57f1b89db6
https://android-review.googlesource.com/94851 added an LD_PRELOAD
line to init.environ.rc.in. This has the effect of loading
libsigchain.so into every process' memory space, regardless of
whether it wants it or not.
For lmkd, it doesn't need libsigchain, so it doesn't make any sense
to load it and keep it locked in memory.
Disable noatsecure for lmkd. This sets AT_SECURE=1, which instructs the
linker to not honor security sensitive environment variables such
as LD_PRELOAD. This prevents libsigchain.so from being loaded into
lmkd's memory.
(cherry picked from commit 8a5b28d259)
Change-Id: I39baaf62058986d35ad43de708aaa3daf93b2df4
37 lines
1,003 B
Text
37 lines
1,003 B
Text
# lmkd low memory killer daemon
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type lmkd, domain;
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type lmkd_exec, exec_type, file_type;
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init_daemon_domain(lmkd)
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allow lmkd self:capability { dac_override sys_resource kill };
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# lmkd locks itself in memory, to prevent it from being
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# swapped out and unable to kill other memory hogs.
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# system/core commit b28ff9131363f7b4a698990da5748b2a88c3ed35
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# b/16236289
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allow lmkd self:capability ipc_lock;
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## Open and write to /proc/PID/oom_score_adj
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## TODO: maybe scope this down?
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r_dir_file(lmkd, appdomain)
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allow lmkd appdomain:file write;
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r_dir_file(lmkd, system_server)
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allow lmkd system_server:file write;
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## Writes to /sys/module/lowmemorykiller/parameters/minfree
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allow lmkd sysfs_lowmemorykiller:file w_file_perms;
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# Send kill signals
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allow lmkd appdomain:process sigkill;
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# Clean up old cgroups
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allow lmkd cgroup:dir { remove_name rmdir };
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# Set self to SCHED_FIFO
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allow lmkd self:capability sys_nice;
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### neverallow rules
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# never honor LD_PRELOAD
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neverallow domain lmkd:process noatsecure;
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