platform_system_sepolicy/microdroid/system/private/traced.te
Nikita Ioffe 6069e7c8f2 Add selinux rules for perfetto daemones
Note: this is a somewhat minimal set of rules required to be able to
capture traces on Microdroid. After the trace is captured I still see a
bunch of SELinux denials. We might need to add more allow rules in the
follow up changes.

Bug: 249050813
Test: boot Microdroid VM, capture traces with record_android_traces
Change-Id: I62098fb79a8db65706a5bb28c8acce7ff3821f15
2023-03-14 15:07:54 +00:00

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# SELinux policy for the traced daemon running inside Microdroid.
# For the host Android policy check system/sepolicy/private/traced.te
# So far, this is file contains a subset of rules defined for the host Android.
type traced, domain, coredomain;
type traced_exec, system_file_type, exec_type, file_type;
type traced_tmpfs, file_type;
# Allow init to exec traced daemon
init_daemon_domain(traced)
# Required for perfetto_produced macro
tmpfs_domain(traced)
# 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 shell:fifo_file { read write };
# Allow the service to create new files within /data/misc/perfetto-traces.
allow traced perfetto_traces_data_file:file create_file_perms;
allow traced perfetto_traces_data_file:dir rw_dir_perms;
# Allow traced to use shared memory supplied by producers. Typically, traced
# (i.e. the tracing service) creates the shared memory used for data transfer
# from the producer. This rule allows an alternative scheme, where the producer
# creates the shared memory, that is then adopted by traced (after validating
# that it is appropriately sealed).
# This list has to replicate the tmpfs domains of all applicable domains that
# have perfetto_producer() macro applied to them.
# perfetto_tmpfs excluded as it should never need to use the producer-supplied
# shared memory scheme.
allow traced traced_probes_tmpfs:file { getattr map read write };
###
### Neverallow rules
###
### traced should NEVER do any of this
# 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
-perfetto_traces_data_file
# We need following 3 lines because allow rules for them are defined at the
# domain/coredomain level.
-system_data_file
-system_data_root_file
-vendor_data_file
}:dir *;
neverallow traced system_data_file:dir ~{ getattr search };
neverallow traced {
data_file_type
-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;