android_system_sepolicy/public/update_engine.te
Benjamin Gordon 9b2e0cbeea sepolicy: Add rules for non-init namespaces
In kernel 4.7, the capability and capability2 classes were split apart
from cap_userns and cap2_userns (see kernel commit
8e4ff6f228e4722cac74db716e308d1da33d744f). Since then, Android cannot be
run in a container with SELinux in enforcing mode.

This change applies the existing capability rules to user namespaces as
well as the root namespace so that Android running in a container
behaves the same on pre- and post-4.7 kernels.

This is essentially:
  1. New global_capability_class_set and global_capability2_class_set
     that match capability+cap_userns and capability2+cap2_userns,
     respectively.
  2. s/self:capability/self:global_capability_class_set/g
  3. s/self:capability2/self:global_capability2_class_set/g
  4. Add cap_userns and cap2_userns to the existing capability_class_set
     so that it covers all capabilities.  This set was used by several
     neverallow and dontaudit rules, and I confirmed that the new
     classes are still appropriate.

Test: diff new policy against old and confirm that all new rules add
      only cap_userns or cap2_userns;
      Boot ARC++ on a device with the 4.12 kernel.
Bug: crbug.com/754831

Change-Id: I4007eb3a2ecd01b062c4c78d9afee71c530df95f
2017-11-21 08:34:32 -07:00

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# Domain for update_engine daemon.
type update_engine, domain, update_engine_common;
type update_engine_exec, exec_type, file_type;
net_domain(update_engine);
# Read/[write] to /proc/net/xt_qtaguid/ctrl and /dev/xt_qtaguid to tag network
# sockets.
allow update_engine qtaguid_proc:file rw_file_perms;
allow update_engine qtaguid_device:chr_file r_file_perms;
# Following permissions are needed for update_engine.
allow update_engine self:process { setsched };
allow update_engine self:global_capability_class_set { fowner sys_admin };
# Note: fsetid checks are triggered when creating a file in a directory with
# the setgid bit set to determine if the file should inherit setgid. In this
# case, setgid on the file is undesirable so we should just suppress the
# denial.
dontaudit update_engine self:global_capability_class_set fsetid;
allow update_engine kmsg_device:chr_file w_file_perms;
allow update_engine update_engine_exec:file rx_file_perms;
wakelock_use(update_engine);
# Ignore these denials.
dontaudit update_engine kernel:process setsched;
# Allow using persistent storage in /data/misc/update_engine.
allow update_engine update_engine_data_file:dir create_dir_perms;
allow update_engine update_engine_data_file:file create_file_perms;
# Allow using persistent storage in /data/misc/update_engine_log.
allow update_engine update_engine_log_data_file:dir create_dir_perms;
allow update_engine update_engine_log_data_file:file create_file_perms;
# Don't allow kernel module loading, just silence the logs.
dontaudit update_engine kernel:system module_request;
# Register the service to perform Binder IPC.
binder_use(update_engine)
add_service(update_engine, update_engine_service)
# Allow update_engine to call the callback function provided by priv_app.
binder_call(update_engine, priv_app)
# Read OTA zip file at /data/ota_package/.
allow update_engine ota_package_file:file r_file_perms;
allow update_engine ota_package_file:dir r_dir_perms;
# Use Boot Control HAL
hal_client_domain(update_engine, hal_bootctl)
# access /proc/misc
allow update_engine proc_misc:file r_file_perms;
# read directories on /system and /vendor
allow update_engine system_file:dir r_dir_perms;