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/*
* Copyright (C) 2004-2007 Internet Systems Consortium, Inc. ("ISC")
* Copyright (C) 2000, 2001 Internet Software Consortium.
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
* REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
* INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
* LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
* OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
* PERFORMANCE OF THIS SOFTWARE.
*/
/* $Id: hmacmd5.c,v 1.14 2007-06-19 23:47:17 tbox Exp $ */
/*! \file
* This code implements the HMAC-MD5 keyed hash algorithm
* described in RFC2104.
*/
#include "config.h"
#include <isc/assertions.h>
#include <isc/hmacmd5.h>
#include <isc/md5.h>
#include <isc/string.h>
#include <isc/types.h>
#include <isc/util.h>
#define PADLEN 64
#define IPAD 0x36
#define OPAD 0x5C
/*!
* Start HMAC-MD5 process. Initialize an md5 context and digest the key.
*/
void
isc_hmacmd5_init(isc_hmacmd5_t *ctx, const unsigned char *key,
unsigned int len)
{
unsigned char ipad[PADLEN];
int i;
memset(ctx->key, 0, sizeof(ctx->key));
if (len > sizeof(ctx->key)) {
isc_md5_t md5ctx;
isc_md5_init(&md5ctx);
isc_md5_update(&md5ctx, key, len);
isc_md5_final(&md5ctx, ctx->key);
} else
memcpy(ctx->key, key, len);
isc_md5_init(&ctx->md5ctx);
memset(ipad, IPAD, sizeof(ipad));
for (i = 0; i < PADLEN; i++)
ipad[i] ^= ctx->key[i];
isc_md5_update(&ctx->md5ctx, ipad, sizeof(ipad));
}
void
isc_hmacmd5_invalidate(isc_hmacmd5_t *ctx) {
isc_md5_invalidate(&ctx->md5ctx);
memset(ctx->key, 0, sizeof(ctx->key));
}
/*!
* Update context to reflect the concatenation of another buffer full
* of bytes.
*/
void
isc_hmacmd5_update(isc_hmacmd5_t *ctx, const unsigned char *buf,
unsigned int len)
{
isc_md5_update(&ctx->md5ctx, buf, len);
}
/*!
* Compute signature - finalize MD5 operation and reapply MD5.
*/
void
isc_hmacmd5_sign(isc_hmacmd5_t *ctx, unsigned char *digest) {
unsigned char opad[PADLEN];
int i;
isc_md5_final(&ctx->md5ctx, digest);
memset(opad, OPAD, sizeof(opad));
for (i = 0; i < PADLEN; i++)
opad[i] ^= ctx->key[i];
isc_md5_init(&ctx->md5ctx);
isc_md5_update(&ctx->md5ctx, opad, sizeof(opad));
isc_md5_update(&ctx->md5ctx, digest, ISC_MD5_DIGESTLENGTH);
isc_md5_final(&ctx->md5ctx, digest);
isc_hmacmd5_invalidate(ctx);
}
/*!
* Verify signature - finalize MD5 operation and reapply MD5, then
* compare to the supplied digest.
*/
isc_boolean_t
isc_hmacmd5_verify(isc_hmacmd5_t *ctx, unsigned char *digest) {
return (isc_hmacmd5_verify2(ctx, digest, ISC_MD5_DIGESTLENGTH));
}
isc_boolean_t
isc_hmacmd5_verify2(isc_hmacmd5_t *ctx, unsigned char *digest, size_t len) {
unsigned char newdigest[ISC_MD5_DIGESTLENGTH];
REQUIRE(len <= ISC_MD5_DIGESTLENGTH);
isc_hmacmd5_sign(ctx, newdigest);
return (ISC_TF(memcmp(digest, newdigest, len) == 0));
}
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