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

 * Copyright (c) 2001-2011 The OpenSSL Project.  All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

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 * 3. All advertising materials mentioning features or use of this

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 *    "This product includes software developed by the OpenSSL Project

 *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"

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 * 5. Products derived from this software may not be called "OpenSSL"

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 *    acknowledgment:

 *    "This product includes software developed by the OpenSSL Project

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#include <openssl/aes.h>

#include <assert.h>

#include <limits.h>

#include <string.h>

#include <openssl/mem.h>

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

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

// kDefaultIV is the default IV value given in RFC 3394, 2.2.3.1.

static const uint8_t kDefaultIV[] = {

    0xa6, 0xa6, 0xa6, 0xa6, 0xa6, 0xa6, 0xa6, 0xa6,

};

static const unsigned kBound = 6;

int AES_wrap_key(const AES_KEY *key, const uint8_t *iv, uint8_t *out,

                 const uint8_t *in, size_t in_len) {

  // See RFC 3394, section 2.2.1. Additionally, note that section 2 requires the

  // plaintext be at least two 8-byte blocks.

  if (in_len > INT_MAX - 8 || in_len < 16 || in_len % 8 != 0) {

    return -1;

  }

  if (iv == NULL) {

    iv = kDefaultIV;

  }

  OPENSSL_memmove(out + 8, in, in_len);

  uint8_t A[AES_BLOCK_SIZE];

  OPENSSL_memcpy(A, iv, 8);

  size_t n = in_len / 8;

  for (unsigned j = 0; j < kBound; j++) {

    for (size_t i = 1; i <= n; i++) {

      OPENSSL_memcpy(A + 8, out + 8 * i, 8);

      AES_encrypt(A, A, key);

      uint32_t t = (uint32_t)(n * j + i);

      A[7] ^= t & 0xff;

      A[6] ^= (t >> 8) & 0xff;

      A[5] ^= (t >> 16) & 0xff;

      A[4] ^= (t >> 24) & 0xff;

      OPENSSL_memcpy(out + 8 * i, A + 8, 8);

    }

  }

  OPENSSL_memcpy(out, A, 8);

  FIPS_service_indicator_update_state();

  return (int)in_len + 8;

}

// aes_unwrap_key_inner performs steps one and two from

// https://tools.ietf.org/html/rfc3394#section-2.2.2

static int aes_unwrap_key_inner(const AES_KEY *key, uint8_t *out,

                                uint8_t out_iv[8], const uint8_t *in,

                                size_t in_len) {

  // See RFC 3394, section 2.2.2. Additionally, note that section 2 requires the

  // plaintext be at least two 8-byte blocks, so the ciphertext must be at least

  // three blocks.

  if (in_len > INT_MAX || in_len < 24 || in_len % 8 != 0) {

    return 0;

  }

  uint8_t A[AES_BLOCK_SIZE];

  OPENSSL_memcpy(A, in, 8);

  OPENSSL_memmove(out, in + 8, in_len - 8);

  size_t n = (in_len / 8) - 1;

  for (unsigned j = kBound - 1; j < kBound; j--) {

    for (size_t i = n; i > 0; i--) {

      uint32_t t = (uint32_t)(n * j + i);

      A[7] ^= t & 0xff;

      A[6] ^= (t >> 8) & 0xff;

      A[5] ^= (t >> 16) & 0xff;

      A[4] ^= (t >> 24) & 0xff;

      OPENSSL_memcpy(A + 8, out + 8 * (i - 1), 8);

      AES_decrypt(A, A, key);

      OPENSSL_memcpy(out + 8 * (i - 1), A + 8, 8);

    }

  }

  memcpy(out_iv, A, 8);

  return 1;

}

int AES_unwrap_key(const AES_KEY *key, const uint8_t *iv, uint8_t *out,

                   const uint8_t *in, size_t in_len) {

  uint8_t calculated_iv[8];

  if (!aes_unwrap_key_inner(key, out, calculated_iv, in, in_len)) {

    return -1;

  }

  if (iv == NULL) {

    iv = kDefaultIV;

  }

  if (CRYPTO_memcmp(calculated_iv, iv, 8) != 0) {

    return -1;

  }

  FIPS_service_indicator_update_state();

  return (int)in_len - 8;

}

// kPaddingConstant is used in Key Wrap with Padding. See

// https://tools.ietf.org/html/rfc5649#section-3

static const uint8_t kPaddingConstant[4] = {0xa6, 0x59, 0x59, 0xa6};

int AES_wrap_key_padded(const AES_KEY *key, uint8_t *out, size_t *out_len,

                        size_t max_out, const uint8_t *in, size_t in_len) {

  // See https://tools.ietf.org/html/rfc5649#section-4.1

  const uint64_t in_len64 = in_len;

  const size_t padded_len = (in_len + 7) & ~7;

  *out_len = 0;

  if (in_len == 0 || in_len64 > 0xffffffffu || in_len + 7 < in_len ||

      padded_len + 8 < padded_len || max_out < padded_len + 8) {

    return 0;

  }

  uint8_t block[AES_BLOCK_SIZE];

  memcpy(block, kPaddingConstant, sizeof(kPaddingConstant));

  CRYPTO_store_u32_be(block + 4, (uint32_t)in_len);

  if (in_len <= 8) {

    memset(block + 8, 0, 8);

    memcpy(block + 8, in, in_len);

    AES_encrypt(block, out, key);

    *out_len = AES_BLOCK_SIZE;

    return 1;

  }

  uint8_t *padded_in = OPENSSL_malloc(padded_len);

  if (padded_in == NULL) {

    return 0;

  }

  assert(padded_len >= 8);

  memset(padded_in + padded_len - 8, 0, 8);

  memcpy(padded_in, in, in_len);

  FIPS_service_indicator_lock_state();

  const int ret = AES_wrap_key(key, block, out, padded_in, padded_len);

  FIPS_service_indicator_unlock_state();

  OPENSSL_free(padded_in);

  if (ret < 0) {

    return 0;

  }

  *out_len = ret;

  FIPS_service_indicator_update_state();

  return 1;

}

int AES_unwrap_key_padded(const AES_KEY *key, uint8_t *out, size_t *out_len,

                          size_t max_out, const uint8_t *in, size_t in_len) {

  *out_len = 0;

  if (in_len < AES_BLOCK_SIZE || max_out < in_len - 8) {

    return 0;

  }

  uint8_t iv[8];

  if (in_len == AES_BLOCK_SIZE) {

    uint8_t block[AES_BLOCK_SIZE];

    AES_decrypt(in, block, key);

    memcpy(iv, block, sizeof(iv));

    memcpy(out, block + 8, 8);

  } else if (!aes_unwrap_key_inner(key, out, iv, in, in_len)) {

    return 0;

  }

  assert(in_len % 8 == 0);

  crypto_word_t ok = constant_time_eq_int(

      CRYPTO_memcmp(iv, kPaddingConstant, sizeof(kPaddingConstant)), 0);

  const size_t claimed_len = CRYPTO_load_u32_be(iv + 4);

  ok &= ~constant_time_is_zero_w(claimed_len);

  ok &= constant_time_eq_w((claimed_len - 1) >> 3, (in_len - 9) >> 3);

  // Check that padding bytes are all zero.

  for (size_t i = in_len - 15; i < in_len - 8; i++) {

    ok &= constant_time_is_zero_w(constant_time_ge_8(i, claimed_len) & out[i]);

  }

  *out_len = constant_time_select_w(ok, claimed_len, 0);

  const int ret = ok & 1;

  if (ret) {

    FIPS_service_indicator_update_state();

  }

  return ret;

}