topjohnwu e841aab9e7 Add hijack sepolicy support for rootfs devices
On older Android versions, pre-mounting selinuxfs will lead to errors,
so we have to use a different method to block init's control flow.
Since all devices that falls in this catagory must both:

1. Be Android 8.0 - 9.0
2. Have early mount fstab in its device tree

We can actually use the same FIFO trick, but this time not on selinuxfs,
but on the read-only device tree nodes in sysfs or procfs. By mocking
the fstab/compatible node in the device tree, we can block init when
it attempts to do early mount; at that point, we can then mock selinuxfs
as we normally would, successfully hijack and inject patched sepolicy.
2022-03-16 20:01:28 -07:00
..
2022-03-14 04:22:09 -07:00