/usr/lib/python3/dist-packages/pyftpdlib/filesystems.py is in python3-pyftpdlib 1.4.0-1.
This file is owned by root:root, with mode 0o644.
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# ======================================================================
# Copyright (C) 2007-2014 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.
#
# ======================================================================
import os
import time
import tempfile
import stat
try:
from stat import filemode as _filemode # PY 3.3
except ImportError:
from tarfile import filemode as _filemode
try:
import pwd
import grp
except ImportError:
pwd = grp = None
from pyftpdlib._compat import PY3, u, unicode, property
__all__ = ['FilesystemError', 'AbstractedFS']
_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'}
# ===================================================================
# --- custom exceptions
# ===================================================================
class FilesystemError(Exception):
"""Custom class for filesystem-related exceptions.
You can raise this from an AbstractedFS subclass in order to
send a customized error string to the client.
"""
# ===================================================================
# --- base class
# ===================================================================
class AbstractedFS(object):
"""A class used to interact with the file system, providing a
cross-platform interface compatible with both Windows and
UNIX style filesystems where all paths use "/" separator.
AbstractedFS distinguishes between "real" filesystem paths and
"virtual" ftp paths emulating a UNIX chroot jail where the user
can not escape its home directory (example: real "/home/user"
path will be seen as "/" by the client)
It also provides some utility methods and wraps around all os.*
calls involving operations against the filesystem like creating
files or removing directories.
FilesystemError exception can be raised from within any of
the methods below in order to send a customized error string
to the client.
"""
def __init__(self, root, cmd_channel):
"""
- (str) root: the user "real" home directory (e.g. '/home/user')
- (instance) cmd_channel: the FTPHandler class instance
"""
assert isinstance(root, unicode)
# Set initial current working directory.
# By default initial cwd is set to "/" to emulate a chroot jail.
# If a different behavior is desired (e.g. initial cwd = root,
# to reflect the real filesystem) users overriding this class
# are responsible to set _cwd attribute as necessary.
self._cwd = u('/')
self._root = root
self.cmd_channel = cmd_channel
@property
def root(self):
"""The user home directory."""
return self._root
@property
def cwd(self):
"""The user current working directory."""
return self._cwd
@root.setter
def root(self, path):
assert isinstance(path, unicode), path
self._root = path
@cwd.setter
def cwd(self, path):
assert isinstance(path, unicode), path
self._cwd = path
# --- Pathname / conversion utilities
def ftpnorm(self, ftppath):
"""Normalize a "virtual" ftp pathname (typically the raw string
coming from client) depending on the current working directory.
Example (having "/foo" as current working directory):
>>> ftpnorm('bar')
'/foo/bar'
Note: directory separators are system independent ("/").
Pathname returned is always absolutized.
"""
assert isinstance(ftppath, unicode), ftppath
if os.path.isabs(ftppath):
p = os.path.normpath(ftppath)
else:
p = os.path.normpath(os.path.join(self.cwd, ftppath))
# normalize string in a standard web-path notation having '/'
# as separator.
if os.sep == "\\":
p = p.replace("\\", "/")
# os.path.normpath supports UNC paths (e.g. "//a/b/c") but we
# don't need them. In case we get an UNC path we collapse
# redundant separators appearing at the beginning of the string
while p[:2] == '//':
p = p[1:]
# Anti path traversal: don't trust user input, in the event
# that self.cwd is not absolute, return "/" as a safety measure.
# This is for extra protection, maybe not really necessary.
if not os.path.isabs(p):
p = u("/")
return p
def ftp2fs(self, ftppath):
"""Translate a "virtual" ftp pathname (typically the raw string
coming from client) into equivalent absolute "real" filesystem
pathname.
Example (having "/home/user" as root directory):
>>> ftp2fs("foo")
'/home/user/foo'
Note: directory separators are system dependent.
"""
assert isinstance(ftppath, unicode), ftppath
# as far as I know, it should always be path traversal safe...
if os.path.normpath(self.root) == os.sep:
return os.path.normpath(self.ftpnorm(ftppath))
else:
p = self.ftpnorm(ftppath)[1:]
return os.path.normpath(os.path.join(self.root, p))
def fs2ftp(self, fspath):
"""Translate a "real" filesystem pathname into equivalent
absolute "virtual" ftp pathname depending on the user's
root directory.
Example (having "/home/user" as root directory):
>>> fs2ftp("/home/user/foo")
'/foo'
As for ftpnorm, directory separators are system independent
("/") and pathname returned is always absolutized.
On invalid pathnames escaping from user's root directory
(e.g. "/home" when root is "/home/user") always return "/".
"""
assert isinstance(fspath, unicode), fspath
if os.path.isabs(fspath):
p = os.path.normpath(fspath)
else:
p = os.path.normpath(os.path.join(self.root, fspath))
if not self.validpath(p):
return u('/')
p = p.replace(os.sep, "/")
p = p[len(self.root):]
if not p.startswith('/'):
p = '/' + p
return p
def validpath(self, path):
"""Check whether the path belongs to user's home directory.
Expected argument is a "real" filesystem pathname.
If path is a symbolic link it is resolved to check its real
destination.
Pathnames escaping from user's root directory are considered
not valid.
"""
assert isinstance(path, unicode), path
root = self.realpath(self.root)
path = self.realpath(path)
if not root.endswith(os.sep):
root = root + os.sep
if not path.endswith(os.sep):
path = path + os.sep
if path[0:len(root)] == root:
return True
return False
# --- Wrapper methods around open() and tempfile.mkstemp
def open(self, filename, mode):
"""Open a file returning its handler."""
assert isinstance(filename, unicode), filename
return open(filename, mode)
def mkstemp(self, suffix='', prefix='', dir=None, mode='wb'):
"""A wrap around tempfile.mkstemp creating a file with a unique
name. Unlike mkstemp it returns an object with a file-like
interface.
"""
class FileWrapper:
def __init__(self, fd, name):
self.file = fd
self.name = name
def __getattr__(self, attr):
return getattr(self.file, attr)
text = 'b' not in mode
# max number of tries to find out a unique file name
tempfile.TMP_MAX = 50
fd, name = tempfile.mkstemp(suffix, prefix, dir, text=text)
file = os.fdopen(fd, mode)
return FileWrapper(file, name)
# --- Wrapper methods around os.* calls
def chdir(self, path):
"""Change the current directory."""
# note: process cwd will be reset by the caller
assert isinstance(path, unicode), path
os.chdir(path)
self._cwd = self.fs2ftp(path)
def mkdir(self, path):
"""Create the specified directory."""
assert isinstance(path, unicode), path
os.mkdir(path)
def listdir(self, path):
"""List the content of a directory."""
assert isinstance(path, unicode), path
return os.listdir(path)
def rmdir(self, path):
"""Remove the specified directory."""
assert isinstance(path, unicode), path
os.rmdir(path)
def remove(self, path):
"""Remove the specified file."""
assert isinstance(path, unicode), path
os.remove(path)
def rename(self, src, dst):
"""Rename the specified src file to the dst filename."""
assert isinstance(src, unicode), src
assert isinstance(dst, unicode), dst
os.rename(src, dst)
def chmod(self, path, mode):
"""Change file/directory mode."""
assert isinstance(path, unicode), path
if not hasattr(os, 'chmod'):
raise NotImplementedError
os.chmod(path, mode)
def stat(self, path):
"""Perform a stat() system call on the given path."""
# on python 2 we might also get bytes from os.lisdir()
# assert isinstance(path, unicode), path
return os.stat(path)
if hasattr(os, 'lstat'):
def lstat(self, path):
"""Like stat but does not follow symbolic links."""
# on python 2 we might also get bytes from os.lisdir()
# assert isinstance(path, unicode), path
return os.lstat(path)
else:
lstat = stat
if hasattr(os, 'readlink'):
def readlink(self, path):
"""Return a string representing the path to which a
symbolic link points.
"""
assert isinstance(path, unicode), path
return os.readlink(path)
# --- Wrapper methods around os.path.* calls
def isfile(self, path):
"""Return True if path is a file."""
assert isinstance(path, unicode), path
return os.path.isfile(path)
def islink(self, path):
"""Return True if path is a symbolic link."""
assert isinstance(path, unicode), path
return os.path.islink(path)
def isdir(self, path):
"""Return True if path is a directory."""
assert isinstance(path, unicode), path
return os.path.isdir(path)
def getsize(self, path):
"""Return the size of the specified file in bytes."""
assert isinstance(path, unicode), path
return os.path.getsize(path)
def getmtime(self, path):
"""Return the last modified time as a number of seconds since
the epoch."""
assert isinstance(path, unicode), path
return os.path.getmtime(path)
def realpath(self, path):
"""Return the canonical version of path eliminating any
symbolic links encountered in the path (if they are
supported by the operating system).
"""
assert isinstance(path, unicode), path
return os.path.realpath(path)
def lexists(self, path):
"""Return True if path refers to an existing path, including
a broken or circular symbolic link.
"""
assert isinstance(path, unicode), path
return os.path.lexists(path)
if pwd is not None:
def get_user_by_uid(self, uid):
"""Return the username associated with user id.
If this can't be determined return raw uid instead.
On Windows just return "owner".
"""
try:
return pwd.getpwuid(uid).pw_name
except KeyError:
return uid
else:
def get_user_by_uid(self, uid):
return "owner"
if grp is not None:
def get_group_by_gid(self, gid):
"""Return the groupname associated with group id.
If this can't be determined return raw gid instead.
On Windows just return "group".
"""
try:
return grp.getgrgid(gid).gr_name
except KeyError:
return gid
else:
def get_group_by_gid(self, gid):
return "group"
# --- Listing utilities
def get_list_dir(self, path):
""""Return an iterator object that yields a directory listing
in a form suitable for LIST command.
"""
assert isinstance(path, unicode), path
if self.isdir(path):
listing = self.listdir(path)
try:
listing.sort()
except UnicodeDecodeError:
# (Python 2 only) might happen on filesystem not
# supporting UTF8 meaning os.listdir() returned a list
# of mixed bytes and unicode strings:
# http://goo.gl/6DLHD
# http://bugs.python.org/issue683592
pass
return self.format_list(path, listing)
# if path is a file or a symlink we return information about it
else:
basedir, filename = os.path.split(path)
self.lstat(path) # raise exc in case of problems
return self.format_list(basedir, [filename])
def format_list(self, basedir, listing, ignore_err=True):
"""Return an iterator object that yields the entries of given
directory emulating the "/bin/ls -lA" UNIX command output.
- (str) basedir: the absolute dirname.
- (list) listing: the names of the entries in basedir
- (bool) ignore_err: when False raise exception if os.lstat()
call fails.
On platforms which do not support the pwd and grp modules (such
as Windows), ownership is printed as "owner" and "group" as a
default, and number of hard links is always "1". On UNIX
systems, the actual owner, group, and number of links are
printed.
This is how output appears to client:
-rw-rw-rw- 1 owner group 7045120 Sep 02 3:47 music.mp3
drwxrwxrwx 1 owner group 0 Aug 31 18:50 e-books
-rw-rw-rw- 1 owner group 380 Sep 02 3:40 module.py
"""
assert isinstance(basedir, unicode), basedir
if listing:
assert isinstance(listing[0], unicode)
if self.cmd_channel.use_gmt_times:
timefunc = time.gmtime
else:
timefunc = time.localtime
SIX_MONTHS = 180 * 24 * 60 * 60
readlink = getattr(self, 'readlink', None)
now = time.time()
for basename in listing:
if not PY3:
try:
file = os.path.join(basedir, basename)
except UnicodeDecodeError:
# (Python 2 only) might happen on filesystem not
# supporting UTF8 meaning os.listdir() returned a list
# of mixed bytes and unicode strings:
# http://goo.gl/6DLHD
# http://bugs.python.org/issue683592
file = os.path.join(bytes(basedir), bytes(basename))
if not isinstance(basename, unicode):
basename = unicode(basename, 'utf8', 'ignore')
else:
file = os.path.join(basedir, basename)
try:
st = self.lstat(file)
except (OSError, FilesystemError):
if ignore_err:
continue
raise
perms = _filemode(st.st_mode) # permissions
nlinks = st.st_nlink # number of links to inode
if not nlinks: # non-posix system, let's use a bogus value
nlinks = 1
size = st.st_size # file size
uname = self.get_user_by_uid(st.st_uid)
gname = self.get_group_by_gid(st.st_gid)
mtime = timefunc(st.st_mtime)
# if modification time > 6 months shows "month year"
# else "month hh:mm"; this matches proftpd format, see:
# https://github.com/giampaolo/pyftpdlib/issues/187
if (now - st.st_mtime) > SIX_MONTHS:
fmtstr = "%d %Y"
else:
fmtstr = "%d %H:%M"
try:
mtimestr = "%s %s" % (_months_map[mtime.tm_mon],
time.strftime(fmtstr, mtime))
except ValueError:
# It could be raised if last mtime happens to be too
# old (prior to year 1900) in which case we return
# the current time as last mtime.
mtime = timefunc()
mtimestr = "%s %s" % (_months_map[mtime.tm_mon],
time.strftime("%d %H:%M", mtime))
# same as stat.S_ISLNK(st.st_mode) but slighlty faster
islink = (st.st_mode & 61440) == stat.S_IFLNK
if islink and readlink is not None:
# if the file is a symlink, resolve it, e.g.
# "symlink -> realfile"
try:
basename = basename + " -> " + readlink(file)
except (OSError, FilesystemError):
if not ignore_err:
raise
# formatting is matched with proftpd ls output
line = "%s %3s %-8s %-8s %8s %s %s\r\n" % (
perms, nlinks, uname, gname, size, mtimestr, basename)
yield line.encode('utf8', self.cmd_channel.unicode_errors)
def format_mlsx(self, basedir, listing, perms, facts, ignore_err=True):
"""Return an iterator object that yields the entries of a given
directory or of a single file in a form suitable with MLSD and
MLST commands.
Every entry includes a list of "facts" referring the listed
element. See RFC-3659, chapter 7, to see what every single
fact stands for.
- (str) basedir: the absolute dirname.
- (list) listing: the names of the entries in basedir
- (str) perms: the string referencing the user permissions.
- (str) facts: the list of "facts" to be returned.
- (bool) ignore_err: when False raise exception if os.stat()
call fails.
Note that "facts" returned may change depending on the platform
and on what user specified by using the OPTS command.
This is how output could appear to the client issuing
a MLSD request:
type=file;size=156;perm=r;modify=20071029155301;unique=8012; music.mp3
type=dir;size=0;perm=el;modify=20071127230206;unique=801e33; ebooks
type=file;size=211;perm=r;modify=20071103093626;unique=192; module.py
"""
assert isinstance(basedir, unicode), basedir
if listing:
assert isinstance(listing[0], unicode)
if self.cmd_channel.use_gmt_times:
timefunc = time.gmtime
else:
timefunc = time.localtime
permdir = ''.join([x for x in perms if x not in 'arw'])
permfile = ''.join([x for x in perms if x not in 'celmp'])
if ('w' in perms) or ('a' in perms) or ('f' in perms):
permdir += 'c'
if 'd' in perms:
permdir += 'p'
show_type = 'type' in facts
show_perm = 'perm' in facts
show_size = 'size' in facts
show_modify = 'modify' in facts
show_create = 'create' in facts
show_mode = 'unix.mode' in facts
show_uid = 'unix.uid' in facts
show_gid = 'unix.gid' in facts
show_unique = 'unique' in facts
for basename in listing:
retfacts = dict()
if not PY3:
try:
file = os.path.join(basedir, basename)
except UnicodeDecodeError:
# (Python 2 only) might happen on filesystem not
# supporting UTF8 meaning os.listdir() returned a list
# of mixed bytes and unicode strings:
# http://goo.gl/6DLHD
# http://bugs.python.org/issue683592
file = os.path.join(bytes(basedir), bytes(basename))
if not isinstance(basename, unicode):
basename = unicode(basename, 'utf8', 'ignore')
else:
file = os.path.join(basedir, basename)
# in order to properly implement 'unique' fact (RFC-3659,
# chapter 7.5.2) we are supposed to follow symlinks, hence
# use os.stat() instead of os.lstat()
try:
st = self.stat(file)
except (OSError, FilesystemError):
if ignore_err:
continue
raise
# type + perm
# same as stat.S_ISDIR(st.st_mode) but slightly faster
isdir = (st.st_mode & 61440) == stat.S_IFDIR
if isdir:
if show_type:
if basename == '.':
retfacts['type'] = 'cdir'
elif basename == '..':
retfacts['type'] = 'pdir'
else:
retfacts['type'] = 'dir'
if show_perm:
retfacts['perm'] = permdir
else:
if show_type:
retfacts['type'] = 'file'
if show_perm:
retfacts['perm'] = permfile
if show_size:
retfacts['size'] = st.st_size # file size
# last modification time
if show_modify:
try:
retfacts['modify'] = time.strftime("%Y%m%d%H%M%S",
timefunc(st.st_mtime))
# it could be raised if last mtime happens to be too old
# (prior to year 1900)
except ValueError:
pass
if show_create:
# on Windows we can provide also the creation time
try:
retfacts['create'] = time.strftime("%Y%m%d%H%M%S",
timefunc(st.st_ctime))
except ValueError:
pass
# UNIX only
if show_mode:
retfacts['unix.mode'] = oct(st.st_mode & 511)
if show_uid:
retfacts['unix.uid'] = st.st_uid
if show_gid:
retfacts['unix.gid'] = st.st_gid
# We provide unique fact (see RFC-3659, chapter 7.5.2) on
# posix platforms only; we get it by mixing st_dev and
# st_ino values which should be enough for granting an
# uniqueness for the file listed.
# The same approach is used by pure-ftpd.
# Implementors who want to provide unique fact on other
# platforms should use some platform-specific method (e.g.
# on Windows NTFS filesystems MTF records could be used).
if show_unique:
retfacts['unique'] = "%xg%x" % (st.st_dev, st.st_ino)
# facts can be in any order but we sort them by name
factstring = "".join(["%s=%s;" % (x, retfacts[x])
for x in sorted(retfacts.keys())])
line = "%s %s\r\n" % (factstring, basename)
yield line.encode('utf8', self.cmd_channel.unicode_errors)
# ===================================================================
# --- platform specific implementation
# ===================================================================
if os.name == 'posix':
__all__.append('UnixFilesystem')
class UnixFilesystem(AbstractedFS):
"""Represents the real UNIX filesystem.
Differently from AbstractedFS the client will login into
/home/<username> and will be able to escape its home directory
and navigate the real filesystem.
"""
def __init__(self, root, cmd_channel):
AbstractedFS.__init__(self, root, cmd_channel)
# initial cwd was set to "/" to emulate a chroot jail
self.cwd = root
def ftp2fs(self, ftppath):
return self.ftpnorm(ftppath)
def fs2ftp(self, fspath):
return fspath
def validpath(self, path):
# validpath was used to check symlinks escaping user home
# directory; this is no longer necessary.
return True
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