New function EVP_CIPHER_free()

This function re-implements EVP_CIPHER_meth_free(), but has a name that
isn't encumbered by legacy EVP_CIPHER construction functionality.

We also refactor most of EVP_CIPHER_meth_new() into an internal
evp_cipher_new() that's used when creating fetched methods.

EVP_CIPHER_meth_new() and EVP_CIPHER_meth_free() are rewritten in terms of
evp_cipher_new() and EVP_CIPHER_free().  This means that at any time, we can
deprecate all the EVP_CIPHER_meth_ functions with no harmful consequence.

Reviewed-by: Shane Lontis <shane.lontis@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/9758)

1 files changed, 12 insertions, 29 deletions

diff --git a/crypto/evp/cmeth_lib.c b/crypto/evp/cmeth_lib.c
index 51c9b6ece2..34e85f6366 100644
--- a/crypto/evp/cmeth_lib.c
+++ b/crypto/evp/cmeth_lib.c
@@ -16,28 +16,29 @@
 
 EVP_CIPHER *EVP_CIPHER_meth_new(int cipher_type, int block_size, int key_len)
 {
-    EVP_CIPHER *cipher = OPENSSL_zalloc(sizeof(EVP_CIPHER));
+    EVP_CIPHER *cipher = evp_cipher_new();
 
     if (cipher != NULL) {
         cipher->nid = cipher_type;
         cipher->block_size = block_size;
         cipher->key_len = key_len;
-        cipher->lock = CRYPTO_THREAD_lock_new();
-        if (cipher->lock == NULL) {
-            OPENSSL_free(cipher);
-            return NULL;
-        }
-        cipher->refcnt = 1;
     }
     return cipher;
 }
 
 EVP_CIPHER *EVP_CIPHER_meth_dup(const EVP_CIPHER *cipher)
 {
-    EVP_CIPHER *to = EVP_CIPHER_meth_new(cipher->nid, cipher->block_size,
-                                         cipher->key_len);
+    EVP_CIPHER *to = NULL;
 
-    if (to != NULL) {
+    /*
+     * Non-legacy EVP_CIPHERs can't be duplicated like this.
+     * Use EVP_CIPHER_up_ref() instead.
+     */
+    if (cipher->prov != NULL)
+        return NULL;
+
+    if ((to = EVP_CIPHER_meth_new(cipher->nid, cipher->block_size,
+                                  cipher->key_len)) == NULL) {
         CRYPTO_RWLOCK *lock = to->lock;
 
         memcpy(to, cipher, sizeof(*to));
@@ -48,25 +49,7 @@ EVP_CIPHER *EVP_CIPHER_meth_dup(const EVP_CIPHER *cipher)
 
 void EVP_CIPHER_meth_free(EVP_CIPHER *cipher)
 {
-    if (cipher != NULL) {
-        int i;
-
-        CRYPTO_DOWN_REF(&cipher->refcnt, &i, cipher->lock);
-        if (i > 0)
-            return;
-        ossl_provider_free(cipher->prov);
-        OPENSSL_free(cipher->name);
-        CRYPTO_THREAD_lock_free(cipher->lock);
-        OPENSSL_free(cipher);
-    }
-}
-
-int EVP_CIPHER_up_ref(EVP_CIPHER *cipher)
-{
-    int ref = 0;
-
-    CRYPTO_UP_REF(&cipher->refcnt, &ref, cipher->lock);
-    return 1;
+    EVP_CIPHER_free(cipher);
 }
 
 int EVP_CIPHER_meth_set_iv_length(EVP_CIPHER *cipher, int iv_len)