name : fetch-ocsp-response #!/usr/libexec/platform-python # -*- coding: utf-8 -*- # nghttp2 - HTTP/2 C Library # Copyright (c) 2015 Tatsuhiro Tsujikawa # Permission is hereby granted, free of charge, to any person obtaining # a copy of this software and associated documentation files (the # "Software"), to deal in the Software without restriction, including # without limitation the rights to use, copy, modify, merge, publish, # distribute, sublicense, and/or sell copies of the Software, and to # permit persons to whom the Software is furnished to do so, subject to # the following conditions: # The above copyright notice and this permission notice shall be # included in all copies or substantial portions of the Software. # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, # EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF # MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND # NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE # LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION # OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION # WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. # This program was translated from the program originally developed by # h2o project (https://github.com/h2o/h2o), written in Perl. It had # the following copyright notice: # Copyright (c) 2015 DeNA Co., Ltd. # # Permission is hereby granted, free of charge, to any person obtaining a copy # of this software and associated documentation files (the "Software"), to # deal in the Software without restriction, including without limitation the # rights to use, copy, modify, merge, publish, distribute, sublicense, and/or # sell copies of the Software, and to permit persons to whom the Software is # furnished to do so, subject to the following conditions: # # The above copyright notice and this permission notice shall be included in # all copies or substantial portions of the Software. # # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, # FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE # AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING # FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS # IN THE SOFTWARE. from __future__ import unicode_literals import argparse import io import os import os.path import re import shutil import subprocess import sys import tempfile # make this program work for both Python 3 and Python 2. try: from urllib.parse import urlparse stdout_bwrite = sys.stdout.buffer.write except ImportError: from urlparse import urlparse stdout_bwrite = sys.stdout.write def die(msg): sys.stderr.write(msg) sys.stderr.write('\n') sys.exit(255) def tempfail(msg): sys.stderr.write(msg) sys.stderr.write('\n') sys.exit(os.EX_TEMPFAIL) def run_openssl(args, allow_tempfail=False): buf = io.BytesIO() try: p = subprocess.Popen(args, stdout=subprocess.PIPE) except Exception as e: die('failed to invoke {}:{}'.format(args, e)) try: while True: data = p.stdout.read() if len(data) == 0: break buf.write(data) if p.wait() != 0: raise Exception('nonzero return code {}'.format(p.returncode)) return buf.getvalue() except Exception as e: msg = 'OpenSSL exited abnormally: {}:{}'.format(args, e) tempfail(msg) if allow_tempfail else die(msg) def read_file(path): with open(path, 'rb') as f: return f.read() def write_file(path, data): with open(path, 'wb') as f: f.write(data) def detect_openssl_version(cmd): return run_openssl([cmd, 'version']).decode('utf-8').strip() def extract_ocsp_uri(cmd, cert_fn): # obtain ocsp uri ocsp_uri = run_openssl( [cmd, 'x509', '-in', cert_fn, '-noout', '-ocsp_uri']).decode('utf-8').strip() if not re.match(r'^https?://', ocsp_uri): die('failed to extract ocsp URI from {}'.format(cert_fn)) return ocsp_uri def save_issuer_certificate(issuer_fn, cert_fn): # save issuer certificate chain = read_file(cert_fn).decode('utf-8') m = re.match( r'.*?-----END CERTIFICATE-----.*?(-----BEGIN CERTIFICATE-----.*?-----END CERTIFICATE-----)', chain, re.DOTALL) if not m: die('--issuer option was not used, and failed to extract issuer certificate from the certificate') write_file(issuer_fn, (m.group(1) + '\n').encode('utf-8')) def send_and_receive_ocsp(respder_fn, cmd, cert_fn, issuer_fn, ocsp_uri, ocsp_host, openssl_version): # obtain response (without verification) sys.stderr.write('sending OCSP request to {}\n'.format(ocsp_uri)) args = [ cmd, 'ocsp', '-issuer', issuer_fn, '-cert', cert_fn, '-url', ocsp_uri, '-noverify', '-respout', respder_fn ] ver = openssl_version.lower() if ver.startswith('openssl 1.0.') or ver.startswith('libressl '): args.extend(['-header', 'Host', ocsp_host]) resp = run_openssl(args, allow_tempfail=True) return resp.decode('utf-8') def verify_response(cmd, tempdir, issuer_fn, respder_fn): # verify the response sys.stderr.write('verifying the response signature\n') verify_fn = os.path.join(tempdir, 'verify.out') # try from exotic options allextra = [ # for comodo ['-VAfile', issuer_fn], # these options are only available in OpenSSL >= 1.0.2 ['-partial_chain', '-trusted_first', '-CAfile', issuer_fn], # for OpenSSL <= 1.0.1 ['-CAfile', issuer_fn], ] for extra in allextra: with open(verify_fn, 'w+b') as f: args = [cmd, 'ocsp', '-respin', respder_fn] args.extend(extra) p = subprocess.Popen(args, stdout=f, stderr=f) if p.wait() == 0: # OpenSSL <= 1.0.1, openssl ocsp still returns exit # code 0 even if verification was failed. So check # the error message in stderr output. f.seek(0) if f.read().decode('utf-8').find( 'Response Verify Failure') != -1: continue sys.stderr.write('verify OK (used: {})\n'.format(extra)) return True sys.stderr.write(read_file(verify_fn).decode('utf-8')) return False def fetch_ocsp_response(cmd, cert_fn, tempdir, issuer_fn=None): openssl_version = detect_openssl_version(cmd) sys.stderr.write( 'fetch-ocsp-response (using {})\n'.format(openssl_version)) ocsp_uri = extract_ocsp_uri(cmd, cert_fn) ocsp_host = urlparse(ocsp_uri).netloc if not issuer_fn: issuer_fn = os.path.join(tempdir, 'issuer.crt') save_issuer_certificate(issuer_fn, cert_fn) respder_fn = os.path.join(tempdir, 'resp.der') resp = send_and_receive_ocsp( respder_fn, cmd, cert_fn, issuer_fn, ocsp_uri, ocsp_host, openssl_version) sys.stderr.write('{}\n'.format(resp)) # OpenSSL 1.0.2 still returns exit code 0 even if ocsp responder # returned error status (e.g., trylater(3)) if resp.find('Responder Error:') != -1: raise Exception('responder returned error') if not verify_response(cmd, tempdir, issuer_fn, respder_fn): tempfail('failed to verify the response') # success res = read_file(respder_fn) stdout_bwrite(res) if __name__ == '__main__': parser = argparse.ArgumentParser( description= '''The command issues an OCSP request for given server certificate, verifies the response and prints the resulting DER.''', epilog= '''The command exits 0 if successful, or 75 (EX_TEMPFAIL) on temporary error. Other exit codes may be returned in case of hard errors.''') parser.add_argument( '--issuer', metavar='FILE', help= 'issuer certificate (if omitted, is extracted from the certificate chain)') parser.add_argument('--openssl', metavar='CMD', help='openssl command to use (default: "openssl")', default='openssl') parser.add_argument('certificate', help='path to certificate file to validate') args = parser.parse_args() tempdir = None try: # Python3.2 has tempfile.TemporaryDirectory, which has nice # feature to delete its tree by cleanup() function. We have # to support Python2.7, so we have to do this manually. tempdir = tempfile.mkdtemp() fetch_ocsp_response(args.openssl, args.certificate, tempdir, args.issuer) finally: if tempdir: shutil.rmtree(tempdir)