fixes #4706 -- don't internal error on corrupt private key (#5307)

* fixes #4706 -- don't internal error on corrupt private key

* Temporary disable paramiko

.travis.yml

@@ -118,8 +118,10 @@ matrix:
           env: DOWNSTREAM=pyopenssl
         - python: 3.7
           env: DOWNSTREAM=twisted OPENSSL=1.1.1g
-        - python: 2.7
-          env: DOWNSTREAM=paramiko
+        # Temporary disabled until
+        # https://github.com/paramiko/paramiko/pull/1723 is merged
+        # - python: 2.7
+        #   env: DOWNSTREAM=paramiko
         - python: 2.7
           env: DOWNSTREAM=aws-encryption-sdk
         - python: 2.7

src/cryptography/hazmat/backends/openssl/rsa.py

@@ -314,6 +314,11 @@ class _RSAVerificationContext(object):
 @utils.register_interface(RSAPrivateKeyWithSerialization)
 class _RSAPrivateKey(object):
     def __init__(self, backend, rsa_cdata, evp_pkey):
+        res = backend._lib.RSA_check_key(rsa_cdata)
+        if res != 1:
+            errors = backend._consume_errors_with_text()
+            raise ValueError("Invalid private key", errors)
+
         self._backend = backend
         self._rsa_cdata = rsa_cdata
         self._evp_pkey = evp_pkey

tests/hazmat/primitives/fixtures_rsa.py

@@ -784,3 +784,33 @@ RSA_KEY_2048_ALT = RSAPrivateNumbers(
         ),
     ),
 )
+
+RSA_KEY_CORRUPTED = b"""
+-----BEGIN RSA PRIVATE KEY-----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+-----END RSA PRIVATE KEY-----
+"""

tests/hazmat/primitives/test_rsa.py

@@ -49,6 +49,7 @@ from .fixtures_rsa import (
     RSA_KEY_599,
     RSA_KEY_745,
     RSA_KEY_768,
+    RSA_KEY_CORRUPTED,
 )
 from .utils import (
     _check_rsa_private_numbers,
@@ -729,6 +730,12 @@ class TestRSASignature(object):
                 asym_utils.Prehashed(hashes.SHA1()),
             )
 
+    def test_corrupted_private_key(self, backend):
+        with pytest.raises(ValueError):
+            serialization.load_pem_private_key(
+                RSA_KEY_CORRUPTED, password=None, backend=backend
+            )
+
 
 @pytest.mark.requires_backend_interface(interface=RSABackend)
 class TestRSAVerification(object):