/*

 * Copyright 2010-2018 The OpenSSL Project Authors. All Rights Reserved.

 *

 * Licensed under the Apache License 2.0 (the "License").  You may not use

 * this file except in compliance with the License.  You can obtain a copy

 * in the file LICENSE in the source distribution or at

 * https://www.openssl.org/source/license.html

 */

#include <string.h>

#include <openssl/crypto.h>

#include "internal/cryptlib.h"

#include "crypto/modes.h"

#if defined(BSWAP4) && defined(STRICT_ALIGNMENT)

/* redefine, because alignment is ensured */

# undef  GETU32

# define GETU32(p)       BSWAP4(*(const u32 *)(p))

# undef  PUTU32

# define PUTU32(p,v)     *(u32 *)(p) = BSWAP4(v)

#endif

#define PACK(s)         ((size_t)(s)<<(sizeof(size_t)*8-16))

#define REDUCE1BIT(V)   do { \

        if (sizeof(size_t)==8) { \

                u64 T = U64(0xe100000000000000) & (0-(V.lo&1)); \

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

                V.hi  = (V.hi>>1 )^T; \

        } \

        else { \

                u32 T = 0xe1000000U & (0-(u32)(V.lo&1)); \

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

                V.hi  = (V.hi>>1 )^((u64)T<<32); \

        } \

} while(0)

/*-

 * Even though permitted values for TABLE_BITS are 8, 4 and 1, it should

 * never be set to 8. 8 is effectively reserved for testing purposes.

 * TABLE_BITS>1 are lookup-table-driven implementations referred to as

 * "Shoup's" in GCM specification. In other words OpenSSL does not cover

 * whole spectrum of possible table driven implementations. Why? In

 * non-"Shoup's" case memory access pattern is segmented in such manner,

 * that it's trivial to see that cache timing information can reveal

 * fair portion of intermediate hash value. Given that ciphertext is

 * always available to attacker, it's possible for him to attempt to

 * deduce secret parameter H and if successful, tamper with messages

 * [which is nothing but trivial in CTR mode]. In "Shoup's" case it's

 * not as trivial, but there is no reason to believe that it's resistant

 * to cache-timing attack. And the thing about "8-bit" implementation is

 * that it consumes 16 (sixteen) times more memory, 4KB per individual

 * key + 1KB shared. Well, on pros side it should be twice as fast as

 * "4-bit" version. And for gcc-generated x86[_64] code, "8-bit" version

 * was observed to run ~75% faster, closer to 100% for commercial

 * compilers... Yet "4-bit" procedure is preferred, because it's

 * believed to provide better security-performance balance and adequate

 * all-round performance. "All-round" refers to things like:

 *

 * - shorter setup time effectively improves overall timing for

 *   handling short messages;

 * - larger table allocation can become unbearable because of VM

 *   subsystem penalties (for example on Windows large enough free

 *   results in VM working set trimming, meaning that consequent

 *   malloc would immediately incur working set expansion);

 * - larger table has larger cache footprint, which can affect

 *   performance of other code paths (not necessarily even from same

 *   thread in Hyper-Threading world);

 *

 * Value of 1 is not appropriate for performance reasons.

 */

#if     TABLE_BITS==8

static void gcm_init_8bit(u128 Htable[256], u64 H[2])

{

    int i, j;

    u128 V;

    Htable[0].hi = 0;

    Htable[0].lo = 0;

    V.hi = H[0];

    V.lo = H[1];

    for (Htable[128] = V, i = 64; i > 0; i >>= 1) {

        REDUCE1BIT(V);

        Htable[i] = V;

    }

    for (i = 2; i < 256; i <<= 1) {

        u128 *Hi = Htable + i, H0 = *Hi;

        for (j = 1; j < i; ++j) {

            Hi[j].hi = H0.hi ^ Htable[j].hi;

            Hi[j].lo = H0.lo ^ Htable[j].lo;

        }

    }

}

static void gcm_gmult_8bit(u64 Xi[2], const u128 Htable[256])

{

    u128 Z = { 0, 0 };

    const u8 *xi = (const u8 *)Xi + 15;

    size_t rem, n = *xi;

    const union {

        long one;

        char little;

    } is_endian = { 1 };

    static const size_t rem_8bit[256] = {

        PACK(0x0000), PACK(0x01C2), PACK(0x0384), PACK(0x0246),

        PACK(0x0708), PACK(0x06CA), PACK(0x048C), PACK(0x054E),

        PACK(0x0E10), PACK(0x0FD2), PACK(0x0D94), PACK(0x0C56),

        PACK(0x0918), PACK(0x08DA), PACK(0x0A9C), PACK(0x0B5E),

        PACK(0x1C20), PACK(0x1DE2), PACK(0x1FA4), PACK(0x1E66),

        PACK(0x1B28), PACK(0x1AEA), PACK(0x18AC), PACK(0x196E),

        PACK(0x1230), PACK(0x13F2), PACK(0x11B4), PACK(0x1076),

        PACK(0x1538), PACK(0x14FA), PACK(0x16BC), PACK(0x177E),

        PACK(0x3840), PACK(0x3982), PACK(0x3BC4), PACK(0x3A06),

        PACK(0x3F48), PACK(0x3E8A), PACK(0x3CCC), PACK(0x3D0E),

        PACK(0x3650), PACK(0x3792), PACK(0x35D4), PACK(0x3416),

        PACK(0x3158), PACK(0x309A), PACK(0x32DC), PACK(0x331E),

        PACK(0x2460), PACK(0x25A2), PACK(0x27E4), PACK(0x2626),

        PACK(0x2368), PACK(0x22AA), PACK(0x20EC), PACK(0x212E),

        PACK(0x2A70), PACK(0x2BB2), PACK(0x29F4), PACK(0x2836),

        PACK(0x2D78), PACK(0x2CBA), PACK(0x2EFC), PACK(0x2F3E),

        PACK(0x7080), PACK(0x7142), PACK(0x7304), PACK(0x72C6),

        PACK(0x7788), PACK(0x764A), PACK(0x740C), PACK(0x75CE),

        PACK(0x7E90), PACK(0x7F52), PACK(0x7D14), PACK(0x7CD6),

        PACK(0x7998), PACK(0x785A), PACK(0x7A1C), PACK(0x7BDE),

        PACK(0x6CA0), PACK(0x6D62), PACK(0x6F24), PACK(0x6EE6),

        PACK(0x6BA8), PACK(0x6A6A), PACK(0x682C), PACK(0x69EE),

        PACK(0x62B0), PACK(0x6372), PACK(0x6134), PACK(0x60F6),

        PACK(0x65B8), PACK(0x647A), PACK(0x663C), PACK(0x67FE),

        PACK(0x48C0), PACK(0x4902), PACK(0x4B44), PACK(0x4A86),

        PACK(0x4FC8), PACK(0x4E0A), PACK(0x4C4C), PACK(0x4D8E),

        PACK(0x46D0), PACK(0x4712), PACK(0x4554), PACK(0x4496),

        PACK(0x41D8), PACK(0x401A), PACK(0x425C), PACK(0x439E),

        PACK(0x54E0), PACK(0x5522), PACK(0x5764), PACK(0x56A6),

        PACK(0x53E8), PACK(0x522A), PACK(0x506C), PACK(0x51AE),

        PACK(0x5AF0), PACK(0x5B32), PACK(0x5974), PACK(0x58B6),

        PACK(0x5DF8), PACK(0x5C3A), PACK(0x5E7C), PACK(0x5FBE),

        PACK(0xE100), PACK(0xE0C2), PACK(0xE284), PACK(0xE346),

        PACK(0xE608), PACK(0xE7CA), PACK(0xE58C), PACK(0xE44E),

        PACK(0xEF10), PACK(0xEED2), PACK(0xEC94), PACK(0xED56),

        PACK(0xE818), PACK(0xE9DA), PACK(0xEB9C), PACK(0xEA5E),

        PACK(0xFD20), PACK(0xFCE2), PACK(0xFEA4), PACK(0xFF66),

        PACK(0xFA28), PACK(0xFBEA), PACK(0xF9AC), PACK(0xF86E),

        PACK(0xF330), PACK(0xF2F2), PACK(0xF0B4), PACK(0xF176),

        PACK(0xF438), PACK(0xF5FA), PACK(0xF7BC), PACK(0xF67E),

        PACK(0xD940), PACK(0xD882), PACK(0xDAC4), PACK(0xDB06),

        PACK(0xDE48), PACK(0xDF8A), PACK(0xDDCC), PACK(0xDC0E),

        PACK(0xD750), PACK(0xD692), PACK(0xD4D4), PACK(0xD516),

        PACK(0xD058), PACK(0xD19A), PACK(0xD3DC), PACK(0xD21E),

        PACK(0xC560), PACK(0xC4A2), PACK(0xC6E4), PACK(0xC726),

        PACK(0xC268), PACK(0xC3AA), PACK(0xC1EC), PACK(0xC02E),

        PACK(0xCB70), PACK(0xCAB2), PACK(0xC8F4), PACK(0xC936),

        PACK(0xCC78), PACK(0xCDBA), PACK(0xCFFC), PACK(0xCE3E),

        PACK(0x9180), PACK(0x9042), PACK(0x9204), PACK(0x93C6),

        PACK(0x9688), PACK(0x974A), PACK(0x950C), PACK(0x94CE),

        PACK(0x9F90), PACK(0x9E52), PACK(0x9C14), PACK(0x9DD6),

        PACK(0x9898), PACK(0x995A), PACK(0x9B1C), PACK(0x9ADE),

        PACK(0x8DA0), PACK(0x8C62), PACK(0x8E24), PACK(0x8FE6),

        PACK(0x8AA8), PACK(0x8B6A), PACK(0x892C), PACK(0x88EE),

        PACK(0x83B0), PACK(0x8272), PACK(0x8034), PACK(0x81F6),

        PACK(0x84B8), PACK(0x857A), PACK(0x873C), PACK(0x86FE),

        PACK(0xA9C0), PACK(0xA802), PACK(0xAA44), PACK(0xAB86),

        PACK(0xAEC8), PACK(0xAF0A), PACK(0xAD4C), PACK(0xAC8E),

        PACK(0xA7D0), PACK(0xA612), PACK(0xA454), PACK(0xA596),

        PACK(0xA0D8), PACK(0xA11A), PACK(0xA35C), PACK(0xA29E),

        PACK(0xB5E0), PACK(0xB422), PACK(0xB664), PACK(0xB7A6),

        PACK(0xB2E8), PACK(0xB32A), PACK(0xB16C), PACK(0xB0AE),

        PACK(0xBBF0), PACK(0xBA32), PACK(0xB874), PACK(0xB9B6),

        PACK(0xBCF8), PACK(0xBD3A), PACK(0xBF7C), PACK(0xBEBE)

    };

    while (1) {

        Z.hi ^= Htable[n].hi;

        Z.lo ^= Htable[n].lo;

        if ((u8 *)Xi == xi)

            break;

        n = *(--xi);

        rem = (size_t)Z.lo & 0xff;

        Z.lo = (Z.hi << 56) | (Z.lo >> 8);

        Z.hi = (Z.hi >> 8);

        if (sizeof(size_t) == 8)

            Z.hi ^= rem_8bit[rem];

        else

            Z.hi ^= (u64)rem_8bit[rem] << 32;

    }

    if (is_endian.little) {

# ifdef BSWAP8

        Xi[0] = BSWAP8(Z.hi);

        Xi[1] = BSWAP8(Z.lo);

# else

        u8 *p = (u8 *)Xi;

        u32 v;

        v = (u32)(Z.hi >> 32);

        PUTU32(p, v);

        v = (u32)(Z.hi);

        PUTU32(p + 4, v);

        v = (u32)(Z.lo >> 32);

        PUTU32(p + 8, v);

        v = (u32)(Z.lo);

        PUTU32(p + 12, v);

# endif

    } else {

        Xi[0] = Z.hi;

        Xi[1] = Z.lo;

    }

}

# define GCM_MUL(ctx)      gcm_gmult_8bit(ctx->Xi.u,ctx->Htable)

#elif   TABLE_BITS==4

static void gcm_init_4bit(u128 Htable[16], u64 H[2])

{

    u128 V;

# if defined(OPENSSL_SMALL_FOOTPRINT)

    int i;

# endif

    Htable[0].hi = 0;

    Htable[0].lo = 0;

    V.hi = H[0];

    V.lo = H[1];

# if defined(OPENSSL_SMALL_FOOTPRINT)

    for (Htable[8] = V, i = 4; i > 0; i >>= 1) {

        REDUCE1BIT(V);

        Htable[i] = V;

    }

    for (i = 2; i < 16; i <<= 1) {

        u128 *Hi = Htable + i;

        int j;

        for (V = *Hi, j = 1; j < i; ++j) {

            Hi[j].hi = V.hi ^ Htable[j].hi;

            Hi[j].lo = V.lo ^ Htable[j].lo;

        }

    }

# else

    Htable[8] = V;

    REDUCE1BIT(V);

    Htable[4] = V;

    REDUCE1BIT(V);

    Htable[2] = V;

    REDUCE1BIT(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;

# endif

# if defined(GHASH_ASM) && (defined(__arm__) || defined(__arm))

    /*

     * ARM assembler expects specific dword order in Htable.

     */

    {

        int j;

        const union {

            long one;

            char little;

        } is_endian = { 1 };

        if (is_endian.little)

            for (j = 0; j < 16; ++j) {

                V = Htable[j];

                Htable[j].hi = V.lo;

                Htable[j].lo = V.hi;

        } else

            for (j = 0; j < 16; ++j) {

                V = Htable[j];

                Htable[j].hi = V.lo << 32 | V.lo >> 32;

                Htable[j].lo = V.hi << 32 | V.hi >> 32;

            }

    }

# endif

}

# ifndef GHASH_ASM

static const size_t rem_4bit[16] = {

    PACK(0x0000), PACK(0x1C20), PACK(0x3840), PACK(0x2460),

    PACK(0x7080), PACK(0x6CA0), PACK(0x48C0), PACK(0x54E0),

    PACK(0xE100), PACK(0xFD20), PACK(0xD940), PACK(0xC560),

    PACK(0x9180), PACK(0x8DA0), PACK(0xA9C0), PACK(0xB5E0)

};

static void gcm_gmult_4bit(u64 Xi[2], const u128 Htable[16])

{

    u128 Z;

    int cnt = 15;

    size_t rem, nlo, nhi;

    const union {

        long one;

        char little;

    } is_endian = { 1 };

    nlo = ((const u8 *)Xi)[15];

    nhi = nlo >> 4;

    nlo &= 0xf;

    Z.hi = Htable[nlo].hi;

    Z.lo = Htable[nlo].lo;

    while (1) {

        rem = (size_t)Z.lo & 0xf;

        Z.lo = (Z.hi << 60) | (Z.lo >> 4);

        Z.hi = (Z.hi >> 4);

        if (sizeof(size_t) == 8)

            Z.hi ^= rem_4bit[rem];

        else

            Z.hi ^= (u64)rem_4bit[rem] << 32;

        Z.hi ^= Htable[nhi].hi;

        Z.lo ^= Htable[nhi].lo;

        if (--cnt < 0)

            break;

        nlo = ((const u8 *)Xi)[cnt];

        nhi = nlo >> 4;

        nlo &= 0xf;

        rem = (size_t)Z.lo & 0xf;

        Z.lo = (Z.hi << 60) | (Z.lo >> 4);

        Z.hi = (Z.hi >> 4);

        if (sizeof(size_t) == 8)

            Z.hi ^= rem_4bit[rem];

        else

            Z.hi ^= (u64)rem_4bit[rem] << 32;

        Z.hi ^= Htable[nlo].hi;

        Z.lo ^= Htable[nlo].lo;

    }

    if (is_endian.little) {

#  ifdef BSWAP8

        Xi[0] = BSWAP8(Z.hi);

        Xi[1] = BSWAP8(Z.lo);

#  else

        u8 *p = (u8 *)Xi;

        u32 v;

        v = (u32)(Z.hi >> 32);

        PUTU32(p, v);

        v = (u32)(Z.hi);

        PUTU32(p + 4, v);

        v = (u32)(Z.lo >> 32);

        PUTU32(p + 8, v);

        v = (u32)(Z.lo);

        PUTU32(p + 12, v);

#  endif

    } else {

        Xi[0] = Z.hi;

        Xi[1] = Z.lo;

    }

}

#  if !defined(OPENSSL_SMALL_FOOTPRINT)

/*

 * Streamed gcm_mult_4bit, see CRYPTO_gcm128_[en|de]crypt for

 * details... Compiler-generated code doesn't seem to give any

 * performance improvement, at least not on x86[_64]. It's here

 * mostly as reference and a placeholder for possible future

 * non-trivial optimization[s]...

 */

static void gcm_ghash_4bit(u64 Xi[2], const u128 Htable[16],

                           const u8 *inp, size_t len)

{

    u128 Z;

    int cnt;

    size_t rem, nlo, nhi;

    const union {

        long one;

        char little;

    } is_endian = { 1 };

#   if 1

    do {

        cnt = 15;

        nlo = ((const u8 *)Xi)[15];

        nlo ^= inp[15];

        nhi = nlo >> 4;

        nlo &= 0xf;

        Z.hi = Htable[nlo].hi;

        Z.lo = Htable[nlo].lo;

        while (1) {

            rem = (size_t)Z.lo & 0xf;

            Z.lo = (Z.hi << 60) | (Z.lo >> 4);

            Z.hi = (Z.hi >> 4);

            if (sizeof(size_t) == 8)

                Z.hi ^= rem_4bit[rem];

            else

                Z.hi ^= (u64)rem_4bit[rem] << 32;

            Z.hi ^= Htable[nhi].hi;

            Z.lo ^= Htable[nhi].lo;

            if (--cnt < 0)

                break;

            nlo = ((const u8 *)Xi)[cnt];

            nlo ^= inp[cnt];

            nhi = nlo >> 4;

            nlo &= 0xf;

            rem = (size_t)Z.lo & 0xf;

            Z.lo = (Z.hi << 60) | (Z.lo >> 4);

            Z.hi = (Z.hi >> 4);

            if (sizeof(size_t) == 8)

                Z.hi ^= rem_4bit[rem];

            else

                Z.hi ^= (u64)rem_4bit[rem] << 32;

            Z.hi ^= Htable[nlo].hi;

            Z.lo ^= Htable[nlo].lo;

        }

#   else

    /*

     * Extra 256+16 bytes per-key plus 512 bytes shared tables

     * [should] give ~50% improvement... One could have PACK()-ed

     * the rem_8bit even here, but the priority is to minimize

     * cache footprint...

     */

    u128 Hshr4[16];             /* Htable shifted right by 4 bits */

    u8 Hshl4[16];               /* Htable shifted left by 4 bits */

    static const unsigned short rem_8bit[256] = {

        0x0000, 0x01C2, 0x0384, 0x0246, 0x0708, 0x06CA, 0x048C, 0x054E,

        0x0E10, 0x0FD2, 0x0D94, 0x0C56, 0x0918, 0x08DA, 0x0A9C, 0x0B5E,

        0x1C20, 0x1DE2, 0x1FA4, 0x1E66, 0x1B28, 0x1AEA, 0x18AC, 0x196E,

        0x1230, 0x13F2, 0x11B4, 0x1076, 0x1538, 0x14FA, 0x16BC, 0x177E,

        0x3840, 0x3982, 0x3BC4, 0x3A06, 0x3F48, 0x3E8A, 0x3CCC, 0x3D0E,

        0x3650, 0x3792, 0x35D4, 0x3416, 0x3158, 0x309A, 0x32DC, 0x331E,

        0x2460, 0x25A2, 0x27E4, 0x2626, 0x2368, 0x22AA, 0x20EC, 0x212E,

        0x2A70, 0x2BB2, 0x29F4, 0x2836, 0x2D78, 0x2CBA, 0x2EFC, 0x2F3E,

        0x7080, 0x7142, 0x7304, 0x72C6, 0x7788, 0x764A, 0x740C, 0x75CE,

        0x7E90, 0x7F52, 0x7D14, 0x7CD6, 0x7998, 0x785A, 0x7A1C, 0x7BDE,

        0x6CA0, 0x6D62, 0x6F24, 0x6EE6, 0x6BA8, 0x6A6A, 0x682C, 0x69EE,

        0x62B0, 0x6372, 0x6134, 0x60F6, 0x65B8, 0x647A, 0x663C, 0x67FE,

        0x48C0, 0x4902, 0x4B44, 0x4A86, 0x4FC8, 0x4E0A, 0x4C4C, 0x4D8E,

        0x46D0, 0x4712, 0x4554, 0x4496, 0x41D8, 0x401A, 0x425C, 0x439E,

        0x54E0, 0x5522, 0x5764, 0x56A6, 0x53E8, 0x522A, 0x506C, 0x51AE,

        0x5AF0, 0x5B32, 0x5974, 0x58B6, 0x5DF8, 0x5C3A, 0x5E7C, 0x5FBE,

        0xE100, 0xE0C2, 0xE284, 0xE346, 0xE608, 0xE7CA, 0xE58C, 0xE44E,

        0xEF10, 0xEED2, 0xEC94, 0xED56, 0xE818, 0xE9DA, 0xEB9C, 0xEA5E,

        0xFD20, 0xFCE2, 0xFEA4, 0xFF66, 0xFA28, 0xFBEA, 0xF9AC, 0xF86E,

        0xF330, 0xF2F2, 0xF0B4, 0xF176, 0xF438, 0xF5FA, 0xF7BC, 0xF67E,

        0xD940, 0xD882, 0xDAC4, 0xDB06, 0xDE48, 0xDF8A, 0xDDCC, 0xDC0E,

        0xD750, 0xD692, 0xD4D4, 0xD516, 0xD058, 0xD19A, 0xD3DC, 0xD21E,

        0xC560, 0xC4A2, 0xC6E4, 0xC726, 0xC268, 0xC3AA, 0xC1EC, 0xC02E,

        0xCB70, 0xCAB2, 0xC8F4, 0xC936, 0xCC78, 0xCDBA, 0xCFFC, 0xCE3E,

        0x9180, 0x9042, 0x9204, 0x93C6, 0x9688, 0x974A, 0x950C, 0x94CE,

        0x9F90, 0x9E52, 0x9C14, 0x9DD6, 0x9898, 0x995A, 0x9B1C, 0x9ADE,

        0x8DA0, 0x8C62, 0x8E24, 0x8FE6, 0x8AA8, 0x8B6A, 0x892C, 0x88EE,

        0x83B0, 0x8272, 0x8034, 0x81F6, 0x84B8, 0x857A, 0x873C, 0x86FE,

        0xA9C0, 0xA802, 0xAA44, 0xAB86, 0xAEC8, 0xAF0A, 0xAD4C, 0xAC8E,

        0xA7D0, 0xA612, 0xA454, 0xA596, 0xA0D8, 0xA11A, 0xA35C, 0xA29E,

        0xB5E0, 0xB422, 0xB664, 0xB7A6, 0xB2E8, 0xB32A, 0xB16C, 0xB0AE,

        0xBBF0, 0xBA32, 0xB874, 0xB9B6, 0xBCF8, 0xBD3A, 0xBF7C, 0xBEBE

    };

    /*

     * This pre-processing phase slows down procedure by approximately

     * same time as it makes each loop spin faster. In other words

     * single block performance is approximately same as straightforward

     * "4-bit" implementation, and then it goes only faster...

     */

    for (cnt = 0; cnt < 16; ++cnt) {

        Z.hi = Htable[cnt].hi;

        Z.lo = Htable[cnt].lo;

        Hshr4[cnt].lo = (Z.hi << 60) | (Z.lo >> 4);

        Hshr4[cnt].hi = (Z.hi >> 4);

        Hshl4[cnt] = (u8)(Z.lo << 4);

    }

    do {

        for (Z.lo = 0, Z.hi = 0, cnt = 15; cnt; --cnt) {

            nlo = ((const u8 *)Xi)[cnt];

            nlo ^= inp[cnt];

            nhi = nlo >> 4;

            nlo &= 0xf;

            Z.hi ^= Htable[nlo].hi;

            Z.lo ^= Htable[nlo].lo;

            rem = (size_t)Z.lo & 0xff;

            Z.lo = (Z.hi << 56) | (Z.lo >> 8);

            Z.hi = (Z.hi >> 8);

            Z.hi ^= Hshr4[nhi].hi;

            Z.lo ^= Hshr4[nhi].lo;

            Z.hi ^= (u64)rem_8bit[rem ^ Hshl4[nhi]] << 48;

        }

        nlo = ((const u8 *)Xi)[0];

        nlo ^= inp[0];

        nhi = nlo >> 4;

        nlo &= 0xf;

        Z.hi ^= Htable[nlo].hi;

        Z.lo ^= Htable[nlo].lo;

        rem = (size_t)Z.lo & 0xf;

        Z.lo = (Z.hi << 60) | (Z.lo >> 4);

        Z.hi = (Z.hi >> 4);

        Z.hi ^= Htable[nhi].hi;

        Z.lo ^= Htable[nhi].lo;

        Z.hi ^= ((u64)rem_8bit[rem << 4]) << 48;

#   endif

        if (is_endian.little) {

#   ifdef BSWAP8

            Xi[0] = BSWAP8(Z.hi);

            Xi[1] = BSWAP8(Z.lo);

#   else

            u8 *p = (u8 *)Xi;

            u32 v;

            v = (u32)(Z.hi >> 32);

            PUTU32(p, v);

            v = (u32)(Z.hi);

            PUTU32(p + 4, v);

            v = (u32)(Z.lo >> 32);

            PUTU32(p + 8, v);

            v = (u32)(Z.lo);

            PUTU32(p + 12, v);

#   endif

        } else {

            Xi[0] = Z.hi;

            Xi[1] = Z.lo;

        }

    } while (inp += 16, len -= 16);

}

#  endif

# else

void gcm_gmult_4bit(u64 Xi[2], const u128 Htable[16]);

void gcm_ghash_4bit(u64 Xi[2], const u128 Htable[16], const u8 *inp,

                    size_t len);

# endif

# define GCM_MUL(ctx)      gcm_gmult_4bit(ctx->Xi.u,ctx->Htable)

# if defined(GHASH_ASM) || !defined(OPENSSL_SMALL_FOOTPRINT)

#  define GHASH(ctx,in,len) gcm_ghash_4bit((ctx)->Xi.u,(ctx)->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)

# endif

#else                           /* TABLE_BITS */

static void gcm_gmult_1bit(u64 Xi[2], const u64 H[2])

{

    u128 V, Z = { 0, 0 };

    long X;

    int i, j;

    const long *xi = (const long *)Xi;

    const union {

        long one;

        char little;

    } is_endian = { 1 };

    V.hi = H[0];                /* H is in host byte order, no byte swapping */

    V.lo = H[1];

    for (j = 0; j < 16 / sizeof(long); ++j) {

        if (is_endian.little) {

            if (sizeof(long) == 8) {

# ifdef BSWAP8

                X = (long)(BSWAP8(xi[j]));

# else

                const u8 *p = (const u8 *)(xi + j);

                X = (long)((u64)GETU32(p) << 32 | GETU32(p + 4));

# endif

            } else {

                const u8 *p = (const u8 *)(xi + j);

                X = (long)GETU32(p);

            }

        } else

            X = xi[j];

        for (i = 0; i < 8 * sizeof(long); ++i, X <<= 1) {

            u64 M = (u64)(X >> (8 * sizeof(long) - 1));

            Z.hi ^= V.hi & M;

            Z.lo ^= V.lo & M;

            REDUCE1BIT(V);

        }

    }

    if (is_endian.little) {

# ifdef BSWAP8

        Xi[0] = BSWAP8(Z.hi);

        Xi[1] = BSWAP8(Z.lo);

# else

        u8 *p = (u8 *)Xi;

        u32 v;

        v = (u32)(Z.hi >> 32);

        PUTU32(p, v);

        v = (u32)(Z.hi);

        PUTU32(p + 4, v);

        v = (u32)(Z.lo >> 32);

        PUTU32(p + 8, v);

        v = (u32)(Z.lo);

        PUTU32(p + 12, v);

# endif

    } else {

        Xi[0] = Z.hi;

        Xi[1] = Z.lo;

    }

}

# define GCM_MUL(ctx)      gcm_gmult_1bit(ctx->Xi.u,ctx->H.u)

#endif

#if     TABLE_BITS==4 && (defined(GHASH_ASM) || defined(OPENSSL_CPUID_OBJ))

# if    !defined(I386_ONLY) && \

        (defined(__i386)        || defined(__i386__)    || \

         defined(__x86_64)      || defined(__x86_64__)  || \

         defined(_M_IX86)       || defined(_M_AMD64)    || defined(_M_X64))

#  define GHASH_ASM_X86_OR_64

#  define GCM_FUNCREF_4BIT

void gcm_init_clmul(u128 Htable[16], const u64 Xi[2]);

void gcm_gmult_clmul(u64 Xi[2], const u128 Htable[16]);

void gcm_ghash_clmul(u64 Xi[2], const u128 Htable[16], const u8 *inp,

                     size_t len);

#  if defined(__i386) || defined(__i386__) || defined(_M_IX86)

#   define gcm_init_avx   gcm_init_clmul

#   define gcm_gmult_avx  gcm_gmult_clmul

#   define gcm_ghash_avx  gcm_ghash_clmul

#  else

void gcm_init_avx(u128 Htable[16], const u64 Xi[2]);

void gcm_gmult_avx(u64 Xi[2], const u128 Htable[16]);

void gcm_ghash_avx(u64 Xi[2], const u128 Htable[16], const u8 *inp,

                   size_t len);

#  endif

#  if   defined(__i386) || defined(__i386__) || defined(_M_IX86)

#   define GHASH_ASM_X86

void gcm_gmult_4bit_mmx(u64 Xi[2], const u128 Htable[16]);

void gcm_ghash_4bit_mmx(u64 Xi[2], const u128 Htable[16], const u8 *inp,

                        size_t len);

void gcm_gmult_4bit_x86(u64 Xi[2], const u128 Htable[16]);

void gcm_ghash_4bit_x86(u64 Xi[2], const u128 Htable[16], const u8 *inp,

                        size_t len);

#  endif

# elif defined(__arm__) || defined(__arm) || defined(__aarch64__)

#  include "arm_arch.h"

#  if __ARM_MAX_ARCH__>=7

#   define GHASH_ASM_ARM

#   define GCM_FUNCREF_4BIT

#   define PMULL_CAPABLE        (OPENSSL_armcap_P & ARMV8_PMULL)

#   if defined(__arm__) || defined(__arm)

#    define NEON_CAPABLE        (OPENSSL_armcap_P & ARMV7_NEON)

#   endif

void gcm_init_neon(u128 Htable[16], const u64 Xi[2]);

void gcm_gmult_neon(u64 Xi[2], const u128 Htable[16]);

void gcm_ghash_neon(u64 Xi[2], const u128 Htable[16], const u8 *inp,

                    size_t len);

void gcm_init_v8(u128 Htable[16], const u64 Xi[2]);

void gcm_gmult_v8(u64 Xi[2], const u128 Htable[16]);

void gcm_ghash_v8(u64 Xi[2], const u128 Htable[16], const u8 *inp,

                  size_t len);

#  endif

# elif defined(__sparc__) || defined(__sparc)

#  include "sparc_arch.h"

#  define GHASH_ASM_SPARC

#  define GCM_FUNCREF_4BIT

extern unsigned int OPENSSL_sparcv9cap_P[];

void gcm_init_vis3(u128 Htable[16], const u64 Xi[2]);

void gcm_gmult_vis3(u64 Xi[2], const u128 Htable[16]);

void gcm_ghash_vis3(u64 Xi[2], const u128 Htable[16], const u8 *inp,

                    size_t len);

# elif defined(OPENSSL_CPUID_OBJ) && (defined(__powerpc__) || defined(__ppc__) || defined(_ARCH_PPC))

#  include "ppc_arch.h"

#  define GHASH_ASM_PPC

#  define GCM_FUNCREF_4BIT

void gcm_init_p8(u128 Htable[16], const u64 Xi[2]);

void gcm_gmult_p8(u64 Xi[2], const u128 Htable[16]);

void gcm_ghash_p8(u64 Xi[2], const u128 Htable[16], const u8 *inp,

                  size_t len);

# endif

#endif

#ifdef GCM_FUNCREF_4BIT

# undef  GCM_MUL

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

# ifdef GHASH

#  undef  GHASH

#  define GHASH(ctx,in,len)     (*gcm_ghash_p)(ctx->Xi.u,ctx->Htable,in,len)

# endif

#endif

void CRYPTO_gcm128_init(GCM128_CONTEXT *ctx, void *key, block128_f block)

{

    const union {

        long one;

        char little;

    } is_endian = { 1 };

    memset(ctx, 0, sizeof(*ctx));

    ctx->block = block;

    ctx->key = key;

    (*block) (ctx->H.c, ctx->H.c, key);

    if (is_endian.little) {

        /* H is stored in host byte order */

#ifdef BSWAP8

        ctx->H.u[0] = BSWAP8(ctx->H.u[0]);

        ctx->H.u[1] = BSWAP8(ctx->H.u[1]);

#else

        u8 *p = ctx->H.c;

        u64 hi, lo;

        hi = (u64)GETU32(p) << 32 | GETU32(p + 4);

        lo = (u64)GETU32(p + 8) << 32 | GETU32(p + 12);

        ctx->H.u[0] = hi;

        ctx->H.u[1] = lo;

#endif

    }

#if     TABLE_BITS==8

    gcm_init_8bit(ctx->Htable, ctx->H.u);

#elif   TABLE_BITS==4

# if    defined(GHASH)

#  define CTX__GHASH(f) (ctx->ghash = (f))

# else

#  define CTX__GHASH(f) (ctx->ghash = NULL)

# endif

# if    defined(GHASH_ASM_X86_OR_64)

#  if   !defined(GHASH_ASM_X86) || defined(OPENSSL_IA32_SSE2)

    if (OPENSSL_ia32cap_P[1] & (1 << 1)) { /* check PCLMULQDQ bit */

        if (((OPENSSL_ia32cap_P[1] >> 22) & 0x41) == 0x41) { /* AVX+MOVBE */

            gcm_init_avx(ctx->Htable, ctx->H.u);

            ctx->gmult = gcm_gmult_avx;

            CTX__GHASH(gcm_ghash_avx);

        } else {

            gcm_init_clmul(ctx->Htable, ctx->H.u);

            ctx->gmult = gcm_gmult_clmul;

            CTX__GHASH(gcm_ghash_clmul);

        }

        return;

    }

#  endif

    gcm_init_4bit(ctx->Htable, ctx->H.u);

#  if   defined(GHASH_ASM_X86)  /* x86 only */

#   if  defined(OPENSSL_IA32_SSE2)

    if (OPENSSL_ia32cap_P[0] & (1 << 25)) { /* check SSE bit */

#   else

    if (OPENSSL_ia32cap_P[0] & (1 << 23)) { /* check MMX bit */

#   endif

        ctx->gmult = gcm_gmult_4bit_mmx;

        CTX__GHASH(gcm_ghash_4bit_mmx);

    } else {

        ctx->gmult = gcm_gmult_4bit_x86;

        CTX__GHASH(gcm_ghash_4bit_x86);

    }

#  else

    ctx->gmult = gcm_gmult_4bit;

    CTX__GHASH(gcm_ghash_4bit);

#  endif

# elif  defined(GHASH_ASM_ARM)

#  ifdef PMULL_CAPABLE

    if (PMULL_CAPABLE) {

        gcm_init_v8(ctx->Htable, ctx->H.u);

        ctx->gmult = gcm_gmult_v8;

        CTX__GHASH(gcm_ghash_v8);

    } else

#  endif

#  ifdef NEON_CAPABLE

    if (NEON_CAPABLE) {

        gcm_init_neon(ctx->Htable, ctx->H.u);

        ctx->gmult = gcm_gmult_neon;

        CTX__GHASH(gcm_ghash_neon);

    } else

#  endif

    {

        gcm_init_4bit(ctx->Htable, ctx->H.u);

        ctx->gmult = gcm_gmult_4bit;

        CTX__GHASH(gcm_ghash_4bit);

    }

# elif  defined(GHASH_ASM_SPARC)

    if (OPENSSL_sparcv9cap_P[0] & SPARCV9_VIS3) {

        gcm_init_vis3(ctx->Htable, ctx->H.u);

        ctx->gmult = gcm_gmult_vis3;

        CTX__GHASH(gcm_ghash_vis3);

    } else {

        gcm_init_4bit(ctx->Htable, ctx->H.u);

        ctx->gmult = gcm_gmult_4bit;

        CTX__GHASH(gcm_ghash_4bit);

    }

# elif  defined(GHASH_ASM_PPC)

    if (OPENSSL_ppccap_P & PPC_CRYPTO207) {

        gcm_init_p8(ctx->Htable, ctx->H.u);

        ctx->gmult = gcm_gmult_p8;

        CTX__GHASH(gcm_ghash_p8);

    } else {

        gcm_init_4bit(ctx->Htable, ctx->H.u);

        ctx->gmult = gcm_gmult_4bit;

        CTX__GHASH(gcm_ghash_4bit);

    }

# else

    gcm_init_4bit(ctx->Htable, ctx->H.u);

# endif

# undef CTX__GHASH

#endif

}

void CRYPTO_gcm128_setiv(GCM128_CONTEXT *ctx, const unsigned char *iv,

                         size_t len)

{

    const union {

        long one;

        char little;

    } is_endian = { 1 };

    unsigned int ctr;

#ifdef GCM_FUNCREF_4BIT

    void (*gcm_gmult_p) (u64 Xi[2], const u128 Htable[16]) = ctx->gmult;

#endif

    ctx->len.u[0] = 0;          /* AAD length */

    ctx->len.u[1] = 0;          /* message length */

    ctx->ares = 0;

    ctx->mres = 0;

    if (len == 12) {

        memcpy(ctx->Yi.c, iv, 12);

        ctx->Yi.c[12] = 0;

        ctx->Yi.c[13] = 0;

        ctx->Yi.c[14] = 0;

        ctx->Yi.c[15] = 1;

        ctr = 1;

    } else {

        size_t i;

        u64 len0 = len;

        /* Borrow ctx->Xi to calculate initial Yi */

        ctx->Xi.u[0] = 0;

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

        while (len >= 16) {

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

                ctx->Xi.c[i] ^= iv[i];

            GCM_MUL(ctx);

            iv += 16;

            len -= 16;

        }

        if (len) {

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

                ctx->Xi.c[i] ^= iv[i];

            GCM_MUL(ctx);

        }

        len0 <<= 3;

        if (is_endian.little) {

#ifdef BSWAP8

            ctx->Xi.u[1] ^= BSWAP8(len0);

#else

            ctx->Xi.c[8] ^= (u8)(len0 >> 56);

            ctx->Xi.c[9] ^= (u8)(len0 >> 48);

            ctx->Xi.c[10] ^= (u8)(len0 >> 40);

            ctx->Xi.c[11] ^= (u8)(len0 >> 32);

            ctx->Xi.c[12] ^= (u8)(len0 >> 24);

            ctx->Xi.c[13] ^= (u8)(len0 >> 16);

            ctx->Xi.c[14] ^= (u8)(len0 >> 8);

            ctx->Xi.c[15] ^= (u8)(len0);

#endif

        } else {

            ctx->Xi.u[1] ^= len0;

        }

        GCM_MUL(ctx);

        if (is_endian.little)

#ifdef BSWAP4

            ctr = BSWAP4(ctx->Xi.d[3]);

#else

            ctr = GETU32(ctx->Xi.c + 12);

#endif

        else

            ctr = ctx->Xi.d[3];

        /* Copy borrowed Xi to Yi */

        ctx->Yi.u[0] = ctx->Xi.u[0];

        ctx->Yi.u[1] = ctx->Xi.u[1];

    }

    ctx->Xi.u[0] = 0;

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

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

    ++ctr;

    if (is_endian.little)

#ifdef BSWAP4

        ctx->Yi.d[3] = BSWAP4(ctr);

#else

        PUTU32(ctx->Yi.c + 12, ctr);

#endif

    else

        ctx->Yi.d[3] = ctr;

}

int CRYPTO_gcm128_aad(GCM128_CONTEXT *ctx, const unsigned char *aad,

                      size_t len)

{

    size_t i;

    unsigned int n;

    u64 alen = ctx->len.u[0];

#ifdef GCM_FUNCREF_4BIT

    void (*gcm_gmult_p) (u64 Xi[2], const u128 Htable[16]) = ctx->gmult;

# ifdef GHASH

    void (*gcm_ghash_p) (u64 Xi[2], const u128 Htable[16],

                         const u8 *inp, size_t len) = ctx->ghash;

# endif

#endif

    if (ctx->len.u[1])

        return -2;

    alen += len;

    if (alen > (U64(1) << 61) || (sizeof(len) == 8 && alen < len))

        return -1;

    ctx->len.u[0] = alen;

    n = ctx->ares;

    if (n) {

        while (n && len) {

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

            --len;

            n = (n + 1) % 16;

        }

        if (n == 0)

            GCM_MUL(ctx);

        else {

            ctx->ares = n;

            return 0;

        }

    }

#ifdef GHASH

    if ((i = (len & (size_t)-16))) {

        GHASH(ctx, aad, i);

        aad += i;

        len -= i;

    }

#else

    while (len >= 16) {

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

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

        GCM_MUL(ctx);

        aad += 16;

        len -= 16;

    }

#endif

    if (len) {

        n = (unsigned int)len;

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

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

    }

    ctx->ares = n;

    return 0;

}

int CRYPTO_gcm128_encrypt(GCM128_CONTEXT *ctx,

                          const unsigned char *in, unsigned char *out,

                          size_t len)

{

    const union {

        long one;

        char little;

    } is_endian = { 1 };

    unsigned int n, ctr, mres;

    size_t i;

    u64 mlen = ctx->len.u[1];

    block128_f block = ctx->block;

    void *key = ctx->key;

#ifdef GCM_FUNCREF_4BIT

    void (*gcm_gmult_p) (u64 Xi[2], const u128 Htable[16]) = ctx->gmult;

# if defined(GHASH) && !defined(OPENSSL_SMALL_FOOTPRINT)

    void (*gcm_ghash_p) (u64 Xi[2], const u128 Htable[16],

                         const u8 *inp, size_t len) = ctx->ghash;

# endif

#endif

    mlen += len;

    if (mlen > ((U64(1) << 36) - 32) || (sizeof(len) == 8 && mlen < len))

        return -1;

    ctx->len.u[1] = mlen;

    mres = ctx->mres;

    if (ctx->ares) {

        /* First call to encrypt finalizes GHASH(AAD) */

#if defined(GHASH) && !defined(OPENSSL_SMALL_FOOTPRINT)

        if (len == 0) {

            GCM_MUL(ctx);

            ctx->ares = 0;

            return 0;

        }

        memcpy(ctx->Xn, ctx->Xi.c, sizeof(ctx->Xi));

        ctx->Xi.u[0] = 0;

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

        mres = sizeof(ctx->Xi);

#else

        GCM_MUL(ctx);

#endif

        ctx->ares = 0;

    }

    if (is_endian.little)

#ifdef BSWAP4

        ctr = BSWAP4(ctx->Yi.d[3]);

#else

        ctr = GETU32(ctx->Yi.c + 12);

#endif

    else

        ctr = ctx->Yi.d[3];

    n = mres % 16;

#if !defined(OPENSSL_SMALL_FOOTPRINT)

    if (16 % sizeof(size_t) == 0) { /* always true actually */

        do {

            if (n) {

# if defined(GHASH)