private/traced.te

# Perfetto user-space tracing daemon (unprivileged)

# type traced is defined under /public (because iorapd rules
# under public/ need to refer to it).
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 };

# Allow traceur to pass open file descriptors to traced, so traced can directly
# write into the output file without doing roundtrips over IPC.
allow traced traceur_app:fd use;
allow traced trace_data_file:file { read write };

# Allow iorapd to pass memfd descriptors to traced, so traced can directly
# write into the shmem buffer file without doing roundtrips over IPC.
allow traced iorapd:fd use;
allow traced iorapd_tmpfs: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
  -trace_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;