platform_system_sepolicy/private/logd.te

typeattribute logd coredomain;

init_daemon_domain(logd)

# Access device logging gating property
get_prop(logd, device_logging_prop)

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

# protect the event-log-tags file
neverallow {
  domain
  -appdomain # covered below
  -bootstat
  -dumpstate
  -init
  -logd
  userdebug_or_eng(`-logpersist')
  -servicemanager
  -system_server
  -surfaceflinger
  -zygote
} runtime_event_log_tags_file:file no_rw_file_perms;

neverallow {
  appdomain
  -bluetooth
  -platform_app
  -priv_app
  -radio
  -shell
  userdebug_or_eng(`-su')
  -system_app
} runtime_event_log_tags_file:file no_rw_file_perms;

# Only binder communication between logd and system_server is allowed
binder_use(logd)
binder_service(logd)
binder_call(logd, system_server)

add_service(logd, logd_service)
allow logd logcat_service:service_manager find;

# Read access to pseudo filesystems.
r_dir_file(logd, cgroup)
r_dir_file(logd, cgroup_v2)
r_dir_file(logd, proc_kmsg)
r_dir_file(logd, proc_meminfo)

allow logd self:global_capability_class_set { setuid setgid setpcap sys_nice audit_control };
allow logd self:global_capability2_class_set 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 { getattr w_file_perms };
allow logd system_data_file:{ file lnk_file } r_file_perms;
allow logd packages_list_file:file r_file_perms;
allow logd pstorefs:dir search;
allow logd pstorefs:file r_file_perms;
userdebug_or_eng(`
  # Access to /data/misc/logd/event-log-tags
  allow logd misc_logd_file:dir r_dir_perms;
  allow logd misc_logd_file:file rw_file_perms;
')
allow logd runtime_event_log_tags_file:file rw_file_perms;

r_dir_file(logd, domain)

allow logd kernel:system syslog_mod;

control_logd(logd)
read_runtime_log_tags(logd)

allow runtime_event_log_tags_file tmpfs:filesystem associate;
# Typically harmlessly blindly trying to access via liblog
# event tag mapping while in the untrusted_app domain.
# Access for that domain is controlled and gated via the
# event log tag service (albeit at a performance penalty,
# expected to be locally cached).
dontaudit domain runtime_event_log_tags_file:file { map open read };

# Logd sets defaults if certain properties are empty.
set_prop(logd, logd_prop)

###
### 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;

# ... and nobody may ptrace me (except on userdebug or eng builds)
neverallow { domain userdebug_or_eng(`-crash_dump -llkd') } logd:process ptrace;

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

# Write to files in /data/data or system files on /data
neverallow logd {
    app_data_file_type
    system_data_file
    packages_list_file
    -shell_data_file # for bugreports
}:dir_file_class_set write;

# Only init is allowed to enter the logd domain via exec()
neverallow { domain -init } logd:process transition;
neverallow * logd:process dyntransition;

# protect the event-log-tags file
neverallow {
  domain
  -init
  -logd
} runtime_event_log_tags_file:file no_w_file_perms;