#!/bin/sh # Wrapper around openssl to generate self-signed X.509 server # certificates or Certificate Signing Requests, or DKIM private keys. # Inspired from make-ssl-cert(8) and opendkim-genkey(8). # # Copyright © 2014 Guilhem Moulin # # This program is free software: you can redistribute it and/or modify # it under the terms of the GNU General Public License as published by # the Free Software Foundation, either version 3 of the License, or # (at your option) any later version. # # This program is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the # GNU General Public License for more details. # # You should have received a copy of the GNU General Public License # along with this program. If not, see . set -ue PATH=/usr/bin:/bin # Default values type=rsa bits= hash= force=0 config= pubkey=pubkey.pem privkey=privkey.pem dns= ou= cn= usage= mode= owner= group= usage() { cat >&2 <<- EOF Usage: $0 command [OPTIONS] Command: x509: generate a self-signed X.509 server certificate csr: generate a Certificate Signing Request dkim: generate a private key (to use for DKIM signing) keypair: generate a key pair Options: -t type: key type (default: rsa) -b bits: key length or EC curve (default: 2048 for RSA, 1024 for DSA, secp224r1 for ECDSA) -h digest: digest algorithm --ou: organizational Unit Name; can be repeated --cn: common Name (default: \$(hostname --fqdn) --dns: hostname for AltName; can be repeated -f: force; can be repeated (0: don't overwrite, default; 1: reuse private key if it exists; 2: overwrite both keys if they exist) --config: configuration file --pubkey: public key file (default: pubkey.pem) --privkey: private key file (default: privkey.pem) --usage: key usage (default: digitalSignature,keyEncipherment,keyCertSign) --mode: set privkey's permission mode (default: 0600) --owner: set privkey's owner (default: the process' current owner) --group: set privkey's group (default: the process' current group) Return values: 0 The key pair was successfully generated 1 The public or private key file exists, and -f is not set 2 The key generation failed EOF } dkiminfo() { echo "Add the following TXT record to your DNS zone:" echo "${cn:-$(date +%Y%m%d)}._domainkey\tIN\tTXT ( " # See https://tools.ietf.org/html/rfc4871#section-3.6.1 # t=s: the "i=" domain in signature headers MUST NOT be a subdomain of "d=" # s=email: limit DKIM signing to email openssl pkey -pubout <"$privkey" | sed '/^--.*--$/d' \ | { echo -n "v=DKIM1; k=$type; t=s; s=email; p="; tr -d '\n'; } \ | fold -w 250 \ | { sed 's/.*/\t"&"/'; echo ' )'; } } [ $# -gt 0 ] || { usage; exit 2; } cmd="$1"; shift case "$cmd" in x509|csr|dkim|keypair) ;; *) echo "Unrecognized command: $cmd" >&2; exit 2 esac nou=1 while [ $# -gt 0 ]; do case "$1" in -t) shift; type="$1";; -t*) type="${1#-t}";; -b) shift; bits="$1";; -b*) bits="${1#-b}";; -h) shift; hash="$1";; -h*) hash="${1#-h}";; --dns=?*) dns="${dns:+$dns, }DNS:${1#--dns=}";; --cn=?*) cn="${1#--cn=}";; --ou=?*) ou="${ou:+$ou\n}$nou.organizationalUnitName = ${1#--ou=}" nou=$(( 1 + $nou ));; -f) force=$(( 1 + $force ));; --pubkey=?*) pubkey="${1#--pubkey=}";; --privkey=?*) privkey="${1#--privkey=}";; --usage=?*) usage="${usage:+$usage,}${1#--usage=}";; --config=?*) config="${1#--config=}";; --mode=?*) mode="${1#--mode=}";; --owner=?*) owner="${1#--owner=}";; --group=?*) group="${1#--group=}";; --help) usage; exit;; *) echo "Unrecognized argument: $1" >&2; exit 2 esac shift; done case "$type" in # XXX: genrsa and dsaparam have been deprecated in favor of genpkey. # genpkey can also create explicit EC parameters, but not named. rsa) genkey=genrsa; genkeyargs="-f4 ${bits:-2048}";; dsa) genkey=dsaparam; genkeyargs="-noout -genkey ${bits:-1024}";; # See 'openssl ecparam -list_curves' for the list of supported # curves. StrongSwan doesn't support explicit curve parameters # (however explicit parameters might be required to make exotic # curves work with some clients.) ecdsa) genkey=ecparam genkeyargs="-noout -name ${bits:-secp224r1} -param_enc named_curve -genkey";; *) echo "Unrecognized key type: $type" >&2; exit 2 esac if [ "$cmd" = x509 -o "$cmd" = csr ]; then case "$hash" in md5|rmd160|sha1|sha224|sha256|sha384|sha512|'') ;; *) echo "Invalid digest algorithm: $hash" >&2; exit 2; esac [ "$cn" ] || cn="$(hostname --fqdn)" [ ${#cn} -le 64 ] || { echo "CommonName too long: $cn" >&2; exit 2; } fi if [ -z "$config" -a \( "$cmd" = x509 -o "$cmd" = csr \) ]; then config=$(mktemp) || exit 2 trap 'rm -f "$config"' EXIT # see /usr/share/ssl-cert/ssleay.cnf cat >"$config" <<- EOF [ req ] distinguished_name = req_distinguished_name prompt = no policy = policy_anything req_extensions = v3_req x509_extensions = v3_req [ req_distinguished_name ] organizationName = Fripost organizationalUnitName = SSLcerts $(echo "$ou") commonName = ${cn:-/} [ v3_req ] subjectAltName = email:admin@fripost.org${dns:+, $dns} basicConstraints = critical, CA:FALSE # https://security.stackexchange.com/questions/24106/which-key-usages-are-required-by-each-key-exchange-method keyUsage = critical, ${usage:-digitalSignature, keyEncipherment, keyCertSign} subjectKeyIdentifier = hash EOF fi if [ -s "$privkey" -a $force -eq 0 ]; then echo "Error: private key exists: $privkey" >&2 [ "$cmd" = dkim ] && dkiminfo exit 1 elif [ ! -s "$privkey" -o $force -ge 2 ]; then install --mode="${mode:-0600}" ${owner:+--owner="$owner"} ${group:+--group="$group"} /dev/null "$privkey" || exit 2 openssl $genkey -rand /dev/urandom $genkeyargs >"$privkey" || exit 2 [ "$cmd" = dkim ] && { dkiminfo; exit; } fi if [ "$cmd" = x509 -a "$pubkey" = "$privkey" ]; then pubkey=$(mktemp) openssl req -config "$config" -new -x509 ${hash:+-$hash} -days 3650 -key "$privkey" >"$pubkey" || exit 2 cat "$pubkey" >>"$privkey" || exit 2 rm -f "$pubkey" elif [ "$cmd" = x509 -o "$cmd" = csr ]; then if [ -s "$pubkey" -a $force -eq 0 ]; then echo "Error: public key exists: $pubkey" >&2 exit 1 else [ "$cmd" = x509 ] && x509=-x509 || x509= openssl req -config "$config" -new $x509 ${hash:+-$hash} -days 3650 -key "$privkey" >"$pubkey" || exit 2 fi elif [ "$cmd" = keypair -a "$pubkey" ]; then openssl pkey -pubout <"$privkey" >"$pubkey" fi