; 137 138# Do not allow most socket access. This is socket_class_set, excluding unix_dgram_socket, 139# unix_stream_socket, and netlink_selinux_socket. 140neverallow webview_zygote domain:{ 141 socket tcp_socket udp_socket rawip_socket netlink_socket packet_socket key_socket 142 appletalk_socket netlink_route_socket netlink_tcpdiag_socket 143 netlink_nflog_socket netlink_xfrm_socket netlink_audit_socket 144 netlink_dnrt_socket netlink_kobject_uevent_socket tun_socket netlink_iscsi_socket 145 netlink_fib_lookup_socket netlink_connector_socket netlink_netfilter_socket 146 netlink_generic_socket netlink_scsitransport_socket netlink_rdma_socket netlink_crypto_socket 147 sctp_socket icmp_socket ax25_socket ipx_socket netrom_socket atmpvc_socket 148 x25_socket rose_socket decnet_socket atmsvc_socket rds_socket irda_socket 149 pppox_socket llc_socket can_socket tipc_socket bluetooth_socket iucv_socket 150 rxrpc_socket isdn_socket phonet_socket ieee802154_socket caif_socket 151 alg_socket nfc_socket vsock_socket kcm_socket qipcrtr_socket smc_socket 152 xdp_socket 153} *; 154 155# Do not allow access to Bluetooth-related system properties. 156# neverallow rules for Bluetooth-related data files are listed above. 157neverallow webview_zygote { 158 bluetooth_a2dp_offload_prop 159 bluetooth_audio_hal_prop 160 bluetooth_prop 161 exported_bluetooth_prop 162}:file create_file_perms; 163