283 lines
9.7 KiB
Python
283 lines
9.7 KiB
Python
# This file is part of Gajim.
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#
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# Gajim is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published
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# by the Free Software Foundation; version 3 only.
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#
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# Gajim is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with Gajim. If not, see <http://www.gnu.org/licenses/>.
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import logging
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from pathlib import Path
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from OpenSSL import SSL, crypto
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import nbxmpp
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from nbxmpp.namespaces import Namespace
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from nbxmpp.util import generate_id
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from gajim.common import app
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from gajim.common import configpaths
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log = logging.getLogger('gajim.c.jingle_xtls')
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# key-exchange id -> [callback, args], accept that session once key-exchange completes
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pending_contents = {}
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def key_exchange_pend(id_, cb, args):
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# args is a list
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pending_contents[id_] = [cb, args]
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def approve_pending_content(id_):
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cb = pending_contents[id_][0]
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args = pending_contents[id_][1]
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cb(*args)
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TYPE_RSA = crypto.TYPE_RSA
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TYPE_DSA = crypto.TYPE_DSA
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SELF_SIGNED_CERTIFICATE = 'localcert'
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DH_PARAMS = 'dh_params.pem'
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DEFAULT_DH_PARAMS = 'dh4096.pem'
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def default_callback(connection, certificate, error_num, depth, return_code):
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log.info("certificate: %s", certificate)
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return return_code
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def load_cert_file(cert_path, cert_store=None):
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"""
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This is almost identical to the one in nbxmpp.tls_nb
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"""
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if not cert_path.is_file():
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return None
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try:
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f = open(cert_path)
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except IOError as e:
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log.warning('Unable to open certificate file %s: %s', cert_path,
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str(e))
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return None
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lines = f.readlines()
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i = 0
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begin = -1
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for line in lines:
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if 'BEGIN CERTIFICATE' in line:
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begin = i
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elif 'END CERTIFICATE' in line and begin > -1:
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cert = ''.join(lines[begin:i+2])
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try:
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x509cert = crypto.load_certificate(crypto.FILETYPE_PEM, cert)
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if cert_store:
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cert_store.add_cert(x509cert)
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f.close()
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return x509cert
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except crypto.Error as exception_obj:
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log.warning('Unable to load a certificate from file %s: %s',
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cert_path, exception_obj.args[0][0][2])
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except Exception:
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log.warning('Unknown error while loading certificate from file '
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'%s', cert_path)
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begin = -1
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i += 1
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f.close()
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def get_context(fingerprint, verify_cb=None, remote_jid=None):
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"""
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constructs and returns the context objects
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"""
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ctx = SSL.Context(SSL.SSLv23_METHOD)
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flags = (SSL.OP_NO_SSLv2 | SSL.OP_NO_SSLv3 | SSL.OP_SINGLE_DH_USE \
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| SSL.OP_NO_TICKET)
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ctx.set_options(flags)
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ctx.set_cipher_list(b'HIGH:!aNULL:!3DES')
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if fingerprint == 'server': # for testing purposes only
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ctx.set_verify(SSL.VERIFY_NONE|SSL.VERIFY_FAIL_IF_NO_PEER_CERT,
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verify_cb or default_callback)
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elif fingerprint == 'client':
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ctx.set_verify(SSL.VERIFY_PEER, verify_cb or default_callback)
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cert_name = configpaths.get('MY_CERT') / SELF_SIGNED_CERTIFICATE
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ctx.use_privatekey_file(str(cert_name.with_suffix('.pkey')).encode('utf-8'))
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ctx.use_certificate_file(str(cert_name.with_suffix('.cert')).encode('utf-8'))
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# Try to load Diffie-Hellman parameters.
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# First try user DH parameters, if this fails load the default DH parameters
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dh_params_name = configpaths.get('MY_CERT') / DH_PARAMS
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try:
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with open(dh_params_name, "r"):
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ctx.load_tmp_dh(dh_params_name.encode('utf-8'))
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except FileNotFoundError as err:
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default_dh_params_name = (configpaths.get('DATA') / 'other' /
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DEFAULT_DH_PARAMS)
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try:
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with open(default_dh_params_name, "r"):
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ctx.load_tmp_dh(str(default_dh_params_name).encode('utf-8'))
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except FileNotFoundError as err:
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log.error('Unable to load default DH parameter file: %s, %s',
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default_dh_params_name, err)
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raise
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if remote_jid:
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store = ctx.get_cert_store()
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path = configpaths.get('MY_PEER_CERTS').expanduser() / (remote_jid
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+ '.cert')
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if path.exists():
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load_cert_file(path, cert_store=store)
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log.debug('certificate file %s loaded fingerprint %s',
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path, fingerprint)
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return ctx
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def read_cert(certpath):
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certificate = ''
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with open(certpath, 'r') as certfile:
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for line in certfile.readlines():
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if not line.startswith('-'):
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certificate += line
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return certificate
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def send_cert(con, jid_from, sid):
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certpath = configpaths.get('MY_CERT') / (SELF_SIGNED_CERTIFICATE
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+ '.cert')
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certificate = read_cert(certpath)
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iq = nbxmpp.Iq('result', to=jid_from)
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iq.setAttr('id', sid)
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pubkey = iq.setTag('pubkeys')
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pubkey.setNamespace(Namespace.PUBKEY_PUBKEY)
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keyinfo = pubkey.setTag('keyinfo')
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name = keyinfo.setTag('name')
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name.setData('CertificateHash')
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cert = keyinfo.setTag('x509cert')
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cert.setData(certificate)
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con.send(iq)
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def handle_new_cert(con, obj, jid_from):
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jid = app.get_jid_without_resource(jid_from)
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certpath = configpaths.get('MY_PEER_CERTS').expanduser() / (jid + '.cert')
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id_ = obj.getAttr('id')
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x509cert = obj.getTag('pubkeys').getTag('keyinfo').getTag('x509cert')
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cert = x509cert.getData()
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f = open(certpath, 'w')
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f.write('-----BEGIN CERTIFICATE-----\n')
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f.write(cert)
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f.write('-----END CERTIFICATE-----\n')
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f.close()
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approve_pending_content(id_)
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def check_cert(jid, fingerprint):
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certpath = configpaths.get('MY_PEER_CERTS').expanduser() / (jid + '.cert')
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if certpath.exists():
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cert = load_cert_file(certpath)
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if cert:
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digest_algo = cert.get_signature_algorithm().decode('utf-8')\
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.split('With')[0]
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if cert.digest(digest_algo) == fingerprint:
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return True
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return False
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def send_cert_request(con, to_jid):
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iq = nbxmpp.Iq('get', to=to_jid)
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id_ = generate_id()
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iq.setAttr('id', id_)
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pubkey = iq.setTag('pubkeys')
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pubkey.setNamespace(Namespace.PUBKEY_PUBKEY)
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con.connection.send(iq)
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return str(id_)
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# the following code is partly due to pyopenssl examples
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def createKeyPair(type_, bits):
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"""
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Create a public/private key pair.
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Arguments: type_ - Key type, must be one of TYPE_RSA and TYPE_DSA
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bits - Number of bits to use in the key
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Returns: The public/private key pair in a PKey object
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"""
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pkey = crypto.PKey()
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pkey.generate_key(type_, bits)
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return pkey
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def createCertRequest(pkey, digest="sha256", **name):
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"""
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Create a certificate request.
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Arguments: pkey - The key to associate with the request
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digest - Digestion method to use for signing, default is sha256
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**name - The name of the subject of the request, possible
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arguments are:
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C - Country name
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ST - State or province name
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L - Locality name
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O - Organization name
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OU - Organizational unit name
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CN - Common name
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emailAddress - E-mail address
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Returns: The certificate request in an X509Req object
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"""
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req = crypto.X509Req()
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subj = req.get_subject()
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for (key, value) in name.items():
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setattr(subj, key, value)
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req.set_pubkey(pkey)
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req.sign(pkey, digest)
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return req
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def createCertificate(req, issuerCert, issuerKey, serial, notBefore, notAfter, digest="sha256"):
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"""
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Generate a certificate given a certificate request.
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Arguments: req - Certificate request to use
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issuerCert - The certificate of the issuer
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issuerKey - The private key of the issuer
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serial - Serial number for the certificate
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notBefore - Timestamp (relative to now) when the certificate
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starts being valid
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notAfter - Timestamp (relative to now) when the certificate
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stops being valid
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digest - Digest method to use for signing, default is sha256
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Returns: The signed certificate in an X509 object
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"""
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cert = crypto.X509()
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cert.set_serial_number(serial)
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cert.gmtime_adj_notBefore(notBefore)
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cert.gmtime_adj_notAfter(notAfter)
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cert.set_issuer(issuerCert.get_subject())
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cert.set_subject(req.get_subject())
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cert.set_pubkey(req.get_pubkey())
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cert.sign(issuerKey, digest)
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return cert
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def make_certs(filepath, CN):
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"""
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make self signed certificates
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filepath : absolute path of certificate file, will be appended the '.pkey'
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and '.cert' extensions
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CN : common name
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"""
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key = createKeyPair(TYPE_RSA, 4096)
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req = createCertRequest(key, CN=CN)
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cert = createCertificate(req, req, key, 0, 0, 60*60*24*365*5) # five years
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with open(filepath.with_suffix('.pkey'), 'wb') as f:
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filepath.with_suffix('.pkey').chmod(0o600)
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f.write(crypto.dump_privatekey(crypto.FILETYPE_PEM, key))
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with open(filepath.with_suffix('.cert'), 'wb') as f:
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f.write(crypto.dump_certificate(crypto.FILETYPE_PEM, cert))
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if __name__ == '__main__':
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make_certs(Path('selfcert'), 'gajim')
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