summaryrefslogtreecommitdiff
path: root/lib/hmac.c
diff options
context:
space:
mode:
Diffstat (limited to 'lib/hmac.c')
-rw-r--r--lib/hmac.c133
1 files changed, 133 insertions, 0 deletions
diff --git a/lib/hmac.c b/lib/hmac.c
new file mode 100644
index 000000000..4df6f79ad
--- /dev/null
+++ b/lib/hmac.c
@@ -0,0 +1,133 @@
+/***************************************************************************
+ * _ _ ____ _
+ * Project ___| | | | _ \| |
+ * / __| | | | |_) | |
+ * | (__| |_| | _ <| |___
+ * \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) 1998 - 2011, 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
+ *
+ ***************************************************************************/
+
+#include "setup.h"
+
+#ifndef CURL_DISABLE_CRYPTO_AUTH
+
+#include "curl_hmac.h"
+
+#define _MPRINTF_REPLACE /* use our functions only */
+#include <curl/mprintf.h>
+
+#include "curl_memory.h"
+/* The last #include file should be: */
+#include "memdebug.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)
+{
+ size_t i;
+ HMAC_context * ctxt;
+ unsigned char * hkey;
+ unsigned char b;
+
+ /* Create HMAC context. */
+ i = sizeof *ctxt + 2 * hashparams->hmac_ctxtsize +
+ hashparams->hmac_resultlen;
+ ctxt = 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 = (unsigned char)(*key ^ hmac_ipad);
+ (*hashparams->hmac_hupdate)(ctxt->hmac_hashctxt1, &b, 1);
+ b = (unsigned char)(*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 /* CURL_DISABLE_CRYPTO_AUTH */