OCSP request parsing (#4393)

* add public_bytes to OCSPRequest

* review feedback

* OCSP request parsing

* change some prose

* add __len__ as a required method

1 files changed, 11 insertions, 0 deletions

diff --git a/src/cryptography/hazmat/backends/openssl/backend.py b/src/cryptography/hazmat/backends/openssl/backend.py
index af14bfaa..6a0446bc 100644
--- a/src/cryptography/hazmat/backends/openssl/backend.py
+++ b/src/cryptography/hazmat/backends/openssl/backend.py
@@ -40,6 +40,7 @@ from cryptography.hazmat.backends.openssl.encode_asn1 import (
 )
 from cryptography.hazmat.backends.openssl.hashes import _HashContext
 from cryptography.hazmat.backends.openssl.hmac import _HMACContext
+from cryptography.hazmat.backends.openssl.ocsp import _OCSPRequest
 from cryptography.hazmat.backends.openssl.rsa import (
     _RSAPrivateKey, _RSAPublicKey
 )
@@ -1419,6 +1420,16 @@ class Backend(object):
 
         return _EllipticCurvePrivateKey(self, ec_cdata, evp_pkey)
 
+    def load_der_ocsp_request(self, data):
+        mem_bio = self._bytes_to_bio(data)
+        request = self._lib.d2i_OCSP_REQUEST_bio(mem_bio.bio, self._ffi.NULL)
+        if request == self._ffi.NULL:
+            self._consume_errors()
+            raise ValueError("Unable to load OCSP request")
+
+        request = self._ffi.gc(request, self._lib.OCSP_REQUEST_free)
+        return _OCSPRequest(self, request)
+
     def elliptic_curve_exchange_algorithm_supported(self, algorithm, curve):
         return (
             self.elliptic_curve_supported(curve) and