How to set SELinux enforcing, config file not found?
Yes, permissive SELinux could be one of the reasons of failed SafetyNET test (1). So you need to set it enforcing. However Android uses a modified version of libselinux, not dependent on /etc/selinux/config (2). On Android SELinux is configured when building ROM, and enforced by init when booting ROM. However if you have root, you can use setenforce command (located under /system/bin) or write directly to Kernel Configuration File (/sys/fs/selinux/enforce). But make sure you have a working SE policy before enforcing, or you may get stuck.