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