Merge pull request #42334 from AkihiroSuda/rootless-overlay2-k511-selinux

rootless: disable overlay2 if running with SELinux
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Brian Goff 2021-06-03 10:33:27 -07:00 committed by GitHub
commit 20eb137e0a
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2 changed files with 23 additions and 0 deletions

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@ -84,6 +84,12 @@ if [ -z $_DOCKERD_ROOTLESS_CHILD ]; then
echo "This script must be executed as a non-privileged user"
exit 1
fi
# `selinuxenabled` always returns false in RootlessKit child, so we execute `selinuxenabled` in the parent.
# https://github.com/rootless-containers/rootlesskit/issues/94
if command -v selinuxenabled > /dev/null 2>&1 && selinuxenabled; then
_DOCKERD_ROOTLESS_SELINUX=1
export _DOCKERD_ROOTLESS_SELINUX
fi
# Re-exec the script via RootlessKit, so as to create unprivileged {user,mount,network} namespaces.
#
# --copy-up allows removing/creating files in the directories by creating tmpfs and symlinks
@ -105,5 +111,12 @@ else
# remove the symlinks for the existing files in the parent namespace if any,
# so that we can create our own files in our mount namespace.
rm -f /run/docker /run/containerd /run/xtables.lock
if [ -n "$_DOCKERD_ROOTLESS_SELINUX" ]; then
# iptables requires /run in the child to be relabeled. The actual /run in the parent is unaffected.
# https://github.com/containers/podman/blob/e6fc34b71aa9d876b1218efe90e14f8b912b0603/libpod/networking_linux.go#L396-L401
# https://github.com/moby/moby/issues/41230
chcon system_u:object_r:iptables_var_run_t:s0 /run
fi
exec dockerd $@
fi

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@ -37,6 +37,16 @@ func ErrDTypeNotSupported(driver, backingFs string) error {
// checkMultipleLowers parameter enables check for multiple lowerdirs,
// which is required for the overlay2 driver.
func SupportsOverlay(d string, checkMultipleLowers bool) error {
// We can't rely on go-selinux.GetEnabled() to detect whether SELinux is enabled,
// because RootlessKit doesn't mount /sys/fs/selinux in the child: https://github.com/rootless-containers/rootlesskit/issues/94
// So we check $_DOCKERD_ROOTLESS_SELINUX, which is set by dockerd-rootless.sh .
if os.Getenv("_DOCKERD_ROOTLESS_SELINUX") == "1" {
// Kernel 5.11 introduced support for rootless overlayfs, but incompatible with SELinux,
// so fallback to fuse-overlayfs.
// https://github.com/moby/moby/issues/42333
return errors.New("overlay is not supported for Rootless with SELinux")
}
td, err := ioutil.TempDir(d, "check-overlayfs-support")
if err != nil {
return err