ccm128.c
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/*
* Copyright 2011-2016 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the OpenSSL license (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
#include <openssl/crypto.h>
#include "modes_lcl.h"
#include <string.h>
/*
* 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) {
#if defined(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);
#if defined(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) {
#if defined(STRICT_ALIGNMENT)
union {
u64 u[2];
u8 c[16];
} temp;
#endif
(*block) (ctx->nonce.c, scratch.c, key);
ctr64_inc(ctx->nonce.c);
#if defined(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;
}