Add null digest implementation to the default provider

[openssl.git] / providers / implementations / digests / null_prov.c

diff --git a/providers/implementations/digests/null_prov.c b/providers/implementations/digests/null_prov.c
new file mode 100644 (file)
index 0000000..b220a19
--- /dev/null
+++ b/providers/implementations/digests/null_prov.c
@@ -0,0 +1,52 @@
+/*
+ * Copyright 2021 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
+ * in the file LICENSE in the source distribution or at
+ * https://www.openssl.org/source/license.html
+ */
+
+#include <openssl/crypto.h>
+#include "prov/digestcommon.h"
+#include "prov/implementations.h"
+
+typedef struct {
+    unsigned char nothing;
+} NULLMD_CTX;
+
+static int null_init(NULLMD_CTX *ctx)
+{
+    return 1;
+}
+
+static int null_update(NULLMD_CTX *ctx, const void *data, size_t datalen)
+{
+    return 1;
+}
+
+static int null_final(unsigned char *md, NULLMD_CTX *ctx)
+{
+    return 1;
+}
+
+/*
+ * We must override the PROV_FUNC_DIGEST_FINAL as dgstsize == 0
+ * and that would cause compilation warnings with the default implementation.
+ */
+#undef PROV_FUNC_DIGEST_FINAL
+#define PROV_FUNC_DIGEST_FINAL(name, dgstsize, fin)                            \
+static OSSL_FUNC_digest_final_fn name##_internal_final;                        \
+static int name##_internal_final(void *ctx, unsigned char *out, size_t *outl,  \
+                                 size_t outsz)                                 \
+{                                                                              \
+    if (ossl_prov_is_running() && fin(out, ctx)) {                             \
+        *outl = dgstsize;                                                      \
+        return 1;                                                              \
+    }                                                                          \
+    return 0;                                                                  \
+}
+
+IMPLEMENT_digest_functions(nullmd, NULLMD_CTX,
+                           0, 0, 0,
+                           null_init, null_update, null_final)