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Diffstat (limited to '')
| -rwxr-xr-x | run.d/30-query-hostname | 98 |
1 files changed, 98 insertions, 0 deletions
diff --git a/run.d/30-query-hostname b/run.d/30-query-hostname new file mode 100755 index 0000000..d34ce06 --- /dev/null +++ b/run.d/30-query-hostname @@ -0,0 +1,98 @@ +#!/bin/sh +# +# 30-ask-hostname - request the user to type in the hostname of the local host +# +# Copyright © 2006-2009 martin f. krafft <madduck@madduck.net> +# Copyright © 2012 Ludovico Gardenghi <lu@dovi.co> +# Copyright © 2014 Josh Triplett <josh@joshtriplett.org> +# Copyright © 2015 Francois Marier <francois@debian.org> +# Copyright © 2017 Simó Albert i Beltran <sim6@probeta.net> +# Released under the terms of the Artistic Licence 2.0 +# +set -eu + +ME=molly-guard + +# Walk up the process tree until PID 1 is reached or a process with 'sshd' in +# its /proc/<pid>/cmdline is met. Return success if such a process is found. +is_child_of_sshd_or_mosh_server() { + pid=$$ + ppid=$PPID + # Be a bit paranoid with the guard, should some horribly broken system + # provide a strange process hierarchy. '[ $pid -ne 1 ]' should be enough for + # sane systems. + [ -z "$pid" ] || [ -z "$ppid" ] && return 2 + while [ $pid -gt 1 ] && [ $pid -ne $ppid ]; do + if egrep -q 'sshd|mosh-server' /proc/$ppid/cmdline; then + return 0 + fi + pid=$ppid + ppid=$(grep ^PPid: /proc/$pid/status | tr -dc 0-9) + done + return 1 +} + +[ -f "$MOLLYGUARD_SETTINGS" ] && . "$MOLLYGUARD_SETTINGS" + +PRETEND_SSH=0 +for arg in "$@"; do + case "$arg" in + (*-pretend-ssh) PRETEND_SSH=1;; + esac +done + +# require an interactive terminal connected to stdin +test -t 0 || exit 0 + +# we've been asked to always protect this host +case "${ALWAYS_QUERY_HOSTNAME:-0}" in + 0|false|False|no|No|off|Off) + # only run if we are being called over SSH, that is if the current terminal + # was created by sshd. + command -v tty >/dev/null 2>&1 || exit 0 + PTS=$(tty) + if ! pgrep -f "^sshd.+${PTS#/dev/}\>" >/dev/null \ + && [ -z "${SSH_CONNECTION:-}" ] \ + && ! is_child_of_sshd_or_mosh_server; then + if [ $PRETEND_SSH -eq 1 ]; then + echo "I: $ME: this is not an SSH session, but --pretend-ssh was given..." >&2 + else + exit 0 + fi + else + echo "W: $ME: SSH session detected!" >&2 + fi + ;; + *) + echo "I: $ME: $MOLLYGUARD_CMD is always molly-guarded on this system." >&2 + ;; +esac + +case "${USE_FQDN:-0}" in + 0|false|False|no|No|off|Off) + HOSTNAME="$(hostname --short)" + ;; + *) + HOSTNAME="$(hostname --fqdn)" + ;; +esac + +sigh() +{ + echo "Good thing I asked; I won't $MOLLYGUARD_CMD $HOSTNAME ..." >&2 + exit 1 +} + +trap 'echo;sigh' 1 2 3 9 10 12 15 + +echo -n "Please type in hostname of the machine to $MOLLYGUARD_CMD: " +read HOSTNAME_USER || : + +HOSTNAME="$(echo "$HOSTNAME" | tr '[:upper:]' '[:lower:]')" +HOSTNAME_USER="$(echo "$HOSTNAME_USER" | tr '[:upper:]' '[:lower:]')" + +[ "$HOSTNAME_USER" = "$HOSTNAME" ] || sigh + +trap - 1 2 3 9 10 12 15 + +exit 0 |