shoney.arickathil
5f5d774d76
- defensive ASN.1/DER reader: every length/bound checked; malformation is rejection, never over-read (truncated input KAT-gated) - x509_parse: tbsCertificate span, sig-alg OID, signature, SubjectPublicKeyInfo (RSA n/e or EC P-256 x/y), validity dates - wo_x509_verify_one: one chain link's signature, dispatching to phase-D RSA-PKCS1/PSS + ECDSA-P256 by the issuer key type - wo_x509_parse_spki + wo_x509_check_validity (caller supplies time) - KAT against real python-generated chains (test/gen_x509.py): RSA CA+leaf (SHA256withRSA), EC P-256 CA+leaf (ecdsa-with-SHA256); leaf-vs-CA, self-signed CA, wrong-issuer/tampered/truncated reject, validity window, SPKI extraction. test_crypto 84 pass, ASan/UBSan clean - deferred to phase F: SAN/hostname match + multi-cert chain walk to a system CA bundle (both need the target host / trust store, known at handshake time) Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com> (cherry picked from commit 4ec1c75f889df3612e31b9a1a77c4c927fb546c1)
67 lines
2.9 KiB
Python
67 lines
2.9 KiB
Python
#!/usr/bin/env python3
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"""Generate two cert chains (RSA and EC P-256) for the wo_x509 KAT.
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Emits C hex byte arrays: RSA CA + RSA leaf, EC CA + EC leaf."""
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import datetime
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from cryptography import x509
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from cryptography.x509.oid import NameOID
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from cryptography.hazmat.primitives import hashes
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from cryptography.hazmat.primitives.asymmetric import rsa, ec, padding
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from cryptography.hazmat.primitives.serialization import Encoding
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NB = datetime.datetime(2020, 1, 1)
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NA = datetime.datetime(2030, 1, 1)
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def mkname(cn):
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return x509.Name([x509.NameAttribute(NameOID.COMMON_NAME, cn)])
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def selfsigned(key, cn, hashalg, sanhost=None):
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b = (x509.CertificateBuilder()
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.subject_name(mkname(cn)).issuer_name(mkname(cn))
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.public_key(key.public_key())
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.serial_number(x509.random_serial_number())
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.not_valid_before(NB).not_valid_after(NA)
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.add_extension(x509.BasicConstraints(ca=True, path_length=None), True))
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if sanhost:
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b = b.add_extension(x509.SubjectAlternativeName([x509.DNSName(sanhost)]), False)
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return b.sign(key, hashalg)
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def leafcert(leafkey, cakey, ca_cert, cn, hashalg, sanhost):
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return (x509.CertificateBuilder()
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.subject_name(mkname(cn)).issuer_name(ca_cert.subject)
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.public_key(leafkey.public_key())
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.serial_number(x509.random_serial_number())
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.not_valid_before(NB).not_valid_after(NA)
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.add_extension(x509.SubjectAlternativeName([x509.DNSName(sanhost)]), False)
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.sign(cakey, hashalg))
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def cbytes(name, der):
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out = "static const uint8_t %s[] = {" % name
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for i, b in enumerate(der):
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if i % 12 == 0:
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out += "\n "
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out += "0x%02x," % b
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out += "\n};\n"
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return out
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# RSA chain
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rsa_ca_key = rsa.generate_private_key(public_exponent=65537, key_size=2048)
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rsa_ca = selfsigned(rsa_ca_key, "wo-rsa-ca", hashes.SHA256())
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rsa_leaf_key = rsa.generate_private_key(public_exponent=65537, key_size=2048)
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rsa_leaf = leafcert(rsa_leaf_key, rsa_ca_key, rsa_ca, "leaf.example.com",
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hashes.SHA256(), "leaf.example.com")
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# EC chain
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ec_ca_key = ec.generate_private_key(ec.SECP256R1())
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ec_ca = selfsigned(ec_ca_key, "wo-ec-ca", hashes.SHA256())
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ec_leaf_key = ec.generate_private_key(ec.SECP256R1())
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ec_leaf = leafcert(ec_leaf_key, ec_ca_key, ec_ca, "leaf.example.org",
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hashes.SHA256(), "leaf.example.org")
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print("/* Generated by scratchpad/gen_x509.py — python cryptography %s.\n"
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" * Two real chains: RSA CA+leaf (SHA256withRSA), EC P-256 CA+leaf\n"
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" * (ecdsa-with-SHA256). Vectors for the wo_x509 phase-E KAT. */" %
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__import__("cryptography").__version__)
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print(cbytes("kat_rsa_ca", rsa_ca.public_bytes(Encoding.DER)))
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print(cbytes("kat_rsa_leaf", rsa_leaf.public_bytes(Encoding.DER)))
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print(cbytes("kat_ec_ca", ec_ca.public_bytes(Encoding.DER)))
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print(cbytes("kat_ec_leaf", ec_leaf.public_bytes(Encoding.DER)))
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