# Copyright (C) Dnspython Contributors, see LICENSE for text of ISC license
# Copyright (C) 2003-2017 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 base64
import contextlib
import functools
import hashlib
import struct
import time
from datetime import datetime
from typing import Callable, Dict, List, Optional, Set, Tuple, Union, cast
import dns._features
import dns.exception
import dns.name
import dns.node
import dns.rdata
import dns.rdataclass
import dns.rdataset
import dns.rdatatype
import dns.rrset
import dns.transaction
import dns.zone
from dns.dnssectypes import Algorithm, DSDigest, NSEC3Hash
from dns.exception import ( # pylint: disable=W0611
AlgorithmKeyMismatch,
DeniedByPolicy,
UnsupportedAlgorithm,
ValidationFailure,
)
from dns.rdtypes.ANY.CDNSKEY import CDNSKEY
from dns.rdtypes.ANY.CDS import CDS
from dns.rdtypes.ANY.DNSKEY import DNSKEY
from dns.rdtypes.ANY.DS import DS
from dns.rdtypes.ANY.NSEC import NSEC, Bitmap
from dns.rdtypes.ANY.NSEC3PARAM import NSEC3PARAM
from dns.rdtypes.ANY.RRSIG import RRSIG, sigtime_to_posixtime
from dns.rdtypes.dnskeybase import Flag
PublicKey = Union[
"GenericPublicKey",
"rsa.RSAPublicKey",
"ec.EllipticCurvePublicKey",
"ed25519.Ed25519PublicKey",
"ed448.Ed448PublicKey",
]
PrivateKey = Union[
"GenericPrivateKey",
"rsa.RSAPrivateKey",
"ec.EllipticCurvePrivateKey",
"ed25519.Ed25519PrivateKey",
"ed448.Ed448PrivateKey",
]
RRsetSigner = Callable[[dns.transaction.Transaction, dns.rrset.RRset], None]
[docs]
def algorithm_from_text(text: str) -> Algorithm:
"""Convert text into a DNSSEC algorithm value.
*text*, a ``str``, the text to convert to into an algorithm value.
Returns an ``int``.
"""
return Algorithm.from_text(text)
[docs]
def algorithm_to_text(value: Union[Algorithm, int]) -> str:
"""Convert a DNSSEC algorithm value to text
*value*, a ``dns.dnssec.Algorithm``.
Returns a ``str``, the name of a DNSSEC algorithm.
"""
return Algorithm.to_text(value)
def to_timestamp(value: Union[datetime, str, float, int]) -> int:
"""Convert various format to a timestamp"""
if isinstance(value, datetime):
return int(value.timestamp())
elif isinstance(value, str):
return sigtime_to_posixtime(value)
elif isinstance(value, float):
return int(value)
elif isinstance(value, int):
return value
else:
raise TypeError("Unsupported timestamp type")
[docs]
def key_id(key: Union[DNSKEY, CDNSKEY]) -> int:
"""Return the key id (a 16-bit number) for the specified key.
*key*, a ``dns.rdtypes.ANY.DNSKEY.DNSKEY``
Returns an ``int`` between 0 and 65535
"""
rdata = key.to_wire()
if key.algorithm == Algorithm.RSAMD5:
return (rdata[-3] << 8) + rdata[-2]
else:
total = 0
for i in range(len(rdata) // 2):
total += (rdata[2 * i] << 8) + rdata[2 * i + 1]
if len(rdata) % 2 != 0:
total += rdata[len(rdata) - 1] << 8
total += (total >> 16) & 0xFFFF
return total & 0xFFFF
class Policy:
def __init__(self):
pass
def ok_to_sign(self, _: DNSKEY) -> bool: # pragma: no cover
return False
def ok_to_validate(self, _: DNSKEY) -> bool: # pragma: no cover
return False
def ok_to_create_ds(self, _: DSDigest) -> bool: # pragma: no cover
return False
def ok_to_validate_ds(self, _: DSDigest) -> bool: # pragma: no cover
return False
class SimpleDeny(Policy):
def __init__(self, deny_sign, deny_validate, deny_create_ds, deny_validate_ds):
super().__init__()
self._deny_sign = deny_sign
self._deny_validate = deny_validate
self._deny_create_ds = deny_create_ds
self._deny_validate_ds = deny_validate_ds
def ok_to_sign(self, key: DNSKEY) -> bool:
return key.algorithm not in self._deny_sign
def ok_to_validate(self, key: DNSKEY) -> bool:
return key.algorithm not in self._deny_validate
def ok_to_create_ds(self, algorithm: DSDigest) -> bool:
return algorithm not in self._deny_create_ds
def ok_to_validate_ds(self, algorithm: DSDigest) -> bool:
return algorithm not in self._deny_validate_ds
rfc_8624_policy = SimpleDeny(
{Algorithm.RSAMD5, Algorithm.DSA, Algorithm.DSANSEC3SHA1, Algorithm.ECCGOST},
{Algorithm.RSAMD5, Algorithm.DSA, Algorithm.DSANSEC3SHA1},
{DSDigest.NULL, DSDigest.SHA1, DSDigest.GOST},
{DSDigest.NULL},
)
allow_all_policy = SimpleDeny(set(), set(), set(), set())
default_policy = rfc_8624_policy
[docs]
def make_ds(
name: Union[dns.name.Name, str],
key: dns.rdata.Rdata,
algorithm: Union[DSDigest, str],
origin: Optional[dns.name.Name] = None,
policy: Optional[Policy] = None,
validating: bool = False,
) -> DS:
"""Create a DS record for a DNSSEC key.
*name*, a ``dns.name.Name`` or ``str``, the owner name of the DS record.
*key*, a ``dns.rdtypes.ANY.DNSKEY.DNSKEY`` or ``dns.rdtypes.ANY.DNSKEY.CDNSKEY``,
the key the DS is about.
*algorithm*, a ``str`` or ``int`` specifying the hash algorithm.
The currently supported hashes are "SHA1", "SHA256", and "SHA384". Case
does not matter for these strings.
*origin*, a ``dns.name.Name`` or ``None``. If *key* is a relative name,
then it will be made absolute using the specified origin.
*policy*, a ``dns.dnssec.Policy`` or ``None``. If ``None``, the default policy,
``dns.dnssec.default_policy`` is used; this policy defaults to that of RFC 8624.
*validating*, a ``bool``. If ``True``, then policy is checked in
validating mode, i.e. "Is it ok to validate using this digest algorithm?".
Otherwise the policy is checked in creating mode, i.e. "Is it ok to create a DS with
this digest algorithm?".
Raises ``UnsupportedAlgorithm`` if the algorithm is unknown.
Raises ``DeniedByPolicy`` if the algorithm is denied by policy.
Returns a ``dns.rdtypes.ANY.DS.DS``
"""
if policy is None:
policy = default_policy
try:
if isinstance(algorithm, str):
algorithm = DSDigest[algorithm.upper()]
except Exception:
raise UnsupportedAlgorithm('unsupported algorithm "%s"' % algorithm)
if validating:
check = policy.ok_to_validate_ds
else:
check = policy.ok_to_create_ds
if not check(algorithm):
raise DeniedByPolicy
if not isinstance(key, (DNSKEY, CDNSKEY)):
raise ValueError("key is not a DNSKEY/CDNSKEY")
if algorithm == DSDigest.SHA1:
dshash = hashlib.sha1()
elif algorithm == DSDigest.SHA256:
dshash = hashlib.sha256()
elif algorithm == DSDigest.SHA384:
dshash = hashlib.sha384()
else:
raise UnsupportedAlgorithm('unsupported algorithm "%s"' % algorithm)
if isinstance(name, str):
name = dns.name.from_text(name, origin)
wire = name.canonicalize().to_wire()
assert wire is not None
dshash.update(wire)
dshash.update(key.to_wire(origin=origin))
digest = dshash.digest()
dsrdata = struct.pack("!HBB", key_id(key), key.algorithm, algorithm) + digest
ds = dns.rdata.from_wire(
dns.rdataclass.IN, dns.rdatatype.DS, dsrdata, 0, len(dsrdata)
)
return cast(DS, ds)
[docs]
def make_cds(
name: Union[dns.name.Name, str],
key: dns.rdata.Rdata,
algorithm: Union[DSDigest, str],
origin: Optional[dns.name.Name] = None,
) -> CDS:
"""Create a CDS record for a DNSSEC key.
*name*, a ``dns.name.Name`` or ``str``, the owner name of the DS record.
*key*, a ``dns.rdtypes.ANY.DNSKEY.DNSKEY`` or ``dns.rdtypes.ANY.DNSKEY.CDNSKEY``,
the key the DS is about.
*algorithm*, a ``str`` or ``int`` specifying the hash algorithm.
The currently supported hashes are "SHA1", "SHA256", and "SHA384". Case
does not matter for these strings.
*origin*, a ``dns.name.Name`` or ``None``. If *key* is a relative name,
then it will be made absolute using the specified origin.
Raises ``UnsupportedAlgorithm`` if the algorithm is unknown.
Returns a ``dns.rdtypes.ANY.DS.CDS``
"""
ds = make_ds(name, key, algorithm, origin)
return CDS(
rdclass=ds.rdclass,
rdtype=dns.rdatatype.CDS,
key_tag=ds.key_tag,
algorithm=ds.algorithm,
digest_type=ds.digest_type,
digest=ds.digest,
)
def _find_candidate_keys(
keys: Dict[dns.name.Name, Union[dns.rdataset.Rdataset, dns.node.Node]], rrsig: RRSIG
) -> Optional[List[DNSKEY]]:
value = keys.get(rrsig.signer)
if isinstance(value, dns.node.Node):
rdataset = value.get_rdataset(dns.rdataclass.IN, dns.rdatatype.DNSKEY)
else:
rdataset = value
if rdataset is None:
return None
return [
cast(DNSKEY, rd)
for rd in rdataset
if rd.algorithm == rrsig.algorithm
and key_id(rd) == rrsig.key_tag
and (rd.flags & Flag.ZONE) == Flag.ZONE # RFC 4034 2.1.1
and rd.protocol == 3 # RFC 4034 2.1.2
]
def _get_rrname_rdataset(
rrset: Union[dns.rrset.RRset, Tuple[dns.name.Name, dns.rdataset.Rdataset]],
) -> Tuple[dns.name.Name, dns.rdataset.Rdataset]:
if isinstance(rrset, tuple):
return rrset[0], rrset[1]
else:
return rrset.name, rrset
def _validate_signature(sig: bytes, data: bytes, key: DNSKEY) -> None:
public_cls = get_algorithm_cls_from_dnskey(key).public_cls
try:
public_key = public_cls.from_dnskey(key)
except ValueError:
raise ValidationFailure("invalid public key")
public_key.verify(sig, data)
def _validate_rrsig(
rrset: Union[dns.rrset.RRset, Tuple[dns.name.Name, dns.rdataset.Rdataset]],
rrsig: RRSIG,
keys: Dict[dns.name.Name, Union[dns.node.Node, dns.rdataset.Rdataset]],
origin: Optional[dns.name.Name] = None,
now: Optional[float] = None,
policy: Optional[Policy] = None,
) -> None:
"""Validate an RRset against a single signature rdata, throwing an
exception if validation is not successful.
*rrset*, the RRset to validate. This can be a
``dns.rrset.RRset`` or a (``dns.name.Name``, ``dns.rdataset.Rdataset``)
tuple.
*rrsig*, a ``dns.rdata.Rdata``, the signature to validate.
*keys*, the key dictionary, used to find the DNSKEY associated
with a given name. The dictionary is keyed by a
``dns.name.Name``, and has ``dns.node.Node`` or
``dns.rdataset.Rdataset`` values.
*origin*, a ``dns.name.Name`` or ``None``, the origin to use for relative
names.
*now*, a ``float`` or ``None``, the time, in seconds since the epoch, to
use as the current time when validating. If ``None``, the actual current
time is used.
*policy*, a ``dns.dnssec.Policy`` or ``None``. If ``None``, the default policy,
``dns.dnssec.default_policy`` is used; this policy defaults to that of RFC 8624.
Raises ``ValidationFailure`` if the signature is expired, not yet valid,
the public key is invalid, the algorithm is unknown, the verification
fails, etc.
Raises ``UnsupportedAlgorithm`` if the algorithm is recognized by
dnspython but not implemented.
"""
if policy is None:
policy = default_policy
candidate_keys = _find_candidate_keys(keys, rrsig)
if candidate_keys is None:
raise ValidationFailure("unknown key")
if now is None:
now = time.time()
if rrsig.expiration < now:
raise ValidationFailure("expired")
if rrsig.inception > now:
raise ValidationFailure("not yet valid")
data = _make_rrsig_signature_data(rrset, rrsig, origin)
for candidate_key in candidate_keys:
if not policy.ok_to_validate(candidate_key):
continue
try:
_validate_signature(rrsig.signature, data, candidate_key)
return
except (InvalidSignature, ValidationFailure):
# this happens on an individual validation failure
continue
# nothing verified -- raise failure:
raise ValidationFailure("verify failure")
def _validate(
rrset: Union[dns.rrset.RRset, Tuple[dns.name.Name, dns.rdataset.Rdataset]],
rrsigset: Union[dns.rrset.RRset, Tuple[dns.name.Name, dns.rdataset.Rdataset]],
keys: Dict[dns.name.Name, Union[dns.node.Node, dns.rdataset.Rdataset]],
origin: Optional[dns.name.Name] = None,
now: Optional[float] = None,
policy: Optional[Policy] = None,
) -> None:
"""Validate an RRset against a signature RRset, throwing an exception
if none of the signatures validate.
*rrset*, the RRset to validate. This can be a
``dns.rrset.RRset`` or a (``dns.name.Name``, ``dns.rdataset.Rdataset``)
tuple.
*rrsigset*, the signature RRset. This can be a
``dns.rrset.RRset`` or a (``dns.name.Name``, ``dns.rdataset.Rdataset``)
tuple.
*keys*, the key dictionary, used to find the DNSKEY associated
with a given name. The dictionary is keyed by a
``dns.name.Name``, and has ``dns.node.Node`` or
``dns.rdataset.Rdataset`` values.
*origin*, a ``dns.name.Name``, the origin to use for relative names;
defaults to None.
*now*, an ``int`` or ``None``, the time, in seconds since the epoch, to
use as the current time when validating. If ``None``, the actual current
time is used.
*policy*, a ``dns.dnssec.Policy`` or ``None``. If ``None``, the default policy,
``dns.dnssec.default_policy`` is used; this policy defaults to that of RFC 8624.
Raises ``ValidationFailure`` if the signature is expired, not yet valid,
the public key is invalid, the algorithm is unknown, the verification
fails, etc.
"""
if policy is None:
policy = default_policy
if isinstance(origin, str):
origin = dns.name.from_text(origin, dns.name.root)
if isinstance(rrset, tuple):
rrname = rrset[0]
else:
rrname = rrset.name
if isinstance(rrsigset, tuple):
rrsigname = rrsigset[0]
rrsigrdataset = rrsigset[1]
else:
rrsigname = rrsigset.name
rrsigrdataset = rrsigset
rrname = rrname.choose_relativity(origin)
rrsigname = rrsigname.choose_relativity(origin)
if rrname != rrsigname:
raise ValidationFailure("owner names do not match")
for rrsig in rrsigrdataset:
if not isinstance(rrsig, RRSIG):
raise ValidationFailure("expected an RRSIG")
try:
_validate_rrsig(rrset, rrsig, keys, origin, now, policy)
return
except (ValidationFailure, UnsupportedAlgorithm):
pass
raise ValidationFailure("no RRSIGs validated")
def _sign(
rrset: Union[dns.rrset.RRset, Tuple[dns.name.Name, dns.rdataset.Rdataset]],
private_key: PrivateKey,
signer: dns.name.Name,
dnskey: DNSKEY,
inception: Optional[Union[datetime, str, int, float]] = None,
expiration: Optional[Union[datetime, str, int, float]] = None,
lifetime: Optional[int] = None,
verify: bool = False,
policy: Optional[Policy] = None,
origin: Optional[dns.name.Name] = None,
) -> RRSIG:
"""Sign RRset using private key.
*rrset*, the RRset to validate. This can be a
``dns.rrset.RRset`` or a (``dns.name.Name``, ``dns.rdataset.Rdataset``)
tuple.
*private_key*, the private key to use for signing, a
``cryptography.hazmat.primitives.asymmetric`` private key class applicable
for DNSSEC.
*signer*, a ``dns.name.Name``, the Signer's name.
*dnskey*, a ``DNSKEY`` matching ``private_key``.
*inception*, a ``datetime``, ``str``, ``int``, ``float`` or ``None``, the
signature inception time. If ``None``, the current time is used. If a ``str``, the
format is "YYYYMMDDHHMMSS" or alternatively the number of seconds since the UNIX
epoch in text form; this is the same the RRSIG rdata's text form.
Values of type `int` or `float` are interpreted as seconds since the UNIX epoch.
*expiration*, a ``datetime``, ``str``, ``int``, ``float`` or ``None``, the signature
expiration time. If ``None``, the expiration time will be the inception time plus
the value of the *lifetime* parameter. See the description of *inception* above
for how the various parameter types are interpreted.
*lifetime*, an ``int`` or ``None``, the signature lifetime in seconds. This
parameter is only meaningful if *expiration* is ``None``.
*verify*, a ``bool``. If set to ``True``, the signer will verify signatures
after they are created; the default is ``False``.
*policy*, a ``dns.dnssec.Policy`` or ``None``. If ``None``, the default policy,
``dns.dnssec.default_policy`` is used; this policy defaults to that of RFC 8624.
*origin*, a ``dns.name.Name`` or ``None``. If ``None``, the default, then all
names in the rrset (including its owner name) must be absolute; otherwise the
specified origin will be used to make names absolute when signing.
Raises ``DeniedByPolicy`` if the signature is denied by policy.
"""
if policy is None:
policy = default_policy
if not policy.ok_to_sign(dnskey):
raise DeniedByPolicy
if isinstance(rrset, tuple):
rdclass = rrset[1].rdclass
rdtype = rrset[1].rdtype
rrname = rrset[0]
original_ttl = rrset[1].ttl
else:
rdclass = rrset.rdclass
rdtype = rrset.rdtype
rrname = rrset.name
original_ttl = rrset.ttl
if inception is not None:
rrsig_inception = to_timestamp(inception)
else:
rrsig_inception = int(time.time())
if expiration is not None:
rrsig_expiration = to_timestamp(expiration)
elif lifetime is not None:
rrsig_expiration = rrsig_inception + lifetime
else:
raise ValueError("expiration or lifetime must be specified")
# Derelativize now because we need a correct labels length for the
# rrsig_template.
if origin is not None:
rrname = rrname.derelativize(origin)
labels = len(rrname) - 1
# Adjust labels appropriately for wildcards.
if rrname.is_wild():
labels -= 1
rrsig_template = RRSIG(
rdclass=rdclass,
rdtype=dns.rdatatype.RRSIG,
type_covered=rdtype,
algorithm=dnskey.algorithm,
labels=labels,
original_ttl=original_ttl,
expiration=rrsig_expiration,
inception=rrsig_inception,
key_tag=key_id(dnskey),
signer=signer,
signature=b"",
)
data = dns.dnssec._make_rrsig_signature_data(rrset, rrsig_template, origin)
if isinstance(private_key, GenericPrivateKey):
signing_key = private_key
else:
try:
private_cls = get_algorithm_cls_from_dnskey(dnskey)
signing_key = private_cls(key=private_key)
except UnsupportedAlgorithm:
raise TypeError("Unsupported key algorithm")
signature = signing_key.sign(data, verify)
return cast(RRSIG, rrsig_template.replace(signature=signature))
def _make_rrsig_signature_data(
rrset: Union[dns.rrset.RRset, Tuple[dns.name.Name, dns.rdataset.Rdataset]],
rrsig: RRSIG,
origin: Optional[dns.name.Name] = None,
) -> bytes:
"""Create signature rdata.
*rrset*, the RRset to sign/validate. This can be a
``dns.rrset.RRset`` or a (``dns.name.Name``, ``dns.rdataset.Rdataset``)
tuple.
*rrsig*, a ``dns.rdata.Rdata``, the signature to validate, or the
signature template used when signing.
*origin*, a ``dns.name.Name`` or ``None``, the origin to use for relative
names.
Raises ``UnsupportedAlgorithm`` if the algorithm is recognized by
dnspython but not implemented.
"""
if isinstance(origin, str):
origin = dns.name.from_text(origin, dns.name.root)
signer = rrsig.signer
if not signer.is_absolute():
if origin is None:
raise ValidationFailure("relative RR name without an origin specified")
signer = signer.derelativize(origin)
# For convenience, allow the rrset to be specified as a (name,
# rdataset) tuple as well as a proper rrset
rrname, rdataset = _get_rrname_rdataset(rrset)
data = b""
data += rrsig.to_wire(origin=signer)[:18]
data += rrsig.signer.to_digestable(signer)
# Derelativize the name before considering labels.
if not rrname.is_absolute():
if origin is None:
raise ValidationFailure("relative RR name without an origin specified")
rrname = rrname.derelativize(origin)
name_len = len(rrname)
if rrname.is_wild() and rrsig.labels != name_len - 2:
raise ValidationFailure("wild owner name has wrong label length")
if name_len - 1 < rrsig.labels:
raise ValidationFailure("owner name longer than RRSIG labels")
elif rrsig.labels < name_len - 1:
suffix = rrname.split(rrsig.labels + 1)[1]
rrname = dns.name.from_text("*", suffix)
rrnamebuf = rrname.to_digestable()
rrfixed = struct.pack("!HHI", rdataset.rdtype, rdataset.rdclass, rrsig.original_ttl)
rdatas = [rdata.to_digestable(origin) for rdata in rdataset]
for rdata in sorted(rdatas):
data += rrnamebuf
data += rrfixed
rrlen = struct.pack("!H", len(rdata))
data += rrlen
data += rdata
return data
def _make_dnskey(
public_key: PublicKey,
algorithm: Union[int, str],
flags: int = Flag.ZONE,
protocol: int = 3,
) -> DNSKEY:
"""Convert a public key to DNSKEY Rdata
*public_key*, a ``PublicKey`` (``GenericPublicKey`` or
``cryptography.hazmat.primitives.asymmetric``) to convert.
*algorithm*, a ``str`` or ``int`` specifying the DNSKEY algorithm.
*flags*: DNSKEY flags field as an integer.
*protocol*: DNSKEY protocol field as an integer.
Raises ``ValueError`` if the specified key algorithm parameters are not
unsupported, ``TypeError`` if the key type is unsupported,
`UnsupportedAlgorithm` if the algorithm is unknown and
`AlgorithmKeyMismatch` if the algorithm does not match the key type.
Return DNSKEY ``Rdata``.
"""
algorithm = Algorithm.make(algorithm)
if isinstance(public_key, GenericPublicKey):
return public_key.to_dnskey(flags=flags, protocol=protocol)
else:
public_cls = get_algorithm_cls(algorithm).public_cls
return public_cls(key=public_key).to_dnskey(flags=flags, protocol=protocol)
def _make_cdnskey(
public_key: PublicKey,
algorithm: Union[int, str],
flags: int = Flag.ZONE,
protocol: int = 3,
) -> CDNSKEY:
"""Convert a public key to CDNSKEY Rdata
*public_key*, the public key to convert, a
``cryptography.hazmat.primitives.asymmetric`` public key class applicable
for DNSSEC.
*algorithm*, a ``str`` or ``int`` specifying the DNSKEY algorithm.
*flags*: DNSKEY flags field as an integer.
*protocol*: DNSKEY protocol field as an integer.
Raises ``ValueError`` if the specified key algorithm parameters are not
unsupported, ``TypeError`` if the key type is unsupported,
`UnsupportedAlgorithm` if the algorithm is unknown and
`AlgorithmKeyMismatch` if the algorithm does not match the key type.
Return CDNSKEY ``Rdata``.
"""
dnskey = _make_dnskey(public_key, algorithm, flags, protocol)
return CDNSKEY(
rdclass=dnskey.rdclass,
rdtype=dns.rdatatype.CDNSKEY,
flags=dnskey.flags,
protocol=dnskey.protocol,
algorithm=dnskey.algorithm,
key=dnskey.key,
)
[docs]
def nsec3_hash(
domain: Union[dns.name.Name, str],
salt: Optional[Union[str, bytes]],
iterations: int,
algorithm: Union[int, str],
) -> str:
"""
Calculate the NSEC3 hash, according to
https://tools.ietf.org/html/rfc5155#section-5
*domain*, a ``dns.name.Name`` or ``str``, the name to hash.
*salt*, a ``str``, ``bytes``, or ``None``, the hash salt. If a
string, it is decoded as a hex string.
*iterations*, an ``int``, the number of iterations.
*algorithm*, a ``str`` or ``int``, the hash algorithm.
The only defined algorithm is SHA1.
Returns a ``str``, the encoded NSEC3 hash.
"""
b32_conversion = str.maketrans(
"ABCDEFGHIJKLMNOPQRSTUVWXYZ234567", "0123456789ABCDEFGHIJKLMNOPQRSTUV"
)
try:
if isinstance(algorithm, str):
algorithm = NSEC3Hash[algorithm.upper()]
except Exception:
raise ValueError("Wrong hash algorithm (only SHA1 is supported)")
if algorithm != NSEC3Hash.SHA1:
raise ValueError("Wrong hash algorithm (only SHA1 is supported)")
if salt is None:
salt_encoded = b""
elif isinstance(salt, str):
if len(salt) % 2 == 0:
salt_encoded = bytes.fromhex(salt)
else:
raise ValueError("Invalid salt length")
else:
salt_encoded = salt
if not isinstance(domain, dns.name.Name):
domain = dns.name.from_text(domain)
domain_encoded = domain.canonicalize().to_wire()
assert domain_encoded is not None
digest = hashlib.sha1(domain_encoded + salt_encoded).digest()
for _ in range(iterations):
digest = hashlib.sha1(digest + salt_encoded).digest()
output = base64.b32encode(digest).decode("utf-8")
output = output.translate(b32_conversion)
return output
[docs]
def make_ds_rdataset(
rrset: Union[dns.rrset.RRset, Tuple[dns.name.Name, dns.rdataset.Rdataset]],
algorithms: Set[Union[DSDigest, str]],
origin: Optional[dns.name.Name] = None,
) -> dns.rdataset.Rdataset:
"""Create a DS record from DNSKEY/CDNSKEY/CDS.
*rrset*, the RRset to create DS Rdataset for. This can be a
``dns.rrset.RRset`` or a (``dns.name.Name``, ``dns.rdataset.Rdataset``)
tuple.
*algorithms*, a set of ``str`` or ``int`` specifying the hash algorithms.
The currently supported hashes are "SHA1", "SHA256", and "SHA384". Case
does not matter for these strings. If the RRset is a CDS, only digest
algorithms matching algorithms are accepted.
*origin*, a ``dns.name.Name`` or ``None``. If `key` is a relative name,
then it will be made absolute using the specified origin.
Raises ``UnsupportedAlgorithm`` if any of the algorithms are unknown and
``ValueError`` if the given RRset is not usable.
Returns a ``dns.rdataset.Rdataset``
"""
rrname, rdataset = _get_rrname_rdataset(rrset)
if rdataset.rdtype not in (
dns.rdatatype.DNSKEY,
dns.rdatatype.CDNSKEY,
dns.rdatatype.CDS,
):
raise ValueError("rrset not a DNSKEY/CDNSKEY/CDS")
_algorithms = set()
for algorithm in algorithms:
try:
if isinstance(algorithm, str):
algorithm = DSDigest[algorithm.upper()]
except Exception:
raise UnsupportedAlgorithm('unsupported algorithm "%s"' % algorithm)
_algorithms.add(algorithm)
if rdataset.rdtype == dns.rdatatype.CDS:
res = []
for rdata in cds_rdataset_to_ds_rdataset(rdataset):
if rdata.digest_type in _algorithms:
res.append(rdata)
if len(res) == 0:
raise ValueError("no acceptable CDS rdata found")
return dns.rdataset.from_rdata_list(rdataset.ttl, res)
res = []
for algorithm in _algorithms:
res.extend(dnskey_rdataset_to_cds_rdataset(rrname, rdataset, algorithm, origin))
return dns.rdataset.from_rdata_list(rdataset.ttl, res)
[docs]
def cds_rdataset_to_ds_rdataset(
rdataset: dns.rdataset.Rdataset,
) -> dns.rdataset.Rdataset:
"""Create a CDS record from DS.
*rdataset*, a ``dns.rdataset.Rdataset``, to create DS Rdataset for.
Raises ``ValueError`` if the rdataset is not CDS.
Returns a ``dns.rdataset.Rdataset``
"""
if rdataset.rdtype != dns.rdatatype.CDS:
raise ValueError("rdataset not a CDS")
res = []
for rdata in rdataset:
res.append(
CDS(
rdclass=rdata.rdclass,
rdtype=dns.rdatatype.DS,
key_tag=rdata.key_tag,
algorithm=rdata.algorithm,
digest_type=rdata.digest_type,
digest=rdata.digest,
)
)
return dns.rdataset.from_rdata_list(rdataset.ttl, res)
[docs]
def dnskey_rdataset_to_cds_rdataset(
name: Union[dns.name.Name, str],
rdataset: dns.rdataset.Rdataset,
algorithm: Union[DSDigest, str],
origin: Optional[dns.name.Name] = None,
) -> dns.rdataset.Rdataset:
"""Create a CDS record from DNSKEY/CDNSKEY.
*name*, a ``dns.name.Name`` or ``str``, the owner name of the CDS record.
*rdataset*, a ``dns.rdataset.Rdataset``, to create DS Rdataset for.
*algorithm*, a ``str`` or ``int`` specifying the hash algorithm.
The currently supported hashes are "SHA1", "SHA256", and "SHA384". Case
does not matter for these strings.
*origin*, a ``dns.name.Name`` or ``None``. If `key` is a relative name,
then it will be made absolute using the specified origin.
Raises ``UnsupportedAlgorithm`` if the algorithm is unknown or
``ValueError`` if the rdataset is not DNSKEY/CDNSKEY.
Returns a ``dns.rdataset.Rdataset``
"""
if rdataset.rdtype not in (dns.rdatatype.DNSKEY, dns.rdatatype.CDNSKEY):
raise ValueError("rdataset not a DNSKEY/CDNSKEY")
res = []
for rdata in rdataset:
res.append(make_cds(name, rdata, algorithm, origin))
return dns.rdataset.from_rdata_list(rdataset.ttl, res)
[docs]
def dnskey_rdataset_to_cdnskey_rdataset(
rdataset: dns.rdataset.Rdataset,
) -> dns.rdataset.Rdataset:
"""Create a CDNSKEY record from DNSKEY.
*rdataset*, a ``dns.rdataset.Rdataset``, to create CDNSKEY Rdataset for.
Returns a ``dns.rdataset.Rdataset``
"""
if rdataset.rdtype != dns.rdatatype.DNSKEY:
raise ValueError("rdataset not a DNSKEY")
res = []
for rdata in rdataset:
res.append(
CDNSKEY(
rdclass=rdataset.rdclass,
rdtype=rdataset.rdtype,
flags=rdata.flags,
protocol=rdata.protocol,
algorithm=rdata.algorithm,
key=rdata.key,
)
)
return dns.rdataset.from_rdata_list(rdataset.ttl, res)
[docs]
def default_rrset_signer(
txn: dns.transaction.Transaction,
rrset: dns.rrset.RRset,
signer: dns.name.Name,
ksks: List[Tuple[PrivateKey, DNSKEY]],
zsks: List[Tuple[PrivateKey, DNSKEY]],
inception: Optional[Union[datetime, str, int, float]] = None,
expiration: Optional[Union[datetime, str, int, float]] = None,
lifetime: Optional[int] = None,
policy: Optional[Policy] = None,
origin: Optional[dns.name.Name] = None,
) -> None:
"""Default RRset signer"""
if rrset.rdtype in set(
[
dns.rdatatype.RdataType.DNSKEY,
dns.rdatatype.RdataType.CDS,
dns.rdatatype.RdataType.CDNSKEY,
]
):
keys = ksks
else:
keys = zsks
for private_key, dnskey in keys:
rrsig = dns.dnssec.sign(
rrset=rrset,
private_key=private_key,
dnskey=dnskey,
inception=inception,
expiration=expiration,
lifetime=lifetime,
signer=signer,
policy=policy,
origin=origin,
)
txn.add(rrset.name, rrset.ttl, rrsig)
[docs]
def sign_zone(
zone: dns.zone.Zone,
txn: Optional[dns.transaction.Transaction] = None,
keys: Optional[List[Tuple[PrivateKey, DNSKEY]]] = None,
add_dnskey: bool = True,
dnskey_ttl: Optional[int] = None,
inception: Optional[Union[datetime, str, int, float]] = None,
expiration: Optional[Union[datetime, str, int, float]] = None,
lifetime: Optional[int] = None,
nsec3: Optional[NSEC3PARAM] = None,
rrset_signer: Optional[RRsetSigner] = None,
policy: Optional[Policy] = None,
) -> None:
"""Sign zone.
*zone*, a ``dns.zone.Zone``, the zone to sign.
*txn*, a ``dns.transaction.Transaction``, an optional transaction to use for
signing.
*keys*, a list of (``PrivateKey``, ``DNSKEY``) tuples, to use for signing. KSK/ZSK
roles are assigned automatically if the SEP flag is used, otherwise all RRsets are
signed by all keys.
*add_dnskey*, a ``bool``. If ``True``, the default, all specified DNSKEYs are
automatically added to the zone on signing.
*dnskey_ttl*, a``int``, specifies the TTL for DNSKEY RRs. If not specified the TTL
of the existing DNSKEY RRset used or the TTL of the SOA RRset.
*inception*, a ``datetime``, ``str``, ``int``, ``float`` or ``None``, the signature
inception time. If ``None``, the current time is used. If a ``str``, the format is
"YYYYMMDDHHMMSS" or alternatively the number of seconds since the UNIX epoch in text
form; this is the same the RRSIG rdata's text form. Values of type `int` or `float`
are interpreted as seconds since the UNIX epoch.
*expiration*, a ``datetime``, ``str``, ``int``, ``float`` or ``None``, the signature
expiration time. If ``None``, the expiration time will be the inception time plus
the value of the *lifetime* parameter. See the description of *inception* above for
how the various parameter types are interpreted.
*lifetime*, an ``int`` or ``None``, the signature lifetime in seconds. This
parameter is only meaningful if *expiration* is ``None``.
*nsec3*, a ``NSEC3PARAM`` Rdata, configures signing using NSEC3. Not yet
implemented.
*rrset_signer*, a ``Callable``, an optional function for signing RRsets. The
function requires two arguments: transaction and RRset. If the not specified,
``dns.dnssec.default_rrset_signer`` will be used.
Returns ``None``.
"""
ksks = []
zsks = []
# if we have both KSKs and ZSKs, split by SEP flag. if not, sign all
# records with all keys
if keys:
for key in keys:
if key[1].flags & Flag.SEP:
ksks.append(key)
else:
zsks.append(key)
if not ksks:
ksks = keys
if not zsks:
zsks = keys
else:
keys = []
if txn:
cm: contextlib.AbstractContextManager = contextlib.nullcontext(txn)
else:
cm = zone.writer()
with cm as _txn:
if add_dnskey:
if dnskey_ttl is None:
dnskey = _txn.get(zone.origin, dns.rdatatype.DNSKEY)
if dnskey:
dnskey_ttl = dnskey.ttl
else:
soa = _txn.get(zone.origin, dns.rdatatype.SOA)
dnskey_ttl = soa.ttl
for _, dnskey in keys:
_txn.add(zone.origin, dnskey_ttl, dnskey)
if nsec3:
raise NotImplementedError("Signing with NSEC3 not yet implemented")
else:
_rrset_signer = rrset_signer or functools.partial(
default_rrset_signer,
signer=zone.origin,
ksks=ksks,
zsks=zsks,
inception=inception,
expiration=expiration,
lifetime=lifetime,
policy=policy,
origin=zone.origin,
)
return _sign_zone_nsec(zone, _txn, _rrset_signer)
def _sign_zone_nsec(
zone: dns.zone.Zone,
txn: dns.transaction.Transaction,
rrset_signer: Optional[RRsetSigner] = None,
) -> None:
"""NSEC zone signer"""
def _txn_add_nsec(
txn: dns.transaction.Transaction,
name: dns.name.Name,
next_secure: Optional[dns.name.Name],
rdclass: dns.rdataclass.RdataClass,
ttl: int,
rrset_signer: Optional[RRsetSigner] = None,
) -> None:
"""NSEC zone signer helper"""
mandatory_types = set(
[dns.rdatatype.RdataType.RRSIG, dns.rdatatype.RdataType.NSEC]
)
node = txn.get_node(name)
if node and next_secure:
types = (
set([rdataset.rdtype for rdataset in node.rdatasets]) | mandatory_types
)
windows = Bitmap.from_rdtypes(list(types))
rrset = dns.rrset.from_rdata(
name,
ttl,
NSEC(
rdclass=rdclass,
rdtype=dns.rdatatype.RdataType.NSEC,
next=next_secure,
windows=windows,
),
)
txn.add(rrset)
if rrset_signer:
rrset_signer(txn, rrset)
rrsig_ttl = zone.get_soa().minimum
delegation = None
last_secure = None
for name in sorted(txn.iterate_names()):
if delegation and name.is_subdomain(delegation):
# names below delegations are not secure
continue
elif txn.get(name, dns.rdatatype.NS) and name != zone.origin:
# inside delegation
delegation = name
else:
# outside delegation
delegation = None
if rrset_signer:
node = txn.get_node(name)
if node:
for rdataset in node.rdatasets:
if rdataset.rdtype == dns.rdatatype.RRSIG:
# do not sign RRSIGs
continue
elif delegation and rdataset.rdtype != dns.rdatatype.DS:
# do not sign delegations except DS records
continue
else:
rrset = dns.rrset.from_rdata(name, rdataset.ttl, *rdataset)
rrset_signer(txn, rrset)
# We need "is not None" as the empty name is False because its length is 0.
if last_secure is not None:
_txn_add_nsec(txn, last_secure, name, zone.rdclass, rrsig_ttl, rrset_signer)
last_secure = name
if last_secure:
_txn_add_nsec(
txn, last_secure, zone.origin, zone.rdclass, rrsig_ttl, rrset_signer
)
def _need_pyca(*args, **kwargs):
raise ImportError(
"DNSSEC validation requires python cryptography"
) # pragma: no cover
if dns._features.have("dnssec"):
from cryptography.exceptions import InvalidSignature
from cryptography.hazmat.primitives.asymmetric import dsa # pylint: disable=W0611
from cryptography.hazmat.primitives.asymmetric import ec # pylint: disable=W0611
from cryptography.hazmat.primitives.asymmetric import ed448 # pylint: disable=W0611
from cryptography.hazmat.primitives.asymmetric import rsa # pylint: disable=W0611
from cryptography.hazmat.primitives.asymmetric import ( # pylint: disable=W0611
ed25519,
)
from dns.dnssecalgs import ( # pylint: disable=C0412
get_algorithm_cls,
get_algorithm_cls_from_dnskey,
)
from dns.dnssecalgs.base import GenericPrivateKey, GenericPublicKey
validate = _validate # type: ignore
validate_rrsig = _validate_rrsig # type: ignore
sign = _sign
make_dnskey = _make_dnskey
make_cdnskey = _make_cdnskey
_have_pyca = True
else: # pragma: no cover
validate = _need_pyca
validate_rrsig = _need_pyca
sign = _need_pyca
make_dnskey = _need_pyca
make_cdnskey = _need_pyca
_have_pyca = False
### BEGIN generated Algorithm constants
RSAMD5 = Algorithm.RSAMD5
DH = Algorithm.DH
DSA = Algorithm.DSA
ECC = Algorithm.ECC
RSASHA1 = Algorithm.RSASHA1
DSANSEC3SHA1 = Algorithm.DSANSEC3SHA1
RSASHA1NSEC3SHA1 = Algorithm.RSASHA1NSEC3SHA1
RSASHA256 = Algorithm.RSASHA256
RSASHA512 = Algorithm.RSASHA512
ECCGOST = Algorithm.ECCGOST
ECDSAP256SHA256 = Algorithm.ECDSAP256SHA256
ECDSAP384SHA384 = Algorithm.ECDSAP384SHA384
ED25519 = Algorithm.ED25519
ED448 = Algorithm.ED448
INDIRECT = Algorithm.INDIRECT
PRIVATEDNS = Algorithm.PRIVATEDNS
PRIVATEOID = Algorithm.PRIVATEOID
### END generated Algorithm constants