SEPolicy changes to allow kcov access in userdebug.

This includes the SELinux policy changes to allow for
kcov access in userdebug builds for coverage-guided
kernel fuzzing.

Bug: 117990869

Test: Ran syzkaller with Android untrusted_app sandbox with coverage.
Change-Id: I1fcaad447c7cdc2a3360383b5dcd76e8a0f93f09
diff --git a/private/untrusted_app_all.te b/private/untrusted_app_all.te
index 527216d..72e03e1 100644
--- a/private/untrusted_app_all.te
+++ b/private/untrusted_app_all.te
@@ -140,3 +140,10 @@
 # the ACTION_USER_UNLOCKED intent is delivered. Suppress this
 # denial to prevent third party apps from spamming the logs.
 dontaudit untrusted_app_all system_data_file:dir write;
+
+# Allow access to kcov via its ioctl interface for coverage
+# guided kernel fuzzing.
+userdebug_or_eng(`
+  allow untrusted_app_all debugfs_kcov:file rw_file_perms;
+  allowxperm untrusted_app_all debugfs_kcov:file ioctl { KCOV_INIT_TRACE KCOV_ENABLE KCOV_DISABLE };
+')