/* 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)

{

    if (!ctx)

        return;

    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;

        }

        /* Switch to FIPS cipher implementation if possible */

        if (cipher != NULL) {

            const EVP_CIPHER *fcipher;

            fcipher = FIPS_get_cipherbynid(EVP_CIPHER_nid(cipher));

            if (fcipher != NULL)

                cipher = fcipher;

        }

        /*

         * 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);

}