in functions/source/populate_NLB_TG_with_ALB/dns/dnssec.py [0:0]
def _validate_rrsig(rrset, rrsig, keys, origin=None, now=None):
"""Validate an RRset against a single signature rdata
The owner name of the rrsig is assumed to be the same as the owner name
of the rrset.
@param rrset: The RRset to validate
@type rrset: dns.rrset.RRset or (dns.name.Name, dns.rdataset.Rdataset)
tuple
@param rrsig: The signature rdata
@type rrsig: dns.rrset.Rdata
@param keys: The key dictionary.
@type keys: a dictionary keyed by dns.name.Name with node or rdataset
values
@param origin: The origin to use for relative names
@type origin: dns.name.Name or None
@param now: The time to use when validating the signatures. The default
is the current time.
@type now: int
"""
if isinstance(origin, string_types):
origin = dns.name.from_text(origin, dns.name.root)
for candidate_key in _find_candidate_keys(keys, rrsig):
if not candidate_key:
raise ValidationFailure('unknown key')
# For convenience, allow the rrset to be specified as a (name,
# rdataset) tuple as well as a proper rrset
if isinstance(rrset, tuple):
rrname = rrset[0]
rdataset = rrset[1]
else:
rrname = rrset.name
rdataset = rrset
if now is None:
now = time.time()
if rrsig.expiration < now:
raise ValidationFailure('expired')
if rrsig.inception > now:
raise ValidationFailure('not yet valid')
hash = _make_hash(rrsig.algorithm)
if _is_rsa(rrsig.algorithm):
keyptr = candidate_key.key
(bytes_,) = struct.unpack('!B', keyptr[0:1])
keyptr = keyptr[1:]
if bytes_ == 0:
(bytes_,) = struct.unpack('!H', keyptr[0:2])
keyptr = keyptr[2:]
rsa_e = keyptr[0:bytes_]
rsa_n = keyptr[bytes_:]
keylen = len(rsa_n) * 8
pubkey = Crypto.PublicKey.RSA.construct(
(Crypto.Util.number.bytes_to_long(rsa_n),
Crypto.Util.number.bytes_to_long(rsa_e)))
sig = (Crypto.Util.number.bytes_to_long(rrsig.signature),)
elif _is_dsa(rrsig.algorithm):
keyptr = candidate_key.key
(t,) = struct.unpack('!B', keyptr[0:1])
keyptr = keyptr[1:]
octets = 64 + t * 8
dsa_q = keyptr[0:20]
keyptr = keyptr[20:]
dsa_p = keyptr[0:octets]
keyptr = keyptr[octets:]
dsa_g = keyptr[0:octets]
keyptr = keyptr[octets:]
dsa_y = keyptr[0:octets]
pubkey = Crypto.PublicKey.DSA.construct(
(Crypto.Util.number.bytes_to_long(dsa_y),
Crypto.Util.number.bytes_to_long(dsa_g),
Crypto.Util.number.bytes_to_long(dsa_p),
Crypto.Util.number.bytes_to_long(dsa_q)))
(dsa_r, dsa_s) = struct.unpack('!20s20s', rrsig.signature[1:])
sig = (Crypto.Util.number.bytes_to_long(dsa_r),
Crypto.Util.number.bytes_to_long(dsa_s))
elif _is_ecdsa(rrsig.algorithm):
if rrsig.algorithm == ECDSAP256SHA256:
curve = ecdsa.curves.NIST256p
key_len = 32
elif rrsig.algorithm == ECDSAP384SHA384:
curve = ecdsa.curves.NIST384p
key_len = 48
else:
# shouldn't happen
raise ValidationFailure('unknown ECDSA curve')
keyptr = candidate_key.key
x = Crypto.Util.number.bytes_to_long(keyptr[0:key_len])
y = Crypto.Util.number.bytes_to_long(keyptr[key_len:key_len * 2])
assert ecdsa.ecdsa.point_is_valid(curve.generator, x, y)
point = ecdsa.ellipticcurve.Point(curve.curve, x, y, curve.order)
verifying_key = ecdsa.keys.VerifyingKey.from_public_point(point,
curve)
pubkey = ECKeyWrapper(verifying_key, key_len)
r = rrsig.signature[:key_len]
s = rrsig.signature[key_len:]
sig = ecdsa.ecdsa.Signature(Crypto.Util.number.bytes_to_long(r),
Crypto.Util.number.bytes_to_long(s))
else:
raise ValidationFailure('unknown algorithm %u' % rrsig.algorithm)
hash.update(_to_rdata(rrsig, origin)[:18])
hash.update(rrsig.signer.to_digestable(origin))
if rrsig.labels < len(rrname) - 1:
suffix = rrname.split(rrsig.labels + 1)[1]
rrname = dns.name.from_text('*', suffix)
rrnamebuf = rrname.to_digestable(origin)
rrfixed = struct.pack('!HHI', rdataset.rdtype, rdataset.rdclass,
rrsig.original_ttl)
rrlist = sorted(rdataset)
for rr in rrlist:
hash.update(rrnamebuf)
hash.update(rrfixed)
rrdata = rr.to_digestable(origin)
rrlen = struct.pack('!H', len(rrdata))
hash.update(rrlen)
hash.update(rrdata)
digest = hash.digest()
if _is_rsa(rrsig.algorithm):
# PKCS1 algorithm identifier goop
digest = _make_algorithm_id(rrsig.algorithm) + digest
padlen = keylen // 8 - len(digest) - 3
digest = struct.pack('!%dB' % (2 + padlen + 1),
*([0, 1] + [0xFF] * padlen + [0])) + digest
elif _is_dsa(rrsig.algorithm) or _is_ecdsa(rrsig.algorithm):
pass
else:
# Raise here for code clarity; this won't actually ever happen
# since if the algorithm is really unknown we'd already have
# raised an exception above
raise ValidationFailure('unknown algorithm %u' % rrsig.algorithm)
if pubkey.verify(digest, sig):
return
raise ValidationFailure('verify failure')