allow parsing of nonstandard country name and jurisdiction country name (#6641)

The spec requires both of these to be exactly two characters to
correspond with ISO country codes. Reality is sometimes messier, so this
allows parsing (but not encoding) of this invalid data. Parsing will
raise a UserWarning if incorrect lengths are detected.

Author: reaperhulk

docs/development/test-vectors.rst

@@ -444,6 +444,9 @@ Custom X.509 Vectors
   version.
 * ``invalid-sct-length.der`` - A certificate with an SCT with an internal
   length greater than the amount of data.
+* ``bad_country.pem`` - A certificate with country name and jurisdiction
+  country name values in its subject and issuer distinguished names which
+  are longer than 2 characters.
 
 Custom X.509 Request Vectors
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~

src/cryptography/x509/name.py

@@ -3,6 +3,7 @@
 # for complete details.
 
 import typing
+import warnings
 
 from cryptography import utils
 from cryptography.hazmat.bindings._rust import (
@@ -79,7 +80,12 @@ def _escape_dn_value(val: str) -> str:
 
 class NameAttribute(object):
     def __init__(
-        self, oid: ObjectIdentifier, value: str, _type=_SENTINEL
+        self,
+        oid: ObjectIdentifier,
+        value: str,
+        _type=_SENTINEL,
+        *,
+        _validate=True,
     ) -> None:
         if not isinstance(oid, ObjectIdentifier):
             raise TypeError(
@@ -93,10 +99,17 @@ def __init__(
             oid == NameOID.COUNTRY_NAME
             or oid == NameOID.JURISDICTION_COUNTRY_NAME
         ):
-            if len(value.encode("utf8")) != 2:
+            c_len = len(value.encode("utf8"))
+            if c_len != 2 and _validate is True:
                 raise ValueError(
                     "Country name must be a 2 character country code"
                 )
+            elif c_len != 2:
+                warnings.warn(
+                    "Country names should be two characters, but the "
+                    "attribute is {} characters in length.".format(c_len),
+                    stacklevel=2,
+                )
 
         # The appropriate ASN1 string type varies by OID and is defined across
         # multiple RFCs including 2459, 3280, and 5280. In general UTF8String

src/rust/src/x509/common.rs

@@ -5,6 +5,7 @@
 use crate::asn1::PyAsn1Error;
 use crate::x509;
 use chrono::{Datelike, TimeZone, Timelike};
+use pyo3::types::IntoPyDict;
 use pyo3::ToPyObject;
 use std::collections::HashSet;
 use std::convert::TryInto;
@@ -382,8 +383,9 @@ fn parse_name_attribute(
         _ => std::str::from_utf8(attribute.value.data())
             .map_err(|_| asn1::ParseError::new(asn1::ParseErrorKind::InvalidValue))?,
     };
+    let kwargs = [("_validate", false)].into_py_dict(py);
     Ok(x509_module
-        .call_method1("NameAttribute", (oid, py_data, py_tag))?
+        .call_method("NameAttribute", (oid, py_data, py_tag), Some(kwargs))?
         .to_object(py))
 }
 

tests/x509/test_x509.py

@@ -747,6 +747,28 @@ def test_negative_serial_number(self, backend):
         with pytest.warns(utils.DeprecatedIn36):
             assert cert.serial_number == -18008675309
 
+    def test_country_jurisdiction_country_too_long(self, backend):
+        cert = _load_cert(
+            os.path.join("x509", "custom", "bad_country.pem"),
+            x509.load_pem_x509_certificate,
+            backend,
+        )
+        with pytest.warns(UserWarning):
+            assert (
+                cert.subject.get_attributes_for_oid(x509.NameOID.COUNTRY_NAME)[
+                    0
+                ].value
+                == "too long"
+            )
+
+        with pytest.warns(UserWarning):
+            assert (
+                cert.subject.get_attributes_for_oid(
+                    x509.NameOID.JURISDICTION_COUNTRY_NAME
+                )[0].value
+                == "also too long"
+            )
+
     def test_alternate_rsa_with_sha1_oid(self, backend):
         cert = _load_cert(
             os.path.join("x509", "custom", "alternate-rsa-sha1-oid.der"),

vectors/cryptography_vectors/x509/custom/bad_country.pem

@@ -0,0 +1,18 @@
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----