libmicrohttpd2

HTTP server C library (MHD 2.x, alpha)
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sha512_256_int.c (29401B)


      1 /* SPDX-License-Identifier: LGPL-2.1-or-later OR (GPL-2.0-or-later WITH eCos-exception-2.0) */
      2 /*
      3   This file is part of GNU libmicrohttpd.
      4   Copyright (C) 2022-2024 Evgeny Grin (Karlson2k)
      5 
      6   GNU libmicrohttpd is free software; you can redistribute it and/or
      7   modify it under the terms of the GNU Lesser General Public
      8   License as published by the Free Software Foundation; either
      9   version 2.1 of the License, or (at your option) any later version.
     10 
     11   GNU libmicrohttpd is distributed in the hope that it will be useful,
     12   but WITHOUT ANY WARRANTY; without even the implied warranty of
     13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     14   Lesser General Public License for more details.
     15 
     16   Alternatively, you can redistribute GNU libmicrohttpd and/or
     17   modify it under the terms of the GNU General Public License as
     18   published by the Free Software Foundation; either version 2 of
     19   the License, or (at your option) any later version, together
     20   with the eCos exception, as follows:
     21 
     22     As a special exception, if other files instantiate templates or
     23     use macros or inline functions from this file, or you compile this
     24     file and link it with other works to produce a work based on this
     25     file, this file does not by itself cause the resulting work to be
     26     covered by the GNU General Public License. However the source code
     27     for this file must still be made available in accordance with
     28     section (3) of the GNU General Public License v2.
     29 
     30     This exception does not invalidate any other reasons why a work
     31     based on this file might be covered by the GNU General Public
     32     License.
     33 
     34   You should have received copies of the GNU Lesser General Public
     35   License and the GNU General Public License along with this library;
     36   if not, see <https://www.gnu.org/licenses/>.
     37 */
     38 
     39 /**
     40  * @file src/mhd2/sha512_256.c
     41  * @brief  Calculation of SHA-512/256 digest as defined in FIPS PUB 180-4 (2015)
     42  * @author Karlson2k (Evgeny Grin)
     43  */
     44 
     45 #include "mhd_sys_options.h"
     46 
     47 #include "sys_bool_type.h"
     48 
     49 #include <string.h>
     50 #include "mhd_bithelpers.h"
     51 #include "mhd_align.h"
     52 #include "mhd_assert.h"
     53 
     54 #include "sha512_256_int.h"
     55 
     56 MHD_INTERNAL MHD_FN_PAR_NONNULL_ALL_ void
     57 mhd_SHA512_256_init (struct mhd_Sha512_256CtxInt *ctx)
     58 {
     59   /* Initial hash values, see FIPS PUB 180-4 clause 5.3.6.2 */
     60   /* Values generated by "IV Generation Function" as described in
     61    * clause 5.3.6 */
     62   ctx->H[0] = UINT64_C (0x22312194FC2BF72C);
     63   ctx->H[1] = UINT64_C (0x9F555FA3C84C64C2);
     64   ctx->H[2] = UINT64_C (0x2393B86B6F53B151);
     65   ctx->H[3] = UINT64_C (0x963877195940EABD);
     66   ctx->H[4] = UINT64_C (0x96283EE2A88EFFE3);
     67   ctx->H[5] = UINT64_C (0xBE5E1E2553863992);
     68   ctx->H[6] = UINT64_C (0x2B0199FC2C85B8AA);
     69   ctx->H[7] = UINT64_C (0x0EB72DDC81C52CA2);
     70 
     71   /* Initialise number of bytes and high part of number of bits. */
     72   ctx->count = 0;
     73   ctx->count_bits_hi = 0;
     74 }
     75 
     76 
     77 mhd_DATA_TRUNCATION_RUNTIME_CHECK_DISABLE
     78 
     79 /**
     80  * Base of SHA-512/256 transformation.
     81  * Gets full 128 bytes block of data and updates hash values;
     82  * @param H     hash values
     83  * @param data  the data buffer with #mhd_SHA512_256_BLOCK_SIZE bytes block
     84  */
     85 static MHD_FN_PAR_NONNULL_ALL_ void
     86 sha512_256_transform (uint64_t H[mhd_SHA512_256_HASH_SIZE_WORDS],
     87                       const void *restrict data)
     88 {
     89   /* Working variables,
     90      see FIPS PUB 180-4 clause 6.7, 6.4. */
     91   uint64_t a = H[0];
     92   uint64_t b = H[1];
     93   uint64_t c = H[2];
     94   uint64_t d = H[3];
     95   uint64_t e = H[4];
     96   uint64_t f = H[5];
     97   uint64_t g = H[6];
     98   uint64_t h = H[7];
     99 
    100   /* Data buffer, used as a cyclic buffer.
    101      See FIPS PUB 180-4 clause 5.2.2, 6.7, 6.4. */
    102   uint64_t W[16];
    103 
    104 #ifndef mhd_GET_64BIT_BE_ALLOW_UNALIGNED
    105   if (0 != (((uintptr_t)data) % mhd_UINT64_ALIGN))
    106   { /* The input data is unaligned */
    107     /* Copy the unaligned input data to the aligned buffer */
    108     memcpy (W, data, sizeof(W));
    109     /* The W[] buffer itself will be used as the source of the data,
    110      * but the data will be reloaded in correct bytes order on
    111      * the next steps */
    112     data = (const void *)W;
    113   }
    114 #endif /* mhd_GET_64BIT_BE_ALLOW_UNALIGNED */
    115 
    116   /* 'Ch' and 'Maj' macro functions are defined with
    117      widely-used optimisation.
    118      See FIPS PUB 180-4 formulae 4.8, 4.9. */
    119 #define Ch(x, y, z)     ( (z) ^ ((x) & ((y) ^ (z))) )
    120 #define Maj(x, y, z)    ( ((x) & (y)) ^ ((z) & ((x) ^ (y))) )
    121   /* Unoptimized (original) versions: */
    122 /* #define Ch(x,y,z)  ( ( (x) & (y) ) ^ ( ~(x) & (z) ) )          */
    123 /* #define Maj(x,y,z) ( ((x) & (y)) ^ ((x) & (z)) ^ ((y) & (z)) ) */
    124 
    125   /* Four 'Sigma' macro functions.
    126      See FIPS PUB 180-4 formulae 4.10, 4.11, 4.12, 4.13. */
    127 #define SIG0(x)  \
    128         (mhd_ROTR64 ((x), 28) ^ mhd_ROTR64 ((x), 34) ^ mhd_ROTR64 ((x), 39) )
    129 #define SIG1(x)  \
    130         (mhd_ROTR64 ((x), 14) ^ mhd_ROTR64 ((x), 18) ^ mhd_ROTR64 ((x), 41) )
    131 #define sig0(x)  \
    132         (mhd_ROTR64 ((x), 1) ^ mhd_ROTR64 ((x), 8) ^ ((x) >> 7) )
    133 #define sig1(x)  \
    134         (mhd_ROTR64 ((x), 19) ^ mhd_ROTR64 ((x), 61) ^ ((x) >> 6) )
    135 
    136   /* One step of SHA-512/256 computation,
    137      see FIPS PUB 180-4 clause 6.4.2 step 3.
    138    * Note: this macro updates working variables in-place, without rotation.
    139    * Note: the first (vH += SIG1(vE) + Ch(vE,vF,vG) + kt + wt) equals T1 in
    140            FIPS PUB 180-4 clause 6.4.2 step 3.
    141            the second (vH += SIG0(vA) + Maj(vE,vF,vC) equals T1 + T2 in
    142            FIPS PUB 180-4 clause 6.4.2 step 3.
    143    * Note: 'wt' must be used exactly one time in this macro as it change other
    144            data as well every time when used. */
    145 #define SHA2STEP64(vA, vB, vC, vD, vE, vF, vG, vH, kt, wt) do {         \
    146         (vD) += ((vH) += SIG1 ((vE)) + Ch ((vE),(vF),(vG)) + (kt) + (wt));  \
    147         (vH) += SIG0 ((vA)) + Maj ((vA),(vB),(vC)); } while (0)
    148 
    149   /* Get value of W(t) from input data buffer for 0 <= t <= 15,
    150      See FIPS PUB 180-4 clause 6.2.
    151      Input data must be read in big-endian bytes order,
    152      see FIPS PUB 180-4 clause 3.1.2. */
    153 #define GET_W_FROM_DATA(buf, t) \
    154         mhd_GET_64BIT_BE (((const uint64_t*) (buf)) + (t))
    155 
    156   /* 'W' generation and assignment for 16 <= t <= 79.
    157      See FIPS PUB 180-4 clause 6.4.2.
    158      As only last 16 'W' are used in calculations, it is possible to
    159      use 16 elements array of W as a cyclic buffer.
    160    * Note: ((t-16) & 15) have same value as (t & 15) */
    161 #define Wgen(w, t) ( (w)[(t - 16) & 15] + sig1 ((w)[((t) - 2) & 15])  \
    162         + (w)[((t) - 7) & 15] + sig0 ((w)[((t) - 15) & 15]) )
    163 
    164 #ifndef MHD_FAVOR_SMALL_CODE
    165 
    166   /* Note: instead of using K constants as array, all K values are specified
    167            individually for each step, see FIPS PUB 180-4 clause 4.2.3 for
    168            K values. */
    169   /* Note: instead of reassigning all working variables on each step,
    170            variables are rotated for each step:
    171              SHA2STEP64(a, b, c, d, e, f, g, h, K[0], data[0]);
    172              SHA2STEP64(h, a, b, c, d, e, f, g, K[1], data[1]);
    173            so current 'vD' will be used as 'vE' on next step,
    174            current 'vH' will be used as 'vA' on next step. */
    175 #  if mhd_BYTE_ORDER == mhd_BIG_ENDIAN
    176   if ((const void *)W == data)
    177   {
    178     /* The input data is already in the cyclic data buffer W[] in correct bytes
    179        order. */
    180     SHA2STEP64 (a, b, c, d, e, f, g, h, UINT64_C (0x428a2f98d728ae22), W[0]);
    181     SHA2STEP64 (h, a, b, c, d, e, f, g, UINT64_C (0x7137449123ef65cd), W[1]);
    182     SHA2STEP64 (g, h, a, b, c, d, e, f, UINT64_C (0xb5c0fbcfec4d3b2f), W[2]);
    183     SHA2STEP64 (f, g, h, a, b, c, d, e, UINT64_C (0xe9b5dba58189dbbc), W[3]);
    184     SHA2STEP64 (e, f, g, h, a, b, c, d, UINT64_C (0x3956c25bf348b538), W[4]);
    185     SHA2STEP64 (d, e, f, g, h, a, b, c, UINT64_C (0x59f111f1b605d019), W[5]);
    186     SHA2STEP64 (c, d, e, f, g, h, a, b, UINT64_C (0x923f82a4af194f9b), W[6]);
    187     SHA2STEP64 (b, c, d, e, f, g, h, a, UINT64_C (0xab1c5ed5da6d8118), W[7]);
    188     SHA2STEP64 (a, b, c, d, e, f, g, h, UINT64_C (0xd807aa98a3030242), W[8]);
    189     SHA2STEP64 (h, a, b, c, d, e, f, g, UINT64_C (0x12835b0145706fbe), W[9]);
    190     SHA2STEP64 (g, h, a, b, c, d, e, f, UINT64_C (0x243185be4ee4b28c), W[10]);
    191     SHA2STEP64 (f, g, h, a, b, c, d, e, UINT64_C (0x550c7dc3d5ffb4e2), W[11]);
    192     SHA2STEP64 (e, f, g, h, a, b, c, d, UINT64_C (0x72be5d74f27b896f), W[12]);
    193     SHA2STEP64 (d, e, f, g, h, a, b, c, UINT64_C (0x80deb1fe3b1696b1), W[13]);
    194     SHA2STEP64 (c, d, e, f, g, h, a, b, UINT64_C (0x9bdc06a725c71235), W[14]);
    195     SHA2STEP64 (b, c, d, e, f, g, h, a, UINT64_C (0xc19bf174cf692694), W[15]);
    196   }
    197   else /* Combined with the next 'if' */
    198 #  endif /* mhd_BYTE_ORDER == mhd_BIG_ENDIAN */
    199   if (1)
    200   {
    201     /* During first 16 steps, before making any calculations on each step,
    202        the W element is read from the input data buffer as big-endian value and
    203        stored in the array of W elements. */
    204     SHA2STEP64 (a, b, c, d, e, f, g, h, UINT64_C (0x428a2f98d728ae22), \
    205                 W[0] = GET_W_FROM_DATA (data, 0));
    206     SHA2STEP64 (h, a, b, c, d, e, f, g, UINT64_C (0x7137449123ef65cd), \
    207                 W[1] = GET_W_FROM_DATA (data, 1));
    208     SHA2STEP64 (g, h, a, b, c, d, e, f, UINT64_C (0xb5c0fbcfec4d3b2f), \
    209                 W[2] = GET_W_FROM_DATA (data, 2));
    210     SHA2STEP64 (f, g, h, a, b, c, d, e, UINT64_C (0xe9b5dba58189dbbc), \
    211                 W[3] = GET_W_FROM_DATA (data, 3));
    212     SHA2STEP64 (e, f, g, h, a, b, c, d, UINT64_C (0x3956c25bf348b538), \
    213                 W[4] = GET_W_FROM_DATA (data, 4));
    214     SHA2STEP64 (d, e, f, g, h, a, b, c, UINT64_C (0x59f111f1b605d019), \
    215                 W[5] = GET_W_FROM_DATA (data, 5));
    216     SHA2STEP64 (c, d, e, f, g, h, a, b, UINT64_C (0x923f82a4af194f9b), \
    217                 W[6] = GET_W_FROM_DATA (data, 6));
    218     SHA2STEP64 (b, c, d, e, f, g, h, a, UINT64_C (0xab1c5ed5da6d8118), \
    219                 W[7] = GET_W_FROM_DATA (data, 7));
    220     SHA2STEP64 (a, b, c, d, e, f, g, h, UINT64_C (0xd807aa98a3030242), \
    221                 W[8] = GET_W_FROM_DATA (data, 8));
    222     SHA2STEP64 (h, a, b, c, d, e, f, g, UINT64_C (0x12835b0145706fbe), \
    223                 W[9] = GET_W_FROM_DATA (data, 9));
    224     SHA2STEP64 (g, h, a, b, c, d, e, f, UINT64_C (0x243185be4ee4b28c), \
    225                 W[10] = GET_W_FROM_DATA (data, 10));
    226     SHA2STEP64 (f, g, h, a, b, c, d, e, UINT64_C (0x550c7dc3d5ffb4e2), \
    227                 W[11] = GET_W_FROM_DATA (data, 11));
    228     SHA2STEP64 (e, f, g, h, a, b, c, d, UINT64_C (0x72be5d74f27b896f), \
    229                 W[12] = GET_W_FROM_DATA (data, 12));
    230     SHA2STEP64 (d, e, f, g, h, a, b, c, UINT64_C (0x80deb1fe3b1696b1), \
    231                 W[13] = GET_W_FROM_DATA (data, 13));
    232     SHA2STEP64 (c, d, e, f, g, h, a, b, UINT64_C (0x9bdc06a725c71235), \
    233                 W[14] = GET_W_FROM_DATA (data, 14));
    234     SHA2STEP64 (b, c, d, e, f, g, h, a, UINT64_C (0xc19bf174cf692694), \
    235                 W[15] = GET_W_FROM_DATA (data, 15));
    236   }
    237 
    238   /* During last 64 steps, before making any calculations on each step,
    239      current W element is generated from other W elements of the cyclic buffer
    240      and the generated value is stored back in the cyclic buffer. */
    241   /* Note: instead of using K constants as array, all K values are specified
    242      individually for each step, see FIPS PUB 180-4 clause 4.2.3 for
    243      K values. */
    244   SHA2STEP64 (a, b, c, d, e, f, g, h, UINT64_C (0xe49b69c19ef14ad2), \
    245               W[16 & 15] = Wgen (W, 16));
    246   SHA2STEP64 (h, a, b, c, d, e, f, g, UINT64_C (0xefbe4786384f25e3), \
    247               W[17 & 15] = Wgen (W, 17));
    248   SHA2STEP64 (g, h, a, b, c, d, e, f, UINT64_C (0x0fc19dc68b8cd5b5), \
    249               W[18 & 15] = Wgen (W, 18));
    250   SHA2STEP64 (f, g, h, a, b, c, d, e, UINT64_C (0x240ca1cc77ac9c65), \
    251               W[19 & 15] = Wgen (W, 19));
    252   SHA2STEP64 (e, f, g, h, a, b, c, d, UINT64_C (0x2de92c6f592b0275), \
    253               W[20 & 15] = Wgen (W, 20));
    254   SHA2STEP64 (d, e, f, g, h, a, b, c, UINT64_C (0x4a7484aa6ea6e483), \
    255               W[21 & 15] = Wgen (W, 21));
    256   SHA2STEP64 (c, d, e, f, g, h, a, b, UINT64_C (0x5cb0a9dcbd41fbd4), \
    257               W[22 & 15] = Wgen (W, 22));
    258   SHA2STEP64 (b, c, d, e, f, g, h, a, UINT64_C (0x76f988da831153b5), \
    259               W[23 & 15] = Wgen (W, 23));
    260   SHA2STEP64 (a, b, c, d, e, f, g, h, UINT64_C (0x983e5152ee66dfab), \
    261               W[24 & 15] = Wgen (W, 24));
    262   SHA2STEP64 (h, a, b, c, d, e, f, g, UINT64_C (0xa831c66d2db43210), \
    263               W[25 & 15] = Wgen (W, 25));
    264   SHA2STEP64 (g, h, a, b, c, d, e, f, UINT64_C (0xb00327c898fb213f), \
    265               W[26 & 15] = Wgen (W, 26));
    266   SHA2STEP64 (f, g, h, a, b, c, d, e, UINT64_C (0xbf597fc7beef0ee4), \
    267               W[27 & 15] = Wgen (W, 27));
    268   SHA2STEP64 (e, f, g, h, a, b, c, d, UINT64_C (0xc6e00bf33da88fc2), \
    269               W[28 & 15] = Wgen (W, 28));
    270   SHA2STEP64 (d, e, f, g, h, a, b, c, UINT64_C (0xd5a79147930aa725), \
    271               W[29 & 15] = Wgen (W, 29));
    272   SHA2STEP64 (c, d, e, f, g, h, a, b, UINT64_C (0x06ca6351e003826f), \
    273               W[30 & 15] = Wgen (W, 30));
    274   SHA2STEP64 (b, c, d, e, f, g, h, a, UINT64_C (0x142929670a0e6e70), \
    275               W[31 & 15] = Wgen (W, 31));
    276   SHA2STEP64 (a, b, c, d, e, f, g, h, UINT64_C (0x27b70a8546d22ffc), \
    277               W[32 & 15] = Wgen (W, 32));
    278   SHA2STEP64 (h, a, b, c, d, e, f, g, UINT64_C (0x2e1b21385c26c926), \
    279               W[33 & 15] = Wgen (W, 33));
    280   SHA2STEP64 (g, h, a, b, c, d, e, f, UINT64_C (0x4d2c6dfc5ac42aed), \
    281               W[34 & 15] = Wgen (W, 34));
    282   SHA2STEP64 (f, g, h, a, b, c, d, e, UINT64_C (0x53380d139d95b3df), \
    283               W[35 & 15] = Wgen (W, 35));
    284   SHA2STEP64 (e, f, g, h, a, b, c, d, UINT64_C (0x650a73548baf63de), \
    285               W[36 & 15] = Wgen (W, 36));
    286   SHA2STEP64 (d, e, f, g, h, a, b, c, UINT64_C (0x766a0abb3c77b2a8), \
    287               W[37 & 15] = Wgen (W, 37));
    288   SHA2STEP64 (c, d, e, f, g, h, a, b, UINT64_C (0x81c2c92e47edaee6), \
    289               W[38 & 15] = Wgen (W, 38));
    290   SHA2STEP64 (b, c, d, e, f, g, h, a, UINT64_C (0x92722c851482353b), \
    291               W[39 & 15] = Wgen (W, 39));
    292   SHA2STEP64 (a, b, c, d, e, f, g, h, UINT64_C (0xa2bfe8a14cf10364), \
    293               W[40 & 15] = Wgen (W, 40));
    294   SHA2STEP64 (h, a, b, c, d, e, f, g, UINT64_C (0xa81a664bbc423001), \
    295               W[41 & 15] = Wgen (W, 41));
    296   SHA2STEP64 (g, h, a, b, c, d, e, f, UINT64_C (0xc24b8b70d0f89791), \
    297               W[42 & 15] = Wgen (W, 42));
    298   SHA2STEP64 (f, g, h, a, b, c, d, e, UINT64_C (0xc76c51a30654be30), \
    299               W[43 & 15] = Wgen (W, 43));
    300   SHA2STEP64 (e, f, g, h, a, b, c, d, UINT64_C (0xd192e819d6ef5218), \
    301               W[44 & 15] = Wgen (W, 44));
    302   SHA2STEP64 (d, e, f, g, h, a, b, c, UINT64_C (0xd69906245565a910), \
    303               W[45 & 15] = Wgen (W, 45));
    304   SHA2STEP64 (c, d, e, f, g, h, a, b, UINT64_C (0xf40e35855771202a), \
    305               W[46 & 15] = Wgen (W, 46));
    306   SHA2STEP64 (b, c, d, e, f, g, h, a, UINT64_C (0x106aa07032bbd1b8), \
    307               W[47 & 15] = Wgen (W, 47));
    308   SHA2STEP64 (a, b, c, d, e, f, g, h, UINT64_C (0x19a4c116b8d2d0c8), \
    309               W[48 & 15] = Wgen (W, 48));
    310   SHA2STEP64 (h, a, b, c, d, e, f, g, UINT64_C (0x1e376c085141ab53), \
    311               W[49 & 15] = Wgen (W, 49));
    312   SHA2STEP64 (g, h, a, b, c, d, e, f, UINT64_C (0x2748774cdf8eeb99), \
    313               W[50 & 15] = Wgen (W, 50));
    314   SHA2STEP64 (f, g, h, a, b, c, d, e, UINT64_C (0x34b0bcb5e19b48a8), \
    315               W[51 & 15] = Wgen (W, 51));
    316   SHA2STEP64 (e, f, g, h, a, b, c, d, UINT64_C (0x391c0cb3c5c95a63), \
    317               W[52 & 15] = Wgen (W, 52));
    318   SHA2STEP64 (d, e, f, g, h, a, b, c, UINT64_C (0x4ed8aa4ae3418acb), \
    319               W[53 & 15] = Wgen (W, 53));
    320   SHA2STEP64 (c, d, e, f, g, h, a, b, UINT64_C (0x5b9cca4f7763e373), \
    321               W[54 & 15] = Wgen (W, 54));
    322   SHA2STEP64 (b, c, d, e, f, g, h, a, UINT64_C (0x682e6ff3d6b2b8a3), \
    323               W[55 & 15] = Wgen (W, 55));
    324   SHA2STEP64 (a, b, c, d, e, f, g, h, UINT64_C (0x748f82ee5defb2fc), \
    325               W[56 & 15] = Wgen (W, 56));
    326   SHA2STEP64 (h, a, b, c, d, e, f, g, UINT64_C (0x78a5636f43172f60), \
    327               W[57 & 15] = Wgen (W, 57));
    328   SHA2STEP64 (g, h, a, b, c, d, e, f, UINT64_C (0x84c87814a1f0ab72), \
    329               W[58 & 15] = Wgen (W, 58));
    330   SHA2STEP64 (f, g, h, a, b, c, d, e, UINT64_C (0x8cc702081a6439ec), \
    331               W[59 & 15] = Wgen (W, 59));
    332   SHA2STEP64 (e, f, g, h, a, b, c, d, UINT64_C (0x90befffa23631e28), \
    333               W[60 & 15] = Wgen (W, 60));
    334   SHA2STEP64 (d, e, f, g, h, a, b, c, UINT64_C (0xa4506cebde82bde9), \
    335               W[61 & 15] = Wgen (W, 61));
    336   SHA2STEP64 (c, d, e, f, g, h, a, b, UINT64_C (0xbef9a3f7b2c67915), \
    337               W[62 & 15] = Wgen (W, 62));
    338   SHA2STEP64 (b, c, d, e, f, g, h, a, UINT64_C (0xc67178f2e372532b), \
    339               W[63 & 15] = Wgen (W, 63));
    340   SHA2STEP64 (a, b, c, d, e, f, g, h, UINT64_C (0xca273eceea26619c), \
    341               W[64 & 15] = Wgen (W, 64));
    342   SHA2STEP64 (h, a, b, c, d, e, f, g, UINT64_C (0xd186b8c721c0c207), \
    343               W[65 & 15] = Wgen (W, 65));
    344   SHA2STEP64 (g, h, a, b, c, d, e, f, UINT64_C (0xeada7dd6cde0eb1e), \
    345               W[66 & 15] = Wgen (W, 66));
    346   SHA2STEP64 (f, g, h, a, b, c, d, e, UINT64_C (0xf57d4f7fee6ed178), \
    347               W[67 & 15] = Wgen (W, 67));
    348   SHA2STEP64 (e, f, g, h, a, b, c, d, UINT64_C (0x06f067aa72176fba), \
    349               W[68 & 15] = Wgen (W, 68));
    350   SHA2STEP64 (d, e, f, g, h, a, b, c, UINT64_C (0x0a637dc5a2c898a6), \
    351               W[69 & 15] = Wgen (W, 69));
    352   SHA2STEP64 (c, d, e, f, g, h, a, b, UINT64_C (0x113f9804bef90dae), \
    353               W[70 & 15] = Wgen (W, 70));
    354   SHA2STEP64 (b, c, d, e, f, g, h, a, UINT64_C (0x1b710b35131c471b), \
    355               W[71 & 15] = Wgen (W, 71));
    356   SHA2STEP64 (a, b, c, d, e, f, g, h, UINT64_C (0x28db77f523047d84), \
    357               W[72 & 15] = Wgen (W, 72));
    358   SHA2STEP64 (h, a, b, c, d, e, f, g, UINT64_C (0x32caab7b40c72493), \
    359               W[73 & 15] = Wgen (W, 73));
    360   SHA2STEP64 (g, h, a, b, c, d, e, f, UINT64_C (0x3c9ebe0a15c9bebc), \
    361               W[74 & 15] = Wgen (W, 74));
    362   SHA2STEP64 (f, g, h, a, b, c, d, e, UINT64_C (0x431d67c49c100d4c), \
    363               W[75 & 15] = Wgen (W, 75));
    364   SHA2STEP64 (e, f, g, h, a, b, c, d, UINT64_C (0x4cc5d4becb3e42b6), \
    365               W[76 & 15] = Wgen (W, 76));
    366   SHA2STEP64 (d, e, f, g, h, a, b, c, UINT64_C (0x597f299cfc657e2a), \
    367               W[77 & 15] = Wgen (W, 77));
    368   SHA2STEP64 (c, d, e, f, g, h, a, b, UINT64_C (0x5fcb6fab3ad6faec), \
    369               W[78 & 15] = Wgen (W, 78));
    370   SHA2STEP64 (b, c, d, e, f, g, h, a, UINT64_C (0x6c44198c4a475817), \
    371               W[79 & 15] = Wgen (W, 79));
    372 #else  /* MHD_FAVOR_SMALL_CODE */
    373   if (1)
    374   {
    375     unsigned int t;
    376     /* K constants array.
    377        See FIPS PUB 180-4 clause 4.2.3 for K values. */
    378     static const uint64_t K[80] =
    379     { UINT64_C (0x428a2f98d728ae22), UINT64_C (0x7137449123ef65cd),
    380       UINT64_C (0xb5c0fbcfec4d3b2f), UINT64_C (0xe9b5dba58189dbbc),
    381       UINT64_C (0x3956c25bf348b538), UINT64_C (0x59f111f1b605d019),
    382       UINT64_C (0x923f82a4af194f9b), UINT64_C (0xab1c5ed5da6d8118),
    383       UINT64_C (0xd807aa98a3030242), UINT64_C (0x12835b0145706fbe),
    384       UINT64_C (0x243185be4ee4b28c), UINT64_C (0x550c7dc3d5ffb4e2),
    385       UINT64_C (0x72be5d74f27b896f), UINT64_C (0x80deb1fe3b1696b1),
    386       UINT64_C (0x9bdc06a725c71235), UINT64_C (0xc19bf174cf692694),
    387       UINT64_C (0xe49b69c19ef14ad2), UINT64_C (0xefbe4786384f25e3),
    388       UINT64_C (0x0fc19dc68b8cd5b5), UINT64_C (0x240ca1cc77ac9c65),
    389       UINT64_C (0x2de92c6f592b0275), UINT64_C (0x4a7484aa6ea6e483),
    390       UINT64_C (0x5cb0a9dcbd41fbd4), UINT64_C (0x76f988da831153b5),
    391       UINT64_C (0x983e5152ee66dfab), UINT64_C (0xa831c66d2db43210),
    392       UINT64_C (0xb00327c898fb213f), UINT64_C (0xbf597fc7beef0ee4),
    393       UINT64_C (0xc6e00bf33da88fc2), UINT64_C (0xd5a79147930aa725),
    394       UINT64_C (0x06ca6351e003826f), UINT64_C (0x142929670a0e6e70),
    395       UINT64_C (0x27b70a8546d22ffc), UINT64_C (0x2e1b21385c26c926),
    396       UINT64_C (0x4d2c6dfc5ac42aed), UINT64_C (0x53380d139d95b3df),
    397       UINT64_C (0x650a73548baf63de), UINT64_C (0x766a0abb3c77b2a8),
    398       UINT64_C (0x81c2c92e47edaee6), UINT64_C (0x92722c851482353b),
    399       UINT64_C (0xa2bfe8a14cf10364), UINT64_C (0xa81a664bbc423001),
    400       UINT64_C (0xc24b8b70d0f89791), UINT64_C (0xc76c51a30654be30),
    401       UINT64_C (0xd192e819d6ef5218), UINT64_C (0xd69906245565a910),
    402       UINT64_C (0xf40e35855771202a), UINT64_C (0x106aa07032bbd1b8),
    403       UINT64_C (0x19a4c116b8d2d0c8), UINT64_C (0x1e376c085141ab53),
    404       UINT64_C (0x2748774cdf8eeb99), UINT64_C (0x34b0bcb5e19b48a8),
    405       UINT64_C (0x391c0cb3c5c95a63), UINT64_C (0x4ed8aa4ae3418acb),
    406       UINT64_C (0x5b9cca4f7763e373), UINT64_C (0x682e6ff3d6b2b8a3),
    407       UINT64_C (0x748f82ee5defb2fc), UINT64_C (0x78a5636f43172f60),
    408       UINT64_C (0x84c87814a1f0ab72), UINT64_C (0x8cc702081a6439ec),
    409       UINT64_C (0x90befffa23631e28), UINT64_C (0xa4506cebde82bde9),
    410       UINT64_C (0xbef9a3f7b2c67915), UINT64_C (0xc67178f2e372532b),
    411       UINT64_C (0xca273eceea26619c), UINT64_C (0xd186b8c721c0c207),
    412       UINT64_C (0xeada7dd6cde0eb1e), UINT64_C (0xf57d4f7fee6ed178),
    413       UINT64_C (0x06f067aa72176fba), UINT64_C (0x0a637dc5a2c898a6),
    414       UINT64_C (0x113f9804bef90dae), UINT64_C (0x1b710b35131c471b),
    415       UINT64_C (0x28db77f523047d84), UINT64_C (0x32caab7b40c72493),
    416       UINT64_C (0x3c9ebe0a15c9bebc), UINT64_C (0x431d67c49c100d4c),
    417       UINT64_C (0x4cc5d4becb3e42b6), UINT64_C (0x597f299cfc657e2a),
    418       UINT64_C (0x5fcb6fab3ad6faec), UINT64_C (0x6c44198c4a475817)};
    419 
    420     /* One step of SHA-512/256 computation with working variables rotation,
    421        see FIPS PUB 180-4 clause 6.4.2 step 3.
    422      * Note: this version of macro reassign all working variable on
    423              each step. */
    424 #  define SHA2STEP64RV(vA, vB, vC, vD, vE, vF, vG, vH, kt, wt) \
    425           do {             \
    426             uint64_t tmp_h_ = (vH);                                           \
    427             SHA2STEP64 ((vA),(vB),(vC),(vD),(vE),(vF),(vG),tmp_h_,(kt),(wt)); \
    428             (vH) = (vG);   \
    429             (vG) = (vF);   \
    430             (vF) = (vE);   \
    431             (vE) = (vD);   \
    432             (vD) = (vC);   \
    433             (vC) = (vB);   \
    434             (vB) = (vA);   \
    435             (vA) = tmp_h_; \
    436           } while (0)
    437 
    438     /* During first 16 steps, before making any calculations on each step,
    439        the W element is read from the input data buffer as big-endian value and
    440        stored in the array of W elements. */
    441     for (t = 0; t < 16; ++t)
    442     {
    443       SHA2STEP64RV (a, b, c, d, e, f, g, h, K[t], \
    444                     W[t] = GET_W_FROM_DATA (data, t));
    445     }
    446     /* During last 64 steps, before making any calculations on each step,
    447        current W element is generated from other W elements of the cyclic buffer
    448        and the generated value is stored back in the cyclic buffer. */
    449     for (t = 16; t < 80; ++t)
    450     {
    451       SHA2STEP64RV (a, b, c, d, e, f, g, h, K[t], \
    452                     W[t & 15] = Wgen (W, t));
    453     }
    454   }
    455 #endif /* MHD_FAVOR_SMALL_CODE */
    456 
    457   /* Compute and store the intermediate hash.
    458      See FIPS PUB 180-4 clause 6.4.2 step 4. */
    459   H[0] += a;
    460   H[1] += b;
    461   H[2] += c;
    462   H[3] += d;
    463   H[4] += e;
    464   H[5] += f;
    465   H[6] += g;
    466   H[7] += h;
    467 }
    468 
    469 
    470 MHD_INTERNAL MHD_FN_PAR_NONNULL_ALL_
    471 MHD_FN_PAR_IN_SIZE_ (3, 2) void
    472 mhd_SHA512_256_update (struct mhd_Sha512_256CtxInt *restrict ctx,
    473                        size_t size,
    474                        const uint8_t *restrict data)
    475 {
    476   unsigned int bytes_have; /**< Number of bytes in the context buffer */
    477   uint64_t count_hi; /**< The high part to be moved to another variable */
    478 
    479   mhd_assert (0 != size);
    480 
    481   /* Note: (count & (mhd_SHA512_256_BLOCK_SIZE-1))
    482            equals (count % mhd_SHA512_256_BLOCK_SIZE) for this block size. */
    483   bytes_have = (unsigned int)(ctx->count & (mhd_SHA512_256_BLOCK_SIZE - 1));
    484   ctx->count += size;
    485 #if SIZEOF_SIZE_T > 7
    486   if (size > ctx->count)
    487     ctx->count_bits_hi += 1U << 3; /* Value wrap */
    488 #endif /* SIZEOF_SIZE_T > 7 */
    489   count_hi = ctx->count >> 61;
    490   if (0 != count_hi)
    491   {
    492     ctx->count_bits_hi += count_hi;
    493     ctx->count &= UINT64_C (0x1FFFFFFFFFFFFFFF);
    494   }
    495 
    496   if (0 != bytes_have)
    497   {
    498     unsigned int bytes_left = mhd_SHA512_256_BLOCK_SIZE - bytes_have;
    499     if (size >= bytes_left)
    500     {     /* Combine new data with data in the buffer and
    501              process the full block. */
    502       memcpy (((uint8_t *)ctx->buffer) + bytes_have,
    503               data,
    504               bytes_left);
    505       data += bytes_left;
    506       size -= bytes_left;
    507       sha512_256_transform (ctx->H, ctx->buffer);
    508       bytes_have = 0;
    509     }
    510   }
    511 
    512   while (mhd_SHA512_256_BLOCK_SIZE <= size)
    513   {   /* Process any full blocks of new data directly,
    514          without copying to the buffer. */
    515     sha512_256_transform (ctx->H, data);
    516     data += mhd_SHA512_256_BLOCK_SIZE;
    517     size -= mhd_SHA512_256_BLOCK_SIZE;
    518   }
    519 
    520   if (0 != size)
    521   {   /* Copy incomplete block of new data (if any)
    522          to the buffer. */
    523     memcpy (((uint8_t *)ctx->buffer) + bytes_have, data, size);
    524   }
    525 }
    526 
    527 
    528 /**
    529  * Size of "length" insertion in bits.
    530  * See FIPS PUB 180-4 clause 5.1.2.
    531  */
    532 #define SHA512_256_SIZE_OF_LEN_ADD_BITS 128
    533 
    534 /**
    535  * Size of "length" insertion in bytes.
    536  */
    537 #define SHA512_256_SIZE_OF_LEN_ADD (SHA512_256_SIZE_OF_LEN_ADD_BITS / 8)
    538 
    539 MHD_INTERNAL MHD_FN_PAR_NONNULL_ALL_ void
    540 mhd_SHA512_256_finish (struct mhd_Sha512_256CtxInt *restrict ctx,
    541                        uint8_t digest[mhd_SHA512_256_DIGEST_SIZE])
    542 {
    543   uint64_t num_bits;   /**< Number of processed bits */
    544   unsigned int bytes_have; /**< Number of bytes in the context buffer */
    545 
    546   /* Memorise the number of processed bits.
    547      The padding and other data added here during the postprocessing must
    548      not change the amount of hashed data. */
    549   num_bits = ctx->count << 3;
    550 
    551   /* Note: (count & (mhd_SHA512_256_BLOCK_SIZE-1))
    552            equals (count % mhd_SHA512_256_BLOCK_SIZE) for this block size. */
    553   bytes_have = (unsigned int)(ctx->count & (mhd_SHA512_256_BLOCK_SIZE - 1));
    554 
    555   /* Input data must be padded with a single bit "1", then with zeros and
    556      the finally the length of data in bits must be added as the final bytes
    557      of the last block.
    558      See FIPS PUB 180-4 clause 5.1.2. */
    559 
    560   /* Data is always processed in form of bytes (not by individual bits),
    561      therefore position of the first padding bit in byte is always
    562      predefined (0x80). */
    563   /* Buffer always have space for one byte at least (as full buffers are
    564      processed immediately). */
    565   ((uint8_t *)ctx->buffer)[bytes_have++] = 0x80;
    566 
    567   if (mhd_SHA512_256_BLOCK_SIZE - bytes_have < SHA512_256_SIZE_OF_LEN_ADD)
    568   {   /* No space in the current block to put the total length of message.
    569          Pad the current block with zeros and process it. */
    570     if (bytes_have < mhd_SHA512_256_BLOCK_SIZE)
    571       memset (((uint8_t *)ctx->buffer) + bytes_have, 0,
    572               mhd_SHA512_256_BLOCK_SIZE - bytes_have);
    573     /* Process the full block. */
    574     sha512_256_transform (ctx->H, ctx->buffer);
    575     /* Start the new block. */
    576     bytes_have = 0;
    577   }
    578 
    579   /* Pad the rest of the buffer with zeros. */
    580   memset (((uint8_t *)ctx->buffer) + bytes_have, 0,
    581           mhd_SHA512_256_BLOCK_SIZE - SHA512_256_SIZE_OF_LEN_ADD - bytes_have);
    582   /* Put high part of number of bits in processed message and then lower
    583      part of number of bits as big-endian values.
    584      See FIPS PUB 180-4 clause 5.1.2. */
    585   /* Note: the target location is predefined and buffer is always aligned */
    586   mhd_PUT_64BIT_BE (ctx->buffer + mhd_SHA512_256_BLOCK_SIZE_WORDS - 2,
    587                     ctx->count_bits_hi);
    588   mhd_PUT_64BIT_BE (ctx->buffer + mhd_SHA512_256_BLOCK_SIZE_WORDS - 1,
    589                     num_bits);
    590   /* Process the full final block. */
    591   sha512_256_transform (ctx->H, ctx->buffer);
    592 
    593   /* Put in BE mode the leftmost part of the hash as the final digest.
    594      See FIPS PUB 180-4 clause 6.7. */
    595   if (1)
    596   {
    597     bool use_tmp_buf_to_align_result;
    598 
    599 #if defined(mhd_PUT_64BIT_BE_UNALIGNED)
    600     use_tmp_buf_to_align_result = false;
    601 #elif defined(MHD_FAVOR_SMALL_CODE)
    602     use_tmp_buf_to_align_result = true; /* smaller code: eliminated branch below */
    603 #else
    604     use_tmp_buf_to_align_result =
    605       (0 != ((uintptr_t)digest) % mhd_UINT64_ALIGN);
    606 #endif
    607     if (use_tmp_buf_to_align_result)
    608     {
    609       /* If storing of the final result requires aligned address and
    610          the destination address is not aligned or compact code is used,
    611          store the final digest in aligned temporary buffer first, then
    612          copy it to the destination. */
    613       uint64_t alig_dgst[mhd_SHA512_256_DIGEST_SIZE_WORDS];
    614       mhd_PUT_64BIT_BE (alig_dgst + 0, ctx->H[0]);
    615       mhd_PUT_64BIT_BE (alig_dgst + 1, ctx->H[1]);
    616       mhd_PUT_64BIT_BE (alig_dgst + 2, ctx->H[2]);
    617       mhd_PUT_64BIT_BE (alig_dgst + 3, ctx->H[3]);
    618       /* Copy result to the unaligned destination address */
    619       memcpy (digest, alig_dgst, mhd_SHA512_256_DIGEST_SIZE);
    620     }
    621     else
    622     {
    623       /* Use cast to (void*) here to mute compiler alignment warnings.
    624        * Compilers are not smart enough to see that alignment has been checked. */
    625       mhd_PUT_64BIT_BE ((void *)(digest + 0 * mhd_SHA512_256_BYTES_IN_WORD), \
    626                         ctx->H[0]);
    627       mhd_PUT_64BIT_BE ((void *)(digest + 1 * mhd_SHA512_256_BYTES_IN_WORD), \
    628                         ctx->H[1]);
    629       mhd_PUT_64BIT_BE ((void *)(digest + 2 * mhd_SHA512_256_BYTES_IN_WORD), \
    630                         ctx->H[2]);
    631       mhd_PUT_64BIT_BE ((void *)(digest + 3 * mhd_SHA512_256_BYTES_IN_WORD), \
    632                         ctx->H[3]);
    633     }
    634   }
    635 
    636   /* Erase potentially sensitive data. */
    637   memset (ctx, 0, sizeof(struct mhd_Sha512_256CtxInt));
    638 }
    639 
    640 
    641 mhd_DATA_TRUNCATION_RUNTIME_CHECK_RESTORE