def check_twofactor_active(configuration, client_id, user_addr, environ):
"""Check active twofactor session for user with identity. Looks up any
corresponding session cookies and extracts the session_id. In case a
matching session_id state file exists it is read and verified to belong to
the user and still not be expired.
The user_addr argument is used to make sure an active twofactor session
exists from that particular address. It can be set to None to disable the
address check and allow users to change network as long as they have an
active 2FA session.
"""
_logger = configuration.logger
if configuration.site_enable_gdp:
client_id = get_base_client_id(configuration,
client_id,
expand_oid_alias=False)
session_id = client_twofactor_session(configuration, client_id, environ)
if not session_id:
_logger.warning("no 2FA session found for %s" % client_id)
return False
session_data = active_twofactor_session(configuration, client_id,
user_addr)
if session_data is None:
_logger.debug("No active 2FA session for %s (%s)" %
(client_id, user_addr))
return False
else:
_logger.debug("2FA session for %s (%s) is valid: %s" %
(client_id, user_addr, session_data))
return True
def list_twofactor_sessions(configuration, client_id, user_addr=None):
"""List all twofactor sessions for client_id. Optionally filter with client
source.
"""
_logger = configuration.logger
if configuration.site_enable_gdp:
client_id = get_base_client_id(configuration,
client_id,
expand_oid_alias=False)
sessions = {}
client_prefix = generate_session_prefix(configuration, client_id)
pattern = os.path.join(configuration.twofactor_home, client_prefix + '*')
for session_path in glob.glob(pattern):
session_key = os.path.basename(session_path)
session_data = load_twofactor_session(configuration, session_key)
if session_data.get('client_id', None) != client_id:
_logger.debug("skip session %s without user match for %s" %
(session_data, client_id))
continue
elif user_addr and session_data.get('user_addr', None) != user_addr:
_logger.debug("skip session %s without address match for %s (%s)" %
(session_data, client_id, user_addr))
continue
sessions[session_key] = session_data
_logger.debug("found sessions for %s: %s" % (client_id, sessions.keys()))
return sessions
def generate_session_prefix(configuration, client_id):
"""Generate a session prefix with a hash of client_id"""
if configuration.site_enable_gdp:
client_id = get_base_client_id(configuration,
client_id,
expand_oid_alias=False)
return hashlib.sha256(client_id).hexdigest()
def save_twofactor_session(configuration,
client_id,
session_key,
user_addr,
user_agent,
session_start,
session_end=-1):
"""Save twofactor session dict for client_id"""
_logger = configuration.logger
if configuration.site_enable_gdp:
client_id = get_base_client_id(configuration,
client_id,
expand_oid_alias=False)
session_path = os.path.join(configuration.twofactor_home, session_key)
if session_end < 0:
session_end = session_start + twofactor_cookie_ttl
session_data = {
'client_id': client_id,
'session_key': session_key,
'user_addr': user_addr,
'user_agent': user_agent,
'session_start': session_start,
'session_end': session_end
}
status = pickle(session_data, session_path, configuration.logger)
if status and configuration.site_twofactor_strict_address:
session_path_link = os.path.join(configuration.twofactor_home,
"%s_%s" % (user_addr, session_key))
status = \
make_symlink(session_key, session_path_link, _logger, force=False)
if not status:
delete_file(session_path, _logger)
return status
def generate_session_key(configuration, client_id):
"""Generate a random session key with a hash of user id as prefix so that
it is easy to locate all sessions belonging to a particular user.
"""
if configuration.site_enable_gdp:
client_id = get_base_client_id(configuration,
client_id,
expand_oid_alias=False)
session_key = generate_session_prefix(configuration, client_id)
random_key = os.urandom(twofactor_cookie_bytes)
session_key += re.sub(r'[=+/]+', '', base64.b64encode(random_key))
return session_key
def client_twofactor_session(configuration, client_id, environ):
"""Extract any active twofactor session ID from client cookie"""
_logger = configuration.logger
if configuration.site_enable_gdp:
client_id = get_base_client_id(configuration,
client_id,
expand_oid_alias=False)
session_cookie = Cookie.SimpleCookie()
session_cookie.load(environ.get('HTTP_COOKIE', ""))
session_cookie = session_cookie.get('2FA_Auth', None)
if session_cookie is None:
return None
return session_cookie.value
def get_twofactor_token(configuration, client_id, b32_key):
"""Get current twofactor taken for base32 key"""
_logger = configuration.logger
if pyotp is None:
raise Exception("The pyotp module is missing and required for 2FA")
if configuration.site_enable_gdp:
client_id = get_base_client_id(configuration,
client_id,
expand_oid_alias=False)
# IMPORTANT: pyotp unicode breaks when used in our strings - force utf8!
totp = get_totp(client_id, b32_key, configuration)
token = totp.now()
token = force_utf8(token)
return token
def get_twofactor_secrets(configuration, client_id):
"""Load twofactor base32 key and OTP uri for QR code. Generates secret for
user if not already done. Actual twofactor login requirement is not
enabled here, however.
"""
_logger = configuration.logger
if pyotp is None:
raise Exception("The pyotp module is missing and required for 2FA")
if configuration.site_enable_gdp:
client_id = get_base_client_id(configuration,
client_id,
expand_oid_alias=False)
# NOTE: 2FA secret key is a standalone file in user settings dir
# Try to load existing and generate new one if not there.
# We need the base32-encoded form as returned here.
b32_key = load_twofactor_key(client_id, configuration)
if not b32_key:
b32_key = reset_twofactor_key(client_id, configuration)
totp = get_totp(client_id, b32_key, configuration)
# URI-format for otp auth is
# otpauth://<otptype>/(<issuer>:)<accountnospaces>?
# secret=<secret>(&issuer=<issuer>)(&image=<imageuri>)
# which we pull out of pyotp directly.
# IMPORTANT: we use the QRious JS library to keep rendering local.
if configuration.user_openid_alias:
username = extract_field(client_id, configuration.user_openid_alias)
else:
username = client_id
otp_uri = totp.provisioning_uri(username,
issuer_name=configuration.short_title)
# Some auth apps like FreeOTP support addition of logo with &image=PNG_URL
# Testing is easy with https://freeotp.github.io/qrcode.html
if configuration.site_logo_left.endswith('.png'):
logo_url = configuration.site_logo_left
# NOTE: image URL must a full URL and logo_url is abs or anchored path
if not logo_url.startswith('http'):
# Remove any leading slashes which would break join
logo_url = os.path.join(configuration.migserver_https_sid_url,
logo_url.lstrip('/'))
# Clear 'safe' argument to also encode slashes in url
otp_uri += '&image=%s' % urllib.quote(logo_url, '')
# IMPORTANT: pyotp unicode breaks wsgi when inserted - force utf8!
otp_uri = force_utf8(otp_uri)
return (b32_key, totp.interval, otp_uri)
def reset_twofactor_key(client_id, configuration, seed=None, interval=None):
"""Reset 2FA secret key and write to user settings file in scrambled form.
Return the new secret key on unscrambled base32 form.
"""
_logger = configuration.logger
if configuration.site_enable_gdp:
client_id = get_base_client_id(configuration,
client_id,
expand_oid_alias=False)
client_dir = client_id_dir(client_id)
key_path = os.path.join(configuration.user_settings, client_dir,
twofactor_key_name)
try:
if pyotp is None:
raise Exception("The pyotp module is missing and required for 2FA")
if not seed:
b32_key = pyotp.random_base32(length=twofactor_key_bytes)
else:
b32_key = seed
# NOTE: pyotp.random_base32 returns unicode
# which causes trouble with WSGI
b32_key = force_utf8(b32_key)
scrambled = scramble_password(configuration.site_password_salt,
b32_key)
key_fd = open(key_path, 'w')
key_fd.write(scrambled)
key_fd.close()
# Reset interval
interval_path = os.path.join(configuration.user_settings, client_dir,
twofactor_interval_name)
delete_file(interval_path, _logger, allow_missing=True)
if interval:
i_fd = open(interval_path, 'w')
i_fd.write("%d" % interval)
i_fd.close()
except Exception as exc:
_logger.error("failed in reset 2FA key: %s" % exc)
return False
return b32_key
def load_twofactor_interval(client_id, configuration):
"""Load 2FA token interval"""
_logger = configuration.logger
if configuration.site_enable_gdp:
client_id = get_base_client_id(configuration,
client_id,
expand_oid_alias=False)
client_dir = client_id_dir(client_id)
interval_path = os.path.join(configuration.user_settings, client_dir,
twofactor_interval_name)
result = None
if os.path.isfile(interval_path):
i_fd = open(interval_path)
interval = i_fd.read().strip()
i_fd.close()
try:
result = int(interval)
except Exception as exc:
result = None
_logger.error("Failed to read twofactor interval: %s" % exc)
return result
def active_twofactor_session(configuration, client_id, user_addr=None):
"""Load (latest) active twofactor session dict for client_id if any.
Optionally filter to only target sessions originating from user_addr.
"""
_logger = configuration.logger
if configuration.site_enable_gdp:
client_id = get_base_client_id(configuration,
client_id,
expand_oid_alias=False)
# _logger.debug("client_id: '%s', %s" % (client_id, user_addr))
sessions = list_twofactor_sessions(configuration, client_id, user_addr)
latest = None
now = time.time()
for session_data in sessions.values():
# Already checked client_id and optional user_addr match in list
if session_data.get('session_end', -1) < now:
_logger.debug("skip expired session %s (%s)" % (session_data, now))
continue
elif latest is None or latest.get('session_end', -1) < \
session_data.get('session_end', -1):
latest = session_data
_logger.debug("latest session for %s is %s" % (client_id, latest))
return latest
def load_twofactor_key(client_id, configuration, allow_missing=True):
"""Load 2FA secret key on scrambled form from user settings file and
return the unscrambled form.
"""
_logger = configuration.logger
if configuration.site_enable_gdp:
client_id = get_base_client_id(configuration,
client_id,
expand_oid_alias=False)
client_dir = client_id_dir(client_id)
key_path = os.path.join(configuration.user_settings, client_dir,
twofactor_key_name)
b32_key = None
try:
pw_fd = open(key_path)
scrambled = pw_fd.read().strip()
pw_fd.close()
b32_key = unscramble_password(configuration.site_password_salt,
scrambled)
except Exception as exc:
if not allow_missing:
_logger.error("load 2FA key failed: %s" % exc)
return b32_key
def verify_twofactor_token(configuration, client_id, b32_key, token):
"""Verify that supplied token matches the current token for base32 key"""
_logger = configuration.logger
if pyotp is None:
raise Exception("The pyotp module is missing and required for 2FA")
if configuration.site_enable_gdp:
client_id = get_base_client_id(configuration,
client_id,
expand_oid_alias=False)
totp = get_totp(client_id, b32_key, configuration)
valid_token = totp.verify(token, valid_window=valid_otp_window)
if not valid_token \
and hasattr(totp, 'custom_interval') \
and totp.custom_interval:
# Fall back to default interval,
# some App's like Android Google Authenticator
# does not support non-default intervals
totp = get_totp(client_id,
b32_key,
configuration,
force_default_interval=True)
valid_token = totp.verify(token, valid_window=valid_otp_window)
return valid_token
def expire_twofactor_session(configuration,
client_id,
environ,
allow_missing=False,
user_addr=None,
not_user_addr=None):
"""Expire active twofactor session for user with client_id. Looks up any
corresponding session cookie and extracts the session_id. In case a
matching session_id state file exists it is deleted after checking that it
does indeed originate from the client_id.
The optional user_addr argument is used to only expire the active session
from a particular source address for client_id. Left to None in gdp mode to
expire all sessions and make sure only one session is ever active at a time.
The optional not_user_addr argument is used to expire all sessions NOT
from a particular source address for client_id.
"""
_logger = configuration.logger
if configuration.site_enable_gdp:
client_id = get_base_client_id(configuration,
client_id,
expand_oid_alias=False)
session_id = client_twofactor_session(configuration, client_id, environ)
if not session_id:
_logger.warning("no valid 2FA session found for %s" % client_id)
if allow_missing:
return True
return False
# Expire all client_id session files matching user_addr
sessions = list_twofactor_sessions(configuration, client_id, user_addr)
if not sessions:
if allow_missing:
_logger.info("No active 2FA session for %s (%s)" %
(client_id, user_addr))
return True
else:
_logger.error("no 2FA session to expire for %s (%s)" %
(client_id, user_addr))
return False
expired = True
for (session_key, session_data) in sessions.items():
if not_user_addr and session_data.get('user_addr', '') \
== not_user_addr:
continue
session_path = os.path.join(configuration.twofactor_home, session_key)
# Already checked client_id and optionally user_addr match
delete_status = True
if configuration.site_twofactor_strict_address:
session_user_addr = session_data.get('user_addr', None)
if session_user_addr is None:
delete_status = False
else:
session_link_path = \
os.path.join(configuration.twofactor_home, "%s_%s"
% (session_user_addr, session_key))
delete_status = delete_symlink(session_link_path,
_logger,
allow_missing=allow_missing)
if delete_status:
delete_status = delete_file(session_path,
_logger,
allow_missing=allow_missing)
if delete_status:
_logger.info("expired 2FA session %s for %s in %s" %
(session_data, client_id, session_path))
else:
_logger.error("failed to delete 2FA session file %s for %s in %s" %
(session_path, client_id, session_path))
expired = False
return expired
