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/* ====================================================================
* 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,
* 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 <assert.h>
#include <string.h>
#include <openssl/cpu.h>
#include <openssl/mem.h>
#include "../../internal.h"
#include "internal.h"
struct ccm128_state {
union {
uint64_t u[2];
uint8_t c[16];
} nonce, cmac;
};
int CRYPTO_ccm128_init(CCM128_CONTEXT *ctx, const AES_KEY *key,
block128_f block, ctr128_f ctr, unsigned M, unsigned L) {
if (M < 4 || M > 16 || (M & 1) != 0 || L < 2 || L > 8) {
return 0;
}
ctx->block = block;
ctx->ctr = ctr;
ctx->M = M;
ctx->L = L;
return 1;
}
size_t CRYPTO_ccm128_max_input(const CCM128_CONTEXT *ctx) {
return ctx->L >= sizeof(size_t) ? (size_t)-1
: (((size_t)1) << (ctx->L * 8)) - 1;
}
static int ccm128_init_state(const CCM128_CONTEXT *ctx,
struct ccm128_state *state, const AES_KEY *key,
const uint8_t *nonce, size_t nonce_len,
const uint8_t *aad, size_t aad_len,
size_t plaintext_len) {
const block128_f block = ctx->block;
const unsigned M = ctx->M;
const unsigned L = ctx->L;
// |L| determines the expected |nonce_len| and the limit for |plaintext_len|.
if (plaintext_len > CRYPTO_ccm128_max_input(ctx) ||
nonce_len != 15 - L) {
return 0;
}
// Assemble the first block for computing the MAC.
OPENSSL_memset(state, 0, sizeof(*state));
state->nonce.c[0] = (uint8_t)((L - 1) | ((M - 2) / 2) << 3);
if (aad_len != 0) {
state->nonce.c[0] |= 0x40; // Set AAD Flag
}
OPENSSL_memcpy(&state->nonce.c[1], nonce, nonce_len);
for (unsigned i = 0; i < L; i++) {
state->nonce.c[15 - i] = (uint8_t)(plaintext_len >> (8 * i));
}
(*block)(state->nonce.c, state->cmac.c, key);
size_t blocks = 1;
if (aad_len != 0) {
unsigned i;
// Cast to u64 to avoid the compiler complaining about invalid shifts.
uint64_t aad_len_u64 = aad_len;
if (aad_len_u64 < 0x10000 - 0x100) {
state->cmac.c[0] ^= (uint8_t)(aad_len_u64 >> 8);
state->cmac.c[1] ^= (uint8_t)aad_len_u64;
i = 2;
} else if (aad_len_u64 <= 0xffffffff) {
state->cmac.c[0] ^= 0xff;
state->cmac.c[1] ^= 0xfe;
state->cmac.c[2] ^= (uint8_t)(aad_len_u64 >> 24);
state->cmac.c[3] ^= (uint8_t)(aad_len_u64 >> 16);
state->cmac.c[4] ^= (uint8_t)(aad_len_u64 >> 8);
state->cmac.c[5] ^= (uint8_t)aad_len_u64;
i = 6;
} else {
state->cmac.c[0] ^= 0xff;
state->cmac.c[1] ^= 0xff;
state->cmac.c[2] ^= (uint8_t)(aad_len_u64 >> 56);
state->cmac.c[3] ^= (uint8_t)(aad_len_u64 >> 48);
state->cmac.c[4] ^= (uint8_t)(aad_len_u64 >> 40);
state->cmac.c[5] ^= (uint8_t)(aad_len_u64 >> 32);
state->cmac.c[6] ^= (uint8_t)(aad_len_u64 >> 24);
state->cmac.c[7] ^= (uint8_t)(aad_len_u64 >> 16);
state->cmac.c[8] ^= (uint8_t)(aad_len_u64 >> 8);
state->cmac.c[9] ^= (uint8_t)aad_len_u64;
i = 10;
}
do {
for (; i < 16 && aad_len != 0; i++) {
state->cmac.c[i] ^= *aad;
aad++;
aad_len--;
}
(*block)(state->cmac.c, state->cmac.c, key);
blocks++;
i = 0;
} while (aad_len != 0);
}
// Per RFC 3610, section 2.6, the total number of block cipher operations done
// must not exceed 2^61. There are two block cipher operations remaining per
// message block, plus one block at the end to encrypt the MAC.
size_t remaining_blocks = 2 * ((plaintext_len + 15) / 16) + 1;
if (plaintext_len + 15 < plaintext_len ||
remaining_blocks + blocks < blocks ||
(uint64_t) remaining_blocks + blocks > UINT64_C(1) << 61) {
return 0;
}
// Assemble the first block for encrypting and decrypting. The bottom |L|
// bytes are replaced with a counter and all bit the encoding of |L| is
// cleared in the first byte.
state->nonce.c[0] &= 7;
return 1;
}
static int ccm128_encrypt(const CCM128_CONTEXT *ctx, struct ccm128_state *state,
const AES_KEY *key, uint8_t *out, const uint8_t *in,
size_t len) {
// The counter for encryption begins at one.
for (unsigned i = 0; i < ctx->L; i++) {
state->nonce.c[15 - i] = 0;
}
state->nonce.c[15] = 1;
uint8_t partial_buf[16];
unsigned num = 0;
if (ctx->ctr != NULL) {
CRYPTO_ctr128_encrypt_ctr32(in, out, len, key, state->nonce.c, partial_buf,
&num, ctx->ctr);
} else {
CRYPTO_ctr128_encrypt(in, out, len, key, state->nonce.c, partial_buf, &num,
ctx->block);
}
return 1;
}
static int ccm128_compute_mac(const CCM128_CONTEXT *ctx,
struct ccm128_state *state, const AES_KEY *key,
uint8_t *out_tag, size_t tag_len,
const uint8_t *in, size_t len) {
block128_f block = ctx->block;
if (tag_len != ctx->M) {
return 0;
}
// Incorporate |in| into the MAC.
union {
uint64_t u[2];
uint8_t c[16];
} tmp;
while (len >= 16) {
OPENSSL_memcpy(tmp.c, in, 16);
state->cmac.u[0] ^= tmp.u[0];
state->cmac.u[1] ^= tmp.u[1];
(*block)(state->cmac.c, state->cmac.c, key);
in += 16;
len -= 16;
}
if (len > 0) {
for (size_t i = 0; i < len; i++) {
state->cmac.c[i] ^= in[i];
}
(*block)(state->cmac.c, state->cmac.c, key);
}
// Encrypt the MAC with counter zero.
for (unsigned i = 0; i < ctx->L; i++) {
state->nonce.c[15 - i] = 0;
}
(*block)(state->nonce.c, tmp.c, key);
state->cmac.u[0] ^= tmp.u[0];
state->cmac.u[1] ^= tmp.u[1];
OPENSSL_memcpy(out_tag, state->cmac.c, tag_len);
return 1;
}
int CRYPTO_ccm128_encrypt(const CCM128_CONTEXT *ctx, const AES_KEY *key,
uint8_t *out, uint8_t *out_tag, size_t tag_len,
const uint8_t *nonce, size_t nonce_len,
const uint8_t *in, size_t len, const uint8_t *aad,
size_t aad_len) {
struct ccm128_state state;
return ccm128_init_state(ctx, &state, key, nonce, nonce_len, aad, aad_len,
len) &&
ccm128_compute_mac(ctx, &state, key, out_tag, tag_len, in, len) &&
ccm128_encrypt(ctx, &state, key, out, in, len);
}
int CRYPTO_ccm128_decrypt(const CCM128_CONTEXT *ctx, const AES_KEY *key,
uint8_t *out, uint8_t *out_tag, size_t tag_len,
const uint8_t *nonce, size_t nonce_len,
const uint8_t *in, size_t len, const uint8_t *aad,
size_t aad_len) {
struct ccm128_state state;
return ccm128_init_state(ctx, &state, key, nonce, nonce_len, aad, aad_len,
len) &&
ccm128_encrypt(ctx, &state, key, out, in, len) &&
ccm128_compute_mac(ctx, &state, key, out_tag, tag_len, out, len);
}
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