/* crypto/cmac/cmac.c */
/* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
* project.
*/
/* ====================================================================
* Copyright (c) 2010 The OpenSSL Project. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. All advertising materials mentioning features or use of this
* software must display the following acknowledgment:
* "This product includes software developed by the OpenSSL Project
* for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
*
* 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
* endorse or promote products derived from this software without
* prior written permission. For written permission, please contact
* licensing@OpenSSL.org.
*
* 5. Products derived from this software may not be called "OpenSSL"
* nor may "OpenSSL" appear in their names without prior written
* permission of the OpenSSL Project.
*
* 6. Redistributions of any form whatsoever must retain the following
* acknowledgment:
* "This product includes software developed by the OpenSSL Project
* for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
*
* THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
* EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
* ====================================================================
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "cryptlib.h"
#include <openssl/cmac.h>
#ifdef OPENSSL_FIPS
#include <openssl/fips.h>
#endif
struct CMAC_CTX_st
{
/* Cipher context to use */
EVP_CIPHER_CTX cctx;
/* Keys k1 and k2 */
unsigned char k1[EVP_MAX_BLOCK_LENGTH];
unsigned char k2[EVP_MAX_BLOCK_LENGTH];
/* Temporary block */
unsigned char tbl[EVP_MAX_BLOCK_LENGTH];
/* Last (possibly partial) block */
unsigned char last_block[EVP_MAX_BLOCK_LENGTH];
/* Number of bytes in last block: -1 means context not initialised */
int nlast_block;
};
/* Make temporary keys K1 and K2 */
static void make_kn(unsigned char *k1, unsigned char *l, int bl)
{
int i;
/* Shift block to left, including carry */
for (i = 0; i < bl; i++)
{
k1[i] = l[i] << 1;
if (i < bl - 1 && l[i + 1] & 0x80)
k1[i] |= 1;
}
/* If MSB set fixup with R */
if (l[0] & 0x80)
k1[bl - 1] ^= bl == 16 ? 0x87 : 0x1b;
}
CMAC_CTX *CMAC_CTX_new(void)
{
CMAC_CTX *ctx;
ctx = OPENSSL_malloc(sizeof(CMAC_CTX));
if (!ctx)
return NULL;
EVP_CIPHER_CTX_init(&ctx->cctx);
ctx->nlast_block = -1;
return ctx;
}
void CMAC_CTX_cleanup(CMAC_CTX *ctx)
{
#ifdef OPENSSL_FIPS
if (FIPS_mode() && !ctx->cctx.engine)
{
FIPS_cmac_ctx_cleanup(ctx);
return;
}
#endif
EVP_CIPHER_CTX_cleanup(&ctx->cctx);
OPENSSL_cleanse(ctx->tbl, EVP_MAX_BLOCK_LENGTH);
OPENSSL_cleanse(ctx->k1, EVP_MAX_BLOCK_LENGTH);
OPENSSL_cleanse(ctx->k2, EVP_MAX_BLOCK_LENGTH);
OPENSSL_cleanse(ctx->last_block, EVP_MAX_BLOCK_LENGTH);
ctx->nlast_block = -1;
}
EVP_CIPHER_CTX *CMAC_CTX_get0_cipher_ctx(CMAC_CTX *ctx)
{
return &ctx->cctx;
}
void CMAC_CTX_free(CMAC_CTX *ctx)
{
CMAC_CTX_cleanup(ctx);
OPENSSL_free(ctx);
}
int CMAC_CTX_copy(CMAC_CTX *out, const CMAC_CTX *in)
{
int bl;
if (in->nlast_block == -1)
return 0;
if (!EVP_CIPHER_CTX_copy(&out->cctx, &in->cctx))
return 0;
bl = EVP_CIPHER_CTX_block_size(&in->cctx);
memcpy(out->k1, in->k1, bl);
memcpy(out->k2, in->k2, bl);
memcpy(out->tbl, in->tbl, bl);
memcpy(out->last_block, in->last_block, bl);
out->nlast_block = in->nlast_block;
return 1;
}
int CMAC_Init(CMAC_CTX *ctx, const void *key, size_t keylen,
const EVP_CIPHER *cipher, ENGINE *impl)
{
static unsigned char zero_iv[EVP_MAX_BLOCK_LENGTH];
#ifdef OPENSSL_FIPS
if (FIPS_mode())
{
/* If we have an ENGINE need to allow non FIPS */
if ((impl || ctx->cctx.engine)
&& !(ctx->cctx.flags & EVP_CIPH_FLAG_NON_FIPS_ALLOW))
{
EVPerr(EVP_F_CMAC_INIT, EVP_R_DISABLED_FOR_FIPS);
return 0;
}
/* Other algorithm blocking will be done in FIPS_cmac_init,
* via FIPS_cipherinit().
*/
if (!impl && !ctx->cctx.engine)
return FIPS_cmac_init(ctx, key, keylen, cipher, NULL);
}
#endif
/* All zeros means restart */
if (!key && !cipher && !impl && keylen == 0)
{
/* Not initialised */
if (ctx->nlast_block == -1)
return 0;
if (!EVP_EncryptInit_ex(&ctx->cctx, NULL, NULL, NULL, zero_iv))
return 0;
memset(ctx->tbl, 0, EVP_CIPHER_CTX_block_size(&ctx->cctx));
ctx->nlast_block = 0;
return 1;
}
/* Initialiase context */
if (cipher && !EVP_EncryptInit_ex(&ctx->cctx, cipher, impl, NULL, NULL))
return 0;
/* Non-NULL key means initialisation complete */
if (key)
{
int bl;
if (!EVP_CIPHER_CTX_cipher(&ctx->cctx))
return 0;
if (!EVP_CIPHER_CTX_set_key_length(&ctx->cctx, keylen))
return 0;
if (!EVP_EncryptInit_ex(&ctx->cctx, NULL, NULL, key, zero_iv))
return 0;
bl = EVP_CIPHER_CTX_block_size(&ctx->cctx);
if (!EVP_Cipher(&ctx->cctx, ctx->tbl, zero_iv, bl))
return 0;
make_kn(ctx->k1, ctx->tbl, bl);
make_kn(ctx->k2, ctx->k1, bl);
OPENSSL_cleanse(ctx->tbl, bl);
/* Reset context again ready for first data block */
if (!EVP_EncryptInit_ex(&ctx->cctx, NULL, NULL, NULL, zero_iv))
return 0;
/* Zero tbl so resume works */
memset(ctx->tbl, 0, bl);
ctx->nlast_block = 0;
}
return 1;
}
int CMAC_Update(CMAC_CTX *ctx, const void *in, size_t dlen)
{
const unsigned char *data = in;
size_t bl;
#ifdef OPENSSL_FIPS
if (FIPS_mode() && !ctx->cctx.engine)
return FIPS_cmac_update(ctx, in, dlen);
#endif
if (ctx->nlast_block == -1)
return 0;
if (dlen == 0)
return 1;
bl = EVP_CIPHER_CTX_block_size(&ctx->cctx);
/* Copy into partial block if we need to */
if (ctx->nlast_block > 0)
{
size_t nleft;
nleft = bl - ctx->nlast_block;
if (dlen < nleft)
nleft = dlen;
memcpy(ctx->last_block + ctx->nlast_block, data, nleft);
dlen -= nleft;
ctx->nlast_block += nleft;
/* If no more to process return */
if (dlen == 0)
return 1;
data += nleft;
/* Else not final block so encrypt it */
if (!EVP_Cipher(&ctx->cctx, ctx->tbl, ctx->last_block,bl))
return 0;
}
/* Encrypt all but one of the complete blocks left */
while(dlen > bl)
{
if (!EVP_Cipher(&ctx->cctx, ctx->tbl, data, bl))
return 0;
dlen -= bl;
data += bl;
}
/* Copy any data left to last block buffer */
memcpy(ctx->last_block, data, dlen);
ctx->nlast_block = dlen;
return 1;
}
int CMAC_Final(CMAC_CTX *ctx, unsigned char *out, size_t *poutlen)
{
int i, bl, lb;
#ifdef OPENSSL_FIPS
if (FIPS_mode() && !ctx->cctx.engine)
return FIPS_cmac_final(ctx, out, poutlen);
#endif
if (ctx->nlast_block == -1)
return 0;
bl = EVP_CIPHER_CTX_block_size(&ctx->cctx);
*poutlen = (size_t)bl;
if (!out)
return 1;
lb = ctx->nlast_block;
/* Is last block complete? */
if (lb == bl)
{
for (i = 0; i < bl; i++)
out[i] = ctx->last_block[i] ^ ctx->k1[i];
}
else
{
ctx->last_block[lb] = 0x80;
if (bl - lb > 1)
memset(ctx->last_block + lb + 1, 0, bl - lb - 1);
for (i = 0; i < bl; i++)
out[i] = ctx->last_block[i] ^ ctx->k2[i];
}
if (!EVP_Cipher(&ctx->cctx, out, out, bl))
{
OPENSSL_cleanse(out, bl);
return 0;
}
return 1;
}
int CMAC_resume(CMAC_CTX *ctx)
{
if (ctx->nlast_block == -1)
return 0;
/* The buffer "tbl" containes the last fully encrypted block
* which is the last IV (or all zeroes if no last encrypted block).
* The last block has not been modified since CMAC_final().
* So reinitliasing using the last decrypted block will allow
* CMAC to continue after calling CMAC_Final().
*/
return EVP_EncryptInit_ex(&ctx->cctx, NULL, NULL, NULL, ctx->tbl);
}