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koboi137 Update error 18f3540 May 17, 2018
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#!/usr/bin/env python
# Copyright (C) 2012, Dhiru Kholia <dhiru@openwall.com>
# Copyright (C) 2015, Dhiru Kholia <dhiru@openwall.com>
#
# Modified for JtR
#
# Copyright (C) 2011, Jeff Forcier <jeff@bitprophet.org>
#
# This file is part of ssh.
#
# 'ssh' 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.
#
# 'ssh' 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 'ssh'; if not, write to the Free Software Foundation, Inc.,
# 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
import base64
import sys
import binascii
from struct import unpack
DES3 = 0
AES = 1
AES_256 = 2
# 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"},
'AES-256-CBC': {'cipher': AES_256, 'keysize': 32, 'blocksize': 16, 'mode': "AES.MODE_CBC"},
'AES-192-CBC': {'cipher': AES, 'keysize': 24, 'blocksize': 16, 'mode': "AES.MODE_CBC"},
}
def read_private_key(filename):
"""
Read an SSH2-format private key file, looking for a string of the type
C{"BEGIN xxx PRIVATE KEY"} for some C{xxx}, base64-decode the text we
find, and return it as a string.
"""
try:
f = open(filename, 'r')
except IOError:
e = sys.exc_info()[1]
sys.stdout.write("%s\n" % str(e))
return
lines = f.readlines()
all_lines = ''.join(lines)
ktype = -1
tag = None
if "BEGIN RSA PRIVATE" in all_lines:
tag = "RSA"
ktype = 0
elif "-----BEGIN OPENSSH PRIVATE KEY-----" in all_lines:
# new private key format for OpenSSH (automatically enabled for
# keys using ed25519 signatures), ed25519 stuff is not supported
# yet!
ktype = 2 # bcrypt pbkdf + aes-256-cbc
tag = "OPENSSH"
elif "-----BEGIN DSA PRIVATE KEY-----" in all_lines:
ktype = 1
tag = "DSA"
elif "-----BEGIN EC PRIVATE KEY-----" in all_lines:
ktype = 3
tag = "EC"
if not tag:
sys.stderr.write("[%s] couldn't parse keyfile\n" % filename)
return
start = 0
while (start < len(lines)) and ((lines[start].strip() != '-----BEGIN ' + tag + ' PRIVATE KEY-----') and (lines[start].strip() != '-----BEGIN OPENSSH PRIVATE KEY-----')):
start += 1
if start >= len(lines):
sys.stderr.write("%s is not a valid private key file\n" % f.name)
return
# 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 = ''.join(lines[start:end]).encode()
data = base64.decodestring(data)
except base64.binascii.Error:
e = sys.exc_info()[1]
raise Exception('base64 decoding error: ' + str(e))
if 'proc-type' not in headers and ktype != 2: # unencrypted key file?
sys.stderr.write("%s has no password!\n" % f.name)
return None
try:
encryption_type, saltstr = headers['dek-info'].split(',')
except:
if ktype != 2:
raise Exception('Can\'t parse DEK-info in private key file')
else:
encryption_type = "AES-256-CBC"
saltstr = "fefe" # dummy value, not used
if encryption_type not in CIPHER_TABLE:
raise Exception('Unknown private key cipher "%s"' % encryption_type)
cipher = CIPHER_TABLE[encryption_type]['cipher']
keysize = CIPHER_TABLE[encryption_type]['keysize']
# mode = CIPHER_TABLE[encryption_type]['mode']
salt = binascii.unhexlify(saltstr)
AUTH_MAGIC = b"openssh-key-v1"
if ktype == 2: # bcrypt_pbkdf format, see "sshkey_private_to_blob2" in sshkey.c
salt_length = 16 # fixed value in sshkey.c
# find offset to salt
offset = 0
if not data.startswith(AUTH_MAGIC):
raise Exception('Missing AUTH_MAGIC!')
offset = offset + len(AUTH_MAGIC) + 1 # sizeof(AUTH_MAGIC)
length = unpack(">I", data[offset:offset+4])[0] # ciphername length
if length > 32: # weak sanity check
raise Exception('Unknown ciphername!')
offset = offset + 4 + length
length = unpack(">I", data[offset:offset+4])[0] # kdfname length
offset = offset + 4 + length
length = unpack(">I", data[offset:offset+4])[0] # kdf length
salt_offset = offset + 4 + 4 # extra "4" to skip over salt length field
# print(salt_offset) # this should be 47, always?
# find offset to check bytes
offset = offset + 4 + length # number of keys
offset = offset + 4 # pubkey blob
length = unpack(">I", data[offset:offset+4])[0] # pubkey length
offset = offset + 4 + length
offset = offset + 4 # skip over length of "encrypted" blob
if offset > len(data):
raise Exception('Internal error in offset calculation!')
ciphertext_begin_offset = offset
saltstr = data[salt_offset:salt_offset+salt_length].encode("hex")
# rounds value appears after salt
rounds_offset = salt_offset + salt_length
rounds = data[rounds_offset: rounds_offset+4]
rounds = unpack(">I", rounds)[0]
if rounds == 0:
rounds == 16
data = binascii.hexlify(data).decode("ascii")
if keysize == 24 and encryption_type == "AES-192-CBC" and (ktype == 0 or ktype == 1): # RSA, DSA keys using AES-192
hashline = "%s:$sshng$%s$%s$%s$%s$%s" % (f.name, 4, len(saltstr) // 2,
saltstr, len(data) // 2, data)
elif keysize == 32 and encryption_type == "AES-256-CBC" and (ktype == 0 or ktype == 1): # RSA, DSA keys using AES-256
hashline = "%s:$sshng$%s$%s$%s$%s$%s" % (f.name, 5, len(saltstr) // 2,
saltstr, len(data) // 2, data)
elif keysize == 24:
hashline = "%s:$sshng$%s$%s$%s$%s$%s" % (f.name, 0, # 0 -> 3DES
len(salt), saltstr, len(data) // 2, data)
elif keysize == 16 and (ktype == 0 or ktype == 1): # RSA, DSA keys using AES-128
hashline = "%s:$sshng$%s$%s$%s$%s$%s" % (f.name, 1, len(saltstr) // 2,
saltstr, len(data) // 2, data)
elif keysize == 16 and ktype == 3: # EC keys using AES-128
hashline = "%s:$sshng$%s$%s$%s$%s$%s" % (f.name, 3, len(saltstr) // 2,
saltstr, len(data) // 2, data)
elif keysize == 32 and ktype == 2: # bcrypt pbkdf + aes-256-cbc
hashline = "%s:$sshng$%s$%s$%s$%s$%s$%d$%d" % (f.name, 2, len(saltstr) // 2,
saltstr, len(data) // 2, data, rounds, ciphertext_begin_offset)
else:
sys.stderr.write("%s uses unsupported cipher, please file a bug!\n" % f.name)
return None
sys.stdout.write("%s\n" % hashline)
if __name__ == "__main__":
if len(sys.argv) < 2:
sys.stdout.write("Usage: %s <RSA/DSA/EC/OpenSSH private key file(s)>\n" %
sys.argv[0])
for filename in sys.argv[1:]:
read_private_key(filename)
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