platform_system_sepolicy/private/webview_zygote.te
Chris Morin 9644df47a3 prevent benign dex2oat selinux denial temporarily
Since we now call patchoat --verify in zygote art loading code, we have
the unintended effect of webview zygote calling patchoat --verify. This
is undesireable since webview zygote doesn't need to verify the .art
files after the app_process zygote has already done so. The exec of
patchoat fails for webview zygote, and this change hides that. This
change should be reverted when b/72957399 is resolved.

Bug: 66697305
Test: Ensure no new selinux denials were introduced.
Change-Id: I4152edc920e5c436516b958b8c861dcc1c4751d8
2018-02-05 14:26:04 -08:00

127 lines
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# 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;
# When init launches the WebView zygote's executable, transition the
# resulting process into webview_zygote domain.
init_daemon_domain(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 dalvikcache_data_file:dir r_dir_perms;
allow webview_zygote dalvikcache_data_file:lnk_file r_file_perms;
allow webview_zygote dalvikcache_data_file:file { r_file_perms execute };
# 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;
#####
##### 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 init to exec() us.
neverallow { domain -init } webview_zygote:process transition;
neverallow * 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
system_app_data_file
bluetooth_data_file
nfc_data_file
radio_data_file
shell_data_file
}: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
} *;
# Do not allow access to Bluetooth-related system properties.
# neverallow rules for Bluetooth-related data files are listed above.
neverallow webview_zygote bluetooth_prop:file create_file_perms;