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dtls-hmac.c
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dtls-hmac.c
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/*******************************************************************************
*
* Copyright (c) 2011, 2012, 2013, 2014, 2015 Olaf Bergmann (TZI) and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* and Eclipse Distribution License v. 1.0 which accompanies this distribution.
*
* The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
* and the Eclipse Distribution License is available at
* http://www.eclipse.org/org/documents/edl-v10.php.
*
* Contributors:
* Olaf Bergmann - initial API and implementation
* Hauke Mehrtens - memory optimization, ECC integration
*
*******************************************************************************/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "tinydtls.h"
#ifdef HAVE_ASSERT_H
#include <assert.h>
#else
#define assert(x)
#endif
#include "dtls-hmac.h"
#include "lib/memb.h"
/* Log configuration */
#define LOG_MODULE "dtls-hmac"
#define LOG_LEVEL LOG_LEVEL_DTLS
#include "dtls-log.h"
MEMB(hmac_context_storage, dtls_hmac_context_t, DTLS_HASH_MAX);
static inline dtls_hmac_context_t *
dtls_hmac_context_new() {
return (dtls_hmac_context_t *)memb_alloc(&hmac_context_storage);
}
static inline void
dtls_hmac_context_free(dtls_hmac_context_t *ctx) {
memb_free(&hmac_context_storage, ctx);
}
void
dtls_hmac_storage_init(void) {
memb_init(&hmac_context_storage);
}
void
dtls_hmac_update(dtls_hmac_context_t *ctx,
const unsigned char *input, size_t ilen) {
assert(ctx);
dtls_hash_update(&ctx->data, input, ilen);
}
dtls_hmac_context_t *
dtls_hmac_new(const unsigned char *key, size_t klen) {
dtls_hmac_context_t *ctx;
ctx = dtls_hmac_context_new();
if (ctx)
dtls_hmac_init(ctx, key, klen);
return ctx;
}
void
dtls_hmac_init(dtls_hmac_context_t *ctx, const unsigned char *key, size_t klen) {
int i;
assert(ctx);
memset(ctx, 0, sizeof(dtls_hmac_context_t));
if (klen > DTLS_HMAC_BLOCKSIZE) {
dtls_hash_init(&ctx->data);
dtls_hash_update(&ctx->data, key, klen);
dtls_hash_finalize(ctx->pad, &ctx->data);
} else
memcpy(ctx->pad, key, klen);
/* create ipad: */
for (i=0; i < DTLS_HMAC_BLOCKSIZE; ++i)
ctx->pad[i] ^= 0x36;
dtls_hash_init(&ctx->data);
dtls_hmac_update(ctx, ctx->pad, DTLS_HMAC_BLOCKSIZE);
/* create opad by xor-ing pad[i] with 0x36 ^ 0x5C: */
for (i=0; i < DTLS_HMAC_BLOCKSIZE; ++i)
ctx->pad[i] ^= 0x6A;
}
void
dtls_hmac_free(dtls_hmac_context_t *ctx) {
if (ctx)
dtls_hmac_context_free(ctx);
}
int
dtls_hmac_finalize(dtls_hmac_context_t *ctx, unsigned char *result) {
unsigned char buf[DTLS_HMAC_DIGEST_SIZE];
size_t len;
assert(ctx);
assert(result);
len = dtls_hash_finalize(buf, &ctx->data);
dtls_hash_init(&ctx->data);
dtls_hash_update(&ctx->data, ctx->pad, DTLS_HMAC_BLOCKSIZE);
dtls_hash_update(&ctx->data, buf, len);
len = dtls_hash_finalize(result, &ctx->data);
return len;
}
#ifdef HMAC_TEST
#include <stdio.h>
int main(int argc, char **argv) {
static unsigned char buf[DTLS_HMAC_DIGEST_SIZE];
size_t len, i;
dtls_hmac_context_t *ctx;
if (argc < 3) {
fprintf(stderr, "usage: %s key text", argv[0]);
return -1;
}
dtls_hmac_storage_init();
ctx = dtls_hmac_new(argv[1], strlen(argv[1]));
assert(ctx);
dtls_hmac_update(ctx, argv[2], strlen(argv[2]));
len = dtls_hmac_finalize(ctx, buf);
for(i = 0; i < len; i++)
printf("%02x", buf[i]);
printf("\n");
dtls_hmac_free(ctx);
return 0;
}
#endif