1# lmkd low memory killer daemon
2type lmkd, domain, mlstrustedsubject;
3type lmkd_exec, exec_type, file_type;
4
5allow lmkd self:global_capability_class_set { dac_override sys_resource kill };
6
7# lmkd locks itself in memory, to prevent it from being
8# swapped out and unable to kill other memory hogs.
9# system/core commit b28ff9131363f7b4a698990da5748b2a88c3ed35
10# b/16236289
11allow lmkd self:global_capability_class_set ipc_lock;
12
13## Open and write to /proc/PID/oom_score_adj
14## TODO: maybe scope this down?
15r_dir_file(lmkd, appdomain)
16allow lmkd appdomain:file write;
17r_dir_file(lmkd, system_server)
18allow lmkd system_server:file write;
19
20## Writes to /sys/module/lowmemorykiller/parameters/minfree
21r_dir_file(lmkd, sysfs_lowmemorykiller)
22allow lmkd sysfs_lowmemorykiller:file w_file_perms;
23
24# setsched and send kill signals
25allow lmkd appdomain:process { setsched sigkill };
26
27# Clean up old cgroups
28allow lmkd cgroup:dir { remove_name rmdir };
29
30# Allow to read memcg stats
31allow lmkd cgroup:file r_file_perms;
32
33# Set self to SCHED_FIFO
34allow lmkd self:global_capability_class_set sys_nice;
35
36allow lmkd proc_zoneinfo:file r_file_perms;
37
38# live lock watchdog process allowed to look through /proc/
39allow lmkd domain:dir { search open read };
40allow lmkd domain:file { open read };
41
42# live lock watchdog process allowed to dump process trace and
43# reboot because orderly shutdown may not be possible.
44allow lmkd proc_sysrq:file rw_file_perms;
45
46# Read /proc/meminfo
47allow lmkd proc_meminfo:file r_file_perms;
48
49### neverallow rules
50
51# never honor LD_PRELOAD
52neverallow * lmkd:process noatsecure;
53