test: check if we correctly handle invalid UTF-8 in mount stuff

Provides coverage for #27611.

test/units/testsuite-07.mount-invalid-chars.sh

@@ -0,0 +1,70 @@
+#!/usr/bin/env bash
+# SPDX-License-Identifier: LGPL-2.1-or-later
+set -eux
+set -o pipefail
+
+# Don't send invalid characters over dbus if a mount contains them
+
+at_exit() {
+    mountpoint -q /proc/1/mountinfo && umount /proc/1/mountinfo
+    [[ -e /tmp/fstab.bak ]] && mv -f /tmp/fstab /etc/fstab
+    rm -f /run/systemd/system/foo-*.mount
+    systemctl daemon-reload
+}
+
+trap at_exit EXIT
+
+# Check invalid characters directly in /proc/mountinfo
+#
+# This is a bit tricky (and hacky), since we have to temporarily replace
+# PID 1's /proc/mountinfo, but we have to keep the original mounts intact,
+# otherwise systemd would unmount them on reload
+TMP_MOUNTINFO="$(mktemp)"
+
+cp /proc/1/mountinfo "$TMP_MOUNTINFO"
+# Add a mount entry with a "Unicode non-character" in it
+echo -ne '69 1 252:2 / /foo/mountinfo rw,relatime shared:1 - cifs //foo\ufffebar rw,seclabel\n' >>"$TMP_MOUNTINFO"
+mount --bind "$TMP_MOUNTINFO" /proc/1/mountinfo
+systemctl daemon-reload
+# On affected versions this would throw an error:
+#   Failed to get properties: Bad message
+systemctl status foo-mountinfo.mount
+
+umount /proc/1/mountinfo
+systemctl daemon-reload
+rm -f "$TMP_MOUNTINFO"
+
+# Check invalid characters in a mount unit
+#
+# systemd already handles this and refuses to load the invalid string, e.g.:
+#   foo-fstab.mount:9: String is not UTF-8 clean, ignoring assignment: What=//localhost/foo<6F><6F><EFBFBD>bar
+#
+# a) Unit generated from /etc/fstab
+[[ -e /etc/fstab ]] && cp -f /etc/fstab /tmp/fstab.bak
+
+echo -ne '//localhost/foo\ufffebar  /foo/fstab  cifs defaults 0 0\n' >/etc/fstab
+systemctl daemon-reload
+[[ "$(systemctl show -P UnitFileState foo-fstab.mount)" == bad ]]
+
+# b) Unit generated from /etc/fstab (but the invalid character is in options)
+echo -ne '//localhost/foobar  /foo/fstab/opt  cifs nosuid,a\ufffeb,noexec 0 0\n' >/etc/fstab
+systemctl daemon-reload
+[[ "$(systemctl show -P UnitFileState foo-fstab-opt.mount)" == bad ]]
+rm -f /etc/fstab
+
+[[ -e /tmp/fstab.bak ]] && mv -f /tmp/fstab /etc/fstab
+systemctl daemon-reload
+
+# c) Mount unit
+mkdir -p /run/systemd/system
+echo -ne '[Mount]\nWhat=//localhost/foo\ufffebar\nWhere=/foo/unit\nType=cifs\nOptions=noexec\n' >/run/systemd/system/foo-unit.mount
+systemctl daemon-reload
+[[ "$(systemctl show -P UnitFileState foo-unit.mount)" == bad ]]
+rm -f /run/systemd/system/foo-unit.mount
+
+# d) Mount unit (but the invalid character is in Options=)
+mkdir -p /run/systemd/system
+echo -ne '[Mount]\nWhat=//localhost/foobar\nWhere=/foo/unit/opt\nType=cifs\nOptions=noexec,a\ufffeb,nosuid\n' >/run/systemd/system/foo-unit-opt.mount
+systemctl daemon-reload
+[[ "$(systemctl show -P UnitFileState foo-unit-opt.mount)" == bad ]]
+rm -f /run/systemd/system/foo-unit-opt.mount