This file is indexed.

/usr/lib/python2.7/dist-packages/paramiko/dsskey.py is in python-paramiko 1.15.1-1.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

  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)