diff --git a/cryptography/hazmat/backends/openssl/asn1.py b/cryptography/hazmat/backends/openssl/asn1.py
index bf3cf48..6701ea6 100644
--- a/cryptography/hazmat/backends/openssl/asn1.py
+++ b/cryptography/hazmat/backends/openssl/asn1.py
@@ -135,7 +135,7 @@
 long ASN1_INTEGER_get(ASN1_INTEGER *);
 
 BIGNUM *ASN1_INTEGER_to_BN(ASN1_INTEGER *, BIGNUM *);
-ASN1_INTEGER *BN_to_ASN1_INTEGER(const BIGNUM *, ASN1_INTEGER *);
+ASN1_INTEGER *BN_to_ASN1_INTEGER(BIGNUM *, ASN1_INTEGER *);
 """
 
 CUSTOMIZATIONS = """
diff --git a/cryptography/hazmat/backends/openssl/ssl.py b/cryptography/hazmat/backends/openssl/ssl.py
index 499e9c3..fc7ccf3 100644
--- a/cryptography/hazmat/backends/openssl/ssl.py
+++ b/cryptography/hazmat/backends/openssl/ssl.py
@@ -247,7 +247,7 @@
 const SSL_METHOD *SSLv23_client_method(void);
 
 /*- These aren't macros these arguments are all const X on openssl > 1.0.x -*/
-SSL_CTX *SSL_CTX_new(const SSL_METHOD *);
+SSL_CTX *SSL_CTX_new(SSL_METHOD *);
 long SSL_CTX_get_timeout(const SSL_CTX *);
 
 /* SNI APIs were introduced in OpenSSL 1.0.0.  To continue to support
diff --git a/cryptography/hazmat/backends/openssl/x509.py b/cryptography/hazmat/backends/openssl/x509.py
index 2e7505a..840254a 100644
--- a/cryptography/hazmat/backends/openssl/x509.py
+++ b/cryptography/hazmat/backends/openssl/x509.py
@@ -193,8 +193,8 @@
 X509_REVOKED *sk_X509_REVOKED_value(Cryptography_STACK_OF_X509_REVOKED *, int);
 
 /* These aren't macros these arguments are all const X on openssl > 1.0.x */
-int X509_CRL_set_lastUpdate(X509_CRL *, const ASN1_TIME *);
-int X509_CRL_set_nextUpdate(X509_CRL *, const ASN1_TIME *);
+int X509_CRL_set_lastUpdate(X509_CRL *, ASN1_TIME *);
+int X509_CRL_set_nextUpdate(X509_CRL *, ASN1_TIME *);
 """
 
 CUSTOMIZATIONS = """