Add sysprop for init's perf_event_open LSM hook check
Written exclusively by init. Made it readable by shell for CTS, and for
easier platform debugging.
Bug: 137092007
Change-Id: Ia5b056117502c272bc7169661069d0c8020695e2
diff --git a/private/init.te b/private/init.te
index 116eff4..42ec0f3 100644
--- a/private/init.te
+++ b/private/init.te
@@ -45,3 +45,18 @@
set_prop(init, userspace_reboot_exported_prop)
neverallow { domain -init } userspace_reboot_prop:property_service set;
neverallow { domain -init } userspace_reboot_exported_prop:property_service set;
+
+# Second-stage init performs a test for whether the kernel has SELinux hooks
+# for the perf_event_open() syscall. This is done by testing for the syscall
+# outcomes corresponding to this policy.
+# TODO(b/137092007): this can be removed once the platform stops supporting
+# kernels that precede the perf_event_open hooks (Android common kernels 4.4
+# and 4.9).
+allow init self:perf_event { open cpu };
+neverallow init self:perf_event { kernel tracepoint read write };
+dontaudit init self:perf_event { kernel tracepoint read write };
+
+# Only init is allowed to set the sysprop indicating whether perf_event_open()
+# SELinux hooks were detected.
+set_prop(init, init_perf_lsm_hooks_prop)
+neverallow { domain -init } init_perf_lsm_hooks_prop:property_service set;