Use EVP_CTRL_AEAD_* instead EVP_CTRL_GCM_*

Use the modern names instead of the old GCM specific ones. AEAD instead
GCM makes especially sense when using Chacha20-Poly1305.

Signed-off-by: Arne Schwabe <arne@rfc2549.org>
Acked-by: Antonio Quartulli <antonio@openvpn.net>
Message-Id: <20210406162518.4075-4-arne@rfc2549.org>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg22050.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>

src/openvpn/crypto_openssl.c

@@ -792,7 +792,7 @@ cipher_ctx_iv_length(const EVP_CIPHER_CTX *ctx)
 int
 cipher_ctx_get_tag(EVP_CIPHER_CTX *ctx, uint8_t *tag_buf, int tag_size)
 {
-    return EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_GCM_GET_TAG, tag_size, tag_buf);
+    return EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_GET_TAG, tag_size, tag_buf);
 }
 
 int
@@ -853,7 +853,7 @@ cipher_ctx_final_check_tag(EVP_CIPHER_CTX *ctx, uint8_t *dst, int *dst_len,
                            uint8_t *tag, size_t tag_len)
 {
     ASSERT(tag_len < SIZE_MAX);
-    if (!EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_GCM_SET_TAG, tag_len, tag))
+    if (!EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_TAG, tag_len, tag))
     {
         return 0;
     }

src/openvpn/openssl_compat.h

@@ -46,6 +46,11 @@
 #include <openssl/ssl.h>
 #include <openssl/x509.h>
 
+#if (OPENSSL_VERSION_NUMBER < 0x10100000L || defined(LIBRESSL_VERSION_NUMBER)) && !defined(ENABLE_CRYPTO_WOLFSSL)
+#define EVP_CTRL_AEAD_SET_TAG EVP_CTRL_GCM_SET_TAG
+#define EVP_CTRL_AEAD_GET_TAG EVP_CTRL_GCM_GET_TAG
+#endif
+
 #if !defined(HAVE_EVP_MD_CTX_RESET)
 /**
  * Reset a message digest context