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

 * 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/base.h>

#include <assert.h>

#include <string.h>

#include <openssl/mem.h>

#include "internal.h"

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

// kSizeTWithoutLower4Bits is a mask that can be used to zero the lower four

// bits of a |size_t|.

static const size_t kSizeTWithoutLower4Bits = (size_t) -16;

#define GCM_MUL(ctx, Xi) gcm_gmult_nohw((ctx)->Xi, (ctx)->gcm_key.Htable)

#define GHASH(ctx, in, len) \

  gcm_ghash_nohw((ctx)->Xi, (ctx)->gcm_key.Htable, in, len)

// GHASH_CHUNK is "stride parameter" missioned to mitigate cache

// trashing effect. In other words idea is to hash data while it's

// still in L1 cache after encryption pass...

#define GHASH_CHUNK (3 * 1024)

#if defined(GHASH_ASM_X86_64) || defined(GHASH_ASM_X86)

static inline void gcm_reduce_1bit(u128 *V) {

  if (sizeof(crypto_word_t) == 8) {

    uint64_t T = UINT64_C(0xe100000000000000) & (0 - (V->hi & 1));

    V->hi = (V->lo << 63) | (V->hi >> 1);

    V->lo = (V->lo >> 1) ^ T;

  } else {

    uint32_t T = 0xe1000000U & (0 - (uint32_t)(V->hi & 1));

    V->hi = (V->lo << 63) | (V->hi >> 1);

    V->lo = (V->lo >> 1) ^ ((uint64_t)T << 32);

  }

}

void gcm_init_ssse3(u128 Htable[16], const uint64_t H[2]) {

  Htable[0].hi = 0;

  Htable[0].lo = 0;

  u128 V;

  V.hi = H[1];

  V.lo = H[0];

  Htable[8] = V;

  gcm_reduce_1bit(&V);

  Htable[4] = V;

  gcm_reduce_1bit(&V);

  Htable[2] = V;

  gcm_reduce_1bit(&V);

  Htable[1] = V;

  Htable[3].hi = V.hi ^ Htable[2].hi, Htable[3].lo = V.lo ^ Htable[2].lo;

  V = Htable[4];

  Htable[5].hi = V.hi ^ Htable[1].hi, Htable[5].lo = V.lo ^ Htable[1].lo;

  Htable[6].hi = V.hi ^ Htable[2].hi, Htable[6].lo = V.lo ^ Htable[2].lo;

  Htable[7].hi = V.hi ^ Htable[3].hi, Htable[7].lo = V.lo ^ Htable[3].lo;

  V = Htable[8];

  Htable[9].hi = V.hi ^ Htable[1].hi, Htable[9].lo = V.lo ^ Htable[1].lo;

  Htable[10].hi = V.hi ^ Htable[2].hi, Htable[10].lo = V.lo ^ Htable[2].lo;

  Htable[11].hi = V.hi ^ Htable[3].hi, Htable[11].lo = V.lo ^ Htable[3].lo;

  Htable[12].hi = V.hi ^ Htable[4].hi, Htable[12].lo = V.lo ^ Htable[4].lo;

  Htable[13].hi = V.hi ^ Htable[5].hi, Htable[13].lo = V.lo ^ Htable[5].lo;

  Htable[14].hi = V.hi ^ Htable[6].hi, Htable[14].lo = V.lo ^ Htable[6].lo;

  Htable[15].hi = V.hi ^ Htable[7].hi, Htable[15].lo = V.lo ^ Htable[7].lo;

  // Treat |Htable| as a 16x16 byte table and transpose it. Thus, Htable[i]

  // contains the i'th byte of j*H for all j.

  uint8_t *Hbytes = (uint8_t *)Htable;

  for (int i = 0; i < 16; i++) {

    for (int j = 0; j < i; j++) {

      uint8_t tmp = Hbytes[16*i + j];

      Hbytes[16*i + j] = Hbytes[16*j + i];

      Hbytes[16*j + i] = tmp;

    }

  }

}

#endif  // GHASH_ASM_X86_64 || GHASH_ASM_X86

#ifdef GCM_FUNCREF

#undef GCM_MUL

#define GCM_MUL(ctx, Xi) (*gcm_gmult_p)((ctx)->Xi, (ctx)->gcm_key.Htable)

#undef GHASH

#define GHASH(ctx, in, len) \

  (*gcm_ghash_p)((ctx)->Xi, (ctx)->gcm_key.Htable, in, len)

#endif  // GCM_FUNCREF

#if defined(HW_GCM) && defined(OPENSSL_X86_64)

static size_t hw_gcm_encrypt(const uint8_t *in, uint8_t *out, size_t len,

                             const AES_KEY *key, uint8_t ivec[16],

                             uint8_t Xi[16], const u128 Htable[16]) {

  return aesni_gcm_encrypt(in, out, len, key, ivec, Htable, Xi);

}

static size_t hw_gcm_decrypt(const uint8_t *in, uint8_t *out, size_t len,

                             const AES_KEY *key, uint8_t ivec[16],

                             uint8_t Xi[16], const u128 Htable[16]) {

  return aesni_gcm_decrypt(in, out, len, key, ivec, Htable, Xi);

}

#endif  // HW_GCM && X86_64

#if defined(HW_GCM) && defined(OPENSSL_AARCH64)

static size_t hw_gcm_encrypt(const uint8_t *in, uint8_t *out, size_t len,

                             const AES_KEY *key, uint8_t ivec[16],

                             uint8_t Xi[16], const u128 Htable[16]) {

  const size_t len_blocks = len & kSizeTWithoutLower4Bits;

  if (!len_blocks) {

    return 0;

  }

  aes_gcm_enc_kernel(in, len_blocks * 8, out, Xi, ivec, key, Htable);

  return len_blocks;

}

static size_t hw_gcm_decrypt(const uint8_t *in, uint8_t *out, size_t len,

                             const AES_KEY *key, uint8_t ivec[16],

                             uint8_t Xi[16], const u128 Htable[16]) {

  const size_t len_blocks = len & kSizeTWithoutLower4Bits;

  if (!len_blocks) {

    return 0;

  }

  aes_gcm_dec_kernel(in, len_blocks * 8, out, Xi, ivec, key, Htable);

  return len_blocks;

}

#endif  // HW_GCM && AARCH64

void CRYPTO_ghash_init(gmult_func *out_mult, ghash_func *out_hash,

                       u128 out_table[16], int *out_is_avx,

                       const uint8_t gcm_key[16]) {

  *out_is_avx = 0;

  // H is passed to |gcm_init_*| as a pair of byte-swapped, 64-bit values.

  uint64_t H[2] = {CRYPTO_load_u64_be(gcm_key),

                   CRYPTO_load_u64_be(gcm_key + 8)};

#if defined(GHASH_ASM_X86_64)

  if (crypto_gcm_clmul_enabled()) {

    if (CRYPTO_is_AVX_capable() && CRYPTO_is_MOVBE_capable()) {

      gcm_init_avx(out_table, H);

      *out_mult = gcm_gmult_avx;

      *out_hash = gcm_ghash_avx;

      *out_is_avx = 1;

      return;

    }

    gcm_init_clmul(out_table, H);

    *out_mult = gcm_gmult_clmul;

    *out_hash = gcm_ghash_clmul;

    return;

  }

  if (CRYPTO_is_SSSE3_capable()) {

    gcm_init_ssse3(out_table, H);

    *out_mult = gcm_gmult_ssse3;

    *out_hash = gcm_ghash_ssse3;

    return;

  }

#elif defined(GHASH_ASM_X86)

  if (crypto_gcm_clmul_enabled()) {

    gcm_init_clmul(out_table, H);

    *out_mult = gcm_gmult_clmul;

    *out_hash = gcm_ghash_clmul;

    return;

  }

  if (CRYPTO_is_SSSE3_capable()) {

    gcm_init_ssse3(out_table, H);

    *out_mult = gcm_gmult_ssse3;

    *out_hash = gcm_ghash_ssse3;

    return;

  }

#elif defined(GHASH_ASM_ARM)

  if (gcm_pmull_capable()) {

    gcm_init_v8(out_table, H);

    *out_mult = gcm_gmult_v8;

    *out_hash = gcm_ghash_v8;

    return;

  }

  if (gcm_neon_capable()) {

    gcm_init_neon(out_table, H);

    *out_mult = gcm_gmult_neon;

    *out_hash = gcm_ghash_neon;

    return;

  }

#endif

  gcm_init_nohw(out_table, H);

  *out_mult = gcm_gmult_nohw;

  *out_hash = gcm_ghash_nohw;

}

void CRYPTO_gcm128_init_key(GCM128_KEY *gcm_key, const AES_KEY *aes_key,

                            block128_f block, int block_is_hwaes) {

  OPENSSL_memset(gcm_key, 0, sizeof(*gcm_key));

  gcm_key->block = block;

  uint8_t ghash_key[16];

  OPENSSL_memset(ghash_key, 0, sizeof(ghash_key));

  (*block)(ghash_key, ghash_key, aes_key);

  int is_avx;

  CRYPTO_ghash_init(&gcm_key->gmult, &gcm_key->ghash, gcm_key->Htable, &is_avx,

                    ghash_key);

#if defined(OPENSSL_AARCH64) && !defined(OPENSSL_NO_ASM)

  gcm_key->use_hw_gcm_crypt = (gcm_pmull_capable() && block_is_hwaes) ? 1 : 0;

#else

  gcm_key->use_hw_gcm_crypt = (is_avx && block_is_hwaes) ? 1 : 0;

#endif

}

void CRYPTO_gcm128_setiv(GCM128_CONTEXT *ctx, const AES_KEY *key,

                         const uint8_t *iv, size_t len) {

#ifdef GCM_FUNCREF

  void (*gcm_gmult_p)(uint8_t Xi[16], const u128 Htable[16]) =

      ctx->gcm_key.gmult;

#endif

  OPENSSL_memset(&ctx->Yi, 0, sizeof(ctx->Yi));

  OPENSSL_memset(&ctx->Xi, 0, sizeof(ctx->Xi));

  ctx->len.aad = 0;

  ctx->len.msg = 0;

  ctx->ares = 0;

  ctx->mres = 0;

  uint32_t ctr;

  if (len == 12) {

    OPENSSL_memcpy(ctx->Yi, iv, 12);

    ctx->Yi[15] = 1;

    ctr = 1;

  } else {

    uint64_t len0 = len;

    while (len >= 16) {

      CRYPTO_xor16(ctx->Yi, ctx->Yi, iv);

      GCM_MUL(ctx, Yi);

      iv += 16;

      len -= 16;

    }

    if (len) {

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

        ctx->Yi[i] ^= iv[i];

      }

      GCM_MUL(ctx, Yi);

    }

    uint8_t len_block[16];

    OPENSSL_memset(len_block, 0, 8);

    CRYPTO_store_u64_be(len_block + 8, len0 << 3);

    CRYPTO_xor16(ctx->Yi, ctx->Yi, len_block);

    GCM_MUL(ctx, Yi);

    ctr = CRYPTO_load_u32_be(ctx->Yi + 12);

  }

  (*ctx->gcm_key.block)(ctx->Yi, ctx->EK0, key);

  ++ctr;

  CRYPTO_store_u32_be(ctx->Yi + 12, ctr);

}

int CRYPTO_gcm128_aad(GCM128_CONTEXT *ctx, const uint8_t *aad, size_t len) {

#ifdef GCM_FUNCREF

  void (*gcm_gmult_p)(uint8_t Xi[16], const u128 Htable[16]) =

      ctx->gcm_key.gmult;

  void (*gcm_ghash_p)(uint8_t Xi[16], const u128 Htable[16], const uint8_t *inp,

                      size_t len) = ctx->gcm_key.ghash;

#endif

  if (ctx->len.msg != 0) {

    // The caller must have finished the AAD before providing other input.

    return 0;

  }

  uint64_t alen = ctx->len.aad + len;

  if (alen > (UINT64_C(1) << 61) || (sizeof(len) == 8 && alen < len)) {

    return 0;

  }

  ctx->len.aad = alen;

  unsigned n = ctx->ares;

  if (n) {

    while (n && len) {

      ctx->Xi[n] ^= *(aad++);

      --len;

      n = (n + 1) % 16;

    }

    if (n == 0) {

      GCM_MUL(ctx, Xi);

    } else {

      ctx->ares = n;

      return 1;

    }

  }

  // Process a whole number of blocks.

  size_t len_blocks = len & kSizeTWithoutLower4Bits;

  if (len_blocks != 0) {

    GHASH(ctx, aad, len_blocks);

    aad += len_blocks;

    len -= len_blocks;

  }

  // Process the remainder.

  if (len != 0) {

    n = (unsigned int)len;

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

      ctx->Xi[i] ^= aad[i];

    }

  }

  ctx->ares = n;

  return 1;

}

int CRYPTO_gcm128_encrypt(GCM128_CONTEXT *ctx, const AES_KEY *key,

                          const uint8_t *in, uint8_t *out, size_t len) {

  block128_f block = ctx->gcm_key.block;

#ifdef GCM_FUNCREF

  void (*gcm_gmult_p)(uint8_t Xi[16], const u128 Htable[16]) =

      ctx->gcm_key.gmult;

  void (*gcm_ghash_p)(uint8_t Xi[16], const u128 Htable[16], const uint8_t *inp,

                      size_t len) = ctx->gcm_key.ghash;

#endif

  uint64_t mlen = ctx->len.msg + len;

  if (mlen > ((UINT64_C(1) << 36) - 32) ||

      (sizeof(len) == 8 && mlen < len)) {

    return 0;

  }

  ctx->len.msg = mlen;

  if (ctx->ares) {

    // First call to encrypt finalizes GHASH(AAD)

    GCM_MUL(ctx, Xi);

    ctx->ares = 0;

  }

  unsigned n = ctx->mres;

  if (n) {

    while (n && len) {

      ctx->Xi[n] ^= *(out++) = *(in++) ^ ctx->EKi[n];

      --len;

      n = (n + 1) % 16;

    }

    if (n == 0) {

      GCM_MUL(ctx, Xi);

    } else {

      ctx->mres = n;

      return 1;

    }

  }

  uint32_t ctr = CRYPTO_load_u32_be(ctx->Yi + 12);

  while (len >= GHASH_CHUNK) {

    size_t j = GHASH_CHUNK;

    while (j) {

      (*block)(ctx->Yi, ctx->EKi, key);

      ++ctr;

      CRYPTO_store_u32_be(ctx->Yi + 12, ctr);

      CRYPTO_xor16(out, in, ctx->EKi);

      out += 16;

      in += 16;

      j -= 16;

    }

    GHASH(ctx, out - GHASH_CHUNK, GHASH_CHUNK);

    len -= GHASH_CHUNK;

  }

  size_t len_blocks = len & kSizeTWithoutLower4Bits;

  if (len_blocks != 0) {

    while (len >= 16) {

      (*block)(ctx->Yi, ctx->EKi, key);

      ++ctr;

      CRYPTO_store_u32_be(ctx->Yi + 12, ctr);

      CRYPTO_xor16(out, in, ctx->EKi);

      out += 16;

      in += 16;

      len -= 16;

    }

    GHASH(ctx, out - len_blocks, len_blocks);

  }

  if (len) {

    (*block)(ctx->Yi, ctx->EKi, key);

    ++ctr;

    CRYPTO_store_u32_be(ctx->Yi + 12, ctr);

    while (len--) {

      ctx->Xi[n] ^= out[n] = in[n] ^ ctx->EKi[n];

      ++n;

    }

  }

  ctx->mres = n;

  return 1;

}

int CRYPTO_gcm128_decrypt(GCM128_CONTEXT *ctx, const AES_KEY *key,

                          const unsigned char *in, unsigned char *out,

                          size_t len) {

  block128_f block = ctx->gcm_key.block;

#ifdef GCM_FUNCREF

  void (*gcm_gmult_p)(uint8_t Xi[16], const u128 Htable[16]) =

      ctx->gcm_key.gmult;

  void (*gcm_ghash_p)(uint8_t Xi[16], const u128 Htable[16], const uint8_t *inp,

                      size_t len) = ctx->gcm_key.ghash;

#endif

  uint64_t mlen = ctx->len.msg + len;

  if (mlen > ((UINT64_C(1) << 36) - 32) ||

      (sizeof(len) == 8 && mlen < len)) {

    return 0;

  }

  ctx->len.msg = mlen;

  if (ctx->ares) {

    // First call to decrypt finalizes GHASH(AAD)

    GCM_MUL(ctx, Xi);

    ctx->ares = 0;

  }

  unsigned n = ctx->mres;

  if (n) {

    while (n && len) {

      uint8_t c = *(in++);

      *(out++) = c ^ ctx->EKi[n];

      ctx->Xi[n] ^= c;

      --len;

      n = (n + 1) % 16;

    }

    if (n == 0) {

      GCM_MUL(ctx, Xi);

    } else {

      ctx->mres = n;

      return 1;

    }

  }

  uint32_t ctr = CRYPTO_load_u32_be(ctx->Yi + 12);

  while (len >= GHASH_CHUNK) {

    size_t j = GHASH_CHUNK;

    GHASH(ctx, in, GHASH_CHUNK);

    while (j) {

      (*block)(ctx->Yi, ctx->EKi, key);

      ++ctr;

      CRYPTO_store_u32_be(ctx->Yi + 12, ctr);

      CRYPTO_xor16(out, in, ctx->EKi);

      out += 16;

      in += 16;

      j -= 16;

    }

    len -= GHASH_CHUNK;

  }

  size_t len_blocks = len & kSizeTWithoutLower4Bits;

  if (len_blocks != 0) {

    GHASH(ctx, in, len_blocks);

    while (len >= 16) {

      (*block)(ctx->Yi, ctx->EKi, key);

      ++ctr;

      CRYPTO_store_u32_be(ctx->Yi + 12, ctr);

      CRYPTO_xor16(out, in, ctx->EKi);

      out += 16;

      in += 16;

      len -= 16;

    }

  }

  if (len) {

    (*block)(ctx->Yi, ctx->EKi, key);

    ++ctr;

    CRYPTO_store_u32_be(ctx->Yi + 12, ctr);

    while (len--) {

      uint8_t c = in[n];

      ctx->Xi[n] ^= c;

      out[n] = c ^ ctx->EKi[n];

      ++n;

    }

  }

  ctx->mres = n;

  return 1;

}

int CRYPTO_gcm128_encrypt_ctr32(GCM128_CONTEXT *ctx, const AES_KEY *key,

                                const uint8_t *in, uint8_t *out, size_t len,

                                ctr128_f stream) {

#ifdef GCM_FUNCREF

  void (*gcm_gmult_p)(uint8_t Xi[16], const u128 Htable[16]) =

      ctx->gcm_key.gmult;

  void (*gcm_ghash_p)(uint8_t Xi[16], const u128 Htable[16], const uint8_t *inp,

                      size_t len) = ctx->gcm_key.ghash;

#endif

  uint64_t mlen = ctx->len.msg + len;

  if (mlen > ((UINT64_C(1) << 36) - 32) ||

      (sizeof(len) == 8 && mlen < len)) {

    return 0;

  }

  ctx->len.msg = mlen;

  if (ctx->ares) {

    // First call to encrypt finalizes GHASH(AAD)

    GCM_MUL(ctx, Xi);

    ctx->ares = 0;

  }

  unsigned n = ctx->mres;

  if (n) {

    while (n && len) {

      ctx->Xi[n] ^= *(out++) = *(in++) ^ ctx->EKi[n];

      --len;

      n = (n + 1) % 16;

    }

    if (n == 0) {

      GCM_MUL(ctx, Xi);

    } else {

      ctx->mres = n;

      return 1;

    }

  }

#if defined(HW_GCM)

  // Check |len| to work around a C language bug. See https://crbug.com/1019588.

  if (ctx->gcm_key.use_hw_gcm_crypt && len > 0) {

    // |hw_gcm_encrypt| may not process all the input given to it. It may

    // not process *any* of its input if it is deemed too small.

    size_t bulk = hw_gcm_encrypt(in, out, len, key, ctx->Yi, ctx->Xi,

                                 ctx->gcm_key.Htable);

    in += bulk;

    out += bulk;

    len -= bulk;

  }

#endif

  uint32_t ctr = CRYPTO_load_u32_be(ctx->Yi + 12);

  while (len >= GHASH_CHUNK) {

    (*stream)(in, out, GHASH_CHUNK / 16, key, ctx->Yi);

    ctr += GHASH_CHUNK / 16;

    CRYPTO_store_u32_be(ctx->Yi + 12, ctr);

    GHASH(ctx, out, GHASH_CHUNK);

    out += GHASH_CHUNK;

    in += GHASH_CHUNK;

    len -= GHASH_CHUNK;

  }

  size_t len_blocks = len & kSizeTWithoutLower4Bits;

  if (len_blocks != 0) {

    size_t j = len_blocks / 16;

    (*stream)(in, out, j, key, ctx->Yi);

    ctr += (unsigned int)j;

    CRYPTO_store_u32_be(ctx->Yi + 12, ctr);

    in += len_blocks;

    len -= len_blocks;

    GHASH(ctx, out, len_blocks);

    out += len_blocks;

  }

  if (len) {

    (*ctx->gcm_key.block)(ctx->Yi, ctx->EKi, key);

    ++ctr;

    CRYPTO_store_u32_be(ctx->Yi + 12, ctr);

    while (len--) {

      ctx->Xi[n] ^= out[n] = in[n] ^ ctx->EKi[n];

      ++n;

    }

  }

  ctx->mres = n;

  return 1;

}

int CRYPTO_gcm128_decrypt_ctr32(GCM128_CONTEXT *ctx, const AES_KEY *key,

                                const uint8_t *in, uint8_t *out, size_t len,

                                ctr128_f stream) {

#ifdef GCM_FUNCREF

  void (*gcm_gmult_p)(uint8_t Xi[16], const u128 Htable[16]) =

      ctx->gcm_key.gmult;

  void (*gcm_ghash_p)(uint8_t Xi[16], const u128 Htable[16], const uint8_t *inp,

                      size_t len) = ctx->gcm_key.ghash;

#endif

  uint64_t mlen = ctx->len.msg + len;

  if (mlen > ((UINT64_C(1) << 36) - 32) ||

      (sizeof(len) == 8 && mlen < len)) {

    return 0;

  }

  ctx->len.msg = mlen;

  if (ctx->ares) {

    // First call to decrypt finalizes GHASH(AAD)

    GCM_MUL(ctx, Xi);

    ctx->ares = 0;

  }

  unsigned n = ctx->mres;

  if (n) {

    while (n && len) {

      uint8_t c = *(in++);

      *(out++) = c ^ ctx->EKi[n];

      ctx->Xi[n] ^= c;

      --len;

      n = (n + 1) % 16;

    }

    if (n == 0) {

      GCM_MUL(ctx, Xi);

    } else {

      ctx->mres = n;

      return 1;

    }

  }

#if defined(HW_GCM)

  // Check |len| to work around a C language bug. See https://crbug.com/1019588.

  if (ctx->gcm_key.use_hw_gcm_crypt && len > 0) {

    // |hw_gcm_decrypt| may not process all the input given to it. It may

    // not process *any* of its input if it is deemed too small.

    size_t bulk = hw_gcm_decrypt(in, out, len, key, ctx->Yi, ctx->Xi,

                                 ctx->gcm_key.Htable);

    in += bulk;

    out += bulk;

    len -= bulk;

  }

#endif

  uint32_t ctr = CRYPTO_load_u32_be(ctx->Yi + 12);

  while (len >= GHASH_CHUNK) {

    GHASH(ctx, in, GHASH_CHUNK);

    (*stream)(in, out, GHASH_CHUNK / 16, key, ctx->Yi);

    ctr += GHASH_CHUNK / 16;

    CRYPTO_store_u32_be(ctx->Yi + 12, ctr);

    out += GHASH_CHUNK;

    in += GHASH_CHUNK;

    len -= GHASH_CHUNK;

  }

  size_t len_blocks = len & kSizeTWithoutLower4Bits;

  if (len_blocks != 0) {

    size_t j = len_blocks / 16;

    GHASH(ctx, in, len_blocks);

    (*stream)(in, out, j, key, ctx->Yi);

    ctr += (unsigned int)j;

    CRYPTO_store_u32_be(ctx->Yi + 12, ctr);

    out += len_blocks;

    in += len_blocks;

    len -= len_blocks;

  }

  if (len) {

    (*ctx->gcm_key.block)(ctx->Yi, ctx->EKi, key);

    ++ctr;

    CRYPTO_store_u32_be(ctx->Yi + 12, ctr);

    while (len--) {

      uint8_t c = in[n];

      ctx->Xi[n] ^= c;

      out[n] = c ^ ctx->EKi[n];

      ++n;

    }

  }

  ctx->mres = n;

  return 1;

}

int CRYPTO_gcm128_finish(GCM128_CONTEXT *ctx, const uint8_t *tag, size_t len) {

#ifdef GCM_FUNCREF

  void (*gcm_gmult_p)(uint8_t Xi[16], const u128 Htable[16]) =

      ctx->gcm_key.gmult;

#endif

  if (ctx->mres || ctx->ares) {

    GCM_MUL(ctx, Xi);

  }

  uint8_t len_block[16];

  CRYPTO_store_u64_be(len_block, ctx->len.aad << 3);

  CRYPTO_store_u64_be(len_block + 8, ctx->len.msg << 3);

  CRYPTO_xor16(ctx->Xi, ctx->Xi, len_block);

  GCM_MUL(ctx, Xi);

  CRYPTO_xor16(ctx->Xi, ctx->Xi, ctx->EK0);

  if (tag && len <= sizeof(ctx->Xi)) {

    return CRYPTO_memcmp(ctx->Xi, tag, len) == 0;

  } else {

    return 0;

  }

}

void CRYPTO_gcm128_tag(GCM128_CONTEXT *ctx, unsigned char *tag, size_t len) {

  CRYPTO_gcm128_finish(ctx, NULL, 0);

  OPENSSL_memcpy(tag, ctx->Xi, len <= sizeof(ctx->Xi) ? len : sizeof(ctx->Xi));

}

#if defined(OPENSSL_X86) || defined(OPENSSL_X86_64)

int crypto_gcm_clmul_enabled(void) {

#if defined(GHASH_ASM_X86) || defined(GHASH_ASM_X86_64)

  return CRYPTO_is_FXSR_capable() && CRYPTO_is_PCLMUL_capable();

#else

  return 0;

#endif

}

#endif