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ftpserver.py
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ftpserver.py
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#!/usr/bin/env python
# $Id: ftpserver.py 988 2012-01-25 19:11:43Z g.rodola $
# pyftpdlib is released under the MIT license, reproduced below:
# ======================================================================
# Copyright (C) 2007-2012 Giampaolo Rodola' <g.rodola@gmail.com>
#
# All Rights Reserved
#
# Permission is hereby granted, free of charge, to any person
# obtaining a copy of this software and associated documentation
# files (the "Software"), to deal in the Software without
# restriction, including without limitation the rights to use,
# copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the
# Software is furnished to do so, subject to the following
# conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
# OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
# HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
# WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
# FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
# OTHER DEALINGS IN THE SOFTWARE.
#
# ======================================================================
"""pyftpdlib: RFC-959 asynchronous FTP server.
pyftpdlib implements a fully functioning asynchronous FTP server as
defined in RFC-959. A hierarchy of classes outlined below implement
the backend functionality for the FTPd:
[FTPServer] - the base class for the backend.
[FTPHandler] - a class representing the server-protocol-interpreter
(server-PI, see RFC-959). Each time a new connection occurs
FTPServer will create a new FTPHandler instance to handle the
current PI session.
[ActiveDTP], [PassiveDTP] - base classes for active/passive-DTP
backends.
[DTPHandler] - this class handles processing of data transfer
operations (server-DTP, see RFC-959).
[ThrottledDTPHandler] - a DTPHandler subclass implementing transfer
rates limits.
[DummyAuthorizer] - an "authorizer" is a class handling FTPd
authentications and permissions. It is used inside FTPHandler class
to verify user passwords, to get user's home directory and to get
permissions when a filesystem read/write occurs. "DummyAuthorizer"
is the base authorizer class providing a platform independent
interface for managing virtual users.
[AbstractedFS] - class used to interact with the file system,
providing a high level, cross-platform interface compatible
with both Windows and UNIX style filesystems.
[CallLater] - calls a function at a later time whithin the polling
loop asynchronously.
[AuthorizerError] - base class for authorizers exceptions.
pyftpdlib also provides 3 different logging streams through 3 functions
which can be overridden to allow for custom logging.
[log] - the main logger that logs the most important messages for
the end user regarding the FTPd.
[logline] - this function is used to log commands and responses
passing through the control FTP channel.
[logerror] - log traceback outputs occurring in case of errors.
Usage example:
>>> from pyftpdlib import ftpserver
>>> authorizer = ftpserver.DummyAuthorizer()
>>> authorizer.add_user('user', 'password', '/home/user', perm='elradfmw')
>>> authorizer.add_anonymous('/home/nobody')
>>> ftp_handler = ftpserver.FTPHandler
>>> ftp_handler.authorizer = authorizer
>>> address = ("127.0.0.1", 21)
>>> ftpd = ftpserver.FTPServer(address, ftp_handler)
>>> ftpd.serve_forever()
Serving FTP on 127.0.0.1:21
[]127.0.0.1:2503 connected.
127.0.0.1:2503 ==> 220 Ready.
127.0.0.1:2503 <== USER anonymous
127.0.0.1:2503 ==> 331 Username ok, send password.
127.0.0.1:2503 <== PASS ******
127.0.0.1:2503 ==> 230 Login successful.
[anonymous]@127.0.0.1:2503 User anonymous logged in.
127.0.0.1:2503 <== TYPE A
127.0.0.1:2503 ==> 200 Type set to: ASCII.
127.0.0.1:2503 <== PASV
127.0.0.1:2503 ==> 227 Entering passive mode (127,0,0,1,9,201).
127.0.0.1:2503 <== LIST
127.0.0.1:2503 ==> 150 File status okay. About to open data connection.
[anonymous]@127.0.0.1:2503 OK LIST "/". Transfer starting.
127.0.0.1:2503 ==> 226 Transfer complete.
[anonymous]@127.0.0.1:2503 Transfer complete. 706 bytes transmitted.
127.0.0.1:2503 <== QUIT
127.0.0.1:2503 ==> 221 Goodbye.
[anonymous]@127.0.0.1:2503 Disconnected.
"""
import asyncore
import asynchat
import socket
import os
import sys
import traceback
import errno
import time
import glob
import tempfile
import warnings
import random
import stat
import heapq
import optparse
from tarfile import filemode as _filemode
try:
import pwd
import grp
except ImportError:
pwd = grp = None
# http://code.google.com/p/pysendfile/
try:
from sendfile import sendfile
except ImportError:
sendfile = None
import dropbox
import config_flags
__all__ = ['proto_cmds', 'Error', 'log', 'logline', 'logerror', 'DummyAuthorizer',
'AuthorizerError', 'FTPHandler', 'FTPServer', 'PassiveDTP',
'ActiveDTP', 'DTPHandler', 'ThrottledDTPHandler', 'FileProducer',
'BufferedIteratorProducer', 'AbstractedFS', 'CallLater', 'CallEvery']
__pname__ = 'Python FTP server library (pyftpdlib)'
__ver__ = '0.7.0'
__date__ = '2012-01-25'
__author__ = "Giampaolo Rodola' <g.rodola@gmail.com>"
__web__ = 'http://code.google.com/p/pyftpdlib/'
_DISCONNECTED = frozenset((errno.ECONNRESET, errno.ENOTCONN, errno.ESHUTDOWN,
errno.ECONNABORTED, errno.EPIPE, errno.EBADF))
proto_cmds = {
'ABOR' : dict(perm=None, auth=True, arg=False,
help='Syntax: ABOR (abort transfer).'),
'ALLO' : dict(perm=None, auth=True, arg=True,
help='Syntax: ALLO <SP> bytes (noop; allocate storage).'),
'APPE' : dict(perm='a', auth=True, arg=True,
help='Syntax: APPE <SP> file-name (append data to file).'),
'CDUP' : dict(perm='e', auth=True, arg=False,
help='Syntax: CDUP (go to parent directory).'),
'CWD' : dict(perm='e', auth=True, arg=None,
help='Syntax: CWD [<SP> dir-name] (change working directory).'),
'DELE' : dict(perm='d', auth=True, arg=True,
help='Syntax: DELE <SP> file-name (delete file).'),
'EPRT' : dict(perm=None, auth=True, arg=True,
help='Syntax: EPRT <SP> |proto|ip|port| (extended active mode).'),
'EPSV' : dict(perm=None, auth=True, arg=None,
help='Syntax: EPSV [<SP> proto/"ALL"] (extended passive mode).'),
'FEAT' : dict(perm=None, auth=False, arg=False,
help='Syntax: FEAT (list all new features supported).'),
'HELP' : dict(perm=None, auth=False, arg=None,
help='Syntax: HELP [<SP> cmd] (show help).'),
'LIST' : dict(perm='l', auth=True, arg=None,
help='Syntax: LIST [<SP> path] (list files).'),
'MDTM' : dict(perm='l', auth=True, arg=True,
help='Syntax: MDTM [<SP> path] (file last modification time).'),
'MLSD' : dict(perm='l', auth=True, arg=None,
help='Syntax: MLSD [<SP> path] (list directory).'),
'MLST' : dict(perm='l', auth=True, arg=None,
help='Syntax: MLST [<SP> path] (show information about path).'),
'MODE' : dict(perm=None, auth=True, arg=True,
help='Syntax: MODE <SP> mode (noop; set data transfer mode).'),
'MKD' : dict(perm='m', auth=True, arg=True,
help='Syntax: MKD <SP> path (create directory).'),
'NLST' : dict(perm='l', auth=True, arg=None,
help='Syntax: NLST [<SP> path] (list path in a compact form).'),
'NOOP' : dict(perm=None, auth=False, arg=False,
help='Syntax: NOOP (just do nothing).'),
'OPTS' : dict(perm=None, auth=True, arg=True,
help='Syntax: OPTS <SP> cmd [<SP> option] (set option for command).'),
'PASS' : dict(perm=None, auth=False, arg=True,
help='Syntax: PASS <SP> password (set user password).'),
'PASV' : dict(perm=None, auth=True, arg=False,
help='Syntax: PASV (open passive data connection).'),
'PORT' : dict(perm=None, auth=True, arg=True,
help='Syntax: PORT <sp> h1,h2,h3,h4,p1,p2 (open active data connection).'),
'PWD' : dict(perm=None, auth=True, arg=False,
help='Syntax: PWD (get current working directory).'),
'QUIT' : dict(perm=None, auth=False, arg=False,
help='Syntax: QUIT (quit current session).'),
'REIN' : dict(perm=None, auth=True, arg=False,
help='Syntax: REIN (flush account).'),
'REST' : dict(perm=None, auth=True, arg=True,
help='Syntax: REST <SP> offset (set file offset).'),
'RETR' : dict(perm='r', auth=True, arg=True,
help='Syntax: RETR <SP> file-name (retrieve a file).'),
'RMD' : dict(perm='d', auth=True, arg=True,
help='Syntax: RMD <SP> dir-name (remove directory).'),
'RNFR' : dict(perm='f', auth=True, arg=True,
help='Syntax: RNFR <SP> file-name (rename (source name)).'),
'RNTO' : dict(perm='f', auth=True, arg=True,
help='Syntax: RNTO <SP> file-name (rename (destination name)).'),
'SITE' : dict(perm=None, auth=False, arg=True,
help='Syntax: SITE <SP> site-command (execute SITE command).'),
'SITE HELP' : dict(perm=None, auth=False, arg=None,
help='Syntax: SITE HELP [<SP> site-command] (show SITE command help).'),
'SITE CHMOD': dict(perm='M', auth=True, arg=True,
help='Syntax: SITE CHMOD <SP> mode path (change file mode).'),
'SIZE' : dict(perm='l', auth=True, arg=True,
help='Syntax: SIZE <SP> file-name (get file size).'),
'STAT' : dict(perm='l', auth=False, arg=None,
help='Syntax: STAT [<SP> path name] (server stats [list files]).'),
'STOR' : dict(perm='w', auth=True, arg=True,
help='Syntax: STOR <SP> file-name (store a file).'),
'STOU' : dict(perm='w', auth=True, arg=None,
help='Syntax: STOU [<SP> file-name] (store a file with a unique name).'),
'STRU' : dict(perm=None, auth=True, arg=True,
help='Syntax: STRU <SP> type (noop; set file structure).'),
'SYST' : dict(perm=None, auth=False, arg=False,
help='Syntax: SYST (get operating system type).'),
'TYPE' : dict(perm=None, auth=True, arg=True,
help='Syntax: TYPE <SP> [A | I] (set transfer type).'),
'USER' : dict(perm=None, auth=False, arg=True,
help='Syntax: USER <SP> user-name (set username).'),
'XCUP' : dict(perm='e', auth=True, arg=False,
help='Syntax: XCUP (obsolete; go to parent directory).'),
'XCWD' : dict(perm='e', auth=True, arg=None,
help='Syntax: XCWD [<SP> dir-name] (obsolete; change directory).'),
'XMKD' : dict(perm='m', auth=True, arg=True,
help='Syntax: XMKD <SP> dir-name (obsolete; create directory).'),
'XPWD' : dict(perm=None, auth=True, arg=False,
help='Syntax: XPWD (obsolete; get current dir).'),
'XRMD' : dict(perm='d', auth=True, arg=True,
help='Syntax: XRMD <SP> dir-name (obsolete; remove directory).'),
}
if not hasattr(os, 'chmod'):
del proto_cmds['SITE CHMOD']
# A wrapper around os.strerror() which may be not available
# on all platforms (e.g. pythonCE). Expected arg is a
# EnvironmentError or derived class instance.
#if hasattr(os, 'strerror'):
# _strerror = lambda err: os.strerror(err.errno)
#else:
# _strerror = lambda err: err.strerror
_strerror = lambda err: str(err)
class _Scheduler(object):
"""Run the scheduled functions due to expire soonest (if any)."""
def __init__(self):
# the heap used for the scheduled tasks
self._tasks = []
self._cancellations = 0
def __call__(self):
now = time.time()
calls = []
while self._tasks:
if now < self._tasks[0].timeout:
break
call = heapq.heappop(self._tasks)
if not call.cancelled:
calls.append(call)
else:
self._cancellations -= 1
for call in calls:
if call._repush:
heapq.heappush(self._tasks, call)
call._repush = False
continue
try:
call.call()
except (KeyboardInterrupt, SystemExit, asyncore.ExitNow):
raise
except:
logerror(traceback.format_exc())
# remove cancelled tasks and re-heapify the queue if the
# number of cancelled tasks is more than the half of the
# entire queue
if self._cancellations > 512 \
and self._cancellations > (len(self._tasks) >> 1):
self._cancellations = 0
self._tasks = [x for x in self._tasks if not x.cancelled]
self.reheapify()
def register(self, what):
heapq.heappush(self._tasks, what)
def unregister(self, what):
self._cancellations += 1
def reheapify(self):
heapq.heapify(self._tasks)
_scheduler = _Scheduler()
# dirty hack to support property.setter on python < 2.6
if not hasattr(property, "setter"):
class property(property):
def setter(self, value):
cls_ns = sys._getframe(1).f_locals
for k, v in cls_ns.iteritems():
if v == self:
name = k
break
cls_ns[name] = property(self.fget, value, self.fdel, self.__doc__)
return cls_ns[name]
_months_map = {1:'Jan', 2:'Feb', 3:'Mar', 4:'Apr', 5:'May', 6:'Jun', 7:'Jul',
8:'Aug', 9:'Sep', 10:'Oct', 11:'Nov', 12:'Dec'}
class CallLater(object):
"""Calls a function at a later time.
It can be used to asynchronously schedule a call within the polling
loop without blocking it. The instance returned is an object that
can be used to cancel or reschedule the call.
"""
__slots__ = ('_delay', '_target', '_args', '_kwargs', '_errback',
'_repush', 'timeout', 'cancelled')
def __init__(self, seconds, target, *args, **kwargs):
"""
- (int) seconds: the number of seconds to wait
- (obj) target: the callable object to call later
- args: the arguments to call it with
- kwargs: the keyword arguments to call it with; a special
'_errback' parameter can be passed: it is a callable
called in case target function raises an exception.
"""
assert callable(target), "%s is not callable" % target
assert sys.maxint >= seconds >= 0, "%s is not greater than or equal " \
"to 0 seconds" % seconds
self._delay = seconds
self._target = target
self._args = args
self._kwargs = kwargs
self._errback = kwargs.pop('_errback', None)
self._repush = False
# seconds from the epoch at which to call the function
self.timeout = time.time() + self._delay
self.cancelled = False
_scheduler.register(self)
def __lt__(self, other):
return self.timeout < other.timeout
def __le__(self, other):
return self.timeout <= other.timeout
def _post_call(self, exc):
if not self.cancelled:
self.cancel()
def call(self):
"""Call this scheduled function."""
assert not self.cancelled, "Already cancelled"
exc = None
try:
try:
self._target(*self._args, **self._kwargs)
except (KeyboardInterrupt, SystemExit, asyncore.ExitNow):
raise
except Exception, exc:
if self._errback is not None:
self._errback()
else:
raise
finally:
self._post_call(exc)
def reset(self):
"""Reschedule this call resetting the current countdown."""
assert not self.cancelled, "Already cancelled"
self.timeout = time.time() + self._delay
self._repush = True
def delay(self, seconds):
"""Reschedule this call for a later time."""
assert not self.cancelled, "Already cancelled."
assert sys.maxint >= seconds >= 0, "%s is not greater than or equal " \
"to 0 seconds" % seconds
self._delay = seconds
newtime = time.time() + self._delay
if newtime > self.timeout:
self.timeout = newtime
self._repush = True
else:
# XXX - slow, can be improved
self.timeout = newtime
_scheduler.reheapify()
def cancel(self):
"""Unschedule this call."""
assert not self.cancelled, "Already cancelled"
self.cancelled = True
del self._target, self._args, self._kwargs, self._errback
_scheduler.unregister(self)
class CallEvery(CallLater):
"""Calls a function every x seconds.
It accepts the same arguments as CallLater and shares the same API.
"""
def _post_call(self, exc):
if not self.cancelled:
if exc:
self.cancel()
else:
self.timeout = time.time() + self._delay
_scheduler.register(self)
# --- library defined exceptions
class Error(Exception):
"""Base class for module exceptions."""
class AuthorizerError(Error):
"""Base class for authorizer exceptions."""
class _FileReadWriteError(OSError):
"""Exception raised when reading or writing a file during a transfer."""
# --- loggers
def log(msg):
"""Log messages intended for the end user."""
print msg
def logline(msg):
"""Log commands and responses passing through the command channel."""
print msg
def logerror(msg):
"""Log traceback outputs occurring in case of errors."""
sys.stderr.write(str(msg) + '\n')
sys.stderr.flush()
# --- authorizers
class DummyAuthorizer(object):
"""Basic "dummy" authorizer class, suitable for subclassing to
create your own custom authorizers.
An "authorizer" is a class handling authentications and permissions
of the FTP server. It is used inside FTPHandler class for verifying
user's password, getting users home directory, checking user
permissions when a file read/write event occurs and changing user
before accessing the filesystem.
DummyAuthorizer is the base authorizer, providing a platform
independent interface for managing "virtual" FTP users. System
dependent authorizers can by written by subclassing this base
class and overriding appropriate methods as necessary.
"""
read_perms = "elr"
write_perms = "adfmwM"
def __init__(self):
self.user_table = {}
def add_user(self, username, password, homedir, perm='elr',
msg_login="Login successful.", msg_quit="Goodbye."):
"""Add a user to the virtual users table.
AuthorizerError exceptions raised on error conditions such as
invalid permissions, missing home directory or duplicate usernames.
Optional perm argument is a string referencing the user's
permissions explained below:
Read permissions:
- "e" = change directory (CWD command)
- "l" = list files (LIST, NLST, STAT, MLSD, MLST, SIZE, MDTM commands)
- "r" = retrieve file from the server (RETR command)
Write permissions:
- "a" = append data to an existing file (APPE command)
- "d" = delete file or directory (DELE, RMD commands)
- "f" = rename file or directory (RNFR, RNTO commands)
- "m" = create directory (MKD command)
- "w" = store a file to the server (STOR, STOU commands)
- "M" = change file mode (SITE CHMOD command)
Optional msg_login and msg_quit arguments can be specified to
provide customized response strings when user log-in and quit.
"""
if self.has_user(username):
raise ValueError('user "%s" already exists' % username)
if not os.path.isdir(homedir):
raise ValueError('no such directory: "%s"' % homedir)
homedir = os.path.realpath(homedir)
self._check_permissions(username, perm)
dic = {'pwd': str(password),
'home': homedir,
'perm': perm,
'operms': {},
'msg_login': str(msg_login),
'msg_quit': str(msg_quit)
}
self.user_table[username] = dic
def add_anonymous(self, homedir, **kwargs):
"""Add an anonymous user to the virtual users table.
AuthorizerError exception raised on error conditions such as
invalid permissions, missing home directory, or duplicate
anonymous users.
The keyword arguments in kwargs are the same expected by
add_user method: "perm", "msg_login" and "msg_quit".
The optional "perm" keyword argument is a string defaulting to
"elr" referencing "read-only" anonymous user's permissions.
Using write permission values ("adfmwM") results in a
RuntimeWarning.
"""
DummyAuthorizer.add_user(self, 'anonymous', '', homedir, **kwargs)
def remove_user(self, username):
"""Remove a user from the virtual users table."""
del self.user_table[username]
def override_perm(self, username, directory, perm, recursive=False):
"""Override permissions for a given directory."""
self._check_permissions(username, perm)
if not os.path.isdir(directory):
raise ValueError('no such directory: "%s"' % directory)
directory = os.path.normcase(os.path.realpath(directory))
home = os.path.normcase(self.get_home_dir(username))
if directory == home:
raise ValueError("can't override home directory permissions")
if not self._issubpath(directory, home):
raise ValueError("path escapes user home directory")
self.user_table[username]['operms'][directory] = perm, recursive
def validate_authentication(self, username, password):
"""Return True if the supplied username and password match the
stored credentials."""
if not self.has_user(username):
return False
if username == 'anonymous':
return True
return self.user_table[username]['pwd'] == password
def impersonate_user(self, username, password):
"""Impersonate another user (noop).
It is always called before accessing the filesystem.
By default it does nothing. The subclass overriding this
method is expected to provide a mechanism to change the
current user.
"""
def terminate_impersonation(self, username):
"""Terminate impersonation (noop).
It is always called after having accessed the filesystem.
By default it does nothing. The subclass overriding this
method is expected to provide a mechanism to switch back
to the original user.
"""
def has_user(self, username):
"""Whether the username exists in the virtual users table."""
return username in self.user_table
def has_perm(self, username, perm, path=None):
"""Whether the user has permission over path (an absolute
pathname of a file or a directory).
Expected perm argument is one of the following letters:
"elradfmwM".
"""
if path is None:
return perm in self.user_table[username]['perm']
path = os.path.normcase(path)
for dir in self.user_table[username]['operms'].keys():
operm, recursive = self.user_table[username]['operms'][dir]
if self._issubpath(path, dir):
if recursive:
return perm in operm
if (path == dir) or (os.path.dirname(path) == dir \
and not os.path.isdir(path)):
return perm in operm
return perm in self.user_table[username]['perm']
def get_perms(self, username):
"""Return current user permissions."""
return self.user_table[username]['perm']
def get_home_dir(self, username):
"""Return the user's home directory."""
return self.user_table[username]['home']
def get_msg_login(self, username):
"""Return the user's login message."""
return self.user_table[username]['msg_login']
def get_msg_quit(self, username):
"""Return the user's quitting message."""
return self.user_table[username]['msg_quit']
def _check_permissions(self, username, perm):
warned = 0
for p in perm:
if p not in self.read_perms + self.write_perms:
raise ValueError('no such permission "%s"' % p)
if (username == 'anonymous') and (p in self.write_perms) and not warned:
warnings.warn("write permissions assigned to anonymous user.",
RuntimeWarning)
warned = 1
def _issubpath(self, a, b):
"""Return True if a is a sub-path of b or if the paths are equal."""
p1 = a.rstrip(os.sep).split(os.sep)
p2 = b.rstrip(os.sep).split(os.sep)
return p1[:len(p2)] == p2
# Dropbox authorizer also keeps track of tokens
class DropboxAuthorizer(DummyAuthorizer):
def __init__(self):
DummyAuthorizer.__init__(self)
DummyAuthorizer.__init__(self)
self.tokens = {}
def add_user_w_token(self, username, password, token, perm='lrw'):
self.tokens[username] = token
DummyAuthorizer.add_user(self, username, password, '.', perm)
def get_token(self, username):
return self.tokens.get(username, None)
# --- DTP classes
class PassiveDTP(object, asyncore.dispatcher):
"""This class is an asyncore.dispatcher subclass. It creates a
socket listening on a local port, dispatching the resultant
connection to DTPHandler.
- (int) timeout: the timeout for a remote client to establish
connection with the listening socket. Defaults to 30 seconds.
"""
timeout = 30
def __init__(self, cmd_channel, extmode=False):
"""Initialize the passive data server.
- (instance) cmd_channel: the command channel class instance.
- (bool) extmode: wheter use extended passive mode response type.
"""
self.cmd_channel = cmd_channel
self.log = cmd_channel.log
self.log_exception = cmd_channel.log_exception
self._closed = False
asyncore.dispatcher.__init__(self)
if self.timeout:
self._idler = CallLater(self.timeout, self.handle_timeout,
_errback=self.handle_error)
else:
self._idler = None
local_ip = self.cmd_channel.socket.getsockname()[0]
if local_ip in self.cmd_channel.masquerade_address_map:
masqueraded_ip = self.cmd_channel.masquerade_address_map[local_ip]
elif self.cmd_channel.masquerade_address:
masqueraded_ip = self.cmd_channel.masquerade_address
else:
masqueraded_ip = None
self.create_socket(self.cmd_channel._af, socket.SOCK_STREAM)
if self.cmd_channel.passive_ports is None:
# By using 0 as port number value we let kernel choose a
# free unprivileged random port.
self.bind((local_ip, 0))
else:
ports = list(self.cmd_channel.passive_ports)
while ports:
port = ports.pop(random.randint(0, len(ports) -1))
self.set_reuse_addr()
try:
self.bind((local_ip, port))
except socket.error, err:
if err.args[0] == errno.EADDRINUSE: # port already in use
if ports:
continue
# If cannot use one of the ports in the configured
# range we'll use a kernel-assigned port, and log
# a message reporting the issue.
# By using 0 as port number value we let kernel
# choose a free unprivileged random port.
else:
self.bind((local_ip, 0))
self.log(
"Can't find a valid passive port in the "
"configured range. A random kernel-assigned "
"port will be used."
)
else:
raise
else:
break
self.listen(5)
port = self.socket.getsockname()[1]
if not extmode:
ip = masqueraded_ip or local_ip
if ip.startswith('::ffff:'):
# In this scenario, the server has an IPv6 socket, but
# the remote client is using IPv4 and its address is
# represented as an IPv4-mapped IPv6 address which
# looks like this ::ffff:151.12.5.65, see:
# http://en.wikipedia.org/wiki/IPv6#IPv4-mapped_addresses
# http://tools.ietf.org/html/rfc3493.html#section-3.7
# We truncate the first bytes to make it look like a
# common IPv4 address.
ip = ip[7:]
# The format of 227 response in not standardized.
# This is the most expected:
self.cmd_channel.respond('227 Entering passive mode (%s,%d,%d).' % (
ip.replace('.', ','), port // 256, port % 256))
else:
self.cmd_channel.respond('229 Entering extended passive mode '
'(|||%d|).' % port)
def set_reuse_addr(self):
# overridden for convenience; avoid to reuse address on Windows
if (os.name in ('nt', 'ce')) or (sys.platform == 'cygwin'):
return
asyncore.dispatcher.set_reuse_addr(self)
# --- connection / overridden
def handle_accept(self):
"""Called when remote client initiates a connection."""
if not self.cmd_channel.connected:
return self.close()
try:
sock, addr = self.accept()
except TypeError:
# sometimes accept() might return None (see issue 91)
return
except socket.error, err:
# ECONNABORTED might be thrown on *BSD (see issue 105)
if err.args[0] != errno.ECONNABORTED:
self.log_exception(self)
return
else:
# sometimes addr == None instead of (ip, port) (see issue 104)
if addr == None:
return
# Check the origin of data connection. If not expressively
# configured we drop the incoming data connection if remote
# IP address does not match the client's IP address.
if self.cmd_channel.remote_ip != addr[0]:
if not self.cmd_channel.permit_foreign_addresses:
try:
sock.close()
except socket.error:
pass
msg = 'Rejected data connection from foreign address %s:%s.' \
%(addr[0], addr[1])
self.cmd_channel.respond("425 %s" % msg)
self.log(msg)
# do not close listening socket: it couldn't be client's blame
return
else:
# site-to-site FTP allowed
msg = 'Established data connection with foreign address %s:%s.'\
% (addr[0], addr[1])
self.log(msg)
# Immediately close the current channel (we accept only one
# connection at time) and avoid running out of max connections
# limit.
self.close()
# delegate such connection to DTP handler
if self.cmd_channel.connected:
handler = self.cmd_channel.dtp_handler(sock, self.cmd_channel)
if handler.connected:
self.cmd_channel.data_channel = handler
self.cmd_channel._on_dtp_connection()
def handle_timeout(self):
if self.cmd_channel.connected:
self.cmd_channel.respond("421 Passive data channel timed out.")
self.close()
def writable(self):
return 0
def handle_error(self):
"""Called to handle any uncaught exceptions."""
try:
raise
except (KeyboardInterrupt, SystemExit, asyncore.ExitNow):
raise
except:
logerror(traceback.format_exc())
self.close()
def close(self):
if not self._closed:
self._closed = True
asyncore.dispatcher.close(self)
if self._idler is not None and not self._idler.cancelled:
self._idler.cancel()
class ActiveDTP(object, asyncore.dispatcher):
"""This class is an asyncore.disptacher subclass. It creates a
socket resulting from the connection to a remote user-port,
dispatching it to DTPHandler.
- (int) timeout: the timeout for us to establish connection with
the client's listening data socket.
"""
timeout = 30
def __init__(self, ip, port, cmd_channel):
"""Initialize the active data channel attemping to connect
to remote data socket.
- (str) ip: the remote IP address.
- (int) port: the remote port.
- (instance) cmd_channel: the command channel class instance.
"""
self.cmd_channel = cmd_channel
self.log = cmd_channel.log
self.log_exception = cmd_channel.log_exception
self._closed = True
asyncore.dispatcher.__init__(self)
if self.timeout:
self._idler = CallLater(self.timeout, self.handle_timeout,
_errback=self.handle_error)
else:
self._idler = None
if ip.count('.') == 4:
self._cmd = "PORT"
self._normalized_addr = "%s:%s" % (ip, port)
else:
self._cmd = "EPRT"
self._normalized_addr = "[%s]:%s" % (ip, port)
self.create_socket(self.cmd_channel._af, socket.SOCK_STREAM)
# Have the active connection come from the same IP address
# as the command channel, see:
# http://code.google.com/p/pyftpdlib/issues/detail?id=123
source_ip = self.cmd_channel.socket.getsockname()[0]
self.bind((source_ip, 0))
try:
self.connect((ip, port))
except (socket.gaierror, socket.error):
self.handle_expt()
# overridden to prevent unhandled read/write event messages to
# be printed by asyncore on Python < 2.6
def handle_write(self):
pass
def handle_read(self):
pass
def handle_connect(self):
"""Called when connection is established."""
if self._idler is not None and not self._idler.cancelled:
self._idler.cancel()
if not self.cmd_channel.connected:
return self.close()
# fix for asyncore on python < 2.6, meaning we aren't
# actually connected.
# test_active_conn_error tests this condition
err = self.socket.getsockopt(socket.SOL_SOCKET, socket.SO_ERROR)
if err != 0:
raise socket.error(err)
#
msg = 'Active data connection established.'
self.cmd_channel.respond('200 ' + msg)
self.cmd_channel.log_cmd(self._cmd, self._normalized_addr, 200, msg)
#
if not self.cmd_channel.connected:
return self.close()
# delegate such connection to DTP handler
handler = self.cmd_channel.dtp_handler(self.socket, self.cmd_channel)
self.cmd_channel.data_channel = handler
self.cmd_channel._on_dtp_connection()
# Can't close right now as the handler would have the socket
# object disconnected. This class will be "closed" once the
# data transfer is completed or the client disconnects.
#self.close()
def handle_timeout(self):
if self.cmd_channel.connected:
msg = "Active data channel timed out."
self.cmd_channel.respond("421 " + msg)
self.cmd_channel.log_cmd(self._cmd, self._normalized_addr, 421, msg)
self.close()
def handle_expt(self):
if self.cmd_channel.connected:
msg = "Can't connect to specified address."
self.cmd_channel.respond("425 " + msg)
self.cmd_channel.log_cmd(self._cmd, self._normalized_addr, 425, msg)
self.close()
def handle_error(self):
"""Called to handle any uncaught exceptions."""
try:
raise
except (KeyboardInterrupt, SystemExit, asyncore.ExitNow):
raise
except (socket.gaierror, socket.error):
pass
except:
self.log_exception(self)
self.handle_expt()
def close(self):
if not self._closed:
self._closed = True
asyncore.dispatcher.close(self)
if self._idler is not None and not self._idler.cancelled:
self._idler.cancel()
class DTPHandler(object, asynchat.async_chat):
"""Class handling server-data-transfer-process (server-DTP, see
RFC-959) managing data-transfer operations involving sending
and receiving data.
Class attributes:
- (int) timeout: the timeout which roughly is the maximum time we
permit data transfers to stall for with no progress. If the
timeout triggers, the remote client will be kicked off
(defaults 300).
- (int) ac_in_buffer_size: incoming data buffer size (defaults 65536)
- (int) ac_out_buffer_size: outgoing data buffer size (defaults 65536)
"""
timeout = 300
ac_in_buffer_size = 65536
ac_out_buffer_size = 65536
def __init__(self, sock_obj, cmd_channel):
"""Initialize the command channel.
- (instance) sock_obj: the socket object instance of the newly
established connection.
- (instance) cmd_channel: the command channel class instance.
"""
self.cmd_channel = cmd_channel
self.file_obj = None
self.receive = False