diskimage-builder/diskimage_builder/elements/rpm-distro/cleanup.d/99-selinux-fixfiles-restore
Alfredo Moralejo b1961e14ea Use SELinuxfs to check selinux status
Currently, the cleanup script is using existence of
semanage binary to check if selinux is enabled. However
this is misleading and can lead to problems when selinux
is disabled in a system where the binary exist.

This patch changes the detection logic to use /sys/fs/selinux
directory which is a in-memory filesystem created only when
selinux is really enabled.

Change-Id: I008f8bbc9c8414ce948c601e3907e27764e15a52
Related-Bug: 1706386
2017-07-26 18:57:25 +02:00

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#!/bin/bash
if [ ${DIB_DEBUG_TRACE:-1} -gt 0 ]; then
set -x
fi
set -eu
set -o pipefail
# parser isn't smart enough to figure out \
# dib-lint: disable=safe_sudo
# Here be dragons ... a previous dragon slayer helpfully pointed out in
# http://www.spinics.net/lists/selinux/msg17379.html
#
# Not all of the contexts defined by the offline system's
# file_contexts may be valid under the policy of the host on which
# you are running (e.g. if they run different distributions or even
# different releases of the same distribution), which will normally
# prevent setting those contexts (the kernel won't recognize them).
# If you have this issue, you'll need to run setfiles as root in a
# special domain, setfiles_mac_t, that is allowed to set contexts
# unknown to the host policy, and likely chrooted so that it doesn't
# ask the kernel whether the contexts are valid via
# /sys/fs/selinux/context. That is how livecd-creator supported
# creating images for other releases.
# One issue you might see without fixing selinux file labels is sshd
# will run in the kernel_t domain instead of the sshd_t domain, making
# ssh connections fail with "Unable to get valid context for <user>"
# error message. Other failures will occur too.
# XXX: is it really valid to build rpm-distros without this?
if [[ ! -f ${TARGET_ROOT}/etc/selinux/targeted/contexts/files/file_contexts ]]; then
echo "No selinux policy found in chroot, skipping..."
exit 0
fi
if [[ ! -x ${TARGET_ROOT}/usr/sbin/setfiles ]]; then
echo "Can not find setfiles in chroot!"
exit 1
fi
# If we're on a selinux system, enable permissive mode for
# setfiles_mac_t so we can relabel within the chroot without concern
# for whatever policy is in the host kernel. We will run under
# "runcon" to specifically allow this
_runcon=""
if [[ -d /sys/fs/selinux ]]; then
sudo semanage permissive -a setfiles_mac_t
_runcon="runcon -t setfiles_mac_t -- "
fi
# setfiles in > Fedora 26 added this flag:
# do not read /proc/mounts to obtain a list of
# non-seclabel mounts to be excluded from relabeling
# checks. Setting this option is useful where there is
# a non-seclabel fs mounted with a seclabel fs
# this describes our situation of being on a loopback device on
# an ubuntu system, say. See also
# https://bugzilla.redhat.com/show_bug.cgi?id=1472709
_dash_m=""
if [[ $DISTRO_NAME == "fedora" && $DIB_RELEASE -ge 26 ]]; then
_dash_m+="-m"
fi
IFS='|' read -ra SPLIT_MOUNTS <<< "$DIB_MOUNTPOINTS"
for MOUNTPOINT in "${SPLIT_MOUNTS[@]}"; do
if [ "${MOUNTPOINT}" != "/tmp/in_target.d" ] && [ "${MOUNTPOINT}" != "/dev" ]; then
sudo ${_runcon} chroot ${TARGET_ROOT} \
/usr/sbin/setfiles -F ${_dash_m} \
/etc/selinux/targeted/contexts/files/file_contexts ${MOUNTPOINT}
fi
done