platform_system_sepolicy/private/traced.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

60 lines
2.1 KiB
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# Perfetto user-space tracing daemon (unprivileged)
type traced, domain, coredomain, mlstrustedsubject;
type traced_exec, system_file_type, exec_type, file_type;
# Allow init to exec the daemon.
init_daemon_domain(traced)
# Allow apps in other MLS contexts (for multi-user) to access
# share memory buffers created by traced.
typeattribute traced_tmpfs mlstrustedobject;
# Allow traced to start with a lower scheduling class and change
# class accordingly to what defined in the config provided by
# the privileged process that controls it.
allow traced self:global_capability_class_set { sys_nice };
# Allow to pass a file descriptor for the output trace from "perfetto" (the
# cmdline client) and other shell binaries to traced and let traced write
# directly into that (rather than returning the trace contents over the socket).
allow traced perfetto:fd use;
allow traced shell:fd use;
allow traced perfetto_traces_data_file:file { read write };
###
### Neverallow rules
###
### traced should NEVER do any of this
# Disallow mapping executable memory (execstack and exec are already disallowed
# globally in domain.te).
neverallow traced self:process execmem;
# Block device access.
neverallow traced dev_type:blk_file { read write };
# ptrace any other process
neverallow traced domain:process ptrace;
# Disallows access to /data files, still allowing to write to file descriptors
# passed through the socket.
neverallow traced {
data_file_type
-system_data_file
# TODO(b/72998741) Remove vendor_data_file exemption. Further restricted in a
# subsequent neverallow. Currently only getattr and search are allowed.
-vendor_data_file
-zoneinfo_data_file
}:dir *;
neverallow traced { system_data_file }:dir ~{ getattr search };
neverallow traced zoneinfo_data_file:dir ~r_dir_perms;
neverallow traced { data_file_type -zoneinfo_data_file }:lnk_file *;
neverallow traced {
data_file_type
-zoneinfo_data_file
-perfetto_traces_data_file
}:file ~write;
# Only init is allowed to enter the traced domain via exec()
neverallow { domain -init } traced:process transition;
neverallow * traced:process dyntransition;