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44a6ec29c5
Some code uses `logging.debug` and `logging.info` instead of the file-specific logger in `logger.debug` and `logger.info`.
120 lines
4.1 KiB
Python
120 lines
4.1 KiB
Python
"""Tools for checking certificate revocation."""
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import logging
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import re
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from subprocess import Popen, PIPE
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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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def __init__(self):
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self.broken = False
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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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def ocsp_revoked(self, cert_path, chain_path):
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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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"""
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if self.broken:
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return False
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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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# 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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"-issuer", chain_path,
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"-cert", cert_path,
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"-url", url,
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"-CAfile", chain_path,
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"-verify_other", chain_path,
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"-trust_other",
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"-header"] + self.host_args(host)
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logger.debug("Querying OCSP for %s", cert_path)
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logger.debug(" ".join(cmd))
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try:
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output, err = util.run_script(cmd, log=logger.debug)
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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(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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"""
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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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states = ("good", "revoked", "unknown")
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patterns = [r"{0}: (WARNING.*)?{1}".format(cert_path, s) for s in states]
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good, revoked, unknown = (re.search(p, ocsp_output, flags=re.DOTALL) for p in patterns)
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warning = good.group(1) if good else None
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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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elif good and not warning:
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return False
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elif revoked:
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warning = revoked.group(1)
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if warning:
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logger.info("OCSP revocation warning: %s", warning)
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return True
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else:
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logger.warn("Unable to properly parse OCSP output: %s\nstderr:%s",
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ocsp_output, ocsp_errors)
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return False
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