net-firewall/nftables: add emergency pkg_preinst sanity check

The idea here is that we check just before merging whether the freshly
built `nft` binary can safely (pretend) reload the system ruleset.

A significant number of recent regressions have manifested in immediate
segfaults when doing this, so it's worth doing the safety check (it's
not as if it's niche or unlikely for a failure to occur at this point).

Those who want a failed check to be *fatal* can set NFTABLES_ABORT_ON_RELOAD_FAILURE=1.

Otherwise, it's just a warning.

Bug: https://bugs.gentoo.org/852662
Thanks-to: Kerin Millar <kfm@plushkava.net>
Signed-off-by: Sam James <sam@gentoo.org>

1 files changed, 218 insertions, 0 deletions

diff --git a/net-firewall/nftables/nftables-1.0.4-r2.ebuild b/net-firewall/nftables/nftables-1.0.4-r2.ebuild
new file mode 100644
index 000000000000..e15c2462f85d
--- /dev/null
+++ b/net-firewall/nftables/nftables-1.0.4-r2.ebuild
@@ -0,0 +1,218 @@
+# Copyright 1999-2022 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=8
+
+DISTUTILS_OPTIONAL=1
+PYTHON_COMPAT=( python3_{8..11} )
+VERIFY_SIG_OPENPGP_KEY_PATH="${BROOT}"/usr/share/openpgp-keys/netfilter.org.asc
+inherit edo linux-info distutils-r1 systemd verify-sig
+
+DESCRIPTION="Linux kernel (3.13+) firewall, NAT and packet mangling tools"
+HOMEPAGE="https://netfilter.org/projects/nftables/"
+
+if [[ ${PV} =~ ^[9]{4,}$ ]]; then
+	inherit autotools git-r3
+	EGIT_REPO_URI="https://git.netfilter.org/${PN}"
+
+	BDEPEND="
+		sys-devel/bison
+		sys-devel/flex
+	"
+else
+	SRC_URI="https://netfilter.org/projects/nftables/files/${P}.tar.bz2
+		verify-sig? ( https://netfilter.org/projects/nftables/files/${P}.tar.bz2.sig )"
+	KEYWORDS="~amd64 ~arm ~arm64 ~hppa ~ia64 ~mips ~ppc ~ppc64 ~riscv ~sparc ~x86"
+	BDEPEND+="verify-sig? ( sec-keys/openpgp-keys-netfilter )"
+fi
+
+LICENSE="GPL-2"
+SLOT="0/1"
+IUSE="debug doc +gmp json libedit +modern-kernel python +readline static-libs test xtables"
+RESTRICT="test? ( userpriv ) !test? ( test )"
+
+RDEPEND="
+	>=net-libs/libmnl-1.0.4:0=
+	>=net-libs/libnftnl-1.2.2:0=
+	gmp? ( dev-libs/gmp:= )
+	json? ( dev-libs/jansson:= )
+	python? ( ${PYTHON_DEPS} )
+	readline? ( sys-libs/readline:= )
+	xtables? ( >=net-firewall/iptables-1.6.1:= )
+"
+
+DEPEND="${RDEPEND}"
+
+BDEPEND+="
+	virtual/pkgconfig
+	doc? (
+		app-text/asciidoc
+		>=app-text/docbook2X-0.8.8-r4
+	)
+	python? ( ${PYTHON_DEPS} )
+"
+
+REQUIRED_USE="
+	python? ( ${PYTHON_REQUIRED_USE} )
+	libedit? ( !readline )
+"
+
+pkg_setup() {
+	if kernel_is ge 3 13; then
+		if use modern-kernel && kernel_is lt 3 18; then
+			eerror "The modern-kernel USE flag requires kernel version 3.18 or newer to work properly."
+		fi
+		CONFIG_CHECK="~NF_TABLES"
+		linux-info_pkg_setup
+	else
+		eerror "This package requires kernel version 3.13 or newer to work properly."
+	fi
+}
+
+src_prepare() {
+	local PATCHES=(
+		"${FILESDIR}/nftables-1.0.4-revert-scanner-flags-move-to-own-scope.patch"
+	)
+	default
+
+	if [[ ${PV} =~ ^[9]{4,}$ ]] ; then
+		eautoreconf
+	fi
+
+	if use python; then
+		pushd py >/dev/null || die
+		distutils-r1_src_prepare
+		popd >/dev/null || die
+	fi
+}
+
+src_configure() {
+	local myeconfargs=(
+		# We handle python separately
+		--disable-python
+		--disable-static
+		--sbindir="${EPREFIX}"/sbin
+		$(use_enable debug)
+		$(use_enable doc man-doc)
+		$(use_with !gmp mini_gmp)
+		$(use_with json)
+		$(use_with libedit cli editline)
+		$(use_with readline cli readline)
+		$(use_enable static-libs static)
+		$(use_with xtables)
+	)
+	econf "${myeconfargs[@]}"
+
+	if use python; then
+		pushd py >/dev/null || die
+		distutils-r1_src_configure
+		popd >/dev/null || die
+	fi
+}
+
+src_compile() {
+	default
+
+	if use python; then
+		pushd py >/dev/null || die
+		distutils-r1_src_compile
+		popd >/dev/null || die
+	fi
+}
+
+src_test() {
+	emake check
+
+	edo tests/shell/run-tests.sh -v
+
+	# Need to rig up Python eclass if using this, but it doesn't seem to work
+	# for me anyway.
+	#cd tests/py || die
+	#"${EPYTHON}" nft-test.py || die
+}
+
+src_install() {
+	default
+
+	if ! use doc && [[ ! ${PV} =~ ^[9]{4,}$ ]]; then
+		pushd doc >/dev/null || die
+		doman *.?
+		popd >/dev/null || die
+	fi
+
+	# Do it here instead of in src_prepare to avoid eautoreconf
+	# rmdir lets us catch if more files end up installed in /etc/nftables
+	dodir /usr/share/doc/${PF}/skels/
+	mv "${ED}"/etc/nftables/osf "${ED}"/usr/share/doc/${PF}/skels/osf || die
+	rmdir "${ED}"/etc/nftables || die
+
+	local mksuffix="$(usex modern-kernel '-mk' '')"
+
+	exeinto /usr/libexec/${PN}
+	newexe "${FILESDIR}"/libexec/${PN}${mksuffix}.sh ${PN}.sh
+	newconfd "${FILESDIR}"/${PN}${mksuffix}.confd ${PN}
+	newinitd "${FILESDIR}"/${PN}${mksuffix}.init-r1 ${PN}
+	keepdir /var/lib/nftables
+
+	systemd_dounit "${FILESDIR}"/systemd/${PN}-restore.service
+
+	if use python ; then
+		pushd py >/dev/null || die
+		distutils-r1_src_install
+		popd >/dev/null || die
+	fi
+
+	find "${ED}" -type f -name "*.la" -delete || die
+}
+
+pkg_preinst() {
+	if [[ -d /sys/module/nf_tables ]] && [[ -x /sbin/nft ]] && [[ -z ${ROOT} ]]; then
+		if ! /sbin/nft -t list ruleset | "${ED}"/sbin/nft -c -f -; then
+			eerror "Your currently loaded ruleset cannot be parsed by the newly built instance of"
+			eerror "nft. This probably means that there is a regression introduced by v${PV}."
+			eerror "(To make the ebuild fail instead of warning, set NFTABLES_ABORT_ON_RELOAD_FAILURE=1.)"
+
+			if [[ -n ${NFTABLES_ABORT_ON_RELOAD_FAILURE} ]] ; then
+				die "Aborting because of failed nft reload!"
+			fi
+		fi
+	fi
+}
+
+pkg_postinst() {
+	local save_file
+	save_file="${EROOT}"/var/lib/nftables/rules-save
+
+	# In order for the nftables-restore systemd service to start
+	# the save_file must exist.
+	if [[ ! -f "${save_file}" ]]; then
+		( umask 177; touch "${save_file}" )
+	elif [[ $(( "$( stat --printf '%05a' "${save_file}" )" & 07177 )) -ne 0 ]]; then
+		ewarn "Your system has dangerous permissions for ${save_file}"
+		ewarn "It is probably affected by bug #691326."
+		ewarn "You may need to fix the permissions of the file. To do so,"
+		ewarn "you can run the command in the line below as root."
+		ewarn "    'chmod 600 \"${save_file}\"'"
+	fi
+
+	if has_version 'sys-apps/systemd'; then
+		elog "If you wish to enable the firewall rules on boot (on systemd) you"
+		elog "will need to enable the nftables-restore service."
+		elog "    'systemctl enable ${PN}-restore.service'"
+		elog
+		elog "If you are creating firewall rules before the next system restart"
+		elog "the nftables-restore service must be manually started in order to"
+		elog "save those rules on shutdown."
+	fi
+
+	if has_version 'sys-apps/openrc'; then
+		elog "If you wish to enable the firewall rules on boot (on openrc) you"
+		elog "will need to enable the nftables service."
+		elog "    'rc-update add ${PN} default'"
+		elog
+		elog "If you are creating or updating the firewall rules and wish to save"
+		elog "them to be loaded on the next restart, use the \"save\" functionality"
+		elog "in the init script."
+		elog "    'rc-service ${PN} save'"
+	fi
+}