Make default_method mostly compile-time

Document thread-safety issues
Have RSA_null return NULL (always fails)

Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2244)

1 files changed, 12 insertions, 0 deletions

diff --git a/crypto/dh/dh_key.c b/crypto/dh/dh_key.c
index 204e5a7..fce9ff4 100644
--- a/crypto/dh/dh_key.c
+++ b/crypto/dh/dh_key.c
@@ -56,11 +56,23 @@ static DH_METHOD dh_ossl = {
     NULL
 };
 
+static const DH_METHOD *default_DH_method = &dh_ossl;
+
 const DH_METHOD *DH_OpenSSL(void)
 {
     return &dh_ossl;
 }
 
+void DH_set_default_method(const DH_METHOD *meth)
+{
+    default_DH_method = meth;
+}
+
+const DH_METHOD *DH_get_default_method(void)
+{
+    return default_DH_method;
+}
+
 static int generate_key(DH *dh)
 {
     int ok = 0;