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[Identity] Include SHA256 thumbprint for CertificateCredential #44990

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[Identity] Include SHA256 thumbprint for CertificateCredential #44990

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16 changes: 12 additions & 4 deletions sdk/identity/azure-identity/azure/identity/_credentials/certificate.py
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Original file line number Diff line number Diff line change
Expand Up @@ -88,14 +88,17 @@ def extract_cert_chain(pem_bytes: bytes) -> bytes:
return b"".join(chain.splitlines())


_Cert = NamedTuple("_Cert", [("pem_bytes", bytes), ("private_key", "Any"), ("fingerprint", bytes)])
_Cert = NamedTuple(
"_Cert", [("pem_bytes", bytes), ("private_key", "Any"), ("fingerprint", bytes), ("sha256_fingerprint", bytes)]
)


def load_pem_certificate(certificate_data: bytes, password: Optional[bytes] = None) -> _Cert:
private_key = serialization.load_pem_private_key(certificate_data, password, backend=default_backend())
cert = x509.load_pem_x509_certificate(certificate_data, default_backend())
fingerprint = cert.fingerprint(hashes.SHA1()) # nosec
return _Cert(certificate_data, private_key, fingerprint)
sha256_fingerprint = cert.fingerprint(hashes.SHA256())
return _Cert(certificate_data, private_key, fingerprint, sha256_fingerprint)


def load_pkcs12_certificate(certificate_data: bytes, password: Optional[bytes] = None) -> _Cert:
Expand All @@ -121,8 +124,9 @@ def load_pkcs12_certificate(certificate_data: bytes, password: Optional[bytes] =
pem_bytes = b"".join(pem_sections)

fingerprint = cert.fingerprint(hashes.SHA1()) # nosec
sha256_fingerprint = cert.fingerprint(hashes.SHA256())

return _Cert(pem_bytes, private_key, fingerprint)
return _Cert(pem_bytes, private_key, fingerprint, sha256_fingerprint)


def get_client_credential(
Expand Down Expand Up @@ -166,7 +170,11 @@ def get_client_credential(
if not isinstance(cert.private_key, RSAPrivateKey):
raise ValueError("The certificate must have an RSA private key because RS256 is used for signing")

client_credential = {"private_key": cert.pem_bytes, "thumbprint": hexlify(cert.fingerprint).decode("utf-8")}
client_credential = {
"private_key": cert.pem_bytes,
"thumbprint": hexlify(cert.fingerprint).decode("utf-8"),
"sha256_thumbprint": hexlify(cert.sha256_fingerprint).decode("utf-8"),
}
if password:
client_credential["passphrase"] = password

Expand Down
23 changes: 22 additions & 1 deletion sdk/identity/azure-identity/tests/test_certificate_credential.py
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Original file line number Diff line number Diff line change
Expand Up @@ -10,7 +10,7 @@
from azure.identity import CertificateCredential, TokenCachePersistenceOptions
from azure.identity._enums import RegionalAuthority
from azure.identity._constants import EnvironmentVariables
from azure.identity._credentials.certificate import load_pkcs12_certificate
from azure.identity._credentials.certificate import get_client_credential, load_pkcs12_certificate
from azure.identity._internal.user_agent import USER_AGENT
from cryptography import x509
from cryptography.hazmat.backends import default_backend
Expand Down Expand Up @@ -50,6 +50,27 @@
EC_CERT_PATH = os.path.join(os.path.dirname(__file__), "ec-certificate.pem")


@pytest.mark.parametrize("cert_path, cert_password", ALL_CERTS)
def test_get_client_credential_includes_sha256_thumbprint(cert_path, cert_password):
client_credential = get_client_credential(certificate_path=cert_path, password=cert_password)

assert "sha256_thumbprint" in client_credential

with open(cert_path, "rb") as f:
cert_bytes = f.read()

if b"-----BEGIN" in cert_bytes:
cert = x509.load_pem_x509_certificate(cert_bytes, default_backend())
else:
from cryptography.hazmat.primitives.serialization import pkcs12

pw = cert_password.encode("utf-8") if isinstance(cert_password, str) else cert_password
_, cert, _ = pkcs12.load_key_and_certificates(cert_bytes, pw, backend=default_backend())

expected_sha256 = cert.fingerprint(hashes.SHA256()).hex()
assert client_credential["sha256_thumbprint"] == expected_sha256


def test_non_rsa_key():
"""The credential should raise ValueError when given a cert without an RSA private key"""
with pytest.raises(ValueError, match=".*RS256.*"):
Expand Down