platform_system_sepolicy/public/lmkd.te
Marco Ballesio f46d7a26c1 sepolicy: rules for uid/pid cgroups v2 hierarchy
the cgroups v2 uid/gid hierarchy will replace cgroup for all sepolicy
rules. For this reason, old rules have to be duplicated to cgroup_v2,
plus some rules must be added to allow the ownership change for cgroup
files created by init and zygote.

Test: booted device, verified correct access from init, system_server
and zygote to the uid/pid cgroup files

Change-Id: I80c2a069b0fb409b442e1160148ddc48e31d6809
2020-11-30 11:46:14 -08:00

72 lines
2.3 KiB
Text

# lmkd low memory killer daemon
type lmkd, domain, mlstrustedsubject;
type lmkd_exec, system_file_type, exec_type, file_type;
allow lmkd self:global_capability_class_set { dac_override dac_read_search sys_resource kill };
# lmkd locks itself in memory, to prevent it from being
# swapped out and unable to kill other memory hogs.
# system/core commit b28ff9131363f7b4a698990da5748b2a88c3ed35
# b/16236289
allow lmkd self:global_capability_class_set ipc_lock;
## Open and write to /proc/PID/oom_score_adj and /proc/PID/timerslack_ns
## TODO: maybe scope this down?
r_dir_file(lmkd, domain)
allow lmkd domain:file write;
## Writes to /sys/module/lowmemorykiller/parameters/minfree
r_dir_file(lmkd, sysfs_lowmemorykiller)
allow lmkd sysfs_lowmemorykiller:file w_file_perms;
# setsched and send kill signals to any registered process
allow lmkd domain:process { setsched sigkill };
# TODO: delete this line b/131761776
allow lmkd kernel:process { setsched };
# Clean up old cgroups
allow lmkd cgroup:dir { remove_name rmdir };
allow lmkd cgroup_v2:dir { remove_name rmdir };
# Allow to read memcg stats
allow lmkd cgroup:file r_file_perms;
allow lmkd cgroup_v2:file r_file_perms;
# Set self to SCHED_FIFO
allow lmkd self:global_capability_class_set sys_nice;
allow lmkd proc_zoneinfo:file r_file_perms;
allow lmkd proc_vmstat:file r_file_perms;
# live lock watchdog process allowed to look through /proc/
allow lmkd domain:dir { search open read };
allow lmkd domain:file { open read };
# live lock watchdog process allowed to dump process trace and
# reboot because orderly shutdown may not be possible.
allow lmkd proc_sysrq:file rw_file_perms;
# Read /proc/lowmemorykiller
allow lmkd proc_lowmemorykiller:file r_file_perms;
# Read /proc/meminfo
allow lmkd proc_meminfo:file r_file_perms;
# Read /proc/pressure/cpu and /proc/pressure/io
allow lmkd proc_pressure_cpu:file r_file_perms;
allow lmkd proc_pressure_io:file r_file_perms;
# Read/Write /proc/pressure/memory
allow lmkd proc_pressure_mem:file rw_file_perms;
# Allow lmkd to connect during reinit.
allow lmkd lmkd_socket:sock_file write;
# Allow lmkd to write to statsd.
unix_socket_send(lmkd, statsdw, statsd)
### neverallow rules
# never honor LD_PRELOAD
neverallow * lmkd:process noatsecure;
neverallow lmkd self:global_capability_class_set sys_ptrace;