initial commit

.gitignore

+private_key.pem
+domains.txt
+config.sh
+certs/*
+!certs/.keep

README.md

+# letsencrypt.sh
+
+letsencrypt client implemented as a shell-script

config.sh.example

+CA="https://acme-v01.api.letsencrypt.org"
+WELLKNOWN="/var/www/letsencrypt/.well-known/acme-challenge"

domains.txt.example

+example.org www.example.org
+example.com www.example.com wiki.example.com

json_to_pem.pl

+use strict;
+
+use Crypt::OpenSSL::RSA;
+use Crypt::OpenSSL::Bignum;
+use JSON;
+use File::Slurp;
+use MIME::Base64;
+
+my $json_file = "private_key.json";
+my $json_content = read_file($json_file);
+$json_content =~ tr/-/+/;
+$json_content =~ tr/_/\//;
+
+my $json = decode_json($json_content);
+
+my $n = Crypt::OpenSSL::Bignum->new_from_bin(decode_base64($json->{n}));
+my $e = Crypt::OpenSSL::Bignum->new_from_bin(decode_base64($json->{e}));
+my $d = Crypt::OpenSSL::Bignum->new_from_bin(decode_base64($json->{d}));
+my $p = Crypt::OpenSSL::Bignum->new_from_bin(decode_base64($json->{p}));
+my $q = Crypt::OpenSSL::Bignum->new_from_bin(decode_base64($json->{q}));
+
+my $rsa = Crypt::OpenSSL::RSA->new_key_from_parameters($n, $e, $d, $p, $q);
+
+print($rsa->get_private_key_string());

letsencrypt.sh

+#!/bin/bash
+
+set -e
+
+source config.sh
+
+declare -A header
+declare -A request
+
+urlbase64() {
+  base64 -w 0 | sed -r 's/=*$//g' | tr '+/' '-_'
+}
+
+pubExponent64="$(printf "%06x" "$(openssl rsa -in private_key.pem -noout -text | grep publicExponent | head -1 | cut -d' ' -f2)" | perl -pe 's/([0-9a-f]{2})/chr hex $1/gie' | urlbase64)"
+pubMod64="$(echo -n "$(openssl rsa -in private_key.pem -noout -modulus | cut -d'=' -f2 | perl -pe 's/([0-9a-f]{2})/chr hex $1/gie')" | urlbase64)"
+
+thumbprint="$(echo -n "$(echo -n '{"e":"'"${pubExponent64}"'","kty":"RSA","n":"'"${pubMod64}"'"}' | sha256sum | awk '{print $1}' | perl -pe 's/([0-9a-f]{2})/chr hex $1/gie')" | urlbase64)"
+
+signed_request() {
+  payload64="$(echo -n "${2}" | urlbase64)"
+
+  nonce="$(curl -s -I ${CA}/directory | grep Replay-Nonce | awk -F ': ' '{print $2}' | tr -d '\n\r')"
+
+  header='{"alg": "RS256", "jwk": {"e": "'"${pubExponent64}"'", "kty": "RSA", "n": "'"${pubMod64}"'"}}'
+
+  protected='{"alg": "RS256", "jwk": {"e": "'"${pubExponent64}"'", "kty": "RSA", "n": "'"${pubMod64}"'"}, "nonce": "'"${nonce}"'"}'
+  protected64="$(echo -n "${protected}" | urlbase64)"
+
+  signed64="$(echo -n "${protected64}.${payload64}" | openssl dgst -sha256 -sign private_key.pem | urlbase64)"
+
+  data='{"header": '"${header}"', "protected": "'"${protected64}"'", "payload": "'"${payload64}"'", "signature": "'"${signed64}"'"}'
+
+  curl -s -d "${data}" "${1}"
+}
+
+register() {
+  signed_request "${CA}/acme/new-reg" '{"resource": "new-reg", "agreement": "https://letsencrypt.org/documents/LE-SA-v1.0.1-July-27-2015.pdf"}'
+}
+
+sign_domain() {
+  domain="${1}"
+  altnames="${@}"
+  echo "Signing domain ${1} (${@})..."
+  if [ ! -e "certs/${domain}" ]; then
+    SAN=""
+    for altname in $altnames; do
+      SAN+="DNS:${altname}, "
+    done
+    SAN="$(echo -n $SAN | sed 's/,\s*$//g')"
+
+    mkdir "certs/${domain}"
+
+    echo "  + Generating private key..."
+    openssl genrsa -out "certs/${domain}/privkey.pem" 4096 > /dev/null
+    echo "  + Generating signing request..."
+    openssl req -new -sha256 -key "certs/${domain}/privkey.pem" -out "certs/${domain}/cert.csr" -subj "/CN=${domain}/" -reqexts SAN -config <(cat /etc/ssl/openssl.cnf <(printf "[SAN]\nsubjectAltName=${SAN}")) > /dev/null
+  fi
+
+  for altname in $altnames; do
+    echo "  + Requesting challenge for ${altname}..."
+    response="$(signed_request "${CA}/acme/new-authz" '{"resource": "new-authz", "identifier": {"type": "dns", "value": "'"${altname}"'"}}')"
+
+    challenge_token="$(echo $response | grep -Eo '"challenges":[^\[]*\[[^]]*]' | sed 's/{/\n{/g' | grep 'http-01' | grep -Eo '"token":\s*"[^"]*"' | cut -d'"' -f4 | sed 's/[^A-Za-z0-9_\-]/_/g')"
+    challenge_uri="$(echo $response | grep -Eo '"challenges":[^\[]*\[[^]]*]' | sed 's/{/\n{/g' | grep 'http-01' | grep -Eo '"uri":\s*"[^"]*"' | cut -d'"' -f4)"
+
+    keyauth="${challenge_token}.${thumbprint}"
+
+    echo -n "${keyauth}" > "${WELLKNOWN}/${challenge_token}"
+
+    echo "  + Responding to challenge for ${altname}..."
+    result="$(signed_request "${challenge_uri}" '{"resource": "challenge", "keyAuthorization": "'"${keyauth}"'"}')"
+
+    status="$(echo "${result}" | grep -Eo '"status":\s*"[^"]*"' | cut -d'"' -f4)"
+
+    if [ ! "${status}" = "pending" ] && [ ! "${status}" = "valid" ]; then
+      echo "  + Challenge is invalid!"
+      exit 1
+    fi
+
+    while [ ! "${status}" = "valid" ]; do
+      status="$(curl -s "${challenge_uri}" | grep -Eo '"status":\s*"[^"]*"' | cut -d'"' -f4)"
+    done
+
+    echo "  + Challenge is valid!"
+  done
+
+  echo "  + Requesting certificate..."
+  csr64="$(openssl req -in "certs/${domain}/cert.csr" -outform DER | urlbase64)"
+  crt64="$(signed_request "${CA}/acme/new-cert" '{"resource": "new-cert", "csr": "'"${csr64}"'"}' | base64 -w 64)"
+  echo -e "-----BEGIN CERTIFICATE-----\n${crt64}\n-----END CERTIFICATE-----\n" > "certs/${domain}/cert.pem"
+  echo "  + Done!"
+}
+
+cat domains.txt | sed 's/^\s*//g;s/\s*$//g' | grep -v '^#' | grep -v '^$' | while read line; do
+  sign_domain $line
+done