diff options
Diffstat (limited to 'python')
| -rw-r--r-- | python/vyos/snmpv3_hashgen.py | 109 |
1 files changed, 47 insertions, 62 deletions
diff --git a/python/vyos/snmpv3_hashgen.py b/python/vyos/snmpv3_hashgen.py index a8300353a..324c3274d 100644 --- a/python/vyos/snmpv3_hashgen.py +++ b/python/vyos/snmpv3_hashgen.py @@ -1,65 +1,50 @@ -# Copyright [2017] [Adam Bishop] +# Copyright 2020 VyOS maintainers and contributors <maintainers@vyos.io> # -# Licensed under the Apache License, Version 2.0 (the "License"); -# you may not use this file except in compliance with the License. -# You may obtain a copy of the License at +# This library 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. # -# http://www.apache.org/licenses/LICENSE-2.0 +# This library 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. # -# Unless required by applicable law or agreed to in writing, software -# distributed under the License is distributed on an "AS IS" BASIS, -# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. -# See the License for the specific language governing permissions and -# limitations under the License. - -# Imported from https://github.com/TheMysteriousX/SNMPv3-Hash-Generator - -import hashlib -import string -import secrets - -from itertools import repeat - -P_LEN = 32 -E_LEN = 16 - -class Hashgen(object): - @staticmethod - def md5(bytes): - return hashlib.md5(bytes).digest().hex() - - @staticmethod - def sha1(bytes): - return hashlib.sha1(bytes).digest().hex() - - @staticmethod - def expand(s, l): - reps = l // len(s) + 1 # approximation; worst case: overrun = l + len(s) - return ''.join(list(repeat(s, reps)))[:l] - - @classmethod - def kdf(cls, password): - data = cls.expand(password, 1048576).encode('utf-8') - return hashlib.sha1(data).digest() - - @staticmethod - def random_string(len=P_LEN, alphabet=(string.ascii_letters + string.digits)): - return ''.join(secrets.choice(alphabet) for _ in range(len)) - - @staticmethod - def random_engine(len=E_LEN): - return secrets.token_hex(len) - - @classmethod - def derive_msg(cls, passphrase, engine): - # Parameter derivation รก la rfc3414 - Ku = cls.kdf(passphrase) - E = bytearray.fromhex(engine) - - return b''.join([Ku, E, Ku]) - - # Define available hash algorithms - algs = { - 'sha1': sha1, - 'md5': md5, - } +# You should have received a copy of the GNU Lesser General Public +# License along with this library. If not, see <http://www.gnu.org/licenses/>. + +# Documentation / Inspiration +# - https://tools.ietf.org/html/rfc3414#appendix-A.3 +# - https://github.com/TheMysteriousX/SNMPv3-Hash-Generator + +key_length = 1048576 + +def random(l): + # os.urandom(8) returns 8 bytes of random data + import os + from binascii import hexlify + return hexlify(os.urandom(l)).decode('utf-8') + +def expand(s, l): + """ repead input string (s) as long as we reach the desired length in bytes """ + from itertools import repeat + reps = l // len(s) + 1 # approximation; worst case: overrun = l + len(s) + return ''.join(list(repeat(s, reps)))[:l].encode('utf-8') + +def plaintext_to_md5(passphrase, engine): + """ Convert input plaintext passphrase to MD5 hashed version usable by net-snmp """ + from hashlib import md5 + tmp = expand(passphrase, key_length) + hash = md5(tmp).digest() + engine = bytearray.fromhex(engine) + out = b''.join([hash, engine, hash]) + return md5(out).digest().hex() + +def plaintext_to_sha1(passphrase, engine): + """ Convert input plaintext passphrase to SHA1hashed version usable by net-snmp """ + from hashlib import sha1 + tmp = expand(passphrase, key_length) + hash = sha1(tmp).digest() + engine = bytearray.fromhex(engine) + out = b''.join([hash, engine, hash]) + return sha1(out).digest().hex() |