From c8be59d5ec262084b335eceec2ab1db0a6dd133d Mon Sep 17 00:00:00 2001
From: Hans Nilsson <hans@erlang.org>
Date: Wed, 5 Jun 2019 10:09:37 +0200
Subject: crypto: Move mac compatibility functions to hmac.c and cmac.c

The ultimate goal is to get rid of compatibility with old cryptolib versions
so we could remove those compatibility files permanently.
---
 lib/crypto/c_src/hmac.c | 50 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)

(limited to 'lib/crypto/c_src/hmac.c')

diff --git a/lib/crypto/c_src/hmac.c b/lib/crypto/c_src/hmac.c
index 1a4f96e1d5..5e2c68bfee 100644
--- a/lib/crypto/c_src/hmac.c
+++ b/lib/crypto/c_src/hmac.c
@@ -18,6 +18,16 @@
  * %CopyrightEnd%
  */
 
+
+/*****************************************************************
+ *
+ * This file has functions for compatibility with cryptolibs
+ * lacking the EVP_Digest API.
+ *
+ * See mac.c for the implementation using the EVP interface.
+ *
+ ****************************************************************/
+
 #ifndef HAS_EVP_PKEY_CTX
 
 #include "hmac.h"
@@ -215,4 +225,44 @@ ERL_NIF_TERM hmac_final_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
     return ret;
 }
 
+
+
+int hmac_low_level(ErlNifEnv* env, const EVP_MD *md,
+                   ErlNifBinary key_bin, ErlNifBinary text,
+                   ErlNifBinary *ret_bin, int *ret_bin_alloc, ERL_NIF_TERM *return_term)
+{
+    unsigned int size_int;
+    size_t size;
+
+    /* Find the needed space */
+    if (HMAC(md,
+             key_bin.data, (int)key_bin.size,
+             text.data, text.size,
+             NULL, &size_int) == NULL)
+        {
+            *return_term = EXCP_ERROR(env, "Get HMAC size failed");
+            return 0;
+        }
+
+    size = (size_t)size_int; /* Otherwise "size" is unused in 0.9.8.... */
+    if (!enif_alloc_binary(size, ret_bin))
+        {
+            *return_term = EXCP_ERROR(env, "Alloc binary");
+            return 0;
+        }
+    *ret_bin_alloc = 1;
+
+    /* And do the real HMAC calc */
+    if (HMAC(md,
+             key_bin.data, (int)key_bin.size,
+             text.data, text.size,
+             ret_bin->data, &size_int) == NULL)
+        {
+            *return_term = EXCP_ERROR(env, "HMAC sign failed");
+            return 0;
+        }
+                    
+    return 1;
+}
+
 #endif
-- 
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