private/isolated_app.te

###
### Services with isolatedProcess=true in their manifest.
###
### This file defines the rules for isolated apps. An "isolated
### app" is an APP with UID between AID_ISOLATED_START (99000)
### and AID_ISOLATED_END (99999).
###

app_domain(isolated_app)

# Access already open app data files received over Binder or local socket IPC.
allow isolated_app app_data_file:file { append read write getattr lock };

allow isolated_app activity_service:service_manager find;
allow isolated_app display_service:service_manager find;
allow isolated_app webviewupdate_service:service_manager find;

# Google Breakpad (crash reporter for Chrome) relies on ptrace
# functionality. Without the ability to ptrace, the crash reporter
# tool is broken.
# b/20150694
# https://code.google.com/p/chromium/issues/detail?id=475270
allow isolated_app self:process ptrace;

# b/32896414: Allow accessing sdcard file descriptors passed to isolated_apps
# by other processes. Open should never be allowed, and is blocked by
# neverallow rules below.
# TODO: consider removing write/append. We want to limit isolated_apps
# ability to mutate files of any type.
# media_rw_data_file is included for sdcardfs, and can be removed if sdcardfs
# is modified to change the secontext when accessing the lower filesystem.
allow isolated_app { sdcard_type media_rw_data_file }:file { read write append getattr lock };
auditallow isolated_app { sdcard_type media_rw_data_file }:file { write append };

# For webviews, isolated_app processes can be forked from the webview_zygote
# in addition to the zygote. Allow access to resources inherited from the
# webview_zygote process. These rules are specialized copies of the ones in app.te.
# Inherit FDs from the webview_zygote.
allow isolated_app webview_zygote:fd use;
# Notify webview_zygote of child death.
allow isolated_app webview_zygote:process sigchld;
# Inherit logd write socket.
allow isolated_app webview_zygote:unix_dgram_socket write;
# Read system properties managed by webview_zygote.
allow isolated_app webview_zygote_tmpfs:file read;

#####
##### Neverallow
#####

# Do not allow isolated_app to directly open tun_device
neverallow isolated_app tun_device:chr_file open;

# Do not allow isolated_app to set system properties.
neverallow isolated_app property_socket:sock_file write;
neverallow isolated_app property_type:property_service set;

# Isolated apps should not directly open app data files themselves.
neverallow isolated_app app_data_file:file open;

# Only allow appending to /data/anr/traces.txt (b/27853304, b/18340553)
# TODO: are there situations where isolated_apps write to this file?
# TODO: should we tighten these restrictions further?
neverallow isolated_app anr_data_file:file ~{ open append };
neverallow isolated_app anr_data_file:dir ~search;

# b/17487348
# Isolated apps can only access three services,
# activity_service, display_service and webviewupdate_service.
neverallow isolated_app {
    service_manager_type
    -activity_service
    -display_service
    -webviewupdate_service
}:service_manager find;

# Isolated apps shouldn't be able to access the driver directly.
neverallow isolated_app gpu_device:chr_file { rw_file_perms execute };

# Do not allow isolated_app access to /cache
neverallow isolated_app cache_file:dir ~{ r_dir_perms };
neverallow isolated_app cache_file:file ~{ read getattr };

# Restrict socket ioctls. Either 1. disallow privileged ioctls, 2. disallow the
# ioctl permission, or 3. disallow the socket class.
neverallowxperm isolated_app domain:{ rawip_socket tcp_socket udp_socket } ioctl priv_sock_ioctls;
neverallow isolated_app *:{ netlink_route_socket netlink_selinux_socket } ioctl;
neverallow isolated_app *:{
  socket netlink_socket packet_socket key_socket appletalk_socket
  netlink_firewall_socket netlink_tcpdiag_socket netlink_nflog_socket
  netlink_xfrm_socket netlink_audit_socket netlink_ip6fw_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
} *;

# Do not allow isolated_app to access external storage, except for files passed
# via file descriptors (b/32896414).
neverallow isolated_app { storage_file mnt_user_file sdcard_type }:dir ~getattr;
neverallow isolated_app { storage_file mnt_user_file }:file_class_set *;
neverallow isolated_app sdcard_type:{ devfile_class_set lnk_file sock_file fifo_file } *;
neverallow isolated_app sdcard_type:file ~{ read write append getattr lock };

# Do not allow USB access
neverallow isolated_app { usb_device usbaccessory_device }:chr_file *;

# Restrict the webview_zygote control socket.
neverallow isolated_app webview_zygote_socket:sock_file write;

# Avoid reads from generically labeled /proc files
# Create a more specific label if needed
neverallow isolated_app proc:file { no_rw_file_perms no_x_file_perms };