Merge pull request #2815 from reaperhulk/error-on-unusual-encodings

Error on unusual encodings

2 files changed, 26 insertions, 1 deletions

diff --git a/src/cryptography/hazmat/backends/openssl/decode_asn1.py b/src/cryptography/hazmat/backends/openssl/decode_asn1.py
index 140d3de4..26f56d12 100644
--- a/src/cryptography/hazmat/backends/openssl/decode_asn1.py
+++ b/src/cryptography/hazmat/backends/openssl/decode_asn1.py
@@ -709,7 +709,11 @@ def _asn1_string_to_ascii(backend, asn1_string):
 def _asn1_string_to_utf8(backend, asn1_string):
     buf = backend._ffi.new("unsigned char **")
     res = backend._lib.ASN1_STRING_to_UTF8(buf, asn1_string)
-    backend.openssl_assert(res >= 0)
+    if res == -1:
+        raise ValueError(
+            "Unsupported ASN1 string type. Type: {0}".format(asn1_string.type)
+        )
+
     backend.openssl_assert(buf[0] != backend._ffi.NULL)
     buf = backend._ffi.gc(
         buf, lambda buffer: backend._lib.OPENSSL_free(buffer[0])
diff --git a/tests/hazmat/backends/test_openssl.py b/tests/hazmat/backends/test_openssl.py
index 072f8be3..52bee7b3 100644
--- a/tests/hazmat/backends/test_openssl.py
+++ b/tests/hazmat/backends/test_openssl.py
@@ -31,6 +31,7 @@ from ..primitives.test_ec import _skip_curve_unsupported
 from ...doubles import (
     DummyAsymmetricPadding, DummyCipherAlgorithm, DummyHashAlgorithm, DummyMode
 )
+from ...test_x509 import _load_cert
 from ...utils import load_vectors_from_file, raises_unsupported_algorithm
 
 
@@ -656,3 +657,23 @@ class TestRSAPEMSerialization(object):
                 serialization.PrivateFormat.PKCS8,
                 serialization.BestAvailableEncryption(password)
             )
+
+
+class TestGOSTCertificate(object):
+    @pytest.mark.skipif(
+        backend._lib.OPENSSL_VERSION_NUMBER < 0x1000000f,
+        reason="Requires a newer OpenSSL. Must be >= 1.0.0"
+    )
+    def test_numeric_string_x509_name_entry(self):
+        cert = _load_cert(
+            os.path.join("x509", "e-trust.ru.der"),
+            x509.load_der_x509_certificate,
+            backend
+        )
+        with pytest.raises(ValueError) as exc:
+            cert.subject
+
+        # We assert on the message in this case because if the certificate
+        # fails to load it will also raise a ValueError and this test could
+        # erroneously pass.
+        assert str(exc.value) == "Unsupported ASN1 string type. Type: 18"