23c9d91b46
Currently, both untrusted apps and priv-apps use the SELinux file label
"app_data_file" for files in their /data/data directory. This is
problematic, as we really want different rules for such files. For
example, we may want to allow untrusted apps to load executable code
from priv-app directories, but disallow untrusted apps from loading
executable code from their own home directories.
This change adds a new file type "privapp_data_file". For compatibility,
we adjust the policy to support access privapp_data_files almost
everywhere we were previously granting access to app_data_files
(adbd and run-as being exceptions). Additional future tightening is
possible here by removing some of these newly added rules.
This label will start getting used in a followup change to
system/sepolicy/private/seapp_contexts, similar to:
-user=_app isPrivApp=true domain=priv_app type=app_data_file levelFrom=user
+user=_app isPrivApp=true domain=priv_app type=privapp_data_file levelFrom=user
For now, this newly introduced label has no usage, so this change
is essentially a no-op.
Test: Factory reset and boot - no problems on fresh install.
Test: Upgrade to new version and test. No compatibility problems on
filesystem upgrade.
Change-Id: I9618b7d91d1c2bcb5837cdabc949f0cf741a2837
141 lines
5.3 KiB
Text
141 lines
5.3 KiB
Text
# webview_zygote is an auxiliary zygote process that is used to spawn
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# isolated_app processes for rendering untrusted web content.
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typeattribute webview_zygote coredomain;
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# The webview_zygote needs to be able to transition domains.
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typeattribute webview_zygote mlstrustedsubject;
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# Allow access to temporary files, which is normally permitted through
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# a domain macro.
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tmpfs_domain(webview_zygote);
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# Allow reading/executing installed binaries to enable preloading the
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# installed WebView implementation.
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allow webview_zygote apk_data_file:dir r_dir_perms;
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allow webview_zygote apk_data_file:file { r_file_perms execute };
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# Access to the WebView relro file.
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allow webview_zygote shared_relro_file:dir search;
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allow webview_zygote shared_relro_file:file r_file_perms;
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# Set the UID/GID of the process.
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allow webview_zygote self:global_capability_class_set { setgid setuid };
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# Drop capabilities from bounding set.
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allow webview_zygote self:global_capability_class_set setpcap;
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# Switch SELinux context to app domains.
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allow webview_zygote self:process setcurrent;
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allow webview_zygote isolated_app:process dyntransition;
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# For art.
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allow webview_zygote dalvikcache_data_file:dir r_dir_perms;
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allow webview_zygote dalvikcache_data_file:lnk_file r_file_perms;
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allow webview_zygote dalvikcache_data_file:file { r_file_perms execute };
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# Allow webview_zygote to stat the files that it opens. It must
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# be able to inspect them so that it can reopen them on fork
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# if necessary: b/30963384.
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allow webview_zygote debugfs_trace_marker:file getattr;
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# Allow webview_zygote to manage the pgroup of its children.
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allow webview_zygote system_server:process getpgid;
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# Interaction between the webview_zygote and its children.
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allow webview_zygote isolated_app:process setpgid;
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# TODO (b/63631799) fix this access
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# Suppress denials to storage. Webview zygote should not be accessing.
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dontaudit webview_zygote mnt_expand_file:dir getattr;
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# TODO (b/72957399) remove this when webview_zygote is reparented to
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# app_process zygote
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dontaudit webview_zygote dex2oat_exec:file execute;
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# Get seapp_contexts
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allow webview_zygote seapp_contexts_file:file r_file_perms;
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# Check validity of SELinux context before use.
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selinux_check_context(webview_zygote)
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# Check SELinux permissions.
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selinux_check_access(webview_zygote)
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# Directory listing in /system.
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allow webview_zygote system_file:dir r_dir_perms;
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# Read system properties managed by zygote.
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allow webview_zygote zygote_tmpfs:file read;
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# Child of zygote.
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allow webview_zygote zygote:fd use;
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allow webview_zygote zygote:process sigchld;
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# Allow apps access to /vendor/overlay
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r_dir_file(webview_zygote, vendor_overlay_file)
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#####
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##### Neverallow
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#####
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# Only permit transition to isolated_app.
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neverallow webview_zygote { domain -isolated_app }:process dyntransition;
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# Only setcon() transitions, no exec() based transitions, except for crash_dump.
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neverallow webview_zygote { domain -crash_dump }:process transition;
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# Must not exec() a program without changing domains.
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# Having said that, exec() above is not allowed.
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neverallow webview_zygote *:file execute_no_trans;
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# The only way to enter this domain is for the zygote to fork a new
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# webview_zygote child.
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neverallow { domain -zygote } webview_zygote:process dyntransition;
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# Disallow write access to properties.
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neverallow webview_zygote property_socket:sock_file write;
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neverallow webview_zygote property_type:property_service set;
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# Should not have any access to app data files.
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neverallow webview_zygote {
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app_data_file
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privapp_data_file
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system_app_data_file
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bluetooth_data_file
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nfc_data_file
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radio_data_file
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shell_data_file
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}:file { rwx_file_perms };
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neverallow webview_zygote {
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service_manager_type
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-activity_service
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-webviewupdate_service
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}:service_manager find;
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# Isolated apps shouldn't be able to access the driver directly.
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neverallow webview_zygote gpu_device:chr_file { rwx_file_perms };
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# Do not allow webview_zygote access to /cache.
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neverallow webview_zygote cache_file:dir ~{ r_dir_perms };
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neverallow webview_zygote cache_file:file ~{ read getattr };
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# Do not allow most socket access. This is socket_class_set, excluding unix_dgram_socket,
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# unix_stream_socket, and netlink_selinux_socket.
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neverallow webview_zygote domain:{
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socket tcp_socket udp_socket rawip_socket netlink_socket packet_socket key_socket
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appletalk_socket netlink_route_socket netlink_tcpdiag_socket
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netlink_nflog_socket netlink_xfrm_socket netlink_audit_socket
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netlink_dnrt_socket netlink_kobject_uevent_socket tun_socket netlink_iscsi_socket
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netlink_fib_lookup_socket netlink_connector_socket netlink_netfilter_socket
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netlink_generic_socket netlink_scsitransport_socket netlink_rdma_socket netlink_crypto_socket
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sctp_socket icmp_socket ax25_socket ipx_socket netrom_socket atmpvc_socket
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x25_socket rose_socket decnet_socket atmsvc_socket rds_socket irda_socket
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pppox_socket llc_socket can_socket tipc_socket bluetooth_socket iucv_socket
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rxrpc_socket isdn_socket phonet_socket ieee802154_socket caif_socket
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alg_socket nfc_socket vsock_socket kcm_socket qipcrtr_socket smc_socket
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} *;
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# Do not allow access to Bluetooth-related system properties.
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# neverallow rules for Bluetooth-related data files are listed above.
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neverallow webview_zygote {
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bluetooth_a2dp_offload_prop
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bluetooth_prop
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exported_bluetooth_prop
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}:file create_file_perms;
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