/usr/lib/python3/dist-packages/policyd_rate_limit/policyd.py is in policyd-rate-limit 0.7.1-1.
This file is owned by root:root, with mode 0o644.
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# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE. See the GNU General Public License version 3 for
# more details.
#
# You should have received a copy of the GNU General Public License version 3
# along with this program; if not, write to the Free Software Foundation, Inc., 51
# Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
#
# (c) 2015-2016 Valentin Samir
import os
import sys
import socket
import time
import select
from policyd_rate_limit import utils
from policyd_rate_limit.utils import config
class Pass(Exception):
pass
class Policyd(object):
"""The policy server class"""
socket_data_read = {}
socket_data_write = {}
def socket(self):
"""initialize the socket from the config parameters"""
# if socket is a string assume it is the path to an unix socket
if isinstance(config.SOCKET, str):
try:
os.remove(config.SOCKET)
except OSError:
if os.path.exists(config.SOCKET): # pragma: no cover (should not happen)
raise
sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
# else asume its a tuple (bind_ip, bind_port)
elif ':' in config.SOCKET[0]: # assume ipv6 bind addresse
sock = socket.socket(socket.AF_INET6, socket.SOCK_STREAM)
elif '.' in config.SOCKET[0]: # assume ipv4 bind addresse
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
else:
raise ValueError("bad socket %s" % (config.SOCKET,))
sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
self.sock = sock
def close_socket(self):
"""close the socket depending of the config parameters"""
self.sock.close()
# if socket was an unix socket, delete it after closing.
if isinstance(config.SOCKET, str):
try:
os.remove(config.SOCKET)
except OSError as error: # pragma: no cover (should not happen)
sys.stderr.write("%s\n" % error)
sys.stderr.flush()
def close_connection(self, connection):
"""close a connection and clean read/write dict"""
# Clean up the connection
try:
del self.socket_data_read[connection]
except KeyError:
pass
try:
del self.socket_data_write[connection]
except KeyError:
pass
connection.close()
def run(self):
"""The main server loop"""
try:
sock = self.sock
sock.bind(config.SOCKET)
if isinstance(config.SOCKET, str):
os.chmod(config.SOCKET, config.socket_permission)
sock.listen(5)
self.socket_data_read[sock] = []
if config.debug:
sys.stderr.write('waiting for connections\n')
sys.stderr.flush()
while True:
# wait for a socket to read to or to write to
(rlist, wlist, _) = select.select(
self.socket_data_read.keys(), self.socket_data_write.keys(), []
)
for socket in rlist:
# if the socket is the main socket, there is a new connection to accept
if socket == sock:
connection, client_address = sock.accept()
if config.debug:
sys.stderr.write('connection from %s\n' % (client_address,))
sys.stderr.flush()
self.socket_data_read[connection] = []
# else there is data to read on a client socket
else:
self.read(socket)
for socket in wlist:
try:
data = self.socket_data_write[socket]
sent = socket.send(data)
data_not_sent = data[sent:]
if data_not_sent:
self.socket_data_write[socket] = data_not_sent
else:
self.close_connection(socket)
# the socket has been closed during read
except KeyError:
pass
except (KeyboardInterrupt, utils.Exit):
for socket in list(self.socket_data_read.keys()):
if socket != self.sock:
self.close_connection(sock)
raise
def read(self, connection):
"""Called then a connection is ready for reads"""
try:
# get the current buffer of the connection
buffer = self.socket_data_read[connection]
# read data
data = connection.recv(1024).decode('UTF-8')
if not data:
raise ValueError("connection closed")
if config.debug:
sys.stderr.write(data)
sys.stderr.flush()
# accumulate it in buffer
buffer.append(data)
# if data len too short to determine if we are on an empty line, we
# concatene datas in buffer
if len(data) < 2:
data = u"".join(buffer)
buffer = [data]
# We reach on empty line so the client has finish to send and wait for a response
if data[-2:] == "\n\n":
data = u"".join(buffer)
request = {}
# read data are like one key=value per line
for line in data.split("\n"):
line = line.strip()
try:
key, value = line.split(u"=", 1)
if value:
request[key] = value
# if value is empty, ignore it
except ValueError:
pass
# process the collected data in the action method
self.action(connection, request)
else:
self.socket_data_read[connection] = buffer
except (KeyboardInterrupt, utils.Exit):
self.close_connection(connection)
raise
except Exception as error:
sys.stderr.write("%s\n" % error)
sys.stderr.flush()
self.close_connection(connection)
def action(self, connection, request):
"""Called then the client has sent an empty line"""
id = None
# By default, we do not block emails
action = config.success_action
try:
if not config.database_is_initialized:
utils.database_init()
with utils.cursor() as cur:
try:
# only care if the protocol states is RCTP. If the policy delegation in postfix
# configuration is in smtpd_recipient_restrictions as said in the doc,
# possible states are RCPT and VRFY.
if 'protocol_state' in request and request['protocol_state'].upper() != "RCPT":
raise Pass()
# if user is authenticated, we filter by sasl username
if config.limit_by_sasl and u'sasl_username' in request:
id = request[u'sasl_username']
# else, if activated, we filter by ip source addresse
elif (
config.limit_by_ip and
u'client_address' in request and
utils.is_ip_limited(request[u'client_address'])
):
id = request[u'client_address']
# if the client neither send us client ip adresse nor sasl username, jump
# to the next section
else:
raise Pass()
# Here we are limiting agains sasl username or ip source addresses.
# for each limit periods, we count the number of mails already send.
# if the a limit is reach, we change action to fail (deny the mail).
for mail_nb, delta in config.limits_by_id.get(id, config.limits):
cur.execute(
(
"SELECT COUNT(*) FROM mail_count "
"WHERE id = %s AND date >= %s"
) % ((config.format_str,)*2),
(id, int(time.time() - delta))
)
nb = cur.fetchone()[0]
if config.debug:
sys.stderr.write("%03d/%03d hit since %ss\n" % (nb, mail_nb, delta))
sys.stderr.flush()
if nb >= mail_nb:
action = config.fail_action
if config.report and delta in config.report_limits:
utils.hit(cur, delta, id)
raise Pass()
except Pass:
pass
# If action is a success, record in the database that a new mail has just been sent
if action == config.success_action and id is not None:
if config.debug:
sys.stderr.write(u"insert id %s\n" % id)
sys.stderr.flush()
cur.execute(
"INSERT INTO mail_count VALUES (%s, %s)" % ((config.format_str,)*2),
(id, int(time.time()))
)
except utils.cursor.backend_module.Error as error:
utils.cursor.del_db()
action = config.db_error_action
sys.stderr.write("Database error: %r\n" % error)
data = u"action=%s\n\n" % action
if config.debug:
sys.stderr.write(data)
sys.stderr.flush()
# return the result to the client
self.socket_data_write[connection] = data.encode('UTF-8')
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