platform_system_sepolicy/public/logd.te

# android user-space log manager
type logd, domain, mlstrustedsubject;
type logd_exec, exec_type, file_type;

# Read access to pseudo filesystems.
r_dir_file(logd, cgroup)
r_dir_file(logd, proc)
r_dir_file(logd, proc_meminfo)
r_dir_file(logd, proc_net)

allow logd self:capability { setuid setgid setpcap sys_nice audit_control };
allow logd self:capability2 syslog;
allow logd self:netlink_audit_socket { create_socket_perms_no_ioctl nlmsg_write };
allow logd kernel:system syslog_read;
allow logd kmsg_device:chr_file w_file_perms;
allow logd system_data_file:{ file lnk_file } r_file_perms;
# logpersist is only allowed on userdebug and eng builds
userdebug_or_eng(`
  allow logd misc_logd_file:file create_file_perms;
  allow logd misc_logd_file:dir rw_dir_perms;
')
allow logd pstorefs:dir search;
allow logd pstorefs:file r_file_perms;

# Set persist.sys. and sys.powerctl
set_prop(logd, safemode_prop)
set_prop(logd, powerctl_prop)

# Access device logging gating property
get_prop(logd, device_logging_prop)
userdebug_or_eng(`get_prop(logd, logpersistd_logging_prop)')

r_dir_file(logd, domain)

allow logd kernel:system syslog_mod;

control_logd(logd)

# case where logpersistd is actually logcat -f in logd context (nee: logcatd)
userdebug_or_eng(`
  unix_socket_connect(logd, logdr, logd)
')

###
### Neverallow rules
###
### logd should NEVER do any of this

# Block device access.
neverallow logd dev_type:blk_file { read write };

# ptrace any other app
neverallow logd domain:process ptrace;

# Write to /system.
neverallow logd system_file:dir_file_class_set write;

# Write to files in /data/data or system files on /data
neverallow logd { app_data_file system_data_file }:dir_file_class_set write;

# logd is not allowed to write anywhere other than /data/misc/logd, and then
# only on userdebug or eng builds
neverallow logd { file_type -logd_tmpfs userdebug_or_eng(` -misc_logd_file -coredump_file ') }:file { create write append };

# logpersist is only allowed on userdebug/eng builds
neverallow { domain userdebug_or_eng(`-logd -shell -dumpstate') } misc_logd_file:file no_rw_file_perms;
neverallow { domain userdebug_or_eng(`-logd') } misc_logd_file:dir { add_name link relabelfrom remove_name rename reparent rmdir write };
neverallow { domain -init } misc_logd_file:dir create;