/*
 *  FIPS-180-2 compliant SHA-256 implementation
 *  written by Christophe Devine
 *
 *  This code has been distributed as PUBLIC DOMAIN.
 *
 *  Although normally licensed under the GPL on the author's web site,
 *  he has given me permission to distribute it as public domain as 
 *  part of md5deep. THANK YOU! Software authors are encouraged to
 *  use the GPL'ed version of this code available at:
 *  http://www.cr0.net:8040/code/crypto/sha256/ whenever possible.
 */

/* $Id$ */

#include <string.h>
#include "sha256.h"


void hash_init_sha256(void * ctx)
{
    sha256_starts((context_sha256_t *)ctx);
}

void hash_update_sha256(void * ctx, const unsigned char *buf, size_t len)
{
  sha256_update((context_sha256_t *)ctx,buf,(uint32_t) len);
}

void hash_final_sha256(void * ctx, unsigned char *digest)
{
  sha256_finish((context_sha256_t *)ctx, digest);
}



#define GET_UINT32(n,b,i)                       \
{                                               \
    (n) = ( (uint32_t) (b)[(i)    ] << 24 )       \
        | ( (uint32_t) (b)[(i) + 1] << 16 )       \
        | ( (uint32_t) (b)[(i) + 2] <<  8 )       \
        | ( (uint32_t) (b)[(i) + 3]       );      \
}

#define PUT_UINT32(n,b,i)                       \
{                                               \
    (b)[(i)    ] = (uint8_t) ( (n) >> 24 );       \
    (b)[(i) + 1] = (uint8_t) ( (n) >> 16 );       \
    (b)[(i) + 2] = (uint8_t) ( (n) >>  8 );       \
    (b)[(i) + 3] = (uint8_t) ( (n)       );       \
}

void sha256_starts( context_sha256_t *ctx )
{
  ctx->total[0] = 0;
  ctx->total[1] = 0;

  ctx->state[0] = 0x6A09E667;
  ctx->state[1] = 0xBB67AE85;
  ctx->state[2] = 0x3C6EF372;
  ctx->state[3] = 0xA54FF53A;
  ctx->state[4] = 0x510E527F;
  ctx->state[5] = 0x9B05688C;
  ctx->state[6] = 0x1F83D9AB;
  ctx->state[7] = 0x5BE0CD19;
}

void sha256_process( context_sha256_t *ctx, const uint8_t data[64] );
void sha256_process( context_sha256_t *ctx, const uint8_t data[64] )
{
  uint32_t temp1, temp2, W[64];
  uint32_t A, B, C, D, E, F, G, H;

  GET_UINT32( W[0],  data,  0 );
  GET_UINT32( W[1],  data,  4 );
  GET_UINT32( W[2],  data,  8 );
  GET_UINT32( W[3],  data, 12 );
  GET_UINT32( W[4],  data, 16 );
  GET_UINT32( W[5],  data, 20 );
  GET_UINT32( W[6],  data, 24 );
  GET_UINT32( W[7],  data, 28 );
  GET_UINT32( W[8],  data, 32 );
  GET_UINT32( W[9],  data, 36 );
  GET_UINT32( W[10], data, 40 );
  GET_UINT32( W[11], data, 44 );
  GET_UINT32( W[12], data, 48 );
  GET_UINT32( W[13], data, 52 );
  GET_UINT32( W[14], data, 56 );
  GET_UINT32( W[15], data, 60 );

#define  SHR(x,n) ((x & 0xFFFFFFFF) >> n)
#define ROTR(x,n) (SHR(x,n) | (x << (32 - n)))

#define S0(x) (ROTR(x, 7) ^ ROTR(x,18) ^  SHR(x, 3))
#define S1(x) (ROTR(x,17) ^ ROTR(x,19) ^  SHR(x,10))

#define S2(x) (ROTR(x, 2) ^ ROTR(x,13) ^ ROTR(x,22))
#define S3(x) (ROTR(x, 6) ^ ROTR(x,11) ^ ROTR(x,25))

#define F0(x,y,z) ((x & y) | (z & (x | y)))
#define F1(x,y,z) (z ^ (x & (y ^ z)))

#define R(t)                                    \
(                                               \
    W[t] = S1(W[t -  2]) + W[t -  7] +          \
           S0(W[t - 15]) + W[t - 16]            \
)

#define P(a,b,c,d,e,f,g,h,x,K)                  \
{                                               \
    temp1 = h + S3(e) + F1(e,f,g) + K + x;      \
    temp2 = S2(a) + F0(a,b,c);                  \
    d += temp1; h = temp1 + temp2;              \
}

  A = ctx->state[0];
  B = ctx->state[1];
  C = ctx->state[2];
  D = ctx->state[3];
  E = ctx->state[4];
  F = ctx->state[5];
  G = ctx->state[6];
  H = ctx->state[7];

  P( A, B, C, D, E, F, G, H, W[ 0], 0x428A2F98 );
  P( H, A, B, C, D, E, F, G, W[ 1], 0x71374491 );
  P( G, H, A, B, C, D, E, F, W[ 2], 0xB5C0FBCF );
  P( F, G, H, A, B, C, D, E, W[ 3], 0xE9B5DBA5 );
  P( E, F, G, H, A, B, C, D, W[ 4], 0x3956C25B );
  P( D, E, F, G, H, A, B, C, W[ 5], 0x59F111F1 );
  P( C, D, E, F, G, H, A, B, W[ 6], 0x923F82A4 );
  P( B, C, D, E, F, G, H, A, W[ 7], 0xAB1C5ED5 );
  P( A, B, C, D, E, F, G, H, W[ 8], 0xD807AA98 );
  P( H, A, B, C, D, E, F, G, W[ 9], 0x12835B01 );
  P( G, H, A, B, C, D, E, F, W[10], 0x243185BE );
  P( F, G, H, A, B, C, D, E, W[11], 0x550C7DC3 );
  P( E, F, G, H, A, B, C, D, W[12], 0x72BE5D74 );
  P( D, E, F, G, H, A, B, C, W[13], 0x80DEB1FE );
  P( C, D, E, F, G, H, A, B, W[14], 0x9BDC06A7 );
  P( B, C, D, E, F, G, H, A, W[15], 0xC19BF174 );
  P( A, B, C, D, E, F, G, H, R(16), 0xE49B69C1 );
  P( H, A, B, C, D, E, F, G, R(17), 0xEFBE4786 );
  P( G, H, A, B, C, D, E, F, R(18), 0x0FC19DC6 );
  P( F, G, H, A, B, C, D, E, R(19), 0x240CA1CC );
  P( E, F, G, H, A, B, C, D, R(20), 0x2DE92C6F );
  P( D, E, F, G, H, A, B, C, R(21), 0x4A7484AA );
  P( C, D, E, F, G, H, A, B, R(22), 0x5CB0A9DC );
  P( B, C, D, E, F, G, H, A, R(23), 0x76F988DA );
  P( A, B, C, D, E, F, G, H, R(24), 0x983E5152 );
  P( H, A, B, C, D, E, F, G, R(25), 0xA831C66D );
  P( G, H, A, B, C, D, E, F, R(26), 0xB00327C8 );
  P( F, G, H, A, B, C, D, E, R(27), 0xBF597FC7 );
  P( E, F, G, H, A, B, C, D, R(28), 0xC6E00BF3 );
  P( D, E, F, G, H, A, B, C, R(29), 0xD5A79147 );
  P( C, D, E, F, G, H, A, B, R(30), 0x06CA6351 );
  P( B, C, D, E, F, G, H, A, R(31), 0x14292967 );
  P( A, B, C, D, E, F, G, H, R(32), 0x27B70A85 );
  P( H, A, B, C, D, E, F, G, R(33), 0x2E1B2138 );
  P( G, H, A, B, C, D, E, F, R(34), 0x4D2C6DFC );
  P( F, G, H, A, B, C, D, E, R(35), 0x53380D13 );
  P( E, F, G, H, A, B, C, D, R(36), 0x650A7354 );
  P( D, E, F, G, H, A, B, C, R(37), 0x766A0ABB );
  P( C, D, E, F, G, H, A, B, R(38), 0x81C2C92E );
  P( B, C, D, E, F, G, H, A, R(39), 0x92722C85 );
  P( A, B, C, D, E, F, G, H, R(40), 0xA2BFE8A1 );
  P( H, A, B, C, D, E, F, G, R(41), 0xA81A664B );
  P( G, H, A, B, C, D, E, F, R(42), 0xC24B8B70 );
  P( F, G, H, A, B, C, D, E, R(43), 0xC76C51A3 );
  P( E, F, G, H, A, B, C, D, R(44), 0xD192E819 );
  P( D, E, F, G, H, A, B, C, R(45), 0xD6990624 );
  P( C, D, E, F, G, H, A, B, R(46), 0xF40E3585 );
  P( B, C, D, E, F, G, H, A, R(47), 0x106AA070 );
  P( A, B, C, D, E, F, G, H, R(48), 0x19A4C116 );
  P( H, A, B, C, D, E, F, G, R(49), 0x1E376C08 );
  P( G, H, A, B, C, D, E, F, R(50), 0x2748774C );
  P( F, G, H, A, B, C, D, E, R(51), 0x34B0BCB5 );
  P( E, F, G, H, A, B, C, D, R(52), 0x391C0CB3 );
  P( D, E, F, G, H, A, B, C, R(53), 0x4ED8AA4A );
  P( C, D, E, F, G, H, A, B, R(54), 0x5B9CCA4F );
  P( B, C, D, E, F, G, H, A, R(55), 0x682E6FF3 );
  P( A, B, C, D, E, F, G, H, R(56), 0x748F82EE );
  P( H, A, B, C, D, E, F, G, R(57), 0x78A5636F );
  P( G, H, A, B, C, D, E, F, R(58), 0x84C87814 );
  P( F, G, H, A, B, C, D, E, R(59), 0x8CC70208 );
  P( E, F, G, H, A, B, C, D, R(60), 0x90BEFFFA );
  P( D, E, F, G, H, A, B, C, R(61), 0xA4506CEB );
  P( C, D, E, F, G, H, A, B, R(62), 0xBEF9A3F7 );
  P( B, C, D, E, F, G, H, A, R(63), 0xC67178F2 );

  ctx->state[0] += A;
  ctx->state[1] += B;
  ctx->state[2] += C;
  ctx->state[3] += D;
  ctx->state[4] += E;
  ctx->state[5] += F;
  ctx->state[6] += G;
  ctx->state[7] += H;
}

void sha256_update( context_sha256_t *ctx, const uint8_t *input, uint32_t length )
{
  uint32_t left, fill;

  if( ! length ) return;

  left = ctx->total[0] & 0x3F;
  fill = 64 - left;

  ctx->total[0] += length;
  ctx->total[0] &= 0xFFFFFFFF;

  if( ctx->total[0] < length )
    ctx->total[1]++;

  if( left && length >= fill )
    {
      memcpy( (void *) (ctx->buffer + left),
	      (const void *) input, fill );
      sha256_process( ctx, ctx->buffer );
      length -= fill;
      input  += fill;
      left = 0;
    }

  while( length >= 64 )
    {
      sha256_process( ctx, input );
      length -= 64;
      input  += 64;
    }

  if( length )
    {
      memcpy( (void *) (ctx->buffer + left),
	      (const void *) input, length );
    }
}

static uint8_t sha256_padding[64] =
  {
    0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
  };

void sha256_finish( context_sha256_t *ctx, uint8_t digest[32] )
{
  uint32_t last, padn;
  uint32_t high, low;
  uint8_t msglen[8];

  high = ( ctx->total[0] >> 29 )
    | ( ctx->total[1] <<  3 );
  low  = ( ctx->total[0] <<  3 );

  PUT_UINT32( high, msglen, 0 );
  PUT_UINT32( low,  msglen, 4 );

  last = ctx->total[0] & 0x3F;
  padn = ( last < 56 ) ? ( 56 - last ) : ( 120 - last );

  sha256_update( ctx, sha256_padding, padn );
  sha256_update( ctx, msglen, 8 );

  PUT_UINT32( ctx->state[0], digest,  0 );
  PUT_UINT32( ctx->state[1], digest,  4 );
  PUT_UINT32( ctx->state[2], digest,  8 );
  PUT_UINT32( ctx->state[3], digest, 12 );
  PUT_UINT32( ctx->state[4], digest, 16 );
  PUT_UINT32( ctx->state[5], digest, 20 );
  PUT_UINT32( ctx->state[6], digest, 24 );
  PUT_UINT32( ctx->state[7], digest, 28 );
}

#ifdef TEST

#include <stdlib.h>
#include <stdio.h>

/*
 * those are the standard FIPS-180-2 test vectors
 */

static char *msg[] = 
  {
    "abc",
    "abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq",
    NULL
  };

static char *val[] =
  {
    "ba7816bf8f01cfea414140de5dae2223" \
    "b00361a396177a9cb410ff61f20015ad",
    "248d6a61d20638b8e5c026930c3e6039" \
    "a33ce45964ff2167f6ecedd419db06c1",
    "cdc76e5c9914fb9281a1c7e284d73e67" \
    "f1809a48a497200e046d39ccc7112cd0"
  };

int main( int argc, char *argv[] )
{
  FILE *f;
  int i, j;
  char output[65];
  context_sha256_t ctx;
  unsigned char buf[1000];
  unsigned char sha256sum[32];

  if( argc < 2 )
    {
      printf( "\n SHA-256 Validation Tests:\n\n" );

      for( i = 0; i < 3; i++ )
        {
	  printf( " Test %d ", i + 1 );

	  sha256_starts( &ctx );

	  if( i < 2 )
            {
	      sha256_update( &ctx, (uint8_t *) msg[i],
			     strlen( msg[i] ) );
            }
	  else
            {
	      memset( buf, 'a', 1000 );

	      for( j = 0; j < 1000; j++ )
                {
		  sha256_update( &ctx, (uint8_t *) buf, 1000 );
                }
            }

	  sha256_finish( &ctx, sha256sum );

	  for( j = 0; j < 32; j++ )
            {
	      sprintf( output + j * 2, "%02x", sha256sum[j] );
            }

	  if( memcmp( output, val[i], 64 ) )
            {
	      printf( "failed!\n" );
	      return( 1 );
            }

	  printf( "passed.\n" );
        }

      printf( "\n" );
    }
  else
    {
      if( ! ( f = fopen( argv[1], "rb" ) ) )
        {
	  perror( "fopen" );
	  return( 1 );
        }

      sha256_starts( &ctx );

      while( ( i = fread( buf, 1, sizeof( buf ), f ) ) > 0 )
        {
	  sha256_update( &ctx, buf, i );
        }

      sha256_finish( &ctx, sha256sum );

      for( j = 0; j < 32; j++ )
        {
	  printf( "%02x", sha256sum[j] );
        }

      printf( "  %s\n", argv[1] );
    }

  return( 0 );
}

#endif
