platform_system_sepolicy/public/logd.te
Nick Kralevich 5e37271df8 Introduce system_file_type
system_file_type is a new attribute used to identify files which exist
on the /system partition. It's useful for allow rules in init, which are
based off of a blacklist of writable files. Additionally, it's useful
for constructing neverallow rules to prevent regressions.

Additionally, add commented out tests which enforce that all files on
the /system partition have the system_file_type attribute. These tests
will be uncommented in a future change after all the device-specific
policies are cleaned up.

Test: Device boots and no obvious problems.
Change-Id: Id9bae6625f042594c8eba74ca712abb09702c1e5
2018-09-27 12:52:09 -07:00

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2.3 KiB
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# android user-space log manager
type logd, domain, mlstrustedsubject;
type logd_exec, system_file_type, exec_type, file_type;
# Read access to pseudo filesystems.
r_dir_file(logd, cgroup)
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 w_file_perms;
allow logd system_data_file:{ file lnk_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;
# Access device logging gating property
get_prop(logd, device_logging_prop)
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 { open read };
###
### 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:dir_file_class_set write;
# Write to files in /data/data or system files on /data
neverallow logd { app_data_file privapp_data_file system_data_file }: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;