/* $NetBSD: aesxcbcmac.c,v 1.3 2020/06/29 23:34:48 riastradh Exp $ */

/*
* Copyright (C) 1995, 1996, 1997, 1998 and 2003 WIDE 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. Neither the name of the project nor the names of its contributors
*    may be used to endorse or promote products derived from this software
*    without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS 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 PROJECT OR 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 <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: aesxcbcmac.c,v 1.3 2020/06/29 23:34:48 riastradh Exp $");

#include <sys/param.h>
#include <sys/systm.h>

#include <crypto/aes/aes.h>

#include <opencrypto/aesxcbcmac.h>

int
aes_xcbc_mac_init(void *vctx, const uint8_t *key, u_int16_t keylen)
{
       static const uint8_t k1seed[AES_BLOCKSIZE] =
           { 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1 };
       static const uint8_t k2seed[AES_BLOCKSIZE] =
           { 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2 };
       static const uint8_t k3seed[AES_BLOCKSIZE] =
           { 3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3 };
       struct aesenc r_ks;
       aesxcbc_ctx *ctx;
       uint8_t k1[AES_BLOCKSIZE];

       ctx = vctx;
       memset(ctx, 0, sizeof(*ctx));

       switch (keylen) {
       case 16:
               ctx->r_nr = aes_setenckey128(&r_ks, key);
               break;
       case 24:
               ctx->r_nr = aes_setenckey192(&r_ks, key);
               break;
       case 32:
               ctx->r_nr = aes_setenckey256(&r_ks, key);
               break;
       }
       aes_enc(&r_ks, k1seed, k1, ctx->r_nr);
       aes_enc(&r_ks, k2seed, ctx->k2, ctx->r_nr);
       aes_enc(&r_ks, k3seed, ctx->k3, ctx->r_nr);
       aes_setenckey128(&ctx->r_k1s, k1);

       explicit_memset(&r_ks, 0, sizeof(r_ks));
       explicit_memset(k1, 0, sizeof(k1));

       return 0;
}

int
aes_xcbc_mac_loop(void *vctx, const uint8_t *addr, u_int16_t len)
{
       uint8_t buf[AES_BLOCKSIZE];
       aesxcbc_ctx *ctx;
       const uint8_t *ep;
       int i;

       ctx = vctx;
       ep = addr + len;

       if (ctx->buflen == sizeof(ctx->buf)) {
               for (i = 0; i < sizeof(ctx->e); i++)
                       ctx->buf[i] ^= ctx->e[i];
               aes_enc(&ctx->r_k1s, ctx->buf, ctx->e, ctx->r_nr);
               ctx->buflen = 0;
       }
       if (ctx->buflen + len < sizeof(ctx->buf)) {
               memcpy(ctx->buf + ctx->buflen, addr, len);
               ctx->buflen += len;
               return 0;
       }
       if (ctx->buflen && ctx->buflen + len > sizeof(ctx->buf)) {
               memcpy(ctx->buf + ctx->buflen, addr,
                   sizeof(ctx->buf) - ctx->buflen);
               for (i = 0; i < sizeof(ctx->e); i++)
                       ctx->buf[i] ^= ctx->e[i];
               aes_enc(&ctx->r_k1s, ctx->buf, ctx->e, ctx->r_nr);
               addr += sizeof(ctx->buf) - ctx->buflen;
               ctx->buflen = 0;
       }
       /* due to the special processing for M[n], "=" case is not included */
       while (ep - addr > AES_BLOCKSIZE) {
               memcpy(buf, addr, AES_BLOCKSIZE);
               for (i = 0; i < sizeof(buf); i++)
                       buf[i] ^= ctx->e[i];
               aes_enc(&ctx->r_k1s, buf, ctx->e, ctx->r_nr);
               addr += AES_BLOCKSIZE;
       }
       if (addr < ep) {
               memcpy(ctx->buf + ctx->buflen, addr, ep - addr);
               ctx->buflen += ep - addr;
       }
       return 0;
}

void
aes_xcbc_mac_result(uint8_t *addr, void *vctx)
{
       uint8_t digest[AES_BLOCKSIZE];
       aesxcbc_ctx *ctx;
       int i;

       ctx = vctx;

       if (ctx->buflen == sizeof(ctx->buf)) {
               for (i = 0; i < sizeof(ctx->buf); i++) {
                       ctx->buf[i] ^= ctx->e[i];
                       ctx->buf[i] ^= ctx->k2[i];
               }
               aes_enc(&ctx->r_k1s, ctx->buf, digest, ctx->r_nr);
       } else {
               for (i = ctx->buflen; i < sizeof(ctx->buf); i++)
                       ctx->buf[i] = (i == ctx->buflen) ? 0x80 : 0x00;
               for (i = 0; i < sizeof(ctx->buf); i++) {
                       ctx->buf[i] ^= ctx->e[i];
                       ctx->buf[i] ^= ctx->k3[i];
               }
               aes_enc(&ctx->r_k1s, ctx->buf, digest, ctx->r_nr);
       }

       memcpy(addr, digest, sizeof(digest));
}

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