Sepolicy: Initial Apexd pre-/postinstall rules

Give apexd permission to execute sh.

Add userdebug_or_eng domains and rules for the test
APEX for pre- and post-install.

Bug: 119260955
Bug: 119261380
Test: atest apexservice_test
Change-Id: I0c4a5e35e096101a53c9d1f212d2db2e63728267

apex/apex.test-file_contexts

@@ -1,2 +1,4 @@
-(/.*)?                 u:object_r:system_file:s0
+/bin/apex_test_preInstallHook  u:object_r:apex_test_prepostinstall_exec:s0
-/bin/surfaceflinger    u:object_r:surfaceflinger_exec:s0
+/bin/apex_test_postInstallHook u:object_r:apex_test_prepostinstall_exec:s0
+(/.*)?                         u:object_r:system_file:s0
+/bin/surfaceflinger            u:object_r:surfaceflinger_exec:s0

private/apex_test_prepostinstall.te

@@ -0,0 +1,20 @@
+# APEX pre- & post-install test.
+#
+# Allow to run pre- and post-install hooks for APEX test modules
+# in debuggable builds.
+
+type apex_test_prepostinstall, domain, coredomain;
+type apex_test_prepostinstall_exec, system_file_type, exec_type, file_type;
+
+userdebug_or_eng(`
+  # /dev/zero
+  allow apex_test_prepostinstall apexd:fd use;
+  # Logwrapper.
+  create_pty(apex_test_prepostinstall)
+  # Logwrapper executing sh.
+  allow apex_test_prepostinstall shell_exec:file rx_file_perms;
+  # Logwrapper exec.
+  allow apex_test_prepostinstall system_file:file execute_no_trans;
+  # Ls.
+  allow apex_test_prepostinstall toolbox_exec:file rx_file_perms;
+')

private/apexd.te

@@ -70,6 +70,20 @@ dontaudit apexd self:global_capability_class_set { dac_override dac_read_search
 # Allow apexd to log to the kernel.
 allow apexd kmsg_device:chr_file w_file_perms;
 
+# Apex pre- & post-install permission.
+
+# Allow self-execute for the fork mount helper.
+allow apexd apexd_exec:file execute_no_trans;
+
+# Allow to execute shell for pre- and postinstall scripts. A transition
+# rule is required, thus restricted to execute and not execute_no_trans.
+allow apexd shell_exec:file { r_file_perms execute };
+
+# Allow transition to test APEX preinstall domain.
+userdebug_or_eng(`
+  domain_auto_trans(apexd, apex_test_prepostinstall_exec, apex_test_prepostinstall)
+')
+
 neverallow { domain -apexd -init } apex_data_file:dir no_w_dir_perms;
 neverallow { domain -apexd -init -kernel } apex_data_file:file no_w_file_perms;
 neverallow { domain -apexd } apex_mnt_dir:lnk_file no_w_file_perms;