/* sha512.c - Functions to compute SHA512 and SHA384 message digest of files or
   memory blocks according to the NIST specification FIPS-180-2.

   Copyright (C) 2005, 2006 Free Software Foundation, Inc.

   This program is free software; you can redistribute it and/or modify it
   under the terms of the GNU General Public License as published by the
   Free Software Foundation; either version 2, or (at your option) any
   later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software Foundation,
   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */

/* Written by David Madore, considerably copypasting from
   Scott G. Miller's sha1.c
*/

/* This file is taken from coreutils-6.2 (lib/sha512.c) and adapted for dibbler
 * by Michal Kowalczuk <michal@kowalczuk.eu> */


#include "sha512.h"

#include <stddef.h>
#include <string.h>

#if USE_UNLOCKED_IO
# include "unlocked-io.h"
#endif

#ifdef WORDS_BIGENDIAN
# define SWAP(n) (n)
#else
# define SWAP(n) \
    (((n) << 56) | (((n) & 0xff00) << 40) | (((n) & 0xff0000UL) << 24) \
     | (((n) & 0xff000000UL) << 8) | (((n) >> 8) & 0xff000000UL) \
     | (((n) >> 24) & 0xff0000UL) | (((n) >> 40) & 0xff00UL) | ((n) >> 56))
#endif

#define BLOCKSIZE 4096
#if BLOCKSIZE % 128 != 0
# error "invalid BLOCKSIZE"
#endif

/* This array contains the bytes used to pad the buffer to the next
   128-byte boundary.  */
static const unsigned char fillbuf[128] = { 0x80, 0 /* , 0, 0, ...  */ };


/*
  Takes a pointer to a 512 bit block of data (eight 64 bit ints) and
  intializes it to the start constants of the SHA512 algorithm.  This
  must be called before using hash in the call to sha512_hash
*/
void
sha512_init_ctx (struct sha512_ctx *ctx)
{
  ctx->state[0] = 0x6a09e667f3bcc908ULL;
  ctx->state[1] = 0xbb67ae8584caa73bULL;
  ctx->state[2] = 0x3c6ef372fe94f82bULL;
  ctx->state[3] = 0xa54ff53a5f1d36f1ULL;
  ctx->state[4] = 0x510e527fade682d1ULL;
  ctx->state[5] = 0x9b05688c2b3e6c1fULL;
  ctx->state[6] = 0x1f83d9abfb41bd6bULL;
  ctx->state[7] = 0x5be0cd19137e2179ULL;

  ctx->total[0] = ctx->total[1] = 0;
  ctx->buflen = 0;
}

void
sha384_init_ctx (struct sha512_ctx *ctx)
{
  ctx->state[0] = 0xcbbb9d5dc1059ed8ULL;
  ctx->state[1] = 0x629a292a367cd507ULL;
  ctx->state[2] = 0x9159015a3070dd17ULL;
  ctx->state[3] = 0x152fecd8f70e5939ULL;
  ctx->state[4] = 0x67332667ffc00b31ULL;
  ctx->state[5] = 0x8eb44a8768581511ULL;
  ctx->state[6] = 0xdb0c2e0d64f98fa7ULL;
  ctx->state[7] = 0x47b5481dbefa4fa4ULL;

  ctx->total[0] = ctx->total[1] = 0;
  ctx->buflen = 0;
}

/* Put result from CTX in first 64 bytes following RESBUF.  The result
   must be in little endian byte order.

   IMPORTANT: On some systems it is required that RESBUF is correctly
   aligned for a 64-bit value.  */
void *
sha512_read_ctx (const struct sha512_ctx *ctx, void *resbuf)
{
  int i;

  for (i = 0; i < 8; i++)
    ((uint64_t *) resbuf)[i] = SWAP (ctx->state[i]);

  return resbuf;
}

void *
sha384_read_ctx (const struct sha512_ctx *ctx, void *resbuf)
{
  int i;

  for (i = 0; i < 6; i++)
    ((uint64_t *) resbuf)[i] = SWAP (ctx->state[i]);

  return resbuf;
}

/* Process the remaining bytes in the internal buffer and the usual
   prolog according to the standard and write the result to RESBUF.

   IMPORTANT: On some systems it is required that RESBUF is correctly
   aligned for a 64-bit value.  */
static void
sha512_conclude_ctx (struct sha512_ctx *ctx)
{
  /* Take yet unprocessed bytes into account.  */
  uint64_t bytes = ctx->buflen;
  size_t size = (bytes < 112) ? 128 / 8 : 128 * 2 / 8;

  /* Now count remaining bytes.  */
  ctx->total[0] += bytes;
  if (ctx->total[0] < bytes)
    ++ctx->total[1];

  /* Put the 64-bit file length in *bits* at the end of the buffer.  */
  ctx->buffer[size - 2] = SWAP ((ctx->total[1] << 3) | (ctx->total[0] >> 61));
  ctx->buffer[size - 1] = SWAP (ctx->total[0] << 3);

  memcpy (&((char *) ctx->buffer)[bytes], fillbuf, (size - 2) * 8 - bytes);

  /* Process last bytes.  */
  sha512_process_block (ctx->buffer, size * 8, ctx);
}

void *
sha512_finish_ctx (struct sha512_ctx *ctx, void *resbuf)
{
  sha512_conclude_ctx (ctx);
  return sha512_read_ctx (ctx, resbuf);
}

void *
sha384_finish_ctx (struct sha512_ctx *ctx, void *resbuf)
{
  sha512_conclude_ctx (ctx);
  return sha384_read_ctx (ctx, resbuf);
}

void
sha512_process_bytes (const void *buffer, size_t len, struct sha512_ctx *ctx)
{
  /* When we already have some bits in our internal buffer concatenate
     both inputs first.  */
  if (ctx->buflen != 0)
    {
      size_t left_over = ctx->buflen;
      size_t add = 256 - left_over > len ? len : 256 - left_over;

      memcpy (&((char *) ctx->buffer)[left_over], buffer, add);
      ctx->buflen += add;

      if (ctx->buflen > 128)
	{
	  sha512_process_block (ctx->buffer, ctx->buflen & ~63, ctx);

	  ctx->buflen &= 127;
	  /* The regions in the following copy operation cannot overlap.  */
	  memcpy (ctx->buffer,
		  &((char *) ctx->buffer)[(left_over + add) & ~127],
		  ctx->buflen);
	}

      buffer = (const char *) buffer + add;
      len -= add;
    }

  /* Process available complete blocks.  */
  if (len >= 128)
    {
#if !_STRING_ARCH_unaligned
# define alignof(type) offsetof (struct { char c; type x; }, x)
# define UNALIGNED_P(p) (((size_t) p) % alignof (uint64_t) != 0)
      if (UNALIGNED_P (buffer))
	while (len > 128)
	  {
	    sha512_process_block (memcpy (ctx->buffer, buffer, 128), 128, ctx);
	    buffer = (const char *) buffer + 128;
	    len -= 128;
	  }
      else
#endif
	{
	  sha512_process_block (buffer, len & ~127, ctx);
	  buffer = (const char *) buffer + (len & ~127);
	  len &= 127;
	}
    }

  /* Move remaining bytes in internal buffer.  */
  if (len > 0)
    {
      size_t left_over = ctx->buflen;

      memcpy (&((char *) ctx->buffer)[left_over], buffer, len);
      left_over += len;
      if (left_over >= 128)
	{
	  sha512_process_block (ctx->buffer, 128, ctx);
	  left_over -= 128;
	  memcpy (ctx->buffer, &ctx->buffer[16], left_over);
	}
      ctx->buflen = left_over;
    }
}

/* --- Code below is the primary difference between sha1.c and sha512.c --- */

/* SHA512 round constants */
#define K(I) sha512_round_constants[I]
static const uint64_t sha512_round_constants[80] = {
 0x428a2f98d728ae22ULL, 0x7137449123ef65cdULL, 0xb5c0fbcfec4d3b2fULL, 0xe9b5dba58189dbbcULL, 0x3956c25bf348b538ULL, 0x59f111f1b605d019ULL, 0x923f82a4af194f9bULL, 0xab1c5ed5da6d8118ULL,
 0xd807aa98a3030242ULL, 0x12835b0145706fbeULL, 0x243185be4ee4b28cULL, 0x550c7dc3d5ffb4e2ULL, 0x72be5d74f27b896fULL, 0x80deb1fe3b1696b1ULL, 0x9bdc06a725c71235ULL, 0xc19bf174cf692694ULL,
 0xe49b69c19ef14ad2ULL, 0xefbe4786384f25e3ULL, 0x0fc19dc68b8cd5b5ULL, 0x240ca1cc77ac9c65ULL, 0x2de92c6f592b0275ULL, 0x4a7484aa6ea6e483ULL, 0x5cb0a9dcbd41fbd4ULL, 0x76f988da831153b5ULL,
 0x983e5152ee66dfabULL, 0xa831c66d2db43210ULL, 0xb00327c898fb213fULL, 0xbf597fc7beef0ee4ULL, 0xc6e00bf33da88fc2ULL, 0xd5a79147930aa725ULL, 0x06ca6351e003826fULL, 0x142929670a0e6e70ULL,
 0x27b70a8546d22ffcULL, 0x2e1b21385c26c926ULL, 0x4d2c6dfc5ac42aedULL, 0x53380d139d95b3dfULL, 0x650a73548baf63deULL, 0x766a0abb3c77b2a8ULL, 0x81c2c92e47edaee6ULL, 0x92722c851482353bULL,
 0xa2bfe8a14cf10364ULL, 0xa81a664bbc423001ULL, 0xc24b8b70d0f89791ULL, 0xc76c51a30654be30ULL, 0xd192e819d6ef5218ULL, 0xd69906245565a910ULL, 0xf40e35855771202aULL, 0x106aa07032bbd1b8ULL,
 0x19a4c116b8d2d0c8ULL, 0x1e376c085141ab53ULL, 0x2748774cdf8eeb99ULL, 0x34b0bcb5e19b48a8ULL, 0x391c0cb3c5c95a63ULL, 0x4ed8aa4ae3418acbULL, 0x5b9cca4f7763e373ULL, 0x682e6ff3d6b2b8a3ULL,
 0x748f82ee5defb2fcULL, 0x78a5636f43172f60ULL, 0x84c87814a1f0ab72ULL, 0x8cc702081a6439ecULL, 0x90befffa23631e28ULL, 0xa4506cebde82bde9ULL, 0xbef9a3f7b2c67915ULL, 0xc67178f2e372532bULL,
 0xca273eceea26619cULL, 0xd186b8c721c0c207ULL, 0xeada7dd6cde0eb1eULL, 0xf57d4f7fee6ed178ULL, 0x06f067aa72176fbaULL, 0x0a637dc5a2c898a6ULL, 0x113f9804bef90daeULL, 0x1b710b35131c471bULL,
 0x28db77f523047d84ULL, 0x32caab7b40c72493ULL, 0x3c9ebe0a15c9bebcULL, 0x431d67c49c100d4cULL, 0x4cc5d4becb3e42b6ULL, 0x597f299cfc657e2aULL, 0x5fcb6fab3ad6faecULL, 0x6c44198c4a475817ULL,
};

/* Round functions.  */
#define F2(A,B,C) ( ( A & B ) | ( C & ( A | B ) ) )
#define F1(E,F,G) ( G ^ ( E & ( F ^ G ) ) )

/* Process LEN bytes of BUFFER, accumulating context into CTX.
   It is assumed that LEN % 128 == 0.
   Most of this code comes from GnuPG's cipher/sha1.c.  */

void
sha512_process_block (const void *buffer, size_t len, struct sha512_ctx *ctx)
{
  const uint64_t *words = buffer;
  size_t nwords = len / sizeof (uint64_t);
  const uint64_t *endp = words + nwords;
  uint64_t x[16];
  uint64_t a = ctx->state[0];
  uint64_t b = ctx->state[1];
  uint64_t c = ctx->state[2];
  uint64_t d = ctx->state[3];
  uint64_t e = ctx->state[4];
  uint64_t f = ctx->state[5];
  uint64_t g = ctx->state[6];
  uint64_t h = ctx->state[7];

  /* First increment the byte count.  FIPS PUB 180-2 specifies the possible
     length of the file up to 2^128 bits.  Here we only compute the
     number of bytes.  Do a double word increment.  */
  ctx->total[0] += len;
  if (ctx->total[0] < len)
    ++ctx->total[1];

#define S0(x) (rol64(x,63)^rol64(x,56)^(x>>7))
#define S1(x) (rol64(x,45)^rol64(x,3)^(x>>6))
#define SS0(x) (rol64(x,36)^rol64(x,30)^rol64(x,25))
#define SS1(x) (rol64(x,50)^rol64(x,46)^rol64(x,23))

#define M(I) ( tm =   S1(x[(I-2)&0x0f]) + x[(I-7)&0x0f] \
		    + S0(x[(I-15)&0x0f]) + x[I&0x0f]    \
	       , x[I&0x0f] = tm )

#define R(A,B,C,D,E,F,G,H,K,M)  do { t0 = SS0(A) + F2(A,B,C); \
                                     t1 = H + SS1(E)  \
                                      + F1(E,F,G)     \
				      + K	      \
				      + M;	      \
				     D += t1;  H = t0 + t1; \
			       } while(0)

  while (words < endp)
    {
      uint64_t tm;
      uint64_t t0, t1;
      int t;
      /* FIXME: see sha1.c for a better implementation.  */
      for (t = 0; t < 16; t++)
	{
	  x[t] = SWAP (*words);
	  words++;
	}

      R( a, b, c, d, e, f, g, h, K( 0), x[ 0] );
      R( h, a, b, c, d, e, f, g, K( 1), x[ 1] );
      R( g, h, a, b, c, d, e, f, K( 2), x[ 2] );
      R( f, g, h, a, b, c, d, e, K( 3), x[ 3] );
      R( e, f, g, h, a, b, c, d, K( 4), x[ 4] );
      R( d, e, f, g, h, a, b, c, K( 5), x[ 5] );
      R( c, d, e, f, g, h, a, b, K( 6), x[ 6] );
      R( b, c, d, e, f, g, h, a, K( 7), x[ 7] );
      R( a, b, c, d, e, f, g, h, K( 8), x[ 8] );
      R( h, a, b, c, d, e, f, g, K( 9), x[ 9] );
      R( g, h, a, b, c, d, e, f, K(10), x[10] );
      R( f, g, h, a, b, c, d, e, K(11), x[11] );
      R( e, f, g, h, a, b, c, d, K(12), x[12] );
      R( d, e, f, g, h, a, b, c, K(13), x[13] );
      R( c, d, e, f, g, h, a, b, K(14), x[14] );
      R( b, c, d, e, f, g, h, a, K(15), x[15] );
      R( a, b, c, d, e, f, g, h, K(16), M(16) );
      R( h, a, b, c, d, e, f, g, K(17), M(17) );
      R( g, h, a, b, c, d, e, f, K(18), M(18) );
      R( f, g, h, a, b, c, d, e, K(19), M(19) );
      R( e, f, g, h, a, b, c, d, K(20), M(20) );
      R( d, e, f, g, h, a, b, c, K(21), M(21) );
      R( c, d, e, f, g, h, a, b, K(22), M(22) );
      R( b, c, d, e, f, g, h, a, K(23), M(23) );
      R( a, b, c, d, e, f, g, h, K(24), M(24) );
      R( h, a, b, c, d, e, f, g, K(25), M(25) );
      R( g, h, a, b, c, d, e, f, K(26), M(26) );
      R( f, g, h, a, b, c, d, e, K(27), M(27) );
      R( e, f, g, h, a, b, c, d, K(28), M(28) );
      R( d, e, f, g, h, a, b, c, K(29), M(29) );
      R( c, d, e, f, g, h, a, b, K(30), M(30) );
      R( b, c, d, e, f, g, h, a, K(31), M(31) );
      R( a, b, c, d, e, f, g, h, K(32), M(32) );
      R( h, a, b, c, d, e, f, g, K(33), M(33) );
      R( g, h, a, b, c, d, e, f, K(34), M(34) );
      R( f, g, h, a, b, c, d, e, K(35), M(35) );
      R( e, f, g, h, a, b, c, d, K(36), M(36) );
      R( d, e, f, g, h, a, b, c, K(37), M(37) );
      R( c, d, e, f, g, h, a, b, K(38), M(38) );
      R( b, c, d, e, f, g, h, a, K(39), M(39) );
      R( a, b, c, d, e, f, g, h, K(40), M(40) );
      R( h, a, b, c, d, e, f, g, K(41), M(41) );
      R( g, h, a, b, c, d, e, f, K(42), M(42) );
      R( f, g, h, a, b, c, d, e, K(43), M(43) );
      R( e, f, g, h, a, b, c, d, K(44), M(44) );
      R( d, e, f, g, h, a, b, c, K(45), M(45) );
      R( c, d, e, f, g, h, a, b, K(46), M(46) );
      R( b, c, d, e, f, g, h, a, K(47), M(47) );
      R( a, b, c, d, e, f, g, h, K(48), M(48) );
      R( h, a, b, c, d, e, f, g, K(49), M(49) );
      R( g, h, a, b, c, d, e, f, K(50), M(50) );
      R( f, g, h, a, b, c, d, e, K(51), M(51) );
      R( e, f, g, h, a, b, c, d, K(52), M(52) );
      R( d, e, f, g, h, a, b, c, K(53), M(53) );
      R( c, d, e, f, g, h, a, b, K(54), M(54) );
      R( b, c, d, e, f, g, h, a, K(55), M(55) );
      R( a, b, c, d, e, f, g, h, K(56), M(56) );
      R( h, a, b, c, d, e, f, g, K(57), M(57) );
      R( g, h, a, b, c, d, e, f, K(58), M(58) );
      R( f, g, h, a, b, c, d, e, K(59), M(59) );
      R( e, f, g, h, a, b, c, d, K(60), M(60) );
      R( d, e, f, g, h, a, b, c, K(61), M(61) );
      R( c, d, e, f, g, h, a, b, K(62), M(62) );
      R( b, c, d, e, f, g, h, a, K(63), M(63) );
      R( a, b, c, d, e, f, g, h, K(64), M(64) );
      R( h, a, b, c, d, e, f, g, K(65), M(65) );
      R( g, h, a, b, c, d, e, f, K(66), M(66) );
      R( f, g, h, a, b, c, d, e, K(67), M(67) );
      R( e, f, g, h, a, b, c, d, K(68), M(68) );
      R( d, e, f, g, h, a, b, c, K(69), M(69) );
      R( c, d, e, f, g, h, a, b, K(70), M(70) );
      R( b, c, d, e, f, g, h, a, K(71), M(71) );
      R( a, b, c, d, e, f, g, h, K(72), M(72) );
      R( h, a, b, c, d, e, f, g, K(73), M(73) );
      R( g, h, a, b, c, d, e, f, K(74), M(74) );
      R( f, g, h, a, b, c, d, e, K(75), M(75) );
      R( e, f, g, h, a, b, c, d, K(76), M(76) );
      R( d, e, f, g, h, a, b, c, K(77), M(77) );
      R( c, d, e, f, g, h, a, b, K(78), M(78) );
      R( b, c, d, e, f, g, h, a, K(79), M(79) );

      a = ctx->state[0] += a;
      b = ctx->state[1] += b;
      c = ctx->state[2] += c;
      d = ctx->state[3] += d;
      e = ctx->state[4] += e;
      f = ctx->state[5] += f;
      g = ctx->state[6] += g;
      h = ctx->state[7] += h;
    }
}