Accept NULL in *_free.
diff --git a/ssl/ssl_cert.c b/ssl/ssl_cert.c
index 1bff91e..7d4531d 100644
--- a/ssl/ssl_cert.c
+++ b/ssl/ssl_cert.c
@@ -105,6 +105,9 @@
 	{
 	int i;
 
+	if(c == NULL)
+	    return;
+
 	i=CRYPTO_add(&c->references,-1,CRYPTO_LOCK_SSL_CERT);
 #ifdef REF_PRINT
 	REF_PRINT("CERT",c);