From 4bfe07640c93f8dfd3af4bb76c8346ef4a129cc8 Mon Sep 17 00:00:00 2001
From: monnerat <pm@datasphere.ch>
Date: Mon, 19 Apr 2010 11:16:30 +0200
Subject: Implement SMTP authentication

---
 lib/hmac.c | 123 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 123 insertions(+)
 create mode 100644 lib/hmac.c

(limited to 'lib/hmac.c')

diff --git a/lib/hmac.c b/lib/hmac.c
new file mode 100644
index 000000000..1d3ea8342
--- /dev/null
+++ b/lib/hmac.c
@@ -0,0 +1,123 @@
+/***************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) 1998 - 2010, Daniel Stenberg, <daniel@haxx.se>, et al.
+ *
+ * This software is licensed as described in the file COPYING, which
+ * you should have received as part of this distribution. The terms
+ * are also available at http://curl.haxx.se/docs/copyright.html.
+ *
+ * You may opt to use, copy, modify, merge, publish, distribute and/or sell
+ * copies of the Software, and permit persons to whom the Software is
+ * furnished to do so, under the terms of the COPYING file.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ * RFC2104 Keyed-Hashing for Message Authentication
+ *
+ ***************************************************************************/
+
+#ifndef CURL_DISABLE_CRYPTO_AUTH
+
+#include "setup.h"
+#include "curl_hmac.h"
+
+/*
+ * Generic HMAC algorithm.
+ *
+ *   This module computes HMAC digests based on any hash function. Parameters
+ * and computing procedures are set-up dynamically at HMAC computation
+ * context initialisation.
+ */
+
+static const unsigned char hmac_ipad = 0x36;
+static const unsigned char hmac_opad = 0x5C;
+
+
+
+HMAC_context *
+Curl_HMAC_init(const HMAC_params * hashparams,
+               const unsigned char * key,
+               unsigned int keylen)
+{
+  unsigned int i;
+  HMAC_context * ctxt;
+  unsigned char * hkey;
+  unsigned char b;
+
+  /* Create HMAC context. */
+  i = sizeof *ctxt + 2 * hashparams->hmac_ctxtsize + hashparams->hmac_resultlen;
+  ctxt = (HMAC_context *) malloc(i);
+
+  if(!ctxt)
+    return ctxt;
+
+  ctxt->hmac_hash = hashparams;
+  ctxt->hmac_hashctxt1 = (void *) (ctxt + 1);
+  ctxt->hmac_hashctxt2 = (void *) ((char *) ctxt->hmac_hashctxt1 +
+      hashparams->hmac_ctxtsize);
+
+  /* If the key is too long, replace it by its hash digest. */
+  if(keylen > hashparams->hmac_maxkeylen) {
+    (*hashparams->hmac_hinit)(ctxt->hmac_hashctxt1);
+    (*hashparams->hmac_hupdate)(ctxt->hmac_hashctxt1, key, keylen);
+    hkey = (unsigned char *) ctxt->hmac_hashctxt2 + hashparams->hmac_ctxtsize;
+    (*hashparams->hmac_hfinal)(hkey, ctxt->hmac_hashctxt1);
+    key = hkey;
+    keylen = hashparams->hmac_resultlen;
+  }
+
+  /* Prime the two hash contexts with the modified key. */
+  (*hashparams->hmac_hinit)(ctxt->hmac_hashctxt1);
+  (*hashparams->hmac_hinit)(ctxt->hmac_hashctxt2);
+
+  for (i = 0; i < keylen; i++) {
+    b = *key ^ hmac_ipad;
+    (*hashparams->hmac_hupdate)(ctxt->hmac_hashctxt1, &b, 1);
+    b = *key++ ^ hmac_opad;
+    (*hashparams->hmac_hupdate)(ctxt->hmac_hashctxt2, &b, 1);
+  }
+
+  for (; i < hashparams->hmac_maxkeylen; i++) {
+    (*hashparams->hmac_hupdate)(ctxt->hmac_hashctxt1, &hmac_ipad, 1);
+    (*hashparams->hmac_hupdate)(ctxt->hmac_hashctxt2, &hmac_opad, 1);
+  }
+
+  /* Done, return pointer to HMAC context. */
+  return ctxt;
+}
+
+int Curl_HMAC_update(HMAC_context * ctxt,
+                     const unsigned char * data,
+                     unsigned int len)
+{
+  /* Update first hash calculation. */
+  (*ctxt->hmac_hash->hmac_hupdate)(ctxt->hmac_hashctxt1, data, len);
+  return 0;
+}
+
+
+int Curl_HMAC_final(HMAC_context * ctxt, unsigned char * result)
+{
+  const HMAC_params * hashparams = ctxt->hmac_hash;
+
+  /* Do not get result if called with a null parameter: only release storage. */
+
+  if(!result)
+    result = (unsigned char *) ctxt->hmac_hashctxt2 +
+     ctxt->hmac_hash->hmac_ctxtsize;
+
+  (*hashparams->hmac_hfinal)(result, ctxt->hmac_hashctxt1);
+  (*hashparams->hmac_hupdate)(ctxt->hmac_hashctxt2,
+   result, hashparams->hmac_resultlen);
+  (*hashparams->hmac_hfinal)(result, ctxt->hmac_hashctxt2);
+  free((char *) ctxt);
+  return 0;
+}
+
+#endif
-- 
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