Ensuring that acme and cryptography respect different key types (#554)

lemur/certificates/service.py

@@ -13,12 +13,12 @@ from flask import current_app
 from cryptography import x509
 from cryptography.hazmat.backends import default_backend
 from cryptography.hazmat.primitives import hashes, serialization
-from cryptography.hazmat.primitives.asymmetric import rsa
 
 from lemur import database
 from lemur.extensions import metrics
 from lemur.plugins.base import plugins
 from lemur.certificates.models import Certificate
+from lemur.common.utils import generate_private_key
 
 from lemur.destinations.models import Destination
 from lemur.notifications.models import Notification
@@ -317,13 +317,7 @@ def create_csr(**csr_config):
     :param csr_config:
     """
 
-    if 'RSA' in csr_config.get('key_type'):
-        key_size = int(csr_config.get('key_type')[3:])
-        private_key = rsa.generate_private_key(
-            public_exponent=65537,
-            key_size=key_size,
-            backend=default_backend()
-        )
+    private_key = generate_private_key(csr_config.get('key_type'))
 
     # TODO When we figure out a better way to validate these options they should be parsed as str
     builder = x509.CertificateSigningRequestBuilder()

lemur/common/utils.py

@@ -11,6 +11,7 @@ import random
 
 from cryptography import x509
 from cryptography.hazmat.backends import default_backend
+from cryptography.hazmat.primitives.asymmetric import rsa
 
 from flask_restful.reqparse import RequestParser
 
@@ -37,12 +38,44 @@ def get_psuedo_random_string():
 
 
 def parse_certificate(body):
+    """
+    Helper function that parses a PEM certificate.
+
+    :param body:
+    :return:
+    """
     if isinstance(body, str):
         body = body.encode('utf-8')
 
     return x509.load_pem_x509_certificate(body, default_backend())
 
 
+def generate_private_key(key_type):
+    """
+    Generates a new private key based on key_type.
+
+    Valid key types: RSA2048, RSA4096
+
+    :param key_type:
+    :return:
+    """
+    valid_key_types = ['RSA2048', 'RSA4096']
+
+    if key_type not in valid_key_types:
+        raise Exception("Invalid key type: {key_type}. Supported key types: {choices}".format(
+            key_type=key_type,
+            choices=",".join(valid_key_types)
+        ))
+
+    if 'RSA' in key_type:
+        key_size = int(key_type[3:])
+        return rsa.generate_private_key(
+            public_exponent=65537,
+            key_size=key_size,
+            backend=default_backend()
+        )
+
+
 def is_weekend(date):
     """
     Determines if a given date is on a weekend.

lemur/plugins/lemur_acme/plugin.py

@@ -16,9 +16,10 @@ from acme.client import Client
 from acme import jose
 from acme import messages
 
+from lemur.common.utils import generate_private_key
+
 from cryptography.hazmat.backends import default_backend
 from cryptography.hazmat.primitives import serialization
-from cryptography.hazmat.primitives.asymmetric import rsa
 
 import OpenSSL.crypto
 
@@ -101,12 +102,6 @@ def request_certificate(acme_client, authorizations, csr):
     return pem_certificate, pem_certificate_chain
 
 
-def generate_rsa_private_key():
-    return rsa.generate_private_key(
-        public_exponent=65537, key_size=2048, backend=default_backend()
-    )
-
-
 def setup_acme_client():
     key = current_app.config.get('ACME_PRIVATE_KEY').strip()
     acme_email = current_app.config.get('ACME_EMAIL')
@@ -127,7 +122,7 @@ def acme_client_for_private_key(acme_directory_url, private_key):
 
 
 def register(email):
-    private_key = generate_rsa_private_key()
+    private_key = generate_private_key('RSA2048')
     acme_client = acme_client_for_private_key(current_app.config('ACME_DIRECTORY_URL'), private_key)
 
     registration = acme_client.register(

lemur/plugins/lemur_cryptography/plugin.py

@@ -13,19 +13,15 @@ from flask import current_app
 from cryptography import x509
 from cryptography.hazmat.backends import default_backend
 from cryptography.hazmat.primitives import hashes, serialization
-from cryptography.hazmat.primitives.asymmetric import rsa
-
 
 from lemur.plugins.bases import IssuerPlugin
 from lemur.plugins import lemur_cryptography as cryptography_issuer
 
+from lemur.common.utils import generate_private_key
+
 
 def build_root_certificate(options):
-    private_key = rsa.generate_private_key(
-        public_exponent=65537,
-        key_size=2048,
-        backend=default_backend()
-    )
+    private_key = generate_private_key(options.get('key_type'))
 
     subject = issuer = x509.Name([
         x509.NameAttribute(x509.OID_COUNTRY_NAME, options['country']),

lemur/plugins/lemur_cryptography/tests/test_cryptography.py

@@ -0,0 +1,36 @@
+import arrow
+
+
+def test_build_root_certificate():
+    from lemur.plugins.lemur_cryptography.plugin import build_root_certificate
+
+    options = {
+        'key_type': 'RSA2048',
+        'country': 'US',
+        'state': 'CA',
+        'location': 'Example place',
+        'organization': 'Example, Inc.',
+        'organizational_unit': 'Example Unit',
+        'common_name': 'Example ROOT',
+        'validity_start': arrow.get('2016-12-01').datetime,
+        'validity_end': arrow.get('2016-12-02').datetime,
+        'first_serial': 1
+
+    }
+    cert_pem, private_key_pem = build_root_certificate(options)
+
+    assert cert_pem
+    assert private_key_pem
+
+
+def test_issue_certificate(authority):
+    from lemur.tests.vectors import CSR_STR
+    from lemur.plugins.lemur_cryptography.plugin import issue_certificate
+
+    options = {
+        'authority': authority,
+        'validity_start': arrow.get('2016-12-01').datetime,
+        'validity_end': arrow.get('2016-12-02').datetime
+    }
+    cert = issue_certificate(CSR_STR, options)
+    assert cert

lemur/tests/test_utils.py

@@ -0,0 +1,11 @@
+import pytest
+
+
+def test_generate_private_key():
+    from lemur.common.utils import generate_private_key
+
+    assert generate_private_key('RSA2048')
+    assert generate_private_key('RSA4096')
+
+    with pytest.raises(Exception):
+        generate_private_key('ECC')

lemur/tests/vectors.py

@@ -269,34 +269,3 @@ zm3Cn4Ul8DO26w9QS4fmZjmnPOZFXYMWoOR6osHzb62PWQ8FBMqXcdToBV2Q9Iw4
 PiFAxlc0tVjlLqQ=
 -----END CERTIFICATE REQUEST-----
 """
-
-
-CSR_PEM_STR = """
------BEGIN RSA PRIVATE KEY-----
-MIIEpgIBAAKCAQEAzZ2PgKflffhIPzwLXe26tuw+7Q72y9dAMrDVEms8u4Cch3yc
-hN6Il5tvM4xTc0UN+aobAhaVoPDN+haXT/XyBRvbFV1f8nvmDQZGdmkyYkZ2xK2X
-MvKnPtjEXdiShPYNKSEqfYQBHhDy08EqBqn+VajmgXoQai+TijVK+yQMVUyB9aFV
-PO8P+sYP1rFIsj6OPVl8Rf9w2TT9VDk2In38SIgEYU2/RLZV6beYjpYnN8P7wV+q
-rB/vlySLrNlhPgAZQFVEEwr3Om4KbuM43PJ5ZtwpapACnMZ9rmxHXq/hYYWoDGBr
-G2BvvyFqymDektAYxNurTTIjpZiHm4poxHRaZwIDAQABAoIBAQCm5MwVBrKtI/ko
-colbbVoPngSZkHrcC9SNEKFyON7r5sGm64t0AdjnDgAd3DnkJ1nnm54efMxo/OyD
-oRCik6QlZ23VkpwNi2m4iq5o8Iw33rAKhkhizzjXN0V0UxTinYEjMEt348ywZdtj
-67c7/4F0cArhb32hYwqjtQwuex0Tofb37Aj5rNPv1n8ytbhz1vriAVZHZEcjdjdn
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-ccg4aqNUtI0zn1snKC58NICxIPP9c0NuHqBuNuwhuRPINfQfjg/aOpE2QycZcew1
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-KMJ/rDKZunQbiacFNOiOhzDzfohOKxV7Z33EqPbUTMRFn4ALFCVcPZA4yWRgx0y1
-vgSd4JQMSzRkyYWFAKd42SuVAoGBAIG84aWQQGdNkin+Y+mhsrCSSE6giDtaE5jz
-y7KHapJe7f/HQnUUIee/zUoSSsbvKcW2CpfCsEdXyFEP9PRidOwAXjO9A7s2fiIW
-9zY7UQO2xLakevtJ6HppxLfOitSFFqr1pJUik9N5TyZw6JCowLqtzeJGGQhI7z60
-vZRIpDS3AoGBAPYJgNB7EcWj5U39ol+8cofG1kPauoEaildTur5ftzyzjy4DXrOW
-sfU/xhUp6EKLGSXEPqeXAWR6ARf1F4U9Ozp6KA93lGSrSY561jKoqhxxOXAf5il2
-p7Fzh2CckUeiGd5el+h2WUCOcgtlPlfRyV/Mlvx1H0gFieGucXTP23Ox
------END RSA PRIVATE KEY-----
-"""

setup.cfg

@@ -1,4 +1,4 @@
-[pytest]
+[tool:pytest]
 python_files=test*.py
 addopts=--tb=native -p no:doctest
 norecursedirs=bin dist docs	htmlcov script hooks node_modules .* {args}