Deploying an OSTree commit leads to creation of hardlinks from
the repository to the check out. These will have the correct
SELinux labels, since the files in the repository will have the
correct SELinux labels[1]. But new files are generated in '/etc'
of the new deployment, due to the 3-way configuration merge[2].
Also a new kernel, initramfs and the corresponding Bootloader
Specification entries are created in the global '/boot' dir.
In theory, ostree will set the correct SELinux labels by loading
the SELinux config from the deployment and then setting the
correct security contexts via ostree_sepolicy_setfscreatecon().
But it does so conditionally on is_selinux_enabled(2)[3], which
in our container is FALSE Therefore we have to do the same dance
as ostree does, at least for now, and manually re-label the
affected paths.
[1] Assuming they had the correct label when the commit was made
[2] https://ostree.readthedocs.io/en/latest/manual/deployment/
[3] via ostree_sepolicy_setfscreatecon in ostree-sepolicy.c
line 640 of commit 2c1658538f8fde5813e95e7408d65662a489be91
fd5efd0d29