/* $OpenBSD: ccm128.c,v 1.5 2019/05/08 14:18:25 tb Exp $ */

/* ====================================================================

 * Copyright (c) 2011 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

 *    openssl-core@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,

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 * ====================================================================

 */

#include <openssl/crypto.h>

#include "modes_lcl.h"

#include <string.h>

#ifndef MODES_DEBUG

# ifndef NDEBUG

#  define NDEBUG

# endif

#endif

/* First you setup M and L parameters and pass the key schedule.

 * This is called once per session setup... */

void CRYPTO_ccm128_init(CCM128_CONTEXT *ctx,

  unsigned int M,unsigned int L,void *key,block128_f block)

{

  memset(ctx->nonce.c,0,sizeof(ctx->nonce.c));

  ctx->nonce.c[0] = ((u8)(L-1)&7) | (u8)(((M-2)/2)&7)<<3;

  ctx->blocks = 0;

  ctx->block = block;

  ctx->key = key;

}

/* !!! Following interfaces are to be called *once* per packet !!! */

/* Then you setup per-message nonce and pass the length of the message */

int CRYPTO_ccm128_setiv(CCM128_CONTEXT *ctx,

  const unsigned char *nonce,size_t nlen,size_t mlen)

{

  unsigned int L = ctx->nonce.c[0]&7; /* the L parameter */

  if (nlen<(14-L)) return -1;   /* nonce is too short */

  if (sizeof(mlen)==8 && L>=3) {

    ctx->nonce.c[8]  = (u8)(mlen>>(56%(sizeof(mlen)*8)));

    ctx->nonce.c[9]  = (u8)(mlen>>(48%(sizeof(mlen)*8)));

    ctx->nonce.c[10] = (u8)(mlen>>(40%(sizeof(mlen)*8)));

    ctx->nonce.c[11] = (u8)(mlen>>(32%(sizeof(mlen)*8)));

  }

  else

    ctx->nonce.u[1] = 0;

  ctx->nonce.c[12] = (u8)(mlen>>24);

  ctx->nonce.c[13] = (u8)(mlen>>16);

  ctx->nonce.c[14] = (u8)(mlen>>8);

  ctx->nonce.c[15] = (u8)mlen;

  ctx->nonce.c[0] &= ~0x40; /* clear Adata flag */

  memcpy(&ctx->nonce.c[1],nonce,14-L);

  return 0;

}

/* Then you pass additional authentication data, this is optional */

void CRYPTO_ccm128_aad(CCM128_CONTEXT *ctx,

  const unsigned char *aad,size_t alen)

{ unsigned int i;

  block128_f block = ctx->block;

  if (alen==0) return;

  ctx->nonce.c[0] |= 0x40;  /* set Adata flag */

  (*block)(ctx->nonce.c,ctx->cmac.c,ctx->key),

  ctx->blocks++;

  if (alen<(0x10000-0x100)) {

    ctx->cmac.c[0] ^= (u8)(alen>>8);

    ctx->cmac.c[1] ^= (u8)alen;

    i=2;

  }

  else if (sizeof(alen)==8 && alen>=(size_t)1<<(32%(sizeof(alen)*8))) {

    ctx->cmac.c[0] ^= 0xFF;

    ctx->cmac.c[1] ^= 0xFF;

    ctx->cmac.c[2] ^= (u8)(alen>>(56%(sizeof(alen)*8)));

    ctx->cmac.c[3] ^= (u8)(alen>>(48%(sizeof(alen)*8)));

    ctx->cmac.c[4] ^= (u8)(alen>>(40%(sizeof(alen)*8)));

    ctx->cmac.c[5] ^= (u8)(alen>>(32%(sizeof(alen)*8)));

    ctx->cmac.c[6] ^= (u8)(alen>>24);

    ctx->cmac.c[7] ^= (u8)(alen>>16);

    ctx->cmac.c[8] ^= (u8)(alen>>8);

    ctx->cmac.c[9] ^= (u8)alen;

    i=10;

  }

  else {

    ctx->cmac.c[0] ^= 0xFF;

    ctx->cmac.c[1] ^= 0xFE;

    ctx->cmac.c[2] ^= (u8)(alen>>24);

    ctx->cmac.c[3] ^= (u8)(alen>>16);

    ctx->cmac.c[4] ^= (u8)(alen>>8);

    ctx->cmac.c[5] ^= (u8)alen;

    i=6;

  }

  do {

    for(;i<16 && alen;++i,++aad,--alen)

      ctx->cmac.c[i] ^= *aad;

    (*block)(ctx->cmac.c,ctx->cmac.c,ctx->key),

    ctx->blocks++;

    i=0;

  } while (alen);

}

/* Finally you encrypt or decrypt the message */

/* counter part of nonce may not be larger than L*8 bits,

 * L is not larger than 8, therefore 64-bit counter... */

static void ctr64_inc(unsigned char *counter) {

  unsigned int n=8;

  u8  c;

  counter += 8;

  do {

    --n;

    c = counter[n];

    ++c;

    counter[n] = c;

    if (c) return;

  } while (n);

}

int CRYPTO_ccm128_encrypt(CCM128_CONTEXT *ctx,

  const unsigned char *inp, unsigned char *out,

  size_t len)

{

  size_t    n;

  unsigned int  i,L;

  unsigned char flags0  = ctx->nonce.c[0];

  block128_f  block = ctx->block;

  void *    key = ctx->key;

  union { u64 u[2]; u8 c[16]; } scratch;

  if (!(flags0&0x40))

    (*block)(ctx->nonce.c,ctx->cmac.c,key),

    ctx->blocks++;

  ctx->nonce.c[0] = L = flags0&7;

  for (n=0,i=15-L;i<15;++i) {

    n |= ctx->nonce.c[i];

    ctx->nonce.c[i]=0;

    n <<= 8;

  }

  n |= ctx->nonce.c[15];  /* reconstructed length */

  ctx->nonce.c[15]=1;

  if (n!=len) return -1; /* length mismatch */

  ctx->blocks += ((len+15)>>3)|1;

  if (ctx->blocks > (U64(1)<<61)) return -2; /* too much data */

  while (len>=16) {

#ifdef __STRICT_ALIGNMENT

    union { u64 u[2]; u8 c[16]; } temp;

    memcpy (temp.c,inp,16);

    ctx->cmac.u[0] ^= temp.u[0];

    ctx->cmac.u[1] ^= temp.u[1];

#else

    ctx->cmac.u[0] ^= ((u64*)inp)[0];

    ctx->cmac.u[1] ^= ((u64*)inp)[1];

#endif

    (*block)(ctx->cmac.c,ctx->cmac.c,key);

    (*block)(ctx->nonce.c,scratch.c,key);

    ctr64_inc(ctx->nonce.c);

#ifdef __STRICT_ALIGNMENT

    temp.u[0] ^= scratch.u[0];

    temp.u[1] ^= scratch.u[1];

    memcpy(out,temp.c,16);

#else

    ((u64*)out)[0] = scratch.u[0]^((u64*)inp)[0];

    ((u64*)out)[1] = scratch.u[1]^((u64*)inp)[1];

#endif

    inp += 16;

    out += 16;

    len -= 16;

  }

  if (len) {

    for (i=0; i<len; ++i) ctx->cmac.c[i] ^= inp[i];

    (*block)(ctx->cmac.c,ctx->cmac.c,key);

    (*block)(ctx->nonce.c,scratch.c,key);

    for (i=0; i<len; ++i) out[i] = scratch.c[i]^inp[i];

  }

  for (i=15-L;i<16;++i)

    ctx->nonce.c[i]=0;

  (*block)(ctx->nonce.c,scratch.c,key);

  ctx->cmac.u[0] ^= scratch.u[0];

  ctx->cmac.u[1] ^= scratch.u[1];

  ctx->nonce.c[0] = flags0;

  return 0;

}

int CRYPTO_ccm128_decrypt(CCM128_CONTEXT *ctx,

  const unsigned char *inp, unsigned char *out,

  size_t len)

{

  size_t    n;

  unsigned int  i,L;

  unsigned char flags0  = ctx->nonce.c[0];

  block128_f  block = ctx->block;

  void *    key = ctx->key;

  union { u64 u[2]; u8 c[16]; } scratch;

  if (!(flags0&0x40))

    (*block)(ctx->nonce.c,ctx->cmac.c,key);

  ctx->nonce.c[0] = L = flags0&7;

  for (n=0,i=15-L;i<15;++i) {

    n |= ctx->nonce.c[i];

    ctx->nonce.c[i]=0;

    n <<= 8;

  }

  n |= ctx->nonce.c[15];  /* reconstructed length */

  ctx->nonce.c[15]=1;

  if (n!=len) return -1;

  while (len>=16) {

#ifdef __STRICT_ALIGNMENT

    union { u64 u[2]; u8 c[16]; } temp;

#endif

    (*block)(ctx->nonce.c,scratch.c,key);

    ctr64_inc(ctx->nonce.c);

#ifdef __STRICT_ALIGNMENT

    memcpy (temp.c,inp,16);

    ctx->cmac.u[0] ^= (scratch.u[0] ^= temp.u[0]);

    ctx->cmac.u[1] ^= (scratch.u[1] ^= temp.u[1]);

    memcpy (out,scratch.c,16);

#else

    ctx->cmac.u[0] ^= (((u64*)out)[0] = scratch.u[0]^((u64*)inp)[0]);

    ctx->cmac.u[1] ^= (((u64*)out)[1] = scratch.u[1]^((u64*)inp)[1]);

#endif

    (*block)(ctx->cmac.c,ctx->cmac.c,key);

    inp += 16;

    out += 16;

    len -= 16;

  }

  if (len) {

    (*block)(ctx->nonce.c,scratch.c,key);

    for (i=0; i<len; ++i)

      ctx->cmac.c[i] ^= (out[i] = scratch.c[i]^inp[i]);

    (*block)(ctx->cmac.c,ctx->cmac.c,key);

  }

  for (i=15-L;i<16;++i)

    ctx->nonce.c[i]=0;

  (*block)(ctx->nonce.c,scratch.c,key);

  ctx->cmac.u[0] ^= scratch.u[0];

  ctx->cmac.u[1] ^= scratch.u[1];

  ctx->nonce.c[0] = flags0;

  return 0;

}

static void ctr64_add (unsigned char *counter,size_t inc)

{ size_t n=8, val=0;

  counter += 8;

  do {

    --n;

    val += counter[n] + (inc&0xff);

    counter[n] = (unsigned char)val;

    val >>= 8;  /* carry bit */

    inc >>= 8;

  } while(n && (inc || val));

}

int CRYPTO_ccm128_encrypt_ccm64(CCM128_CONTEXT *ctx,

  const unsigned char *inp, unsigned char *out,

  size_t len,ccm128_f stream)

{

  size_t    n;

  unsigned int  i,L;

  unsigned char flags0  = ctx->nonce.c[0];

  block128_f  block = ctx->block;

  void *    key = ctx->key;

  union { u64 u[2]; u8 c[16]; } scratch;

  if (!(flags0&0x40))

    (*block)(ctx->nonce.c,ctx->cmac.c,key),

    ctx->blocks++;

  ctx->nonce.c[0] = L = flags0&7;

  for (n=0,i=15-L;i<15;++i) {

    n |= ctx->nonce.c[i];

    ctx->nonce.c[i]=0;

    n <<= 8;

  }

  n |= ctx->nonce.c[15];  /* reconstructed length */

  ctx->nonce.c[15]=1;

  if (n!=len) return -1; /* length mismatch */

  ctx->blocks += ((len+15)>>3)|1;

  if (ctx->blocks > (U64(1)<<61)) return -2; /* too much data */

  if ((n=len/16)) {

    (*stream)(inp,out,n,key,ctx->nonce.c,ctx->cmac.c);

    n   *= 16;

    inp += n;

    out += n;

    len -= n;

    if (len) ctr64_add(ctx->nonce.c,n/16);

  }

  if (len) {

    for (i=0; i<len; ++i) ctx->cmac.c[i] ^= inp[i];

    (*block)(ctx->cmac.c,ctx->cmac.c,key);

    (*block)(ctx->nonce.c,scratch.c,key);

    for (i=0; i<len; ++i) out[i] = scratch.c[i]^inp[i];

  }

  for (i=15-L;i<16;++i)

    ctx->nonce.c[i]=0;

  (*block)(ctx->nonce.c,scratch.c,key);

  ctx->cmac.u[0] ^= scratch.u[0];

  ctx->cmac.u[1] ^= scratch.u[1];

  ctx->nonce.c[0] = flags0;

  return 0;

}

int CRYPTO_ccm128_decrypt_ccm64(CCM128_CONTEXT *ctx,

  const unsigned char *inp, unsigned char *out,

  size_t len,ccm128_f stream)

{

  size_t    n;

  unsigned int  i,L;

  unsigned char flags0  = ctx->nonce.c[0];

  block128_f  block = ctx->block;

  void *    key = ctx->key;

  union { u64 u[2]; u8 c[16]; } scratch;

  if (!(flags0&0x40))

    (*block)(ctx->nonce.c,ctx->cmac.c,key);

  ctx->nonce.c[0] = L = flags0&7;

  for (n=0,i=15-L;i<15;++i) {

    n |= ctx->nonce.c[i];

    ctx->nonce.c[i]=0;

    n <<= 8;

  }

  n |= ctx->nonce.c[15];  /* reconstructed length */

  ctx->nonce.c[15]=1;

  if (n!=len) return -1;

  if ((n=len/16)) {

    (*stream)(inp,out,n,key,ctx->nonce.c,ctx->cmac.c);

    n   *= 16;

    inp += n;

    out += n;

    len -= n;

    if (len) ctr64_add(ctx->nonce.c,n/16);

  }

  if (len) {

    (*block)(ctx->nonce.c,scratch.c,key);

    for (i=0; i<len; ++i)

      ctx->cmac.c[i] ^= (out[i] = scratch.c[i]^inp[i]);

    (*block)(ctx->cmac.c,ctx->cmac.c,key);

  }

  for (i=15-L;i<16;++i)

    ctx->nonce.c[i]=0;

  (*block)(ctx->nonce.c,scratch.c,key);

  ctx->cmac.u[0] ^= scratch.u[0];

  ctx->cmac.u[1] ^= scratch.u[1];

  ctx->nonce.c[0] = flags0;

  return 0;

}

size_t CRYPTO_ccm128_tag(CCM128_CONTEXT *ctx,unsigned char *tag,size_t len)

{ unsigned int M = (ctx->nonce.c[0]>>3)&7;  /* the M parameter */

  M *= 2; M += 2;

  if (len != M) return 0;

  memcpy(tag,ctx->cmac.c,M);

  return M;

}