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KMS: fix RSA PSS signing issue for salt length #12467

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Merged
merged 1 commit into from
Apr 4, 2025
Merged

KMS: fix RSA PSS signing issue for salt length #12467

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2 changes: 1 addition & 1 deletion localstack-core/localstack/services/kms/models.py
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Original file line number Diff line number Diff line change
Expand Up @@ -476,7 +476,7 @@ def _construct_sign_verify_padding(
if "PKCS" in signing_algorithm:
return padding.PKCS1v15()
elif "PSS" in signing_algorithm:
return padding.PSS(mgf=padding.MGF1(hasher), salt_length=padding.PSS.MAX_LENGTH)
return padding.PSS(mgf=padding.MGF1(hasher), salt_length=padding.PSS.DIGEST_LENGTH)
else:
LOG.warning("Unsupported padding in SigningAlgorithm '%s'", signing_algorithm)

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57 changes: 56 additions & 1 deletion tests/aws/services/kms/test_kms.py
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Original file line number Diff line number Diff line change
Expand Up @@ -10,7 +10,7 @@
from botocore.config import Config
from botocore.exceptions import ClientError
from cryptography.hazmat.primitives import hashes, hmac, serialization
from cryptography.hazmat.primitives.asymmetric import ec, padding
from cryptography.hazmat.primitives.asymmetric import ec, padding, utils
from cryptography.hazmat.primitives.serialization import load_der_public_key

from localstack.services.kms.models import IV_LEN, Ciphertext, _serialize_ciphertext_blob
Expand All @@ -26,6 +26,27 @@ def create_tags(**kwargs):
return [{"TagKey": key, "TagValue": value} for key, value in kwargs.items()]


def get_signature_kwargs(signing_algorithm, message_type):
algo_map = {
"SHA_256": (hashes.SHA256(), 32),
"SHA_384": (hashes.SHA384(), 48),
"SHA_512": (hashes.SHA512(), 64),
}
hasher, salt = next((h, s) for k, (h, s) in algo_map.items() if k in signing_algorithm)
algorithm = utils.Prehashed(hasher) if message_type == "DIGEST" else hasher
kwargs = {}

if signing_algorithm.startswith("ECDSA"):
kwargs["signature_algorithm"] = ec.ECDSA(algorithm)
elif signing_algorithm.startswith("RSA"):
if "PKCS" in signing_algorithm:
kwargs["padding"] = padding.PKCS1v15()
elif "PSS" in signing_algorithm:
kwargs["padding"] = padding.PSS(mgf=padding.MGF1(hasher), salt_length=salt)
kwargs["algorithm"] = algorithm
return kwargs


@pytest.fixture(scope="class")
def kms_client_for_region(aws_client_factory):
def _kms_client(
Expand Down Expand Up @@ -724,6 +745,40 @@ def test_sign_verify(self, kms_create_key, snapshot, key_spec, sign_algo, aws_cl
)
assert exc.match("ValidationException")

@markers.aws.validated
@pytest.mark.parametrize(
"key_spec,sign_algo",
[
("RSA_2048", "RSASSA_PSS_SHA_256"),
("RSA_2048", "RSASSA_PSS_SHA_384"),
("RSA_2048", "RSASSA_PSS_SHA_512"),
("RSA_4096", "RSASSA_PKCS1_V1_5_SHA_256"),
("RSA_4096", "RSASSA_PKCS1_V1_5_SHA_512"),
("ECC_NIST_P256", "ECDSA_SHA_256"),
("ECC_NIST_P384", "ECDSA_SHA_384"),
("ECC_SECG_P256K1", "ECDSA_SHA_256"),
],
Comment on lines +749 to +760
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@k-a-il k-a-il Apr 3, 2025 •
edited
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nice parametrized test :)

)
def test_verify_salt_length(self, aws_client, kms_create_key, key_spec, sign_algo):
plaintext = b"test message !%$@ 1234567890"

hash_algo = get_hash_algorithm(sign_algo)
hasher = getattr(hashlib, hash_algo.replace("_", "").lower())
digest = hasher(plaintext).digest()

key_id = kms_create_key(KeyUsage="SIGN_VERIFY", KeySpec=key_spec)["KeyId"]
public_key = aws_client.kms.get_public_key(KeyId=key_id)["PublicKey"]
key = load_der_public_key(public_key)

kwargs = {"KeyId": key_id, "SigningAlgorithm": sign_algo}

for msg_type, message in [("RAW", plaintext), ("DIGEST", digest)]:
signature = aws_client.kms.sign(MessageType=msg_type, Message=message, **kwargs)[
"Signature"
]
vargs = get_signature_kwargs(sign_algo, msg_type)
key.verify(signature=signature, data=message, **vargs)

@markers.aws.validated
def test_invalid_key_usage(self, kms_create_key, aws_client):
key_id = kms_create_key(KeyUsage="ENCRYPT_DECRYPT", KeySpec="RSA_4096")["KeyId"]
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32 changes: 32 additions & 0 deletions tests/aws/services/kms/test_kms.snapshot.json
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Original file line number Diff line number Diff line change
Expand Up @@ -2152,5 +2152,37 @@
}
}
}
},
"tests/aws/services/kms/test_kms.py::TestKMS::test_verify_salt_length[RSA_2048-RSASSA_PSS_SHA_256]": {
"recorded-date": "02-04-2025, 06:06:52",
"recorded-content": {}
},
"tests/aws/services/kms/test_kms.py::TestKMS::test_verify_salt_length[RSA_2048-RSASSA_PSS_SHA_384]": {
"recorded-date": "02-04-2025, 06:06:54",
"recorded-content": {}
},
"tests/aws/services/kms/test_kms.py::TestKMS::test_verify_salt_length[RSA_2048-RSASSA_PSS_SHA_512]": {
"recorded-date": "02-04-2025, 06:06:57",
"recorded-content": {}
},
"tests/aws/services/kms/test_kms.py::TestKMS::test_verify_salt_length[RSA_4096-RSASSA_PKCS1_V1_5_SHA_256]": {
"recorded-date": "02-04-2025, 06:06:59",
"recorded-content": {}
},
"tests/aws/services/kms/test_kms.py::TestKMS::test_verify_salt_length[RSA_4096-RSASSA_PKCS1_V1_5_SHA_512]": {
"recorded-date": "02-04-2025, 06:07:01",
"recorded-content": {}
},
"tests/aws/services/kms/test_kms.py::TestKMS::test_verify_salt_length[ECC_NIST_P256-ECDSA_SHA_256]": {
"recorded-date": "02-04-2025, 06:07:03",
"recorded-content": {}
},
"tests/aws/services/kms/test_kms.py::TestKMS::test_verify_salt_length[ECC_NIST_P384-ECDSA_SHA_384]": {
"recorded-date": "02-04-2025, 06:07:06",
"recorded-content": {}
},
"tests/aws/services/kms/test_kms.py::TestKMS::test_verify_salt_length[ECC_SECG_P256K1-ECDSA_SHA_256]": {
"recorded-date": "02-04-2025, 06:07:08",
"recorded-content": {}
}
}
24 changes: 24 additions & 0 deletions tests/aws/services/kms/test_kms.validation.json
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Original file line number Diff line number Diff line change
Expand Up @@ -275,6 +275,30 @@
"tests/aws/services/kms/test_kms.py::TestKMS::test_update_key_description": {
"last_validated_date": "2024-04-11T15:53:46+00:00"
},
"tests/aws/services/kms/test_kms.py::TestKMS::test_verify_salt_length[ECC_NIST_P256-ECDSA_SHA_256]": {
"last_validated_date": "2025-04-02T06:07:03+00:00"
},
"tests/aws/services/kms/test_kms.py::TestKMS::test_verify_salt_length[ECC_NIST_P384-ECDSA_SHA_384]": {
"last_validated_date": "2025-04-02T06:07:05+00:00"
},
"tests/aws/services/kms/test_kms.py::TestKMS::test_verify_salt_length[ECC_SECG_P256K1-ECDSA_SHA_256]": {
"last_validated_date": "2025-04-02T06:07:08+00:00"
},
"tests/aws/services/kms/test_kms.py::TestKMS::test_verify_salt_length[RSA_2048-RSASSA_PSS_SHA_256]": {
"last_validated_date": "2025-04-02T06:06:52+00:00"
},
"tests/aws/services/kms/test_kms.py::TestKMS::test_verify_salt_length[RSA_2048-RSASSA_PSS_SHA_384]": {
"last_validated_date": "2025-04-02T06:06:54+00:00"
},
"tests/aws/services/kms/test_kms.py::TestKMS::test_verify_salt_length[RSA_2048-RSASSA_PSS_SHA_512]": {
"last_validated_date": "2025-04-02T06:06:56+00:00"
},
"tests/aws/services/kms/test_kms.py::TestKMS::test_verify_salt_length[RSA_4096-RSASSA_PKCS1_V1_5_SHA_256]": {
"last_validated_date": "2025-04-02T06:06:58+00:00"
},
"tests/aws/services/kms/test_kms.py::TestKMS::test_verify_salt_length[RSA_4096-RSASSA_PKCS1_V1_5_SHA_512]": {
"last_validated_date": "2025-04-02T06:07:01+00:00"
},
"tests/aws/services/kms/test_kms.py::TestKMSGenerateKeys::test_encryption_context_generate_data_key": {
"last_validated_date": "2024-04-11T15:54:32+00:00"
},
Expand Down
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