352 lines
14 KiB
Python
352 lines
14 KiB
Python
# 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.
|
|
|
|
"""
|
|
Common API for all public keys.
|
|
"""
|
|
|
|
import base64
|
|
from binascii import hexlify, unhexlify
|
|
import os
|
|
|
|
from Crypto.Hash import MD5
|
|
from Crypto.Cipher import DES3, AES
|
|
|
|
from paramiko import util
|
|
from paramiko.common import o600, rng, zero_byte
|
|
from paramiko.py3compat import u, encodebytes, decodebytes, b
|
|
from paramiko.ssh_exception import SSHException, PasswordRequiredException
|
|
|
|
|
|
class PKey (object):
|
|
"""
|
|
Base class for public keys.
|
|
"""
|
|
|
|
# known encryption types for private key files:
|
|
_CIPHER_TABLE = {
|
|
'AES-128-CBC': {'cipher': AES, 'keysize': 16, 'blocksize': 16, 'mode': AES.MODE_CBC},
|
|
'DES-EDE3-CBC': {'cipher': DES3, 'keysize': 24, 'blocksize': 8, 'mode': DES3.MODE_CBC},
|
|
}
|
|
|
|
def __init__(self, msg=None, data=None):
|
|
"""
|
|
Create a new instance of this public key type. If ``msg`` is given,
|
|
the key's public part(s) will be filled in from the message. If
|
|
``data`` is given, the key's public part(s) will be filled in from
|
|
the string.
|
|
|
|
:param .Message msg:
|
|
an optional SSH `.Message` containing a public key of this type.
|
|
:param str data: an optional string containing a public key of this type
|
|
|
|
:raises SSHException:
|
|
if a key cannot be created from the ``data`` or ``msg`` given, or
|
|
no key was passed in.
|
|
"""
|
|
pass
|
|
|
|
def asbytes(self):
|
|
"""
|
|
Return a string of an SSH `.Message` made up of the public part(s) of
|
|
this key. This string is suitable for passing to `__init__` to
|
|
re-create the key object later.
|
|
"""
|
|
return bytes()
|
|
|
|
def __str__(self):
|
|
return self.asbytes()
|
|
|
|
# noinspection PyUnresolvedReferences
|
|
def __cmp__(self, other):
|
|
"""
|
|
Compare this key to another. Returns 0 if this key is equivalent to
|
|
the given key, or non-0 if they are different. Only the public parts
|
|
of the key are compared, so a public key will compare equal to its
|
|
corresponding private key.
|
|
|
|
:param .Pkey other: key to compare to.
|
|
"""
|
|
hs = hash(self)
|
|
ho = hash(other)
|
|
if hs != ho:
|
|
return cmp(hs, ho)
|
|
return cmp(self.asbytes(), other.asbytes())
|
|
|
|
def __eq__(self, other):
|
|
return hash(self) == hash(other)
|
|
|
|
def get_name(self):
|
|
"""
|
|
Return the name of this private key implementation.
|
|
|
|
:return:
|
|
name of this private key type, in SSH terminology, as a `str` (for
|
|
example, ``"ssh-rsa"``).
|
|
"""
|
|
return ''
|
|
|
|
def get_bits(self):
|
|
"""
|
|
Return the number of significant bits in this key. This is useful
|
|
for judging the relative security of a key.
|
|
|
|
:return: bits in the key (as an `int`)
|
|
"""
|
|
return 0
|
|
|
|
def can_sign(self):
|
|
"""
|
|
Return ``True`` if this key has the private part necessary for signing
|
|
data.
|
|
"""
|
|
return False
|
|
|
|
def get_fingerprint(self):
|
|
"""
|
|
Return an MD5 fingerprint of the public part of this key. Nothing
|
|
secret is revealed.
|
|
|
|
:return:
|
|
a 16-byte `string <str>` (binary) of the MD5 fingerprint, in SSH
|
|
format.
|
|
"""
|
|
return MD5.new(self.asbytes()).digest()
|
|
|
|
def get_base64(self):
|
|
"""
|
|
Return a base64 string containing the public part of this key. Nothing
|
|
secret is revealed. This format is compatible with that used to store
|
|
public key files or recognized host keys.
|
|
|
|
:return: a base64 `string <str>` containing the public part of the key.
|
|
"""
|
|
return u(encodebytes(self.asbytes())).replace('\n', '')
|
|
|
|
def sign_ssh_data(self, rng, data):
|
|
"""
|
|
Sign a blob of data with this private key, and return a `.Message`
|
|
representing an SSH signature message.
|
|
|
|
:param .Crypto.Util.rng.RandomPool rng: a secure random number generator.
|
|
:param str data: the data to sign.
|
|
:return: an SSH signature `message <.Message>`.
|
|
"""
|
|
return bytes()
|
|
|
|
def verify_ssh_sig(self, data, msg):
|
|
"""
|
|
Given a blob of data, and an SSH message representing a signature of
|
|
that data, verify that it was signed with this key.
|
|
|
|
:param str data: the data that was signed.
|
|
:param .Message msg: an SSH signature message
|
|
:return:
|
|
``True`` if the signature verifies correctly; ``False`` otherwise.
|
|
"""
|
|
return False
|
|
|
|
def from_private_key_file(cls, filename, password=None):
|
|
"""
|
|
Create a key object by reading a private key file. If the private
|
|
key is encrypted and ``password`` is not ``None``, the given password
|
|
will be used to decrypt the key (otherwise `.PasswordRequiredException`
|
|
is thrown). Through the magic of Python, this factory method will
|
|
exist in all subclasses of PKey (such as `.RSAKey` or `.DSSKey`), but
|
|
is useless on the abstract PKey class.
|
|
|
|
:param str filename: name of the file to read
|
|
:param str password: an optional password to use to decrypt the key file,
|
|
if it's encrypted
|
|
:return: a new `.PKey` based on the given private key
|
|
|
|
:raises IOError: if there was an error reading the file
|
|
:raises PasswordRequiredException: if the private key file is
|
|
encrypted, and ``password`` is ``None``
|
|
:raises SSHException: if the key file is invalid
|
|
"""
|
|
key = cls(filename=filename, password=password)
|
|
return key
|
|
from_private_key_file = classmethod(from_private_key_file)
|
|
|
|
def from_private_key(cls, file_obj, password=None):
|
|
"""
|
|
Create a key object by reading a private key from a file (or file-like)
|
|
object. If the private key is encrypted and ``password`` is not ``None``,
|
|
the given password will be used to decrypt the key (otherwise
|
|
`.PasswordRequiredException` is thrown).
|
|
|
|
:param file file_obj: the file to read from
|
|
:param str password:
|
|
an optional password to use to decrypt the key, if it's encrypted
|
|
:return: a new `.PKey` based on the given private key
|
|
|
|
:raises IOError: if there was an error reading the key
|
|
:raises PasswordRequiredException: if the private key file is encrypted,
|
|
and ``password`` is ``None``
|
|
:raises SSHException: if the key file is invalid
|
|
"""
|
|
key = cls(file_obj=file_obj, password=password)
|
|
return key
|
|
from_private_key = classmethod(from_private_key)
|
|
|
|
def write_private_key_file(self, filename, password=None):
|
|
"""
|
|
Write private key contents into a file. If the password is not
|
|
``None``, the key is encrypted before writing.
|
|
|
|
:param str filename: name of the file to write
|
|
:param str password:
|
|
an optional password to use to encrypt the key file
|
|
|
|
:raises IOError: if there was an error writing the file
|
|
:raises SSHException: if the key is invalid
|
|
"""
|
|
raise Exception('Not implemented in PKey')
|
|
|
|
def write_private_key(self, file_obj, password=None):
|
|
"""
|
|
Write private key contents into a file (or file-like) object. If the
|
|
password is not ``None``, the key is encrypted before writing.
|
|
|
|
:param file file_obj: the file object to write into
|
|
:param str password: an optional password to use to encrypt the key
|
|
|
|
:raises IOError: if there was an error writing to the file
|
|
:raises SSHException: if the key is invalid
|
|
"""
|
|
raise Exception('Not implemented in PKey')
|
|
|
|
def _read_private_key_file(self, tag, filename, password=None):
|
|
"""
|
|
Read an SSH2-format private key file, looking for a string of the type
|
|
``"BEGIN xxx PRIVATE KEY"`` for some ``xxx``, base64-decode the text we
|
|
find, and return it as a string. If the private key is encrypted and
|
|
``password`` is not ``None``, the given password will be used to decrypt
|
|
the key (otherwise `.PasswordRequiredException` is thrown).
|
|
|
|
:param str tag: ``"RSA"`` or ``"DSA"``, the tag used to mark the data block.
|
|
:param str filename: name of the file to read.
|
|
:param str password:
|
|
an optional password to use to decrypt the key file, if it's
|
|
encrypted.
|
|
:return: data blob (`str`) that makes up the private key.
|
|
|
|
:raises IOError: if there was an error reading the file.
|
|
:raises PasswordRequiredException: if the private key file is
|
|
encrypted, and ``password`` is ``None``.
|
|
:raises SSHException: if the key file is invalid.
|
|
"""
|
|
with open(filename, 'r') as f:
|
|
data = self._read_private_key(tag, f, password)
|
|
return data
|
|
|
|
def _read_private_key(self, tag, f, password=None):
|
|
lines = f.readlines()
|
|
start = 0
|
|
while (start < len(lines)) and (lines[start].strip() != '-----BEGIN ' + tag + ' PRIVATE KEY-----'):
|
|
start += 1
|
|
if start >= len(lines):
|
|
raise SSHException('not a valid ' + tag + ' private key file')
|
|
# parse any headers first
|
|
headers = {}
|
|
start += 1
|
|
while start < len(lines):
|
|
l = lines[start].split(': ')
|
|
if len(l) == 1:
|
|
break
|
|
headers[l[0].lower()] = l[1].strip()
|
|
start += 1
|
|
# find end
|
|
end = start
|
|
while (lines[end].strip() != '-----END ' + tag + ' PRIVATE KEY-----') and (end < len(lines)):
|
|
end += 1
|
|
# if we trudged to the end of the file, just try to cope.
|
|
try:
|
|
data = decodebytes(b(''.join(lines[start:end])))
|
|
except base64.binascii.Error as e:
|
|
raise SSHException('base64 decoding error: ' + str(e))
|
|
if 'proc-type' not in headers:
|
|
# unencryped: done
|
|
return data
|
|
# encrypted keyfile: will need a password
|
|
if headers['proc-type'] != '4,ENCRYPTED':
|
|
raise SSHException('Unknown private key structure "%s"' % headers['proc-type'])
|
|
try:
|
|
encryption_type, saltstr = headers['dek-info'].split(',')
|
|
except:
|
|
raise SSHException("Can't parse DEK-info in private key file")
|
|
if encryption_type not in self._CIPHER_TABLE:
|
|
raise SSHException('Unknown private key cipher "%s"' % encryption_type)
|
|
# if no password was passed in, raise an exception pointing out that we need one
|
|
if password is None:
|
|
raise PasswordRequiredException('Private key file is encrypted')
|
|
cipher = self._CIPHER_TABLE[encryption_type]['cipher']
|
|
keysize = self._CIPHER_TABLE[encryption_type]['keysize']
|
|
mode = self._CIPHER_TABLE[encryption_type]['mode']
|
|
salt = unhexlify(b(saltstr))
|
|
key = util.generate_key_bytes(MD5, salt, password, keysize)
|
|
return cipher.new(key, mode, salt).decrypt(data)
|
|
|
|
def _write_private_key_file(self, tag, filename, data, password=None):
|
|
"""
|
|
Write an SSH2-format private key file in a form that can be read by
|
|
paramiko or openssh. If no password is given, the key is written in
|
|
a trivially-encoded format (base64) which is completely insecure. If
|
|
a password is given, DES-EDE3-CBC is used.
|
|
|
|
:param str tag: ``"RSA"`` or ``"DSA"``, the tag used to mark the data block.
|
|
:param file filename: name of the file to write.
|
|
:param str data: data blob that makes up the private key.
|
|
:param str password: an optional password to use to encrypt the file.
|
|
|
|
:raises IOError: if there was an error writing the file.
|
|
"""
|
|
with open(filename, 'w', o600) as f:
|
|
# grrr... the mode doesn't always take hold
|
|
os.chmod(filename, o600)
|
|
self._write_private_key(tag, f, data, password)
|
|
|
|
def _write_private_key(self, tag, f, data, password=None):
|
|
f.write('-----BEGIN %s PRIVATE KEY-----\n' % tag)
|
|
if password is not None:
|
|
# since we only support one cipher here, use it
|
|
cipher_name = list(self._CIPHER_TABLE.keys())[0]
|
|
cipher = self._CIPHER_TABLE[cipher_name]['cipher']
|
|
keysize = self._CIPHER_TABLE[cipher_name]['keysize']
|
|
blocksize = self._CIPHER_TABLE[cipher_name]['blocksize']
|
|
mode = self._CIPHER_TABLE[cipher_name]['mode']
|
|
salt = rng.read(16)
|
|
key = util.generate_key_bytes(MD5, salt, password, keysize)
|
|
if len(data) % blocksize != 0:
|
|
n = blocksize - len(data) % blocksize
|
|
#data += rng.read(n)
|
|
# that would make more sense ^, but it confuses openssh.
|
|
data += zero_byte * n
|
|
data = cipher.new(key, mode, salt).encrypt(data)
|
|
f.write('Proc-Type: 4,ENCRYPTED\n')
|
|
f.write('DEK-Info: %s,%s\n' % (cipher_name, u(hexlify(salt)).upper()))
|
|
f.write('\n')
|
|
s = u(encodebytes(data))
|
|
# re-wrap to 64-char lines
|
|
s = ''.join(s.split('\n'))
|
|
s = '\n'.join([s[i: i + 64] for i in range(0, len(s), 64)])
|
|
f.write(s)
|
|
f.write('\n')
|
|
f.write('-----END %s PRIVATE KEY-----\n' % tag)
|