X-Git-Url: https://iankelling.org/git/?p=vpn-setup;a=blobdiff_plain;f=vpn-mk-client-cert;h=f4e5762d78c52024dfad15245960599140c813a6;hp=4e41bacf8297ba31f032d70c5e31ecafbec1e444;hb=HEAD;hpb=e1e49f58b89db5ea637f2671bf8c1ce35af68e5f

diff --git a/vpn-mk-client-cert b/vpn-mk-client-cert
index 4e41bac..7bad544 100755
--- a/vpn-mk-client-cert
+++ b/vpn-mk-client-cert
@@ -1,5 +1,12 @@
 #!/bin/bash
-# Copyright (C) 2016 Ian Kelling
+# I, Ian Kelling, follow the GNU license recommendations at
+# https://www.gnu.org/licenses/license-recommendations.en.html. They
+# recommend that small programs, < 300 lines, be licensed under the
+# Apache License 2.0. This file contains or is part of one or more small
+# programs. If a small program grows beyond 300 lines, I plan to switch
+# its license to GPL.
+
+# Copyright 2024 Ian Kelling
 
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -13,90 +20,163 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-# usage: $0 SERVER_HOST [DEST_HOST]
-# ssh to SERVER_HOST, create a cert & client config, put it on
-# DEST_HOST, or localhost by default. Assumes server was setup
-# by the other script in this dir.
 
 set -eE -o pipefail
 trap 'echo "$0:$LINENO:error: \"$BASH_COMMAND\" returned $?" >&2' ERR
 
 [[ $EUID == 0 ]] || exec sudo -E "$BASH_SOURCE" "$@"
 
+readonly this_file="$(readlink -f -- "${BASH_SOURCE[0]}")"
+this_dir="${this_file%/*}"
+
+
 usage() {
-    cat <<EOF
+  cat <<'EOF'
 usage: ${0##*/} VPN_SERVER_HOST
 
--c CLIENT_HOST   default is localhost
+-b COMMON_NAME   By default, use $CLIENT_HOST or if it is not given,
+                 $HOSTNAME. If the cert already exists on the server,
+                 with the CLIENT_NAME name, we use the existing one. See
+                 comment below if we ever want to check existing common
+                 names. They must be unique per server, so you can use
+                 $(uuidgen) if needed. You used to be able to create
+                 multiple with the same name, but not connect at the
+                 same time, but now, the generator keeps track, so you
+                 can't generate.
+
+-c CLIENT_HOST   Default is localhost. Else we ssh to root@CLIENT_HOST.
+-f               Force. Proceed even if cert already exists.
 -n CONFIG_NAME   default is client
+-o SERVER_CONFIG_NAME  Default is CONFIG_NAME
+-r               Install certs to the current directory instead of /etc/openvpn/client
+-s SCRIPT_PATH   Use custom up/down script at SCRIPT_PATH. If client host is
+                 not localhost, the script is copied to it. The default
+                 script used to be /etc/openvpn/update-resolv-conf, but now
+                 that systemd-resolved is becoming popular, there is no default.
+
+Environment variable: SSH_CONFIG_FILE_OVERRIDE
 
 Generate a client cert and config and install it on locally or on
 CLIENT_HOST if given.  Uses default config options, and expects be able
-to ssh to VPN_SERVER_HOST and CLIENT_HOST.
+to ssh to VPN_SERVER_HOST and CLIENT_HOST as root, or if CLIENT_HOST is
+localhost, just to sudo this script as root.
+
+
+
+
+Note: Uses GNU getopt options parsing style
 EOF
-    exit ${1:-0}
+  exit ${1:-0}
 }
 
+# to get the common name
+# cn=$(s openssl x509 -noout -nameopt multiline -subject \
+  #        -in /etc/openvpn/client/mail.crt | \
+  #          sed -rn 's/^\s*commonName\s*=\s*(.*)/\1/p')
+
+
+####### begin command line parsing and checking ##############
+
 shell="bash -c"
 name=client
-
-temp=$(getopt -l help hc:n: "$@") || usage 1
+client_host=$CLIENT_HOST
+force=false
+rel=false
+if [[ $SSH_CONFIG_FILE_OVERRIDE ]]; then
+  ssh_arg="-F $SSH_CONFIG_FILE_OVERRIDE"
+fi
+
+temp=$(getopt -l help hb:c:fn:o:rs: "$@") || usage 1
 eval set -- "$temp"
 while true; do
-    case $1 in
-        -c) shell="ssh $2"; shift 2 ;;
-        -n) name="$2"; shift 2 ;;
-        -h|--help) usage ;;
-        --) shift; break ;;
-        *) echo "$0: Internal error! unexpected args: $*" ; exit 1 ;;
-    esac
+  case $1 in
+    -b) common_name="$2"; shift 2 ;;
+    -c) client_host=$2; shell="ssh $ssh_arg root@$client_host"; shift 2 ;;
+    -f) force=true; shift ;;
+    -n) name="$2"; shift 2 ;;
+    -o) server_name="$2"; shift 2 ;;
+    -r) rel=true; shift ;;
+    -s) script="$2"; shift 2 ;;
+    -h|--help) usage ;;
+    --) shift; break ;;
+    *) echo "$0: Internal error! unexpected args: $*" ; exit 1 ;;
+  esac
 done
-host=$1
-[[ $host ]] || usage 1
 
-# bash or else we get motd spam. note sleep 2, sleep 1 failed.
-ssh $host bash <<EOF | $shell 'id -u | grep -xF 0 || s=sudo; $s tar xzv -C /etc/openvpn/client'
-set -eE -o pipefail
-cd /etc/openvpn/easy-rsa
-source vars >/dev/null
+if [[ $client_host ]] && $rel; then
+  echo "$0: error client_host and -r specified. use one or the other"
+  exit 1
+fi
 
-# uuidgen because common name must be unique
-{ echo -e '\n\n\n\n\n'\$(uuidgen)'\n\n\n\n\n'; sleep 2; echo -e 'y\ny\n'; } | ./build-key $name &>/dev/null
 
-d=\$(mktemp -d)
-cp /etc/openvpn/easy-rsa/keys/ca.crt \$d/$name-ca.crt
-mv /etc/openvpn/easy-rsa/keys/$name.{crt,key} \$d
+if [[ ! $server_name ]]; then
+  server_name="$name"
+fi
 
-tar cz -C \$d .
-rm -rf \$d
-EOF
+if [[ ! $common_name ]]; then
+  if [[ $client_host ]]; then
+    common_name=$client_host
+  else
+    common_name=$HOSTNAME
+  fi
+fi
 
-cat > /etc/openvpn/client/$name.conf <<EOF
-# From example config, from debian stretch as of 1-2017
+host=$1
+[[ $host ]] || usage 1
+
+####### end command line parsing and checking ##############
+
+
+if $rel; then
+  f=$name.crt
+  keydir=.
+else
+  f=/etc/openvpn/client/$name.crt
+  keydir=/etc/openvpn/client
+fi
+
+
+if ! $force; then
+  cert_to_test=$f
+  if [[ $client_host ]]; then
+    cert_to_test=$(mktemp)
+    ssh $ssh_arg root@$client_host cat $f 2>/dev/null >$cert_to_test ||:
+  fi
+  if openssl x509 -checkend $(( 60 * 60 * 24 * 30 )) -noout -in $cert_to_test &>/dev/null; then
+    if [[ $client_host ]]; then
+      prefix="$shell"
+    fi
+    if $prefix test -s $keydir/ta-$name.key -a -s $keydir/ca-$name.crt; then
+      echo "$0: cert already exists. exiting early"
+      exit 0
+    fi
+  fi
+fi
+
+port=$(echo '/^port/ {print $2}' | ssh $ssh_arg root@$host awk -f - /etc/openvpn/server/$name.conf | tail -n1)
+
+$shell "dd of=$keydir/$name.conf" <<EOF
+# From example config, from debian stretch to buster
 client
 dev tun
 proto udp
-remote $host 1194
+remote $host $port
 resolv-retry infinite
 nobind
 persist-key
-persist-tun
-ca $name-ca.crt
+# persist-tun was here, but if the vpn goes down this makes
+# the whole thing get stuck if the vpn is our default route
+# unless we set a special route out just for the vpn.
+# todo: investigate.
+ca ca-$name.crt
 cert $name.crt
 key $name.key
 # disabled for better performance
 #comp-lzo
 verb 3
 
-# This script will update local dns
-# to what the server sends, if it sends dns.
-script-security 2
-up /etc/openvpn/update-resolv-conf
-down /etc/openvpn/update-resolv-conf
-
 # matching server config
-cipher aes-256-cbc
-
+cipher AES-256-CBC
 
 # example config has the commented line, but this other thing looks stronger,
 # and I've seen it in a vpn provider I trust
@@ -105,4 +185,51 @@ remote-cert-tls server
 
 # more resilient when running as nonroot
 persist-key
+
+# See comments in server side configuration.
+# The minimum of the client & server config is what is used by openvpn.
+reneg-sec 432000
+
+tls-auth ta-$name.key 1
 EOF
+
+if [[ $script ]]; then
+  $shell "tee -a /etc/openvpn/client/$name.conf" <<EOF
+script-security 2
+up "$script"
+down "$script"
+EOF
+
+  if [[ $client_host && $script ]]; then
+    $shell "dd of=$script" <$script
+    $shell "chmod +x $script"
+  fi
+fi
+
+if ! $rel; then
+  $shell 'cd /etc/openvpn; for f in client/*; do ln -sf $f .; done'
+fi
+
+if ! $rel; then
+  dirarg="-C $keydir"
+fi
+
+# bash or else we get motd spam. note sleep 2, sleep 1 failed.
+$shell '[[ -e /etc/openvpn ]] || apt install openvpn'
+hostssh="ssh $arg root@$host"
+if ! $hostssh bash -s -- $server_name $common_name < $this_dir/client-cert-helper \
+    |  $shell "id -u | grep -xF 0 || s=sudo; \$s tar xzv $dirarg"; then
+  echo $hostssh cat /tmp/vpn-mk-client-cert.log:
+  $hostssh cat /tmp/vpn-mk-client-cert.log
+  echo EOF for root@$host:/tmp/vpn-mk-client-cert.log
+  exit 1
+fi
+
+
+
+if ! $shell "test -s $f"; then
+  # if common name is not unique, you get empty file. and if we didn't silence
+  # build-key, you'd see an error "TXT_DB error number 2"
+  echo "$0: error: $f is empty or otherwise bad. is this common name unique?"
+  exit 1
+fi