Add generic EVP method fetcher

This is an interface between Core dispatch table fetching and
EVP_{method}_fetch().  All that's needed from the diverse method
fetchers are the functions to create a method structure from a
dispatch table, a function that ups the method reference counter and a
function to free the method (in case of failure).

This routine is internal to the EVP API andis therefore only made
accessible within crypto/evp, by including evp_locl.h

Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/8341)

1 files changed, 11 insertions, 1 deletions

diff --git a/crypto/evp/evp_locl.h b/crypto/evp/evp_locl.h
index 95a9d5c517..82e7bf8b11 100644
--- a/crypto/evp/evp_locl.h
+++ b/crypto/evp/evp_locl.h
@@ -1,5 +1,5 @@
 /*
- * Copyright 2000-2018 The OpenSSL Project Authors. All Rights Reserved.
+ * Copyright 2000-2019 The OpenSSL Project Authors. All Rights Reserved.
  *
  * Licensed under the Apache License 2.0 (the "License").  You may not use
  * this file except in compliance with the License.  You can obtain a copy
@@ -76,3 +76,13 @@ typedef struct evp_pbe_st EVP_PBE_CTL;
 DEFINE_STACK_OF(EVP_PBE_CTL)
 
 int is_partially_overlapping(const void *ptr1, const void *ptr2, int len);
+
+#include <openssl/ossl_typ.h>
+#include <openssl/core.h>
+
+void *evp_generic_fetch(OPENSSL_CTX *ctx, int operation_id,
+                        const char *algorithm, const char *properties,
+                        void *(*new_method)(int nid, const OSSL_DISPATCH *fns,
+                                            OSSL_PROVIDER *prov),
+                        int (*upref_method)(void *),
+                        void (*free_method)(void *));