linkchecker/linkcheck/dns/dnssec.py
Bastian Kleineidam 3834e56496 Updated dnspython.
2010-10-24 01:02:26 +02:00

119 lines
3.5 KiB
Python

# -*- coding: iso-8859-1 -*-
# Copyright (C) 2003-2007, 2009 Nominum, Inc.
#
# Permission to use, copy, modify, and distribute this software and its
# documentation for any purpose with or without fee is hereby granted,
# provided that the above copyright notice and this permission notice
# appear in all copies.
#
# THE SOFTWARE IS PROVIDED "AS IS" AND NOMINUM DISCLAIMS ALL WARRANTIES
# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL NOMINUM BE LIABLE FOR
# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
# OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
"""Common DNSSEC-related functions and constants."""
import linkcheck.dns.name
import linkcheck.dns.rdata
import linkcheck.dns.rdatatype
import linkcheck.dns.rdataclass
RSAMD5 = 1
DH = 2
DSA = 3
ECC = 4
RSASHA1 = 5
DSANSEC3SHA1 = 6
RSASHA1NSEC3SHA1 = 7
RSASHA256 = 8
RSASHA512 = 10
INDIRECT = 252
PRIVATEDNS = 253
PRIVATEOID = 254
_algorithm_by_text = {
'RSAMD5' : RSAMD5,
'DH' : DH,
'DSA' : DSA,
'ECC' : ECC,
'RSASHA1' : RSASHA1,
'DSANSEC3SHA1' : DSANSEC3SHA1,
'RSASHA1NSEC3SHA1' : RSASHA1NSEC3SHA1,
'RSASHA256' : RSASHA256,
'RSASHA512' : RSASHA512,
'INDIRECT' : INDIRECT,
'PRIVATEDNS' : PRIVATEDNS,
'PRIVATEOID' : PRIVATEOID,
}
# We construct the inverse mapping programmatically to ensure that we
# cannot make any mistakes (e.g. omissions, cut-and-paste errors) that
# would cause the mapping not to be true inverse.
_algorithm_by_value = dict([(y, x) for x, y in _algorithm_by_text.iteritems()])
class UnknownAlgorithm(StandardError):
"""Raised if an algorithm is unknown."""
pass
def algorithm_from_text(text):
"""Convert text into a DNSSEC algorithm value
@rtype: int"""
value = _algorithm_by_text.get(text.upper())
if value is None:
value = int(text)
return value
def algorithm_to_text(value):
"""Convert a DNSSEC algorithm value to text
@rtype: string"""
text = _algorithm_by_value.get(value)
if text is None:
text = str(value)
return text
def _to_rdata(record):
from cStringIO import StringIO
s = StringIO()
record.to_wire(s)
return s.getvalue()
def key_id(key):
rdata = _to_rdata(key)
if key.algorithm == RSAMD5:
return (ord(rdata[-3]) << 8) + ord(rdata[-2])
else:
total = 0
for i in range(len(rdata) / 2):
total += (ord(rdata[2 * i]) << 8) + ord(rdata[2 * i + 1])
if len(rdata) % 2 != 0:
total += ord(rdata[len(rdata) - 1]) << 8
total += ((total >> 16) & 0xffff);
return total & 0xffff
def make_ds(name, key, algorithm):
import hashlib
import struct
if algorithm.upper() == 'SHA1':
dsalg = 1
hash = hashlib.sha1()
elif algorithm.upper() == 'SHA256':
dsalg = 2
hash = hashlib.sha256()
else:
raise ValueError, 'unsupported algorithm "%s"' % algorithm
if isinstance(name, basestring):
name = linkcheck.dns.name.from_text(name)
hash.update(name.canonicalize().to_wire())
hash.update(_to_rdata(key))
digest = hash.digest()
dsrdata = struct.pack("!HBB", key_id(key), key.algorithm, dsalg) + digest
return linkcheck.dns.rdata.from_wire(linkcheck.dns.rdataclass.IN,
linkcheck.dns.rdatatype.DS, dsrdata, 0, len(dsrdata))