Source code for linkcheck.plugins.viruscheck

# Copyright (C) 2000-2014 Bastian Kleineidam
#
# 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 2 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, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
"""
Check page content for virus infection with clamav.
"""
import os
import socket
from . import _ContentPlugin
from .. import log, LOG_PLUGIN
from ..socketutil import create_socket


[docs]class VirusCheck(_ContentPlugin): """Checks the page content for virus infections with clamav. A local clamav daemon must be installed.""" def __init__(self, config): """Initialize clamav configuration.""" super().__init__(config) # XXX read config self.clamav_conf = get_clamav_conf(canonical_clamav_conf()) if not self.clamav_conf: log.warn(LOG_PLUGIN, "clamav daemon not found for VirusCheck plugin")
[docs] def applies_to(self, url_data): """Check for clamav and extern.""" return self.clamav_conf and not url_data.extern[0]
[docs] def check(self, url_data): """Try to ask GeoIP database for country info.""" data = url_data.get_raw_content() infected, errors = scan(data, self.clamav_conf) if infected or errors: for msg in infected: url_data.add_warning("Virus scan infection: %s" % msg) for msg in errors: url_data.add_warning("Virus scan error: %s" % msg) else: url_data.add_info("No viruses in data found.")
[docs] @classmethod def read_config(cls, configparser): """Read configuration file options.""" config = dict() section = cls.__name__ option = "clamavconf" if configparser.has_option(section, option): value = configparser.get(section, option) else: value = None config[option] = value return config
[docs]class ClamavError(Exception): """Raised on clamav errors.""" pass
[docs]class ClamdScanner: """Virus scanner using a clamd daemon process.""" def __init__(self, clamav_conf): """Initialize clamd daemon process sockets.""" self.infected = [] self.errors = [] self.sock, self.host = clamav_conf.new_connection() self.sock_rcvbuf = self.sock.getsockopt(socket.SOL_SOCKET, socket.SO_RCVBUF) self.wsock = self.new_scansock()
[docs] def new_scansock(self): """Return a connected socket for sending scan data to it.""" port = None try: self.sock.sendall(b"STREAM") port = None for dummy in range(60): data = self.sock.recv(self.sock_rcvbuf) i = data.find(b"PORT") if i != -1: port = int(data[i + 5:]) break except socket.error: self.sock.close() raise if port is None: raise ClamavError(_("clamd is not ready for stream scanning")) sockinfo = get_sockinfo(self.host, port=port) wsock = create_socket(socket.AF_INET, socket.SOCK_STREAM) try: wsock.connect(sockinfo[0][4]) except socket.error: wsock.close() raise return wsock
[docs] def scan(self, data): """Scan given data for viruses.""" self.wsock.sendall(data)
[docs] def close(self): """Get results and close clamd daemon sockets.""" self.wsock.close() data = self.sock.recv(self.sock_rcvbuf) while data: if b"FOUND\n" in data: self.infected.append(data.decode('UTF-8', 'replace')) if b"ERROR\n" in data: self.errors.append(data.decode('UTF-8', 'replace')) data = self.sock.recv(self.sock_rcvbuf) self.sock.close()
[docs]def canonical_clamav_conf(): """Default clamav configs for various platforms.""" if os.name == 'posix': clamavconf = "/etc/clamav/clamd.conf" elif os.name == 'nt': clamavconf = r"c:\clamav-devel\etc\clamd.conf" else: clamavconf = "clamd.conf" return clamavconf
[docs]def get_clamav_conf(filename): """Initialize clamav configuration.""" if os.path.isfile(filename): return ClamavConfig(filename) log.warn(LOG_PLUGIN, "No ClamAV config file found at %r.", filename)
[docs]def get_sockinfo(host, port=None): """Return socket.getaddrinfo for given host and port.""" family, socktype = socket.AF_INET, socket.SOCK_STREAM return socket.getaddrinfo(host, port, family, socktype)
[docs]class ClamavConfig(dict): """Clamav configuration wrapper, with clamd connection method.""" def __init__(self, filename): """Parse clamav configuration file.""" super().__init__() self.parseconf(filename) if self.get('ScannerDaemonOutputFormat'): raise ClamavError(_("ScannerDaemonOutputFormat must be disabled")) if self.get('TCPSocket') and self.get('LocalSocket'): raise ClamavError( _("only one of TCPSocket and LocalSocket must be enabled") )
[docs] def parseconf(self, filename): """Parse clamav configuration from given file.""" with open(filename) as fd: # yet another config format, sigh for line in fd: line = line.strip() if not line or line.startswith("#"): # ignore empty lines and comments continue split = line.split(None, 1) if len(split) == 1: self[split[0]] = True else: self[split[0]] = split[1]
[docs] def new_connection(self): """Connect to clamd for stream scanning. @return: tuple (connected socket, host) """ if self.get('LocalSocket'): host = 'localhost' sock = self.create_local_socket() elif self.get('TCPSocket'): host = self.get('TCPAddr', 'localhost') sock = self.create_tcp_socket(host) else: raise ClamavError(_("one of TCPSocket or LocalSocket must be enabled")) return sock, host
[docs] def create_local_socket(self): """Create local socket, connect to it and return socket object.""" sock = create_socket(socket.AF_UNIX, socket.SOCK_STREAM) addr = self['LocalSocket'] try: sock.connect(addr) except socket.error: sock.close() raise return sock
[docs] def create_tcp_socket(self, host): """Create tcp socket, connect to it and return socket object.""" port = int(self['TCPSocket']) sockinfo = get_sockinfo(host, port=port) sock = create_socket(socket.AF_INET, socket.SOCK_STREAM) try: sock.connect(sockinfo[0][4]) except socket.error: sock.close() raise return sock
[docs]def scan(data, clamconf): """Scan data for viruses. @return: (infection msgs, errors) @rtype: ([], []) """ try: scanner = ClamdScanner(clamconf) except socket.error: errmsg = _("Could not connect to ClamAV daemon.") return ([], [errmsg]) try: scanner.scan(data) finally: scanner.close() return scanner.infected, scanner.errors