# Copyright (C) 2003-2007 Robey Pointer <robeypointer@gmail.com>
#
# This file is part of paramiko.
#
# Paramiko is free software; you can redistribute it and/or modify it under the
# terms of the GNU Lesser General Public License as published by the Free
# Software Foundation; either version 2.1 of the License, or (at your option)
# any later version.
#
# Paramiko is distrubuted 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 Lesser General Public License for more
# details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with Paramiko; if not, write to the Free Software Foundation, Inc.,
# 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
"""
Useful functions used by the rest of paramiko.
"""
from __future__ import generators
import array
from binascii import hexlify, unhexlify
import errno
import sys
import struct
import traceback
import threading
from paramiko.common import *
from paramiko.config import SSHConfig
# Change by RogerB - python < 2.3 doesn't have enumerate so we implement it
if sys.version_info < (2,3):
class enumerate:
def __init__ (self, sequence):
self.sequence = sequence
def __iter__ (self):
count = 0
for item in self.sequence:
yield (count, item)
count += 1
def inflate_long(s, always_positive=False):
"turns a normalized byte string into a long-int (adapted from Crypto.Util.number)"
out = 0L
negative = 0
if not always_positive and (len(s) > 0) and (ord(s[0]) >= 0x80):
negative = 1
if len(s) % 4:
filler = '\x00'
if negative:
filler = '\xff'
s = filler * (4 - len(s) % 4) + s
for i in range(0, len(s), 4):
out = (out << 32) + struct.unpack('>I', s[i:i+4])[0]
if negative:
out -= (1L << (8 * len(s)))
return out
def deflate_long(n, add_sign_padding=True):
"turns a long-int into a normalized byte string (adapted from Crypto.Util.number)"
# after much testing, this algorithm was deemed to be the fastest
s = ''
n = long(n)
while (n != 0) and (n != -1):
s = struct.pack('>I', n & 0xffffffffL) + s
n = n >> 32
# strip off leading zeros, FFs
for i in enumerate(s):
if (n == 0) and (i[1] != '\000'):
break
if (n == -1) and (i[1] != '\xff'):
break
else:
# degenerate case, n was either 0 or -1
i = (0,)
if n == 0:
s = '\000'
else:
s = '\xff'
s = s[i[0]:]
if add_sign_padding:
if (n == 0) and (ord(s[0]) >= 0x80):
s = '\x00' + s
if (n == -1) and (ord(s[0]) < 0x80):
s = '\xff' + s
return s
def format_binary_weird(data):
out = ''
for i in enumerate(data):
out += '%02X' % ord(i[1])
if i[0] % 2:
out += ' '
if i[0] % 16 == 15:
out += '\n'
return out
def format_binary(data, prefix=''):
x = 0
out = []
while len(data) > x + 16:
out.append(format_binary_line(data[x:x+16]))
x += 16
if x < len(data):
out.append(format_binary_line(data[x:]))
return [prefix + x for x in out]
def format_binary_line(data):
left = ' '.join(['%02X' % ord(c) for c in data])
right = ''.join([('.%c..' % c)[(ord(c)+63)//95] for c in data])
return '%-50s %s' % (left, right)
def hexify(s):
return hexlify(s).upper()
def unhexify(s):
return unhexlify(s)
def safe_string(s):
out = ''
for c in s:
if (ord(c) >= 32) and (ord(c) <= 127):
out += c
else:
out += '%%%02X' % ord(c)
return out
# ''.join([['%%%02X' % ord(c), c][(ord(c) >= 32) and (ord(c) <= 127)] for c in s])
def bit_length(n):
norm = deflate_long(n, 0)
hbyte = ord(norm[0])
if hbyte == 0:
return 1
bitlen = len(norm) * 8
while not (hbyte & 0x80):
hbyte <<= 1
bitlen -= 1
return bitlen
def tb_strings():
return ''.join(traceback.format_exception(*sys.exc_info())).split('\n')
def generate_key_bytes(hashclass, salt, key, nbytes):
"""
Given a password, passphrase, or other human-source key, scramble it
through a secure hash into some keyworthy bytes. This specific algorithm
is used for encrypting/decrypting private key files.
@param hashclass: class from L{Crypto.Hash} that can be used as a secure
hashing function (like C{MD5} or C{SHA}).
@type hashclass: L{Crypto.Hash}
@param salt: data to salt the hash with.
@type salt: string
@param key: human-entered password or passphrase.
@type key: string
@param nbytes: number of bytes to generate.
@type nbytes: int
@return: key data
@rtype: string
"""
keydata = ''
digest = ''
if len(salt) > 8:
salt = salt[:8]
while nbytes > 0:
hash_obj = hashclass.new()
if len(digest) > 0:
hash_obj.update(digest)
hash_obj.update(key)
hash_obj.update(salt)
digest = hash_obj.digest()
size = min(nbytes, len(digest))
keydata += digest[:size]
nbytes -= size
return keydata
def load_host_keys(filename):
"""
Read a file of known SSH host keys, in the format used by openssh, and
return a compound dict of C{hostname -> keytype ->} L{PKey <paramiko.pkey.PKey>}.
The hostname may be an IP address or DNS name. The keytype will be either
C{"ssh-rsa"} or C{"ssh-dss"}.
This type of file unfortunately doesn't exist on Windows, but on posix,
it will usually be stored in C{os.path.expanduser("~/.ssh/known_hosts")}.
Since 1.5.3, this is just a wrapper around L{HostKeys}.
@param filename: name of the file to read host keys from
@type filename: str
@return: dict of host keys, indexed by hostname and then keytype
@rtype: dict(hostname, dict(keytype, L{PKey <paramiko.pkey.PKey>}))
"""
from paramiko.hostkeys import HostKeys
return HostKeys(filename)
def parse_ssh_config(file_obj):
"""
Provided only as a backward-compatible wrapper around L{SSHConfig}.
"""
config = SSHConfig()
config.parse(file_obj)
return config
def lookup_ssh_host_config(hostname, config):
"""
Provided only as a backward-compatible wrapper around L{SSHConfig}.
"""
return config.lookup(hostname)
def mod_inverse(x, m):
# it's crazy how small python can make this function.
u1, u2, u3 = 1, 0, m
v1, v2, v3 = 0, 1, x
while v3 > 0:
q = u3 // v3
u1, v1 = v1, u1 - v1 * q
u2, v2 = v2, u2 - v2 * q
u3, v3 = v3, u3 - v3 * q
if u2 < 0:
u2 += m
return u2
_g_thread_ids = {}
_g_thread_counter = 0
_g_thread_lock = threading.Lock()
def get_thread_id():
global _g_thread_ids, _g_thread_counter, _g_thread_lock
tid = id(threading.currentThread())
try:
return _g_thread_ids[tid]
except KeyError:
_g_thread_lock.acquire()
try:
_g_thread_counter += 1
ret = _g_thread_ids[tid] = _g_thread_counter
finally:
_g_thread_lock.release()
return ret
def log_to_file(filename, level=DEBUG):
"send paramiko logs to a logfile, if they're not already going somewhere"
l = logging.getLogger("paramiko")
if len(l.handlers) > 0:
return
l.setLevel(level)
f = open(filename, 'w')
lh = logging.StreamHandler(f)
lh.setFormatter(logging.Formatter('%(levelname)-.3s [%(asctime)s.%(msecs)03d] thr=%(_threadid)-3d %(name)s: %(message)s',
'%Y%m%d-%H:%M:%S'))
l.addHandler(lh)
# make only one filter object, so it doesn't get applied more than once
class PFilter (object):
def filter(self, record):
record._threadid = get_thread_id()
return True
_pfilter = PFilter()
def get_logger(name):
l = logging.getLogger(name)
l.addFilter(_pfilter)
return l
def retry_on_signal(function):
"""Retries function until it doesn't raise an EINTR error"""
while True:
try:
return function()
except EnvironmentError, e:
if e.errno != errno.EINTR:
raise
class Counter (object):
"""Stateful counter for CTR mode crypto"""
def __init__(self, nbits, initial_value=1L, overflow=0L):
self.blocksize = nbits / 8
self.overflow = overflow
# start with value - 1 so we don't have to store intermediate values when counting
# could the iv be 0?
if initial_value == 0:
self.value = array.array('c', '\xFF' * self.blocksize)
else:
x = deflate_long(initial_value - 1, add_sign_padding=False)
self.value = array.array('c', '\x00' * (self.blocksize - len(x)) + x)
def __call__(self):
"""Increament the counter and return the new value"""
i = self.blocksize - 1
while i > -1:
c = self.value[i] = chr((ord(self.value[i]) + 1) % 256)
if c != '\x00':
return self.value.tostring()
i -= 1
# counter reset
x = deflate_long(self.overflow, add_sign_padding=False)
self.value = array.array('c', '\x00' * (self.blocksize - len(x)) + x)
return self.value.tostring()
def new(cls, nbits, initial_value=1L, overflow=0L):
return cls(nbits, initial_value=initial_value, overflow=overflow)
new = classmethod(new)