/* $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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 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 * ====================================================================
 */

#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;
}