109 lines
5 KiB
Text
109 lines
5 KiB
Text
###
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### neverallow rules for untrusted app domains
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###
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# Only allow domains in AOSP to use the untrusted_app_all attribute.
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neverallow { untrusted_app_all -untrusted_app -untrusted_app_25 } domain:process fork;
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define(`all_untrusted_apps',`{ untrusted_app_all untrusted_app_25 untrusted_app ephemeral_app isolated_app mediaprovider }')
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# Receive or send uevent messages.
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neverallow all_untrusted_apps domain:netlink_kobject_uevent_socket *;
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# Receive or send generic netlink messages
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neverallow all_untrusted_apps 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 all_untrusted_apps debugfs_type:file read;
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# Do not allow untrusted 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 all_untrusted_apps service_manager_type:service_manager add;
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# Do not allow untrusted apps to connect to the property service
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# or set properties. b/10243159
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neverallow { all_untrusted_apps -mediaprovider } property_socket:sock_file write;
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neverallow { all_untrusted_apps -mediaprovider } init:unix_stream_socket connectto;
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neverallow { all_untrusted_apps -mediaprovider } property_type:property_service set;
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# Do not allow untrusted apps 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 an untrusted app is allowed fork permission to itself.
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neverallow all_untrusted_apps mlstrustedsubject:process fork;
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# Do not allow untrusted apps to hard link to any files.
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# In particular, if an untrusted 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 untrusted apps never have this
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# capability.
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neverallow all_untrusted_apps file_type:file link;
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# Do not allow untrusted apps to access network MAC address file
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neverallow all_untrusted_apps sysfs_mac_address:file no_rw_file_perms;
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# Restrict socket ioctls. Either 1. disallow privileged ioctls, 2. disallow the
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# ioctl permission, or 3. disallow the socket class.
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neverallowxperm all_untrusted_apps domain:{ rawip_socket tcp_socket udp_socket } ioctl priv_sock_ioctls;
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neverallow all_untrusted_apps *:{ netlink_route_socket netlink_selinux_socket } ioctl;
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neverallow all_untrusted_apps *:{
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socket netlink_socket packet_socket key_socket appletalk_socket
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netlink_tcpdiag_socket netlink_nflog_socket
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netlink_xfrm_socket netlink_audit_socket
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netlink_dnrt_socket netlink_kobject_uevent_socket tun_socket
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netlink_iscsi_socket netlink_fib_lookup_socket netlink_connector_socket
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netlink_netfilter_socket netlink_generic_socket netlink_scsitransport_socket
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netlink_rdma_socket netlink_crypto_socket
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} *;
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# Do not allow untrusted apps access to /cache
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neverallow { all_untrusted_apps -mediaprovider } { cache_file cache_recovery_file }:dir ~{ r_dir_perms };
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neverallow { all_untrusted_apps -mediaprovider } { cache_file cache_recovery_file }:file ~{ read getattr };
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# Do not allow untrusted apps to create/unlink files outside of its sandbox,
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# internal storage or sdcard.
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# World accessible data locations allow application to fill the device
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# with unaccounted for data. This data will not get removed during
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# application un-installation.
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neverallow { all_untrusted_apps -mediaprovider } {
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fs_type
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-fuse # sdcard
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-sdcardfs # sdcard
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-vfat
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file_type
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-app_data_file # The apps sandbox itself
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-media_rw_data_file # Internal storage. Known that apps can
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# leave artfacts here after uninstall.
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-user_profile_data_file # Access to profile files
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userdebug_or_eng(`
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-method_trace_data_file # only on ro.debuggable=1
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-coredump_file # userdebug/eng only
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')
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}:dir_file_class_set { create unlink };
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# Do not allow untrusted apps to directly open tun_device
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neverallow all_untrusted_apps tun_device:chr_file open;
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# Only allow appending to /data/anr/traces.txt (b/27853304, b/18340553)
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neverallow all_untrusted_apps anr_data_file:file ~{ open append };
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neverallow all_untrusted_apps anr_data_file:dir ~search;
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# Avoid reads from generically labeled /proc files
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# Create a more specific label if needed
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neverallow all_untrusted_apps proc:file { no_rw_file_perms no_x_file_perms };
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# Avoid all access to kernel configuration
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neverallow all_untrusted_apps config_gz:file { no_rw_file_perms no_x_file_perms };
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# Do not allow untrusted apps access to preloads data files
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neverallow all_untrusted_apps preloads_data_file:file no_rw_file_perms;
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# Locking of files on /system could lead to denial of service attacks
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# against privileged system components
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neverallow all_untrusted_apps system_file:file lock;
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