77ed0d4d0c
Previously, there were a string of commits to keystone that addresed ignored hacking checks. This commit does the same for H405 in keystoneclient. This also modifies our tox.ini so that we no longer ignore H405 violations. Change-Id: I2af152e5425a0e9c82314039fdbb90d661c22680 Closes-Bug: 1482773
429 lines
15 KiB
Python
429 lines
15 KiB
Python
# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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"""Certificate signing functions.
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Call set_subprocess() with the subprocess module. Either Python's
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subprocess or eventlet.green.subprocess can be used.
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If set_subprocess() is not called, this module will pick Python's subprocess
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or eventlet.green.subprocess based on if os module is patched by eventlet.
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"""
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import base64
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import errno
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import hashlib
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import logging
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import zlib
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from debtcollector import removals
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import six
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from keystoneclient import exceptions
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from keystoneclient.i18n import _, _LE
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subprocess = None
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LOG = logging.getLogger(__name__)
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PKI_ASN1_PREFIX = 'MII'
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PKIZ_PREFIX = 'PKIZ_'
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PKIZ_CMS_FORM = 'DER'
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PKI_ASN1_FORM = 'PEM'
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DEFAULT_TOKEN_DIGEST_ALGORITHM = 'sha256'
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# The openssl cms command exits with these status codes.
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# See https://www.openssl.org/docs/apps/cms.html#EXIT_CODES
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class OpensslCmsExitStatus(object):
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SUCCESS = 0
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INPUT_FILE_READ_ERROR = 2
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CREATE_CMS_READ_MIME_ERROR = 3
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def _ensure_subprocess():
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# NOTE(vish): late loading subprocess so we can
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# use the green version if we are in
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# eventlet.
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global subprocess
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if not subprocess:
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try:
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from eventlet import patcher
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if patcher.already_patched:
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from eventlet.green import subprocess
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else:
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import subprocess
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except ImportError:
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import subprocess # noqa
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def set_subprocess(_subprocess=None):
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"""Set subprocess module to use.
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The subprocess could be eventlet.green.subprocess if using eventlet,
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or Python's subprocess otherwise.
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"""
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global subprocess
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subprocess = _subprocess
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def _check_files_accessible(files):
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err = None
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retcode = -1
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try:
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for try_file in files:
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with open(try_file, 'r'):
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pass
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except IOError as e:
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# Catching IOError means there is an issue with
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# the given file.
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err = try_file, e.strerror
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# Emulate openssl behavior, which returns with code 2 when
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# access to a file failed.
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retcode = OpensslCmsExitStatus.INPUT_FILE_READ_ERROR
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return retcode, err
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def _process_communicate_handle_oserror(process, data, files):
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"""Wrapper around process.communicate that checks for OSError."""
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try:
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output, err = process.communicate(data)
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except OSError as e:
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if e.errno != errno.EPIPE:
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raise
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# OSError with EPIPE only occurs with old Python 2.7.x versions
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# http://bugs.python.org/issue10963
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# The quick exit is typically caused by the openssl command not being
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# able to read an input file, so check ourselves if can't read a file.
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retcode, err = _check_files_accessible(files)
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if process.stderr:
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msg = process.stderr.read()
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if isinstance(msg, six.binary_type):
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msg = msg.decode('utf-8')
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if err:
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err = (_('Hit OSError in '
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'_process_communicate_handle_oserror(): '
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'%(stderr)s\nLikely due to %(file)s: %(error)s') %
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{'stderr': msg,
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'file': err[0],
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'error': err[1]})
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else:
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err = (_('Hit OSError in '
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'_process_communicate_handle_oserror(): %s') % msg)
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output = ''
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else:
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retcode = process.poll()
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if err is not None:
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if isinstance(err, six.binary_type):
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err = err.decode('utf-8')
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return output, err, retcode
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def _encoding_for_form(inform):
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if inform == PKI_ASN1_FORM:
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encoding = 'UTF-8'
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elif inform == PKIZ_CMS_FORM:
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encoding = 'hex'
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else:
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raise ValueError(
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_('"inform" must be one of: %s') % ','.join((PKI_ASN1_FORM,
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PKIZ_CMS_FORM)))
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return encoding
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def cms_verify(formatted, signing_cert_file_name, ca_file_name,
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inform=PKI_ASN1_FORM):
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"""Verifies the signature of the contents IAW CMS syntax.
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:raises subprocess.CalledProcessError:
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:raises keystoneclient.exceptions.CertificateConfigError: if certificate
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is not configured
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properly.
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"""
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_ensure_subprocess()
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if isinstance(formatted, six.string_types):
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data = bytearray(formatted, _encoding_for_form(inform))
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else:
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data = formatted
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process = subprocess.Popen(['openssl', 'cms', '-verify',
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'-certfile', signing_cert_file_name,
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'-CAfile', ca_file_name,
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'-inform', 'PEM',
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'-nosmimecap', '-nodetach',
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'-nocerts', '-noattr'],
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stdin=subprocess.PIPE,
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stdout=subprocess.PIPE,
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stderr=subprocess.PIPE,
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close_fds=True)
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output, err, retcode = _process_communicate_handle_oserror(
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process, data, (signing_cert_file_name, ca_file_name))
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# Do not log errors, as some happen in the positive thread
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# instead, catch them in the calling code and log them there.
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# When invoke the openssl with not exist file, return code 2
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# and error msg will be returned.
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# You can get more from
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# http://www.openssl.org/docs/apps/cms.html#EXIT_CODES
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#
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# $ openssl cms -verify -certfile not_exist_file -CAfile
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# not_exist_file -inform PEM -nosmimecap -nodetach
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# -nocerts -noattr
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# Error opening certificate file not_exist_file
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#
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if retcode == OpensslCmsExitStatus.INPUT_FILE_READ_ERROR:
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if err.startswith('Error reading S/MIME message'):
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raise exceptions.CMSError(err)
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else:
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raise exceptions.CertificateConfigError(err)
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elif retcode != OpensslCmsExitStatus.SUCCESS:
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raise subprocess.CalledProcessError(retcode, 'openssl', output=err)
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return output
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def is_pkiz(token_text):
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"""Determine if a token a cmsz token
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Checks if the string has the prefix that indicates it is a
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Crypto Message Syntax, Z compressed token.
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"""
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return token_text.startswith(PKIZ_PREFIX)
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def pkiz_sign(text,
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signing_cert_file_name,
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signing_key_file_name,
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compression_level=6,
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message_digest=DEFAULT_TOKEN_DIGEST_ALGORITHM):
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signed = cms_sign_data(text,
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signing_cert_file_name,
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signing_key_file_name,
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PKIZ_CMS_FORM,
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message_digest=message_digest)
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compressed = zlib.compress(signed, compression_level)
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encoded = PKIZ_PREFIX + base64.urlsafe_b64encode(
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compressed).decode('utf-8')
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return encoded
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def pkiz_uncompress(signed_text):
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text = signed_text[len(PKIZ_PREFIX):].encode('utf-8')
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unencoded = base64.urlsafe_b64decode(text)
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uncompressed = zlib.decompress(unencoded)
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return uncompressed
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def pkiz_verify(signed_text, signing_cert_file_name, ca_file_name):
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uncompressed = pkiz_uncompress(signed_text)
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return cms_verify(uncompressed, signing_cert_file_name, ca_file_name,
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inform=PKIZ_CMS_FORM)
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def token_to_cms(signed_text):
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"""Converts a custom formatted token to a PEM-formatted token.
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See documentation for cms_to_token() for details on the custom formatting.
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"""
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copy_of_text = signed_text.replace('-', '/')
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lines = ['-----BEGIN CMS-----']
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lines += [copy_of_text[n:n + 64] for n in range(0, len(copy_of_text), 64)]
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lines.append('-----END CMS-----\n')
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return '\n'.join(lines)
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def verify_token(token, signing_cert_file_name, ca_file_name):
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return cms_verify(token_to_cms(token),
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signing_cert_file_name,
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ca_file_name)
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def is_asn1_token(token):
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"""Determine if a token appears to be PKI-based.
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thx to ayoung for sorting this out.
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base64 decoded hex representation of MII is 3082::
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In [3]: binascii.hexlify(base64.b64decode('MII='))
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Out[3]: '3082'
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re: http://www.itu.int/ITU-T/studygroups/com17/languages/X.690-0207.pdf
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::
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pg4: For tags from 0 to 30 the first octet is the identfier
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pg10: Hex 30 means sequence, followed by the length of that sequence.
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pg5: Second octet is the length octet
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first bit indicates short or long form, next 7 bits encode the
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number of subsequent octets that make up the content length octets
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as an unsigned binary int
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82 = 10000010 (first bit indicates long form)
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0000010 = 2 octets of content length
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so read the next 2 octets to get the length of the content.
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In the case of a very large content length there could be a requirement to
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have more than 2 octets to designate the content length, therefore
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requiring us to check for MIM, MIQ, etc.
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::
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In [4]: base64.b64encode(binascii.a2b_hex('3083'))
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Out[4]: 'MIM='
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In [5]: base64.b64encode(binascii.a2b_hex('3084'))
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Out[5]: 'MIQ='
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Checking for MI would become invalid at 16 octets of content length
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10010000 = 90
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In [6]: base64.b64encode(binascii.a2b_hex('3090'))
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Out[6]: 'MJA='
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Checking for just M is insufficient
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But we will only check for MII:
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Max length of the content using 2 octets is 3FFF or 16383.
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It's not practical to support a token of this length or greater in http
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therefore, we will check for MII only and ignore the case of larger tokens
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"""
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return token[:3] == PKI_ASN1_PREFIX
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@removals.remove(message='Use is_asn1_token() instead.', version='1.7.0',
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removal_version='2.0.0')
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def is_ans1_token(token):
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"""Deprecated.
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This function is deprecated as of the 1.7.0 release in favor of
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:func:`is_asn1_token` and may be removed in the 2.0.0 release.
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"""
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return is_asn1_token(token)
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def cms_sign_text(data_to_sign, signing_cert_file_name, signing_key_file_name,
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message_digest=DEFAULT_TOKEN_DIGEST_ALGORITHM):
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return cms_sign_data(data_to_sign, signing_cert_file_name,
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signing_key_file_name, message_digest=message_digest)
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def cms_sign_data(data_to_sign, signing_cert_file_name, signing_key_file_name,
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outform=PKI_ASN1_FORM,
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message_digest=DEFAULT_TOKEN_DIGEST_ALGORITHM):
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"""Uses OpenSSL to sign a document.
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Produces a Base64 encoding of a DER formatted CMS Document
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http://en.wikipedia.org/wiki/Cryptographic_Message_Syntax
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:param data_to_sign: data to sign
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:param signing_cert_file_name: path to the X509 certificate containing
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the public key associated with the private key used to sign the data
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:param signing_key_file_name: path to the private key used to sign
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the data
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:param outform: Format for the signed document PKIZ_CMS_FORM or
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PKI_ASN1_FORM
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:param message_digest: Digest algorithm to use when signing or resigning
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"""
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_ensure_subprocess()
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if isinstance(data_to_sign, six.string_types):
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data = bytearray(data_to_sign, encoding='utf-8')
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else:
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data = data_to_sign
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process = subprocess.Popen(['openssl', 'cms', '-sign',
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'-signer', signing_cert_file_name,
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'-inkey', signing_key_file_name,
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'-outform', 'PEM',
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'-nosmimecap', '-nodetach',
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'-nocerts', '-noattr',
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'-md', message_digest, ],
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stdin=subprocess.PIPE,
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stdout=subprocess.PIPE,
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stderr=subprocess.PIPE,
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close_fds=True)
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output, err, retcode = _process_communicate_handle_oserror(
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process, data, (signing_cert_file_name, signing_key_file_name))
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if retcode != OpensslCmsExitStatus.SUCCESS or ('Error' in err):
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if retcode == OpensslCmsExitStatus.CREATE_CMS_READ_MIME_ERROR:
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LOG.error(_LE('Signing error: Unable to load certificate - '
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'ensure you have configured PKI with '
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'"keystone-manage pki_setup"'))
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else:
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LOG.error(_LE('Signing error: %s'), err)
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raise subprocess.CalledProcessError(retcode, 'openssl')
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if outform == PKI_ASN1_FORM:
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return output.decode('utf-8')
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else:
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return output
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def cms_sign_token(text, signing_cert_file_name, signing_key_file_name,
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message_digest=DEFAULT_TOKEN_DIGEST_ALGORITHM):
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output = cms_sign_data(text, signing_cert_file_name, signing_key_file_name,
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message_digest=message_digest)
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return cms_to_token(output)
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def cms_to_token(cms_text):
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"""Converts a CMS-signed token in PEM format to a custom URL-safe format.
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The conversion consists of replacing '/' char in the PEM-formatted token
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with the '-' char and doing other such textual replacements to make the
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result marshallable via HTTP. The return value can thus be used as the
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value of a HTTP header such as "X-Auth-Token".
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This ad-hoc conversion is an unfortunate oversight since the returned
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value now does not conform to any of the standard variants of base64
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encoding. It would have been better to use base64url encoding (either on
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the PEM formatted text or, perhaps even better, on the inner CMS-signed
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binary value without any PEM formatting). In any case, the same conversion
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is done in reverse in the other direction (for token verification), so
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there are no correctness issues here. Note that the non-standard encoding
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of the token will be preserved so as to not break backward compatibility.
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The conversion issue is detailed by the code author in a blog post at
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http://adam.younglogic.com/2014/02/compressed-tokens/.
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"""
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start_delim = '-----BEGIN CMS-----'
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end_delim = '-----END CMS-----'
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signed_text = cms_text
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signed_text = signed_text.replace('/', '-')
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signed_text = signed_text.replace(start_delim, '')
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signed_text = signed_text.replace(end_delim, '')
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signed_text = signed_text.replace('\n', '')
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return signed_text
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def cms_hash_token(token_id, mode='md5'):
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"""Hash PKI tokens.
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return: for asn1 or pkiz tokens, returns the hash of the passed in token
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otherwise, returns what it was passed in.
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"""
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if token_id is None:
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return None
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if is_asn1_token(token_id) or is_pkiz(token_id):
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hasher = hashlib.new(mode)
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if isinstance(token_id, six.text_type):
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token_id = token_id.encode('utf-8')
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hasher.update(token_id)
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return hasher.hexdigest()
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else:
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return token_id
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