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