EVP_PKEY_asn1_{new,copy}(): pointless zeroing + a tiny bug

[Theo Buehler]

Very minor polishing, really:

Since we converted EVP_PKEY_asn1_new() to using calloc(), there's no
need to set the structure to zero manually with an odd spelling of NULL.
Besides, the list of zeroed members is incomplete: it misses sig_print.

Copy-pasting this list is likely the reason why EVP_PKEY_asn1_copy()
forgets to copy that member. Luckily, this copy function is rarely used
and the omitted callback is only used once (in X509_signature_print()).

Index: lib/libcrypto/asn1/ameth_lib.c
===================================================================
RCS file: /var/cvs/src/lib/libcrypto/asn1/ameth_lib.c,v
retrieving revision 1.17
diff -u -p -r1.17 ameth_lib.c
--- lib/libcrypto/asn1/ameth_lib.c      13 May 2018 06:40:55 -0000      1.17
+++ lib/libcrypto/asn1/ameth_lib.c      23 May 2018 06:42:11 -0000
@@ -309,59 +309,26 @@ EVP_PKEY_asn1_new(int id, int flags, con
 {
        EVP_PKEY_ASN1_METHOD *ameth;
 
-       ameth = calloc(1, sizeof(EVP_PKEY_ASN1_METHOD));
-       if (!ameth)
+       if ((ameth = calloc(1, sizeof(EVP_PKEY_ASN1_METHOD))) == NULL)
                return NULL;
 
        ameth->pkey_id = id;
        ameth->pkey_base_id = id;
        ameth->pkey_flags = flags | ASN1_PKEY_DYNAMIC;
 
-       if (info) {
-               ameth->info = strdup(info);
-               if (!ameth->info)
+       if (info != NULL) {
+               if ((ameth->info = strdup(info)) == NULL)
                        goto err;
-       } else
-               ameth->info = NULL;
+       }
 
-       if (pem_str) {
-               ameth->pem_str = strdup(pem_str);
-               if (!ameth->pem_str)
+       if (pem_str != NULL) {
+               if ((ameth->pem_str = strdup(pem_str)) == NULL)
                        goto err;
-       } else
-               ameth->pem_str = NULL;
-
-       ameth->pub_decode = 0;
-       ameth->pub_encode = 0;
-       ameth->pub_cmp = 0;
-       ameth->pub_print = 0;
-
-       ameth->priv_decode = 0;
-       ameth->priv_encode = 0;
-       ameth->priv_print = 0;
-
-       ameth->old_priv_encode = 0;
-       ameth->old_priv_decode = 0;
-
-       ameth->item_verify = 0;
-       ameth->item_sign = 0;
-
-       ameth->pkey_size = 0;
-       ameth->pkey_bits = 0;
-
-       ameth->param_decode = 0;
-       ameth->param_encode = 0;
-       ameth->param_missing = 0;
-       ameth->param_copy = 0;
-       ameth->param_cmp = 0;
-       ameth->param_print = 0;
-
-       ameth->pkey_free = 0;
-       ameth->pkey_ctrl = 0;
+       }
 
        return ameth;
 
-err:
+ err:
        EVP_PKEY_asn1_free(ameth);
        return NULL;
 }
@@ -390,6 +357,7 @@ EVP_PKEY_asn1_copy(EVP_PKEY_ASN1_METHOD 
        dst->param_copy = src->param_copy;
        dst->param_cmp = src->param_cmp;
        dst->param_print = src->param_print;
+       dst->sig_print = src->sig_print;
 
        dst->pkey_free = src->pkey_free;
        dst->pkey_ctrl = src->pkey_ctrl;