/*
    FIPS-180-1 compliant SHA-1 implementation

    Based on XySSL: Copyright (C) 2006-2008  Christophe Devine

    Copyright (C) 2009  Paul Bakker <polarssl_maintainer at polarssl dot org>

    All rights reserved.

    Redistribution and use in source and binary forms, with or without
    modification, are permitted provided that the following conditions
    are met:

 *    * Redistributions of source code must retain the above copyright
        notice, this list of conditions and the following disclaimer.
 *    * Redistributions in binary form must reproduce the above copyright
        notice, this list of conditions and the following disclaimer in the
        documentation and/or other materials provided with the distribution.
 *    * Neither the names of PolarSSL or XySSL nor the names of its contributors
        may be used to endorse or promote products derived from this software
        without specific prior written permission.

    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
    FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
    OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
    SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
    TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
    PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
    LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
    NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
    SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/*
    The SHA-1 standard was published by NIST in 1993.

    http://www.itl.nist.gov/fipspubs/fip180-1.htm
*/

#include "sha1.h"

#include <string.h>

/*
   32-bit integer manipulation macros (big endian)
*/
#ifndef GET_ULONG_BE
#define GET_ULONG_BE(n,b,i)                             \
{                                                       \
    (n) = ( (unsigned long) (b)[(i)    ] << 24 )        \
        | ( (unsigned long) (b)[(i) + 1] << 16 )        \
        | ( (unsigned long) (b)[(i) + 2] <<  8 )        \
        | ( (unsigned long) (b)[(i) + 3]       );       \
}
#endif

#ifndef PUT_ULONG_BE
#define PUT_ULONG_BE(n,b,i)                             \
{                                                       \
    (b)[(i)    ] = (unsigned char) ( (n) >> 24 );       \
    (b)[(i) + 1] = (unsigned char) ( (n) >> 16 );       \
    (b)[(i) + 2] = (unsigned char) ( (n) >>  8 );       \
    (b)[(i) + 3] = (unsigned char) ( (n)       );       \
}
#endif

/*
   SHA-1 context setup
*/
void sha1_starts( sha1_context *ctx )
{
  ctx->total[0] = 0;
  ctx->total[1] = 0;

  ctx->state[0] = 0x67452301;
  ctx->state[1] = 0xEFCDAB89;
  ctx->state[2] = 0x98BADCFE;
  ctx->state[3] = 0x10325476;
  ctx->state[4] = 0xC3D2E1F0;
}

static void sha1_process( sha1_context *ctx, const unsigned char data[64] )
{
  unsigned long temp, W[16], A, B, C, D, E;

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

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

#define R(t)                                            \
(                                                       \
    temp = W[(t -  3) & 0x0F] ^ W[(t - 8) & 0x0F] ^     \
           W[(t - 14) & 0x0F] ^ W[ t      & 0x0F],      \
    ( W[t & 0x0F] = S(temp,1) )                         \
)

#define P(a,b,c,d,e,x)                                  \
{                                                       \
    e += S(a,5) + F(b,c,d) + K + x; b = S(b,30);        \
}

  A = ctx->state[0];
  B = ctx->state[1];
  C = ctx->state[2];
  D = ctx->state[3];
  E = ctx->state[4];

#define F(x,y,z) (z ^ (x & (y ^ z)))
#define K 0x5A827999

  P( A, B, C, D, E, W[0]  );
  P( E, A, B, C, D, W[1]  );
  P( D, E, A, B, C, W[2]  );
  P( C, D, E, A, B, W[3]  );
  P( B, C, D, E, A, W[4]  );
  P( A, B, C, D, E, W[5]  );
  P( E, A, B, C, D, W[6]  );
  P( D, E, A, B, C, W[7]  );
  P( C, D, E, A, B, W[8]  );
  P( B, C, D, E, A, W[9]  );
  P( A, B, C, D, E, W[10] );
  P( E, A, B, C, D, W[11] );
  P( D, E, A, B, C, W[12] );
  P( C, D, E, A, B, W[13] );
  P( B, C, D, E, A, W[14] );
  P( A, B, C, D, E, W[15] );
  P( E, A, B, C, D, R(16) );
  P( D, E, A, B, C, R(17) );
  P( C, D, E, A, B, R(18) );
  P( B, C, D, E, A, R(19) );

#undef K
#undef F

#define F(x,y,z) (x ^ y ^ z)
#define K 0x6ED9EBA1

  P( A, B, C, D, E, R(20) );
  P( E, A, B, C, D, R(21) );
  P( D, E, A, B, C, R(22) );
  P( C, D, E, A, B, R(23) );
  P( B, C, D, E, A, R(24) );
  P( A, B, C, D, E, R(25) );
  P( E, A, B, C, D, R(26) );
  P( D, E, A, B, C, R(27) );
  P( C, D, E, A, B, R(28) );
  P( B, C, D, E, A, R(29) );
  P( A, B, C, D, E, R(30) );
  P( E, A, B, C, D, R(31) );
  P( D, E, A, B, C, R(32) );
  P( C, D, E, A, B, R(33) );
  P( B, C, D, E, A, R(34) );
  P( A, B, C, D, E, R(35) );
  P( E, A, B, C, D, R(36) );
  P( D, E, A, B, C, R(37) );
  P( C, D, E, A, B, R(38) );
  P( B, C, D, E, A, R(39) );

#undef K
#undef F

#define F(x,y,z) ((x & y) | (z & (x | y)))
#define K 0x8F1BBCDC

  P( A, B, C, D, E, R(40) );
  P( E, A, B, C, D, R(41) );
  P( D, E, A, B, C, R(42) );
  P( C, D, E, A, B, R(43) );
  P( B, C, D, E, A, R(44) );
  P( A, B, C, D, E, R(45) );
  P( E, A, B, C, D, R(46) );
  P( D, E, A, B, C, R(47) );
  P( C, D, E, A, B, R(48) );
  P( B, C, D, E, A, R(49) );
  P( A, B, C, D, E, R(50) );
  P( E, A, B, C, D, R(51) );
  P( D, E, A, B, C, R(52) );
  P( C, D, E, A, B, R(53) );
  P( B, C, D, E, A, R(54) );
  P( A, B, C, D, E, R(55) );
  P( E, A, B, C, D, R(56) );
  P( D, E, A, B, C, R(57) );
  P( C, D, E, A, B, R(58) );
  P( B, C, D, E, A, R(59) );

#undef K
#undef F

#define F(x,y,z) (x ^ y ^ z)
#define K 0xCA62C1D6

  P( A, B, C, D, E, R(60) );
  P( E, A, B, C, D, R(61) );
  P( D, E, A, B, C, R(62) );
  P( C, D, E, A, B, R(63) );
  P( B, C, D, E, A, R(64) );
  P( A, B, C, D, E, R(65) );
  P( E, A, B, C, D, R(66) );
  P( D, E, A, B, C, R(67) );
  P( C, D, E, A, B, R(68) );
  P( B, C, D, E, A, R(69) );
  P( A, B, C, D, E, R(70) );
  P( E, A, B, C, D, R(71) );
  P( D, E, A, B, C, R(72) );
  P( C, D, E, A, B, R(73) );
  P( B, C, D, E, A, R(74) );
  P( A, B, C, D, E, R(75) );
  P( E, A, B, C, D, R(76) );
  P( D, E, A, B, C, R(77) );
  P( C, D, E, A, B, R(78) );
  P( B, C, D, E, A, R(79) );

#undef K
#undef F

  ctx->state[0] += A;
  ctx->state[1] += B;
  ctx->state[2] += C;
  ctx->state[3] += D;
  ctx->state[4] += E;
}

/*
   SHA-1 process buffer
*/
void sha1_update( sha1_context *ctx, const unsigned char *input, int ilen )
{
  int fill;
  unsigned long left;

  if ( ilen <= 0 )
    return;

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

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

  if ( ctx->total[0] < (unsigned long) ilen )
    ctx->total[1]++;

  if ( left && ilen >= fill )
  {
    memcpy( (void *) (ctx->buffer + left),
            input, fill );
    sha1_process( ctx, ctx->buffer );
    input += fill;
    ilen  -= fill;
    left = 0;
  }

  while ( ilen >= 64 )
  {
    sha1_process( ctx, input );
    input += 64;
    ilen  -= 64;
  }

  if ( ilen > 0 )
  {
    memcpy( (void *) (ctx->buffer + left),
            input, ilen );
  }
}

static const unsigned char sha1_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
};

/*
   SHA-1 final digest
*/
void sha1_finish( sha1_context *ctx, unsigned char output[SHA1_BUFFER_SIZE] )
{
  unsigned long last, padn;
  unsigned long high, low;
  unsigned char msglen[8];

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

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

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

  sha1_update( ctx, sha1_padding, padn );
  sha1_update( ctx, msglen, 8 );

  PUT_ULONG_BE( ctx->state[0], output,  0 );
  PUT_ULONG_BE( ctx->state[1], output,  4 );
  PUT_ULONG_BE( ctx->state[2], output,  8 );
  PUT_ULONG_BE( ctx->state[3], output, 12 );
  PUT_ULONG_BE( ctx->state[4], output, 16 );
}

/*
   output = SHA-1( input buffer )
*/
void sha1( unsigned char *input, int ilen, unsigned char output[SHA1_BUFFER_SIZE] )
{
  sha1_context ctx;

  sha1_starts( &ctx );
  sha1_update( &ctx, input, ilen );
  sha1_finish( &ctx, output );
}
