Due to the sensitive nature of these fixes, it was not possible to
submit these upstream and vendor the upstream library. Instead, this
patch uses a fork of github.com/opencontainers/selinux, branched at
commit opencontainers/selinux@879a755db5.
In order to permit downstreams to build with this patched version, a
snapshot of the forked version has been included in
internal/third_party/selinux. Note that since we use "go mod vendor",
the patched code is usable even without being "go get"-able. Once the
embargo for this issue is lifted we can submit the patches upstream and
switch back to a proper upstream go.mod entry.
Also, this requires us to temporarily disable the CI job we have that
disallows "replace" directives.
Fixes: GHSA-cgrx-mc8f-2prm CVE-2025-52881
Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>