/usr/lib/python3/dist-packages/paramiko/dsskey.py is in python3-paramiko 1.15.1-1.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 | # 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 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 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.
"""
DSS keys.
"""
import os
from hashlib import sha1
from Crypto.PublicKey import DSA
from paramiko import util
from paramiko.common import zero_byte
from paramiko.py3compat import long
from paramiko.ssh_exception import SSHException
from paramiko.message import Message
from paramiko.ber import BER, BERException
from paramiko.pkey import PKey
class DSSKey (PKey):
"""
Representation of a DSS key which can be used to sign an verify SSH2
data.
"""
def __init__(self, msg=None, data=None, filename=None, password=None, vals=None, file_obj=None):
self.p = None
self.q = None
self.g = None
self.y = None
self.x = None
if file_obj is not None:
self._from_private_key(file_obj, password)
return
if filename is not None:
self._from_private_key_file(filename, password)
return
if (msg is None) and (data is not None):
msg = Message(data)
if vals is not None:
self.p, self.q, self.g, self.y = vals
else:
if msg is None:
raise SSHException('Key object may not be empty')
if msg.get_text() != 'ssh-dss':
raise SSHException('Invalid key')
self.p = msg.get_mpint()
self.q = msg.get_mpint()
self.g = msg.get_mpint()
self.y = msg.get_mpint()
self.size = util.bit_length(self.p)
def asbytes(self):
m = Message()
m.add_string('ssh-dss')
m.add_mpint(self.p)
m.add_mpint(self.q)
m.add_mpint(self.g)
m.add_mpint(self.y)
return m.asbytes()
def __str__(self):
return self.asbytes()
def __hash__(self):
h = hash(self.get_name())
h = h * 37 + hash(self.p)
h = h * 37 + hash(self.q)
h = h * 37 + hash(self.g)
h = h * 37 + hash(self.y)
# h might be a long by now...
return hash(h)
def get_name(self):
return 'ssh-dss'
def get_bits(self):
return self.size
def can_sign(self):
return self.x is not None
def sign_ssh_data(self, data):
digest = sha1(data).digest()
dss = DSA.construct((long(self.y), long(self.g), long(self.p), long(self.q), long(self.x)))
# generate a suitable k
qsize = len(util.deflate_long(self.q, 0))
while True:
k = util.inflate_long(os.urandom(qsize), 1)
if (k > 2) and (k < self.q):
break
r, s = dss.sign(util.inflate_long(digest, 1), k)
m = Message()
m.add_string('ssh-dss')
# apparently, in rare cases, r or s may be shorter than 20 bytes!
rstr = util.deflate_long(r, 0)
sstr = util.deflate_long(s, 0)
if len(rstr) < 20:
rstr = zero_byte * (20 - len(rstr)) + rstr
if len(sstr) < 20:
sstr = zero_byte * (20 - len(sstr)) + sstr
m.add_string(rstr + sstr)
return m
def verify_ssh_sig(self, data, msg):
if len(msg.asbytes()) == 40:
# spies.com bug: signature has no header
sig = msg.asbytes()
else:
kind = msg.get_text()
if kind != 'ssh-dss':
return 0
sig = msg.get_binary()
# pull out (r, s) which are NOT encoded as mpints
sigR = util.inflate_long(sig[:20], 1)
sigS = util.inflate_long(sig[20:], 1)
sigM = util.inflate_long(sha1(data).digest(), 1)
dss = DSA.construct((long(self.y), long(self.g), long(self.p), long(self.q)))
return dss.verify(sigM, (sigR, sigS))
def _encode_key(self):
if self.x is None:
raise SSHException('Not enough key information')
keylist = [0, self.p, self.q, self.g, self.y, self.x]
try:
b = BER()
b.encode(keylist)
except BERException:
raise SSHException('Unable to create ber encoding of key')
return b.asbytes()
def write_private_key_file(self, filename, password=None):
self._write_private_key_file('DSA', filename, self._encode_key(), password)
def write_private_key(self, file_obj, password=None):
self._write_private_key('DSA', file_obj, self._encode_key(), password)
def generate(bits=1024, progress_func=None):
"""
Generate a new private DSS key. This factory function can be used to
generate a new host key or authentication key.
:param int bits: number of bits the generated key should be.
:param function progress_func:
an optional function to call at key points in key generation (used
by ``pyCrypto.PublicKey``).
:return: new `.DSSKey` private key
"""
dsa = DSA.generate(bits, os.urandom, progress_func)
key = DSSKey(vals=(dsa.p, dsa.q, dsa.g, dsa.y))
key.x = dsa.x
return key
generate = staticmethod(generate)
### internals...
def _from_private_key_file(self, filename, password):
data = self._read_private_key_file('DSA', filename, password)
self._decode_key(data)
def _from_private_key(self, file_obj, password):
data = self._read_private_key('DSA', file_obj, password)
self._decode_key(data)
def _decode_key(self, data):
# private key file contains:
# DSAPrivateKey = { version = 0, p, q, g, y, x }
try:
keylist = BER(data).decode()
except BERException as e:
raise SSHException('Unable to parse key file: ' + str(e))
if (type(keylist) is not list) or (len(keylist) < 6) or (keylist[0] != 0):
raise SSHException('not a valid DSA private key file (bad ber encoding)')
self.p = keylist[1]
self.q = keylist[2]
self.g = keylist[3]
self.y = keylist[4]
self.x = keylist[5]
self.size = util.bit_length(self.p)
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