platform_system_sepolicy/private/lmkd.te

typeattribute lmkd coredomain;
typeattribute lmkd bpfdomain;

init_daemon_domain(lmkd)

# Set sys.lmk.* properties.
set_prop(lmkd, system_lmk_prop)

# Set lmkd.* properties.
set_prop(lmkd, lmkd_prop)

# Get persist.device_config.lmk_native.* properties.
get_prop(lmkd, device_config_lmkd_native_prop)

# Needed for reading tracepoint ids in order to attach bpf programs.
allow lmkd debugfs_tracing:file r_file_perms;
allow lmkd self:perf_event { cpu kernel open write };

allow lmkd fs_bpf:file read;
allow lmkd bpfloader:bpf { map_read map_write prog_run };

# Needed for polling directly from the bpf ring buffer's fd
allow lmkd fs_bpf_lmkd_memevents_rb:file { read write };
allow lmkd fs_bpf_lmkd_memevents_prog:file read;

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;
neverallow { domain -init -lmkd -vendor_init } lmkd_prop:property_service set;
neverallow lmkd self:perf_event ~{ cpu kernel open write };