Add microdroid specific sepolicy
Microdroid will have a separate sepolicy, apart from the core policy.
This is the first step; For now it's a simple copy of system/sepolicy.
For the future work, it will be stripped.
Bug: 189165759
Test: boot microdroid and see selinux enforced
Change-Id: I2fee39f7231560b49c93bd5e8d0feeffada40938
diff --git a/microdroid/sepolicy/system/private/mls b/microdroid/sepolicy/system/private/mls
new file mode 100644
index 0000000..955c27b
--- /dev/null
+++ b/microdroid/sepolicy/system/private/mls
@@ -0,0 +1,116 @@
+#################################################
+# MLS policy constraints
+#
+
+#
+# Process constraints
+#
+
+# Process transition: Require equivalence unless the subject is trusted.
+mlsconstrain process { transition dyntransition }
+ ((h1 eq h2 and l1 eq l2) or t1 == mlstrustedsubject);
+
+# Process read operations: No read up unless trusted.
+mlsconstrain process { getsched getsession getpgid getcap getattr ptrace share }
+ (l1 dom l2 or t1 == mlstrustedsubject);
+
+# Process write operations: Require equivalence unless trusted.
+mlsconstrain process { sigkill sigstop signal setsched setpgid setcap setrlimit ptrace share }
+ (l1 eq l2 or t1 == mlstrustedsubject);
+
+#
+# Socket constraints
+#
+
+# Create/relabel operations: Subject must be equivalent to object unless
+# the subject is trusted. Sockets inherit the range of their creator.
+mlsconstrain socket_class_set { create relabelfrom relabelto }
+ ((h1 eq h2 and l1 eq l2) or t1 == mlstrustedsubject);
+
+# Datagram send: Sender must be equivalent to the receiver unless one of them
+# is trusted.
+mlsconstrain unix_dgram_socket { sendto }
+ (l1 eq l2 or t1 == mlstrustedsubject or t2 == mlstrustedsubject);
+
+# Stream connect: Client must be equivalent to server unless one of them
+# is trusted.
+mlsconstrain unix_stream_socket { connectto }
+ (l1 eq l2 or t1 == mlstrustedsubject or t2 == mlstrustedsubject);
+
+#
+# Directory/file constraints
+#
+
+# Create/relabel operations: Subject must be equivalent to object unless
+# the subject is trusted. Also, files should always be single-level.
+# Do NOT exempt mlstrustedobject types from this constraint.
+mlsconstrain dir_file_class_set { create relabelfrom relabelto }
+ (l2 eq h2 and (l1 eq l2 or t1 == mlstrustedsubject));
+
+#
+# Userfaultfd constraints
+#
+# To enforce that anonymous inodes are self contained in the application's process.
+mlsconstrain anon_inode { ioctl read write create getattr setattr lock relabelfrom relabelto append map unlink link rename execute open execmod }
+ (l1 eq l2);
+
+#
+# Constraints for app data files only.
+#
+
+# Only constrain open, not read/write, so already open fds can be used.
+# Also constrain other forms of manipulation, e.g. chmod/chown, unlink, rename, etc.
+# Subject must dominate object unless the subject is trusted.
+mlsconstrain dir { open search getattr setattr rename add_name remove_name reparent rmdir }
+ (t2 != app_data_file_type or l1 dom l2 or t1 == mlstrustedsubject);
+mlsconstrain { file sock_file } { open setattr unlink link rename }
+ ( (t2 != app_data_file_type and t2 != appdomain_tmpfs) or l1 dom l2 or t1 == mlstrustedsubject);
+
+# For symlinks in app data files, require equivalence in order to manipulate or follow (read).
+mlsconstrain { lnk_file } { open setattr unlink link rename read }
+ ( (t2 != app_data_file_type or t2 == privapp_data_file) or l1 eq l2 or t1 == mlstrustedsubject);
+# But for priv_app_data_file, continue to use dominance for symlinks because dynamite relies on this.
+# TODO: Migrate to equivalence when it's no longer needed.
+mlsconstrain { lnk_file } { open setattr unlink link rename read }
+ ( (t2 != privapp_data_file and t2 != appdomain_tmpfs) or l1 dom l2 or t1 == mlstrustedsubject);
+
+#
+# Constraints for file types other than app data files.
+#
+
+# Read operations: Subject must dominate object unless the subject
+# or the object is trusted.
+mlsconstrain dir { read getattr search }
+ (t2 == app_data_file_type or l1 dom l2 or t1 == mlstrustedsubject or t2 == mlstrustedobject
+ or (t1 == mlsvendorcompat and (t2 == system_data_file or t2 == user_profile_root_file) ) );
+
+mlsconstrain { file lnk_file sock_file chr_file blk_file } { read getattr execute }
+ (t2 == app_data_file_type or t2 == appdomain_tmpfs or l1 dom l2 or t1 == mlstrustedsubject or t2 == mlstrustedobject);
+
+# Write operations: Subject must be equivalent to the object unless the
+# subject or the object is trusted.
+mlsconstrain dir { write setattr rename add_name remove_name reparent rmdir }
+ (t2 == app_data_file_type or l1 eq l2 or t1 == mlstrustedsubject or t2 == mlstrustedobject);
+
+mlsconstrain { file lnk_file sock_file chr_file blk_file } { write setattr append unlink link rename }
+ (t2 == app_data_file_type or t2 == appdomain_tmpfs or l1 eq l2 or t1 == mlstrustedsubject or t2 == mlstrustedobject);
+
+# Special case for FIFOs.
+# These can be unnamed pipes, in which case they will be labeled with the
+# creating process' label. Thus we also have an exemption when the "object"
+# is a domain type, so that processes can communicate via unnamed pipes
+# passed by binder or local socket IPC.
+mlsconstrain fifo_file { read getattr }
+ (l1 dom l2 or t1 == mlstrustedsubject or t2 == mlstrustedobject or t2 == domain);
+
+mlsconstrain fifo_file { write setattr append unlink link rename }
+ (l1 eq l2 or t1 == mlstrustedsubject or t2 == mlstrustedobject or t2 == domain);
+
+#
+# Binder IPC constraints
+#
+# Presently commented out, as apps are expected to call one another.
+# This would only make sense if apps were assigned categories
+# based on allowable communications rather than per-app categories.
+#mlsconstrain binder call
+# (l1 eq l2 or t1 == mlstrustedsubject or t2 == mlstrustedsubject);