e1ddd741de
system/sepolicy commit23c9d91b46introduced a new type called privapp_data_file. This type is used to label priv-app's /home files. For backwards compatibility, priv-app rules involving normal app_data_files were preserved. Subsequently, system/sepolicy commit5d1755194aassigned the file label privapp_data_file to /home files owned by priv-apps. Because of the previous labeling of priv-app data files, priv-apps were granted the ability to mmap(PROT_EXEC) any other app's /home files, regardless of how trustworthy or untrustworthy those files were. Commit23c9d91b46preserved the status quo. However, now that we have a more refined label for priv-app /home files, we no longer need to be as permissive. Drop the ability for priv-apps to map executable code from untrusted_apps home directories. "execute" is removed in this change, and "execute_no_trans" was previously removed in commit8fb4cb8bc2. Add a neverallow assertion (compile time assertion + CTS test) to prevent regressions. Further clarify why we need to support priv-apps loading executable code from their own home directories, at least for now. b/112037137 covers further tightening we can do in this area. Bug: 112357170 Test: Device boots and no problems. Change-Id: Ia6a9eb4c2ed8a02ad45644d025181ba3c8424cda
229 lines
8.8 KiB
Text
229 lines
8.8 KiB
Text
###
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### A domain for further sandboxing privileged apps.
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###
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typeattribute priv_app coredomain;
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app_domain(priv_app)
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# Access the network.
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net_domain(priv_app)
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# Access bluetooth.
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bluetooth_domain(priv_app)
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# Allow the allocation and use of ptys
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# Used by: https://play.privileged.com/store/apps/details?id=jackpal.androidterm
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create_pty(priv_app)
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# webview crash handling depends on self ptrace (b/27697529, b/20150694, b/19277529#comment7)
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allow priv_app self:process ptrace;
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# Allow loading executable code from writable priv-app home
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# directories. This is a W^X violation, however, it needs
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# to be supported for now for the following reasons.
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# * /data/user_*/0/*/code_cache/* POSSIBLE uses (b/117841367)
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# 1) com.android.opengl.shaders_cache
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# 2) com.android.skia.shaders_cache
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# 3) com.android.renderscript.cache
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# * /data/user_de/0/com.google.android.gms/app_chimera
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# TODO: Tighten (b/112357170)
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allow priv_app privapp_data_file:file execute;
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allow priv_app app_api_service:service_manager find;
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allow priv_app audioserver_service:service_manager find;
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allow priv_app cameraserver_service:service_manager find;
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allow priv_app drmserver_service:service_manager find;
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allow priv_app mediacodec_service:service_manager find;
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allow priv_app mediadrmserver_service:service_manager find;
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allow priv_app mediaextractor_service:service_manager find;
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allow priv_app mediametrics_service:service_manager find;
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allow priv_app mediaserver_service:service_manager find;
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allow priv_app network_watchlist_service:service_manager find;
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allow priv_app nfc_service:service_manager find;
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allow priv_app oem_lock_service:service_manager find;
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allow priv_app persistent_data_block_service:service_manager find;
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allow priv_app radio_service:service_manager find;
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allow priv_app recovery_service:service_manager find;
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allow priv_app stats_service:service_manager find;
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allow priv_app system_api_service:service_manager find;
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# Write to /cache.
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allow priv_app { cache_file cache_recovery_file }:dir create_dir_perms;
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allow priv_app { cache_file cache_recovery_file }:file create_file_perms;
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# /cache is a symlink to /data/cache on some devices. Allow reading the link.
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allow priv_app cache_file:lnk_file r_file_perms;
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# Write to /data/ota_package for OTA packages.
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allow priv_app ota_package_file:dir rw_dir_perms;
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allow priv_app ota_package_file:file create_file_perms;
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# Access to /data/media.
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allow priv_app media_rw_data_file:dir create_dir_perms;
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allow priv_app media_rw_data_file:file create_file_perms;
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# Used by Finsky / Android "Verify Apps" functionality when
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# running "adb install foo.apk".
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allow priv_app shell_data_file:file r_file_perms;
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allow priv_app shell_data_file:dir r_dir_perms;
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# Allow traceur to pass file descriptors through a content provider to betterbug
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allow priv_app trace_data_file:file { getattr read };
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# Allow verifier to access staged apks.
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allow priv_app { apk_tmp_file apk_private_tmp_file }:dir r_dir_perms;
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allow priv_app { apk_tmp_file apk_private_tmp_file }:file r_file_perms;
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# b/18504118: Allow reads from /data/anr/traces.txt
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allow priv_app anr_data_file:file r_file_perms;
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# Allow GMS core to access perfprofd output, which is stored
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# in /data/misc/perfprofd/. GMS core will need to list all
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# data stored in that directory to process them one by one.
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userdebug_or_eng(`
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allow priv_app perfprofd_data_file:file r_file_perms;
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allow priv_app perfprofd_data_file:dir r_dir_perms;
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')
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# For AppFuse.
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allow priv_app vold:fd use;
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allow priv_app fuse_device:chr_file { read write };
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# /proc access
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allow priv_app {
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proc_vmstat
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}:file r_file_perms;
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allow priv_app sysfs_type:dir search;
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# Read access to /sys/class/net/wlan*/address
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r_dir_file(priv_app, sysfs_net)
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# Read access to /sys/block/zram*/mm_stat
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r_dir_file(priv_app, sysfs_zram)
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r_dir_file(priv_app, rootfs)
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# Allow GMS core to open kernel config for OTA matching through libvintf
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allow priv_app config_gz:file { open read getattr };
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# access the mac address
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allowxperm priv_app self:udp_socket ioctl SIOCGIFHWADDR;
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# Allow GMS core to communicate with update_engine for A/B update.
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binder_call(priv_app, update_engine)
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allow priv_app update_engine_service:service_manager find;
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# Allow GMS core to communicate with dumpsys storaged.
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binder_call(priv_app, storaged)
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allow priv_app storaged_service:service_manager find;
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# Allow GMS core to access system_update_service (e.g. to publish pending
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# system update info).
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allow priv_app system_update_service:service_manager find;
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# Allow GMS core to communicate with statsd.
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binder_call(priv_app, statsd)
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# Allow Phone to read/write cached ringtones (opened by system).
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allow priv_app ringtone_file:file { getattr read write };
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# Access to /data/preloads
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allow priv_app preloads_data_file:file r_file_perms;
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allow priv_app preloads_data_file:dir r_dir_perms;
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allow priv_app preloads_media_file:file r_file_perms;
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allow priv_app preloads_media_file:dir r_dir_perms;
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# Allow privileged apps (e.g. GMS core) to generate unique hardware IDs
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allow priv_app keystore:keystore_key gen_unique_id;
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# Allow GMS core to access /sys/fs/selinux/policyvers for compatibility check
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allow priv_app selinuxfs:file r_file_perms;
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read_runtime_log_tags(priv_app)
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# Write app-specific trace data to the Perfetto traced damon. This requires
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# connecting to its producer socket and obtaining a (per-process) tmpfs fd.
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allow priv_app traced:fd use;
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allow priv_app traced_tmpfs:file { read write getattr map };
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unix_socket_connect(priv_app, traced_producer, traced)
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# suppress denials for non-API accesses.
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dontaudit priv_app exec_type:file getattr;
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dontaudit priv_app device:dir read;
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dontaudit priv_app fs_bpf:dir search;
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dontaudit priv_app net_dns_prop:file read;
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dontaudit priv_app proc:file read;
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dontaudit priv_app proc_interrupts:file read;
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dontaudit priv_app proc_modules:file read;
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dontaudit priv_app proc_stat:file read;
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dontaudit priv_app proc_version:file read;
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dontaudit priv_app sysfs:dir read;
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dontaudit priv_app sysfs:file read;
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dontaudit priv_app sysfs_android_usb:file read;
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dontaudit priv_app wifi_prop:file read;
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dontaudit priv_app { wifi_prop exported_wifi_prop }:file read;
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# allow privileged apps to use UDP sockets provided by the system server but not
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# modify them other than to connect
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allow priv_app system_server:udp_socket {
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connect getattr read recvfrom sendto write getopt setopt };
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# Attempts to write to system_data_file is generally a sign
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# that apps are attempting to access encrypted storage before
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# the ACTION_USER_UNLOCKED intent is delivered. Suppress this
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# denial to prevent apps from spamming the logs.
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dontaudit priv_app system_data_file:dir write;
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###
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### neverallow rules
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###
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# Receive or send uevent messages.
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neverallow priv_app domain:netlink_kobject_uevent_socket *;
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# Receive or send generic netlink messages
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neverallow priv_app domain:netlink_socket *;
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# Too much leaky information in debugfs. It's a security
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# best practice to ensure these files aren't readable.
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neverallow priv_app debugfs:file read;
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# Do not allow privileged apps to register services.
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# Only trusted components of Android should be registering
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# services.
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neverallow priv_app service_manager_type:service_manager add;
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# Do not allow privileged apps to connect to the property service
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# or set properties. b/10243159
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neverallow priv_app property_socket:sock_file write;
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neverallow priv_app init:unix_stream_socket connectto;
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neverallow priv_app property_type:property_service set;
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# Do not allow priv_app to be assigned mlstrustedsubject.
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# This would undermine the per-user isolation model being
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# enforced via levelFrom=user in seapp_contexts and the mls
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# constraints. As there is no direct way to specify a neverallow
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# on attribute assignment, this relies on the fact that fork
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# permission only makes sense within a domain (hence should
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# never be granted to any other domain within mlstrustedsubject)
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# and priv_app is allowed fork permission to itself.
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neverallow priv_app mlstrustedsubject:process fork;
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# Do not allow priv_app to hard link to any files.
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# In particular, if priv_app links to other app data
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# files, installd will not be able to guarantee the deletion
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# of the linked to file. Hard links also contribute to security
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# bugs, so we want to ensure priv_app never has this
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# capability.
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neverallow priv_app file_type:file link;
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# priv apps should not be able to open trace data files, they should depend
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# upon traceur to pass a file descriptor which they can then read
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neverallow priv_app trace_data_file:dir *;
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neverallow priv_app trace_data_file:file { no_w_file_perms open };
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# Do not allow priv_app access to cgroups.
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neverallow priv_app cgroup:file *;
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# Do not allow loading executable code from non-privileged
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# application home directories. Code loading across a security boundary
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# is dangerous and allows a full compromise of a privileged process
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# by an unprivileged process. b/112357170
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neverallow priv_app app_data_file:file no_x_file_perms;
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