crypto/fipsmodule/modes/gcm.c - boringssl - Git at Google

 /* ====================================================================
  * 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.u, (ctx)->gcm_key.Htable)
 #define GHASH(ctx, in, len) \
   gcm_ghash_nohw((ctx)->Xi.u, (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.u, (ctx)->gcm_key.Htable)
 #undef GHASH
 #define GHASH(ctx, in, len) \
   (*gcm_ghash_p)((ctx)->Xi.u, (ctx)->gcm_key.Htable, in, len)
 #endif  // GCM_FUNCREF

 void CRYPTO_ghash_init(gmult_func *out_mult, ghash_func *out_hash,
                        u128 *out_key, u128 out_table[16], int *out_is_avx,
                        const uint8_t gcm_key[16]) {
   *out_is_avx = 0;

   union {
     uint64_t u[2];
     uint8_t c[16];
   } H;

   OPENSSL_memcpy(H.c, gcm_key, 16);

   // H is stored in host byte order
   H.u[0] = CRYPTO_bswap8(H.u[0]);
   H.u[1] = CRYPTO_bswap8(H.u[1]);

   OPENSSL_memcpy(out_key, H.c, 16);

 #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.u);
       *out_mult = gcm_gmult_avx;
       *out_hash = gcm_ghash_avx;
       *out_is_avx = 1;
       return;
     }
     gcm_init_clmul(out_table, H.u);
     *out_mult = gcm_gmult_clmul;
     *out_hash = gcm_ghash_clmul;
     return;
   }
   if (CRYPTO_is_SSSE3_capable()) {
     gcm_init_ssse3(out_table, H.u);
     *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.u);
     *out_mult = gcm_gmult_clmul;
     *out_hash = gcm_ghash_clmul;
     return;
   }
   if (CRYPTO_is_SSSE3_capable()) {
     gcm_init_ssse3(out_table, H.u);
     *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.u);
     *out_mult = gcm_gmult_v8;
     *out_hash = gcm_ghash_v8;
     return;
   }

   if (gcm_neon_capable()) {
     gcm_init_neon(out_table, H.u);
     *out_mult = gcm_gmult_neon;
     *out_hash = gcm_ghash_neon;
     return;
   }
 #elif defined(GHASH_ASM_PPC64LE)
   if (CRYPTO_is_PPC64LE_vcrypto_capable()) {
     gcm_init_p8(out_table, H.u);
     *out_mult = gcm_gmult_p8;
     *out_hash = gcm_ghash_p8;
     return;
   }
 #endif

   gcm_init_nohw(out_table, H.u);
   *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->H,
                     gcm_key->Htable, &is_avx, ghash_key);

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

 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)(uint64_t Xi[2], const u128 Htable[16]) =
       ctx->gcm_key.gmult;
 #endif

   ctx->Yi.u[0] = 0;
   ctx->Yi.u[1] = 0;
   ctx->Xi.u[0] = 0;
   ctx->Xi.u[1] = 0;
   ctx->len.u[0] = 0;  // AAD length
   ctx->len.u[1] = 0;  // message length
   ctx->ares = 0;
   ctx->mres = 0;

   uint32_t ctr;
   if (len == 12) {
     OPENSSL_memcpy(ctx->Yi.c, iv, 12);
     ctx->Yi.c[15] = 1;
     ctr = 1;
   } else {
     uint64_t len0 = len;

     while (len >= 16) {
       for (size_t i = 0; i < 16; ++i) {
         ctx->Yi.c[i] ^= iv[i];
       }
       GCM_MUL(ctx, Yi);
       iv += 16;
       len -= 16;
     }
     if (len) {
       for (size_t i = 0; i < len; ++i) {
         ctx->Yi.c[i] ^= iv[i];
       }
       GCM_MUL(ctx, Yi);
     }
     len0 <<= 3;
     ctx->Yi.u[1] ^= CRYPTO_bswap8(len0);

     GCM_MUL(ctx, Yi);
     ctr = CRYPTO_bswap4(ctx->Yi.d[3]);
   }

   (*ctx->gcm_key.block)(ctx->Yi.c, ctx->EK0.c, key);
   ++ctr;
   ctx->Yi.d[3] = CRYPTO_bswap4(ctr);
 }

 int CRYPTO_gcm128_aad(GCM128_CONTEXT *ctx, const uint8_t *aad, size_t len) {
 #ifdef GCM_FUNCREF
   void (*gcm_gmult_p)(uint64_t Xi[2], const u128 Htable[16]) =
       ctx->gcm_key.gmult;
   void (*gcm_ghash_p)(uint64_t Xi[2], const u128 Htable[16], const uint8_t *inp,
                       size_t len) = ctx->gcm_key.ghash;
 #endif

   if (ctx->len.u[1]) {
     return 0;
   }

   uint64_t alen = ctx->len.u[0] + len;
   if (alen > (UINT64_C(1) << 61) || (sizeof(len) == 8 && alen < len)) {
     return 0;
   }
   ctx->len.u[0] = alen;

   unsigned n = ctx->ares;
   if (n) {
     while (n && len) {
       ctx->Xi.c[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.c[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)(uint64_t Xi[2], const u128 Htable[16]) =
       ctx->gcm_key.gmult;
   void (*gcm_ghash_p)(uint64_t Xi[2], const u128 Htable[16], const uint8_t *inp,
                       size_t len) = ctx->gcm_key.ghash;
 #endif

   uint64_t mlen = ctx->len.u[1] + len;
   if (mlen > ((UINT64_C(1) << 36) - 32) ||
       (sizeof(len) == 8 && mlen < len)) {
     return 0;
   }
   ctx->len.u[1] = 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.c[n] ^= *(out++) = *(in++) ^ ctx->EKi.c[n];
       --len;
       n = (n + 1) % 16;
     }
     if (n == 0) {
       GCM_MUL(ctx, Xi);
     } else {
       ctx->mres = n;
       return 1;
     }
   }

   uint32_t ctr = CRYPTO_bswap4(ctx->Yi.d[3]);
   while (len >= GHASH_CHUNK) {
     size_t j = GHASH_CHUNK;

     while (j) {
       (*block)(ctx->Yi.c, ctx->EKi.c, key);
       ++ctr;
       ctx->Yi.d[3] = CRYPTO_bswap4(ctr);
       for (size_t i = 0; i < 16; i += sizeof(crypto_word_t)) {
         CRYPTO_store_word_le(out + i,
                              CRYPTO_load_word_le(in + i) ^
                                  ctx->EKi.t[i / sizeof(crypto_word_t)]);
       }
       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.c, ctx->EKi.c, key);
       ++ctr;
       ctx->Yi.d[3] = CRYPTO_bswap4(ctr);
       for (size_t i = 0; i < 16; i += sizeof(crypto_word_t)) {
         CRYPTO_store_word_le(out + i,
                              CRYPTO_load_word_le(in + i) ^
                                  ctx->EKi.t[i / sizeof(crypto_word_t)]);
       }
       out += 16;
       in += 16;
       len -= 16;
     }
     GHASH(ctx, out - len_blocks, len_blocks);
   }
   if (len) {
     (*block)(ctx->Yi.c, ctx->EKi.c, key);
     ++ctr;
     ctx->Yi.d[3] = CRYPTO_bswap4(ctr);
     while (len--) {
       ctx->Xi.c[n] ^= out[n] = in[n] ^ ctx->EKi.c[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)(uint64_t Xi[2], const u128 Htable[16]) =
       ctx->gcm_key.gmult;
   void (*gcm_ghash_p)(uint64_t Xi[2], const u128 Htable[16], const uint8_t *inp,
                       size_t len) = ctx->gcm_key.ghash;
 #endif

   uint64_t mlen = ctx->len.u[1] + len;
   if (mlen > ((UINT64_C(1) << 36) - 32) ||
       (sizeof(len) == 8 && mlen < len)) {
     return 0;
   }
   ctx->len.u[1] = 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.c[n];
       ctx->Xi.c[n] ^= c;
       --len;
       n = (n + 1) % 16;
     }
     if (n == 0) {
       GCM_MUL(ctx, Xi);
     } else {
       ctx->mres = n;
       return 1;
     }
   }

   uint32_t ctr = CRYPTO_bswap4(ctx->Yi.d[3]);
   while (len >= GHASH_CHUNK) {
     size_t j = GHASH_CHUNK;

     GHASH(ctx, in, GHASH_CHUNK);
     while (j) {
       (*block)(ctx->Yi.c, ctx->EKi.c, key);
       ++ctr;
       ctx->Yi.d[3] = CRYPTO_bswap4(ctr);
       for (size_t i = 0; i < 16; i += sizeof(crypto_word_t)) {
         CRYPTO_store_word_le(out + i,
                              CRYPTO_load_word_le(in + i) ^
                                  ctx->EKi.t[i / sizeof(crypto_word_t)]);
       }
       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.c, ctx->EKi.c, key);
       ++ctr;
       ctx->Yi.d[3] = CRYPTO_bswap4(ctr);
       for (size_t i = 0; i < 16; i += sizeof(crypto_word_t)) {
         CRYPTO_store_word_le(out + i,
                              CRYPTO_load_word_le(in + i) ^
                                  ctx->EKi.t[i / sizeof(crypto_word_t)]);
       }
       out += 16;
       in += 16;
       len -= 16;
     }
   }
   if (len) {
     (*block)(ctx->Yi.c, ctx->EKi.c, key);
     ++ctr;
     ctx->Yi.d[3] = CRYPTO_bswap4(ctr);
     while (len--) {
       uint8_t c = in[n];
       ctx->Xi.c[n] ^= c;
       out[n] = c ^ ctx->EKi.c[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)(uint64_t Xi[2], const u128 Htable[16]) =
       ctx->gcm_key.gmult;
   void (*gcm_ghash_p)(uint64_t Xi[2], const u128 Htable[16], const uint8_t *inp,
                       size_t len) = ctx->gcm_key.ghash;
 #endif

   uint64_t mlen = ctx->len.u[1] + len;
   if (mlen > ((UINT64_C(1) << 36) - 32) ||
       (sizeof(len) == 8 && mlen < len)) {
     return 0;
   }
   ctx->len.u[1] = 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.c[n] ^= *(out++) = *(in++) ^ ctx->EKi.c[n];
       --len;
       n = (n + 1) % 16;
     }
     if (n == 0) {
       GCM_MUL(ctx, Xi);
     } else {
       ctx->mres = n;
       return 1;
     }
   }

 #if defined(AESNI_GCM)
   // Check |len| to work around a C language bug. See https://crbug.com/1019588.
   if (ctx->gcm_key.use_aesni_gcm_crypt && len > 0) {
     // |aesni_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 = aesni_gcm_encrypt(in, out, len, key, ctx->Yi.c, ctx->Xi.u);
     in += bulk;
     out += bulk;
     len -= bulk;
   }
 #endif

   uint32_t ctr = CRYPTO_bswap4(ctx->Yi.d[3]);
   while (len >= GHASH_CHUNK) {
     (*stream)(in, out, GHASH_CHUNK / 16, key, ctx->Yi.c);
     ctr += GHASH_CHUNK / 16;
     ctx->Yi.d[3] = CRYPTO_bswap4(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.c);
     ctr += (unsigned int)j;
     ctx->Yi.d[3] = CRYPTO_bswap4(ctr);
     in += len_blocks;
     len -= len_blocks;
     GHASH(ctx, out, len_blocks);
     out += len_blocks;
   }
   if (len) {
     (*ctx->gcm_key.block)(ctx->Yi.c, ctx->EKi.c, key);
     ++ctr;
     ctx->Yi.d[3] = CRYPTO_bswap4(ctr);
     while (len--) {
       ctx->Xi.c[n] ^= out[n] = in[n] ^ ctx->EKi.c[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)(uint64_t Xi[2], const u128 Htable[16]) =
       ctx->gcm_key.gmult;
   void (*gcm_ghash_p)(uint64_t Xi[2], const u128 Htable[16], const uint8_t *inp,
                       size_t len) = ctx->gcm_key.ghash;
 #endif

   uint64_t mlen = ctx->len.u[1] + len;
   if (mlen > ((UINT64_C(1) << 36) - 32) ||
       (sizeof(len) == 8 && mlen < len)) {
     return 0;
   }
   ctx->len.u[1] = 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.c[n];
       ctx->Xi.c[n] ^= c;
       --len;
       n = (n + 1) % 16;
     }
     if (n == 0) {
       GCM_MUL(ctx, Xi);
     } else {
       ctx->mres = n;
       return 1;
     }
   }

 #if defined(AESNI_GCM)
   // Check |len| to work around a C language bug. See https://crbug.com/1019588.
   if (ctx->gcm_key.use_aesni_gcm_crypt && len > 0) {
     // |aesni_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 = aesni_gcm_decrypt(in, out, len, key, ctx->Yi.c, ctx->Xi.u);
     in += bulk;
     out += bulk;
     len -= bulk;
   }
 #endif

   uint32_t ctr = CRYPTO_bswap4(ctx->Yi.d[3]);
   while (len >= GHASH_CHUNK) {
     GHASH(ctx, in, GHASH_CHUNK);
     (*stream)(in, out, GHASH_CHUNK / 16, key, ctx->Yi.c);
     ctr += GHASH_CHUNK / 16;
     ctx->Yi.d[3] = CRYPTO_bswap4(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.c);
     ctr += (unsigned int)j;
     ctx->Yi.d[3] = CRYPTO_bswap4(ctr);
     out += len_blocks;
     in += len_blocks;
     len -= len_blocks;
   }
   if (len) {
     (*ctx->gcm_key.block)(ctx->Yi.c, ctx->EKi.c, key);
     ++ctr;
     ctx->Yi.d[3] = CRYPTO_bswap4(ctr);
     while (len--) {
       uint8_t c = in[n];
       ctx->Xi.c[n] ^= c;
       out[n] = c ^ ctx->EKi.c[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)(uint64_t Xi[2], const u128 Htable[16]) =
       ctx->gcm_key.gmult;
 #endif

   if (ctx->mres || ctx->ares) {
     GCM_MUL(ctx, Xi);
   }

   ctx->Xi.u[0] ^= CRYPTO_bswap8(ctx->len.u[0] << 3);
   ctx->Xi.u[1] ^= CRYPTO_bswap8(ctx->len.u[1] << 3);
   GCM_MUL(ctx, Xi);

   ctx->Xi.u[0] ^= ctx->EK0.u[0];
   ctx->Xi.u[1] ^= ctx->EK0.u[1];

   if (tag && len <= sizeof(ctx->Xi)) {
     return CRYPTO_memcmp(ctx->Xi.c, 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.c,
                  len <= sizeof(ctx->Xi.c) ? len : sizeof(ctx->Xi.c));
 }

 #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
	/* ====================================================================
	* 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.u, (ctx)->gcm_key.Htable)
	#define GHASH(ctx, in, len) \
	gcm_ghash_nohw((ctx)->Xi.u, (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[16i + j] = Hbytes[16j + 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.u, (ctx)->gcm_key.Htable)
	#undef GHASH
	#define GHASH(ctx, in, len) \
	(*gcm_ghash_p)((ctx)->Xi.u, (ctx)->gcm_key.Htable, in, len)
	#endif // GCM_FUNCREF

	void CRYPTO_ghash_init(gmult_func out_mult, ghash_func out_hash,
	u128 out_key, u128 out_table[16], int out_is_avx,
	const uint8_t gcm_key[16]) {
	*out_is_avx = 0;

	union {
	uint64_t u[2];
	uint8_t c[16];
	} H;

	OPENSSL_memcpy(H.c, gcm_key, 16);

	// H is stored in host byte order
	H.u[0] = CRYPTO_bswap8(H.u[0]);
	H.u[1] = CRYPTO_bswap8(H.u[1]);

	OPENSSL_memcpy(out_key, H.c, 16);

	#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.u);
	*out_mult = gcm_gmult_avx;
	*out_hash = gcm_ghash_avx;
	*out_is_avx = 1;
	return;
	}
	gcm_init_clmul(out_table, H.u);
	*out_mult = gcm_gmult_clmul;
	*out_hash = gcm_ghash_clmul;
	return;
	}
	if (CRYPTO_is_SSSE3_capable()) {
	gcm_init_ssse3(out_table, H.u);
	*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.u);
	*out_mult = gcm_gmult_clmul;
	*out_hash = gcm_ghash_clmul;
	return;
	}
	if (CRYPTO_is_SSSE3_capable()) {
	gcm_init_ssse3(out_table, H.u);
	*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.u);
	*out_mult = gcm_gmult_v8;
	*out_hash = gcm_ghash_v8;
	return;
	}

	if (gcm_neon_capable()) {
	gcm_init_neon(out_table, H.u);
	*out_mult = gcm_gmult_neon;
	*out_hash = gcm_ghash_neon;
	return;
	}
	#elif defined(GHASH_ASM_PPC64LE)
	if (CRYPTO_is_PPC64LE_vcrypto_capable()) {
	gcm_init_p8(out_table, H.u);
	*out_mult = gcm_gmult_p8;
	*out_hash = gcm_ghash_p8;
	return;
	}
	#endif

	gcm_init_nohw(out_table, H.u);
	*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->H,
	gcm_key->Htable, &is_avx, ghash_key);

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

	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)(uint64_t Xi[2], const u128 Htable[16]) =
	ctx->gcm_key.gmult;
	#endif

	ctx->Yi.u[0] = 0;
	ctx->Yi.u[1] = 0;
	ctx->Xi.u[0] = 0;
	ctx->Xi.u[1] = 0;
	ctx->len.u[0] = 0; // AAD length
	ctx->len.u[1] = 0; // message length
	ctx->ares = 0;
	ctx->mres = 0;

	uint32_t ctr;
	if (len == 12) {
	OPENSSL_memcpy(ctx->Yi.c, iv, 12);
	ctx->Yi.c[15] = 1;
	ctr = 1;
	} else {
	uint64_t len0 = len;

	while (len >= 16) {
	for (size_t i = 0; i < 16; ++i) {
	ctx->Yi.c[i] ^= iv[i];
	}
	GCM_MUL(ctx, Yi);
	iv += 16;
	len -= 16;
	}
	if (len) {
	for (size_t i = 0; i < len; ++i) {
	ctx->Yi.c[i] ^= iv[i];
	}
	GCM_MUL(ctx, Yi);
	}
	len0 <<= 3;
	ctx->Yi.u[1] ^= CRYPTO_bswap8(len0);

	GCM_MUL(ctx, Yi);
	ctr = CRYPTO_bswap4(ctx->Yi.d[3]);
	}

	(*ctx->gcm_key.block)(ctx->Yi.c, ctx->EK0.c, key);
	++ctr;
	ctx->Yi.d[3] = CRYPTO_bswap4(ctr);
	}

	int CRYPTO_gcm128_aad(GCM128_CONTEXT ctx, const uint8_t aad, size_t len) {
	#ifdef GCM_FUNCREF
	void (*gcm_gmult_p)(uint64_t Xi[2], const u128 Htable[16]) =
	ctx->gcm_key.gmult;
	void (gcm_ghash_p)(uint64_t Xi[2], const u128 Htable[16], const uint8_t inp,
	size_t len) = ctx->gcm_key.ghash;
	#endif

	if (ctx->len.u[1]) {
	return 0;
	}

	uint64_t alen = ctx->len.u[0] + len;
	if (alen > (UINT64_C(1) << 61) \|\| (sizeof(len) == 8 && alen < len)) {
	return 0;
	}
	ctx->len.u[0] = alen;

	unsigned n = ctx->ares;
	if (n) {
	while (n && len) {
	ctx->Xi.c[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.c[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)(uint64_t Xi[2], const u128 Htable[16]) =
	ctx->gcm_key.gmult;
	void (gcm_ghash_p)(uint64_t Xi[2], const u128 Htable[16], const uint8_t inp,
	size_t len) = ctx->gcm_key.ghash;
	#endif

	uint64_t mlen = ctx->len.u[1] + len;
	if (mlen > ((UINT64_C(1) << 36) - 32) \|\|
	(sizeof(len) == 8 && mlen < len)) {
	return 0;
	}
	ctx->len.u[1] = 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.c[n] ^= (out++) = (in++) ^ ctx->EKi.c[n];
	--len;
	n = (n + 1) % 16;
	}
	if (n == 0) {
	GCM_MUL(ctx, Xi);
	} else {
	ctx->mres = n;
	return 1;
	}
	}

	uint32_t ctr = CRYPTO_bswap4(ctx->Yi.d[3]);
	while (len >= GHASH_CHUNK) {
	size_t j = GHASH_CHUNK;

	while (j) {
	(*block)(ctx->Yi.c, ctx->EKi.c, key);
	++ctr;
	ctx->Yi.d[3] = CRYPTO_bswap4(ctr);
	for (size_t i = 0; i < 16; i += sizeof(crypto_word_t)) {
	CRYPTO_store_word_le(out + i,
	CRYPTO_load_word_le(in + i) ^
	ctx->EKi.t[i / sizeof(crypto_word_t)]);
	}
	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.c, ctx->EKi.c, key);
	++ctr;
	ctx->Yi.d[3] = CRYPTO_bswap4(ctr);
	for (size_t i = 0; i < 16; i += sizeof(crypto_word_t)) {
	CRYPTO_store_word_le(out + i,
	CRYPTO_load_word_le(in + i) ^
	ctx->EKi.t[i / sizeof(crypto_word_t)]);
	}
	out += 16;
	in += 16;
	len -= 16;
	}
	GHASH(ctx, out - len_blocks, len_blocks);
	}
	if (len) {
	(*block)(ctx->Yi.c, ctx->EKi.c, key);
	++ctr;
	ctx->Yi.d[3] = CRYPTO_bswap4(ctr);
	while (len--) {
	ctx->Xi.c[n] ^= out[n] = in[n] ^ ctx->EKi.c[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)(uint64_t Xi[2], const u128 Htable[16]) =
	ctx->gcm_key.gmult;
	void (gcm_ghash_p)(uint64_t Xi[2], const u128 Htable[16], const uint8_t inp,
	size_t len) = ctx->gcm_key.ghash;
	#endif

	uint64_t mlen = ctx->len.u[1] + len;
	if (mlen > ((UINT64_C(1) << 36) - 32) \|\|
	(sizeof(len) == 8 && mlen < len)) {
	return 0;
	}
	ctx->len.u[1] = 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.c[n];
	ctx->Xi.c[n] ^= c;
	--len;
	n = (n + 1) % 16;
	}
	if (n == 0) {
	GCM_MUL(ctx, Xi);
	} else {
	ctx->mres = n;
	return 1;
	}
	}

	uint32_t ctr = CRYPTO_bswap4(ctx->Yi.d[3]);
	while (len >= GHASH_CHUNK) {
	size_t j = GHASH_CHUNK;

	GHASH(ctx, in, GHASH_CHUNK);
	while (j) {
	(*block)(ctx->Yi.c, ctx->EKi.c, key);
	++ctr;
	ctx->Yi.d[3] = CRYPTO_bswap4(ctr);
	for (size_t i = 0; i < 16; i += sizeof(crypto_word_t)) {
	CRYPTO_store_word_le(out + i,
	CRYPTO_load_word_le(in + i) ^
	ctx->EKi.t[i / sizeof(crypto_word_t)]);
	}
	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.c, ctx->EKi.c, key);
	++ctr;
	ctx->Yi.d[3] = CRYPTO_bswap4(ctr);
	for (size_t i = 0; i < 16; i += sizeof(crypto_word_t)) {
	CRYPTO_store_word_le(out + i,
	CRYPTO_load_word_le(in + i) ^
	ctx->EKi.t[i / sizeof(crypto_word_t)]);
	}
	out += 16;
	in += 16;
	len -= 16;
	}
	}
	if (len) {
	(*block)(ctx->Yi.c, ctx->EKi.c, key);
	++ctr;
	ctx->Yi.d[3] = CRYPTO_bswap4(ctr);
	while (len--) {
	uint8_t c = in[n];
	ctx->Xi.c[n] ^= c;
	out[n] = c ^ ctx->EKi.c[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)(uint64_t Xi[2], const u128 Htable[16]) =
	ctx->gcm_key.gmult;
	void (gcm_ghash_p)(uint64_t Xi[2], const u128 Htable[16], const uint8_t inp,
	size_t len) = ctx->gcm_key.ghash;
	#endif

	uint64_t mlen = ctx->len.u[1] + len;
	if (mlen > ((UINT64_C(1) << 36) - 32) \|\|
	(sizeof(len) == 8 && mlen < len)) {
	return 0;
	}
	ctx->len.u[1] = 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.c[n] ^= (out++) = (in++) ^ ctx->EKi.c[n];
	--len;
	n = (n + 1) % 16;
	}
	if (n == 0) {
	GCM_MUL(ctx, Xi);
	} else {
	ctx->mres = n;
	return 1;
	}
	}

	#if defined(AESNI_GCM)
	// Check \|len\| to work around a C language bug. See https://crbug.com/1019588.
	if (ctx->gcm_key.use_aesni_gcm_crypt && len > 0) {
	// \|aesni_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 = aesni_gcm_encrypt(in, out, len, key, ctx->Yi.c, ctx->Xi.u);
	in += bulk;
	out += bulk;
	len -= bulk;
	}
	#endif

	uint32_t ctr = CRYPTO_bswap4(ctx->Yi.d[3]);
	while (len >= GHASH_CHUNK) {
	(*stream)(in, out, GHASH_CHUNK / 16, key, ctx->Yi.c);
	ctr += GHASH_CHUNK / 16;
	ctx->Yi.d[3] = CRYPTO_bswap4(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.c);
	ctr += (unsigned int)j;
	ctx->Yi.d[3] = CRYPTO_bswap4(ctr);
	in += len_blocks;
	len -= len_blocks;
	GHASH(ctx, out, len_blocks);
	out += len_blocks;
	}
	if (len) {
	(*ctx->gcm_key.block)(ctx->Yi.c, ctx->EKi.c, key);
	++ctr;
	ctx->Yi.d[3] = CRYPTO_bswap4(ctr);
	while (len--) {
	ctx->Xi.c[n] ^= out[n] = in[n] ^ ctx->EKi.c[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)(uint64_t Xi[2], const u128 Htable[16]) =
	ctx->gcm_key.gmult;
	void (gcm_ghash_p)(uint64_t Xi[2], const u128 Htable[16], const uint8_t inp,
	size_t len) = ctx->gcm_key.ghash;
	#endif

	uint64_t mlen = ctx->len.u[1] + len;
	if (mlen > ((UINT64_C(1) << 36) - 32) \|\|
	(sizeof(len) == 8 && mlen < len)) {
	return 0;
	}
	ctx->len.u[1] = 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.c[n];
	ctx->Xi.c[n] ^= c;
	--len;
	n = (n + 1) % 16;
	}
	if (n == 0) {
	GCM_MUL(ctx, Xi);
	} else {
	ctx->mres = n;
	return 1;
	}
	}

	#if defined(AESNI_GCM)
	// Check \|len\| to work around a C language bug. See https://crbug.com/1019588.
	if (ctx->gcm_key.use_aesni_gcm_crypt && len > 0) {
	// \|aesni_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 = aesni_gcm_decrypt(in, out, len, key, ctx->Yi.c, ctx->Xi.u);
	in += bulk;
	out += bulk;
	len -= bulk;
	}
	#endif

	uint32_t ctr = CRYPTO_bswap4(ctx->Yi.d[3]);
	while (len >= GHASH_CHUNK) {
	GHASH(ctx, in, GHASH_CHUNK);
	(*stream)(in, out, GHASH_CHUNK / 16, key, ctx->Yi.c);
	ctr += GHASH_CHUNK / 16;
	ctx->Yi.d[3] = CRYPTO_bswap4(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.c);
	ctr += (unsigned int)j;
	ctx->Yi.d[3] = CRYPTO_bswap4(ctr);
	out += len_blocks;
	in += len_blocks;
	len -= len_blocks;
	}
	if (len) {
	(*ctx->gcm_key.block)(ctx->Yi.c, ctx->EKi.c, key);
	++ctr;
	ctx->Yi.d[3] = CRYPTO_bswap4(ctr);
	while (len--) {
	uint8_t c = in[n];
	ctx->Xi.c[n] ^= c;
	out[n] = c ^ ctx->EKi.c[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)(uint64_t Xi[2], const u128 Htable[16]) =
	ctx->gcm_key.gmult;
	#endif

	if (ctx->mres \|\| ctx->ares) {
	GCM_MUL(ctx, Xi);
	}

	ctx->Xi.u[0] ^= CRYPTO_bswap8(ctx->len.u[0] << 3);
	ctx->Xi.u[1] ^= CRYPTO_bswap8(ctx->len.u[1] << 3);
	GCM_MUL(ctx, Xi);

	ctx->Xi.u[0] ^= ctx->EK0.u[0];
	ctx->Xi.u[1] ^= ctx->EK0.u[1];

	if (tag && len <= sizeof(ctx->Xi)) {
	return CRYPTO_memcmp(ctx->Xi.c, 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.c,
	len <= sizeof(ctx->Xi.c) ? len : sizeof(ctx->Xi.c));
	}

	#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