OpenSSL: don't use direct access to the internal of EVP_MD_CTX

OpenSSL 1.1 does not allow us to directly access the internal of
any data type, including EVP_MD_CTX. We have to use the defined
functions to do so.

Compatibility with OpenSSL 1.0 is kept by defining the corresponding
functions when they are not found in the library.

Signed-off-by: Emmanuel Deloget <logout@free.fr>
Acked-by: Steffan Karger <steffan.karger@fox-it.com>
Message-Id: <20170612134330.20971-6-logout@free.fr>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg14793.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>

1 files changed, 43 insertions, 0 deletions

diff --git a/src/openvpn/openssl_compat.h b/src/openvpn/openssl_compat.h
index eeacb52..3d8fad1 100644
--- a/src/openvpn/openssl_compat.h
+++ b/src/openvpn/openssl_compat.h
@@ -45,6 +45,49 @@
 #include <openssl/ssl.h>
 #include <openssl/x509.h>
 
+#if !defined(HAVE_EVP_MD_CTX_RESET)
+/**
+ * Reset a message digest context
+ *
+ * @param ctx                 The message digest context
+ * @return                    1 on success, 0 on error
+ */
+static inline int
+EVP_MD_CTX_reset(EVP_MD_CTX *ctx)
+{
+    EVP_MD_CTX_cleanup(ctx);
+    return 1;
+}
+#endif
+
+#if !defined(HAVE_EVP_MD_CTX_FREE)
+/**
+ * Free an existing message digest context
+ *
+ * @param ctx                 The message digest context
+ */
+static inline void
+EVP_MD_CTX_free(EVP_MD_CTX *ctx)
+{
+    free(ctx);
+}
+#endif
+
+#if !defined(HAVE_EVP_MD_CTX_NEW)
+/**
+ * Allocate a new message digest object
+ *
+ * @return                    A zero'ed message digest object
+ */
+static inline EVP_MD_CTX *
+EVP_MD_CTX_new(void)
+{
+    EVP_MD_CTX *ctx = NULL;
+    ALLOC_OBJ_CLEAR(ctx, EVP_MD_CTX);
+    return ctx;
+}
+#endif
+
 #if !defined(HAVE_SSL_CTX_GET_DEFAULT_PASSWD_CB_USERDATA)
 /**
  * Fetch the default password callback user data from the SSL context