freeipa/ipapython/certdb.py
Petr Viktorin 099cf98307 Refactor ipautil.run
The ipautil.run function now returns an object with returncode and
output are accessible as attributes.

The stdout and stderr of all commands are logged (unless skip_output is given).

The stdout/stderr contents must be explicitly requested with a keyword
argument, otherwise they are None.
This is because in Python 3, the output needs to be decoded, and that can
fail if it's not decodable (human-readable) text.

The raw (bytes) output is always available from the result object,
as is "leniently" decoded output suitable for logging.

All calls are changed to reflect this.

A use of Popen in cainstance is changed to ipautil.run.

Reviewed-By: Jan Cholasta <jcholast@redhat.com>
2015-12-14 10:54:23 +01:00

520 lines
19 KiB
Python

# Authors: Rob Crittenden <rcritten@redhat.com>
#
# Copyright (C) 2009 Red Hat
# see file 'COPYING' for use and warranty information
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
#
import os
import re
import tempfile
import shutil
import base64
from nss import nss
from nss.error import NSPRError
from ipaplatform.paths import paths
from ipapython.ipa_log_manager import root_logger
from ipapython import ipautil
from ipalib import x509
CA_NICKNAME_FMT = "%s IPA CA"
def get_ca_nickname(realm, format=CA_NICKNAME_FMT):
return format % realm
def create_ipa_nssdb():
db = NSSDatabase(paths.IPA_NSSDB_DIR)
pwdfile = os.path.join(db.secdir, 'pwdfile.txt')
ipautil.backup_file(pwdfile)
ipautil.backup_file(os.path.join(db.secdir, 'cert8.db'))
ipautil.backup_file(os.path.join(db.secdir, 'key3.db'))
ipautil.backup_file(os.path.join(db.secdir, 'secmod.db'))
with open(pwdfile, 'w') as f:
f.write(ipautil.ipa_generate_password(pwd_len=40))
os.chmod(pwdfile, 0o600)
db.create_db(pwdfile)
os.chmod(os.path.join(db.secdir, 'cert8.db'), 0o644)
os.chmod(os.path.join(db.secdir, 'key3.db'), 0o644)
os.chmod(os.path.join(db.secdir, 'secmod.db'), 0o644)
def find_cert_from_txt(cert, start=0):
"""
Given a cert blob (str) which may or may not contian leading and
trailing text, pull out just the certificate part. This will return
the FIRST cert in a stream of data.
Returns a tuple (certificate, last position in cert)
"""
s = cert.find('-----BEGIN CERTIFICATE-----', start)
e = cert.find('-----END CERTIFICATE-----', s)
if e > 0:
e = e + 25
if s < 0 or e < 0:
raise RuntimeError("Unable to find certificate")
cert = cert[s:e]
return (cert, e)
class NSSDatabase(object):
"""A general-purpose wrapper around a NSS cert database
For permanent NSS databases, pass the cert DB directory to __init__
For temporary databases, do not pass nssdir, and call close() when done
to remove the DB. Alternatively, a NSSDatabase can be used as a
context manager that calls close() automatically.
"""
# Traditionally, we used CertDB for our NSS DB operations, but that class
# got too tied to IPA server details, killing reusability.
# BaseCertDB is a class that knows nothing about IPA.
# Generic NSS DB code should be moved here.
def __init__(self, nssdir=None):
if nssdir is None:
self.secdir = tempfile.mkdtemp()
self._is_temporary = True
else:
self.secdir = nssdir
self._is_temporary = False
def close(self):
if self._is_temporary:
shutil.rmtree(self.secdir)
def __enter__(self):
return self
def __exit__(self, type, value, tb):
self.close()
def run_certutil(self, args, stdin=None, **kwargs):
new_args = [paths.CERTUTIL, "-d", self.secdir]
new_args = new_args + args
return ipautil.run(new_args, stdin, **kwargs)
def create_db(self, password_filename):
"""Create cert DB
:param password_filename: Name of file containing the database password
"""
self.run_certutil(["-N", "-f", password_filename])
def list_certs(self):
"""Return nicknames and cert flags for all certs in the database
:return: List of (name, trust_flags) tuples
"""
result = self.run_certutil(["-L"], capture_output=True)
certs = result.output.splitlines()
# FIXME, this relies on NSS never changing the formatting of certutil
certlist = []
for cert in certs:
match = re.match(r'^(.+?)\s+(\w*,\w*,\w*)\s*$', cert)
if match:
certlist.append(match.groups())
return tuple(certlist)
def find_server_certs(self):
"""Return nicknames and cert flags for server certs in the database
Server certs have an "u" character in the trust flags.
:return: List of (name, trust_flags) tuples
"""
server_certs = []
for name, flags in self.list_certs():
if 'u' in flags:
server_certs.append((name, flags))
return server_certs
def get_trust_chain(self, nickname):
"""Return names of certs in a given cert's trust chain
:param nickname: Name of the cert
:return: List of certificate names
"""
root_nicknames = []
result = self.run_certutil(["-O", "-n", nickname], capture_output=True)
chain = result.output.splitlines()
for c in chain:
m = re.match('\s*"(.*)" \[.*', c)
if m:
root_nicknames.append(m.groups()[0])
return root_nicknames
def import_pkcs12(self, pkcs12_filename, db_password_filename,
pkcs12_passwd=None):
args = [paths.PK12UTIL, "-d", self.secdir,
"-i", pkcs12_filename,
"-k", db_password_filename, '-v']
if pkcs12_passwd is not None:
pkcs12_passwd = pkcs12_passwd + '\n'
args = args + ["-w", paths.DEV_STDIN]
try:
ipautil.run(args, stdin=pkcs12_passwd)
except ipautil.CalledProcessError as e:
if e.returncode == 17:
raise RuntimeError("incorrect password for pkcs#12 file %s" %
pkcs12_filename)
elif e.returncode == 10:
raise RuntimeError("Failed to open %s" % pkcs12_filename)
else:
raise RuntimeError("unknown error import pkcs#12 file %s" %
pkcs12_filename)
def import_files(self, files, db_password_filename, import_keys=False,
key_password=None, key_nickname=None):
"""
Import certificates and a single private key from multiple files
The files may be in PEM and DER certificate, PKCS#7 certificate chain,
PKCS#8 and raw private key and PKCS#12 formats.
:param files: Names of files to import
:param db_password_filename: Name of file containing the database
password
:param import_keys: Whether to import private keys
:param key_password: Password to decrypt private keys
:param key_nickname: Nickname of the private key to import from PKCS#12
files
"""
key_file = None
extracted_key = None
extracted_certs = ''
for filename in files:
try:
with open(filename, 'rb') as f:
data = f.read()
except IOError as e:
raise RuntimeError(
"Failed to open %s: %s" % (filename, e.strerror))
# Try to parse the file as PEM file
matches = list(re.finditer(
r'-----BEGIN (.+?)-----(.*?)-----END \1-----', data, re.DOTALL))
if matches:
loaded = False
for match in matches:
body = match.group()
label = match.group(1)
line = len(data[:match.start() + 1].splitlines())
if label in ('CERTIFICATE', 'X509 CERTIFICATE',
'X.509 CERTIFICATE'):
try:
x509.load_certificate(match.group(2))
except NSPRError as e:
if label != 'CERTIFICATE':
root_logger.warning(
"Skipping certificate in %s at line %s: %s",
filename, line, e)
continue
else:
extracted_certs += body + '\n'
loaded = True
continue
if label in ('PKCS7', 'PKCS #7 SIGNED DATA', 'CERTIFICATE'):
args = [
paths.OPENSSL, 'pkcs7',
'-print_certs',
]
try:
result = ipautil.run(
args, stdin=body, capture_output=True)
except ipautil.CalledProcessError as e:
if label == 'CERTIFICATE':
root_logger.warning(
"Skipping certificate in %s at line %s: %s",
filename, line, e)
else:
root_logger.warning(
"Skipping PKCS#7 in %s at line %s: %s",
filename, line, e)
continue
else:
extracted_certs += result.output + '\n'
loaded = True
continue
if label in ('PRIVATE KEY', 'ENCRYPTED PRIVATE KEY',
'RSA PRIVATE KEY', 'DSA PRIVATE KEY',
'EC PRIVATE KEY'):
if not import_keys:
continue
if key_file:
raise RuntimeError(
"Can't load private key from both %s and %s" %
(key_file, filename))
args = [
paths.OPENSSL, 'pkcs8',
'-topk8',
'-passout', 'file:' + db_password_filename,
]
if ((label != 'PRIVATE KEY' and key_password) or
label == 'ENCRYPTED PRIVATE KEY'):
key_pwdfile = ipautil.write_tmp_file(key_password)
args += [
'-passin', 'file:' + key_pwdfile.name,
]
try:
result = ipautil.run(
args, stdin=body, capture_output=True)
except ipautil.CalledProcessError as e:
root_logger.warning(
"Skipping private key in %s at line %s: %s",
filename, line, e)
continue
else:
extracted_key = result.output
key_file = filename
loaded = True
continue
if loaded:
continue
raise RuntimeError("Failed to load %s" % filename)
# Try to load the file as DER certificate
try:
x509.load_certificate(data, x509.DER)
except NSPRError:
pass
else:
data = x509.make_pem(base64.b64encode(data))
extracted_certs += data + '\n'
continue
# Try to import the file as PKCS#12 file
if import_keys:
try:
self.import_pkcs12(
filename, db_password_filename, key_password)
except RuntimeError:
pass
else:
if key_file:
raise RuntimeError(
"Can't load private key from both %s and %s" %
(key_file, filename))
key_file = filename
server_certs = self.find_server_certs()
if key_nickname:
for nickname, trust_flags in server_certs:
if nickname == key_nickname:
break
else:
raise RuntimeError(
"Server certificate \"%s\" not found in %s" %
(key_nickname, filename))
else:
if len(server_certs) > 1:
raise RuntimeError(
"%s server certificates found in %s, "
"expecting only one" %
(len(server_certs), filename))
continue
raise RuntimeError("Failed to load %s" % filename)
if import_keys and not key_file:
raise RuntimeError(
"No server certificates found in %s" % (', '.join(files)))
nss_certs = x509.load_certificate_list(extracted_certs)
nss_cert = None
for nss_cert in nss_certs:
nickname = str(nss_cert.subject)
self.add_cert(nss_cert.der_data, nickname, ',,')
del nss_certs, nss_cert
if extracted_key:
in_file = ipautil.write_tmp_file(extracted_certs + extracted_key)
out_file = tempfile.NamedTemporaryFile()
out_password = ipautil.ipa_generate_password()
out_pwdfile = ipautil.write_tmp_file(out_password)
args = [
paths.OPENSSL, 'pkcs12',
'-export',
'-in', in_file.name,
'-out', out_file.name,
'-passin', 'file:' + db_password_filename,
'-passout', 'file:' + out_pwdfile.name,
]
try:
ipautil.run(args)
except ipautil.CalledProcessError as e:
raise RuntimeError(
"No matching certificate found for private key from %s" %
key_file)
self.import_pkcs12(out_file.name, db_password_filename,
out_password)
def trust_root_cert(self, root_nickname, trust_flags=None):
if root_nickname[:7] == "Builtin":
root_logger.debug(
"No need to add trust for built-in root CAs, skipping %s" %
root_nickname)
else:
if trust_flags is None:
trust_flags = 'C,,'
try:
self.run_certutil(["-M", "-n", root_nickname,
"-t", trust_flags])
except ipautil.CalledProcessError as e:
raise RuntimeError(
"Setting trust on %s failed" % root_nickname)
def get_cert(self, nickname, pem=False):
args = ['-L', '-n', nickname]
if pem:
args.append('-a')
else:
args.append('-r')
try:
result = self.run_certutil(args, capture_output=pem)
except ipautil.CalledProcessError:
raise RuntimeError("Failed to get %s" % nickname)
if pem:
return result.output
else:
return result.raw_output
def has_nickname(self, nickname):
try:
self.get_cert(nickname)
except RuntimeError:
# This might be error other than "nickname not found". Beware.
return False
else:
return True
def export_pem_cert(self, nickname, location):
"""Export the given cert to PEM file in the given location"""
cert = self.get_cert(nickname, pem=True)
with open(location, "w+") as fd:
fd.write(cert)
os.chmod(location, 0o444)
def import_pem_cert(self, nickname, flags, location):
"""Import a cert form the given PEM file.
The file must contain exactly one certificate.
"""
try:
with open(location) as fd:
certs = fd.read()
except IOError as e:
raise RuntimeError(
"Failed to open %s: %s" % (location, e.strerror)
)
cert, st = find_cert_from_txt(certs)
self.add_cert(cert, nickname, flags, pem=True)
try:
find_cert_from_txt(certs, st)
except RuntimeError:
pass
else:
raise ValueError('%s contains more than one certificate' %
location)
def add_cert(self, cert, nick, flags, pem=False):
args = ["-A", "-n", nick, "-t", flags]
if pem:
args.append("-a")
self.run_certutil(args, stdin=cert)
def delete_cert(self, nick):
self.run_certutil(["-D", "-n", nick])
def verify_server_cert_validity(self, nickname, hostname):
"""Verify a certificate is valid for a SSL server with given hostname
Raises a ValueError if the certificate is invalid.
"""
certdb = cert = None
if nss.nss_is_initialized():
nss.nss_shutdown()
nss.nss_init(self.secdir)
try:
certdb = nss.get_default_certdb()
cert = nss.find_cert_from_nickname(nickname)
intended_usage = nss.certificateUsageSSLServer
try:
approved_usage = cert.verify_now(certdb, True, intended_usage)
except NSPRError as e:
if e.errno != -8102:
raise ValueError(e.strerror)
approved_usage = 0
if not approved_usage & intended_usage:
raise ValueError('invalid for a SSL server')
if not cert.verify_hostname(hostname):
raise ValueError('invalid for server %s' % hostname)
finally:
del certdb, cert
nss.nss_shutdown()
return None
def verify_ca_cert_validity(self, nickname):
certdb = cert = None
if nss.nss_is_initialized():
nss.nss_shutdown()
nss.nss_init(self.secdir)
try:
certdb = nss.get_default_certdb()
cert = nss.find_cert_from_nickname(nickname)
if not cert.subject:
raise ValueError("has empty subject")
try:
bc = cert.get_extension(nss.SEC_OID_X509_BASIC_CONSTRAINTS)
except KeyError:
raise ValueError("missing basic constraints")
bc = nss.BasicConstraints(bc.value)
if not bc.is_ca:
raise ValueError("not a CA certificate")
intended_usage = nss.certificateUsageSSLCA
try:
approved_usage = cert.verify_now(certdb, True, intended_usage)
except NSPRError as e:
if e.errno != -8102: # SEC_ERROR_INADEQUATE_KEY_USAGE
raise ValueError(e.strerror)
approved_usage = 0
if approved_usage & intended_usage != intended_usage:
raise ValueError('invalid for a CA')
finally:
del certdb, cert
nss.nss_shutdown()