Fix regression of EVP_PKEY_CTX_add1_hkdf_info() with older providers

If there is no get_ctx_params() implemented in the key exchange
provider implementation the fallback will not work. Instead
check the gettable_ctx_params() to see if the fallback should be
performed.

Fixes openssl#24611

crypto/evp/pmeth_lib.c

@@ -1008,6 +1008,7 @@ static int evp_pkey_ctx_add1_octet_string(EVP_PKEY_CTX *ctx, int fallback,
  int datalen)
 {
  OSSL_PARAM os_params[2];
+ const OSSL_PARAM *gettables;
  unsigned char *info = NULL;
  size_t info_len = 0;
  size_t info_alloc = 0;
@@ -1031,16 +1032,22 @@ static int evp_pkey_ctx_add1_octet_string(EVP_PKEY_CTX *ctx, int fallback,
  return 1;
  }
 
+ /* Check for older provider that doesn't support getting this parameter */
+ gettables = EVP_PKEY_CTX_gettable_params(ctx);
+ if (gettables == NULL || OSSL_PARAM_locate_const(gettables, param) == NULL)
+ return evp_pkey_ctx_set1_octet_string(ctx, fallback, param, op, ctrl,
+ data, datalen);
+
  /* Get the original value length */
  os_params[0] = OSSL_PARAM_construct_octet_string(param, NULL, 0);
  os_params[1] = OSSL_PARAM_construct_end();
 
  if (!EVP_PKEY_CTX_get_params(ctx, os_params))
  return 0;
 
- /* Older provider that doesn't support getting this parameter */
+ /* This should not happen but check to be sure. */
  if (os_params[0].return_size == OSSL_PARAM_UNMODIFIED)
- return evp_pkey_ctx_set1_octet_string(ctx, fallback, param, op, ctrl, data, datalen);
+ return 0;
 
  info_alloc = os_params[0].return_size + datalen;
  if (info_alloc == 0)