Bump dnspython from 2.3.0 to 2.4.2 (#2123)

* Bump dnspython from 2.3.0 to 2.4.2

Bumps [dnspython](https://github.com/rthalley/dnspython) from 2.3.0 to 2.4.2.
- [Release notes](https://github.com/rthalley/dnspython/releases)
- [Changelog](https://github.com/rthalley/dnspython/blob/master/doc/whatsnew.rst)
- [Commits](https://github.com/rthalley/dnspython/compare/v2.3.0...v2.4.2)

---
updated-dependencies:
- dependency-name: dnspython
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

* Update dnspython==2.4.2

---------

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: JonnyWong16 <9099342+JonnyWong16@users.noreply.github.com>

[skip ci]

lib/dns/dnssecalgs/ecdsa.py

@@ -0,0 +1,89 @@
+from cryptography.hazmat.backends import default_backend
+from cryptography.hazmat.primitives import hashes
+from cryptography.hazmat.primitives.asymmetric import ec, utils
+
+from dns.dnssecalgs.cryptography import CryptographyPrivateKey, CryptographyPublicKey
+from dns.dnssectypes import Algorithm
+from dns.rdtypes.ANY.DNSKEY import DNSKEY
+
+
+class PublicECDSA(CryptographyPublicKey):
+    key: ec.EllipticCurvePublicKey
+    key_cls = ec.EllipticCurvePublicKey
+    algorithm: Algorithm
+    chosen_hash: hashes.HashAlgorithm
+    curve: ec.EllipticCurve
+    octets: int
+
+    def verify(self, signature: bytes, data: bytes) -> None:
+        sig_r = signature[0 : self.octets]
+        sig_s = signature[self.octets :]
+        sig = utils.encode_dss_signature(
+            int.from_bytes(sig_r, "big"), int.from_bytes(sig_s, "big")
+        )
+        self.key.verify(sig, data, ec.ECDSA(self.chosen_hash))
+
+    def encode_key_bytes(self) -> bytes:
+        """Encode a public key per RFC 6605, section 4."""
+        pn = self.key.public_numbers()
+        return pn.x.to_bytes(self.octets, "big") + pn.y.to_bytes(self.octets, "big")
+
+    @classmethod
+    def from_dnskey(cls, key: DNSKEY) -> "PublicECDSA":
+        cls._ensure_algorithm_key_combination(key)
+        ecdsa_x = key.key[0 : cls.octets]
+        ecdsa_y = key.key[cls.octets : cls.octets * 2]
+        return cls(
+            key=ec.EllipticCurvePublicNumbers(
+                curve=cls.curve,
+                x=int.from_bytes(ecdsa_x, "big"),
+                y=int.from_bytes(ecdsa_y, "big"),
+            ).public_key(default_backend()),
+        )
+
+
+class PrivateECDSA(CryptographyPrivateKey):
+    key: ec.EllipticCurvePrivateKey
+    key_cls = ec.EllipticCurvePrivateKey
+    public_cls = PublicECDSA
+
+    def sign(self, data: bytes, verify: bool = False) -> bytes:
+        """Sign using a private key per RFC 6605, section 4."""
+        der_signature = self.key.sign(data, ec.ECDSA(self.public_cls.chosen_hash))
+        dsa_r, dsa_s = utils.decode_dss_signature(der_signature)
+        signature = int.to_bytes(
+            dsa_r, length=self.public_cls.octets, byteorder="big"
+        ) + int.to_bytes(dsa_s, length=self.public_cls.octets, byteorder="big")
+        if verify:
+            self.public_key().verify(signature, data)
+        return signature
+
+    @classmethod
+    def generate(cls) -> "PrivateECDSA":
+        return cls(
+            key=ec.generate_private_key(
+                curve=cls.public_cls.curve, backend=default_backend()
+            ),
+        )
+
+
+class PublicECDSAP256SHA256(PublicECDSA):
+    algorithm = Algorithm.ECDSAP256SHA256
+    chosen_hash = hashes.SHA256()
+    curve = ec.SECP256R1()
+    octets = 32
+
+
+class PrivateECDSAP256SHA256(PrivateECDSA):
+    public_cls = PublicECDSAP256SHA256
+
+
+class PublicECDSAP384SHA384(PublicECDSA):
+    algorithm = Algorithm.ECDSAP384SHA384
+    chosen_hash = hashes.SHA384()
+    curve = ec.SECP384R1()
+    octets = 48
+
+
+class PrivateECDSAP384SHA384(PrivateECDSA):
+    public_cls = PublicECDSAP384SHA384