/*

 * Copyright 2010-2024 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 "internal/endian.h"

#include "crypto/modes.h"

#if defined(__GNUC__) && !defined(STRICT_ALIGNMENT)

typedef size_t size_t_aX __attribute((__aligned__(1)));

#else

typedef size_t size_t_aX;

#endif

#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

/* RISC-V uses C implementation as a fallback. */

#if defined(__riscv)

# define INCLUDE_C_GMULT_4BIT

# define INCLUDE_C_GHASH_4BIT

#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)

/*-

 *

 * NOTE: TABLE_BITS and all non-4bit implementations have been removed in 3.1.

 *

 * 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.

 */

static void gcm_init_4bit(u128 Htable[16], const 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;

        DECLARE_IS_ENDIAN;

        if (IS_LITTLE_ENDIAN)

            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

}

# if !defined(GHASH_ASM) || defined(INCLUDE_C_GMULT_4BIT)

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;

    DECLARE_IS_ENDIAN;

    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_LITTLE_ENDIAN) {

#  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;

    }

}

# endif

# if !defined(GHASH_ASM) || defined(INCLUDE_C_GHASH_4BIT)

#  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;

    DECLARE_IS_ENDIAN;

    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;

        }

        if (IS_LITTLE_ENDIAN) {

#   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;

        }

        inp += 16;

        /* Block size is 128 bits so len is a multiple of 16 */

        len -= 16;

    } while (len > 0);

}

#  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)      ctx->funcs.gmult(ctx->Xi.u,ctx->Htable)

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

#  define GHASH(ctx,in,len) ctx->funcs.ghash((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

#if     (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

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__) || defined(_M_ARM64)

#  include "arm_arch.h"

#  if __ARM_MAX_ARCH__>=7

#   define GHASH_ASM_ARM

#   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 "crypto/sparc_arch.h"

#  define GHASH_ASM_SPARC

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(__POWERPC__) || defined(_ARCH_PPC))

#  include "crypto/ppc_arch.h"

#  define GHASH_ASM_PPC

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);

# elif defined(OPENSSL_CPUID_OBJ) && defined(__riscv) && __riscv_xlen == 64

#  include "crypto/riscv_arch.h"

#  define GHASH_ASM_RV64I

/* Zbc/Zbkc (scalar crypto with clmul) based routines. */

void gcm_init_rv64i_zbc(u128 Htable[16], const u64 Xi[2]);

void gcm_init_rv64i_zbc__zbb(u128 Htable[16], const u64 Xi[2]);

void gcm_init_rv64i_zbc__zbkb(u128 Htable[16], const u64 Xi[2]);

void gcm_gmult_rv64i_zbc(u64 Xi[2], const u128 Htable[16]);

void gcm_gmult_rv64i_zbc__zbkb(u64 Xi[2], const u128 Htable[16]);

void gcm_ghash_rv64i_zbc(u64 Xi[2], const u128 Htable[16],

                         const u8 *inp, size_t len);

void gcm_ghash_rv64i_zbc__zbkb(u64 Xi[2], const u128 Htable[16],

                               const u8 *inp, size_t len);

/* zvkb/Zvbc (vector crypto with vclmul) based routines. */

void gcm_init_rv64i_zvkb_zvbc(u128 Htable[16], const u64 Xi[2]);

void gcm_gmult_rv64i_zvkb_zvbc(u64 Xi[2], const u128 Htable[16]);

void gcm_ghash_rv64i_zvkb_zvbc(u64 Xi[2], const u128 Htable[16],

                               const u8 *inp, size_t len);

/* Zvkg (vector crypto with vgmul.vv and vghsh.vv). */

void gcm_init_rv64i_zvkg(u128 Htable[16], const u64 Xi[2]);

void gcm_init_rv64i_zvkg_zvkb(u128 Htable[16], const u64 Xi[2]);

void gcm_gmult_rv64i_zvkg(u64 Xi[2], const u128 Htable[16]);

void gcm_ghash_rv64i_zvkg(u64 Xi[2], const u128 Htable[16],

                          const u8 *inp, size_t len);

# endif

#endif

static void gcm_get_funcs(struct gcm_funcs_st *ctx)

{

    /* set defaults -- overridden below as needed */

    ctx->ginit = gcm_init_4bit;

#if !defined(GHASH_ASM)

    ctx->gmult = gcm_gmult_4bit;

#else

    ctx->gmult = NULL;

#endif

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

    ctx->ghash = gcm_ghash_4bit;

#else

    ctx->ghash = NULL;

#endif

#if defined(GHASH_ASM_X86_OR_64)

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

    /* x86_64 */

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

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

            ctx->ginit = gcm_init_avx;

            ctx->gmult = gcm_gmult_avx;

            ctx->ghash = gcm_ghash_avx;

        } else {

            ctx->ginit = gcm_init_clmul;

            ctx->gmult = gcm_gmult_clmul;

            ctx->ghash = gcm_ghash_clmul;

        }

        return;

    }

# endif

# if defined(GHASH_ASM_X86)

    /* x86 only */

#  if defined(OPENSSL_IA32_SSE2)

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

        ctx->gmult = gcm_gmult_4bit_mmx;

        ctx->ghash = gcm_ghash_4bit_mmx;

        return;

    }

#  else

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

        ctx->gmult = gcm_gmult_4bit_mmx;

        ctx->ghash = gcm_ghash_4bit_mmx;

        return;

    }

#  endif

    ctx->gmult = gcm_gmult_4bit_x86;

    ctx->ghash = gcm_ghash_4bit_x86;

    return;

# else

    /* x86_64 fallback defaults */

    ctx->gmult = gcm_gmult_4bit;

    ctx->ghash = gcm_ghash_4bit;

    return;

# endif

#elif defined(GHASH_ASM_ARM)

    /* ARM defaults */

    ctx->gmult = gcm_gmult_4bit;

# if !defined(OPENSSL_SMALL_FOOTPRINT)

    ctx->ghash = gcm_ghash_4bit;

# else

    ctx->ghash = NULL;

# endif

# ifdef PMULL_CAPABLE

    if (PMULL_CAPABLE) {

        ctx->ginit = (gcm_init_fn)gcm_init_v8;

        ctx->gmult = gcm_gmult_v8;

        ctx->ghash = gcm_ghash_v8;

    }

# elif defined(NEON_CAPABLE)

    if (NEON_CAPABLE) {

        ctx->ginit = gcm_init_neon;

        ctx->gmult = gcm_gmult_neon;

        ctx->ghash = gcm_ghash_neon;

    }

# endif

    return;

#elif defined(GHASH_ASM_SPARC)

    /* SPARC defaults */

    ctx->gmult = gcm_gmult_4bit;

    ctx->ghash = gcm_ghash_4bit;

    if (OPENSSL_sparcv9cap_P[0] & SPARCV9_VIS3) {

        ctx->ginit = gcm_init_vis3;

        ctx->gmult = gcm_gmult_vis3;

        ctx->ghash = gcm_ghash_vis3;

    }

    return;

#elif defined(GHASH_ASM_PPC)

    /* PowerPC does not define GHASH_ASM; defaults set above */

    if (OPENSSL_ppccap_P & PPC_CRYPTO207) {

        ctx->ginit = gcm_init_p8;

        ctx->gmult = gcm_gmult_p8;

        ctx->ghash = gcm_ghash_p8;

    }

    return;

#elif defined(GHASH_ASM_RV64I)

    /* RISCV defaults */

    ctx->gmult = gcm_gmult_4bit;

    ctx->ghash = gcm_ghash_4bit;

    if (RISCV_HAS_ZVKG() && riscv_vlen() >= 128) {

        if (RISCV_HAS_ZVKB())

            ctx->ginit = gcm_init_rv64i_zvkg_zvkb;

        else

            ctx->ginit = gcm_init_rv64i_zvkg;

        ctx->gmult = gcm_gmult_rv64i_zvkg;

        ctx->ghash = gcm_ghash_rv64i_zvkg;

    } else if (RISCV_HAS_ZVKB() && RISCV_HAS_ZVBC() && riscv_vlen() >= 128) {

        ctx->ginit = gcm_init_rv64i_zvkb_zvbc;

        ctx->gmult = gcm_gmult_rv64i_zvkb_zvbc;

        ctx->ghash = gcm_ghash_rv64i_zvkb_zvbc;

    } else if (RISCV_HAS_ZBC()) {

        if (RISCV_HAS_ZBKB()) {

            ctx->ginit = gcm_init_rv64i_zbc__zbkb;

            ctx->gmult = gcm_gmult_rv64i_zbc__zbkb;

            ctx->ghash = gcm_ghash_rv64i_zbc__zbkb;

        } else if (RISCV_HAS_ZBB()) {

            ctx->ginit = gcm_init_rv64i_zbc__zbb;

            ctx->gmult = gcm_gmult_rv64i_zbc;

            ctx->ghash = gcm_ghash_rv64i_zbc;

        } else {

            ctx->ginit = gcm_init_rv64i_zbc;

            ctx->gmult = gcm_gmult_rv64i_zbc;

            ctx->ghash = gcm_ghash_rv64i_zbc;

        }

    }

    return;

#elif defined(GHASH_ASM)

    /* all other architectures use the generic names */

    ctx->gmult = gcm_gmult_4bit;

    ctx->ghash = gcm_ghash_4bit;

    return;

#endif

}

void ossl_gcm_init_4bit(u128 Htable[16], const u64 H[2])

{

    struct gcm_funcs_st funcs;

    gcm_get_funcs(&funcs);

    funcs.ginit(Htable, H);

}

void ossl_gcm_gmult_4bit(u64 Xi[2], const u128 Htable[16])

{

    struct gcm_funcs_st funcs;

    gcm_get_funcs(&funcs);

    funcs.gmult(Xi, Htable);

}

void ossl_gcm_ghash_4bit(u64 Xi[2], const u128 Htable[16],

                         const u8 *inp, size_t len)

{

    struct gcm_funcs_st funcs;

    u64 tmp[2];

    size_t i;

    gcm_get_funcs(&funcs);

    if (funcs.ghash != NULL) {

        funcs.ghash(Xi, Htable, inp, len);

    } else {

        /* Emulate ghash if needed */

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

            memcpy(tmp, &inp[i], sizeof(tmp));

            Xi[0] ^= tmp[0];

            Xi[1] ^= tmp[1];

            funcs.gmult(Xi, Htable);

        }

    }

}

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

{

    DECLARE_IS_ENDIAN;

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

    ctx->block = block;

    ctx->key = key;

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

    if (IS_LITTLE_ENDIAN) {

        /* 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

    }

    gcm_get_funcs(&ctx->funcs);

    ctx->funcs.ginit(ctx->Htable, ctx->H.u);

}

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

                         size_t len)

{

    DECLARE_IS_ENDIAN;

    unsigned int ctr;

    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_LITTLE_ENDIAN) {

#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_LITTLE_ENDIAN)

#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_LITTLE_ENDIAN)

#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];

    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)

{

    DECLARE_IS_ENDIAN;

    unsigned int n, ctr, mres;

    size_t i;

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

    block128_f block = ctx->block;

    void *key = ctx->key;

    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_LITTLE_ENDIAN)

#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)

                while (n && len) {

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

                    --len;

                    n = (n + 1) % 16;

                }

                if (n == 0) {

                    GHASH(ctx, ctx->Xn, mres);

                    mres = 0;

                } else {

                    ctx->mres = mres;

                    return 0;

                }

# else

                while (n && len) {

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

                    --len;

                    n = (n + 1) % 16;

                }

                if (n == 0) {

                    GCM_MUL(ctx);

                    mres = 0;

                } else {

                    ctx->mres = n;

                    return 0;

                }

# endif

            }

# if defined(STRICT_ALIGNMENT)

            if (((size_t)in | (size_t)out) % sizeof(size_t) != 0)

                break;

# endif

# if defined(GHASH)

            if (len >= 16 && mres) {

                GHASH(ctx, ctx->Xn, mres);

                mres = 0;

            }

#  if defined(GHASH_CHUNK)

            while (len >= GHASH_CHUNK) {

                size_t j = GHASH_CHUNK;

                while (j) {

                    size_t_aX *out_t = (size_t_aX *)out;

                    const size_t_aX *in_t = (const size_t_aX *)in;

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

                    ++ctr;

                    if (IS_LITTLE_ENDIAN)

#   ifdef BSWAP4

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

#   else

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

#   endif

                    else

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

                    for (i = 0; i < 16 / sizeof(size_t); ++i)

                        out_t[i] = in_t[i] ^ ctx->EKi.t[i];

                    out += 16;

                    in += 16;

                    j -= 16;

                }

                GHASH(ctx, out - GHASH_CHUNK, GHASH_CHUNK);

                len -= GHASH_CHUNK;

            }

#  endif

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

                size_t j = i;

                while (len >= 16) {

                    size_t_aX *out_t = (size_t_aX *)out;

                    const size_t_aX *in_t = (const size_t_aX *)in;

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

                    ++ctr;

                    if (IS_LITTLE_ENDIAN)

#  ifdef BSWAP4

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

#  else

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

#  endif

                    else

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

                    for (i = 0; i < 16 / sizeof(size_t); ++i)

                        out_t[i] = in_t[i] ^ ctx->EKi.t[i];

                    out += 16;

                    in += 16;

                    len -= 16;

                }

                GHASH(ctx, out - j, j);

            }

# else

            while (len >= 16) {

                size_t *out_t = (size_t *)out;

                const size_t *in_t = (const size_t *)in;

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

                ++ctr;

                if (IS_LITTLE_ENDIAN)

#  ifdef BSWAP4

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

#  else

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

#  endif

                else

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

                for (i = 0; i < 16 / sizeof(size_t); ++i)

                    ctx->Xi.t[i] ^= out_t[i] = in_t[i] ^ ctx->EKi.t[i];

                GCM_MUL(ctx);

                out += 16;

                in += 16;

                len -= 16;

            }

# endif

            if (len) {

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

                ++ctr;

                if (IS_LITTLE_ENDIAN)

# ifdef BSWAP4

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

# else

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

# endif

                else

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

# if defined(GHASH)

                while (len--) {

                    ctx->Xn[mres++] = out[n] = in[n] ^ ctx->EKi.c[n];

                    ++n;

                }

# else

                while (len--) {

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

                    ++n;

                }

                mres = n;

# endif

            }

            ctx->mres = mres;

            return 0;

        } while (0);

    }

#endif

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