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

 * Copyright (c) 2008 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 <openssl/aead.h>

#include <assert.h>

#include <openssl/cipher.h>

#include <openssl/err.h>

#include <openssl/mem.h>

#include "../delocate.h"

#include "../modes/internal.h"

#include "../service_indicator/internal.h"

#include "internal.h"

struct ccm128_context {

  block128_f block;

  ctr128_f ctr;

  unsigned M, L;

};

struct ccm128_state {

  alignas(16) uint8_t nonce[16];

  alignas(16) uint8_t cmac[16];

};

static int CRYPTO_ccm128_init(struct 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;

}

static size_t CRYPTO_ccm128_max_input(const struct ccm128_context *ctx) {

  return ctx->L >= sizeof(size_t) ? SIZE_MAX

                                  : (((size_t)1) << (ctx->L * 8)) - 1;

}

static int ccm128_init_state(const struct 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[0] = (uint8_t)((L - 1) | ((M - 2) / 2) << 3);

  if (aad_len != 0) {

    state->nonce[0] |= 0x40;  // Set AAD Flag

  }

  OPENSSL_memcpy(&state->nonce[1], nonce, nonce_len);

  for (unsigned i = 0; i < L; i++) {

    state->nonce[15 - i] = (uint8_t)(plaintext_len >> (8 * i));

  }

  (*block)(state->nonce, state->cmac, 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[0] ^= (uint8_t)(aad_len_u64 >> 8);

      state->cmac[1] ^= (uint8_t)aad_len_u64;

      i = 2;

    } else if (aad_len_u64 <= 0xffffffff) {

      state->cmac[0] ^= 0xff;

      state->cmac[1] ^= 0xfe;

      state->cmac[2] ^= (uint8_t)(aad_len_u64 >> 24);

      state->cmac[3] ^= (uint8_t)(aad_len_u64 >> 16);

      state->cmac[4] ^= (uint8_t)(aad_len_u64 >> 8);

      state->cmac[5] ^= (uint8_t)aad_len_u64;

      i = 6;

    } else {

      state->cmac[0] ^= 0xff;

      state->cmac[1] ^= 0xff;

      state->cmac[2] ^= (uint8_t)(aad_len_u64 >> 56);

      state->cmac[3] ^= (uint8_t)(aad_len_u64 >> 48);

      state->cmac[4] ^= (uint8_t)(aad_len_u64 >> 40);

      state->cmac[5] ^= (uint8_t)(aad_len_u64 >> 32);

      state->cmac[6] ^= (uint8_t)(aad_len_u64 >> 24);

      state->cmac[7] ^= (uint8_t)(aad_len_u64 >> 16);

      state->cmac[8] ^= (uint8_t)(aad_len_u64 >> 8);

      state->cmac[9] ^= (uint8_t)aad_len_u64;

      i = 10;

    }

    do {

      for (; i < 16 && aad_len != 0; i++) {

        state->cmac[i] ^= *aad;

        aad++;

        aad_len--;

      }

      (*block)(state->cmac, state->cmac, 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[0] &= 7;

  return 1;

}

static int ccm128_encrypt(const struct 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[15 - i] = 0;

  }

  state->nonce[15] = 1;

  uint8_t partial_buf[16];

  unsigned num = 0;

  if (ctx->ctr != NULL) {

    CRYPTO_ctr128_encrypt_ctr32(in, out, len, key, state->nonce, partial_buf,

                                &num, ctx->ctr);

  } else {

    CRYPTO_ctr128_encrypt(in, out, len, key, state->nonce, partial_buf, &num,

                          ctx->block);

  }

  return 1;

}

static int ccm128_compute_mac(const struct 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.

  while (len >= 16) {

    CRYPTO_xor16(state->cmac, state->cmac, in);

    (*block)(state->cmac, state->cmac, key);

    in += 16;

    len -= 16;

  }

  if (len > 0) {

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

      state->cmac[i] ^= in[i];

    }

    (*block)(state->cmac, state->cmac, key);

  }

  // Encrypt the MAC with counter zero.

  for (unsigned i = 0; i < ctx->L; i++) {

    state->nonce[15 - i] = 0;

  }

  alignas(16) uint8_t tmp[16];

  (*block)(state->nonce, tmp, key);

  CRYPTO_xor16(state->cmac, state->cmac, tmp);

  OPENSSL_memcpy(out_tag, state->cmac, tag_len);

  return 1;

}

static int CRYPTO_ccm128_encrypt(const struct 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);

}

static int CRYPTO_ccm128_decrypt(const struct 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);

}

#define EVP_AEAD_AES_CCM_MAX_TAG_LEN 16

struct aead_aes_ccm_ctx {

  union {

    double align;

    AES_KEY ks;

  } ks;

  struct ccm128_context ccm;

};

static_assert(sizeof(((EVP_AEAD_CTX *)NULL)->state) >=

                  sizeof(struct aead_aes_ccm_ctx),

              "AEAD state is too small");

static_assert(alignof(union evp_aead_ctx_st_state) >=

                  alignof(struct aead_aes_ccm_ctx),

              "AEAD state has insufficient alignment");

static int aead_aes_ccm_init(EVP_AEAD_CTX *ctx, const uint8_t *key,

                             size_t key_len, size_t tag_len, unsigned M,

                             unsigned L) {

  assert(M == EVP_AEAD_max_overhead(ctx->aead));

  assert(M == EVP_AEAD_max_tag_len(ctx->aead));

  assert(15 - L == EVP_AEAD_nonce_length(ctx->aead));

  if (key_len != EVP_AEAD_key_length(ctx->aead)) {

    OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_BAD_KEY_LENGTH);

    return 0;  // EVP_AEAD_CTX_init should catch this.

  }

  if (tag_len == EVP_AEAD_DEFAULT_TAG_LENGTH) {

    tag_len = M;

  }

  if (tag_len != M) {

    OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_TAG_TOO_LARGE);

    return 0;

  }

  struct aead_aes_ccm_ctx *ccm_ctx = (struct aead_aes_ccm_ctx *)&ctx->state;

  block128_f block;

  ctr128_f ctr = aes_ctr_set_key(&ccm_ctx->ks.ks, NULL, &block, key, key_len);

  ctx->tag_len = tag_len;

  if (!CRYPTO_ccm128_init(&ccm_ctx->ccm, &ccm_ctx->ks.ks, block, ctr, M, L)) {

    OPENSSL_PUT_ERROR(CIPHER, ERR_R_INTERNAL_ERROR);

    return 0;

  }

  return 1;

}

static void aead_aes_ccm_cleanup(EVP_AEAD_CTX *ctx) {}

static int aead_aes_ccm_seal_scatter(

    const EVP_AEAD_CTX *ctx, uint8_t *out, uint8_t *out_tag,

    size_t *out_tag_len, size_t max_out_tag_len, const uint8_t *nonce,

    size_t nonce_len, const uint8_t *in, size_t in_len, const uint8_t *extra_in,

    size_t extra_in_len, const uint8_t *ad, size_t ad_len) {

  const struct aead_aes_ccm_ctx *ccm_ctx =

      (struct aead_aes_ccm_ctx *)&ctx->state;

  if (in_len > CRYPTO_ccm128_max_input(&ccm_ctx->ccm)) {

    OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_TOO_LARGE);

    return 0;

  }

  if (max_out_tag_len < ctx->tag_len) {

    OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_BUFFER_TOO_SMALL);

    return 0;

  }

  if (nonce_len != EVP_AEAD_nonce_length(ctx->aead)) {

    OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_INVALID_NONCE_SIZE);

    return 0;

  }

  if (!CRYPTO_ccm128_encrypt(&ccm_ctx->ccm, &ccm_ctx->ks.ks, out, out_tag,

                             ctx->tag_len, nonce, nonce_len, in, in_len, ad,

                             ad_len)) {

    OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_TOO_LARGE);

    return 0;

  }

  *out_tag_len = ctx->tag_len;

  AEAD_CCM_verify_service_indicator(ctx);

  return 1;

}

static int aead_aes_ccm_open_gather(const EVP_AEAD_CTX *ctx, uint8_t *out,

                                    const uint8_t *nonce, size_t nonce_len,

                                    const uint8_t *in, size_t in_len,

                                    const uint8_t *in_tag, size_t in_tag_len,

                                    const uint8_t *ad, size_t ad_len) {

  const struct aead_aes_ccm_ctx *ccm_ctx =

      (struct aead_aes_ccm_ctx *)&ctx->state;

  if (in_len > CRYPTO_ccm128_max_input(&ccm_ctx->ccm)) {

    OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_TOO_LARGE);

    return 0;

  }

  if (nonce_len != EVP_AEAD_nonce_length(ctx->aead)) {

    OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_INVALID_NONCE_SIZE);

    return 0;

  }

  if (in_tag_len != ctx->tag_len) {

    OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_BAD_DECRYPT);

    return 0;

  }

  uint8_t tag[EVP_AEAD_AES_CCM_MAX_TAG_LEN];

  assert(ctx->tag_len <= EVP_AEAD_AES_CCM_MAX_TAG_LEN);

  if (!CRYPTO_ccm128_decrypt(&ccm_ctx->ccm, &ccm_ctx->ks.ks, out, tag,

                             ctx->tag_len, nonce, nonce_len, in, in_len, ad,

                             ad_len)) {

    OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_TOO_LARGE);

    return 0;

  }

  if (CRYPTO_memcmp(tag, in_tag, ctx->tag_len) != 0) {

    OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_BAD_DECRYPT);

    return 0;

  }

  AEAD_CCM_verify_service_indicator(ctx);

  return 1;

}

static int aead_aes_ccm_bluetooth_init(EVP_AEAD_CTX *ctx, const uint8_t *key,

                                       size_t key_len, size_t tag_len) {

  return aead_aes_ccm_init(ctx, key, key_len, tag_len, 4, 2);

}

DEFINE_METHOD_FUNCTION(EVP_AEAD, EVP_aead_aes_128_ccm_bluetooth) {

  memset(out, 0, sizeof(EVP_AEAD));

  out->key_len = 16;

  out->nonce_len = 13;

  out->overhead = 4;

  out->max_tag_len = 4;

  out->init = aead_aes_ccm_bluetooth_init;

  out->cleanup = aead_aes_ccm_cleanup;

  out->seal_scatter = aead_aes_ccm_seal_scatter;

  out->open_gather = aead_aes_ccm_open_gather;

}

static int aead_aes_ccm_bluetooth_8_init(EVP_AEAD_CTX *ctx, const uint8_t *key,

                                         size_t key_len, size_t tag_len) {

  return aead_aes_ccm_init(ctx, key, key_len, tag_len, 8, 2);

}

DEFINE_METHOD_FUNCTION(EVP_AEAD, EVP_aead_aes_128_ccm_bluetooth_8) {

  memset(out, 0, sizeof(EVP_AEAD));

  out->key_len = 16;

  out->nonce_len = 13;

  out->overhead = 8;

  out->max_tag_len = 8;

  out->init = aead_aes_ccm_bluetooth_8_init;

  out->cleanup = aead_aes_ccm_cleanup;

  out->seal_scatter = aead_aes_ccm_seal_scatter;

  out->open_gather = aead_aes_ccm_open_gather;

}

static int aead_aes_ccm_matter_init(EVP_AEAD_CTX *ctx, const uint8_t *key,

                                    size_t key_len, size_t tag_len) {

  return aead_aes_ccm_init(ctx, key, key_len, tag_len, 16, 2);

}

DEFINE_METHOD_FUNCTION(EVP_AEAD, EVP_aead_aes_128_ccm_matter) {

  memset(out, 0, sizeof(EVP_AEAD));

  out->key_len = 16;

  out->nonce_len = 13;

  out->overhead = 16;

  out->max_tag_len = 16;

  out->init = aead_aes_ccm_matter_init;

  out->cleanup = aead_aes_ccm_cleanup;

  out->seal_scatter = aead_aes_ccm_seal_scatter;

  out->open_gather = aead_aes_ccm_open_gather;

}