mirror of
https://github.com/morpheus65535/bazarr
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234 lines
7.5 KiB
Python
234 lines
7.5 KiB
Python
# Copyright (C) 2001-2007, 2009-2011 Nominum, Inc.
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#
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# Permission to use, copy, modify, and distribute this software and its
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# documentation for any purpose with or without fee is hereby granted,
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# provided that the above copyright notice and this permission notice
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# appear in all copies.
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#
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# THE SOFTWARE IS PROVIDED "AS IS" AND NOMINUM DISCLAIMS ALL WARRANTIES
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# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL NOMINUM BE LIABLE FOR
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# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
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# OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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"""DNS TSIG support."""
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import hmac
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import struct
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import dns.exception
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import dns.hash
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import dns.rdataclass
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import dns.name
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from ._compat import long, string_types, text_type
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class BadTime(dns.exception.DNSException):
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"""The current time is not within the TSIG's validity time."""
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class BadSignature(dns.exception.DNSException):
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"""The TSIG signature fails to verify."""
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class PeerError(dns.exception.DNSException):
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"""Base class for all TSIG errors generated by the remote peer"""
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class PeerBadKey(PeerError):
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"""The peer didn't know the key we used"""
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class PeerBadSignature(PeerError):
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"""The peer didn't like the signature we sent"""
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class PeerBadTime(PeerError):
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"""The peer didn't like the time we sent"""
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class PeerBadTruncation(PeerError):
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"""The peer didn't like amount of truncation in the TSIG we sent"""
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# TSIG Algorithms
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HMAC_MD5 = dns.name.from_text("HMAC-MD5.SIG-ALG.REG.INT")
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HMAC_SHA1 = dns.name.from_text("hmac-sha1")
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HMAC_SHA224 = dns.name.from_text("hmac-sha224")
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HMAC_SHA256 = dns.name.from_text("hmac-sha256")
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HMAC_SHA384 = dns.name.from_text("hmac-sha384")
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HMAC_SHA512 = dns.name.from_text("hmac-sha512")
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_hashes = {
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HMAC_SHA224: 'SHA224',
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HMAC_SHA256: 'SHA256',
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HMAC_SHA384: 'SHA384',
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HMAC_SHA512: 'SHA512',
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HMAC_SHA1: 'SHA1',
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HMAC_MD5: 'MD5',
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}
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default_algorithm = HMAC_MD5
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BADSIG = 16
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BADKEY = 17
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BADTIME = 18
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BADTRUNC = 22
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def sign(wire, keyname, secret, time, fudge, original_id, error,
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other_data, request_mac, ctx=None, multi=False, first=True,
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algorithm=default_algorithm):
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"""Return a (tsig_rdata, mac, ctx) tuple containing the HMAC TSIG rdata
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for the input parameters, the HMAC MAC calculated by applying the
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TSIG signature algorithm, and the TSIG digest context.
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@rtype: (string, string, hmac.HMAC object)
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@raises ValueError: I{other_data} is too long
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@raises NotImplementedError: I{algorithm} is not supported
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"""
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if isinstance(other_data, text_type):
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other_data = other_data.encode()
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(algorithm_name, digestmod) = get_algorithm(algorithm)
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if first:
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ctx = hmac.new(secret, digestmod=digestmod)
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ml = len(request_mac)
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if ml > 0:
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ctx.update(struct.pack('!H', ml))
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ctx.update(request_mac)
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id = struct.pack('!H', original_id)
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ctx.update(id)
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ctx.update(wire[2:])
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if first:
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ctx.update(keyname.to_digestable())
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ctx.update(struct.pack('!H', dns.rdataclass.ANY))
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ctx.update(struct.pack('!I', 0))
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long_time = time + long(0)
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upper_time = (long_time >> 32) & long(0xffff)
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lower_time = long_time & long(0xffffffff)
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time_mac = struct.pack('!HIH', upper_time, lower_time, fudge)
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pre_mac = algorithm_name + time_mac
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ol = len(other_data)
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if ol > 65535:
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raise ValueError('TSIG Other Data is > 65535 bytes')
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post_mac = struct.pack('!HH', error, ol) + other_data
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if first:
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ctx.update(pre_mac)
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ctx.update(post_mac)
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else:
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ctx.update(time_mac)
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mac = ctx.digest()
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mpack = struct.pack('!H', len(mac))
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tsig_rdata = pre_mac + mpack + mac + id + post_mac
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if multi:
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ctx = hmac.new(secret, digestmod=digestmod)
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ml = len(mac)
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ctx.update(struct.pack('!H', ml))
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ctx.update(mac)
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else:
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ctx = None
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return (tsig_rdata, mac, ctx)
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def hmac_md5(wire, keyname, secret, time, fudge, original_id, error,
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other_data, request_mac, ctx=None, multi=False, first=True,
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algorithm=default_algorithm):
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return sign(wire, keyname, secret, time, fudge, original_id, error,
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other_data, request_mac, ctx, multi, first, algorithm)
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def validate(wire, keyname, secret, now, request_mac, tsig_start, tsig_rdata,
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tsig_rdlen, ctx=None, multi=False, first=True):
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"""Validate the specified TSIG rdata against the other input parameters.
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@raises FormError: The TSIG is badly formed.
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@raises BadTime: There is too much time skew between the client and the
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server.
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@raises BadSignature: The TSIG signature did not validate
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@rtype: hmac.HMAC object"""
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(adcount,) = struct.unpack("!H", wire[10:12])
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if adcount == 0:
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raise dns.exception.FormError
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adcount -= 1
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new_wire = wire[0:10] + struct.pack("!H", adcount) + wire[12:tsig_start]
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current = tsig_rdata
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(aname, used) = dns.name.from_wire(wire, current)
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current = current + used
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(upper_time, lower_time, fudge, mac_size) = \
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struct.unpack("!HIHH", wire[current:current + 10])
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time = ((upper_time + long(0)) << 32) + (lower_time + long(0))
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current += 10
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mac = wire[current:current + mac_size]
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current += mac_size
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(original_id, error, other_size) = \
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struct.unpack("!HHH", wire[current:current + 6])
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current += 6
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other_data = wire[current:current + other_size]
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current += other_size
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if current != tsig_rdata + tsig_rdlen:
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raise dns.exception.FormError
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if error != 0:
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if error == BADSIG:
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raise PeerBadSignature
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elif error == BADKEY:
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raise PeerBadKey
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elif error == BADTIME:
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raise PeerBadTime
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elif error == BADTRUNC:
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raise PeerBadTruncation
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else:
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raise PeerError('unknown TSIG error code %d' % error)
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time_low = time - fudge
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time_high = time + fudge
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if now < time_low or now > time_high:
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raise BadTime
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(junk, our_mac, ctx) = sign(new_wire, keyname, secret, time, fudge,
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original_id, error, other_data,
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request_mac, ctx, multi, first, aname)
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if our_mac != mac:
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raise BadSignature
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return ctx
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def get_algorithm(algorithm):
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"""Returns the wire format string and the hash module to use for the
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specified TSIG algorithm
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@rtype: (string, hash constructor)
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@raises NotImplementedError: I{algorithm} is not supported
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"""
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if isinstance(algorithm, string_types):
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algorithm = dns.name.from_text(algorithm)
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try:
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return (algorithm.to_digestable(), dns.hash.hashes[_hashes[algorithm]])
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except KeyError:
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raise NotImplementedError("TSIG algorithm " + str(algorithm) +
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" is not supported")
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def get_algorithm_and_mac(wire, tsig_rdata, tsig_rdlen):
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"""Return the tsig algorithm for the specified tsig_rdata
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@raises FormError: The TSIG is badly formed.
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"""
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current = tsig_rdata
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(aname, used) = dns.name.from_wire(wire, current)
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current = current + used
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(upper_time, lower_time, fudge, mac_size) = \
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struct.unpack("!HIHH", wire[current:current + 10])
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current += 10
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mac = wire[current:current + mac_size]
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current += mac_size
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if current > tsig_rdata + tsig_rdlen:
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raise dns.exception.FormError
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return (aname, mac)
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