mirror of
https://github.com/certbot/certbot.git
synced 2026-08-02 03:22:14 +02:00
I think this is causing failures in some of our tests so this PR reverts the change until we can fix the problem.
The 2nd commit is to keep the change using more idiomatic wording in the changelog for another change that got included in this PR.
* Revert "Use built-in support for OCSP in cryptography >= 2.5 (#6603)"
This reverts commit 2ddaf3db04.
* keep changelog correction
This commit is contained in:
Brad Warren
+44
-153
@@ -1,79 +1,53 @@
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"""Tools for checking certificate revocation."""
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import logging
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import re
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from datetime import datetime, timedelta
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from subprocess import Popen, PIPE
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try:
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# Only cryptography>=2.5 has ocsp module
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# and signature_hash_algorithm attribute in OCSPResponse class
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from cryptography.x509 import ocsp # pylint: disable=import-error
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getattr(ocsp.OCSPResponse, 'signature_hash_algorithm')
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except (ImportError, AttributeError): # pragma: no cover
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ocsp = None # type: ignore
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from cryptography import x509
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from cryptography.hazmat.backends import default_backend
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from cryptography.hazmat.primitives import serialization
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from cryptography.hazmat.primitives import hashes # type: ignore
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from cryptography.exceptions import UnsupportedAlgorithm, InvalidSignature
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import requests
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from acme.magic_typing import Optional, Tuple # pylint: disable=unused-import, no-name-in-module
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from certbot import crypto_util
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from certbot import errors
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from certbot import util
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logger = logging.getLogger(__name__)
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class RevocationChecker(object):
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"""This class figures out OCSP checking on this system, and performs it."""
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"This class figures out OCSP checking on this system, and performs it."
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def __init__(self, enforce_openssl_binary_usage=False):
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def __init__(self):
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self.broken = False
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self.use_openssl_binary = enforce_openssl_binary_usage or not ocsp
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if self.use_openssl_binary:
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if not util.exe_exists("openssl"):
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logger.info("openssl not installed, can't check revocation")
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self.broken = True
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return
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if not util.exe_exists("openssl"):
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logger.info("openssl not installed, can't check revocation")
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self.broken = True
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return
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# New versions of openssl want -header var=val, old ones want -header var val
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test_host_format = Popen(["openssl", "ocsp", "-header", "var", "val"],
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stdout=PIPE, stderr=PIPE, universal_newlines=True)
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_out, err = test_host_format.communicate()
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if "Missing =" in err:
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self.host_args = lambda host: ["Host=" + host]
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else:
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self.host_args = lambda host: ["Host", host]
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# New versions of openssl want -header var=val, old ones want -header var val
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test_host_format = Popen(["openssl", "ocsp", "-header", "var", "val"],
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stdout=PIPE, stderr=PIPE, universal_newlines=True)
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_out, err = test_host_format.communicate()
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if "Missing =" in err:
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self.host_args = lambda host: ["Host=" + host]
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else:
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self.host_args = lambda host: ["Host", host]
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def ocsp_revoked(self, cert_path, chain_path):
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# type: (str, str) -> bool
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"""Get revoked status for a particular cert version.
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.. todo:: Make this a non-blocking call
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:param str cert_path: Path to certificate
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:param str chain_path: Path to intermediate cert
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:rtype bool or None:
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:returns: True if revoked; False if valid or the check failed
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:rtype: bool
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"""
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if self.broken:
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return False
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url, host = _determine_ocsp_server(cert_path)
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if not host or not url:
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url, host = self.determine_ocsp_server(cert_path)
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if not host:
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return False
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if self.use_openssl_binary:
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return self._check_ocsp_openssl_bin(cert_path, chain_path, host, url)
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else:
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return _check_ocsp_cryptography(cert_path, chain_path, url)
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def _check_ocsp_openssl_bin(self, cert_path, chain_path, host, url):
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# type: (str, str, str, str) -> bool
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# jdkasten thanks "Bulletproof SSL and TLS - Ivan Ristic" for documenting this!
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cmd = ["openssl", "ocsp",
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"-no_nonce",
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@@ -91,117 +65,33 @@ class RevocationChecker(object):
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except errors.SubprocessError:
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logger.info("OCSP check failed for %s (are we offline?)", cert_path)
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return False
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return _translate_ocsp_query(cert_path, output, err)
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def _determine_ocsp_server(cert_path):
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# type: (str) -> Tuple[Optional[str], Optional[str]]
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"""Extract the OCSP server host from a certificate.
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def determine_ocsp_server(self, cert_path):
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"""Extract the OCSP server host from a certificate.
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:param str cert_path: Path to the cert we're checking OCSP for
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:rtype tuple:
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:returns: (OCSP server URL or None, OCSP server host or None)
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:param str cert_path: Path to the cert we're checking OCSP for
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:rtype tuple:
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:returns: (OCSP server URL or None, OCSP server host or None)
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"""
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with open(cert_path, 'rb') as file_handler:
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cert = x509.load_pem_x509_certificate(file_handler.read(), default_backend())
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try:
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extension = cert.extensions.get_extension_for_class(x509.AuthorityInformationAccess)
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ocsp_oid = x509.AuthorityInformationAccessOID.OCSP
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descriptions = [description for description in extension.value
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if description.access_method == ocsp_oid]
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url = descriptions[0].access_location.value
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except (x509.ExtensionNotFound, IndexError):
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logger.info("Cannot extract OCSP URI from %s", cert_path)
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return None, None
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url = url.rstrip()
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host = url.partition("://")[2].rstrip("/")
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if host:
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return url, host
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else:
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logger.info("Cannot process OCSP host from URL (%s) in cert at %s", url, cert_path)
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return None, None
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def _check_ocsp_cryptography(cert_path, chain_path, url):
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# type: (str, str, str) -> bool
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# Retrieve OCSP response
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with open(chain_path, 'rb') as file_handler:
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issuer = x509.load_pem_x509_certificate(file_handler.read(), default_backend())
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with open(cert_path, 'rb') as file_handler:
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cert = x509.load_pem_x509_certificate(file_handler.read(), default_backend())
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builder = ocsp.OCSPRequestBuilder()
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builder = builder.add_certificate(cert, issuer, hashes.SHA1())
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request = builder.build()
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request_binary = request.public_bytes(serialization.Encoding.DER)
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response = requests.post(url, data=request_binary,
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headers={'Content-Type': 'application/ocsp-request'})
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if response.status_code != 200:
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logger.info("OCSP check failed for %s (are we offline?)", cert_path)
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return False
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response_ocsp = ocsp.load_der_ocsp_response(response.content)
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# Check OCSP response validity
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if response_ocsp.response_status != ocsp.OCSPResponseStatus.SUCCESSFUL:
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logger.error("Invalid OCSP response status for %s: %s",
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cert_path, response_ocsp.response_status)
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return False
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# Check OCSP signature
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try:
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_check_ocsp_response(response_ocsp, request, issuer)
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except UnsupportedAlgorithm as e:
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logger.error(str(e))
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except errors.Error as e:
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logger.error(str(e))
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except InvalidSignature:
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logger.error('Invalid signature on OCSP response for %s', cert_path)
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except AssertionError as error:
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logger.error('Invalid OCSP response for %s: %s.', cert_path, str(error))
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else:
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# Check OCSP certificate status
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logger.debug("OCSP certificate status for %s is: %s",
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cert_path, response_ocsp.certificate_status)
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return response_ocsp.certificate_status == ocsp.OCSPCertStatus.REVOKED
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return False
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def _check_ocsp_response(response_ocsp, request_ocsp, issuer_cert):
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"""Verify that the OCSP is valid for serveral criterias"""
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# Assert OCSP response corresponds to the certificate we are talking about
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if response_ocsp.serial_number != request_ocsp.serial_number:
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raise AssertionError('the certificate in response does not correspond '
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'to the certificate in request')
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# Assert signature is valid
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_check_ocsp_response_signature(response_ocsp, issuer_cert)
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# Assert issuer in response is the expected one
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if (not isinstance(response_ocsp.hash_algorithm, type(request_ocsp.hash_algorithm))
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or response_ocsp.issuer_key_hash != request_ocsp.issuer_key_hash
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or response_ocsp.issuer_name_hash != request_ocsp.issuer_name_hash):
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raise AssertionError('the issuer does not correspond to issuer of the certificate.')
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# Assert nextUpdate is in the future, and that thisUpdate is not too old
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if response_ocsp.next_update:
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if response_ocsp.next_update < datetime.now() - timedelta(minutes=5):
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raise AssertionError('next update is in the past.')
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interval = response_ocsp.next_update - response_ocsp.this_update
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if datetime.now() - response_ocsp.this_update > interval + timedelta(minutes=5):
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raise AssertionError('this update is too old.')
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def _check_ocsp_response_signature(response_ocsp, issuer_cert):
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"""Verify an OCSP response signature against certificate issuer"""
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# Following line may raise UnsupportedAlgorithm
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chosen_hash = response_ocsp.signature_hash_algorithm
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crypto_util.verify_signed_payload(issuer_cert.public_key(), response_ocsp.signature,
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response_ocsp.tbs_response_bytes, chosen_hash)
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"""
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try:
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url, _err = util.run_script(
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["openssl", "x509", "-in", cert_path, "-noout", "-ocsp_uri"],
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log=logger.debug)
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except errors.SubprocessError:
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logger.info("Cannot extract OCSP URI from %s", cert_path)
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return None, None
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url = url.rstrip()
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host = url.partition("://")[2].rstrip("/")
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if host:
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return url, host
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else:
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logger.info("Cannot process OCSP host from URL (%s) in cert at %s", url, cert_path)
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return None, None
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def _translate_ocsp_query(cert_path, ocsp_output, ocsp_errors):
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"""Parse openssl's weird output to work out what it means."""
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@@ -212,7 +102,7 @@ def _translate_ocsp_query(cert_path, ocsp_output, ocsp_errors):
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warning = good.group(1) if good else None
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if ("Response verify OK" not in ocsp_errors) or (good and warning) or unknown:
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if (not "Response verify OK" in ocsp_errors) or (good and warning) or unknown:
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logger.info("Revocation status for %s is unknown", cert_path)
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logger.debug("Uncertain output:\n%s\nstderr:\n%s", ocsp_output, ocsp_errors)
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return False
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@@ -225,5 +115,6 @@ def _translate_ocsp_query(cert_path, ocsp_output, ocsp_errors):
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return True
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else:
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logger.warning("Unable to properly parse OCSP output: %s\nstderr:%s",
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ocsp_output, ocsp_errors)
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ocsp_output, ocsp_errors)
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return False
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